[en] Of the 77 papers submitted, 69 were included in INIS. The papers included in the proceedings cover the following sessions: reagents and separation procedures; assay for free hormones; assay for biological substances; assay for drugs; data processing; intralaboratory quality control; external surveillance of assay performance; assay service in developing countries; public health applications; clinical applications; alternatives to radioassay

[en] From 1980 on, five quality-control surveys for thyroid-stimulating hormone (TSH) determinations in dried blood were performed. Ninety-six laboratories from 12 European countries took part. Each of the altogether 21 different samples consisted of three spots of dried blood spiked with the same amount of TSH. The participants were asked to give for each sample the values from two individual determinations, as well as their diagnostic classification and the type of analytical kit used. The medians of the analytical values corresponded very well to the given TSH concentrations. But the individual values and the associated diagnostic classifications differed widely. The most important factors that may have caused the large numeric variability were the pure intralaboratory as well as interlaboratory precision of analytical estimations. Moreover, the borderline of decision as between the classifications ''normal'' and ''suspicious'' was ascertained very differently in the individual laboratories. By a special statistical procedure it could be shown that a narrow range at 22 mU/L TSH was the preferred region for changing the decision for values above normal. (author)

[en] The introduction of cell-hybridization techniques by Koehler and Milstein in 1975 to produce monoclonal antibodies (MA) was a definite improvement in methodological tools of radioimmunoassay, quite apart from all other applications of this technique in immunohistochemistry, affinity chromatography, target-directed drug delivery systems etc. MAs would ideally be suited in RIAs, when the specificity is the crucial aspect of the determination. However, for reasons which are not completely understood, assays with MAs very often lack the attribute of being highly sensitive. Despite several reports in the literature on MAs against human growth hormone (HGH), none of these seem sensitive enough to be of use in clinical chemistry, where a too strongly marked specificity may even be unwanted. However, from the scientific point of view, MAs against polypeptide hormones are of great interest. An MA to HGH was developed with a sensitivity limit of 0.2 ng. The titre of the ascites fluid is higher than 1:10₆ and the specificity against human placental lactogen, human prolactin and rat growth hormone is nearly complete. A critical step of the RIA procedure is the separation of bound and free hormone. A combination of human immunoglobulin (Sandoglobulin) with polyethylene glycol gives optimal results. A Scatchard plot reveals an affinity constant of 4x10^-₁₁M-bar and a maximal binding capacity of 2x10₈cpm/μL. In conclusion, our monoclonal antibody represents an excellent investigational tool for endocrine research and it seems to be the most sensitive and specific MA to HGH described to date. However, for practical clinical applications, there seems to be little advantage of an MA over a conventional polyclonal antiserum. (author)

[en] The development of a new solid-phase separation system based on silane polymers is described. A T³ radioimmunoassay (RIA) was optimized using coated tubes with polymer coatings containing hydrophilic surface aldehyde groups for antibody coupling and a T⁴ RIA developed on the basis of surface anilino group containing particles using a suspension method. Both RIAs offer very good performances and show the variable usability of the new separation system. (author)

[en] To contribute to the standardization of anti-HB determinations, five methods of quantitative anti-HB determination were compared: CEP dilution titration; RIA dilution titration; RIA unit determination; RIA parallel-line bioassay; and determination of binding capacity by quantitative immunoelectrophoresis. Anti-HB positive sera - the same five sera, in various dilutions, were subjected to the five tests. When comparing the overall results of the different titration methods, the following may be noted. The CEP method is very insensitive and yields relatively less favourable results with HBIG preparations. This is possibly related to the absence of adequately precipitating antibodies. There is no relationship between CEP and RIA dilutions titrations: HBIG (50 IU) is the least potent in CEP, most potent in RIA. But, of course, HBIG (50 IU) is standardized by a RIA method. The RIA dilution titration yields the same overall results as the two other RIA methods (RIA units and parallel-line bioassay), yet the dilution method is less accurate because of the way in which the titre is determined (= last dilution before cut-off). The RIA units determination and the parallel-line bioassay give somewhat similar results. There seems to be a nearly constant ratio between both these numerical results: RIA units/3000 approx.= IU/mL. In the parallel-line bioassay it seems that the results cannot be interpreted for antisera produced in another animal species. (author)

[en] A simple, rapid radioimmunoassay for salivary oestriol has been developed based upon a radioiodinated tracer and a Sepharose-coupled antiserum with high specificity for oestriol and oestriol-3-conjugates. The standard curve covers the range 0.75 to 17.5 nmol/L, and assay sensitivity and precision are adequate for determination of third trimester oestriol concentrations. This assay, with a short incubation time (15 min) and a high tracer activity, has proved suitable for automation using a continuous-flow system based upon the 'Southmead System' described by Ismail and co-workers. Preliminary ether extraction is unnecessary since salivary oestriol is predominantly in the unconjugated form. Measurements of unconjugated oestriol in matched samples of plasma and saliva show an excellent correlation (r=0.95). A preliminary study has been carried out to assess the feasibility of constructing individual daily salivary oestriol profiles throughout the third trimester. Data have now been collected on normal, diabetic and other high-risk patients, and these indicate that salivary oestriol measurements provide a practical alternative to the determination of plasma unconjugated oestriol. (author)

[en] A highly specific and sensitive radioimmunoassay for the main metabolite of serotonine, 5-hydroxy indole acetic acid (5HIAA) was developed. Iodination of the analogue was performed either by coupling 5HIAA to ₁₂₅I-glycyl-tyrosine without any contact between 5HIAA and oxidation reagents or after protection of the 5-hydroxyl group by acetylation. The immunogen was synthesized by coupling first glycine to the epsilon-lysine residues of bovine serum albumin and then 5HIAA to glycine. Twenty-seven moles of 5HIAA were thus coupled. Antibodies raised in rabbits could be diluted up to 1/300,000. As expected this new class of antibodies exhibited a much greater affinity for 5HIAA-glycinamide than for 5HIAA. The chemical conversion of 5HIAA from biological samples into 5HIAA glycinamide lead to a very high specificity, demonstrated by competition experiments with 22 analogues, and to a sensitivity threshold below 5 pg exemplified by measurement of 5HIAA content in different areas of the mouse brain. (author)

[en] The problems are initially of an organizational nature concerned with obtaining necessary local support from administrators with limited funds available from socialized health budgets. Stressing the relevance of proposed techniques to national priorities in many fields would be required. Centres should be located so as to serve as wide an area as possible, and administrative obstacles in communication, clearance, transport etc. should be overcome. It is suggested that emphasis be placed on training of personnel, particularly at technician level, in selected centres within a region, and by regional training courses, so that expertise gained may be better applied to local situations. The degree of sophistication of equipment selected is seen to depend on the factors of work load and possibility for repair and maintenance. The latter problem is often best solved locally through other arrangements, such as with suppliers themselves. The main operational problem of obtaining reagents for immunoassays is aggravated by shortage of foreign exchange, and economic factors preclude the widespread use of commercial assay kits. Possibilities that may exist to resolve this by greater interdependence amongst workers within the region are hampered by a serious lack of information, and correction of this situation would result in advantages in several respects. International agencies and governments providing aid play a major role in the above matters as well as in others such as the provision of consultant services and research contracts which are considered to be of great benefit. It is stressed that a correct attitude is as important as expertise for the realization of an expert assignment. In conclusion it is suggested that under existing conditions, third-world workers could abandon the attitude of looking towards the developed countries as first choice for solutions to problems and seek to exploit the potential available among themselves for mutual benefit. (author)

[en] To establish solid-phase thyroid hormone radioimmunoassay (RIA) systems, a study on immobilization of 3,5,3'-triiodo-L-thyronine (T³) antibodies on the inner wall of polystyrene tubes and on modification of assay buffer systems has been carried out. Into a series of polystyrene tubes, a constant volume of alkaline glutaraldehyde solution was added to obtain glutaraldehyde-coated tubes by self-polymerization. The tubes were then incubated with dilute bovine gamma globulin (BGG) solution and subsequently treated again with glutaraldehyde. The tubes were further treated with dilute antibody solution to react the aldehyde residue on the wall surface with the amino groups of antibodies. After a definite time, the excess antibody solution was decanted and the tubes were washed with plenty of barbital buffer solution. Reaction parameters such as temperature, volume of the glutaraldehyde solution, pH, dilution ratio and temperature of the antibody solution etc., were controlled. The resulting antibody-coated tubes were tested with antigen bindings to verify the validity in RIA use. To the tubes, T³-₁₂₅I of high specific activity, 8-anilino-1-naphthalene-sulfonic acid (ANS), and the modified buffer solution (0.025M-bar barbital buffer, pH 8.2, containing 0.1% bovine serum albumin (BSA), 0.5% BGG, 0.02% merthiolate, 0.58% NaCl, 0.19% ethylenediaminetetraacetate (EDTA) etc.) were added and incubated with or without T³ standard doses. The percentage of the antibody-bound radioactivity (B) to the total radioactivity (T) was calculated. The average range of B/T (%) under a standard dose of up to 4 ng/mL was 30-58. The results indicated that the antibody-coated tubes are usable for solid-phase T³ RIA under the established conditions. Improvement of the binding ability of the immobilized antibody has been proved by introducing BGG as a spacer and by mixing BSA in the immobilization mixture. (author)

[en] Circulating levels of serum human growth hormone (hGH) in 17 normal healthy Thai subjects and 12 patients with Graves' disease of different clinical severity following an oral stimulation of 500 mg L-dopa were determined by radioreceptorassay (RRA) and radioimmunoassay (RIA). The average basal hGH in normal control group was 1.8+-0.8 and 2.4+-1.0 ng/mL (mean+-SD) as measured by RRA and RIA respectively. The mean maximal hGH response to L-dopa occurring between 60-90 min after drug administration was 13.9+-5.0 ng/mL by RRA and 15.6+-6.1 ng/mL by RIA. In Graves' patients, mean basal hGH was 1.4+-0.5 ng/mL by RRA and 1.6+-0.6 ng/mL by RIA with the maximal response of 4.4+-2.4 ng/mL by RRA and 4.6+-2.3 ng/mL by RIA. The hGH response to L-dopa observed in 10 of 12 Graves' patients was significantly lower than that found in 15 of 17 normal control subjects (P<0.005). Although 2 Graves' patients, one in mild and another in moderate state, exhibited good normal response to L-dopa, this study was consistent with other reports that excessive circulating thyroxine level has a direct suppressive effect on hypothalamus-pituitary regulation of hGH secretion. Quantitative comparison of the results obtained from RRA-assayable with those of RIA-assayable hGH showed no discrepancies in the mean ratio of RRA-RIA in all sera of the normal controls as well as patients studied with the correlation coefficient of 0.88. The results of this study indicated that there was a good correlation between biological and immunological activities of hGH circulating in normal subjects and Graves' patients. (author)