Radioimmunoassay of angiotensin-II: methodology and standardization.

The study was planned to set up and standardize the radioimmunoassay of Ang-II and to validate the procedure in terms of precision, sensitivity, specificity and recovery. The application of the developed assay was studied in normal healthy volunteers and in patients of renovascular hypertension (RVHT) and renal hypertension (RH). Synthetic human Ang-II was coupled to BSA by carbodimide condensation to get the hapten carrier conjugate which was injected in rabbits to raise the antibodies. The titre of 1:250 showed significant binding (56.79%) and was used for the assay. The sensitivity of the assay was 2 pg/ml and cross-reactivity with analogues of Ang-II was minimum. Mean Ang-II levels in normal subjects was 16 +/- 3.6 pg/ml. In patients of RVHT and RH, the peripheral blood Ang-II levels were found to be 876 +/- 8.6 and 108 +/- 2.3 pg/ml respectively. In patients of unilateral RVHT, renal vein Ang-II levels of the affected side were significantly higher than the unaffected side (P < 0.001). The results indicate that unextracted samples can be successfully utilized to estimate Ang-II levels.

Laboratory diagnosis of congenital and maternal rubella infection: a review.

Physicians are aware of the congenital rubella syndrome. Serodiagnosis is usually used to detect rubella infection in pregnant women and their fetuses. Although being considered the cornerstone of serodiagnosis, the hemagglutination inhibition test is gradually being replaced by new more convenient methods. Tests to detect IgM eliminate the need for paired sera to diagnose acute rubella infection. However, because of the possibilities of false positive, IgM results should be interpreted with caution. Detection of IgM in cord blood and new genetic technology made the diagnosis of infection in utero possible. The evidence of reinfection in people considered to be immune is abundant; however, discovering new antigenic determinants correlating with immunity may solve the problem and a new vaccine and antibody test that is truly associated with immunity will be available in the future.

Computerized quality control of radioimmunoassay in Korea

Automated data processing and quality control of radioimmunoassays offer not only increased speed but also a more thorough and statistically rigorous analysis of results. An external quality assessment scheme for serum thyroxine, triiodothyronine and thyroid stimulating hormone (TSH) assays was performed in five nuclear medicine laboratories in Korea to compare with the assay performances of the World Health Organization Radioimmunoassay Program. The required radioimmunoassay kits were supplied through the International Atomic Energy Agency (IAEA). We have determined the weighted root mean squared error, and variance ratio as the indices of standard curve and also the average batch coefficient of variation (ABCV) as the parameters of response error relationship curve and precision profile. There was a good fit for the triiodothyronine assay, but 3 of 5 laboratories showed possible bad fit in the T4 and TSH assay systems. The ABCV was less than 5 percent for the T3 and T4 assay system, however for the TSH system, only 1 laboratory showed the ABCV value of less than 5 percent. We have also calculated the within batch variation (drift) and between laboratory variations.

Computerized quality control of radioimmunoassay in Korea

Automated data processing and quality control of radioimmunoassays offer not only increased speed but also a more thorough and statistically rigorous analysis of results. An external quality assessment scheme for serum thyroxine, triiodothyronine and thyroid stimulating hormone (TSH) assays was performed in five nuclear medicine laboratories in Korea to compare with the assay performances of the World Health Organization Radioimmunoassay Program. The required radioimmunoassay kits were supplied through the International Atomic Energy Agency (IAEA). We have determined the weighted root mean squared error, and variance ratio as the indices of standard curve and also the average batch coefficient of variation (ABCV) as the parameters of response error relationship curve and precision profile. There was a good fit for the triiodothyronine assay, but 3 of 5 laboratories showed possible bad fit in the T4 and TSH assay systems. The ABCV was less than 5 percent for the T3 and T4 assay system, however for the TSH system, only 1 laboratory showed the ABCV value of less than 5 percent. We have also calculated the within batch variation (drift) and between laboratory variations.

Montagem e padronizaçäo do radioimunoensaio do ACTH plasmático / Mounting and standardization of radioimmunoassay of plasmatic ACTH

Esta investigaçäo compreendeu a padronizaçäo da extraçäo e do radioimunoensaio do ACTH plasmático, ainda näo realizados no Brasil. A extraçäo foi feita com ácido silícico ativado com posterior deadsorçäo com ácido clorídrico/acetona. O RiE utilizou um anticorpo central contra a seqüência 11-24 do ACTH e o padräo de marcaçäo e das curvas padröes foi o ACTH (1-39) humano sintético. Os resultados permitiram as seguintes conclusöes: a. na extraçäo do ACTH do plasma através do ácido silícico, a maior perda ocorreu na fase de adsorçäo e pouco nas outras fases, sendo que em 22 extraçöes consecutivas a recuperaçäo final foi em média 60,7%; b. as curvas padröes extraídas foram paralelas às curvas em tampäo, e os extratos näo modificaram os blanks ou o zero, indicando ausência de interferências inespecíficas da extraçäo do RiE; c. O RiE ralizado com pré-incubaçäo de 67 horas apresentou uma sensibilidade média de 3,3 pg/tubo (7,7 pg/ml plasma). Os coeficientes de variaçäo intra-ensaio estiveram entre 6,3 e 12,3%, e o interensaio foi de 18,3%. A replicaçäo, no intervalo de 13 a 4.260 pg/ml, apresentou um coeficiente de correlaçäo de 0,99. No conjunto, concluímos que o RiE do ACTH padronizado neste trabalho é confiável, podendo ser utilizado em diagnóstico e pesquisa