RESUMO
Technetium-99m-MAG3 is accepted as a renal tubular function agent. However, sporadic liver and gall bladder visualisation during its clinical use is clearly a disadvantage. HPLC-purified 99mTc-MAG3 samples exhibited appreciable hepatobiliary uptake (7%), and an elevated level of such uptake was observed in unpurified kit preparations, which was stated to be associated with the excretory property of the radiolabeled kit impurities. To verify this we attempted to quantitate the hepatobiliary uptake of the kit preparations with that of its radiolabeled components. The contribution of each component toward hepatobiliary uptake of the sample was calculated from their abundance in the chelate mixture and the individual biodistribution of the isolated components. However, the anticipated hepatobiliary uptake of different preparations of 99mTc-MAG3 calculated in this way was always lower than that of the experimental value determined directly. Further work is needed to explain the anomaly.
Assuntos
Vesícula Biliar/metabolismo , Fígado/metabolismo , Tecnécio Tc 99m Mertiatida/farmacocinética , Animais , Cromatografia Líquida de Alta Pressão , Ditionita , Vesícula Biliar/diagnóstico por imagem , Indicadores e Reagentes , Mucosa Intestinal/metabolismo , Rim/metabolismo , Fígado/diagnóstico por imagem , Cintilografia , Ratos , Ratos Sprague-Dawley , Tecnécio Tc 99m Mertiatida/síntese química , Tecnécio Tc 99m Mertiatida/isolamento & purificação , Distribuição TecidualRESUMO
We report on the superiority of a radioimmunoassay (RIA) system wherein the second antibody (Ab2) is incorporated as a pre-incubated complex with the primary antibody (Ab1) for the assay of haptens like triiodothyronine (T3) and thyroxine (T4). Separation of the antibody bound and free antigen (Ag) was accomplished by 8% polyethylene glycol (PEG) (final concentration) following a single incubation of less than 1 h. The other advantages of this system are a 15-fold reduction in the quantity of Ab2 (without any need for increasing the concentration of PEG) and the consequent savings in cost.
Assuntos
Radioimunoensaio/métodos , Hormônios Tireóideos/análise , Custos e Análise de Custo , Humanos , Kit de Reagentes para Diagnóstico/economiaRESUMO
125I labelled monoclonal antibody (MoAb) to thyroid stimulating hormone (TSH) was used as a tracer for assessing the suitability of polyethylene glycol (PEG) for precipitation of MoAb and MoAb-antigen (AG) complexes. It was found that PEG can be advantageously used under certain conditions favouring insolubility and could thus be a non-specific separation reagent for radioimmunoassays based on MoAbs.
Assuntos
Anticorpos Monoclonais/isolamento & purificação , Complexo Antígeno-Anticorpo , Precipitação Química , Imunoensaio/métodos , Radioisótopos do Iodo , PolietilenoglicóisRESUMO
A previous method was modified to obtain [99mTc(TBI)6]+ by reacting Zn(TBI)2Br2 directly with 99mTcO4- in the presence of Sn2+ ions. [Cu(TBI)4]Cl was next used as a source of TBI. On reaction with 99mTcO4- and Sn2+ ions for 3 min at 100 degrees C, [99mTc(TBI)6]+ product of radiochemical purity greater than 90% and yield greater than 70% was obtained. Data of biodistribution in rats (2-2.5% in heart) and biokinetics in rabbits were satisfactory. The kit formulation was found to be stable and also safe for administration.
