RESUMO
The study was undertaken to assess commercial thromboplastins for compliance to the WHO guidelines and to substantiate the validity of the results of a prothrombin test carried out using these thromboplastins. The test thromboplastins were shown to meet the WHO guidelines for assessment of thromboplastins. Over 5-8 years of the authors'participation in two external quality control programs (Federal External Quality Control System, Russia; 72 trials; NEQAS, United Kingdom; 60 trials), the international normalized ratio derived through the use of assessed thromboplastins did not differ from that established due to the interlaboratory consensus value of both external quality control systems. It is concluded that correct thromboplastin assessment provide accurate results of determination of prothrombin time.
Assuntos
Transtornos da Coagulação Sanguínea/diagnóstico , Tempo de Protrombina/normas , Tromboplastina , Transtornos da Coagulação Sanguínea/epidemiologia , Fidelidade a Diretrizes , Humanos , Coeficiente Internacional Normatizado , Guias de Prática Clínica como Assunto , Tempo de Protrombina/métodos , Garantia da Qualidade dos Cuidados de Saúde , Controle de Qualidade , Reprodutibilidade dos Testes , Federação Russa , Organização Mundial da SaúdeRESUMO
Recombinant plasmids containing fusion proteins composed of two different modules were constructed and expressed in Escherichia coli. The modules encoded the lactase LacA (LacZ) from the thermophilic bacterium Thermoanaerobacter ethanolicus and the cellulase CelD, a cellulose-binding module (CBM) from Anaerocellum thermophilum. The CelD CBM provides a spontaneous and strong sorption of the fusion proteins onto a cellulose carrier. The enzymatic activities of both the free LacA protein and LacA-CelD CBM fusion proteins immobilized onto the cellulose carrier were assessed. The LacA activity of the fusion protein was dependent upon its position with respect to the CBM. The highest level of lactase activity and stability was observed when the lactase domain was localized at its N terminus. A continuous-flow column reactor of lactase immobilized on a cellulose carrier was constructed, and its activity was assessed. The lactose hydrolysis rate for a 150 mM (5%) solution at a flow rate of 1 reactor volume per min was 75%, which is a value optimal for further whey transformation into glucose/galactose syrup.