RESUMEN
A direct and specific identification of porcine pancreatic kallikrein by high-performance hydrophobic chromatography is proposed; the minimum amount which can be injected is 2.5 U. An application to the quantitative determination of the enzyme by high-performance size-exclusion chromatography is reported; the method is precise with a mean coefficient of variation of 2.8% and the minimum amount which can be injected is 0.02 U of kallikrein. The results obtained with determinations in real biological samples (porcine pancreatic powder and human urine) are reported. The method is based on direct and specific chromatographic signals and does not destroy the biological activity of this enzyme.
Asunto(s)
Calicreínas/metabolismo , Páncreas/enzimología , Animales , Cromatografía en Gel , Cromatografía Líquida de Alta Presión , Humanos , Calicreínas/orina , Reproducibilidad de los Resultados , Espectrofotometría Ultravioleta , PorcinosRESUMEN
A titrimetric method for the standardisation of three human urinary trypsin inhibitors (UTIs) has been developed. The same substances are also present in human plasma, and their amounts in such biological fluids are of bioclinical interest. The method is based on the direct titration of each UTI with a solution of bovine trypsin of known molarity, and monitoring the decreasing residual amounts of the inhibitor by reversed-phase high-performance liquid chromatography. The proposed method provides a suitable alternative to the traditional enzymic - spectrophotometric method. Mean within-day and between-day coefficients of variation and the limit of determination for the standardisation of each UTI are reported.
Asunto(s)
Inhibidores de Tripsina/análisis , Tampones (Química) , Cromatografía Líquida de Alta Presión , Indicadores y ReactivosRESUMEN
A method for the determination of surface contamination of various materials by 3H and 99Tc is reported. Both 3H and 99Tcm are widely used in chemical and clinical applications. The isotopes 99Tc, the decay product of 99Tcm, and 3H are soft beta-emitter radionuclides and the use of unsealed sources can frequently produce contamination and excessive internal dosing for workers. The removal of radionuclides from surfaces was effected with attapulgite, a clay with a high absorption capacity for many organic and inorganic substances. The determination was carried out by extracting the absorbed radionuclide from the clay and then measuring it in a beta-scintillation counter. The determination limits of the method, 20 Bq cm-2 for 3H and 100 Bq cm-2 for 99Tc, are below the "derived working limits" for these radionuclides.
Asunto(s)
Compuestos de Magnesio , Radioisótopos/análisis , Compuestos de Silicona , Magnesio , Cloruro de Polivinilo , Silicio , Tecnecio/análisis , Tritio/análisisRESUMEN
A method for the determination of aprotinin (bovine pancreatic trypsin inhibitor, BPTI) is described. The procedure involves the formation of the BPTI-trypsin complex in the presence of an excess of BPTI, quantitative separation of the residual BPTI from the mixture by affinity chromatography and identification and evaluation of the residual BPTI by reversed-phase high-performance liquid chromatography. The method is precise with a mean coefficient of variation of 4.0 and 4.3% for intra- and inter-assay runs, respectively, and has a limit of determination of 3.0 micrograms of aprotinin. The proposed method can be applied to commercial samples, even in very dilute solutions, for the standardisation of aprotinin.
