Screening for Down syndrome.
Explore the source record for details and available documents.
Amniocentesis↗
Biomedical subjects
R P Ager
Publications and source records attributed to R P Ager.
Separation of oestrogen conjugates in urine and synthetic mixtures by high-performance liquid chromatographic methods.
The analytical and clinical advantages that would be expected to follow the adoption by clinical laboratories of a routine HPLC method for the partial oestriol conjugate profiling of human pregnancy urine are outlined in the Introduction. In order to ascertain if a candidate method for this assay has yet been devised, a complete survey of the published HPLC separations of oestrogen conjugate mixtures is presented, in tabular form, and discussed. From this survey it is concluded that a number of good separations of these steroids from synthetic mixtures have already been published. The third and final section of the paper contains the results of a detailed examination of those papers in which separation of oestriol conjugates present in pregnancy urine specimens have been reported. The paper is concluded with the recommendation that the method of Dixon, Lukha and Scott should be further investigated as a candidate method for adoption by clinical laboratories for the purpose of oestriol conjugate profiling.
Chromatography, High Pressure Liquid↗
Separation of oestrogens in biological fluids and synthetic mixtures on Sephadex G-type gels.
The separations achieved when mixtures of both free and conjugated oestrogens from a variety of sources are chromatographed on columns of Sephadex gel are reviewed. The molecular identities of oestrogen conjugates which have been separated from human urine by these methods are listed in Table 1. Tables 2 and 3 contain the key experimental details for a total of 26 separations of oestrogen mixtures, abstracted from the total of 20 papers which were published during the period 1961-82. Table 4 details corresponding experimental data for the separation of free oestriol (in human blood) achieved by methods involving a combined Sephadex gel and immunochemical procedure abstracted from a further two papers. A careful analysis of the separation data given in the tables leads to the initial conclusion that the elution profile depends on the expected chromatographic variables for gel filtration chromatography, namely, type of Sephadex gel, length of column, nature and amount of sample applied and the sensitivity of detection methods. However, the separation achieved by the Sephadex columns is also shown to be critically dependent on the column temperature and the pH and chemical composition of the eluent and wash solvents. These latter effects, together with the realization that the molecular weights of the oestrogens being separated are very similar, leads to the conclusion that the separations summarized in Tables 2 and 3 are all being achieved by an absorption process. This being the case, it is suggested that the time-consuming methods of gel filtration chromatography need not be used. Confirmation of this proposal is afforded by a discussion of a recent paper in which the rapid separation of the oestrogens from other components in the biological matrix (urine) was achieved by an adsorption procedure. It is suggested that in the future, separations of oestrogens in biological materials may be most rapidly achieved in combining this type of adsorption procedure with HPLC.
Body Fluids↗