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Biomedical subjects

M F Burke

Publications and source records attributed to M F Burke.

6 recordsLinked to original sources

Changing patterns in the presentation of breast cancer over 25 years.

The clinical stage at presentation of 280 women with histologically proven breast cancer is reviewed over a 25 year time span from 1962 to 1987. The data from 240 unscreened patients, including 87 women from the period 1962 to 1963, 103 women from 1981 to 1982, and 50 women from 1986 to 1987 demonstrate a chronologically based improvement in the stage of disease at presentation over the 25 years. Specifically, over that period, there was a fall in the mean tumour diameter, a reduction in the proportion of patients with involved axillary nodes, and a greater percentage of patients with Stages I and II disease. A reduction in the symptomatic period was also noted over this time, and a direct relationship was found between the duration of symptoms and tumour size, nodal status and overall stage of disease. A subsequent comparison with the staging data from 40 women with breast cancer detected at a breast screening clinic (1985-87) shows that significant further advances in the earlier diagnosis of breast cancer can be achieved. Mammographic breast screening centres represent the best-known means of early breast cancer detection, and thus may hold the key to reducing breast cancer mortality.

Adult

The separation of peptide hormone diastereoisomers by reverse phase high pressure liquid chromatography. Factors affecting separation of oxytocin and its diastereoisomers--structural implications.

Experimental conditions and parameters involved in high performance liquid chromatography (HPLC) separations of the peptide hormone oxytocin and seven of its diastereoisomers, namely [1-hemi-D-cystine]-, [2-D-tyrosine]-, [4-D-glutamine]-, [5-D-asparagine]-, [6-hemi-D-cystine-], [7-D-proline]-, and [8-D-leucine]-oxytocin, on reverse phase columns were investigated. The effects of solvent, pH, and salt concentration were studied. Using the solvent systems 10% tetrahydrofuran-ammonium acetate buffer or 18% acetonitrile-ammonium acetate buffer and the muBondapak C18 support, oxytocin was separated from each of its diastereoisomers under all conditions studied, but the order of elution of diastereoisomers was highly dependent on solvent and to a lesser extent on pH. Separations of the hormone and its diastereoisomers on reverse phase HPLC and on classical partition chromatography on Sephadex G-25 were compared. The results are discussed in terms of the interactions of the solute with the reverse phase column and the solvent system. Implications of these findings in terms of the different solution conformations of the peptides are discussed.

Amino Acid Sequence

Forceps delivery.

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Extraction, Obstetrical