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Biomedical subjects

P Vestergaard

Publications and source records attributed to P Vestergaard.

At least 127 records · Page 7Linked to original sources

Multi-column chromatography of urinary 17-ox osteroids as their 2,4-dinitrophenylhdrazones.

The use of 2,4-dinitrophenylhydrazones in the multi-column chromatography of 17-oxosteroids from urinary extracts has been possible on mixed columns of alumina and silica gel. Preliminary results indicate agreement with values obtained using the Zimmermann reaction. The hydrazones have the advantage of color stability, when compared with the Zimmermann reaction, and the analysis is simpler and cheaper to perform.

17-Ketosteroids

The multicuvette general analytical system for combined multi-column chromatography and high capacity single substance and group analyses and its application to steroid analyses.

A description is given of the development of a general analytical system for both single and group analyses and for analyses of profiles of compounds after multi-column liquid/liquid and liquid/solid chromatography. Common for both branches of the system is a computerized quantitation system built around a multi-compartmented cuvette. The system is compared with other high capacity systems for biochemical analyses. Special attention is given to the application of the system to the analysis of urinary steroids, both individual and as groups, with a comparison with similar methology using other techniques.

Autoanalysis

General methodology for the estimation of common neutral urinary steroids by multi-columin liquid chromatography.

A method is described for the estimation of common neutral urinary steroids by multi-column liquid chromatography. Hydrolysis is performed in two steps: enzymatically, using beta-glucuronidase, followed by solvolysis. Initial short column chromatography separates the neutral steroids into three fractions according to polarity: 17-oxosteroids, corticosteriods less polar than cortolones, and cortolones and cortols. The cortolone, cortol fraction is oxidized and the different steroid groups are chromatographed on capillary aluminum oxide and silica gel columns. A computerized, spectrophotometric system is used for the quantitation procedure.

17-Ketosteroids

The hydrolysis of conjugated neutral steroids in urine.

Complete hydrolysis of known conjugates of neutral steroids in urine requires a combination of solvolysis and enzymatic hydrolysis. Procedures are established for optimal yield in the enzymatic part of the hydrolysis using different preparations of beta-glucuronidase. The effect of temperature and the use of conjugate extraction in the hydrolytic procedure is explored. It is stressed that relatively high concentrations of enzyme are necessary to insure full hydrolysis of a few conjugates that are particularly difficult to split by enzymatic hydrolysis.

Animals

Factors affecting the excretion of common neutral steroids in urine.

After a brief summary of the biosynthesis, production rates, metabolism and elimination of the pertinent adrenocortical and gonadal precursors for the common urinary neutral steroids, a survey is presented of the general, disease related and hormonal factors that can affect the excretion of neutral steroids in urine.

Adrenal Cortex Hormones

Relationship between steroid excretion patterns and breast cancer incidence in Israeli women of various origins.

A nationwide study of the steroid excretion patterns in postmenopausal Israeli migrant women demonstrated differences between high- and low-risk groups for breast cancer in the following variables: age at first parturition, number of pregnancies, number of live births, height, and weight. The direction of the differnces was in line with those observed for breast cancer patients. The groups also differed in the exretion of estriol, 17-ketosteroids, and allotetrahydrocortisol. Multiple regression analysis revealed that the exretion of estriol was significantly lower in population groups in whom breast cancer incidence was high. Possibly this trend--which has also been observed in adolescent and premenopausal women--reflected environmental influences on peripheral estrogen metabolism.

17-Ketosteroids

Total and subtotal colonoscopy with short instrument and without fluoroscopy.

The technique and results of 111 consecutive colonoscopies with a short colonoscope without the use of X-ray screening are reviewed. The caecum could be reached in 44 percent of the cases. No complications occurred. The great clinical value of the procedure is shown by the following findings:X-ray-negative lesions--including 2 cases of carcinoma--were found in 35 percent of the cases, radiologically demonstrated lesions could be defined more precisely in 18 percent, and the presence of colonic lesions could be ruled out in 11 percent in spite of equivocal X-ray findings. It is concluded that many more centres ought to take up the procedure, which offers the prospect of significantly reducing suffering and death from colonic disease.

Adult

Lithium treatment of Huntington's chorea. A placebo-controlled clinical trial.

The therapeutic effect of lithium in Huntington's chorea was tested in six patients through a double-blind cross-over comparison of lithium and placebo, each administered for 6 weeks. Four of the patients received neuroleptic drugs at the same time. Lithium and placebo periods did not differ as regards motor skills, hyperkinesias, or total ward situation, all rated quantitatively with the use of scales. Lithium does not seem to be of therapeutic value in Huntington's chorea.

Adult

Computerized multicuvette system for single substance and group analysis and for the chromatographic isolation and quantitation of compounds in complex mixtures.

A new computer-interfaced system of general applicability in the clinical laboratory has been built. The system is constructed around a new type multicuvette. Quantitation is currently by spectrophotometry and is on-line, with use of a mini-computer with output going to an electrostatic printer/plotter. The system can be used for single-substance batch analyses, for group analyses, and for the estimation of profiles of compounds after preliminary high-resolution liquid chromatography tailored to interface with the multicuvette.

17-Ketosteroids