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Biomedical subjects

K Rubach

Publications and source records attributed to K Rubach.

12 recordsLinked to original sources
PubMed2002

Determination of tocopherols, tocopherolquinones and tocopherolhydroquinones by gas chromatography-mass spectrometry and preseparation with lipophilic gel chromatography.

Lipophilic gel chromatography using Sephadex LH-20 helps in separating alpha-, beta- + -gamma, and delta-tocopherol and also in separation of their oxidation products e.g. the tocopherolquinones or other oxidation products. This preseparation can help to overcome analytical problems due to the complexity of synthesis mixtures of tocopherol oxidation procedures as well as in separation of complex physiological matrices. Determination of the preseparated tocopherols, tocopherolquinonesand tocopherolhydroquinones can then be achieved by means of GC-MS measurement of the free substances or their trimethylsilyl derivatives.

Chromatography, Gel↗
PubMed1995

Determination of chloramphenicol in muscle, liver, kidney and urine of pigs by means of immunoaffinity chromatography and gas chromatography with electron-capture detection.

A rapid and specific clean-up procedure based on immunoaffinity chromatography (IAC) with polyclonal antibodies for the gas chromatographic determination with electron-capture detection of chloramphenicol in pig muscle tissue, organs and urine is described. A commercially available IAC material was used for the analysis. A decrease in the capacity of the column after being used more than 100 times was observed. Mean recoveries were 69, 54, 62 and 95% for spiked pig muscle tissue, liver, kidney and urine, respectively. The limit of detection was 0.2 micrograms/kg for muscle tissue, 2.0 micrograms/kg for liver and kidney and 0.4 micrograms/kg for urine.

Animals↗
PubMed1986

[Isolation of antibodies against soy protein from the eggs of immunized laying hens].

The authors report on their experiences with immunization of laying hens with alpha-, alpha'- and beta-conglycinin, and on the isolation of specific antibodies from the yolks. Activity and specificity of the immunoglobulins were tested by an enzyme-linked immuno sorbent assay (ELISA). This method of antibody production proved to be very convenient, especially in regard to the high yield of antibodies and the easy handling of the animals. The necessity of using specific antisera for quantitative immunoassays is pointed out.

Animals↗
PubMed1980

[Isotachophoretic determination of preservatives (author's transl)].

The preservatives sorbic acid, benzoic acid, methyl-, ethyl-, propylester of p-hydroxybenzoic acid and propionic acid can be determined quantitatively in one step by isotachophoretic separation based on the different electrophoretic mobilities of these compounds. The determination involves a direct extraction step in the so called Extrelut-columns, where the preservatives are separated from the food sample, mainly from the lipid phase. The whole analysis procedure is short and recoveries for the preservatives in the samples tested are very good. There is no interference by other substances and the range of concentrations for which a determination is possible is large and encompasses virtually all concentrations used in commercial practices.

Benzoates↗
PubMedDate not supplied

[Adrenocortical function in myasthenia pseudoparalytica].

In a group of 31 women with myasthenia the urinary excretion of 17-ketosteroids and their fractions (11-deoxy-17-ketosteroids, dehydroisoandrosterone) and 17-hydroxycorticosterone were determined. A statistically significant decrease was observed in the excretion of these substances. Besides that, the plasma cortisol level was determined in these patients and the results obtained in the whole group were at the lower normal range of the laboratory and in 40% of cases they were significantly lower (p less than 0.01). The obtained results may suggest that adrenocortical hypofunction exists in many cases of myasthenia. The pertinent literature is reviewed.

17-Hydroxycorticosteroids↗