PubMed Health⌕ Search

Biomedical subjects

G Gübitz

Publications and source records attributed to G Gübitz.

27 records · Page 2Linked to original sources
PubMed1996

Precipitation flow injection immunoassay for human immunoglobulin G.

The development of a precipitation flow injection immunoassay is described. This approach is based on the immunoprecipitin reaction, whereby the precipitate formed by binding of the sample antigen (HIgG) to fluorescein-labelled antibodies is retained on a filter built in on-line in a flow-injection system. After dissolving the precipitate with sodium hydroxide solution the liberation of fluorescein-labelled antibodies results in a fluorescence signal that is directly proportional to the concentration of HIgG. The instrumental set-up is very simple and fully automated. One assay cycle takes about 10 min. The RSD ranged between 1 and 3%, depending on concentration. The detection limit was about 140 fmol. The recovery from spiked serum samples was between 96 and 102%.

Automation↗
PubMed1996

Systemic application of cysteine-2:1-crotonal adduct for pharmacokinetic studies of tumor models in rats and mice.

A selective cytostatic effect is demonstrated for systemic application of the Michael adduct of crotonal (CAS 4170-30-3) with cysteine (CAS 52-90-4). As in earlier studies, our initial model was the Ehrlich ascites tumor (EAT) in mouse. Tablets containing 150 mg of the substance were implanted subcutaneously. Substance concentrations were found to be higher in the ascites fluid than in the blood. A better model, the Walker-256 carcinosarcoma (Wa256), was used subsequently. Due to its rapid growth, results are available promptly. The EAT results were confirmed and it was also found that there are higher substance concentrations in the cytoplasma of Wa-256 cells than in cells in neighboring liver tissue. During the period when substance was being liberated from the tablet, substance concentration in the blood was constant, and considerably lower than in ascites fluid or cytoplasma. This confirms that cysteine-2:1-crotonal adduct can be applied systemically from a subcutaneous depot to a model tumor in a cytostatic concentration.

Animals↗
PubMed1985

[Fluorodensitometric determination of cytostatic acting Michael-adducts of alpha, beta-unsaturated aldehydes in biologic material].

Alpha, beta-unsaturated aldehydes produce a selective cytostatic effect on tumor cells. By the formation of Michael adducts with cysteine, toxicity can be greatly reduced without impairing cytostatic effectiveness. To further enhance the selectivity of the toxic effect, it is necessary to be able to follow the agent's kinetics in the animal body. Among the analytic methods developed to this end, this paper represents the fluorescence derivatisation as a sensitive method for the determination of the Michael adducts of alpha, beta-unsaturated aldehydes in pharmaceutical preparations and in biological material. It is based on the reaction of the carbonyl groups with dansyl hydrazine. Determination is carried out by a combination of thin-layer chromatography with subsequent fluorodensitometric evaluation. The detection limit in blood is about 20 micrograms/ml. The relative standard deviation of this procedure ranges between 3 and 7%.

Aldehydes↗
PubMed1976

Fluorescence densitometric method for the determination of gluconic and lactobionic acids ("sugar acids") in pharmaceutical preparations.

An in situ fluorimetric method has been developed for the quantitation of gluconic and lactobionic acids and their salts in tablet formulations. The method is based on glycol cleavage with lead tetraacetate followed by treatment with dichlorofluorescein. Calcium gluconate and lactobionate were determined in Calcium-Sandoz and Ca-C 1000 Sandoz effervescent tablets. The reproducibility corresponded to relative standard deviations between 0.7 and 3.5% (usually below 2%). Detection limits of 0.2 mug per spot can be obtained. Interfering compounds such as citric acid, sugars and ascorbic acid can be separated from the "sugar acids". The linearity of the calibration graphs between 0.5 and 5 mug per spot is satisfactory (r = 0.994-0.999). The method is simple and could be applied to the routine analysis of suitable pharmaceutical formulations. Other compounds with glycol structures should also be adaptable to this technique.

Chromatography, Thin Layer↗
PubMedDate not supplied

Chiral separation by chromatographic and electromigration techniques. A review.

This review gives a survey of different chiral separation principles and their use in high-performance liquid chromatography (HPLC), gas chromatography (GC), supercritical fluid chromatography (SFC), thin-layer chromatography (TLC), capillary electrophoresis (CE) and capillary electrochromatography (CEC) highlighting new developments and innovative techniques. The mechanisms of the different separation principles are briefly discussed and some selected applications are shown.

Chromatography↗