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Biomedical subjects

A Uldall

Publications and source records attributed to A Uldall.

45 records · Page 3Linked to original sources
PubMed1980

Prothrombin time standardization and temperature problems.

The reaction temperature is crucial for enzymatic reactions. Difficulties in controlling the temperature in the tilt test tube technique for the prothrombin time test are illustrated. An improved detailed description of the technique is suggested for standardization purposes. Mixing of the specimen with the reagent should be done in the water bath. The test tubes should be immersed deeply into the bath. Recording of the temperature in the reaction mixture is recommended. When using plastic test tubes the temperature problems may be greater than with glass test tubes. Some heat denaturation of coagulation enzymes may take place at 37 degrees C. Lowering the temperature of the reaction to 30 degrees C and perhaps photometric recording of the coagulation should be included in a suggested future optimized reference method.

Evaluation Studies as Topic↗
PubMed1980

Present analytical quality in the Nordic clinical chemistry laboratories.

An introductory review is given of the discussion in the Nordic countries on the definition, aim, and optimal organization of quality control. Published and unpublished Scandinavian works have been reviewed and commented under the following headlines: common chemical analyses, enzyme analyses, serum and plasma protein analyses, hormone analyses, drug analyses, hematological tests, and urine analyses. It is concluded that methods for calculating medical standards of analytical quality in clinical chemistry form the logical background for the design of an optimal quality control system, which will guarantee that analytical results well have a specified probability of satisfying the medical requirements.

Chemistry Techniques, Analytical↗
PubMed1980

Stable reagents and a suitable routine procedure for the cystinuria test.

A simplification of the borohydride-cyanonitrosylferrate (nitroprusside) test for cystine in urine is described. The borohydride reagent is stabilised by cooling and by using pure components. Octanol-1 is used to reduce foaming. The cyanonitrosylferrate reagent is stabilised by sulphite and by storage at -80 degrees C. Compared with previous methods, it is possible to use higher (more than 4 times) dilutions of urine. An aqueous cystine solution may be used as a standard for visual evaluation; for the previous methods there is no well defined material for standardisation. The described procedure is intended for visual evaluation; the method is also suitable for quantitation by photometry.

Borohydrides↗
PubMed1976

Improvements and simplifications of the ozonolysis-Schiff staining method for plasma lipoproteins on cellulose acetate.

Modifications of the ozonolysis and Schiff staining of plasma lipoproteins reduce 11 pre-spectrometric steps to 3. Picrate denaturation of the lipoproteins and absorption spectrometry directly on the wet opaque membrane increase the sensitivity; the volume of sub-specimen needed per length of application site is reduced from 0.7 to 0.1 mul/mm. Reasonably good proportionality between the total lipoprotein concentration and the spectrometric findings are obtained. Two specimens were obtained at an interval of 8-13 days from each of 10 patients; for the arbitrary substance fraction of alpha-, prebeta-, and beta-lipoproteins in plasma the between-series intra-individual standard deviations were 0.021, 0.023 and 0.032 respectively.

Electrophoresis, Cellulose Acetate↗
PubMed1976

The composition of gallstones from geriatric patients. Methods for the determination of cholesterol and of black substances in gallstones.

78 female and 31 male Danish gallstone cases found by autopsy were studied. The mass of the gallstone(s) from each patient was recorded and the stones were ground. The content of cholesterol in the mixed material from each patient was determined, using the Liebermann-Burchard reaction. The ratio Gallstone(s) ash-mass/Gallstone(s)-mass was determined, and where this ratio exceeded 0.10, calcium and phosphate determinations were carried out. Subjective description of the stones as 'mixed stones' or 'pigment stones' was substituted by visual comparison of the ground gallstones with a 'grey scale' (black was given the highest value). The values of this quantity and the ash values generally increased with a decreasing content of cholesterol. The content of cholesterol in the gallstones increased with increasing stone mass. The chemical composition of gallstones found by surgery seems to differ from that of gallstones found by autopsy.

Aged↗