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R Kattermann

Publications and source records attributed to R Kattermann.

At least 37 records · Page 2Linked to original sources
PubMed1989

Improved method for enzymic determination of cholesterol in lipoproteins separated by electrophoresis on thin layer agarose gels.

The cholesterol of lipoproteins, separated electrophoretically on thin layer agarose films, is visualised and quantitated by incubating the gels in an enzymic reagent containing cholesterol esterase and cholesterol dehydrogenase. The individual fractions are quantitated by scanning densitometry. No sample pretreatment is necessary. All major fractions are detected readily. The accuracy of the determination is similar to that of ultracentrifugation. On average, imprecision is 3.1% for beta-, 7.0% for pre beta-, and 4.8% for alpha-lipoprotein cholesterol. Concentration and colour development are linear up to 8 mmol/l cholesterol in a given lipoprotein fraction. The results from the direct enzymic procedure for beta-, pre beta- and alpha-lipoprotein cholesterol are compared with those from quantitative lipoprotein electrophoresis after precipitation with phosphotungstic acid and bivalent cations and with those from different precipitation methods using dextran sulphate and polyethylene glycol. The new method has several advantages: high specificity; lack of dependence on the actual composition of the lipoproteins; lack of interference from coprecipitated proteins in the gel, e.g. fibrinogen or paraproteins; and insensitivity to lipolysis and high free fatty acid concentrations caused by heparin application or ageing of the specimen (at least for alpha-lipoprotein cholesterol quantitation). In its convenience and simplicity of operation, and the simple calculation of results, the method is similar to standard protein electrophoresis. The proposed method is therefore suggested as a standard method for elucidating lipoprotein disorders.

Cholesterol↗
PubMed1989

Enzymatic determination of lipids in human bile without bilirubin interference: reliable assessment of the cholesterol saturation index (CSI).

We describe a simple and rapid, but nevertheless precise and accurate method for the enzymatic determination of the main lipid constituents in human bile. Interfering bile pigments, especially bilirubin are eliminated by the use of aminopropyl bonded phase columns ("Bond-Elut") prior to the enzymatic measurement of cholesterol and lecithin. Intra-assay imprecision was between 3.1 and 4.9% CV, while the inter-assay figures were rather higher at 4.6 to 7.5% CV. Recoveries of bile salts, lecithin and cholesterol were between 94 and 103%. In contrast, the direct enzymatic determination in native bile produces falsely low results: lecithin from 5 to 20%, cholesterol from 25 to 40% of the true value. The results of both enzymatic methods correlated well with commonly accepted procedures for phospholipid and cholesterol determination. When compared with methods of bile lipid analysis involving solvent extraction, the column separation followed by enzymatic determination has the advantage of being simpler and less time consuming, without need of high-cost equipment, e.g. gas chromatography.

Alcohol Oxidoreductases↗
PubMed1989

[Risk indicators of urinary calculus formation: value of oxalate and citrate excretion in comparison with the oxalate tolerance value].

Several methods for the measurement of crystallization conditions in urine, the so-called whole urine systems, have recently been of considerable interest in urolithiasis research. The diagnostic accuracy of the oxalate tolerance value (OTV) was therefore compared with the daily excretion of oxalate and citrate in normal persons and patients with urinary calculi. With the aid of the oxalate/citrate ratio, 77% of the patients could be classified correctly. After standardization of the experimental conditions (24-h urine sample, constant pH value, consideration of endogenous oxalate) we succeeded in correctly classifying 82% of patients using the OTV. These results favour the introduction of the OTV as a clinical chemical tool for the follow-up of patients with urinary calculi and for the screening of normal persons at risk.

Adult↗
PubMed1988

A specific method for the direct determination of lipoprotein cholesterol in electrophoretic patterns.

Lipoproteins are separated electrophoretically and cholesterol is visualised with an enzymic reagent specific for cholesterol in which the gels are incubated. Quantitation of the individual fractions is accomplished by scanning densitometry. No sample pretreatment is necessary. All major fractions are detected readily. Accuracy agrees favorably with results from the ultracentrifugation. On the average, imprecision is 3.1% for beta-, 6.9% for prebeta-, and 5.2% for alpha-lipoprotein cholesterol. Concentration and color development are linear up to 8 mmol/l cholesterol in a given lipoprotein fraction. The results of the direct enzymic procedure for beta-, prebeta- and alpha-lipoprotein cholesterol are compared to the quantitative lipoprotein electrophoresis after precipitation with phosphotungstic acid and bivalent cations.

Cholesterol↗
PubMed1988

Investigation of the performance of the ES 600 Enzymun-Test system. A multicentre study.

The ES 600 sample-selective multibatch analyser was subjected to a multicentre evaluation in six laboratories in accordance with ECCLS guide-lines. During the 3-month trial, five Enzymun-Test diagnostics (T4, TBG, Digoxin, CEA and TSH)1) were measured at 25 degrees C. The study yielded the following results: 1. The within-series and between-series precision were very good, with mean CV's of approx. 3% and 7% respectively. 2. Recovery of the target values for three control sera was in the range +/- 5%. 3. A trend in measurements did not occur in any of the methods investigated (for series of over 240 determinations). 4. Comparison of the results with those obtained on the ES 22 Enzymun-Test system showed good agreement. 5. Within the measuring range defined by the standards, no deviations could be ascertained upon dilution of the samples. 6. Total carry-over in the instrument was below 0.05%. From studies with instruments from the first production series, it became evident that modifications were necessary to improve the reliability. A follow-up measuring programme confirmed a clear improvement in reliability and a reduction in the imprecision, particularly for results from series to series.

Carcinoembryonic Antigen↗
PubMed1985

Acetate formation after short-term ethanol administration in man.

The effect of an acute oral load of 0.5 g ethanol/kg body weight was studied in a group of 10 healthy male and one of 10 healthy female individuals. The following parameters were measured in the blood between 0 and 7 h after the start of the experiment: ethanol, acetate, glucose, free fatty acids, free glycerol, lactate, pyruvate, 3-hydroxybutyrate, acetoacetate. While the elimination of ethanol followed zero-order kinetics between 2 and 5 h, a steady-state concentration of 0.4 to 0.6 mM acetate in the serum was observed during the same time interval. Concomitantly, a significant decrease of free fatty acid and free glycerol concentrations was observed.

Acetaldehyde↗
PubMed1985

Enzymatic determination of acetate in serum.

With 100 microliters sample volume or less acetate can be measured accurately in serum without deproteinization by a coupled enzymatic reaction in a spectrophotometer. The reaction is linear from 250 to 5000 mumol/l acetate with a detection limit of 25 mumol/l. The imprecision from day to day was found to be 2.82% using frozen human pool serum with added sodium acetate. The method was found reliable in routine use, e.g. in man.

Acetate-CoA Ligase↗
PubMed1984

Multicentre study of a new enzymatic method of cholesterol determination.

A new enzymatic method for the determination of cholesterol in serum and plasma was evaluated in 8 separate laboratories in comparison with routine and reference methods. Investigation of the analytical reliability in the 2-26 mmol/l measurement range showed the following results: At the set reading points (10 min at 25 degrees C and 5 min at 37 degrees C) the reaction shows complete substrate conversion. The colour complex is stable over a period of 60 min. The response to cholesterol is linear up to 26 mmol/l. Precision within the series was 0.6-2.8% in 20 determinations (coefficient of variation). Day to day precision was 0.5-3.3% in triple determinations of 10 days (coefficient of variation). Accuracy was studied with 2 samples (assigned value: 3.52 and 6.70 mmol/l respectively). In the case of sample 1 the mean for the 8 laboratories was 3.44, with a median of 3.44; for sample 2 the values were 6.68 and 6.72. The results demonstrate an excellent transferability. In comparison with other enzymatic procedures, the values found with the new test were 5-10% higher; these results agree at all concentration ranges with the reference methods of Abell & Kendall and with those from mass spectrometry.

Cholesterol↗
PubMed1984

[Walter Siegried Loewe (1884-1963). His contribution to the analysis, biology and pharmacology of sex hormones].

Walter Siegfried Loewe was born on August 19, 1884, in Fürth, Bavaria. The centenary of his birth should be of interest to pharmacologists, endocrinologists and clinical chemists, alike. In this short review an attempt has been made to describe the contributions of Loewe and his coworkers to the biochemistry and analysis of the sex hormones. Loewe began his research on dose effect-response of ovarian extracts at the University of Dorpat, Estonia. By quantification of the Allen-Doisy-test, Loewe was the first to succeed in measuring oestrogens in human blood and urine. Further scientific research was focussed on the content and the local effects of oestrogens within the placenta. In the same time, Loewe and his coworker Voss developed the first, specific bioassay for the male hormone. It was based on the histological repair of the epithelium of the seminal vesicles in castrated mice, brought about by the injection of testicle extracts. With the aid of this so-called "cytological regeneration test" Loewe was able to isolate and characterize androgens from different biological sources. The male hormone was called "androkinin", and in 1928 Loewe reported the occurrence of androkinin in human male urine and its separation from oestrogens in the same material. On the basis of the early mitogenic effect of androgens the bioassay of Loewe & Voss was further improved, serving as a fundamental prerequisite for the isolation and chemical charcterization of the androgens in the early thirties. Loewe who had held the chair of pharmacology at Dorpat since 1921, came to Mannheim in 1928 as head of the Main Laboratory of the Municipal Hospital. In 1933 he was forced to emigrate, went first to Cornell-University, New York and later to the Department of Pharmacology at the University of Utah. In 1948 he became an honorary member of the German Pharmacological Society and in 1960 of the German Society of Endocrinology. Three years later, on August 24, 1963 at Salt Lake City, Loewe died at the age of 79 years.

Animals↗
PubMed1983

[Candidate selected method for the enzymatic determination of total cholesterol in serum].

An enzymatic method is described for the determination of total cholesterol in serum using a single aqueous reagent which can easily be prepared from commercial substrates and enzymes. The determination is carried out manually, the resulting stable chromogen is measured at a wavelength of 500-550 nm. The cholesterol concentration may be calculated either using a primary cholesterol standard or a constant factor for a given wavelength. The reliability of the method is reported: Data for the imprecision are given on the basis of a survey in 3 laboratories, the accuracy is established by comparison with a definitive and a reference method. Analytical and biological interferances are briefly discussed and results with this enzymatic method are reported concerning the reference values for serum cholesterol.

Cholesterol↗
PubMed1982

[Diabur-Test 5000 - a new test strip for urinary sugar control in diabetic patients (author's transl)].

Diabur-test 5000, a new test strip for estimation of urinary glucose, was compared with the hexokinase glucose-6-phosphate dehydrogenase method in more than 2500 urine samples. By combination of two test ranges glucose concentrations of up to 5% can be detected by the strip test. After a reading time of 2 minutes, very precise estimation of urinary glucose is possible in eight steps from negative to 5%. False estimations of more than one color step virtually do not occur. Ketone bodies, salicylic acid and several antibiotics do not influence the test strip. Ascorbic acid shows a slight influence only in concentrations above 40 mg/dl. This influence disappears with glucose concentrations of more than 0.5%. Good correlation with the reference method, wide range of readings and simple handling make the test strip suited for the laboratory and particularly for self control of diabetic patients.

Anti-Bacterial Agents↗
PubMed1982

Studies on the mechanism of the increase in serum alkaline phosphatase activity in cholestasis: significance of the hepatic bile acid concentration for the leakage of alkaline phosphatase from rat liver.

In experimental bile obstruction the serum activities of the membrane-bound liver enzymes, alkaline phosphatase, 5'-nucleotidase and gamma-glutamyltransferase are greatly increased, whereas in the liver only the alkaline phosphatase activity is elevated. After partial hepatectomy or tetrachloride poisoning the alkaline phosphatase activity in the regenerating live is increased to the same extent as in cholestasis without an accompanying elevation in serum activity. The following results support the hypothesis of a bile salt-mediated solubilization of membrane-bound enzymes in cholestatic liver: (1) 30 min after bile duct ligation the total bile acids in the liver were increased 5-fold, 2 h later as much as 10-fold. After 1 day, the bile acid concentration was still 4 times above normal. (2) Isolated plasma membranes from normal and obstructed livers were incubated in vitro with increasing amounts of tri- and dihydroxycholanic acids. At a final concentration of 1 mmol/l taurochenodeoxycholate significant amounts of membrane-bound enzymes were released into the 12,000-g supernatant. (3) In the regenerating liver, where tissue phsophatase activity was high and serum phosphatase activity unchanged, the bile salt concentration was not increased.

Alkaline Phosphatase↗
PubMed1982

[Carbohydrate content of lipoproteins after sequential precipitation with phosphotungstate magnesium chloride].

A method is described for rapid determination of protein-bound carbohydrates in human lipoproteins. The method is based on a successive precipitation of lipoproteins with sodium phosphotungstate and magnesium chloride. After purification of the separated lipoproteins by a twofold reprecipitation, a colorimetric determination of hexoses, hexosamines and N-acetylneuraminic acid (sialic acid) is performed. The coefficients of variation in the series are between 3.2% and 7.3%. The results for lipoprotein-bound carbohydrates after precipitation are compared with the corresponding values after separation by ultracentrifugation. The concentrations of hexoses, hexosamines and N-acetylneuraminic acid in the 3 lipoprotein classes VLDL, LDL and HDL of control persons are reported.

Carbohydrates↗