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Biomedical subjects

I R Kupke

Publications and source records attributed to I R Kupke.

At least 19 recordsLinked to original sources
PubMed1986

Sequential microultracentrifugation of lipoproteins in 100 microliters of serum.

A method is described for sequential separation of high density, very low density, and low density lipoproteins (HDL, VLDL, and LDL, respectively) from 100 microliters of serum, using an air-driven ultracentrifuge (Airfuge, Beckman). Cesium chloride was used for density adjustment. Precision-within-series (coefficient or variation) depended on the cholesterol concentration in the lipoprotein fractions, greater than 1 mmol/l, less than 2.3%. Recovery within-series was nearly 100%. The results (mmol/l) correlate well with those from an electrophoretic-enzymatic procedure (alpha-HDL: 1.49 +/- 0.34 vs. 1.48 +/- 0.33, r = 0.949; pre-beta-VLDL: 0.58 +/- 0.42 vs. 0.59 +/- 0.45, r = 0.975; beta-LDL: 3.11 +/- 0.93 vs. 3.07 +/- 0.88, r = 0.990; n = 48). Recovery of lipoprotein cholesterol from this group was 99.2 +/- 4.2%. A combination of ultracentrifugation with high-performance thin-layer chromatography for determination of lipoprotein-lipid profiles was achieved with recoveries of 98-101%, as evaluated from a group of healthy men (n = 31) and women (n = 38). The entire procedure is, therefore, suitable for compositional studies on lipoproteins from small serum samples. In particular, capillary serum from children of all ages, even from premature neonates, is quite adequate.

Animals↗
PubMed1985

On the advantage of screening kindergarten children for atherogenesis-related risk indicators.

On the basis of our practical experience we can recommend screening of young children outside the clinic. Our methodology has proven to be appropriate for this purpose. Among young children, three groups are easily accessible: Newborns - since delivery occurs mostly in a clinic; infants up to one year - since these children are provided with basic medical care, and kindergarten children. According to our experience, kindergartens are favorable places for screening children because many children are together in one place. Children of this age can be easily motivated to cooperate during the examination, and since they stay in the kindergartens for a considerable period of the day, they only can be guided by nurses who can provide positive motivation for educational programs. As an additional advantage, the cooperation between nurses and parents, as well as positive influence on the parents, by the nurses might be taken into account. In this context, nurses must be regarded as key persons for strategies when considering life-style changes. Identifying children at risk at this early age could shorten the pathogenetic period and increase the chance for regression of the atherosclerotic disease process. Furthermore, children of this age are willing to learn and to change their habits. There is also a possibility that children may implant in their families experiences and information obtained in the kindergartens. Such parents might be more open to advice from kindergarten personnel, and thus also profit for themselves. An additional and valuable advantage of screening kindergarten children is the possibility of detecting first-degree relatives at risk before clinical manifestation of the disease, thereby having a good chance for successful intervention.

Arteriosclerosis↗
PubMed1983

Early indicators for the risk of atherogenesis. A field test of a new methodology on kindergarten children in Düsseldorf.

Parameters related to the risk of atherogenesis in adults were investigated in kindergarten children living in an industrial city. Height, weight and blood pressure were measured and capillary blood obtained. This study is a field test of methods for the analysis of 11 metabolic variables in capillary serum [glucose (GLUC), uric acid (UA), total, free and esterified cholesterol (TC, C, CE), triacylglycerols (TG), phosphatidylethanolamine (PE), phosphatidylcholine (PC); beta-, pre-beta- and alpha-lipoproteins (LPs)]. For lipid and LP analysis, new micro- and ultramicroprocedures were used, which have proved to be adequate for large-scale studies outside the clinic, including young children. Among 497 German children, a reference group, an overweight group and a socially underprivileged group were distinguished. In the reference group, several sub-groups with parameters lying in the tails of the concentration distributions were considered separately, thus providing specific metabolic patterns for these groups and, also, for any individual child. The children in the overweight group exhibited significantly reduced TC and beta-LP levels. In socially underprivileged children with anthropometric data within the normal range, a reduction of several blood constituents was seen: GLUC, TG, TC, PC, pre-beta- and alpha-LP; the PC: PE ratio was diminished. The beta: alpha-LP ratio in these children was moderately increased. This effect was more pronounced in growth-retarded children, who also showed negative correlation of TG: alpha-LP.

Arteriosclerosis↗
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↗
PubMed1981

On the composition of capillary and venous blood serum.

The concentrations of various clinical-chemical substances in the capillary and venous blood serum of apparently healthy adults (20-30 yr) were examined in the fasting state. Total protein, bilirubin, calcium, sodium and chloride concentrations were significantly lower (less than or equal to 5%) in capillary than in venous serum. In non-hemolytic capillary sera, the concentration of potassium was nearly the same as in venous samples. Inorganic phosphorus and urea concentrations were identical in both specimens. There was a tendency for glucose concentrations to be higher in capillary than in venous serum. It is concluded that capillary and venous blood serum can be used interchangeably only for certain purposes. It should be emphasized that these results are valid for apparently healthy adults in the fasting state; other population samples remain to be investigated.

Adult↗
PubMed1981

Studies on the hygiene of drinking water for laboratory animals. 2. Clinical and biochemical studies in rats and rabbits during long-term provision of acidified drinking water.

The reaction of rats and rabbits to long-term application of acidified drinking water (pH 2.3-2.5) was observed over a 7-months period. The following parameters were studied: growth curves initiated at weaning, haematology, blood glucose, total serum protein, creatinine, inorganic phosphate, sodium, potassium, calcium, alkaline phosphatase, creatinine kinase, serum glutamate oxalacetate transaminase, and serum glutamate pyruvate transaminase in serum as well as the acid-base status in arterial blood; in addition in rabbits gamma-glutamyl transferase and lactate dehydrogenase were examined in the serum. No significant changes were seen in comparison to the control groups.

Animals↗
PubMed1980

[Creatine kinase "NAC-activated": reference values for children (author's transl)].

Reference values for 327 children aged between 1 day and 15 years are given for the revised standard method for the determination of serum creatine kinase (CK) activity by activation with N-acetylcysteine (NAC). No sex-dependence could be observed, but CK activity was found to vary markedly with age. The following values are suggested as upper limits of the reference ranges for measurements at 25 degrees C: neonates: 1-3 days: less than or equal to 370 U/l, 4-10 days: less than or equal to 200 U/l, 11-31 days: less than or equal to 100 U/l; children (2 months-15 years): less than or equal to 90 U/l.

Acetylcysteine↗
PubMed1980

New microprocedures for lipid and lipoprotein (LP) analysis: examination of apparently healthy children and young adults.

New microprocedures for the determination of lipid concentrations in serum and LPs of capillary blood were applied to the examination of various population groups (German and Japanese kindergarten children as well as young men and women of Duesseldorf). Our data were largely consistent with those reported by other authors. This result together with the analytical reliability and practical simplicity of the new procedures has led us to conclude that our methodology is suitable for large-scale studies on disorders in lipid and LP metabolism, e.g. in atherogenesis.

Adult↗
PubMed1979

Differences in lipid and lipoprotein concentrations of capillary and venous blood samples.

The concentrations of lipids and lipoproteins measured in capillary blood serum taken from young adults were significantly lower than in venous blood, although they correlated satisfactorily. These differences may reflect differences in the morphological and hemodynamic conditions existing either in large veins or in the peripheral circulatory system. It was concluded that venous and capillary blood serum cannot be used interchangeably for these estimations.

Adult↗
PubMed1979

Enzymatic microdetermination of plasma lipoprotein cholesterol without ultracentrifugation.

The lipoprotein fractions of 15 microliter capillary plasma were separated by electrophoresis on agarose gel. The samples were dried, dissolved in HCl, and neutralized with a saturated Tris solution producing a Tri-buffer system at pH 7. This improvement of sample neutralizing made the system highly suitable for enzymatic determination of cholesterol. The kinetic properties and linear range of this reaction system, the precision (coefficient of variation 1--3%) and the recovery of cholesterol (100%) were found to be optimal.

Cholesterol↗
PubMed1979

Comparison of two micromethods for determination of lipoprotein cholesterol in plasma.

We compared the results obtained by a micromethod for the determination of plasma lipoprotein cholesterol, in which electrophoresis is used to separate the lipoprotein fractions (beta-, pre-beta-, and alpha-lipoproteins), with those determinations with ultracentrifugation (low-density, very-low-density, and high-density lipoproteins). Precision of determination (coefficient of variation, CV, %) was the same for beta- and low-density lipoproteins (1.6%), and for pre-beta- and very-low-density lipoproteins (3.7%); however, determination of alpha-lipoprotein cholesterol was more precise (1.4%) than that of high-density lipoprotein cholesterol (3.1%). Analytical recovery of lipoprotein cholesterol was the same for both methods (98--100%) and the results were closely correlated (r = 0.943). The procedure has been used to determine the cholesterol content of plasma lipoprotein fractions of apparently healthy adults (both sexes). Lipoprotein cholesterol concentrations in our population sample compare well with those reported for other groups of similar age, in particular Stanford long-distance runners.

Adult↗
PubMed1979

Biosynthesis of acylglycerol fatty acids in dog arteries.

The incorporation of (2-14C) acetate into the diacylglycerol and triacylglycerol fatty acids of three aortic layers and of the coronary arteries of the dog was investigated. In all tissues of the health animals, 50-60% of the label was found in the fatty acids greater than C16. This percentage was significantly higher in the diacylglycerols of the aortic media than in the adjacent layers or in the triacylglycerols of the media preparation. Under the influence of an atherogenic diet rich in cholesterol, incorporation of the label into the long chain fatty acids of the acylglycerols was markedly elevated in the aortic media and in the coronary artery. These results are interpreted in terms of metabolic alterations due to hypoxia in the normal aortic media and under hypercholesterolemic conditions. An active metabolic role of the diacylglycerols without net accumulation in the aortic media is discussed. In addition, the present data lend support to recent results on the coronary arteries and their susceptibility to atherogenesis.

Acetates↗
PubMed1978

Quantitative high-performance thin-layer chromatography of lipids in plasma and liver homogenates after direct application of 0.5-microliter samples to the silica-gel layer.

Lipid profiles were determined by high-performance thin-layer chromatography (HPTLC) after direct application of 0.5 microliter plasma from capillary blood to the silica-gel layer. Coefficients of variation for the fluorescence measurements were 2.1% for phosphatidylcholine. The recovery of known amounts of lipid was 96--100%. A linear relationship between peak area and amount of lipid was found in the nmole range, corresponding to the amount of lipid in 0.125--0.75 microliter Lipid-Trol, which served as the standard reference sample. The plasma lipids of healthy subjects and of patients suffering from various illnesses were analyzed using reference methods and HPTLC. Identical values were obtained for cholesterol esters, triacylglycerols and phosphatidylcholine. Free cholesterol values determined by HPTLC were slightly lower (7%). The correlation between data obtained by reference methods and HPTLC was as follows: cholesterol, r = 0.938; cholesterol esters, r = 0.964; triacylglycerols, r = 0.985; phosphatidylcholine, r = 0.938. The separaiton and quantitation of liver lipids using HPTLC after direct application of the tissue homogenate to the silical-gel layer was carried out. Comparison with reference methods revealed that HPTLC gave higher cholesterol values (24%). The triacylglycerol concentrations, however, were identical under both methods and correalted satisfactorily (r = 0.959).

Adult↗