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Biomedical subjects

K Jung

Publications and source records attributed to K Jung.

At least 289 records · Page 16Linked to original sources

[15N] ammonium test for liver function diagnosis.

The functional state of the liver can be assessed by oral administration of 15N labelled ammonium chloride (tracer) and subsequent isotope analysis of [15N]urea and [15N]ammonia in urine. Clinical tests based on the ratio of the excess abundances of [15N]ammonia to [15N]urea excreted in urine 3 hours after oral administration of the tracer gave values for patients with liver diseases which differed significantly from these of healthy subjects.

Ammonia↗

Sialidase from different sources compared for electrophoretically separating serum alkaline phosphatase fractions from liver and bone.

We compared sialidase (neuraminidase; EC 3.2.1.18) from Vibrio cholerae, Clostridium perfringens, and Arthrobacter ureafaciens, seeking to improve the electrophoretic separation of the liver and bone isoenzymes of alkaline phosphatase (EC 3.1.3.1) on cellulose acetate membranes. Resolution is decisively determined by the type and activity of sialidase used in the preincubation of serum sample. Sialidase from Arthrobacter ureafaciens is not suited for this method. For optimal separation of the two isoenzymes we recommend the use of sialidase from Vibrio cholerae, determination of its activity with a standard procedure such as described here (mucin or sialyl lactose as substrates), and a final concentration of sialidase activity of 2.0 or 2.9 U/L (measured with mucin or sialyl lactose) in the incubation mixture.

Alkaline Phosphatase↗

Quality control material for activity determinations of urinary enzymes.

We examined the stability of N-acetyl-beta-D-glucosaminidase (EC 3.2.1.30), alanine aminopeptidase (EC 3.4.11.2), alkaline phosphatase (EC 3.1.3.1), gamma-glutamyltransferase (EC 2.3.2.2), and lysozyme (EC 3.2.1.17) in urine prepared by gel filtration and supplemented with albumin, or ethylene glycol, or ethylene glycol plus albumin during storage at -20 degrees C for a period of 12 months. The stability was assessed by linear regression analysis of monthly values versus time. All enzymes except for gamma-glutamyltransferase could be considered stable for about one year in all three control materials provided that maximum change of 10% of the starting enzyme activity is accepted as tolerable. If ethylene glycol is used as stabilizer, its suitability must be tested and its inhibitory effect on enzyme activities must be taken into account in intermethod comparisons, because in some methods, it may be removed in a pretreatment step.

Acetylglucosaminidase↗

The influence of a steroid hormone and of physical exercise on protein metabolism in rats.

The influence of an anabolic steroid hormone preparation and of a physical exercise training program was studied on the nitrogen and protein metabolism in rats with the help of the 15N tracer technique and the emission spectrometric 15N isotope analysis. For the determination of the dynamic parameters of the protein metabolism graphic (stochastic) and computer aided compartmental methods were compared. Using as a stochastic approach the area-method the animals showed significant differences in the protein turnover parameters under the influence of hormone treatment and (or) physical stress by swimming exercise in comparison to the controls.

Anabolic Agents↗

Changed composition of high-density lipoprotein subclasses HDL2 and HDL3 after renal transplantation.

The concentrations of cholesterol in the high density lipoprotein (HDL) fraction and the HDL2 and HDL3 subclasses were compared in 333 male renal transplant recipients, 36 male patients on maintenance hemodialysis, and 43 healthy men. The subclasses were separated by a precipitation method using polyethylene glycol 6000 and dextran sulphate. In hemodialyzed patients, total HDL cholesterol and both subclasses were reduced. In renal transplant recipients, both total HDL cholesterol and HDL2 were normal, whereas HDL3 remained reduced, analogous to hemodialyzed patients. It can be concluded that a successful renal transplantation has a beneficial effect on HDL metabolism and thus on the development of atherosclerosis.

Cholesterol, HDL↗

Evaluation of protein metabolism in clinical practice.

The application of stable isotopes creates further possibilities for our understanding of the metabolism. New concepts especially for non-invasive diagnostic procedures could be developed. An important step in our research program was the performing of a 1-year experiment on a volunteer. On the basis of a 10-pool model we received a lot of informations. Based on this knowledge we developed 2 simplified methods for calculating whole body protein turnover. Knowing the problems with whole body protein calculations we intensified our intentions for determining the protein enrichment in organs and isolated cells (hepatocytes), estimating at the same time the precursor pool in the cells. Of special importance was an extensive study, wherein all those 15N-estimations were performed we are able to do up to now. We calculated whole body protein, but especially we studied the enrichment of the cellular protein fractions in hepatocytes, of plasmaproteins, and of the intracellular precursor pool. This study is the base for further tracer investigations.

Animals↗

Diuresis-dependent excretions of low-molecular mass proteins in urine: beta 2-microglobulin, lysozyme, and ribonuclease.

An investigation was carried out into how the low-molecular mass proteins beta 2-microglobulin, lysozyme, and ribonuclease were excreted over 8 h after high fluid intake (22 ml/kg of body weight in 15 min). With increasing urine flow rate the amount of lysozyme excreted per hour or per millimole creatinine increased more markedly than that of beta 2-microglobulin while at the same time the excretion rate of ribonuclease decreased. The effect of urinary flow upon the excretion rates of the various low-molecular mass proteins has to be considered as a preanalytical factor when these proteins are used as indicators of tubular dysfunction.

Adult↗

Urinary enzymes and low-molecular-mass proteins as indicators of diabetic nephropathy.

We measured the excretion rates of six urinary enzymes that either originate from the proximal renal tubule, like alanine aminopeptidase (EC 3.4.11.2), alkaline phosphatase (EC 3.1.3.1), gamma-glutamyltransferase (EC 2.3.2.2), and N-acetyl-beta-D-glucosaminidase (EC 3.2.1.30), or that are typical low-molecular-mass proteins, like lysozyme (EC 3.2.1.17) and pancreatic ribonuclease (EC 3.1.27.5). These rates were compared with those of total protein and albumin in urine of 36 insulin-dependent diabetic men and 30 healthy men. Seventeen of the diabetics had "clinical proteinuria," defined as excretion of more than 7.5 g of protein per mole of urinary creatinine (group B). Group A comprised the 19 diabetics without proteinuria. Except for gamma-glutamyltransferase, the excretions of enzymes and proteins were significantly higher in diabetics than in controls and were greater in group B than in group A. N-Acetyl-beta-D-glucosaminidase was the analyte most often increased in group A (89%), followed by albumin and alkaline phosphatase (each 32%). All patients in group B showed increased excretion of N-acetyl-beta-D-glucosaminidase. We conclude from the comparative data that this enzyme may be useful as an early predictor of diabetic nephropathy.

Acetylglucosaminidase↗

[The low molecular weight proteins ribonuclease, beta 2 microglobulin and lysozyme in the serum and urine of patients with chronic kidney diseases].

The diagnostical relevance of the low-molecular proteins ribonuclease, beta 2-microglobulin and lysozyme in serum and urine to detect a reduced glomerular filtration rate was examined in 52 patients with chronic renal diseases. The radioisotope clearance using 99mTc-DTPA was the base reference; the reference values of the low-molecular proteins were estimated in a control group. Ribonuclease was increased above the upper borderline value, if the glomerular filtration rate was lower than 1.24 ml s-1. Creatinine, beta 2-microglobulin and lysozyme remain yet in part in the normal range. The estimation of the ribonuclease in serum is suitable to detect an impaired glomerular filtration rate if the creatinine value is still not increased. Thereby, the diagnostics in renal diseases may be improved in the creatinine-blind area.

Adult↗

[Comparison of inulin and creatinine clearance determinations in anesthesized and conscious rats].

Two investigation methods of the renal function by means of the inulin and the endogenous creatinine clearance in narcotized and conscious rats are described in detail. The inulin clearance was 0.84 +/- 0.16 ml/min/100 g BW. The results of the creatinine clearance obtained by 6 various methods are widely different due to co-determination of foreign chromogens. Therefore, it is important to compare these results with the results of other analytical methods determining only the "true" creatinine.

Anesthesia, General↗

Different susceptibility of cortical and medullary rat kidney mitochondria to ischemic injury.

Rat kidneys were exposed for different times to in vitro ischemia at 37 degrees C. Then the mitochondria of cortex and medulla were isolated and their respiratory qualities were determined. In dependence on the ischemic time, the active respiration (state 3) and the respiratory control index decreased whereas the resting state respiration (state 4) increased. The cortical mitochondria were affected more strongly by ischemia than medullary mitochondria. Therefore, the different susceptibility of cortical and medullary mitochondria to ischemia does not explain the suggested high risk of medulla for ischemia.

Animals↗

Diagnostic significance of different urinary enzymes in patients suffering from chronic renal diseases.

The urinary enzymes alanine aminopeptidase (EC 3.4.11.2), alkaline phosphatase (EC 3.1.3.1), gamma-glutamyltransferase (EC 2.3.2.2), N-acetyl-beta-D-glucosaminidase (EC 3.2.1.30), and ribonuclease (EC 3.1.4.22) were measured in 66 healthy persons and 52 patients suffering from chronic renal diseases (pyelonephritis, glomerulonephritis). The residual renal function of patients characterized by 99mTc-diethylenetriaminopentaacetate isotope clearance was only moderately reduced. Except for gamma-glutamyltransferase, patients generally showed increased urinary enzyme excretions. N-Acetyl-beta-D-glucosaminidase was more sensitive to detect renal dysfunction than the other enzymes and the conventional parameters serum creatinine, total protein excretion, and the measurement of glomerular filtration rate. The determination of this enzyme can be recommended as a suitable diagnostic parameter in nephrology.

Acetylglucosaminidase↗