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K Jung

Publications and source records attributed to K Jung.

At least 235 records · Page 13Linked to original sources
PubMed1992

Practical approach for determining glomerular filtration rate by single-injection inulin clearance.

We compared the glomerular filtration rate as measured by a single-injection inulin clearance with that measured by a standard isotope method with 99mTc-labeled diethylenetriaminopentaacetic acid in 21 subjects with glomerular filtration rates greater than 35 mL/min. After a bolus injection of 5 g of inulin, blood samples were taken 20, 45, 90, 120, 145, 180, and 240 min afterwards. Inulin was measured by optimized chemical or enzymatic methods of high analytical sensitivity to determine inulin at low concentrations. We used the one-compartment model and inulin concentrations measured at two sampling times to calculate the glomerular filtration rate from the data of the disappearance curve of inulin. Inulin concentrations at 20 and 240 min after injection of the inulin bolus were suited to estimate glomerular filtration rate by this procedure, resulting in values (y) comparable with those obtained by isotope technique (x). The relationship to the isotope technique was characterized by the equation y = +4.80 mL/min + 0.92x (r = 0.97). The single-injection inulin clearance determination can detect a decrease of glomerular filtration rate at the beginning of kidney damage, given that our study included subjects with glomerular filtration rates greater than 35 mL/min. We conclude that the glomerular filtration rate can be determined by analyzing only two blood samples after a bolus injection of inulin.

Adult↗
PubMed1992

Urinary mutagenicity in vegetarians and people on a mixed-western diet.

This investigation was undertaken to determine whether the consumption of an ovolacto-vegetarian diet and a mixed-western diet by a group of 31 and 32 persons respectively resulted in the excretion of different levels of mutagens in the urine of these two dietary groups. All subjects were male participants of the "Deutschlandlauf 1987" and consumed strictly controlled diets with limited energy supply and a defined protein/fat/carbohydrates relation. 24-h Urines were collected before the start of the race, mutagens were extracted by a combination of the XAD-2 method of Yamasaki and Ames (53) and the blue-cotton method of Hayatsu et al. (20), and aliquots were assayed for mutagenicity with Salmonella typhimurium strains TA 98 and TA 1538 in the presence of an activating system (S 9-mix). Urinary mutagenicity was significant but at considerable variance in 26 (13) vegetarians and non-vegetarians as estimated with strain TA 1538 (TA98). No statistically significant difference could be detected between the vegetarian and the mixed-western dietary groups in any urinary mutagenicity parameter given below. In detail the following mean values were obtained: 2.46 +/- 1.87 his+ revertants/ml urine, 3,333 +/- 1,835 revertants in 24-h urines, and 5.01 +/- 3.1 revertants/mg creatinine for vegetarians and 3.13 +/- 2.18 his+ revertants/ml urine, 4,611 +/- 5,913 revertants in 24-h urine, and 8.98 +/- 20.17 revertants/ml creatinine for non-vegetarians with S. typhimurium TA 98 and 3.75 +/- 2.88 his+ revertants/ml urine, 6,094 +/- 7,885 revertants in 24-h urine, and 10.88 +/- 21.14 revertants/mg creatinine for vegetarians and 4.17 +/- 2.71 his+ revertants/ml urine, 5,705 +/- 4,421 revertants in 24-h urines, and 6.97 +/- 9.29 revertants/mg creatinine for non-vegetarians with strain 1538. Considerable individual variation in levels of urinary mutagenicity in spite of consumption of identical, controlled diets may at least in part depend on inherent differences of absorption, metabolism, and excretion patterns of mutagens by individuals, preventing collective comparisons of the extent of exposure to dietary mutagens.

Adult↗
PubMed1991

Ischemia decreases the content of the adenine nucleotide translocator in mitochondria of rat kidney.

The activity of the adenine nucleotide translocator is decreased at ischemia. Studies were undertaken to elucidate changes in the adenine nucleotide translocator by determining its content in mitochondria of ischemic rat kidney. After 60 min of ischemia, the content of the adenine nucleotide translocator amounted only to about 55%, of that measured in control mitochondria. At the same time, the flux control coefficient was increased. These changes paralled the well-known effects of ischemia: the decrease in oxidative phosphorylation and in adenine nucleotides. It is supposed that the decrease in the adenine nucleotide translocatar content accounts, at least partially, for the ischemia-induced impairment of mitochondria.

Animals↗
PubMed1991

[The body muscle compartment and its relationship to food absorption and blood chemistry during an extreme endurance performance].

The purpose of the study was to examine the changes of the muscle's fat-free compartment and its relation to the corresponding biochemical and nutritional parameters of 42 men and 13 women, the participants of an ultra long-distance run of 1000 km (20 days of daily running 50 km). The muscle-fractions initially increased, decreased in the middle phase, and remained stable for the rest of the run. Significant changes of the fat-free weight were registered from the 11th day on, the LBM decreasing until the middle of the distance; then the lean body mass enlarged. All the muscle-circumferences were reduced with the exception of the thigh, which grew, paralleling the CK/CKMB-concentrations, this phenomenon being due to the high mechanical stress of the lower extremities. The biochemical parameters exhibit a strain-related reaction of adaptation within the initial 6 days, the hormones and protein-concentration increasing in the beginning and falling from the third day on, uric acid and CK/CKMB-activity decreasing from the 6th day on. The consecutive parallel reduction of both uric acid, urea, and muscle measurements might be seen as a special endurance-related clearance-mechanism of potential toxicants. The negative relationship between the changes of muscle measurements and the cumulative protein intake and the catabolic constellation of the clinical-chemical values might suggest that the absolute protein intake of 1.7 g/kg body mass should be increased in order to diminish the loss of musculature during an ultra-long distance run.

Absorption↗
PubMed1991

[Changes in foot dimensions during extreme endurance running].

55 (including 13 women) of 110 starters of a 1000-km-ultra long distance run reached their goal after 20 days of daily running 50 km. As a consequence of the burden of running 500 km the flat feet form is diminished, which might be caused by an increased reactive muscular tonus. The increase of foot length and breadth measures between the 9th and 16th day, however, demonstrates the opposite effect, when a "physiological limit" of circa 500 km is exceeded.

Anthropometry↗
PubMed1991

Development of urea-synthesizing capacity in preterm infants during the first weeks of life.

The urea-synthesizing capacity of the liver was studied in 20 healthy preterm infants during the first month of life. The urea-synthesizing capacity was estimated by the ratio of 15N abundances of ammonia and urea in the 6-hour urine after administration of 3 mg 15N-labelled ammonium chloride/kg body weight. The ratio increases with increasing protein intakes from the 2nd to the 3rd week of life. On protein intakes of more than 3 g/kg/protein day from the 3rd week to the end of the 2nd month of life, the ratio decreases suggesting a maturation of the urea cycle during the first weeks of life.

Age Factors↗
PubMed1991

Methods compared for determining activity of N-acetyl-beta-D-glucosaminidase in urine without pretreatment of sample: different sensitivity and species effect.

N-Acetyl-beta-D-glucosaminidase (NAG) activities in the urine of men and rats were measured with methods recommended as procedures without pretreatment of the urine sample. Four different derivatives of NAG were compared for determination: 4-nitrophenyl; 3,3-dichlorophenylsulfonphthaleinyl; 3-cresolsulfonphthaleinyl, and 2-methoxy-4-(2-nitro-vinyl)phenyl. The conventional test using the 4-nitrophenyl derivative showed the highest activities and correlated very well with the other tests. There are method-dependent differences between NAG activities measured in men and rats due to the different Km values and inhibitory effects by urea.

Acetylglucosamine↗
PubMed1991

Multiple forms of N-acetyl-beta-D-glucosaminidase of human urine: isolation, properties and the development of a practical approach of differentiation.

The two major tissue forms of N-acetyl-beta-D-glucosaminidase, A and B, and a minor form M were isolated from human urine by chromatography on DEAE-Trisacryl M and Con A-Sepharose. Forms A and B have a Km-value of about 0.75 mM for 4-nitrophenyl-beta-2-acetamido-2-deoxy-D-glucopyranoside, form M a corresponding value of 1.57 mM. The pH optimum was for all forms between pH 4.0 and 4.8. Forms A and M were heat labile, while form B was relatively heat stable. Using different binding properties of forms A and B on Trisacryl, a batch method was developed to differentiate both forms in human urine. This method can be easily performed and gives reproducible results. The intra-run and between-run precision for the separation of the two forms were below 10%.

Acetylglucosaminidase↗
PubMed1991

Enzyme activities in urine: how should we express their excretion? A critical literature review.

Different methods and reference bases for characterizing the excretion of urinary enzymes (relation to volume, time, creatinine, specific gravity, osmolality and fractional excretion) are reviewed with regard to their advantages and disadvantages when using urinary enzyme excretion as a diagnostic tool. The problems of timed and untimed urine samples for the analysis of urinary enzyme excretion and the influence of diuresis on the quantity and composition of enzymes excreted are discussed. The use of the second morning urine as a random urine sample, and determination of the relation of enzyme activity to urinary creatinine (enzyme/creatinine ratio; enzyme/creatinine index) represent a satisfactory compromise for the characterization of urinary enzyme excretion. The calculation of enzyme excretion per unit time or other modes of expression should be used only in special cases.

Body Constitution↗
PubMed1991

Evaluation of methods for determining N-acetyl-beta-D-glucosaminidase in urine of rats without purification of urine samples.

N-Acetyl-beta-D-glucosaminidase (NAG) activities in urine of rats were measured with methods recommended as procedures without the pretreatment of urine sample. Four different derivatives [4-nitrophenyl; 3-cresolsulfonephthaleinyl; 3,3'-dichlorophenylsulfonephthaleinyl; 2-methoxy-4-(2-nitrovinyl)phenyl] of N-acetyl-beta-D-glucosaminide were compared for determination. The conventional test using the 4-nitrophenyl derivative showed the highest activities and was very well correlated with the other tests. The test using the 3,3'-dichlorophenylsulfonephthaleinyl substrate is most convenient and practical to determine NAG in small animals because it is, in contrast to the other three discontinuous (endpoint) tests, a continuous (kinetic) assay which can be easily adapted to clinical chemistry analyzers.

Acetylglucosaminidase↗
PubMed1991

[Clinical and epidemiological application of carbachol for the testing of bronchial hyperreactivity in school-age].

Airway reactivity was investigated by inhalation of the cholinergic agent carbachol. A standardized Carbachol challenge test (CCT) was carried out in a cumulative manner in 59 school-aged children as well as 10 not asthmatic individuals. The carbachol aerosol was delivered by jet nebulization. It was administered by inhalation of stepwise twofold increasing cumulative doses from a balloon taking tidal breaths. The inhalation was finished at the dose step eliciting a 100% increase in R(aw). Bronchial reactivity was derived by linear regression from the dose-response function. Bronchial sensitivity was registered by the threshold dose. Calculated on the bronchial reactivity of 57 asthmatics the asthma-related sensitivity of the CCT was 83%. The specificity was 90%. In 7 children the week-to-week reproducibility was tested: 6 children showed discrepancies of the threshold dose of less than two steps, in one case a shift of two steps was observed. In none of the probands a severe systemic side effect occurred. The carbachol challenge test is an appropriate method to distinguish asthmatic children from the normal population. The validity and good reproducibility as well as the feasibility in children makes the procedure valuable for pediatric investigations of bronchial hyperreactivity as a common feature in asthma.

Bronchial Hyperreactivity↗
PubMed1991

[A new kinetic method for measuring beta-N-acetylglucosaminidase activity in urine].

A short overview of the biochemical and technical basis for measurement of beta-N-acetylglucosaminidase (beta-NAG, EC 3.2.1.30) is given. Advantages and disadvantages of various methods are discussed and the need has to be well founded to develop a new colorimetric assay. Some technical details of a new colorimetric test for the measurement of beta-NAG in urine are described.

Acetylglucosaminidase↗
PubMed1991

[Evaluation of methods for the analysis of low insulin concentrations in serum].

Three methods of the determination of insulin in serum were optimized in order to determine low concentrations of this analyte reliably (Method I: enzymatic after acidic hydrolysis of inulin; Method II: by anthrone/sulfuric acid reagent; Method III: by cysteine/tryptophan reagent). The interfering reaction of glucose in the methods I and II was avoided by the preincubation of samples with glucose oxidase/catalase reagent. The detection limit of all three methods was below 5 mg/l and the within-run precision amounted to values below 5%. Method I and II gave identical results. In comparison with these two methods, method III resulted in inulin values by about 8% lower, because inulin, depending on the lot used, contained alkali-labile fractions which were destroyed during the sample preparation. Method II is recommended for routine measurements because of its an analytical reliability and its cost-effectiveness.

Catalase↗