Mutual Inhibitory Effect of (−)-Mandelic Acid and Certain Sulfonamides on the Kinetics of Their Urinary Excretion in Humans

1969 ◽  
Vol 58 (11) ◽  
pp. 1318-1324 ◽  
Author(s):  
Fredrick M. Kamienny ◽  
Martin Barr ◽  
Janardan B. Nagwekart
Keyword(s):  
Urinary Excretion ◽  
Mandelic Acid ◽  
Inhibitory Effect ◽  
Kinetics Of

The effect of origin and physico-chemical properties on the kinetics of reduction of mixed NiO-Fe2O3 oxides with hydrogen

1986 ◽  
Vol 51 (10) ◽  
pp. 2098-2108 ◽  
Author(s):  
Milan Pospíšil ◽  
Jan Topinka
Keyword(s):  
Mixed Oxides ◽  
Mutual Influence ◽  
Spinel Phase ◽  
Chemical Properties ◽  
Inhibitory Effect ◽  
Chemical Parameters ◽  
Physico Chemical ◽  
Preliminary Annealing ◽  
Kinetics Of ◽  
Kinetics Of Reduction

We investigated the effect of origin and some physico-chemical parameters on the kinetics of reduction with hydrogen of two series of mixed NiO-Fe2O3 oxides differing by their composition, the character of their precursors (mixed crystalline nitrates and coprecipitated hydroxides) and their decomposition temperature.This effect manifested itself by different magnitudes of specific surfaces of the mixed oxides and coherent regions of present phases as well as by different oxidizing abilities of the surface and differences in morphology and phase composition of corresponding samples in both series investigated. Nonlinear or nonmonotonous composition dependences of physico-chemical parameters investigated point to a mutual influence of individual components, which is also a function of the system origin and which modifies its reactivity during its reduction with hydrogen. The kinetics of the reduction was studied thermogravimetrically at 320-410 °C. The reduction of oxides of the hydroxide origin is catalytically accelerated by primarily reduced nickel, whereas in corresponding samples of the nitrate series, the total NiO is bound to the spinel phase and the reduction is delayed. Experimental IR spectra, the effect of preliminary annealing and DTA of the mixed oxides point to an inhibitory effect of water, which is constitutionally bound in trace admixtures of the goethite phase, on the kinetics of reduction of samples in the hydroxide series.

Human metabolism and urinary excretion kinetics of di-n-butyl adipate (DnBA) after oral and dermal administration in three volunteers

2021 ◽  
Vol 343 ◽  
pp. 11-20
Author(s):  
Benedikt Ringbeck ◽  
Daniel Bury ◽  
Alexandra Gotthardt ◽  
Heiko Hayen ◽  
Rainer Otter ◽  
...  
Keyword(s):  
Urinary Excretion ◽  
Human Metabolism ◽  
Excretion Kinetics ◽  
Dermal Administration ◽  
Kinetics Of

Effect of Hypertonic Sucrose Upon the Immune Bactericidal Reaction

1970 ◽  
Vol 1 (1) ◽  
pp. 51-55
Author(s):  
Louis H. Muschel ◽  
Linda J. Larsen
Keyword(s):  
Cell Death ◽  
Cell Wall ◽  
Enzymatic Reaction ◽  
Inhibitory Effect ◽  
Lag Phase ◽  
Inner Membrane ◽  
Bactericidal Antibody ◽  
Kinetics Of ◽  
Free Serum ◽  
Supporting Structures

This study was performed to determine the mechanism whereby hypertonic sucrose inhibits the immune bactericidal reaction. Other investigators had postulated that the initial attack of complement (C) on the cell wall was followed with lysozyme-containing whole serum by an enzymatic reaction upon the peptidoglycan substrate resulting in cell death. In the absence of serum lysozyme, secondary lethal changes might occur from damage to the cell's inner membrane as a result of osmotic forces in the presence of a defective cell wall. Hypertonic sucrose giving rise to plasmolysis and protection of the inner membrane was presumed to differentially inhibit the immune response mediated by lysozyme-free serum. The experimental results observed in this investigation have indicated, however, that the inhibitory effect of sucrose upon the bactericidal reaction may be explained simply by its anticomplementary effect and not by any effect on the bacterial cell. This view was supported by the following observations: (i) the comparability of the inhibitory effect of sucrose upon the immune hemolytic and bactericidal reactions, (ii) the comparable percentage loss in bactericidal activity of whole serum and lysozyme-free serum resulting from hypertonic sucrose, (iii) bactericidal antibody titrations were relatively unaffected and C titrations markedly inhibited by sucrose, (iv) the inhibitory effect of sucrose on the bactericidal reaction was unaffected by prior growth of the organism in the presence of sucrose, (v) the kinetics of the bactericidal reactivity of lysozyme-free serum in hypertonic sucrose, compared with whole serum, did not reveal a prolonged lag phase with lysozyme-free serum, but simply diminished reactivity at all times. These observations are compatible with the view that the C attack upon the outer surface of gram-negative bacteria, which plays a part in the cell's permeability control, may account for cell death. In this regard, the immune bactericidal reaction is quite comparable to the lysis of red cells or nucleated cells by C despite the lack of overt lysis in bacteria, probably because of their underlying supporting structures.

Biochemical and Clinical Effects of Ethane-1-Hydroxy-1,1-Diphosphonate in Calcium Nephrolithiasis

1978 ◽  
Vol 54 (5) ◽  
pp. 509-516 ◽  
Author(s):  
J. M. Baumann ◽  
S. Bisza ◽  
H. Fleisch ◽  
M. Wacker
Keyword(s):  
Urinary Excretion ◽  
Average Rate ◽  
Stone Formation ◽  
Placebo Treatment ◽  
Inhibitory Effect ◽  
Urinary Concentration ◽  
Clinical Effects ◽  
Inorganic Pyrophosphate ◽  
Urinary Tract Stones ◽  
Calcium Crystals

1. The short- and longer-term effects of ethane-1-hydroxy-1,1-diphosphonate (EHDP), an inhibitor of crystal growth and potential preventive agent against urinary tract stones in man, have been studied. 2. Measurement of urinary excretion of EHDP was used to define the best dosage regimen. When 4·4 mmol of EHDP was given daily in four divided doses the urinary concentration of EHDP achieved was high enough (10−5 mol/l) to inhibit the crystallization of calcium crystals throughout the day. 3. Nine patients with recurrent calcium stones were given this dose of EHDP daily for 12 months and seven were then studied for a further 12 months under placebo. During treatment with EHDP, inhibitory activity in urine towards precipitation of calcium phosphate was restored from low values to greatly above normal. This could be accounted for by the inhibitory effect of EHDP itself, coupled with an increase in urinary inorganic pyrophosphate. After stopping EHDP the excretion of EHDP rapidly fell to undetectable levels but the excretion of pyrophosphate remained elevated throughout the 12 months of placebo treatment. EHDP also induced a rise in plasma phosphate and an increase in the urinary excretion of oxalic acid and uric acid, but these changes were all fully reversible when EHDP was stopped. 4. The average rate of stone formation per patient per year decreased from 2·4 to 0·2 during treatment with EHDP and remained low during the following 24 months. However, the dose needed for this effect is known to affect bone turnover and mineralization.

Charakterisierung und Kinetik des in der Rattenplacenta vorkommenden mikrosomalen Enzyms, das den Wasserstoff-Transfer von Oestradiol auf Androstendion katalysiert / Characterization and Kinetics of the Microsomal Enzyme of Rat Placenta which Functions as a “Transhydrogenase” between Estradiol-17β and Androstenedione

1971 ◽  
Vol 26 (7) ◽  
pp. 710-719 ◽  
Author(s):  
Kunhard Pollow ◽  
Barbara Pollow
Keyword(s):  
Hydrogen Transfer ◽  
Microsomal Fraction ◽  
Close Relation ◽  
Inhibitory Effect ◽  
Magnesium Ions ◽  
Michaelis Constant ◽  
Temperature Optimum ◽  
Optimum Ph ◽  
Kinetics Of ◽  
Estradiol 17Β

The microsomal fraction of rat placenta contains a 17β-hydroxysteroid-oxidoreductase which transfers hydrogen from position 17 of estradiol to androstenedione. This hydrogen transfer is dependent on NAD, NADP as cofactor is without effect. The optimum pH is at 6,9. In the presence of NAD the Michaelis constant for estradiol is 4,17 · 10-5м at pH 7,4. In the presence of androstenedione in the incubation medium the Km-value for estradiol is decreased, which indicates an increased affinity for the enzyme. The temperature optimum of the enzyme is 38 °C. Addition of SH-blocking agents inhibited the enzyme activity. Zinc and magnesium ions had an inhibitory effect on the “transhydrogenase” and B-NADPT specifically labelled from [1-T]-glucose showed that the non-effect of NADP on transhydrogenation from estradiol to androstenedione resulting in reduction of position 17 is not due to different stereospecifity.The results show a close relation between the oxidative metabolism of estradiol and the reduction of androstenedione, indicating that estradiol-17β, as the preferred hydrogen-donating substrate, is an essential component of the androstenedione-hydrogenating system in the microsomal fraction of rat placenta.

Metabolism and urinary excretion kinetics of di(2-ethylhexyl) terephthalate (DEHTP) in three male volunteers after oral dosage

2016 ◽  
Vol 90 (7) ◽  
pp. 1659-1667 ◽  
Author(s):  
Frederik Lessmann ◽  
André Schütze ◽  
Tobias Weiss ◽  
Angelika Langsch ◽  
Rainer Otter ◽  
...  
Keyword(s):  
Urinary Excretion ◽  
Oral Dosage ◽  
Excretion Kinetics ◽  
Male Volunteers ◽  
Kinetics Of

Human Metabolism and Urinary Excretion Kinetics of Nonylphenol in Three Volunteers after a Single Oral Dose

2021 ◽  
Author(s):  
Benedikt Ringbeck ◽  
Vladimir N. Belov ◽  
Christoph Schmidtkunz ◽  
Katja Küpper ◽  
Wolfgang Gries ◽  
...  
Keyword(s):  
Oral Dose ◽  
Urinary Excretion ◽  
Single Oral Dose ◽  
Human Metabolism ◽  
Excretion Kinetics ◽  
Kinetics Of
Sign in / Sign up

Export Citation Format

Share Document