Kinetics of the reaction of the first metabolite of fenitropan with some low molecular weight thiols

1989 ◽  
Vol 26 (3) ◽  
pp. 253-259 ◽  
Author(s):  
Gabor Gullner ◽  
Gyula Josepovits ◽  
Gyula Mikite
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
Kinetics Of

Kinetics of inhibition of purified bovine neutrophil matrix metalloproteinase 9 by low–molecular-weight inhibitors

2009 ◽  
Vol 70 (5) ◽  
pp. 633-639 ◽  
Author(s):  
Gregory A. Bannikov ◽  
Jeffrey Lakritz ◽  
Christopher Premanandan ◽  
John S. Mattoon ◽  
Eric J. Abrahamsen
Keyword(s):  
Molecular Weight ◽  
Matrix Metalloproteinase ◽  
Matrix Metalloproteinase 9 ◽  
Low Molecular Weight ◽  
Kinetics Of ◽  
Metalloproteinase 9 ◽  
Kinetics Of Inhibition ◽  
Bovine Neutrophil

Movements of Phosphorus Between its Biologically Important Forms in Lake Water

1973 ◽  
Vol 30 (10) ◽  
pp. 1525-1536 ◽  
Author(s):  
D. R. S. Lean
Keyword(s):  
Molecular Weight ◽  
Lake Water ◽  
Membrane Filtration ◽  
Organic Phosphorus ◽  
Gel Filtration ◽  
Particulate Fraction ◽  
Low Molecular Weight ◽  
Radioactive Phosphorus ◽  
Dissolved Phosphorus ◽  
Kinetics Of

A model consistent with the kinetics of phosphorus in epilimnetic lake water was developed. Adding 32PO4 to lake water and separating the major forms of dissolved phosphorus by Sephadex gel filtration showed that the exchange mechanism between inorganic phosphate and the particulate fraction predominates. At the same time, a low-molecular-weight phosphorus compound is excreted which combines with colloids in lake water, releasing phosphate from the colloid and making the phosphate available for "transfer" again. This rapid cycling of phosphorus between the four principal forms — the particulate fraction, the low-molecular-weight P compound, colloidal P, and phosphate — appears to contribute to formation of colloids in lake water. No direct complexing of phosphate to the colloid was observed. Only in the presence of algae, bacteria, and other particulate matter did the radioactive phosphorus move to the low-molecular weight and the colloidal forms. The low-molecular-weight compound is negatively charged, as is the colloidal P, but to a lesser degree. Both are removed by anion exchange materials along with phosphate, but the rate that they move into the fraction removed by membrane filtration is different from that for phosphate. When filtrate is refiltered a large amount of the colloidal P is retained by the filter. This complicates measurements of transfer and makes previous studies on utilization of dissolved organic phosphorus of doubtful value since corrections for filter retention were rarely, if ever, made.

KINETICS OF LOW MOLECULAR WEIGHT HEPARIN IN MAN DETERMINED BY PROTAMINE CHLORIDE

1987 ◽  
Author(s):  
V Bode ◽  
R Franz ◽  
D Welzel ◽  
H Wolf ◽  
C Harenberg
Keyword(s):  
Molecular Weight ◽  
Half Life ◽  
Ex Vivo ◽  
Plasma Concentrations ◽  
Factor Xa ◽  
Low Molecular Weight ◽  
Plasma Samples ◽  
Endogenous Compounds ◽  
Antifactor Xa ◽  
Kinetics Of

Low molecular weight (LMW) heparin is characterized by a higher affinity to antithrombin HI, less inhibition of thrombin and increased inhibition of factor Xa. The half life of the antifactor Xa activity of LMW heparin is doubled compared to normal heparin. However, these parameters reflect the pharmacodynamics rather than the kinetic of the compound. We, therefore, analyzed the kinetics of LMW heparin after i.v. injection in man using protamine chloride for gravimetric evaluation of LMW heparin in the plasma samples.Six healthy adults received 100 units per kg body weight normal heparin or 100 anti Xa units per kg LMW heparin (Sandoz AG, Niimberg, FRG). To serial samples of venous blood protamine chloride was added in serial dilutions until the thrombin inhibition was antagonized. Since factor Xa inhibition of LMW heparin cannot be abolished completely by protamine chloride, two amounts of protamine chloride were added to the plasma samples ex vivo, until factor Xa was inhibited up to 0,2 and 0,04 units/ml. The following maximal plasma concentrations (C max) and half lives (T/2) were calculated (average values):The pharmacokinetics of normal heparin show no differences on thrombin and factor Xa interaction. LMW heparin, however, interacts to 30 % with thrombin and to 100 % with factor Xa; the half life on factor Xa is twice as long as on thrombin; releases endogenous compounds with antifactor Xa activity, which are neutralized only hardly by protamine chloride;and these endogenous compounds mediate in part the longer half life.

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