Adenosine and/or homocysteine causes endothelial cell apoptosis, a mechanism requiring protein tyrosine phosphatase (PTPase) activity. We investigated the role of focal adhesion contact disruption in adenosine-homocysteine endothelial cell apoptosis. Analysis of focal adhesion kinase (FAK), paxillin, and vinculin demonstrated disruption of focal adhesion complexes after 4 h of treatment with ad...

An intestinal preparation from the common eel (Anguilla anguilla) was characterized for both mucosal to serosal and serosal to mucosal transport of water, alanine, sodium and chloride. The preparation showed a net outflux of water and a net influx of alanine, and no net fluxes of sodium or chloride. The influxes of all four substances and the outflux of water were inhibited by ouabain, while th...

Polysaccharide-containing vesicles were collected from secretory cells maintained in liquid culture. Characterization of membrane-associated nucleosidephosphatases revealed that the vesicles specifically hydrolyze ATP, have a pH optimum between 6.0 and 6.5, and are stimulated by inorganic cations, especially K(+). The ATPase activity in these vesicles was inhibited by orthovanadate and N,N'-dic...

The activity of glyoxalase I from the soluble fraction of diabetic rat liver was found to decrease as compared to the control. Sodium orthovanadate in drinking water and Trigonella foenum graecum seed powder when administered to these diabetic animals were found to reverse the activity of glyoxalase I to control values. A combination of the above two antidiabetic compounds showed a better rever...

In the present work we have partially characterized an ecto-phosphatase activity in Crithidia deanei, using viable parasites. This enzyme hydrolyzed p-nitrophenylphosphate at a rate of 3.55 +/- 0.47 nmol Pi/h x 10(8) cells. The dependence on p-NPP concentration shows a normal Michaelis-Menten kinetics for this phosphatase activity and the value of the apparent Km for p-NPP was 5.35 +/- 0.89 mM....

Collagenase production by chondrocytes appears to play a major role in the development of osteoarthritis. Although the mechanisms regulating collagenase production by chondrocytes are not known, incubation of bovine chondrocytes in serum markedly decreases collagenase production. Since serum has been demonstrated to increase levels of phosphotyrosine (P-Tyr) in several cell types, we determined...