The substrate specificity of the avian renal organic cation exchanger was examined in isolated renal brush-border membrane vesicles. Endobiotic and xenobiotic organic cations (OCs) were tested at a concentration of 100 microM for cis-inhibition of 14C-tetraethylammonium (TEA)/H+ exchange and at 1 mM for trans-stimulation of 14C-TEA efflux. The xenobiotic cations amiloride, cimetidine, mepiperph...

We propose to detect isomorphisms of algebraic modular speci cations, by representing speci cations as diagrams over a category C0 of base speci cations and speci cation morphisms. We start with a formulation of modular speci cations as terms, which are interpreted as diagrams. This representation has the advantage of being more abstract, i.e. less dependent of one speci c construction than ter...

The properties of the cGMP-dependent channel present in membrane vesicles prepared from intact isolated bovine rod outer segments (ROS) were investigated with the optical probe neutral red. The binding of neutral red is sensitive to transport of cations across vesicular membranes by the effect of the translocated cations on the surface potential at the intravesicular membrane/water interface (S...

Many approaches to programming emphasize the use of interfaces. The basic idea is to decompose programs into modules and to specify how each module's interface behaves. This makes it easier to reason about programs because one can rely on a module's speci cation rather than examining its implementation, which is more complicated. Although programmers bene t from speci cations when reasoning abo...