Protein adsorption at the interface between charged polymer substrata and migrating osteoblasts.

The in vitro migratory morphology of neonate rat calvarial osteoblasts on positively or negatively-charged polymer substrata was observed using scanning (SEM) and transmission electron microscopy (TEM). Proteins adsorbed from the culture medium onto these charged substrata were desorbed using 2% SDS and separated using polyacrylamide gel electrophoresis (PAGE). The charge sign of the substrata affected both protein adsorption and osteoblast migratory morphology. Cells flattened and adapted so closely to positively-charged substrata that the ventral cell membrane could not be distinguished at TEM. On negatively-charged substrata the ventral cell membrane was readily visible, with only focal areas of close contact with the substratum. The depth of the ventral extracellular space varied with the surface charge-carrier species on the negative substrata. Two desorbed protein fractions (MW 220 and 30 kDaltons, respectively) were correlated with osteoblast spreading on positive and negatively-charged surfaces respectively. Another protein fraction was uniquely present on PAGE profiles desorbed from negatively-charged substrata. It was concluded that the migratory morphology of osteoblasts was influenced via the intermediary of specifically adsorbed proteins.

Icotidine, an antagonist of histamine at both H1 and H2 receptors.

SK&F 93319 (icotidine), 2-[4-(3-methoxypyrid-2-yl)butylamino]-5-[(6-methylpyrid-3-yl )-methyl]- pyrimidin-4-one trihydrochloride, has been identified as a novel agent which combines into one molecule the ability to antagonize the actions of histamine at H1 and H2 receptors across a similar concentration or dose range. The degree of antagonism of vascular responses to histamine exceeds that possible with either an H1- or H2-receptor histamine antagonist alone. SK&F 93319 may have therapeutic utility in conditions requiring simultaneous antagonism of histamine at H1 and H2 receptors.