Electronic Characterization of Solid Surfaces: Determination of the energy levels of electrons at surfaces is now possible over a wide energy range

At this point it would be presumptuous to suggest either that we understand very much about the electronic structure of solid surfaces or that we can specify in detail exactly what each of our tools for studying such structure is telling us. I think it is fair to say, however, that FES, UPS, and INS do make it possible for us to determine energy level spectra which can with some confidence be ascribed to the resonances of electrons in surface orbitals. It is true that INS is the more surface-selective of the two electron spectroscopies capable of producing data over at least a 10-ev energy range. We have seen intriguing differences between INS and UPS which, when we come to understand them, will most certainly reveal important characteristics of surface electronic structure and greatly expand our ability to distinguish electronic states in the surface from those in the selvedge. Possibly it is not too much to hope that the combined use of INS and UPS with incidence angle as an independent variable will give us information on the geometrical extent of surface orbitals, as well as the net electrical charge and the electric potential gradient in the region of the surface in which the orbitals lie.     

Cyclosporin A binding to calmodulin: a possible site of action on T lymphocytes

Cyclosporin A, a potent immunosuppressive agent, has been widely used to treat patients with solid organ transplants. Although its precise mechanism of action is unknown, it appears to inhibit subsets of T lymphocytes at an early stage in cell activation. Fluorescent, fully active derivatives of cyclosporin A and calmodulin, a protein that binds calcium and is therefore essential to normal cell function, were utilized to demonstrate that cyclosporin A binds to calmodulin. Flow cytometry showed that the calmodulin inhibitors R24571 and W-7 competitively inhibited binding of cyclosporin A to cloned T lymphocytes. Cyclosporin A inhibited the calmodulin-dependent activation of phosphodiesterase in a dose-dependent manner. Binding of cyclosporin A to calmodulin may prevent the latter's role in the activation of the second messengers and enzymes required for effective cell proliferation and function in the immune response.     

Autoantibodies to beta 2-adrenergic receptors: a possible cause of adrenergic hyporesponsiveness in allergic rhinitis and asthma

Autoantibodies to beta 2-adrenergic receptors have been identified in the serum of one patient with allergic rhinitis ("hay fever") and two patients with asthma. The antibodies precipitate solubilized dog lung beta receptors in an indirect immunoprecipitation assay and inhibit the specific binding of iodine-125-labeled iodohydroxybenzylpindolol to membrane-associated receptors from dog lung, calf lung, and human placenta. Ligand binding to canine heart beta 1 receptors is not affected by the antibodies.