We studied the effects of different classes of inotropic drugs on human working myocardium in vitro that was isolated from the hearts of patients with end-stage heart failure, and compared the responses to these drugs with those noted in muscles from nonfailing control hearts. Although peak isometric force generated in response to increased extracellular calcium reached control levels in the muscles from patients with heart failure, the time course of contraction and rate of relaxation were greatly prolonged. The inotropic effectiveness of the ,B-adrenergic agonist isoproterenol and the phosphodiesterase inhibitors milrinone, caffeine, and isobutylmethylxanthine was markedly reduced in muscles from the patients with heart failure. In contrast, the effectiveness of inotropic stimulation with acetylstrophanthidin and the adenylate cyclase activator forskolin was preserved. After a minimally effective dose of forskolin was given to elevate intracellular cyclic AMP levels, the inotropic responses of muscles from the failing hearts to phosphodiesterase inhibitors were markedly potentiated. These data indicate that an abnormality in cyclic AMP production may be a fundamental defect present in patients with end-stage heart failure that can markedly diminish the effectiveness of agents that depend on generation of this nucleotide for production of a positive inotropic effect.

We tested the hypothesis that intracellular Ca++ ([Ca+Jli)

Self-biased planar millimeter wave notch filters based on magnetostatic wave excitation in barium hexagonal ferrite thin films Appl. Phys. Lett. 97, 173502 (2010); 10.1063/1.3504256Electric detection of the spin-Seebeck effect in ferromagnetic metals (invited)Light-induced generation of pure spin currents in a Pt(2.5 nm)/BaFe 12 O 19 (1.2 lm)/ sapphire(0.5 mm) structure is reported. The BaFe 12 O 19 film had strong in-plane uniaxial anisotropy and was therefore self-biased. Upon exposure to light, a temperature difference (DT) was established across the BaFe 12 O 19 thickness that gave rise to a pure spin current in the Pt via the spin Seebeck effect. Via the inverse spin Hall effect, the spin current produced an electric voltage across one of the Pt lateral dimensions. The voltage varied with time in the same manner as DT and flipped its sign when the magnetization in BaFe 12 O 19 was reversed. V C 2014 AIP Publishing LLC.

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