While the pathogenesis of chronic obstructive pulmonary disease (COPD) is incompletely understood, chronic inflammation is a major factor. In fact, the inflammatory response is abnormal, with CD8+ T-cells, CD68+ macrophages, and neutrophils predominating in the conducting airways, lung parenchyma, and pulmonary vasculature. Elevated levels of the second messenger cAMP can inhibit some inflammat...

The critical cell density for relaying in D. discoideum, N*, has been measured as a function of cell density, N, and time after harvesting, t. It has logarithmic dependence on N for 2.5 X 10(4)/cm2 less than N less than 7.5 X 10(5)/cm2 and saturates for N more than 1.0 X 10(6)/cm2. N* is an increasing function of time after harvesting. The phosphodiesterase (PDE) secretion rate on which N* depe...

While some simulations whose computational work requirements are superlinear in memory requirements have executed at 1 Teraflop/s, simulations of PDE-based systems remain “mired” in the hundreds of Gigaflop/s on the same machines. We briefly review the algorithmic structure of typical PDE-based CFD codes that is responsible for this situation and consider possible architectural and algorithmic ...

This study determined whether phosphodiesterase (PDE) was activated by protein kinase C (PKC) upon kappa-receptor stimulation, and if so, to identify the isozyme. We first studied the effects of trans-(+/-)-3,4-dichloro-N-methyl-N-(2-[1-pyrrolidinyl] cyclohexyl) benzeneacetamide methanesulphonate (U50,488H), a selective kappa-opioid receptor (OR) agonist, and phorbol-12-myristate-13-acetate (PM...

The cGMP phosphodiesterase (PDE) of retinal rod outer segments (ROS) is activated by the GTP-bound form of the G protein, transducin (Gt alpha). This activation can be reversed by the inhibitory gamma subunit of PDE through two distinct mechanisms: acceleration of GTP hydrolysis and direct inactivation independent of GTP hydrolysis. We have found that acceleration of Gt alpha GTPase by PDE gamm...

Drosophila carrying the X-linked mutation dunce (dnc) showed poor learning in a negative reinforcement olfactory conditioning paradigm (Dudai, Y., Y.-N. Jan, D. Byers, W.G. Quinn, and S. Benzer (1976) Proc. Natl. Acad. Sci. U.S.A. 73: 1684-1688). More recently, dnc flies were shown to have reduced activity for one of two cAMP phosphodiesterases (PDEs) present in normal flies, PDE II, whereas PD...