Josef P Clark

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Light information reaches the suprachiasmatic nucleus (SCN) through a subpopulation of retinal ganglion cells. Previous work raised the possibility that brain-derived neurotrophic factor (BDNF) and its high-affinity tropomyosin-related receptor kinase may be important as modulators of this excitatory input into the SCN. In order to test this possibility, we(More)
Piwi proteins and Piwi-interacting RNAs (piRNAs) repress transposable elements (TEs) from mobilizing in gonadal cells. To determine the spectrum of piRNA-regulated targets that may extend beyond TEs, we conducted a genome-wide survey for transcripts associated with PIWI and for transcripts affected by PIWI knockdown in Drosophila ovarian somatic sheet (OSS)(More)
NZB x NZW (NZB x W) F1 hybrid mice spontaneously develop a disease most prominently characterized by immune complex glomerulonephritis (GN), which seems to be associated with both antibodies to DNA and to the serum retroviral envelope glycoprotein, gp70. To evaluate the contribution of each of these autoimmune responses to the pathogenesis of the GN, we(More)
Although Piwi proteins and Piwi-interacting RNAs (piRNAs) genetically repress transposable elements (TEs), it is unclear how the highly diverse piRNA populations direct Piwi proteins to silence TE targets without silencing the entire transcriptome. To determine the capacity of piRNA-mediated silencing, we introduced reporter genes into Drosophila OSS cells,(More)
1. Membrane potential was recorded intracellularly by micro-electrode in separated longitudinal muscle of guinea-pig ileum. Electrotonic potentials were evoked in longitudinal strips by passing current between large external electrodes in the partition chamber.2. Histamine increased the frequency of action potential discharge at low concentrations and(More)
1 Depolarizations were recorded intracellularly in smooth muscle from the taenia of the guinea-pig caecum in response to the iontophoretic application of acetylcholine, carbachol, oxotremorine-M, methylfurmethide, hexyl trimethylammonium and tetramethylammonium (TMA). 2 No differences between the iontophoretic responses to agonists stable to cholinesterase(More)
1. Shortening and rate of loss of (42)K were studied in strips of longitudinal muscle taken from guinea-pig ileum.2. Carbachol, histamine and raising the external potassium concentration, [K(+)](o), to 120 mm in the presence of atropine caused equal maximal shortenings of the muscle, but unequal maximal increases in (42)K efflux: maximal (42)K effluxes(More)
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