Amy Hewitt

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The responses of cultured chick embryo retinal neurons to several extracellular matrix molecules are described. Retinal cell suspensions in serum-free medium containing the "N1" supplement (J. E. Bottenstein, S. D. Skaper, S. Varon, and J. Sato, 1980, Exp. Cell Res. 125, 183-190) were seeded on tissue culture plastic surfaces pretreated with polyornithine(More)
The astrocyte-neuronal lactate-shuttle hypothesis posits that lactate released from astrocytes into the extracellular space is metabolized by neurons. The lactate released should alter extracellular pH (pHe), and changes in pH in central chemosensory regions of the brainstem stimulate ventilation. Therefore, we assessed the impact of disrupting the lactate(More)
It is well established that many types of cells are dependent on trophic factors for their survival. We are investigating whether photoreceptor survival may also be dependent upon such a factor, as well as the possibility that the interphotoreceptor matrix (IPM), which lies between the outer retina and the RPE, may be a source of photoreceptor(More)
tested the hypothesis that carbenoxolone, a pharmacological inhibitor of gap junctions , would reduce the ventilatory response to CO2 when focally perfused within the retrotrapezoid nucleus (RTN). We tested this hypothesis by measuring minute ventilation (VE), tidal volume (VT), and respiratory frequency (FR) responses to increasing concentrations of(More)
We tested the hypothesis that focally perfusing carbenoxolone, which blocks gap junctions, into the nucleus tractus solitarius (NTS) would reduce the ventilatory response to CO(2). We measured minute ventilation (V(E)), tidal volume (V(T)) and respiratory frequency (F(R)) responses to increasing concentrations of inspired CO(2) (F(I)(CO(2) = 0-8%) in rats(More)
Bruch's membrane may provide a selective filtration barrier for nutrients coming from the choriocapillaris to the outer retina. Because proteoglycans have been shown to have structural and filtration properties in other tissues, we have been investigating the deposition of newly synthesized proteoglycans into Bruch's membrane and how these may be affected(More)
1. In recent years, a number of histochemical and immunocytochemical studies have suggested that proteoglycans, particularly those in the interphotoreceptor matrix, exhibit altered distributions in several murine models for retinal degenerations. We are using a cell culture system to characterize the proteoglycans synthesized by neurons and photoreceptors(More)
Macular degeneration associated with age and drusen, an important cause of visual loss, is associated clinically with alterations in the retinal pigmented epithelium. Because the pigmented epithelium is a copper-rich tissue with antioxidant properties, the copper economy in patients and controls were studied by measuring ceruloplasmin. Ceruloplasmin, a(More)
Epiretinal membrane formation in the posterior pole is an almost constant feature of eyes with retinitis pigmentosa. Using a modified direct immunofluorescence reaction, we demonstrated a strong reaction with antilaminin in a band-like pattern on the inner retinal surface of 3 eyes with retinitis pigmentosa. There were also strongly-laminin-positive(More)
The size increase of skin epithelial cells during aging is well-known. Here we demonstrate that treatment of aging cells with cytochalasin B substantially decreases cell size. This decrease was demonstrated on a mouse model and on human skin cells in vitro. Six nude mice were treated by topical application of cytochalasin B on skin of the dorsal left(More)