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PURPOSE To test the hypothesis that high-resolution (23.4 microm intraretinal resolution) manganese-enhanced magnetic resonance imaging (MEMRI) can be used to noninvasively and simultaneously record from distinct layers of the rat retina cellular demand for ions associated with functional adaptation. METHODS In control rats, high-resolution images were(More)
PURPOSE To test the hypothesis that in experimental retinopathy of prematurity (ROP), retinal neovascularization (NV) and vessel tortuosity have distinct spatial and temporal links with receptor and postreceptor ion demand. METHODS Newborn rats were raised in either room air (controls) or variable oxygen (50%/10% [50/10]). After 14 days, 50/10 rats were(More)
Cortical responses to visual stimulation have been studied extensively in the rodent, but often require post-stimulation ex vivo examination of the tissue. Here, we test the hypothesis that visual stimulus-dependent cortical activity from awake and free-moving rats can be encoded following systemically administered MnCl(2), and activity subsequently readout(More)
PURPOSE To test the hypothesis that breathing carbogen (95% O2-5% CO2) oxygenates the inner retina better than breathing 100% oxygen using an magnetic resonance imaging (MRI) method that noninvasively measures inner retinal oxygenation in normal adult and newborn rats. METHODS Urethane-anesthetized adult and newborn (day 18) rats were studied. Sequential(More)
PURPOSE To test the hypothesis that after supplemental oxygen recovery (SOR) in the newborn rat model of retinopathy of prematurity (ROP) the preretinal neovascular (NV) incidence and severity are decreased and the panretinal oxygenation ability is improved. METHODS Newborn rats were first raised in either room air (controls) or variable oxygen (50%/10%)(More)
The purpose of this study was to examine the effects of acute ischemia and reperfusion on blood-retinal barrier (BRB) function in the rabbit eye. Hydrostatic pressure (140 mmHg) was used to create total retinal ischemia for intervals of 20, 40, 60, 80 or 100 min in the rabbit eye. The location, size and permeability-surface-area product normalized to the(More)
PURPOSE The application of manganese-enhanced MRI (MEMRI) to measure retinal function in humans is unclear. To begin to address this gap, we tested the hypothesis that an FDA-approved manganese-based MRI contrast agent, Teslascan, is useful for measuring functional intraretinal ionic regulation. METHODS Anesthetized dark- or light-adapted male healthy(More)
Previous studies have relied on various electrodes or probes to monitor preretinal oxygen tension in an effort to gain insight into retinal oxygenation. In order to corroborate and extend the results of such studies, we developed a relatively non-invasive method of determining preretinal oxygen tension using 19F nuclear magnetic resonance (NMR)(More)
PURPOSE NH4Cl gavage in the neonatal rat produces a metabolic acidosis-induced retinopathy which serves as a model for retinopathy of prematurity (ROP). Acetazolamide induces a metabolic acidosis via an alternative biochemical mechanism (bicarbonate loss versus hydrogen ion load). In the present study, the following hypothesis was tested:(More)
The MRI signal enhancement in a breast tumor, measured as a function of time after a bolus injection of Gd-DTPA, may contain enough information to differentiate malignant from benign tissue. We find a physiological model for measuring capillary permeability and leakage space (P. S. Tofts, A. G. Kermode, measurement of the blood-brain barrier permeability(More)