John D. Morgan

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Sturgeons are among the most CO2 tolerant of fishes investigated to date. However, the basis of this exceptional CO2 tolerance is unknown. Here, white sturgeon, Acipenser transmontanus, were exposed to elevated CO2 to investigate the mechanisms associated with short-term hypercarbia tolerance. During exposure to 1.5 kPa Pco2, transient blood pH(More)
We tested the hypothesis that nutritional state affects seawater acclimation by transferring either fed or fooddeprived (2 weeks) male tilapia (Oreochromis mossambicus) from fresh water to full-strength sea water. Fooddeprivation resulted in a significant increase in plasma concentrations of Na+, Cl−, cortisol, glucose, total amino acid, glutamate, serine(More)
In marine teleost fishes, the gill mitochondria-rich cells (MRCs) are responsible for NaCl elimination; however, in elasmobranch fishes, the specialized rectal gland is considered to be the most important site for salt secretion. The role of the gills in elasmobranch ion regulation, although clearly shown to be secondary, is not well characterized. In the(More)
PURPOSE To investigate ammonia and glutamine levels in valproate (VPA)-related hyperammonemic encephalopathy (VHE). METHODS We reviewed the medical records and EEG recordings of seven adults diagnosed with VHE. RESULTS Venous ammonia levels were elevated in five (71%) of the seven patients. Elevated serum or cerebrospinal fluid (CSF) glutamine levels(More)
PURPOSE To determine whether the specific location of electrographic seizure onset in the temporal lobe is related to hippocampal pathology in temporal lobe epilepsy (TLE). METHODS Consecutive presurgical patients with scalp EEG-video evidence of TLE and no or mild hippocampal atrophy (HA) on magnetic resonance imaging (MRI) were prospectively studied by(More)
The influence of cortisol on oxygen consumption and osmoregulatory variables was examined in coastal cutthroat trout (Oncorhynchus clarki clarki) parr kept in fresh water (FW) and transferred to seawater (SW). Intraperitoneal implants containing cortisol (50 μg g−1) in vegetable oil resulted in elevated plasma cortisol titres similar to those observed in(More)
Migratory fishes encounter a variety of environmental conditions, including changes in salinity, temperature and dissolved gases, and it is important to understand how these fishes are able to acclimate to multiple environmental stressors. The gill is the primary site of both acid-base balance and ion regulation in fishes. Many ion transport mechanisms(More)
[PDF] [Full Text] [Abstract] , January 8, 2001; 204 (15): 2691-2698. J. Exp. Biol. A. Shingles, D. J. McKenzie, E. W. Taylor, A. Moretti, P. J. Butler and S. Ceradini (Oncorhynchus mykiss) Effects of sublethal ammonia exposure on swimming performance in rainbow trout [PDF] [Full Text] [Abstract] , January 1, 2005; 85 (1): 97-177. Physiol Rev D. H.(More)
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