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—The hypothesis of an oxygen-limited thermal tolerance was tested in the Antarctic teleost Pachycara brachycephalum. With the use of flow-through respirometry, in vivo 31 P-NMR spectroscopy, and MRI, we studied energy metabolism, intracellular pH (pH i), blood flow, and oxygenation between 0 and 13°C under normoxia (PO2: 20.3 to 21.3 kPa) and hyperoxia(More)
The effect of acute increase in temperature on oxygen partial pressure (PO 2) was measured in the gill arches of Atlantic cod Gadus morhua between 10 and 19 C by use of oxygen micro-optodes. Oxygen saturation of the gill blood under control conditions varied between 90 and 15% reflecting a variable percentage of arterial or venous blood in accordance with(More)
Acidification of ocean surface waters by anthropogenic carbon dioxide (CO(2)) emissions is a currently developing scenario that warrants a broadening of research foci in the study of acid-base physiology. Recent studies working with environmentally relevant CO(2) levels, indicate that some echinoderms and molluscs reduce metabolic rates, soft tissue growth(More)
The hypothesis of an oxygen-limited thermal tolerance due to restrictions in cardiovascular performance at extreme temperatures was tested in Atlantic cod, Gadus morhua (North Sea). Heart rate, changes in arterial and venous blood flow, and venous oxygen tensions were determined during an acute temperature change to define pejus ("getting worse")(More)
High-resolution proton magnetic resonance spectroscopy was performed on tissue specimens from 33 patients with astrocytic tumors (22 astrocytomas, 11 glioblastomas) and 13 patients with meningiomas. For all patients, samples of primary tumors and their first recurrences were examined. Increased anaplasia, with respect to malignant transformation, resulting(More)
Temperature-dependent adjustments of intra-cellular pH are thought to play a major role in the maintenance of protein function. Comparative studies were carried out in two species from the same ®sh family (Zoarcidae), the stenothermal Antarctic eelpout (Pachycara brachycephalum) and the eurythermal eel-pout (Zoarces viviparus), to ®nd out whether pH(More)
The cellular background of the drastic drop in metabolic rate and body temperature observed in mammalian hibernation is poorly understood in We applied flow-, T,*-weighted MRI and 3'P-MRS to hibernating European ground squirrels in torpor and during arousal to euthermy, Blood flow was low in arteries supplying the torpid brain, however, T,*-weighted images(More)
Heavy loading, strong RF loss and the skin effect complicate MR investigations in electric conductive, dielectric media. A setup was developed for MR studies on swimming marine fish that reduces these limitations. A birdcage resonator adapted to high loadings was used for signal excitation. An insulated inductive coil (2 cm diameter) was fixed onto the fish(More)
In various phyla of marine invertebrates limited capacities of both ventilatory and circulatory performance were found to set the borders of the thermal tolerance window with limitations in aerobic scope and onset of hypoxia as a first line of sensitivity to both cold and warm temperature extremes. The hypothesis of oxygen limited thermal tolerance has(More)
Climate variability has long been seen to influence the structure and functioning of marine, terrestrial and freshwater ecosystems. Fluctuations in marine communities and populations have been attributed to the impact of decadal-scale variations in the coupled ocean–atmosphere system (Cushing 1982, Beamish 1995, Bakun 1996, O'Brien et al. 2000, Finney et(More)