Publications by authors named "Ditte Kristensen"

Article Synopsis
  • Ectothermic vertebrates like ball pythons exhibit changes in ventricular repolarization (notably T-wave polarity) due to fluctuations in body temperature, while mammals maintain stable temperatures with heart rate and sympathetic nervous system activity affecting repolarization.
  • A study using electrocardiograms and epicardial mapping on pythons showed that heating led to T-wave polarity changes, but these changes varied among individuals and were linked to adrenergic signaling rather than temperature alone.
  • Findings suggest that increased sympathetic nervous system activity, facilitated by catecholamines, plays a crucial role in modulating ventricular repolarization in both pythons and mammals, highlighting similar evolutionary mechanisms.
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The electrocardiogram (ECG) reveals that heart chamber activation and repolarization are much faster in mammals and birds compared to ectothermic vertebrates of similar size. Temperature, however, affects electrophysiology of the heart and most data from ectotherms are determined at body temperatures lower than those of mammals and birds. The present manuscript is a review of the effects of temperature on intervals in the ECG of ectothermic and endothermic vertebrates rather than a hypothesis-testing original research article.

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In many seabird studies, single annual proxies of prey abundance have been used to explain variability in breeding performance, but much more important is probably the timing of prey availability relative to the breeding season when energy demand is at a maximum. Until now, intraseasonal variation in prey availability has been difficult to quantify in seabirds. Using a state-of-the-art ocean drift model of larval cod Gadus morhua, an important constituent of the diet of common guillemots Uria aalge in the southwestern Barents Sea, we were able to show clear, short-term correlations between food availability and measurements of the stress hormone corticosterone (CORT) in parental guillemots over a 3-year period (2009-2011).

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This study investigated fiber-type-specific muscle ceramide content in obese subjects and type 2 diabetes patients. Two substudies, one which compared type 2 diabetes patients to both lean- and obese BMI-matched subjects and the other study which compared lean body-matched post-obese, obese, and control subjects, were performed. A fasting blood sample was obtained and plasma insulin and glucose determined.

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