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| 2. |
- Arnemo, Jon, et al.
(författare)
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EFFECT OF ACTIVE COOLING AND alpha-2 ADRENOCEPTOR ANTAGONISM ON CORE TEMPERATURE IN ANESTHETIZED BROWN BEARS (URSUS ARCTOS)
- 2015
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Ingår i: Journal of Zoo and Wildlife Medicine. - 1042-7260 .- 1937-2825. ; 46, s. 279-285
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Tidskriftsartikel (refereegranskat)abstract
- Hyperthermia is a common complication during anesthesia of bears, and it can be life threatening. The objective of this study was to evaluate the effectiveness of active cooling on core body temperature for treatment of hyperthermia in anesthetized brown bears (Ursus arctos). In addition, body temperature after reversal with atipamezole was also evaluated. Twenty-five adult and subadult brown bears were captured with a combination of zolazepam-tiletamine and xylazine or medetomidine. A core temperature capsule was inserted into the bears' stomach or 15 cm into their rectum or a combination of both. In six bears with gastric temperatures >= 40.0 degrees C, an active cooling protocol was performed, and the temperature change over 30 min was analyzed. The cooling protocol consisted of enemas with 2 L of water at approximately 5 degrees C/100 kg of body weight every 10 min, 1 L of intravenous fluids at ambient temperature, water or snow on the paws or the inguinal area, intranasal oxygen supplementation, and removing the bear from direct sunlight or providing shade. Nine bears with body temperature >39.0 degrees C that were not cooled served as control for the treated animals. Their body temperatures were recorded for 30 min, prior to administration of reversal. At the end of the anesthetic procedure, all bears received an intramuscular dose of atipamezole. In 10 bears, deep rectal temperature change over 30 min after administration of atipamezole was evaluated. The active cooling protocol used in hyperthermic bears significantly decreased their body temperatures within 10 min, and it produced a significantly greater decrease in their temperature than that recorded in the control group.
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| 3. |
- Arnemo, Jon, et al.
(författare)
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Effects of different doses of medetomidine and tiletamine-zolazepam on the duration of induction and immobilization in free-ranging yearling brown bears (Ursus arctos)
- 2012
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Ingår i: Canadian Journal of Zoology. - 0008-4301 .- 1480-3283. ; 90, s. 753-757
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Tidskriftsartikel (refereegranskat)abstract
- We compared anesthetic protocols with different doses of tiletamine-zolazepam (TZ) combined with medetomidine (M) for 288 yearling brown bear (Ursus arctos L., 1758) immobilizations with the objective of finding a combination of doses that would provide fast induction with a duration of anesthesia long enough to minimize the need for administering additional drug. The duration of induction time and immobilization was dose-dependent. Increasing the M dose resulted in significantly shorter induction times and a lower probability of giving supplemental drugs. Increasing the TZ dose prolonged duration of anesthesia. For yearling brown bears in Scandinavia, captured shortly after den emergence in April and May, we recommend total dart doses of 1.0-1.66 mg M/dart, plus 62.5-125 mg TZ/dart, depending on the individual requirements for the length and depth of anaesthesia.
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| 4. |
- Arnemo, Jon, et al.
(författare)
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Field Emergencies and Complications
- 2014
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Ingår i: Zoo Animal and Wildlife Immobilization and Anesthesia. - Hoboken, NJ, USA : John Wiley & Sons, Inc.. - 9781118792926 ; , s. 139-147
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 5. |
- Edner, Anna, et al.
(författare)
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Standing sedation with xylazine and reversal with yohimbine in juvenile asian elephants (Elephas maximus)
- 2021
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Ingår i: Journal of Zoo and Wildlife Medicine. - : American Association of Zoo Veterinarians. - 1042-7260 .- 1937-2825. ; 52, s. 437-444
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Tidskriftsartikel (refereegranskat)abstract
- Evaluation and improvement of immobilization methods are important for wildlife welfare and biodiversity conservation. The sedative and physiological effects of xylazinc (50-110 mg per elephant; 0.09-0.15 mg/kg IM) were evaluated in 15 juvenile Asian elephants (Elephas maximus) in Sri Lanka. The time from xylazine injection until first sign of sedation, handling, and reversal with yohimbine (0.009-0.03 mg/kg IV) were recorded. Behavioral signs, level of sedation (no effect, light, moderate, or deep) and response to handling were assessed. Rectal temperature, pulse, and respiratory rates were recorded and arterial blood samples were analyzed 30 and 45 min after xylazine injection. The first sign of sedation occurred within 5-18 min. Standing sedation was induced in all elephants, but the level of sedation varied differently over time for each elephant. Twelve elephants remained standing throughout the sedation period, while 3 elephants became laterally recumbent. Sedative effects included lowered head and trunk, droopy ears, snoring, and penis protrusion. Pulse rate, respiratory rate, and rectal temperature ranged between 30-45 beats/min, 4-12 breaths/min, and 35.6-37.2 degrees C, respectively, at 30 min after xylazine injection, and there were no changes over time. Pulmonary function and acid-base balance were adequate (range partial pressures of arterial oxygen 73-123 mmHg and carbon dioxide 33-52 mmHg, arterial hemoglobin oxygen saturation 96-99%, pH 7.34-7.54, lactate 0.9-2.5 mmol/L). Yohimbine was administered 46-110 min after the injection of xylazine, and the first sign of recovery occurred within 1-4 min. Resedation after reversal with yohimbine was observed in two elephants. In conclusion, xylazine at the doses used induced light to deep sedation with stable physiology and most elephants remained standing.
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| 6. |
- Evans, Alina L., et al.
(författare)
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Capture, Anesthesia, and Disturbance of Free-Ranging Brown Bears (Ursus arctos) during Hibernation
- 2012
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 7:7
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Tidskriftsartikel (refereegranskat)abstract
- We conducted thirteen immobilizations of previously collared hibernating two-to four-year-old brown bears (Ursus arctos) weighing 21-66 kg in central Sweden in winter 2010 and 2011 for comparative physiology research. Here we report, for the first time, an effective protocol for the capture and anesthesia of free-ranging brown bears during hibernation and an assessment of the disturbance the captures caused. Bears were darted in anthill, soil, or uprooted tree dens on eleven occasions, but two bears in rock dens fled and were darted outside the den. We used medetomidine at 0.02-0.06 mg/kg and zolazepam-tiletamine at 0.9-2.8 mg/kg for anesthesia. In addition, ketamine at 1.5 mg/kg was hand-injected intramuscularly in four bears and in six it was included in the dart at 1.1-3.0 mg/kg. Once anesthetized, bears were removed from the dens. In nine bears, arterial blood samples were analyzed immediately with a portable blood gas analyzer. We corrected hypoxemia in seven bears (PaO2 57-74 mmHg) with supplemental oxygen. We placed the bears back into the dens and antagonized the effect of medetomidine with atipamezole. Capturing bears in the den significantly increased the risk of den abandonment. One of twelve collared bears that were captured remained at the original den until spring, and eleven, left their dens (mean +/- standard deviation) 3.2 +/- 3.6 (range 0.5-10.5) days after capture. They used 1.9 +/- 0.9 intermediate resting sites, during 6.2 +/- 7.8 days before entering a new permanent den. The eleven new permanent dens were located 730 +/- 589 m from the original dens. We documented that it was feasible and safe to capture hibernating brown bears, although they behaved differently than black bears. When doing so, researchers should use 25% of the doses used for helicopter darting during the active period and should consider increased energetic costs associated with den abandonment.
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| 8. |
- Fahlman, Åsa, et al.
(författare)
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Adipose-derived stem cells from the brown bear (Ursus arctos) spontaneously undergo chondrogenic and osteogenic differentiation in vitro
- 2011
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Ingår i: Stem Cell Research. - : Elsevier BV. - 1873-5061 .- 1876-7753. ; 7, s. 89-95
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Tidskriftsartikel (refereegranskat)abstract
- In the den, hibernating brown bears do not develop tissue atrophy or organ damage, despite almost no physical activity. Mesenchymal stem cells could play an important role in tissue repair and regeneration in brown bears. Our objective was to determine if adipose tissue-derived stem cells (ASCs) can be recovered from wild Scandinavian brown bears and characterize their differentiation potential. Following immobilization of wild brown bears 7-10 days after leaving the den in mid-April, adipose tissue biopsies were obtained. ASCs were recovered from 6 bears, and shown to be able to undergo adipogenesis and osteogenesis in monolayer cultures and chondrogenesis in pellet cultures. Remarkably, when grown in standard cell culture medium in monolayer cultures, ASCs from yearlings spontaneously formed bone-like nodules surrounded by cartilaginous deposits, suggesting differentiation into osteogenic and chondrogenic lineages. This ability appears to be lost gradually with age. This is the first study to demonstrate stem cell recovery and growth from brown bears, and it is the first report of ASCs spontaneously forming extracellular matrix characteristic of bone and cartilage in the absence of specific inducers. These findings could have implications for the use of hibernating brown bears as a model to study disuse osteoporosis. (C) 2011 Elsevier B.V. All rights reserved.
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| 10. |
- Fahlman, Åsa
(författare)
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Cortisol and corticosterone independence in cortisol-dominant wildlife
- 2012
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Ingår i: General and Comparative Endocrinology. - : Elsevier BV. - 0016-6480 .- 1095-6840. ; 177, s. 113-119
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Tidskriftsartikel (refereegranskat)abstract
- Species have traditionally been defined as cortisol-dominant or corticosterone-dominant, depending on the glucocorticoid that is reported. To assess the degree of covariance versus independence between cortisol and corticosterone, 245 serum samples belonging to 219 individuals from 18 cortisol-dominant, non-domesticated species (6 mammalian orders) were compared by mass spectrometry. In these samples, which were elevated above baseline, concentration ranges were overlapping for cortisol and corticosterone although cortisol was dominant in every sample except one of 17 bighorn sheep with a corticosterone-biased cortisol-to-corticosterone ratio of 0.17. As expected, cortisol and corticosterone were strongly associated among species (r(2) = 0.8; species with high absolute cortisol tend to have high absolute corticosterone concentrations), with wide variation in the species-average cortisol-to-corticosterone ratio (range 7.5-49) and an even wider ratio range across individuals (0.2-341). However, only 9 out of 13 species with >7 individuals showed a positive association between cortisol and corticosterone among individuals, and repeated measures of the cortisol-to-corticosterone ratio within individuals were weakly associated (CV range 3-136%). We conclude that corticosterone, although at lower concentrations, has the potential to signal independently of cortisol, and should be included in integrated endocrine models of stress responses. (C) 2012 Elsevier Inc. All rights reserved.
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