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https://www.readbyqxmd.com/read/28332020/temperature-effects-on-the-activity-shape-and-storage-of-platelets-from-13-lined-ground-squirrels
#1
Scott Cooper, Sarah Lloyd, Anthony Koch, Xingxing Lin, Katie Dobbs, Thomas Theisen, Matt Zuberbuehler, Kaley Bernhardt, Michael Gyorfi, Tanner Tenpas, Skyler Hying, Sarah Mortimer, Christine Lamont, Marcus Lehmann, Keith Neeves
The objective of this study is to determine how a hibernating mammal avoids the formation of blood clots under periods of low blood flow. A microfluidic vascular injury model was performed to differentiate the effects of temperature and shear rate on platelet adhesion to collagen. Human and ground squirrel whole blood was incubated at 15 or 37 °C and then passed through a microfluidic chamber over a 250-µm strip of type I fibrillar collagen at that temperature and the shear rates of 50 or 300 s(-1) to simulate torpid and aroused conditions, respectively...
March 23, 2017: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/28332019/comparative-tissue-transcriptomics-highlights-dynamic-differences-among-tissues-but-conserved-metabolic-transcript-prioritization-in-preparation-for-arousal-from-torpor
#2
Lori K Bogren, Katharine R Grabek, Gregory S Barsh, Sandra L Martin
During the hibernation season, 13-lined ground squirrels spend days to weeks in torpor with body temperatures near freezing then spontaneously rewarm. The molecular drivers of the drastic physiological changes that orchestrate and permit torpor are not well understood. Although transcription effectively ceases at the low body temperatures of torpor, previous work has demonstrated that some transcripts are protected from bulk degradation in brown adipose tissue (BAT), consistent with the importance of their protein products for metabolic heat generation during arousal from torpor...
March 23, 2017: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/28332018/seasonal-loss-and-resumption-of-circadian-rhythms-in-hibernating-arctic-ground-squirrels
#3
Cory T Williams, Maya Radonich, Brian M Barnes, C Loren Buck
Circadian clocks are near universal among organisms and play a key role in coordinating physiological and metabolic functions to anticipate or coincide with predictable daily changes in the physical and social environment. However, whether circadian rhythms persist and are functionally important during hibernation in all mammals is currently unclear. We examined whether circadian rhythms of body temperature (T b) persist during multi-day, steady-state torpor and investigated the association between timing of animal emergence, exposure to light, and resumption of activity and T b rhythms in free-living and captive male arctic ground squirrels...
March 22, 2017: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/28330964/thermoregulatory-inversion-a-novel-thermoregulatory-paradigm
#4
Domenico Tupone, Georgina Cano, Shaun F Morrison
To maintain core body temperature in mammals, the normal CNS thermoregulatory reflex networks produce an increase in brown adipose tissue (BAT) thermogenesis in response to skin cooling, and an inhibition of the sympathetic outflow to BAT during skin rewarming. In contrast, these normal thermoregulatory reflexes appear to be inverted in hibernation/torpor: thermogenesis is inhibited during exposure to a cold environment, allowing dramatic reductions in core temperature and metabolism, and thermogenesis is activated during skin rewarming, contributing to a return of normal body temperature...
March 22, 2017: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
https://www.readbyqxmd.com/read/28324159/hibernation-based-blood-loss-therapy-increases-survivability-of-lethal-hemorrhagic-shock-in-rats
#5
Cecilia E Perez de Lara Rodriguez, Lester R Drewes, Matthew T Andrews
A small-volume (1 ml/kg) resuscitation fluid based on metabolic adaptations in hibernating mammals was optimized using a rat model of hemorrhagic shock. A previous study of this therapy tested only one concentration of three specific components: 4 M D-stereoisomer of beta-hydroxybutyrate (BHB), 43 mM melatonin, and 20% DMSO. In this study, we considered the range of concentrations of BHB and melatonin seen during the physiological extremes of rapid arousal from hypothermic torpor in natural hibernators and applied these to the non-hibernating Sprague-Dawley rat model...
March 21, 2017: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/28324158/the-influence-of-sex-and-diet-on-the-characteristics-of-hibernation-in-syrian-hamsters
#6
Marie Trefna, Maaike Goris, Cynthia M C Thissen, Vera A Reitsema, Jojanneke J Bruintjes, Edwin L de Vrij, Hjalmar R Bouma, Ate S Boerema, Robert H Henning
Research on deep hibernators almost exclusively uses species captured from the wild or from local breeding. An exception is Syrian hamster (Mesocricetus auratus), the only standard laboratory animal showing deep hibernation. In deep hibernators, several factors influence hibernation quality, including body mass, sex and diet. We examined hibernation quality in commercially obtained Syrian hamsters in relation to body mass, sex and a diet enriched in polyunsaturated fatty acids. Animals (M/F:30/30, 12 weeks of age) were obtained from Harlan (IN, USA) and individually housed at 21 °C and L:D 14:10 until 20 weeks of age, followed by L:D 8:16 until 27 weeks...
March 21, 2017: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/28322600/renal-mitochondrial-response-to-low-temperature-in-non-hibernating-and-hibernating-species
#7
George J Dugbartey, Maarten C Hardenberg, Wendelinde F Kok, Ate Boerema, Hannah V Carey, James Staples, Robert H Henning, Hjalmar Bouma
SIGNIFICANCE: Therapeutic hypothermia is commonly applied to limit ischemic injury in organ transplantation, during cardiac and brain surgery and after cardiopulmonary resuscitation. In these procedures, the kidneys are particularly at risk for ischemia/reperfusion injury (IRI), likely due to their high rate of metabolism. Although hypothermia mitigates ischemic kidney injury, it is not a panacea. Residual mitochondrial failure is thought to be a key event triggering loss of cellular homeostasis, and potentially cell death...
March 21, 2017: Antioxidants & Redox Signaling
https://www.readbyqxmd.com/read/28321493/the-costs-of-locomotor-activity-maximum-body-temperatures-and-the-use-of-torpor-during-the-active-season-in-edible-dormice
#8
Claudia Bieber, Jessica S Cornils, Franz Hoelzl, Sylvain Giroud, Thomas Ruf
Measuring T b during the active season can provide information about the timing of reproduction and the use of short bouts of torpor and may be used as a proxy for the locomotor activity of animals (i.e., maximum T b). This kind of information is especially important to understand life-history strategies and energetic costs and demands in hibernating mammals. We investigated T b throughout the active season in edible dormice (Glis glis), since they (i) have an expensive arboreal life-style, (ii) are known to show short bouts of torpor, and (iii) are adapted to pulsed resources (mast of beech trees)...
March 21, 2017: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/28300925/early-malignant-syphilis
#9
Yara Martins Ortigosa, Paulo Salomão Bendazzoli, Angela Marques Barbosa, Luciena Cegatto Martins Ortigosa
Early malignant syphilis is a rare and severe variant of secondary syphilis. It is clinically characterized by lesions, which can suppurate and be accompanied by systemic symptoms such as high fever, asthenia, myalgia, and torpor state. We report a diabetic patient with characteristic features of the disease showing favorable evolution of the lesions after appropriate treatment.
September 2016: Anais Brasileiros de Dermatologia
https://www.readbyqxmd.com/read/28283794/the-role-of-basking-in-the-development-of-endothermy-and-torpor-in-a-marsupial
#10
Chris B Wacker, Bronwyn M McAllan, Gerhard Körtner, Fritz Geiser
Marsupials have a slow rate of development and this allows a detailed examination of thermoregulatory developmental changes and stages. We quantified the cooling rates of marsupial dunnarts (Sminthopsis crassicaudata) at 40-56 days (d) old, and torpor and basking behaviour in animals given the option to bask in four age groups from 60 to 150 d. The development of thermoregulation was a continuum, but was characterised by three major thermoregulatory stages: (1) at 40 d, animals were unable to maintain a constant high body temperature during short-term cold exposure; (2) at 60 d, animals could maintain a high T b for the first part of the night at an ambient temperature of 15...
March 10, 2017: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/28257856/the-role-of-global-histone-post-translational-modifications-during-mammalian-hibernation
#11
Shannon N Tessier, Bryan E Luu, Jeffrey C Smith, Kenneth B Storey
Mammalian hibernators must cope with hypothermia, ischemia-reperfusion, and finite fuel reserves during days or weeks of continuous torpor. One means of lowering ATP demands during hibernation involves substantial transcriptional controls. The present research analyzed epigenetic regulatory factors as a means of achieving transcriptional control over cycles of torpor-arousal. This study analyzes differential regulation of select histone modifications (e.g. phosphorylation, acetylation, methylation), and identifies post-translational modifications on purified histones using mass spectrometry from thirteen-lined ground squirrels (Ictidomys tridecemlineatus)...
February 28, 2017: Cryobiology
https://www.readbyqxmd.com/read/28250178/effect-of-diet-quality-and-ambient-temperature-on-the-use-of-torpor-by-two-species-of-neotropical-nectar-feeding-bats
#12
Jorge Ayala-Berdon, Rommy Vázquez-Fuerte, René Beamonte-Barrientos, Jorge E Schondube
Neotropical bats use torpor as a strategy to save energy when they experience a low energy intake and/or low ambient temperature (Ta). Digestive physiology limits the energy intake of several glossophaginid bats, and could play an important role in the onset of torpor in these tropical animals. We measured the effect that diet quality and Ta had on the use of torpor by the nectar-feeding bats Glossophaga soricina and Leptonycteris yerbabuenae Captive bats were fed with 5% (low) or 35% (high) sucrose solutions while exposed to two different Ta (17...
March 1, 2017: Journal of Experimental Biology
https://www.readbyqxmd.com/read/28213638/hung-out-to-dry-intraspecific-variation-in-water-loss-in-a-hibernating-bat
#13
Brandon J Klüg-Baerwald, R Mark Brigham
Hibernation is a period of water deficit for some small mammals, and humidity strongly influences hibernation patterns. Dry conditions reduce length of torpor bouts, stimulate arousals, and decrease overwinter survival. To mitigate these effects, many small mammals hibernate in near saturated (100% RH) conditions. However, big brown bats (Eptesicus fuscus) hibernate in a wider variety of conditions and tolerate lower humidity than most other bats. To assess arid tolerance in this species, we compared torpid metabolic rates (TMR) and rates of total evaporative water loss (TEWL) between two populations of E...
April 2017: Oecologia
https://www.readbyqxmd.com/read/28210076/potential-role-of-the-gut-microbiota-in-synthetic-torpor-and-therapeutic-hypothermia
#14
REVIEW
Claudia Sisa, Silvia Turroni, Roberto Amici, Patrizia Brigidi, Marco Candela, Matteo Cerri
Therapeutic hypothermia is today used in several clinical settings, among them the gut related diseases that are influenced by ischemia/reperfusion injury. This perspective paved the way to the study of hibernation physiology, in natural hibernators, highlighting an unexpected importance of the gut microbial ecosystem in hibernation and torpor. In natural hibernators, intestinal microbes adaptively reorganize their structural configuration during torpor, and maintain a mutualistic configuration regardless of long periods of fasting and cold temperatures...
January 21, 2017: World Journal of Gastroenterology: WJG
https://www.readbyqxmd.com/read/28179513/immune-responses-in-hibernating-little-brown-myotis-myotis-lucifugus-with-white-nose-syndrome
#15
T M Lilley, J M Prokkola, J S Johnson, E J Rogers, S Gronsky, A Kurta, D M Reeder, K A Field
White-nose syndrome (WNS) is a fungal disease responsible for decimating many bat populations in North America. Pseudogymnoascus destructans (Pd), the psychrophilic fungus responsible for WNS, prospers in the winter habitat of many hibernating bat species. The immune response that Pd elicits in bats is not yet fully understood; antibodies are produced in response to infection by Pd, but they may not be protective and indeed may be harmful. To understand how bats respond to infection during hibernation, we studied the effect of Pd inoculation on the survival and gene expression of captive hibernating Myotis lucifugus with varying pre-hibernation antifungal antibody titres...
February 8, 2017: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/28168294/different-effects-of-sleep-deprivation-and-torpor-on-eeg-slow-wave-characteristics-in-djungarian-hamsters
#16
V V Vyazovskiy, S Palchykova, P Achermann, I Tobler, T Deboer
No abstract text is available yet for this article.
February 7, 2017: Cerebral Cortex
https://www.readbyqxmd.com/read/28100803/a-new-cue-for-torpor-induction-charcoal-ash-and-smoke
#17
Clare Stawski, Julia Nowack, Gerhard Körtner, Fritz Geiser
Recent work has shown that the use of torpor for energy conservation increases after forest fires in heterothermic mammals, probably in response to the reduction of food. However, the specific environmental cues for this increased torpor expression remain unknown. It is possible that smoke and the novel substrate of charcoal and ash act as signals for an impending period of starvation requiring torpor. We therefore tested the hypothesis that the combined cues of smoke, a charcoal/ash substrate and food shortage will enhance torpor expression in a small forest-dwelling marsupial, the yellow-footed antechinus (Antechinus flavipes), because like other animals that live in fire-prone habitats they must effectively respond to fires to ensure survival...
January 15, 2017: Journal of Experimental Biology
https://www.readbyqxmd.com/read/28100794/charred-remains-trigger-torpor-in-antechinus-survivors
#18
Kathryn Knight
No abstract text is available yet for this article.
January 15, 2017: Journal of Experimental Biology
https://www.readbyqxmd.com/read/28077390/reversible-temperature-dependent-differences-in-brown-adipose-tissue-respiration-during-torpor-in-a-mammalian-hibernator
#19
Sarah Victoria McFarlane, Katherine E Mathers, James F Staples
While seasonal modifications of brown adipose tissue (BAT) in hibernators are well documented, we know little about functional regulation of BAT in different phases of hibernation. In the 13-lined ground squirrel, liver mitochondrial respiration is suppressed by up to 70% during torpor. This suppression is reversed during arousal an°°d interbout euthermia (IBE), and corresponds with patterns of maximal activities of electron transport system (ETS) enzymes. Uncoupling of BAT mitochondria is controlled by free-fatty acid release stimulated by sympathetic activation of adipocytes, so we hypothesized that further regulation at the level of the ETS would be of little advantage...
January 11, 2017: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
https://www.readbyqxmd.com/read/28077389/enhanced-oxidative-capacity-of-ground-squirrel-brain-mitochondria-during-hibernation
#20
Mallory A Ballinger, Christine Schwartz, Matthew T Andrews
During hibernation, thirteen-lined ground squirrels (Ictidomys tridecemlineatus) regularly cycle between bouts of torpor and interbout arousal (IBA).  Most of the brain is electrically quiescent during torpor, but regains activity quickly upon arousal to IBA resulting in extreme oscillations in energy demand during hibernation.  We predicted increased functional capacity of brain mitochondria during hibernation compared to spring to accommodate the variable energy demands of hibernation.  To address this hypothesis, we examined mitochondrial bioenergetics in the ground squirrel brain across three time points: spring (SP), torpor (TOR), and IBA...
January 11, 2017: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
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