scholarly journals Evidence that stress-induced changes in surface temperature serve a thermoregulatory function

2019 ◽  
Author(s):  
Joshua K. Robertson ◽  
Gabriela Mastromonaco ◽  
Gary Burness
Keyword(s):  
Surface Temperature ◽  
Ambient Temperature ◽  
Heat Loss ◽  
Thermal Environment ◽  
Dry Heat ◽  
Functional Value ◽  
Region Temperature ◽  
Functional Consequences ◽  
Thermoregulatory Function ◽  
Induced Changes

AbstractChanges in body temperature following exposure to stressors have been documented for nearly two millennia, however, the functional value of this phenomenon is poorly understood. We tested two competing hypotheses to explain stress-induced changes in temperature, with respect to surface tissues. Under the first hypothesis, changes in surface temperature are a consequence of vasoconstriction that occurs to attenuate blood-loss in the event of injury and serves no functional purpose per se; defined as the Haemoprotective Hypothesis. Under the second hypothesis, changes in surface temperature reduce thermoregulatory burdens experienced during activation of a stress response, and thus hold a direct functional value; here, the Thermoprotective Hypothesis. To understand whether stress-induced changes in surface temperature have functional consequences, we tested predictions of the Haemoprotective and Thermoprotective hypotheses by exposing Black-capped Chickadees (n = 20) to rotating stressors across an ecologically relevant ambient temperature gradient, while non-invasively monitoring surface temperature (eye region temperature) using infrared thermography. Our results show that individuals exposed to rotating stressors reduce surface temperature and dry heat loss at low ambient temperature and increase surface temperature and dry heat loss at high ambient temperature, when compared to controls. These results support the Thermoprotective Hypothesis and suggest that changes in surface temperature following stress exposure have functional consequences and are consistent with an adaptation. Such findings emphasize the importance of the thermal environment in shaping physiological responses to stressors in vertebrates, and in doing so, raise questions about their suitability within the context of a changing climate.Summary StatementWe provide empirical evidence for a functional value to stress-induced changes in surface temperature that is consistent with an adaptation, using a temperate endotherm (Black-capped Chickadee) as a model species.

scholarly journals Partial submergence: An undescribed behavioral adjustment for thermoregulation at high ambient temperature in Aeshnidae

2021 ◽  
Vol 24 ◽  
pp. 71-81
Author(s):  
Pierre Deviche
Keyword(s):  
Ambient Temperature ◽  
Heat Loss ◽  
Heat Production ◽  
Sonoran Desert ◽  
Heat Dissipation ◽  
High Ambient Temperature ◽  
Physiological Mechanisms ◽  
Anax Junius ◽  
Daily Difference ◽  
Thermoregulatory Function

Many insects including odonates thermoregulate using a combination of behavioral and physiological mechanisms. At high ambient temperature (Ta), these mechanisms include decreased heat production and increased heat loss. Heat production can be reduced by decreasing activity. Heat loss can be enhanced by perching in a shaded microhabitat where temperature is cooler than in the surrounding environment. Aeshnids, which are intermittent endotherms, increase heat loss at high Ta; also by increasing hemolymph circulation from the thorax, where most metabolic heat is produced, to the abdomen, where it dissipates to the environment by convection. While studying two aeshnid species (Anax junius and Rhionaeschna multicolor) at a Sonoran Desert (Arizona, USA) stream, I observed partially submerged mature individuals of both sexes of these species. This heretofore undescribed behavior was seen only at Ta; ≥ 43 °C and almost exclusively during the hottest part of the day (15:00–17:00 hr), when the daily difference between Ta; and water temperature (Tw) was, on average, largest. A cooling effect of partial submergence behavior on body temperature would, therefore, presumably be most effective also during this period. Several percher species of libellulids were present at the study site. These dragonflies are not known to use endothermy for thermoregulation or to increase hemolymph circulation to the abdomen to dissipate heat at high Ta;, and none was ever observed to partially submerge. It is suggested in aeshnids that partial submergence at high Ta; serves a thermoregulatory function by facilitating body heat dissipation from the abdomen.

RESPIRATORY CONTRIBUTION TO THE THERMAL BALANCE OF THE NEWBORN INFANT UNDER VARIOUS AMBIENT CONDITIONS

PEDIATRICS ◽  
1973 ◽  
Vol 51 (4) ◽  
pp. 641-650
Author(s):  
E. Sulyok ◽  
E. Jéquier ◽  
L. S. Prod'hom
Keyword(s):  
Ambient Temperature ◽  
Heat Loss ◽  
Newborn Infant ◽  
Thermal Environment ◽  
Newborn Infants ◽  
Thermal Balance ◽  
Evaporative Heat Loss ◽  
Ambient Conditions ◽  
Direct Calorimetry ◽  
Respiratory Heat Loss

The influence of environmental humidity and temperature on the thermal balance of 45 full-term newborn infants was studied by direct calorimetry within 24 hours after birth. The respiratory heat loss measured at 32C and 20% relative humidity (RH) represented 9.5% of the total heat production, and it decreased to 2.9% when RH was 80%. In neutral thermal environment (32C, 50% RH), the mean respiratory heat loss was lower than that measured during a warm exposure (36C, 50% RH), in spite of a higher absolute humidity in the latter condition. This suggests that respiration might have a thermoregulatory function during heat exposure in the newborn. Evaporative heat loss from the skin was more elevated than that from the respiratory tract, but it was less sensitive to change in ambient humidity. Convective and radiative heat losses from the skin were inversely related to ambient temperature; similarly, the metabolic rate decreased with increasing ambient temperature up to 36C. This work provides further data on the varying energy exchange between the newborn infant and his environment; it should lead to a more rational planning of infant care and caloric requirements and demonstrates the important effects of different environmental conditions on the newborn infant.

scholarly journals Evidence that stress-induced changes in surface temperature serve a thermoregulatory function

2020 ◽  
Vol 223 (4) ◽  
pp. jeb213421 ◽  
Author(s):  
Joshua K. Robertson ◽  
Gabriela Mastromonaco ◽  
Gary Burness
Keyword(s):  
Surface Temperature ◽  
Thermoregulatory Function ◽  
Induced Changes

scholarly journals COVID-19 global pandemic planning: Dry heat incubation and ambient temperature fail to consistently inactivate SARS-CoV-2 on N95 respirators

2020 ◽  
pp. 153537022097781
Author(s):  
Douglas J Perkins ◽  
Robert A Nofchissey ◽  
Chunyan Ye ◽  
Nathan Donart ◽  
Alison Kell ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
Personal Protective Equipment ◽  
Healthcare Personnel ◽  
Protective Equipment ◽  
Experimental Conditions ◽  
Dry Heat ◽  
Global Pandemic ◽  
Individual Site ◽  
Pandemic Planning ◽  
N95 Respirators

The ongoing pandemic of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has placed a substantial strain on the supply of personal protective equipment, particularly the availability of N95 respirators for frontline healthcare personnel. These shortages have led to the creation of protocols to disinfect and reuse potentially contaminated personal protective equipment. A simple and inexpensive decontamination procedure that does not rely on the use of consumable supplies is dry heat incubation. Although reprocessing with this method has been shown to maintain the integrity of N95 respirators after multiple decontamination procedures, information on the ability of dry heat incubation to inactivate SARS-CoV-2 is largely unreported. Here, we show that dry heat incubation does not consistently inactivate SARS-CoV-2-contaminated N95 respirators, and that variation in experimental conditions can dramatically affect viability of the virus. Furthermore, we show that SARS-CoV-2 can survive on N95 respirators that remain at room temperature for at least five days. Collectively, our findings demonstrate that dry heat incubation procedures and ambient temperature for five days are not viable methods for inactivating SARS-CoV-2 on N95 respirators for potential reuse. We recommend that decontamination procedures being considered for the reuse of N95 respirators be validated at each individual site and that validation of the process must be thoroughly conducted using a defined protocol.

Seasonal changes in the body surface temperature of Hanwoo (Bos taurus coreanae) steers

2014 ◽  
Vol 54 (9) ◽  
pp. 1476 ◽  
Author(s):  
N. Y. Kim ◽  
S. J. Kim ◽  
J. H. Park ◽  
M. R. Oh ◽  
S. Y. Jang ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Ambient Temperature ◽  
Body Surface ◽  
Seasonal Changes ◽  
Bos Taurus ◽  
The Body ◽  
Body Regions ◽  
Extreme Cold ◽  
Body Surface Temperature ◽  
Average Body

The present study aimed to gather basic information on measuring body surface temperature (BST) of cattle by using infrared thermography (IRT) and find out whether BST measurement is a useful method to detect thermal balance of livestock. Twenty-seven Hanwoo steers were examined in a field trial. The BST of five body regions (eye, nose, horn, ear, rear) was measured five times daily, with three replicates, during 3 days each season. Body surface temperature of cattle is directly affected by ambient temperature and humidity, and showed different ranges for each region. The BSTs of nose, horns and ears were significantly (P < 0.05) lower than those of eyes and rear area. Rear-area BST was significantly lower than eye-area BST when the ambient temperature was low (P < 0.05). Eye BST (EBST) was highest (P < 0.05) and the least variable of all BSTs measured. Therefore, the eye area of cattle was the most thermostable part of the body. There were significant (P < 0.05) differences among seasonal EBSTs of steers. The EBST range was highest in the summer (37.9–42.2°C), followed by autumn (34.3–37.4°C), spring (33.8–36.5°C) and winter (29.8–32.6°C). During extreme cold, EBST showed a large standard deviation. During conditions of extreme heat, EBST was above the average body temperature of cattle. The results of the present study indicated that BST well reflects the thermal circumstances surrounding animals and may be used as one of the effective tools for precision cattle farming.

Toe Temperatures During Dartmoor Training

1988 ◽  
Vol 74 (3) ◽  
pp. 181-186
Author(s):  
S. P. L. Travis
Keyword(s):  
Surface Temperature ◽  
Ambient Temperature ◽  
Skin Temperature ◽  
Air Temperature ◽  
Factors Associated ◽  
Recording Period ◽  
Exposure To Cold ◽  
Main Factors ◽  
Minimum Air Temperature

AbstractThe surface temperature of eight Royal Marine recruits was monitored in the field during Autumn training on Dartmoor (minimum air temperature 4.5°C). The lowest skin temperature recorded was 6.1°C. One subject experienced a toe temperature below 10° for 5.5 hours and below 15°C for 12.6 hours during a 24 hour recording period. Ambient temperature and inactivity during exposure to cold were the main factors associated with low toe temperatures but individual responses varied widely.

scholarly journals The thermogenic effect of nesfatin-1 requires recruitment of the melanocortin system

2017 ◽  
Vol 235 (2) ◽  
pp. 111-122 ◽  
Author(s):  
Riccardo Dore ◽  
Luka Levata ◽  
Sogol Gachkar ◽  
Olaf Jöhren ◽  
Jens Mittag ◽  
...  
Keyword(s):  
Energy Expenditure ◽  
Heat Loss ◽  
Central Administration ◽  
Melanocortin System ◽  
Direct Calorimetry ◽  
Iodothyronine Deiodinase ◽  
Interscapular Brown Adipose Tissue ◽  
Peripheral Tissues ◽  
Dry Heat ◽  
Brown Adipose

Nesfatin-1 is a bioactive polypeptide expressed both in the brain and peripheral tissues and involved in the control of energy balance by reducing food intake. Central administration of nesfatin-1 significantly increases energy expenditure, as demonstrated by a higher dry heat loss; yet, the mechanisms underlying the thermogenic effect of central nesfatin-1 remain unknown. Therefore, in this study, we sought to investigate whether the increase in energy expenditure induced by nesfatin-1 is mediated by the central melanocortin pathway, which was previously reported to mediate central nesfatin-1´s effects on feeding and numerous other physiological functions. With the application of direct calorimetry, we found that intracerebroventricular nesfatin-1 (25 pmol) treatment increased dry heat loss and that this effect was fully blocked by simultaneous administration of an equimolar dose of the melanocortin 3/4 receptor antagonist, SHU9119. Interestingly, the nesfatin-1-induced increase in dry heat loss was positively correlated with body weight loss. In addition, as assessed with thermal imaging, intracerebroventricular nesfatin-1 (100 pmol) increased interscapular brown adipose tissue (iBAT) as well as tail temperature, suggesting increased heat production in the iBAT and heat dissipation over the tail surface. Finally, nesfatin-1 upregulated pro-opiomelanocortin and melanocortin 3 receptor mRNA expression in the hypothalamus, accompanied by a significant increase in iodothyronine deiodinase 2 and by a nonsignificant increase in uncoupling protein 1 and peroxisome proliferator-activated receptor gamma coactivator-1 alpha mRNA in the iBAT. Overall, we clearly demonstrate that nesfatin-1 requires the activation of the central melanocortin system to increase iBAT thermogenesis and, in turn, overall energy expenditure.

Energy balance in ovariectomized rats with and without estrogen replacement

1980 ◽  
Vol 238 (5) ◽  
pp. R400-R405 ◽  
Author(s):  
M. L. Laudenslager ◽  
C. W. Wilkinson ◽  
H. J. Carlisle ◽  
H. T. Hammel
Keyword(s):  
Energy Balance ◽  
Heat Loss ◽  
Body Mass ◽  
Heat Production ◽  
Hormone Treatment ◽  
Ovariectomized Rats ◽  
Dark Phase ◽  
Evaporative Heat Loss ◽  
Estrogen Replacement ◽  
Dry Heat

The effect of estrogen replacement on several parameters of energy balance was investigated in ovariectomized rats tested during the dark phase of their diurnal cycle. Estrogen replacement, either as 17 beta-estradiol or beta-estradiol-3-benzoate via subcutaneous Silastic capsules, was associated with elevated rates of heat production and dry heat loss relative to untreated ovariectomized controls. Estrogen treatment reduced body mass and retarded fur growth. The effects of estrogen replacement on heat production and dry heat loss could not be attributed to these differences in body mass and fur growth or locomotor activity. Estrogen replacement had no effect on rate of evaporative heat loss. If estrogen replacement was delayed 75 days following ovariectomy, the increase in heat production and dry heat loss was not observed. There was no effect of the hormone treatment on rectal temperature. It was concluded that either heat production was elevated, with dry heat loss increased to compensate for the additional thermal load, or dry heat loss was accelerated with heat production elevated in compensation.

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