The Effects of Panax ginseng and Panax quinquefolius on Thermoregulation in Animal Models

PubMed Central

Hong, Bin Na; Do, Moon Ho; Her, You Ri

2015-01-01

We devised a study using animal models of hyperthermia and hypothermia and also attempted to accurately assess the effects of Panax ginseng (PG) and Panax quinquefolius (PQ) on body temperature using these models. In addition, we investigated the effects of PG and PQ in our animal models in high and low temperature environments. The results of our experiments show that mice with normothermia, hyperthermia, and hypothermia maintained their body temperatures after a certain period in accordance with the condition of each animal model. In our experiments of body temperature change in models of normal, low, or high room temperature, the hyperthermic model did not show any body temperature change in either the PG- or PQ-administered group. In the normal and low room temperature models, the group administered PG maintained body temperature, while the body temperature of the PQ-administered group was lower than or similar to that of the control group. In conclusion, the fact that PG increases body temperature could not be verified until now. We also showed that the effect of maintaining body temperature in the PG-administered group was superior in a hypothermia-prone low temperature environment. PMID:25709709

Experimental manipulation of melanism demonstrates the plasticity of preferred temperature in an agricultural pest (Phaulacridium vittatum).

PubMed

Harris, Rebecca M B; McQuillan, Peter; Hughes, Lesley

2013-01-01

Phenotypic plasticity is a key trait of successful pest species, and may increase the ability to cope with higher, more variable temperatures under climate change. We investigate the plasticity of preferred temperature in a widespread agricultural pest, the wingless grasshopper (Phaulacridium vittatum). Preferred temperature is a measure of thermoregulatory behaviour through habitat selection. It is influenced by melanism, which affects body temperature by determining the amount of radiation absorbed by the body. First we demonstrate that body temperature and preferred temperature in P. vittatum is influenced by melanism, by comparing the preferred temperature of the colour morphs in laboratory thermal gradients and field body temperatures in natural populations. We then test whether preferred temperature changes in response to changes in body temperature, by determining preferred temperature before and after manipulation of melanism by painting. When melanism was manipulated experimentally in live grasshoppers, preferred temperature changed to reflect the thermal qualities of the new colour. The preferred temperature of light grasshoppers increased after they were painted black, and decreased after being painted white. Similarly, dark individuals that were painted white behaved like a light individual, maintaining a lower body temperature. Preferred temperature in P.vittatum is a plastic thermoregulatory response to ambient temperature, mediated by the influence of melanism on body temperature.

Experimental Manipulation of Melanism Demonstrates the Plasticity of Preferred Temperature in an Agricultural Pest (Phaulacridium vittatum)

PubMed Central

Harris, Rebecca M. B.; McQuillan, Peter; Hughes, Lesley

2013-01-01

Phenotypic plasticity is a key trait of successful pest species, and may increase the ability to cope with higher, more variable temperatures under climate change. We investigate the plasticity of preferred temperature in a widespread agricultural pest, the wingless grasshopper (Phaulacridium vittatum). Preferred temperature is a measure of thermoregulatory behaviour through habitat selection. It is influenced by melanism, which affects body temperature by determining the amount of radiation absorbed by the body. First we demonstrate that body temperature and preferred temperature in P. vittatum is influenced by melanism, by comparing the preferred temperature of the colour morphs in laboratory thermal gradients and field body temperatures in natural populations. We then test whether preferred temperature changes in response to changes in body temperature, by determining preferred temperature before and after manipulation of melanism by painting. When melanism was manipulated experimentally in live grasshoppers, preferred temperature changed to reflect the thermal qualities of the new colour. The preferred temperature of light grasshoppers increased after they were painted black, and decreased after being painted white. Similarly, dark individuals that were painted white behaved like a light individual, maintaining a lower body temperature. Preferred temperature in P.vittatum is a plastic thermoregulatory response to ambient temperature, mediated by the influence of melanism on body temperature. PMID:24223223

Body temperature stability achieved by the large body mass of sea turtles.

PubMed

Sato, Katsufumi

2014-10-15

To investigate the thermal characteristics of large reptiles living in water, temperature data were continuously recorded from 16 free-ranging loggerhead turtles, Caretta caretta, during internesting periods using data loggers. Core body temperatures were 0.7-1.7°C higher than ambient water temperatures and were kept relatively constant. Unsteady numerical simulations using a spherical thermodynamic model provided mechanistic explanations for these phenomena, and the body temperature responses to fluctuating water temperature can be simply explained by a large body mass with a constant thermal diffusivity and a heat production rate rather than physiological thermoregulation. By contrast, body temperatures increased 2.6-5.1°C in 107-152 min during their emergences to nest on land. The estimated heat production rates on land were 7.4-10.5 times the calculated values in the sea. The theoretical prediction that temperature difference between body and water temperatures would increase according to the body size was confirmed by empirical data recorded from several species of sea turtles. Comparing previously reported data, the internesting intervals of leatherback, green and loggerhead turtles were shorter when the body temperatures were higher. Sea turtles seem to benefit from a passive thermoregulatory strategy, which depends primarily on the physical attributes of their large body masses. © 2014. Published by The Company of Biologists Ltd.

Effect of a Single Musical Cakra Activation Manoeuvre on Body Temperature: An Exploratory Study

PubMed Central

Sumathy, Sundar; Parmar, Parin N

2016-01-01

Cakra activation/balancing and music therapy are part of the traditional Indian healing system. Little is known about effect of musical (vocal) technique of cakra activation on body temperature. We conducted a single-session exploratory study to evaluate effects of a single musical (vocal) cakra activation manoeuvre on body temperature in controlled settings. Seven healthy adults performed a single musical (vocal) cakra activation manoeuvre for approximately 12 minutes in controlled environmental conditions. Pre- and post-manoeuvre body temperatures were recorded with a clinical mercury thermometer. After a single manoeuvre, increase in body temperature was recorded in all seven subjects. The range of increase in body temperature was from 0.2°F to 1.4°F; with mean temperature rise being 0.5°F and median temperature rise being 0.4°F. We conclude that a single session of musical (vocal) technique of cakra activation elevated body temperatures in all 7 subjects. Further research is required to study effects of various cakra activation techniques on body temperature and other physiological parameters. PMID:28182030

Effect of a Single Musical Cakra Activation Manoeuvre on Body Temperature: An Exploratory Study.

PubMed

Sumathy, Sundar; Parmar, Parin N

2016-01-01

Cakra activation/balancing and music therapy are part of the traditional Indian healing system. Little is known about effect of musical (vocal) technique of cakra activation on body temperature. We conducted a single-session exploratory study to evaluate effects of a single musical (vocal) cakra activation manoeuvre on body temperature in controlled settings. Seven healthy adults performed a single musical (vocal) cakra activation manoeuvre for approximately 12 minutes in controlled environmental conditions. Pre- and post-manoeuvre body temperatures were recorded with a clinical mercury thermometer. After a single manoeuvre, increase in body temperature was recorded in all seven subjects. The range of increase in body temperature was from 0.2°F to 1.4°F; with mean temperature rise being 0.5°F and median temperature rise being 0.4°F. We conclude that a single session of musical (vocal) technique of cakra activation elevated body temperatures in all 7 subjects. Further research is required to study effects of various cakra activation techniques on body temperature and other physiological parameters.

Locomotor Activity and Body Temperature Patterns over a Temperature Gradient in the Highveld Mole-Rat (Cryptomys hottentotus pretoriae).

PubMed

Haupt, Meghan; Bennett, Nigel C; Oosthuizen, Maria K

2017-01-01

African mole-rats are strictly subterranean mammals that live in extensive burrow systems. High humidity levels in the burrows prevent mole-rats from thermoregulating using evaporative cooling. However, the relatively stable environment of the burrows promotes moderate temperatures and small daily temperature fluctuations. Mole-rats therefore display a relatively wide range of thermoregulation abilities. Some species cannot maintain their body temperatures at a constant level, whereas others employ behavioural thermoregulation. Here we test the effect of ambient temperature on locomotor activity and body temperature, and the relationship between the two parameters, in the highveld mole-rat. We exposed mole-rats to a 12L:12D and a DD light cycle at ambient temperatures of 30°C, 25°C and 20°C while locomotor activity and body temperature were measured simultaneously. In addition, we investigated the endogenous rhythms of locomotor activity and body temperature at different ambient temperatures. Mole-rats displayed nocturnal activity at all three ambient temperatures and were most active at 20°C, but least active at 30°C. Body temperature was highest at 30°C and lowest at 20°C, and the daily cycle was highly correlated with locomotor activity. We show that the mole-rats have endogenous rhythms for both locomotor activity and body temperature. However, the endogenous body temperature rhythm appears to be less robust compared to the locomotor activity rhythm. Female mole-rats appear to be more sensitive to temperature changes than males, increased heterothermy is evident at lower ambient temperatures, whilst males show smaller variation in their body temperatures with changing ambient temperatures. Mole-rats may rely more heavily on behavioural thermoregulation as it is more energy efficient in an already challenging environment.

Locomotor Activity and Body Temperature Patterns over a Temperature Gradient in the Highveld Mole-Rat (Cryptomys hottentotus pretoriae)

PubMed Central

Haupt, Meghan; Bennett, Nigel C.

2017-01-01

African mole-rats are strictly subterranean mammals that live in extensive burrow systems. High humidity levels in the burrows prevent mole-rats from thermoregulating using evaporative cooling. However, the relatively stable environment of the burrows promotes moderate temperatures and small daily temperature fluctuations. Mole-rats therefore display a relatively wide range of thermoregulation abilities. Some species cannot maintain their body temperatures at a constant level, whereas others employ behavioural thermoregulation. Here we test the effect of ambient temperature on locomotor activity and body temperature, and the relationship between the two parameters, in the highveld mole-rat. We exposed mole-rats to a 12L:12D and a DD light cycle at ambient temperatures of 30°C, 25°C and 20°C while locomotor activity and body temperature were measured simultaneously. In addition, we investigated the endogenous rhythms of locomotor activity and body temperature at different ambient temperatures. Mole-rats displayed nocturnal activity at all three ambient temperatures and were most active at 20°C, but least active at 30°C. Body temperature was highest at 30°C and lowest at 20°C, and the daily cycle was highly correlated with locomotor activity. We show that the mole-rats have endogenous rhythms for both locomotor activity and body temperature. However, the endogenous body temperature rhythm appears to be less robust compared to the locomotor activity rhythm. Female mole-rats appear to be more sensitive to temperature changes than males, increased heterothermy is evident at lower ambient temperatures, whilst males show smaller variation in their body temperatures with changing ambient temperatures. Mole-rats may rely more heavily on behavioural thermoregulation as it is more energy efficient in an already challenging environment. PMID:28072840

Plasticity in body temperature and metabolic capacity sustains winter activity in a small endotherm (Rattus fuscipes).

PubMed

Glanville, Elsa J; Seebacher, Frank

2010-03-01

Small mammals that remain active throughout the year at a constant body temperature have a much greater energy and food requirement in winter. Lower body temperatures in winter may offset the increased energetic cost of remaining active in the cold, if cellular metabolism is not constrained by a negative thermodynamic effect. We aimed to determine whether variable body temperatures can be advantageous for small endotherms by testing the hypothesis that body temperature fluctuates seasonally in a wild rat (Rattus fuscipes); conferring an energy saving and reducing food requirements during resource restricted winter. Additionally we tested whether changes in body temperature affected tissue specific metabolic capacity. Winter acclimatized rats had significantly lower body temperatures and thicker fur than summer acclimatized rats. Mitochondrial oxygen consumption and the activity of enzymes that control oxidative (citrate synthase, cytochrome c-oxidase) and anaerobic (lactate dehydrogenase) metabolism were elevated in winter and were not negatively affected by the lower body temperature. Energy transfer modeling showed that lower body temperatures in winter combined with increased fur thickness to confer a 25 kJ day(-1) energy saving, with up to 50% owing to reduced body temperature alone. We show that phenotypic plasticity at multiple levels of organization is an important component of the response of a small endotherm to winter. Mitochondrial function compensates for lower winter body temperatures, buffering metabolic heat production capacity. Copyright 2009 Elsevier Inc. All rights reserved.

Is there an association between body temperature and serum lactate levels in hip fracture patients?

PubMed

Murtuza, F; Farrier, A J; Venkatesan, M; Smith, R; Khan, A; Uzoigwe, C E; Chami, G

2015-10-01

Introduction Hyperlactataemia is associated with adverse outcomes in trauma cases. It is thought to be the result of anaerobic respiration during hypoperfusion. This produces much less energy than complete aerobic glycolysis. Low body temperature in the injured patient carries an equally poor prognosis. Significant amounts of energy are expended in maintaining euthermia. Consequently, there may be a link between lactate levels and dysthermia. Hyperlactataemia may be indicative of inefficient energy production and therefore insufficient energy to maintain euthermia. Alternatively, significant amounts of available oxygen may be sequestered in thermoregulation, resulting in anaerobic respiration and lactate production. Our study investigated whether there is an association between lactate levels and admission body temperature in hip fracture patients. Furthermore, it looked at whether there is a difference in the mean lactate levels between hip fracture patients with low (<36.5°C), normal (36.5-37.5°C) and high (>37.5°C) body temperature on admission, and for patients who have low body temperature, whether there is a progressive rise in serum lactate levels as body temperature falls. Methods The admission temperature and serum lactate of 1,162 patients presenting with hip fracture were recorded. Patients were divided into the euthermic (body temperature 36.5-37.5°C), the pyrexial (>37.5°C) and those with low body temperature (<36.5°C). Admission lactate and body temperature were compared. Results There was a significant difference in age between the three body temperature groups (p=0.007). The pyrexial cohort was younger than the low body temperature group (mean: 78 vs 82 years). Those with low body temperature had a higher mean lactate level than the euthermic (2.2mmol/l vs 2.0mmol/l, p=0.03). However, there was no progressive rise in serum lactate level as admission temperature fell. Conclusions The findings suggest that in hip fracture patients, the body attempts initially to maintain euthermia, incurring an oxygen debt. This would explain the difference in lactate level between the low body temperature and euthermic cohorts. The fact that there is no correlation with the degree of temperature depression and lactate levels indicates that the body does not fuel thermohomeostasis indefinitely with oxygen. Instead, in part, it abandons thermoregulatory mechanisms. Consequently, in this population, active rewarming may be indicated rather than depending on patients' own thermogenic ability.

Variation in the sensitivity of organismal body temperature to climate change over local and geographic scales.

PubMed

Gilman, Sarah E; Wethey, David S; Helmuth, Brian

2006-06-20

Global climate change is expected to have broad ecological consequences for species and communities. Attempts to forecast these consequences usually assume that changes in air or water temperature will translate into equivalent changes in a species' organismal body temperature. This simple change is unlikely because an organism's body temperature is determined by a complex series of interactions between the organism and its environment. Using a biophysical model, validated with 5 years of field observations, we examined the relationship between environmental temperature change and body temperature of the intertidal mussel Mytilus californianus over 1,600 km of its geographic distribution. We found that at all locations examined simulated changes in air or water temperature always produced less than equivalent changes in the daily maximum mussel body temperature. Moreover, the magnitude of body temperature change was highly variable, both within and among locations. A simulated 1 degrees C increase in air or water temperature raised the maximum monthly average of daily body temperature maxima by 0.07-0.92 degrees C, depending on the geographic location, vertical position, and temperature variable. We combined these sensitivities with predicted climate change for 2100 and calculated increases in monthly average maximum body temperature of 0.97-4.12 degrees C, depending on location and climate change scenario. Thus geographic variation in body temperature sensitivity can modulate species' experiences of climate change and must be considered when predicting the biological consequences of climate change.

Relationship between body temperature, weight, and hematological parameters of black tufted-ear marmosets (Callithrix penicillata).

PubMed

Pereira, Lucas Cardoso; Barros, Marilia

2016-06-01

Basal thermal values of captive adult black tufted-ear marmosets (Callithrix penicillata) in a thermoneutral environment were measured via different methods, along with body weight and hematological parameters. Body temperatures were recorded with rectal (RC), subcutaneous (SC) microchip transponder and infrared (left and right) tympanic membrane (TM) thermometries. Thermal values were correlated with body mass and some hematological data. Similar RC and SC temperatures were observed, these being significantly higher than the left and right TM values. SC temperature was positively correlated and in close agreement with RC measurements. Although body temperatures were not influenced by gender, capture time, or body weight, they were correlated with hematological parameters. Thus, body temperatures in this species seem to reflect some of the characteristics of the assessments' location, with SC microchip transponders being a less invasive method to assess body temperature in these small-bodied non-human primates. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

A cross-species translational pharmacokinetic-pharmacodynamic evaluation of core body temperature reduction by the TRPM8 blocker PF-05105679.

PubMed

Gosset, James R; Beaumont, Kevin; Matsuura, Tomomi; Winchester, Wendy; Attkins, Neil; Glatt, Sophie; Lightbown, Ian; Ulrich, Kristina; Roberts, Sonia; Harris, Jolie; Mesic, Emir; van Steeg, Tamara; Hijdra, Diana; van der Graaf, Piet H

2017-11-15

PF-05105679 is a moderately potent TRPM8 blocker which has been evaluated for the treatment of cold pain sensitivity. The TRPM8 channel is responsible for the sensation of cold environmental temperatures and has been implicated in regulation of core body temperature. Consequently, blockade of TRPM8 has been suggested to result in lowering of core body temperature. As part of the progression to human studies, the effect of PF-05105679 on core body temperature has been investigated in animals. Safety pharmacology studies showed that PF-05105679 reduced core body temperature in a manner that was inversely related to body weight of the species tested (greater exposure to PF-05105679 was required to lower temperature by 1°C in higher species). Based on an allometric (body weight) relationship, it was hypothesized that PF-05105679 would not lower core body temperature in humans at exposures that could exhibit pharmacological effects on cold pain sensation. On administration to humans, PF-05105679 was indeed effective at reversing the cold pain sensation associated with the cold pressor test in the absence of effects on core body temperature. Copyright © 2017 Elsevier B.V. All rights reserved.

Regulation of body temperature and brown adipose tissue thermogenesis by bombesin receptor subtype-3

PubMed Central

Lateef, Dalya M.; Abreu-Vieira, Gustavo; Xiao, Cuiying

2014-01-01

Bombesin receptor subtype-3 (BRS-3) regulates energy homeostasis, with Brs3 knockout (Brs3−/y) mice being hypometabolic, hypothermic, and hyperphagic and developing obesity. We now report that the reduced body temperature is more readily detected if body temperature is analyzed as a function of physical activity level and light/dark phase. Physical activity level correlated best with body temperature 4 min later. The Brs3−/y metabolic phenotype is not due to intrinsically impaired brown adipose tissue function or in the communication of sympathetic signals from the brain to brown adipose tissue, since Brs3−/y mice have intact thermogenic responses to stress, acute cold exposure, and β3-adrenergic activation, and Brs3−/y mice prefer a cooler environment. Treatment with the BRS-3 agonist MK-5046 increased brown adipose tissue temperature and body temperature in wild-type but not Brs3−/y mice. Intrahypothalamic infusion of MK-5046 increased body temperature. These data indicate that the BRS-3 regulation of body temperature is via a central mechanism, upstream of sympathetic efferents. The reduced body temperature in Brs3−/y mice is due to altered regulation of energy homeostasis affecting higher center regulation of body temperature, rather than an intrinsic defect in brown adipose tissue. PMID:24452453

[Thermal tolerance, diel variation of body temperature, and thermal dependence of locomotor performance of hatchling soft-shelled turtles, Trionyx sinensis].

PubMed

Sun, Pingyue; Xu, Xiaoyin; Chen, Huili; Ji, Xiang

2002-09-01

The thermal tolerance, body temperature, and influence of temperature on locomotor performance of hatchling soft-shelled turtles (Trionyx sinensis) were studied under dry and wet conditions, and the selected body temperature of hatchlings was 28.0 and 30.3 degrees C, respectively. Under wet condition, the critical thermal maximum and minimum averaged 40.9 and 7.8 degrees C, respectively. In the environments without thermal gradients, the diel variation of body temperature was highly consistent with the variation of both air and water temperatures, and the body temperature was more directly affected by water temperature than by air temperature, which implied that the physiological thermoregulation of hatchling T. sinensis was very weak. In the environments with thermal gradients, hatchling turtles could maintain relatively high and constant body temperatures, primarily through behavioral thermoregulation. The locomotor performance of hatchling turtles was highly dependent on their body temperature. Within a certain range, the locomotor performance increased with increasing body temperature. In our study, the optimal body temperature for locomotor performance was 31.5 degrees C, under which, the maximum continuous running distance, running distance per minute, and number of stops per minute averaged 1.87 m, 4.92 m.min-1, and 6.2 times.min-1, respectively. The correspondent values at 33.0 degrees C averaged 1.30 m, 4.28 m.min-1, and 7.7 times.min-1, respectively, which indicated that the locomotor performance of hatchling turtles was impaired at 33.0 degrees C. Therefore, extremely high body temperatures might have an adverse effect on locomotor performance of hatchling turtles.

Body temperature changes during simulated bacterial infection in a songbird: fever at night and hypothermia during the day.

PubMed

Sköld-Chiriac, Sandra; Nord, Andreas; Tobler, Michael; Nilsson, Jan-Åke; Hasselquist, Dennis

2015-09-01

Although fever (a closely regulated increase in body temperature in response to infection) typically is beneficial, it is energetically costly and may induce detrimentally high body temperatures. This can increase the susceptibility to energetic bottlenecks and risks of overheating in some organisms. Accordingly, it could be particularly interesting to study fever in small birds, which have comparatively high metabolic rates and high, variable body temperatures. We therefore investigated two aspects of fever and other sickness behaviours (circadian variation, dose dependence) in a small songbird, the zebra finch. We injected lipopolysaccharide (LPS) at the beginning of either the day or the night, and subsequently monitored body temperature, body mass change and food intake for the duration of the response. We found pronounced circadian variation in the body temperature response to LPS injection, manifested by (dose-dependent) hypothermia during the day but fever at night. This resulted in body temperature during the peak response being relatively similar during the day and night. Day-to-night differences might be explained in the context of circadian variation in body temperature: songbirds have a high daytime body temperature that is augmented by substantial heat production peaks during activity. This might require a trade-off between the benefit of fever and the risk of overheating. In contrast, at night, when body temperature is typically lower and less variable, fever can be used to mitigate infection. We suggest that the change in body temperature during infection in small songbirds is context dependent and regulated to promote survival according to individual demands at the time of infection. © 2015. Published by The Company of Biologists Ltd.

Turtles (Chelodina longicollis) regulate muscle metabolic enzyme activity in response to seasonal variation in body temperature.

PubMed

Seebacher, F; Sparrow, J; Thompson, M B

2004-04-01

Fluctuations in the thermal environment may elicit different responses in animals: migration to climatically different areas, regulation of body temperature, modification of biochemical reaction rates, or assuming a state of dormancy. Many ectothermic reptiles are active over a range of body temperatures that vary seasonally. Here we test the hypothesis that metabolic enzyme activity acclimatises seasonally in freshwater turtles (Chelodina longicollis) in addition to, or instead of, behavioural regulation of body temperatures. We measured body temperatures in free-ranging turtles (n = 3) by radiotelemetry, and we assayed phosphofructokinase (PFK), lactate dehydrogenase (LDH), citrate synthase (CS) and cytochrome c oxidase (CCO) activities in early autumn (March, n = 10 turtles), late autumn (May, n = 7) and mid-winter (July, n = 7) over a range of assay temperatures (10 degrees C, 15 degrees C, 20 degrees C, 25 degrees C). Body temperatures were either not different from, or higher than expected from a theoretical null-distribution of a randomly moving animal. Field body temperatures at any season were lower, however, than expected from animals that maximised their sun exposure. Turtles maintained constant PFK, LDH and CCO activities in different months, despite body temperature differences of nearly 13.0 degrees C between March (average daily body temperature = 24.4 degrees C) and July (average = 11.4 degrees C). CS activity did not vary between March and May (average daily body temperature = 20.2 degrees C), but it decreased in July. Thus C. longicollis use a combination of behavioural thermoregulation and biochemical acclimatisation in response to seasonally changing thermal conditions. Ectothermic reptiles were often thought not to acclimatise biochemically, and our results show that behavioural attainment of a preferred body temperature is not mandatory for activity or physiological performance in turtles. Copyright 2004 Springer-Verlag

A Random Walk in the Park: An Individual-Based Null Model for Behavioral Thermoregulation.

PubMed

Vickers, Mathew; Schwarzkopf, Lin

2016-04-01

Behavioral thermoregulators leverage environmental temperature to control their body temperature. Habitat thermal quality therefore dictates the difficulty and necessity of precise thermoregulation, and the quality of behavioral thermoregulation in turn impacts organism fitness via the thermal dependence of performance. Comparing the body temperature of a thermoregulator with a null (non-thermoregulating) model allows us to estimate habitat thermal quality and the effect of behavioral thermoregulation on body temperature. We define a null model for behavioral thermoregulation that is a random walk in a temporally and spatially explicit thermal landscape. Predicted body temperature is also integrated through time, so recent body temperature history, environmental temperature, and movement influence current body temperature; there is no particular reliance on an organism's equilibrium temperature. We develop a metric called thermal benefit that equates body temperature to thermally dependent performance as a proxy for fitness. We measure thermal quality of two distinct tropical habitats as a temporally dynamic distribution that is an ergodic property of many random walks, and we compare it with the thermal benefit of real lizards in both habitats. Our simple model focuses on transient body temperature; as such, using it we observe such subtleties as shifts in the thermoregulatory effort and investment of lizards throughout the day, from thermoregulators to thermoconformers.

Is there an association between body temperature and serum lactate levels in hip fracture patients?

PubMed Central

Murtuza, F; Farrier, AJ; Venkatesan, M; Smith, R; Khan, A; Uzoigwe, CE; Chami, G

2015-01-01

Introduction Hyperlactataemia is associated with adverse outcomes in trauma cases. It is thought to be the result of anaerobic respiration during hypoperfusion. This produces much less energy than complete aerobic glycolysis. Low body temperature in the injured patient carries an equally poor prognosis. Significant amounts of energy are expended in maintaining euthermia. Consequently, there may be a link between lactate levels and dysthermia. Hyperlactataemia may be indicative of inefficient energy production and therefore insufficient energy to maintain euthermia. Alternatively, significant amounts of available oxygen may be sequestered in thermoregulation, resulting in anaerobic respiration and lactate production. Our study investigated whether there is an association between lactate levels and admission body temperature in hip fracture patients. Furthermore, it looked at whether there is a difference in the mean lactate levels between hip fracture patients with low (<36.5°C), normal (36.5–37.5°C) and high (>37.5°C) body temperature on admission, and for patients who have low body temperature, whether there is a progressive rise in serum lactate levels as body temperature falls. Methods The admission temperature and serum lactate of 1,162 patients presenting with hip fracture were recorded. Patients were divided into the euthermic (body temperature 36.5–37.5°C), the pyrexial (>37.5°C) and those with low body temperature (<36.5°C). Admission lactate and body temperature were compared. Results There was a significant difference in age between the three body temperature groups (p=0.007). The pyrexial cohort was younger than the low body temperature group (mean: 78 vs 82 years). Those with low body temperature had a higher mean lactate level than the euthermic (2.2mmol/l vs 2.0mmol/l, p=0.03). However, there was no progressive rise in serum lactate level as admission temperature fell. Conclusions The findings suggest that in hip fracture patients, the body attempts initially to maintain euthermia, incurring an oxygen debt. This would explain the difference in lactate level between the low body temperature and euthermic cohorts. The fact that there is no correlation with the degree of temperature depression and lactate levels indicates that the body does not fuel thermohomeostasis indefinitely with oxygen. Instead, in part, it abandons thermoregulatory mechanisms. Consequently, in this population, active rewarming may be indicated rather than depending on patients’ own thermogenic ability. PMID:26274739

Variation in the daily rhythm of body temperature of free-living Arabian oryx (Oryx leucoryx): does water limitation drive heterothermy?

PubMed

Hetem, Robyn Sheila; Strauss, Willem Maartin; Fick, Linda Gayle; Maloney, Shane Kevin; Meyer, Leith Carl Rodney; Shobrak, Mohammed; Fuller, Andrea; Mitchell, Duncan

2010-10-01

Heterothermy, a variability in body temperature beyond the limits of homeothermy, has been advanced as a key adaptation of Arabian oryx (Oryx leucoryx) to their arid-zone life. We measured body temperature using implanted data loggers, for a 1-year period, in five oryx free-living in the deserts of Saudi Arabia. As predicted for adaptive heterothermy, during hot months compared to cooler months, not only were maximum daily body temperatures higher (41.1 ± 0.3 vs. 39.7 ± 0.1°C, P = 0.0002) but minimum daily body temperatures also were lower (36.1 ± 0.3 vs. 36.8 ± 0.2°C, P = 0.04), resulting in a larger daily amplitude of the body temperature rhythm (5.0 ± 0.5 vs. 2.9 ± 0.2°C, P = 0.0007), while mean daily body temperature rose by only 0.4°C. The maximum daily amplitude of the body temperature rhythm reached 7.7°C for two of our oryx during the hot-dry period, the largest amplitude ever recorded for a large mammal. Body temperature variability was influenced not only by ambient temperature but also water availability, with oryx displaying larger daily amplitudes of the body temperature rhythm during warm-dry months compared to warm-wet months (3.6 ± 0.6 vs. 2.3 ± 0.3°C, P = 0.005), even though ambient temperatures were the same. Free-living Arabian oryx therefore employ heterothermy greater than that recorded in any other large mammal, but water limitation, rather than high ambient temperature, seems to be the primary driver of this heterothermy.

Non-invasive, transient determination of the core temperature of a heat-generating solid body

PubMed Central

Anthony, Dean; Sarkar, Daipayan; Jain, Ankur

2016-01-01

While temperature on the surface of a heat-generating solid body can be easily measured using a variety of methods, very few techniques exist for non-invasively measuring the temperature inside the solid body as a function of time. Measurement of internal temperature is very desirable since measurement of just the surface temperature gives no indication of temperature inside the body, and system performance and safety is governed primarily by the highest temperature, encountered usually at the core of the body. This paper presents a technique to non-invasively determine the internal temperature based on the theoretical relationship between the core temperature and surface temperature distribution on the outside of a heat-generating solid body as functions of time. Experiments using infrared thermography of the outside surface of a thermal test cell in a variety of heating and cooling conditions demonstrate good agreement of the predicted core temperature as a function of time with actual core temperature measurement using an embedded thermocouple. This paper demonstrates a capability to thermally probe inside solid bodies in a non-invasive fashion. This directly benefits the accurate performance prediction and control of a variety of engineering systems where the time-varying core temperature plays a key role. PMID:27804981

Non-invasive, transient determination of the core temperature of a heat-generating solid body

NASA Astrophysics Data System (ADS)

Anthony, Dean; Sarkar, Daipayan; Jain, Ankur

2016-11-01

While temperature on the surface of a heat-generating solid body can be easily measured using a variety of methods, very few techniques exist for non-invasively measuring the temperature inside the solid body as a function of time. Measurement of internal temperature is very desirable since measurement of just the surface temperature gives no indication of temperature inside the body, and system performance and safety is governed primarily by the highest temperature, encountered usually at the core of the body. This paper presents a technique to non-invasively determine the internal temperature based on the theoretical relationship between the core temperature and surface temperature distribution on the outside of a heat-generating solid body as functions of time. Experiments using infrared thermography of the outside surface of a thermal test cell in a variety of heating and cooling conditions demonstrate good agreement of the predicted core temperature as a function of time with actual core temperature measurement using an embedded thermocouple. This paper demonstrates a capability to thermally probe inside solid bodies in a non-invasive fashion. This directly benefits the accurate performance prediction and control of a variety of engineering systems where the time-varying core temperature plays a key role.

Temperature alters food web body-size structure.

PubMed

Gibert, Jean P; DeLong, John P

2014-08-01

The increased temperature associated with climate change may have important effects on body size and predator-prey interactions. The consequences of these effects for food web structure are unclear because the relationships between temperature and aspects of food web structure such as predator-prey body-size relationships are unknown. Here, we use the largest reported dataset for marine predator-prey interactions to assess how temperature affects predator-prey body-size relationships among different habitats ranging from the tropics to the poles. We found that prey size selection depends on predator body size, temperature and the interaction between the two. Our results indicate that (i) predator-prey body-size ratios decrease with predator size at below-average temperatures and increase with predator size at above-average temperatures, and (ii) that the effect of temperature on predator-prey body-size structure will be stronger at small and large body sizes and relatively weak at intermediate sizes. This systematic interaction may help to simplify forecasting the potentially complex consequences of warming on interaction strengths and food web stability. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Morphological and ecological determinants of body temperature of Geukensia demissa, the Atlantic ribbed mussel, and their effects on mussel mortality.

PubMed

Jost, Jennifer; Helmuth, Brian

2007-10-01

Measurements of body temperatures in the field have shown that spatial and temporal patterns are often far more complex than previously anticipated, particularly in intertidal regions, where temperatures are driven by both marine and terrestrial climates. We examined the effects of body size, body position within the sediment, and microhabitat (presence or absence of Spartina alterniflora) on the body temperature of the mussel Geukensia demissa. We then used these data to develop a laboratory study exposing mussels to an artificial "stressful" day, mimicking field conditions as closely as possible. Results suggested that G. demissa mortality increases greatly at average daily peak temperatures of 45 degrees C and higher. When these temperatures were compared to field data collected in South Carolina in the summer of 2004, our data indicated that mussels likely experienced mortality due to high-temperature stress at this site during this period. Our results also showed that body position in the mud is the most important environmental modifier of body temperature. This experiment suggested that the presence of marsh grass leads to increases in body temperature by reducing convection, overwhelming the effects of shading. These data add to a growing body of evidence showing that small-scale thermal variability can surpass large-scale gradients.

Estimation of body temperature rhythm based on heart activity parameters in daily life.

PubMed

Sooyoung Sim; Heenam Yoon; Hosuk Ryou; Kwangsuk Park

2014-01-01

Body temperature contains valuable health related information such as circadian rhythm and menstruation cycle. Also, it was discovered from previous studies that body temperature rhythm in daily life is related with sleep disorders and cognitive performances. However, monitoring body temperature with existing devices during daily life is not easy because they are invasive, intrusive, or expensive. Therefore, the technology which can accurately and nonintrusively monitor body temperature is required. In this study, we developed body temperature estimation model based on heart rate and heart rate variability parameters. Although this work was inspired by previous research, we originally identified that the model can be applied to body temperature monitoring in daily life. Also, we could find out that normalized Mean heart rate (nMHR) and frequency domain parameters of heart rate variability showed better performance than other parameters. Although we should validate the model with more number of subjects and consider additional algorithms to decrease the accumulated estimation error, we could verify the usefulness of this approach. Through this study, we expect that we would be able to monitor core body temperature and circadian rhythm from simple heart rate monitor. Then, we can obtain various health related information derived from daily body temperature rhythm.

Basal body temperature method for detecting ovarian cycle in the Captive Beluga (Delphinapterus leucas).

PubMed

Katsumata, Etsuko; Furuta, Chie; Katsumata, Hiroshi; Watanabe, Gen; Taya, Kazuyoshi

2006-02-01

The relationship between basal body temperature and circulating progesterone levels were investigated in a female beluga. Body temperature and serum concentrations of progesterone were measured daily and at 2-4 week intervals respectively, in a female beluga that was in captivity for 7 years between 1996 and 2003. The beluga first ovulated in April, 2000 (13 years old). Thereafter, serum concentrations of progesterone showed cyclic changes, indicating that the ovulatory cycle had started. Serum concentrations of progesterone ranged from 0.1 ng/ml to 15.7 ng/ml. Body temperature also showed cyclic changes during the estrous cycle. Body temperature ranged from 34.9 to 35.9 C, and tended to reach the peak during the high progesterone phase. Mating behavior was observed during the low body temperature phase. The changes in body temperature positively correlated with the circulating progesterone levels. The length of the estrous cycle was 36.7 +/- 3.9 (mean +/- SEM) days based on the intervals between the days of mating behavior. This is the first report demonstrating that body temperature clearly changes during the estrous cycle in a captive female beluga. The present finding suggests that measurement of body temperature is a useful method for detecting the ovarian cycle of the beluga in captivity.

Comparison of environmental and body temperatures as predictors of mating call parameters of spring peepers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, L.E.; Brown, J.R.

1977-01-01

Parameters of the mating call of spring peepers (Hyla crucifer) were best predicted by water temperature rather than air or body temperature. Thus, water temperature should most closely approach the true body temperature of the calling frogs.

Microchip transponder thermometry for monitoring core body temperature of antelope during capture.

PubMed

Rey, Benjamin; Fuller, Andrea; Hetem, Robyn S; Lease, Hilary M; Mitchell, Duncan; Meyer, Leith C R

2016-01-01

Hyperthermia is described as the major cause of morbidity and mortality associated with capture, immobilization and restraint of wild animals. Therefore, accurately determining the core body temperature of wild animals during capture is crucial for monitoring hyperthermia and the efficacy of cooling procedures. We investigated if microchip thermometry can accurately reflect core body temperature changes during capture and cooling interventions in the springbok (Antidorcas marsupialis), a medium-sized antelope. Subcutaneous temperature measured with a temperature-sensitive microchip was a weak predictor of core body temperature measured by temperature-sensitive data loggers in the abdominal cavity (R(2)=0.32, bias >2 °C). Temperature-sensitive microchips in the gluteus muscle, however, provided an accurate estimate of core body temperature (R(2)=0.76, bias=0.012 °C). Microchips inserted into muscle therefore provide a convenient and accurate method to measure body temperature continuously in captured antelope, allowing detection of hyperthermia and the efficacy of cooling procedures. Copyright © 2015 Elsevier Ltd. All rights reserved.

Regional and circadian variations of sweating rate and body surface temperature in camels (Camelus dromedarius).

PubMed

Abdoun, Khalid A; Samara, Emad M; Okab, Aly B; Al-Haidary, Ahmed A

2012-07-01

It was the aim of this study to investigate the regional variations in surface temperature and sweating rate and to visualize body thermal windows responsible for the dissipation of excess body heat in dromedary camels. This study was conducted on five dromedary camels with mean body weight of 450 ± 20.5 kg and 2 years of age. Sweating rate, skin and body surface temperature showed significant (P < 0.001) circadian variation together with the variation in ambient temperature. However, daily mean values of sweating rate, skin and body surface temperature measured on seven regions of the camel body did not significantly differ. The variation in body surface temperature compared to the variation in skin temperature was higher in the hump compared to the axillary and flank regions, indicating the significance of camel's fur in protecting the skin from daily variation in ambient temperature. Infrared thermography revealed that flank and axillary regions had lower thermal gradients at higher ambient temperature (T(a) ) and higher thermal gradients at lower T(a) , which might indicate the working of flank and axillary regions as thermal windows dissipating heat during the night. Sweating rate showed moderate correlation to skin and body surface temperatures, which might indicate their working as potential thermal drivers of sweating in camels. © 2012 The Authors. Animal Science Journal © 2012 Japanese Society of Animal Science.

Body temperature null distributions in reptiles with nonzero heat capacity: seasonal thermoregulation in the American alligator (Alligator mississippiensis).

PubMed

Seebacher, Frank; Elsey, Ruth M; Trosclair, Phillip L

2003-01-01

Regulation of body temperature may increase fitness of animals by ensuring that biochemical and physiological processes proceed at an optimal rate. The validity of current methods of testing whether or not thermoregulation in reptiles occurs is often limited to very small species that have near zero heat capacity. The aim of this study was to develop a method that allows estimation of body temperature null distributions of large reptiles and to investigate seasonal thermoregulation in the American alligator (Alligator mississippiensis). Continuous body temperature records of wild alligators were obtained from implanted dataloggers in winter (n=7, mass range: 1.6-53.6 kg) and summer (n=7, mass range: 1.9-54.5 kg). Body temperature null distributions were calculated by randomising behavioural postures, thereby randomly altering relative animal surface areas exposed to different avenues of heat transfer. Core body temperatures were predicted by calculations of transient heat transfer by conduction and blood flow. Alligator body temperatures follow regular oscillations during the day. Occasionally, body temperature steadied during the day to fall within a relatively narrow range. Rather than indicating shuttling thermoregulation, however, this pattern could be predicted from random movements. Average daily body temperature increases with body mass in winter but not in summer. Daily amplitudes of body temperature decrease with increasing body mass in summer but not in winter. These patterns result from differential exposure to heat transfer mechanisms at different seasons. In summer, alligators are significantly cooler than predictions for a randomly moving animal, and the reverse is the case in winter. Theoretical predictions show, however, that alligators can be warmer in winter if they maximised their sun exposure. We concluded that alligators may not rely exclusively on regulation of body temperature but that they may also acclimatise biochemically to seasonally changing environmental conditions.

Voluntary Running Aids to Maintain High Body Temperature in Rats Bred for High Aerobic Capacity

PubMed Central

Karvinen, Sira M.; Silvennoinen, Mika; Ma, Hongqiang; Törmäkangas, Timo; Rantalainen, Timo; Rinnankoski-Tuikka, Rita; Lensu, Sanna; Koch, Lauren G.; Britton, Steven L.; Kainulainen, Heikki

2016-01-01

The production of heat, i.e., thermogenesis, is a significant component of the metabolic rate, which in turn affects weight gain and health. Thermogenesis is linked to physical activity (PA) level. However, it is not known whether intrinsic exercise capacity, aging, and long-term voluntary running affect core body temperature. Here we use rat models selectively bred to differ in maximal treadmill endurance running capacity (Low capacity runners, LCR and High capacity Runners, HCR), that as adults are divergent for aerobic exercise capacity, aging, and metabolic disease risk to study the connection between PA and body temperature. Ten high capacity runner (HCR) and ten low capacity runner (LCR) female rats were studied between 9 and 21 months of age. Rectal body temperature of HCR and LCR rats was measured before and after 1-year voluntary running/control intervention to explore the effects of aging and PA. Also, we determined whether injected glucose and spontaneous activity affect the body temperature differently between LCR and HCR rats at 9 vs. 21 months of age. HCRs had on average 1.3°C higher body temperature than LCRs (p < 0.001). Aging decreased the body temperature level of HCRs to similar levels with LCRs. The opportunity to run voluntarily had a significant impact on the body temperature of HCRs (p < 0.001) allowing them to maintain body temperature at a similar level as when at younger age. Compared to LCRs, HCRs were spontaneously more active, had higher relative gastrocnemius muscle mass and higher UCP2, PGC-1α, cyt c, and OXPHOS levels in the skeletal muscle (p < 0.050). These results suggest that higher PA level together with greater relative muscle mass and higher mitochondrial content/function contribute to the accumulation of heat in the HCRs. Interestingly, neither aging nor voluntary training had a significant impact on core body temperature of LCRs. However, glucose injection resulted in a lowering of the body temperature of LCRs (p < 0.050), but not that of HCRs. In conclusion, rats born with high intrinsic capacity for aerobic exercise and better health have higher body temperature compared to rats born with low exercise capacity and disease risk. Voluntary running allowed HCRs to maintain high body temperature during aging, which suggests that high PA level was crucial in maintaining the high body temperature of HCRs. PMID:27504097

Voluntary Running Aids to Maintain High Body Temperature in Rats Bred for High Aerobic Capacity.

PubMed

Karvinen, Sira M; Silvennoinen, Mika; Ma, Hongqiang; Törmäkangas, Timo; Rantalainen, Timo; Rinnankoski-Tuikka, Rita; Lensu, Sanna; Koch, Lauren G; Britton, Steven L; Kainulainen, Heikki

2016-01-01

The production of heat, i.e., thermogenesis, is a significant component of the metabolic rate, which in turn affects weight gain and health. Thermogenesis is linked to physical activity (PA) level. However, it is not known whether intrinsic exercise capacity, aging, and long-term voluntary running affect core body temperature. Here we use rat models selectively bred to differ in maximal treadmill endurance running capacity (Low capacity runners, LCR and High capacity Runners, HCR), that as adults are divergent for aerobic exercise capacity, aging, and metabolic disease risk to study the connection between PA and body temperature. Ten high capacity runner (HCR) and ten low capacity runner (LCR) female rats were studied between 9 and 21 months of age. Rectal body temperature of HCR and LCR rats was measured before and after 1-year voluntary running/control intervention to explore the effects of aging and PA. Also, we determined whether injected glucose and spontaneous activity affect the body temperature differently between LCR and HCR rats at 9 vs. 21 months of age. HCRs had on average 1.3°C higher body temperature than LCRs (p < 0.001). Aging decreased the body temperature level of HCRs to similar levels with LCRs. The opportunity to run voluntarily had a significant impact on the body temperature of HCRs (p < 0.001) allowing them to maintain body temperature at a similar level as when at younger age. Compared to LCRs, HCRs were spontaneously more active, had higher relative gastrocnemius muscle mass and higher UCP2, PGC-1α, cyt c, and OXPHOS levels in the skeletal muscle (p < 0.050). These results suggest that higher PA level together with greater relative muscle mass and higher mitochondrial content/function contribute to the accumulation of heat in the HCRs. Interestingly, neither aging nor voluntary training had a significant impact on core body temperature of LCRs. However, glucose injection resulted in a lowering of the body temperature of LCRs (p < 0.050), but not that of HCRs. In conclusion, rats born with high intrinsic capacity for aerobic exercise and better health have higher body temperature compared to rats born with low exercise capacity and disease risk. Voluntary running allowed HCRs to maintain high body temperature during aging, which suggests that high PA level was crucial in maintaining the high body temperature of HCRs.

Comparison between auricular and standard rectal thermometers for the measurement of body temperature in dogs

PubMed Central

Sousa, Marlos G.; Carareto, Roberta; Pereira-Junior, Valdo A.; Aquino, Monally C.C.

2011-01-01

Although the rectal mucosa remains the traditional site for measuring body temperature in dogs, an increasing number of clinicians have been using auricular temperature to estimate core body temperature. In this study, 88 mature healthy dogs had body temperatures measured with auricular and rectal thermometers. The mean temperature and confidence intervals were similar for each method, but Bland-Altman plots showed high biases and limits of agreement unacceptable for clinical purposes. The results indicate that auricular and rectal temperatures should not be interpreted interchangeably. PMID:21731094

Comparison between auricular and standard rectal thermometers for the measurement of body temperature in dogs.

PubMed

Sousa, Marlos G; Carareto, Roberta; Pereira-Junior, Valdo A; Aquino, Monally C C

2011-04-01

Although the rectal mucosa remains the traditional site for measuring body temperature in dogs, an increasing number of clinicians have been using auricular temperature to estimate core body temperature. In this study, 88 mature healthy dogs had body temperatures measured with auricular and rectal thermometers. The mean temperature and confidence intervals were similar for each method, but Bland-Altman plots showed high biases and limits of agreement unacceptable for clinical purposes. The results indicate that auricular and rectal temperatures should not be interpreted interchangeably.

Seasonal patterns of body temperature and microhabitat selection in a lacertid lizard

NASA Astrophysics Data System (ADS)

Ortega, Zaida; Pérez-Mellado, Valentín

2016-11-01

In temperate areas, seasonal changes entail a source of environmental variation potentially important for organisms. Temperate ectotherms may be adapted to the seasonal fluctuations in environmental traits. For lizards, behavioural adaptations regarding microhabitat selection could arise to improve thermoregulation during the different seasons. However, little is still known about which traits influence microhabitat selection of lizards and their adaptation to seasonality. Here we used Podarcis guadarramae to study the role of potential intrinsic (body size, sex, age) and environmental traits (air and substrate temperatures, wind speed, and sunlight) in the seasonal changes of body temperatures and microhabitat selection of lizards. We measured body temperatures of lizards in the same habitat during the four seasons and compared the climatic variables of the microhabitats selected by lizards with the mean climatic conditions available in their habitat. Body temperatures were similar for adult males, adult females, and juveniles within each season, being significantly higher in summer than in the other seasons, and in spring than in winter. The same pattern was found regarding substrate and air temperatures of the selected microhabitats. Wind speed and air temperature did not affect body temperatures, while body length was marginally significant and substrate temperatures and season did affect the body temperatures of lizards. Our results during the whole year support the idea that the seasonality could be the most important factor affecting body temperatures of these temperate species. Regarding microhabitat selection, environmental constraints, as environmental temperatures and wind speed, affected the seasonal changes on behavioural thermoregulation of lizards. This effect was similar between sexes and age classes, and was independent of body size. In addition, importance of sunlight exposure of the selected microhabitats (full sun, filtered sun, or shade) also changed between seasons. Hence, environmental constraints were the main forces driving seasonal changes in microhabitat selection.

The relationship of normal body temperature, end-expired breath temperature, and BAC/BrAC ratio in 98 physically fit human test subjects.

PubMed

Cowan, J Mack; Burris, James M; Hughes, James R; Cunningham, Margaret P

2010-06-01

The relationship between normal body temperature, end-expired breath temperature, and blood alcohol concentration (BAC)/breath alcohol concentration (BrAC) ratio was studied in 98 subjects (84 men, 14 women). Subjects consumed alcohol sufficient to produce a BrAC of at least 0.06 g/210 L 45-75 min after drinking. Breath samples were analyzed using an Intoxilyzer 8000 specially equipped to measure breath temperature. Venous blood samples and body temperatures were then taken. The mean body temperature of the men (36.6 degrees C) was lower than the women (37.0 degrees C); however, their mean breath temperatures were virtually identical (men: 34.5 degrees C; women: 34.6 degrees C). The BAC exceeded the BrAC for every subject. BAC/BrAC ratios were calculated from the BAC and BrAC analytical results. There was no difference in the BAC/BrAC ratios for men (1:2379) and women (1:2385). The correlation between BAC and BrAC was high (r = 0.938, p < 0.0001), whereas the correlations between body temperature and end-expired breath temperature, body temperature and BAC/BrAC ratio, and breath temperature and BAC/BrAC ratio were much lower. Neither normal body temperature nor end-expired breath temperature was strongly associated with BAC/BrAC ratio.

Does the body temperature change in older people?

PubMed

Güneş, Ulkü Yapucu; Zaybak, Ayten

2008-09-01

The aim of this study was to determine the mean body temperatures in older people using mercury-in-glass thermometer. Older people are unable to regulate their body temperatures to the same degree as young adults because their responses to changes in body temperature are altered. Several published reports suggest that body temperature decreases with advancing age and has a greater variability in older populations. The aim of this study was to determine the mean body temperatures in older people. Non-experimental. Axillary body temperatures were taken in 133 older subjects in a nursing home for older people using mercury-in-glass thermometer. Temperatures were measured at 8 a.m., 2 p.m., and 6 p.m., over three consecutive days. Each subject had all three measurements taken on the same day. The mean age of the subjects was 77.2, SD 7.3. In the 133 older subjects, the mean axillary temperatures ranged from 35.1 to 36.4 degrees C (95.3-97.6 degrees F). The mean temperatures for those aged 65-74 was higher than in those aged 75-84 (p < 0.001) and those aged 85 and older (p < 0.001) at 6 p.m. but not at 8 a.m. or 2 p.m. We concluded that older people have mean axillary body temperatures lower than the reference point of 36.5 degrees C (97.7 degrees F). When assessing body temperature, it is important to take the age of the patient into consideration. Also, the reference point of 36.5 degrees C is inappropriate in older people, especially when diagnosing a febrile illness.

Central control of body temperature

PubMed Central

Morrison, Shaun F.

2016-01-01

Central neural circuits orchestrate the behavioral and autonomic repertoire that maintains body temperature during environmental temperature challenges and alters body temperature during the inflammatory response and behavioral states and in response to declining energy homeostasis. This review summarizes the central nervous system circuit mechanisms controlling the principal thermoeffectors for body temperature regulation: cutaneous vasoconstriction regulating heat loss and shivering and brown adipose tissue for thermogenesis. The activation of these thermoeffectors is regulated by parallel but distinct efferent pathways within the central nervous system that share a common peripheral thermal sensory input. The model for the neural circuit mechanism underlying central thermoregulatory control provides a useful platform for further understanding of the functional organization of central thermoregulation, for elucidating the hypothalamic circuitry and neurotransmitters involved in body temperature regulation, and for the discovery of novel therapeutic approaches to modulating body temperature and energy homeostasis. PMID:27239289

Central control of body temperature.

PubMed

Morrison, Shaun F

2016-01-01

Central neural circuits orchestrate the behavioral and autonomic repertoire that maintains body temperature during environmental temperature challenges and alters body temperature during the inflammatory response and behavioral states and in response to declining energy homeostasis. This review summarizes the central nervous system circuit mechanisms controlling the principal thermoeffectors for body temperature regulation: cutaneous vasoconstriction regulating heat loss and shivering and brown adipose tissue for thermogenesis. The activation of these thermoeffectors is regulated by parallel but distinct efferent pathways within the central nervous system that share a common peripheral thermal sensory input. The model for the neural circuit mechanism underlying central thermoregulatory control provides a useful platform for further understanding of the functional organization of central thermoregulation, for elucidating the hypothalamic circuitry and neurotransmitters involved in body temperature regulation, and for the discovery of novel therapeutic approaches to modulating body temperature and energy homeostasis.

Core body temperature in obesity.

PubMed

Heikens, Marc J; Gorbach, Alexander M; Eden, Henry S; Savastano, David M; Chen, Kong Y; Skarulis, Monica C; Yanovski, Jack A

2011-05-01

A lower core body temperature set point has been suggested to be a factor that could potentially predispose humans to develop obesity. We tested the hypothesis that obese individuals have lower core temperatures than those in normal-weight individuals. In study 1, nonobese [body mass index (BMI; in kg/m(2)) <30] and obese (BMI ≥30) adults swallowed wireless core temperature-sensing capsules, and we measured core temperatures continuously for 24 h. In study 2, normal-weight (BMI of 18-25) and obese subjects swallowed temperature-sensing capsules to measure core temperatures continuously for ≥48 h and kept activity logs. We constructed daily, 24-h core temperature profiles for analysis. Mean (±SE) daily core body temperature did not differ significantly between the 35 nonobese and 46 obese subjects (36.92 ± 0.03°C compared with 36.89 ± 0.03°C; P = 0.44). Core temperature 24-h profiles did not differ significantly between 11 normal-weight and 19 obese subjects (P = 0.274). Women had a mean core body temperature ≈0.23°C greater than that of men (36.99 ± 0.03°C compared with 36.76 ± 0.03°C; P < 0.0001). Obesity is not generally associated with a reduced core body temperature. It may be necessary to study individuals with function-altering mutations in core temperature-regulating genes to determine whether differences in the core body temperature set point affect the regulation of human body weight. These trials were registered at clinicaltrials.gov as NCT00428987 and NCT00266500.

Integration of body temperature into the analysis of energy expenditure in the mouse

PubMed Central

Abreu-Vieira, Gustavo; Xiao, Cuiying; Gavrilova, Oksana; Reitman, Marc L.

2015-01-01

Objectives We quantified the effect of environmental temperature on mouse energy homeostasis and body temperature. Methods The effect of environmental temperature (4–33 °C) on body temperature, energy expenditure, physical activity, and food intake in various mice (chow diet, high-fat diet, Brs3-/y, lipodystrophic) was measured using continuous monitoring. Results Body temperature depended most on circadian phase and physical activity, but also on environmental temperature. The amounts of energy expenditure due to basal metabolic rate (calculated via a novel method), thermic effect of food, physical activity, and cold-induced thermogenesis were determined as a function of environmental temperature. The measured resting defended body temperature matched that calculated from the energy expenditure using Fourier's law of heat conduction. Mice defended a higher body temperature during physical activity. The cost of the warmer body temperature during the active phase is 4–16% of total daily energy expenditure. Parameters measured in diet-induced obese and Brs3-/y mice were similar to controls. The high post-mortem heat conductance demonstrates that most insulation in mice is via physiological mechanisms. Conclusions At 22 °C, cold-induced thermogenesis is ∼120% of basal metabolic rate. The higher body temperature during physical activity is due to a higher set point, not simply increased heat generation during exercise. Most insulation in mice is via physiological mechanisms, with little from fur or fat. Our analysis suggests that the definition of the upper limit of the thermoneutral zone should be re-considered. Measuring body temperature informs interpretation of energy expenditure data and improves the predictiveness and utility of the mouse to model human energy homeostasis. PMID:26042200

Dinosaur Fossils Predict Body Temperatures

PubMed Central

Allen, Andrew P; Charnov, Eric L

2006-01-01

Perhaps the greatest mystery surrounding dinosaurs concerns whether they were endotherms, ectotherms, or some unique intermediate form. Here we present a model that yields estimates of dinosaur body temperature based on ontogenetic growth trajectories obtained from fossil bones. The model predicts that dinosaur body temperatures increased with body mass from approximately 25 °C at 12 kg to approximately 41 °C at 13,000 kg. The model also successfully predicts observed increases in body temperature with body mass for extant crocodiles. These results provide direct evidence that dinosaurs were reptiles that exhibited inertial homeothermy. PMID:16817695

Dinosaur fossils predict body temperatures.

PubMed

Gillooly, James F; Allen, Andrew P; Charnov, Eric L

2006-07-01

Perhaps the greatest mystery surrounding dinosaurs concerns whether they were endotherms, ectotherms, or some unique intermediate form. Here we present a model that yields estimates of dinosaur body temperature based on ontogenetic growth trajectories obtained from fossil bones. The model predicts that dinosaur body temperatures increased with body mass from approximately 25 degrees C at 12 kg to approximately 41 degrees C at 13,000 kg. The model also successfully predicts observed increases in body temperature with body mass for extant crocodiles. These results provide direct evidence that dinosaurs were reptiles that exhibited inertial homeothermy.

Do sex, body size and reproductive condition influence the thermal preferences of a large lizard? A study in Tupinambis merianae.

PubMed

Cecchetto, Nicolas Rodolfo; Naretto, Sergio

2015-10-01

Body temperature is a key factor in physiological processes, influencing lizard performances; and life history traits are expected to generate variability of thermal preferences in different individuals. Gender, body size and reproductive condition may impose specific requirements on preferred body temperatures. If these three factors have different physiological functions and thermal requirements, then the preferred temperature may represent a compromise that optimizes these physiological functions. Therefore, the body temperatures that lizards select in a controlled environment may reflect a temperature that maximizes their physiological needs. The tegu lizard Tupinambis merianae is one of the largest lizards in South America and has wide ontogenetic variation in body size and sexual dimorphism. In the present study we evaluate intraspecific variability of thermal preferences of T. merianae. We determined the selected body temperature and the rate at which males and females attain their selected temperature, in relation to body size and reproductive condition. We also compared the behavior in the thermal gradient between males and females and between reproductive condition of individuals. Our study show that T. merianae selected body temperature within a narrow range of temperatures variation in the laboratory thermal gradient, with 36.24±1.49°C being the preferred temperature. We observed no significant differences between sex, body size and reproductive condition in thermal preferences. Accordingly, we suggest that the evaluated categories of T. merianae have similar thermal requirements. Males showed higher rates to obtain heat than females and reproductive females, higher rates than non-reproductive ones females. Moreover, males and reproductive females showed a more dynamic behavior in the thermal gradient. Therefore, even though they achieve the same selected temperature, they do it differentially. Copyright © 2015 Elsevier Ltd. All rights reserved.

Metabolic heat production, heat loss and the circadian rhythm of body temperature in the rat.

PubMed

Refinetti, Roberto

2003-05-01

Metabolic heat production (calculated from oxygen consumption), dry heat loss (measured in a calorimeter) and body temperature (measured by telemetry) were recorded simultaneously at 6 min intervals over five consecutive days in rats maintained in constant darkness. Robust circadian rhythmicity (confirmed by chi square periodogram analysis) was observed in all three variables. The rhythm of heat production was phase-advanced by about half an hour in relation to the body temperature rhythm, whereas the rhythm of heat loss was phase-delayed by about half an hour. The balance of heat production and heat loss exhibited a daily oscillation 180 deg out of phase with the oscillation in body temperature. Computations indicated that the amount of heat associated with the generation of the body temperature rhythm (1.6 kJ) corresponds to less than 1 % of the total daily energy budget (172 kJ) in this species. Because of the small magnitude of the fraction of heat balance associated with the body temperature rhythm, it is likely that the daily oscillation in heat balance has a very slow effect on body temperature, thus accounting for the 180 deg phase difference between the rhythms of heat balance and body temperature.

Inverse relationship of baseline body temperature and outcome between ischemic stroke patients treated and not treated with thrombolysis: the Bergen stroke study.

PubMed

Naess, Halvor; Idicula, T; Lagallo, N; Brogger, J; Waje-Andreassen, U; Thomassen, L

2010-12-01

High body temperature may promote clot lysis whereas low body temperature is neuroprotective in patients with cerebral infarction. We hypothesized that high body temperature is associated with favorable outcome in patients treated with tissue plasminogen activator (tPA) and that low body temperature is associated with favorable outcome in patients not treated with tPA. Patients (n = 111) who were treated with tPA and patients (n = 139) who were not treated with tPA, but presented within 6 h of stroke onset were included. Patients with no temperature measurements within 6 h of stroke onset were excluded. National Institute of Health Stroke Scale (NIHSS) score was obtained on admission. Modified Rankin score (mRS) was obtained after 1 week. Favorable outcome was defined as mRS 0-2 and unfavorable outcome as mRS 3-6. On logistic regression analysis, high body temperature was independently associated with favorable outcome among patients treated with tPA (OR = 3.7, P = 0.009) and low body temperature was independently associated with favorable prognosis among patients not treated with tPA (OR = 2.0, P = 0.042). Our study suggests that the effect of high body temperature on clot lysis is more important than the neuroprotective effect of low body temperature in the early phase after cerebral infarction treated with tPA. Copyright © 2010 The Authors. Journal compilation © 2010 Blackwell Munksgaard.

Radiant Temperature Nulling Radiometer

NASA Technical Reports Server (NTRS)

Ryan, Robert (Inventor)

2003-01-01

A self-calibrating nulling radiometer for non-contact temperature measurement of an object, such as a body of water, employs a black body source as a temperature reference, an optomechanical mechanism, e.g., a chopper, to switch back and forth between measuring the temperature of the black body source and that of a test source, and an infrared detection technique. The radiometer functions by measuring radiance of both the test and the reference black body sources; adjusting the temperature of the reference black body so that its radiance is equivalent to the test source; and, measuring the temperature of the reference black body at this point using a precision contact-type temperature sensor, to determine the radiative temperature of the test source. The radiation from both sources is detected by an infrared detector that converts the detected radiation to an electrical signal that is fed with a chopper reference signal to an error signal generator, such as a synchronous detector, that creates a precision rectified signal that is approximately proportional to the difference between the temperature of the reference black body and that of the test infrared source. This error signal is then used in a feedback loop to adjust the reference black body temperature until it equals that of the test source, at which point the error signal is nulled to zero. The chopper mechanism operates at one or more Hertz allowing minimization of l/f noise. It also provides pure chopping between the black body and the test source and allows continuous measurements.

Differences in the thermal physiology of adult Yarrow's spiny lizards (Sceloporus jarrovii) in relation to sex and body size.

PubMed

Beal, Martin S; Lattanzio, Matthew S; Miles, Donald B

2014-11-01

Sexual size dimorphism (SSD) is often assumed to reflect the phenotypic consequences of differential selection operating on each sex. Species that exhibit SSD may also show intersexual differences in other traits, including field-active body temperatures, preferred temperatures, and locomotor performance. For these traits, differences may be correlated with differences in body size or reflect sex-specific trait optima. Male and female Yarrow's spiny lizards, Sceloporus jarrovii, in a population in southeastern Arizona exhibit a difference in body temperature that is unrelated to variation in body size. The observed sexual variation in body temperature may reflect divergence in thermal physiology between the sexes. To test this hypothesis, we measured the preferred body temperatures of male and female lizards when recently fed and fasted. We also estimated the thermal sensitivity of stamina at seven body temperatures. Variation in these traits provided an opportunity to determine whether body size or sex-specific variation unrelated to size shaped their thermal physiology. Female lizards, but not males, preferred a lower body temperature when fasted, and this pattern was unrelated to body size. Larger individuals exhibited greater stamina, but we detected no significant effect of sex on the shape or height of the thermal performance curves. The thermal preference of males and females in a thermal gradient exceeded the optimal temperature for performance in both sexes. Our findings suggest that differences in thermal physiology are both sex- and size-based and that peak performance at low body temperatures may be adaptive given the reproductive cycles of this viviparous species. We consider the implications of our findings for the persistence of S. jarrovii and other montane ectotherms in the face of climate warming.

Differences in the thermal physiology of adult Yarrow's spiny lizards (Sceloporus jarrovii) in relation to sex and body size

PubMed Central

Beal, Martin S; Lattanzio, Matthew S; Miles, Donald B

2014-01-01

Sexual size dimorphism (SSD) is often assumed to reflect the phenotypic consequences of differential selection operating on each sex. Species that exhibit SSD may also show intersexual differences in other traits, including field-active body temperatures, preferred temperatures, and locomotor performance. For these traits, differences may be correlated with differences in body size or reflect sex-specific trait optima. Male and female Yarrow's spiny lizards, Sceloporus jarrovii, in a population in southeastern Arizona exhibit a difference in body temperature that is unrelated to variation in body size. The observed sexual variation in body temperature may reflect divergence in thermal physiology between the sexes. To test this hypothesis, we measured the preferred body temperatures of male and female lizards when recently fed and fasted. We also estimated the thermal sensitivity of stamina at seven body temperatures. Variation in these traits provided an opportunity to determine whether body size or sex-specific variation unrelated to size shaped their thermal physiology. Female lizards, but not males, preferred a lower body temperature when fasted, and this pattern was unrelated to body size. Larger individuals exhibited greater stamina, but we detected no significant effect of sex on the shape or height of the thermal performance curves. The thermal preference of males and females in a thermal gradient exceeded the optimal temperature for performance in both sexes. Our findings suggest that differences in thermal physiology are both sex- and size-based and that peak performance at low body temperatures may be adaptive given the reproductive cycles of this viviparous species. We consider the implications of our findings for the persistence of S. jarrovii and other montane ectotherms in the face of climate warming. PMID:25540684

Regulation of body temperature and neuroprotection by endogenous interleukin-6 in cerebral ischemia.

PubMed

Herrmann, Oliver; Tarabin, Victoria; Suzuki, Shigeaki; Attigah, Nicolas; Coserea, Irinel; Schneider, Armin; Vogel, Johannes; Prinz, Simone; Schwab, Stefan; Monyer, Hannah; Brombacher, Frank; Schwaninger, Markus

2003-04-01

Although the function of fever is still unclear, it is now beyond doubt that body temperature influences the outcome of brain damage. An elevated body temperature is often found in stroke patients and denotes a bad prognosis. However, the pathophysiologic basis and treatment options of elevated body temperature after stroke are still unknown. Cerebral ischemia rapidly induced neuronal interleukin-6 (IL-6) expression in mice. In IL-6-deficient mice, body temperature was markedly decreased after middle cerebral artery occlusion (MCAO), but infarct size was comparable to that in control mice. If body temperature was controlled by external warming after MCAO, IL-6-deficient mice had a reduced survival, worse neurologic status, and larger infarcts than control animals. In cell culture, IL-6 exerted an antiapoptotic and neuroprotective effect. These data suggest that IL-6 is a key regulator of body temperature and an endogenous neuroprotectant in cerebral ischemia. Neuroprotective properties apparently compensate for its pyretic action after MCAO and enhance the safety of this endogenous pyrogen.

Effects of Cooling During Exercise on Thermoregulatory Responses of Men With Paraplegia.

PubMed

Bongers, Coen C W G; Eijsvogels, Thijs M H; van Nes, Ilse J W; Hopman, Maria T E; Thijssen, Dick H J

2016-05-01

People with spinal cord injury (SCI) have an altered afferent input to the thermoregulatory center, resulting in a reduced efferent response (vasomotor control and sweating capacity) below the level of the lesion. Consequently, core body temperature rises more rapidly during exercise in individuals with SCI compared with people who are able-bodied. Cooling strategies may reduce the thermophysiological strain in SCI. The aim of this study was to examine the effects of a cooling vest on the core body temperature response of people with a thoracic SCI during submaximal exercise. Ten men (mean age=44 years, SD=11) with a thoracic lesion (T4-T5 or below) participated in this randomized crossover study. Participants performed two 45-minute exercise bouts at 50% maximal workload (ambient temperature 25°C), with participants randomized to a group wearing a cooling vest or a group wearing no vest (separate days). Core body temperature and skin temperature were continuously measured, and thermal sensation was assessed every 3 minutes. Exercise resulted in an increased core body temperature, skin temperature, and thermal sensation, whereas cooling did not affect core body temperature. The cooling vest effectively decreased skin temperature, increased the core-to-trunk skin temperature gradient, and tended to lower thermal sensation compared with the control condition. The lack of differences in core body temperature among conditions may be a result of the relative moderate ambient temperature in which the exercise was performed. Despite effectively lowering skin temperature and increasing the core-to-trunk skin temperature gradient, there was no impact of the cooling vest on the exercise-induced increase in core body temperature in men with low thoracic SCI. © 2016 American Physical Therapy Association.

Increased benefit of alteplase in patients with ischemic stroke and a high body temperature.

PubMed

de Ridder, Inger; den Hertog, Heleen; van Gemert, Maarten; Dippel, Diederik; van der Worp, Bart

2013-01-01

In observational studies, a high body temperature has been associated with unfavorable outcome. In in vitro studies, the fibrinolytic activity of alteplase decreased 5% per degree Celsius reduction in temperature. The modifying effect of body temperature on treatment with alteplase in patients with acute ischemic stroke is unclear. We assessed the influence of baseline body temperature on the effect of alteplase on functional outcome in patients with acute ischemic stroke, included in the Paracetamol (Acetaminophen) in Stroke (PAIS) trial. PAIS was a randomized, double-blind clinical trial to assess the effect of high-dose paracetamol on functional outcome in patients with acute stroke. For this study, we selected all patients with ischemic stroke and randomization within 6 h of symptom onset. We estimated the effect of treatment with alteplase on the modified Rankin Scale score at 3 months with ordinal logistic regression, stratified by baseline body temperature. We made adjustments for confounding factors and expressed associations as adjusted odds ratios (aOR) with 95% confidence intervals (CI). We also tested for interaction between treatment with alteplase and body temperature. We included 647 of the 1,400 patients in PAIS in our study. Treatment with alteplase was associated with improved functional outcome at 3 months (aOR 1.51, 95% CI 1.09-2.08). In the 286 patients (44%) with a baseline body temperature of 37.0°C or higher, alteplase was associated with a larger effect (aOR 2.13, 95% CI 1.28-3.45) than in patients with a temperature below 37.0°C (aOR 1.11, 95% CI 0.71-1.69). A test for interaction between body temperature and alteplase did not reach statistical significance (p = 0.18). Patients with ischemic stroke and a high body temperature may have a larger benefit of treatment with alteplase than patients with lower body temperatures. These findings are in line with those from in vitro studies, in which lowering temperature decreased the fibrinolytic activity of the enzyme alteplase. This interaction should be explored further in randomized clinical trials of thrombolytic therapy or modification of body temperature. Trials of therapeutic hypothermia should be controlled for treatment with thrombolytics, and trials of thrombolytic treatment should consider body temperature as a potential effect modifier. Copyright © 2013 S. Karger AG, Basel.

Effect of air gap on apparent temperature of body wearing various sizes of T-shirt

NASA Astrophysics Data System (ADS)

Takatera, M.; Uchiyama, E.; Zhu, C.; Kim, KO; Ishizawa, H.

2017-10-01

We investigated the effect of air gap on the apparent temperature. Using the developed thermocouple fabric and a thermal manikin, we measured temperature distribution of the measuring garments due to the change of T-shirt sizes. We were able to measure the apparent temperature distribution at points near a body while wearing different sizes of T-shirts. It was observed that the temperature distribution depending on different air gap between clothing and body. The apparent temperature depends on garment size and place. The effect of air gap on apparent temperature of body was experimentally confirmed.

Heart rate reveals torpor at high body temperatures in lowland tropical free-tailed bats.

PubMed

O'Mara, M Teague; Rikker, Sebastian; Wikelski, Martin; Ter Maat, Andries; Pollock, Henry S; Dechmann, Dina K N

2017-12-01

Reduction in metabolic rate and body temperature is a common strategy for small endotherms to save energy. The daily reduction in metabolic rate and heterothermy, or torpor, is particularly pronounced in regions with a large variation in daily ambient temperature. This applies most strongly in temperate bat species (order Chiroptera), but it is less clear how tropical bats save energy if ambient temperatures remain high. However, many subtropical and tropical species use some daily heterothermy on cool days. We recorded the heart rate and the body temperature of free-ranging Pallas' mastiff bats ( Molossus molossus ) in Gamboa, Panamá, and showed that these individuals have low field metabolic rates across a wide range of body temperatures that conform to high ambient temperature. Importantly, low metabolic rates in controlled respirometry trials were best predicted by heart rate, and not body temperature . Molossus molossus enter torpor-like states characterized by low metabolic rate and heart rates at body temperatures of 32°C, and thermoconform across a range of temperatures. Flexible metabolic strategies may be far more common in tropical endotherms than currently known.

Heart rate reveals torpor at high body temperatures in lowland tropical free-tailed bats

PubMed Central

Rikker, Sebastian; Wikelski, Martin; Ter Maat, Andries

2017-01-01

Reduction in metabolic rate and body temperature is a common strategy for small endotherms to save energy. The daily reduction in metabolic rate and heterothermy, or torpor, is particularly pronounced in regions with a large variation in daily ambient temperature. This applies most strongly in temperate bat species (order Chiroptera), but it is less clear how tropical bats save energy if ambient temperatures remain high. However, many subtropical and tropical species use some daily heterothermy on cool days. We recorded the heart rate and the body temperature of free-ranging Pallas' mastiff bats (Molossus molossus) in Gamboa, Panamá, and showed that these individuals have low field metabolic rates across a wide range of body temperatures that conform to high ambient temperature. Importantly, low metabolic rates in controlled respirometry trials were best predicted by heart rate, and not body temperature. Molossus molossus enter torpor-like states characterized by low metabolic rate and heart rates at body temperatures of 32°C, and thermoconform across a range of temperatures. Flexible metabolic strategies may be far more common in tropical endotherms than currently known. PMID:29308259

Plasticity of Performance Curves Can Buffer Reaction Rates from Body Temperature Variation in Active Endotherms.

PubMed

Seebacher, Frank; Little, Alexander G

2017-01-01

Endotherms regulate their core body temperature by adjusting metabolic heat production and insulation. Endothermic body temperatures are therefore relatively stable compared to external temperatures. The thermal sensitivity of biochemical reaction rates is thought to have co-evolved with body temperature regulation so that optimal reaction rates occur at the regulated body temperature. However, recent data show that core body temperatures even of non-torpid endotherms fluctuate considerably. Additionally, peripheral temperatures can be considerably lower and more variable than core body temperatures. Here we discuss whether published data support the hypothesis that thermal performance curves of physiological reaction rates are plastic so that performance is maintained despite variable body temperatures within active (non-torpid) endotherms, and we explore mechanisms that confer plasticity. There is evidence that thermal performance curves in tissues that experience thermal fluctuations can be plastic, although this question remains relatively unexplored for endotherms. Mechanisms that alter thermal responses locally at the tissue level include transient potential receptor ion channels (TRPV and TRPM) and the AMP-activated protein kinase (AMPK) both of which can influence metabolism and energy expenditure. Additionally, the thermal sensitivity of processes that cause post-transcriptional RNA degradation can promote the relative expression of cold-responsive genes. Endotherms can respond to environmental fluctuations similarly to ectotherms, and thermal plasticity complements core body temperature regulation to increase whole-organism performance. Thermal plasticity is ancestral to endothermic thermoregulation, but it has not lost its selective advantage so that modern endotherms are a physiological composite of ancestral ectothermic and derived endothermic traits.

Plasticity of Performance Curves Can Buffer Reaction Rates from Body Temperature Variation in Active Endotherms

PubMed Central

Seebacher, Frank; Little, Alexander G.

2017-01-01

Endotherms regulate their core body temperature by adjusting metabolic heat production and insulation. Endothermic body temperatures are therefore relatively stable compared to external temperatures. The thermal sensitivity of biochemical reaction rates is thought to have co-evolved with body temperature regulation so that optimal reaction rates occur at the regulated body temperature. However, recent data show that core body temperatures even of non-torpid endotherms fluctuate considerably. Additionally, peripheral temperatures can be considerably lower and more variable than core body temperatures. Here we discuss whether published data support the hypothesis that thermal performance curves of physiological reaction rates are plastic so that performance is maintained despite variable body temperatures within active (non-torpid) endotherms, and we explore mechanisms that confer plasticity. There is evidence that thermal performance curves in tissues that experience thermal fluctuations can be plastic, although this question remains relatively unexplored for endotherms. Mechanisms that alter thermal responses locally at the tissue level include transient potential receptor ion channels (TRPV and TRPM) and the AMP-activated protein kinase (AMPK) both of which can influence metabolism and energy expenditure. Additionally, the thermal sensitivity of processes that cause post-transcriptional RNA degradation can promote the relative expression of cold-responsive genes. Endotherms can respond to environmental fluctuations similarly to ectotherms, and thermal plasticity complements core body temperature regulation to increase whole-organism performance. Thermal plasticity is ancestral to endothermic thermoregulation, but it has not lost its selective advantage so that modern endotherms are a physiological composite of ancestral ectothermic and derived endothermic traits. PMID:28824463

Role of leptin in body temperature regulation and lipid metabolism following splenectomy.

PubMed

Rosa, T S; Amorim, C E N; Barros, C C; Haro, A S; Wasinski, F; Russo, F J; Bacurau, R F P; Araujo, R C

2015-12-01

The physiological changes in serum triglycerides and body temperature that are induced by splenectomy are poorly understood. Therefore, the aim of this study was to investigate parameters related to lipid and glucose metabolism, as well as thermoregulation, in splenectomized mice. Splenectomized and sham-operated WT mice (C57Bl/6) and ob/ob mice were randomly divided and treated with a standard or high fat diet, and several metabolic parameters and the body temperature were investigated. Splenectomy induced a significant increase in triglyceride levels regardless of the diet. It was found that the splenectomized WT mice showed greater serum leptin and insulin levels compared with the sham-operated mice. Additionally, the body temperatures of the splenectomized WT mice were greater than the body temperatures of the control animals regardless of diet; this result too was observed without any significant change in the temperature of the splenectomized ob/ob animals. The results suggest that splenectomy interferes with serum triglyceride metabolism and body temperature regardless of the fat content in the diet and that leptin is involved in the regulation of body temperature related to splenectomy.

Monitoring the body temperature of cows and calves using video recordings from an infrared thermography camera.

PubMed

Hoffmann, Gundula; Schmidt, Mariana; Ammon, Christian; Rose-Meierhöfer, Sandra; Burfeind, Onno; Heuwieser, Wolfgang; Berg, Werner

2013-06-01

The aim of this study was to assess the variability of temperatures measured by a video-based infrared camera (IRC) in comparison to rectal and vaginal temperatures. The body surface temperatures of cows and calves were measured contactless at different body regions using videos from the IRC. Altogether, 22 cows and 9 calves were examined. The differences of the measured IRC temperatures among the body regions, i.e. eye (mean: 37.0 °C), back of the ear (35.6 °C), shoulder (34.9 °C) and vulva (37.2 °C), were significant (P < 0.01), except between eye and vulva (P = 0.99). The quartile ranges of the measured IRC temperatures at the 4 above mentioned regions were between 1.2 and 1.8 K. Of the investigated body regions the eye and the back of the ear proved to be suitable as practical regions for temperature monitoring. The temperatures of these 2 regions could be gained by the use of the maximum temperatures of the head and body area. Therefore, only the maximum temperatures of both areas were used for further analysis. The data analysis showed an increase for the maximum temperature measured by IRC at head and body area with an increase of rectal temperature in cows and calves. The use of infrared thermography videos has the advantage to analyze more than 1 picture per animal in a short period of time, and shows potential as a monitoring system for body temperatures in cattle.

Effect of danofloxacin and tilmicosin on body temperatures of beef calves with pneumonia experimentally induced by inoculation with Mannheimia haemolytica.

PubMed

Fajt, Virginia R; Apley, Michael D; Brogden, Kim A; Skogerboe, Terry L; Shostrom, Valerie K; Chin, Ya-Lin

2004-05-01

To examine effects of danofloxacin and tilmicosin on continuously recorded body temperature in beef calves with pneumonia experimentally induced by inoculation of Mannheimia haemolytica. 41 Angus-cross heifers (body weight, 160 to 220 kg) without a recent history of respiratory tract disease or antimicrobial treatment, all from a single ranch. Radiotransmitters were implanted intravaginally in each calf. Pneumonia was induced intrabronchially by use of logarithmic-phase cultures of M. haemolytica. At 21 hours after inoculation, calves were treated with saline (0.9% NaCl) solution, danofloxacin, or tilmicosin. Body temperature was monitored from 66 hours before inoculation until 72 hours after treatment. Area under the curve (AUC) of the temperature-time plot and mean temperature were calculated for 3-hour intervals and compared among treatment groups. The AUCs for 3-hour intervals did not differ significantly among treatment groups for any of the time periods. Analysis of the mean temperature for 3-hour intervals revealed significantly higher temperatures at most time periods for saline-treated calves, compared with temperatures for antimicrobial-treated calves; however, we did not detect significant differences between the danofloxacin- and tilmicosin-treated calves. The circadian rhythm of temperatures before exposure was detected again approximately 48 hours after bacterial inoculation. Danofloxacin and tilmicosin did not differ in their effect on mean body temperature for 3-hour intervals but significantly decreased body temperature, compared with body temperature in saline-treated calves. Normal daily variation in body temperature must be considered in the face of respiratory tract disease during clinical evaluation of feedlot cattle.

Prediction of human core body temperature using non-invasive measurement methods.

PubMed

Niedermann, Reto; Wyss, Eva; Annaheim, Simon; Psikuta, Agnes; Davey, Sarah; Rossi, René Michel

2014-01-01

The measurement of core body temperature is an efficient method for monitoring heat stress amongst workers in hot conditions. However, invasive measurement of core body temperature (e.g. rectal, intestinal, oesophageal temperature) is impractical for such applications. Therefore, the aim of this study was to define relevant non-invasive measures to predict core body temperature under various conditions. We conducted two human subject studies with different experimental protocols, different environmental temperatures (10 °C, 30 °C) and different subjects. In both studies the same non-invasive measurement methods (skin temperature, skin heat flux, heart rate) were applied. A principle component analysis was conducted to extract independent factors, which were then used in a linear regression model. We identified six parameters (three skin temperatures, two skin heat fluxes and heart rate), which were included for the calculation of two factors. The predictive value of these factors for core body temperature was evaluated by a multiple regression analysis. The calculated root mean square deviation (rmsd) was in the range from 0.28 °C to 0.34 °C for all environmental conditions. These errors are similar to previous models using non-invasive measures to predict core body temperature. The results from this study illustrate that multiple physiological parameters (e.g. skin temperature and skin heat fluxes) are needed to predict core body temperature. In addition, the physiological measurements chosen in this study and the algorithm defined in this work are potentially applicable as real-time core body temperature monitoring to assess health risk in broad range of working conditions.

FDTD analysis of body-core temperature elevation in children and adults for whole-body exposure.

PubMed

Hirata, Akimasa; Asano, Takayuki; Fujiwara, Osamu

2008-09-21

The temperature elevations in anatomically based human phantoms of an adult and a 3-year-old child were calculated for radio-frequency whole-body exposure. Thermoregulation in children, however, has not yet been clarified. In the present study, we developed a computational thermal model of a child that is reasonable for simulating body-core temperature elevation. Comparison of measured and simulated temperatures revealed thermoregulation in children to be similar to that of adults. Based on this finding, we calculated the body-core temperature elevation in a 3-year-old child and an adult for plane-wave exposure at the basic restriction in the international guidelines. The body-core temperature elevation in the 3-year-old child phantom was 0.03 degrees C at a whole-body-averaged specific absorption rate of 0.08 W kg(-1), which was 35% smaller than in the adult female. This difference is attributed to the child's higher body surface area-to-mass ratio.

Temperature-Dependent Growth and Fission Rate Plasticity Drive Seasonal and Geographic Changes in Body Size in a Clonal Sea Anemone.

PubMed

Ryan, Will H

2018-02-01

The temperature-size rule is a commonly observed pattern where adult body size is negatively correlated with developmental temperature. In part, this may occur as a consequence of allometric scaling, where changes in the ratio of surface area to mass limit oxygen diffusion as body size increases. As oxygen demand increases with temperature, a smaller body should be favored as temperature increases. For clonal animals, small changes in growth and/or fission rate can rapidly alter the average body size of clonal descendants. Here I test the hypothesis that the clonal sea anemone Diadumene lineata is able to track an optimal body size through seasonal temperature changes using fission rate plasticity. Individuals from three regions (Florida, Georgia, and Massachusetts) across the species' latitudinal range were grown in a year-long reciprocal common garden experiment mimicking seasonal temperature changes at three sites. Average body size was found to be smaller and fission rates higher in warmer conditions, consistent with the temperature-size rule pattern. However, seasonal size and fission patterns reflect a complex interaction between region-specific thermal reaction norms and the local temperature regime. These details provide insight into both the range of conditions required for oxygen limitation to contribute to a negative correlation between body size and temperature and the role that fission rate plasticity can play in tracking a rapidly changing optimal phenotype.

Patterns of activity and body temperature of Aldabra giant tortoises in relation to environmental temperature.

PubMed

Falcón, Wilfredo; Baxter, Rich P; Furrer, Samuel; Bauert, Martin; Hatt, Jean-Michel; Schaepman-Strub, Gabriela; Ozgul, Arpat; Bunbury, Nancy; Clauss, Marcus; Hansen, Dennis M

2018-02-01

We studied the temperature relations of wild and zoo Aldabra giant tortoises ( Aldabrachelys gigantea ) focusing on (1) the relationship between environmental temperature and tortoise activity patterns ( n  = 8 wild individuals) and (2) on tortoise body temperature fluctuations, including how their core and external body temperatures vary in relation to different environmental temperature ranges (seasons; n  = 4 wild and n  = 5 zoo individuals). In addition, we surveyed the literature to review the effect of body mass on core body temperature range in relation to environmental temperature in the Testudinidae. Diurnal activity of tortoises was bimodally distributed and influenced by environmental temperature and season. The mean air temperature at which activity is maximized was 27.9°C, with a range of 25.8-31.7°C. Furthermore, air temperature explained changes in the core body temperature better than did mass, and only during the coldest trial, did tortoises with higher mass show more stable temperatures. Our results, together with the overall Testudinidae overview, suggest that, once variation in environmental temperature has been taken into account, there is little effect of mass on the temperature stability of tortoises. Moreover, the presence of thermal inertia in an individual tortoise depends on the environmental temperatures, and we found no evidence for inertial homeothermy. Finally, patterns of core and external body temperatures in comparison with environmental temperatures suggest that Aldabra giant tortoises act as mixed conformer-regulators. Our study provides a baseline to manage the thermal environment of wild and rewilded populations of an important island ecosystem engineer species in an era of climate change.

Do acute phase markers explain body temperature and brain temperature after ischemic stroke?

PubMed Central

Whiteley, William N.; Thomas, Ralph; Lowe, Gordon; Rumley, Ann; Karaszewski, Bartosz; Armitage, Paul; Marshall, Ian; Lymer, Katherine; Dennis, Martin

2012-01-01

Objective: Both brain and body temperature rise after stroke but the cause of each is uncertain. We investigated the relationship between circulating markers of inflammation with brain and body temperature after stroke. Methods: We recruited patients with acute ischemic stroke and measured brain temperature at hospital admission and 5 days after stroke with multivoxel magnetic resonance spectroscopic imaging in normal brain and the acute ischemic lesion (defined by diffusion-weighted imaging [DWI]). We measured body temperature with digital aural thermometers 4-hourly and drew blood daily to measure interleukin-6, C-reactive protein, and fibrinogen, for 5 days after stroke. Results: In 44 stroke patients, the mean temperature in DWI-ischemic brain soon after admission was 38.4°C (95% confidence interval [CI] 38.2–38.6), in DWI-normal brain was 37.7°C (95% CI 37.6–37.7), and mean body temperature was 36.6°C (95% CI 36.3–37.0). Higher mean levels of interleukin-6, C-reactive protein, and fibrinogen were associated with higher temperature in DWI-normal brain at admission and 5 days, and higher overall mean body temperature, but only with higher temperature in DWI-ischemic brain on admission. Conclusions: Systemic inflammation after stroke is associated with elevated temperature in normal brain and the body but not with later ischemic brain temperature. Elevated brain temperature is a potential mechanism for the poorer outcome observed in stroke patients with higher levels of circulating inflammatory markers. PMID:22744672

Decreases in beetle body size linked to climate change and warming temperatures.

PubMed

Tseng, Michelle; Kaur, Katrina M; Soleimani Pari, Sina; Sarai, Karnjit; Chan, Denessa; Yao, Christine H; Porto, Paula; Toor, Anmol; Toor, Harpawantaj S; Fograscher, Katrina

2018-05-01

Body size is a fundamental ecological trait and is correlated with population dynamics, community structure and function, and ecosystem fluxes. Laboratory data from broad taxonomic groups suggest that a widespread response to a warming world may be an overall decrease in organism body size. However, given the myriad of biotic and abiotic factors that can also influence organism body size in the wild, it is unclear whether results from these laboratory assays hold in nature. Here we use datasets spanning 30 to 100 years to examine whether the body size of wild-caught beetles has changed over time, whether body size changes are correlated with increased temperatures, and we frame these results using predictions derived from a quantitative review of laboratory responses of 22 beetle species to temperature. We found that 95% of laboratory-reared beetles decreased in size with increased rearing temperature, with larger-bodied species shrinking disproportionately more than smaller-bodied beetles. In addition, the museum datasets revealed that larger-bodied beetle species have decreased in size over time, that mean beetle body size explains much of the interspecific variation in beetle responses to temperature, and that long-term beetle size changes are explained by increases in autumn temperature and decreases in spring temperature in this region. Our data demonstrate that the relationship between body size and temperature of wild-caught beetles matches relatively well with results from laboratory studies, and that variation in this relationship is largely explained by interspecific variation in mean beetle body size. This long-term beetle dataset is one of the most comprehensive arthropod body size datasets compiled to date, it improves predictions regarding the shrinking of organisms with global climate change, and together with the meta-analysis data, call for new hypotheses to explain why larger-bodied organisms may be more sensitive to temperature. © 2018 The Authors. Journal of Animal Ecology © 2018 British Ecological Society.

METHOD FOR TREATING GRAPHITE PRODUCT

DOEpatents

Gurinsky, D.H.

1961-08-01

A method is described for treating a carbon body with a carbonyl consisting of nickel, iron, and mixtures thereof. The carbonyl is decomposed in a non-oxidizing atmosphere into a mixture of the metal and carbon monoxide on the surface of a carbon body heated to above the decomposition point of the carbonyl. The temperature is increased of the carbon body to an elevated temperature above the point at which a liquid eutectic mixture of the metal and carbon of the carbon body is formed at the surface and below that at which substantial carburization occurs. The elevated temperature is maintained whereby the liquid mixture flows over the surface of the carbon body. The carbon body is cooled below the decomposition temperature of the carbonyl of the metal and to a temperature suitable for forming the carbonyl of the metal. The carbon body is then contacted with carbon monoxide at the carbonyl-forming temperature, whereby carbonyl of the metal is formed in and on the carbon body. The carbonyl is removed from the carbon body by gasifying the carbonyl. (AEC)

Core body temperature in obesity123

PubMed Central

Heikens, Marc J; Gorbach, Alexander M; Eden, Henry S; Savastano, David M; Chen, Kong Y; Skarulis, Monica C

2011-01-01

Background: A lower core body temperature set point has been suggested to be a factor that could potentially predispose humans to develop obesity. Objective: We tested the hypothesis that obese individuals have lower core temperatures than those in normal-weight individuals. Design: In study 1, nonobese [body mass index (BMI; in kg/m2) <30] and obese (BMI ≥30) adults swallowed wireless core temperature–sensing capsules, and we measured core temperatures continuously for 24 h. In study 2, normal-weight (BMI of 18–25) and obese subjects swallowed temperature-sensing capsules to measure core temperatures continuously for ≥48 h and kept activity logs. We constructed daily, 24-h core temperature profiles for analysis. Results: Mean (±SE) daily core body temperature did not differ significantly between the 35 nonobese and 46 obese subjects (36.92 ± 0.03°C compared with 36.89 ± 0.03°C; P = 0.44). Core temperature 24-h profiles did not differ significantly between 11 normal-weight and 19 obese subjects (P = 0.274). Women had a mean core body temperature ≈0.23°C greater than that of men (36.99 ± 0.03°C compared with 36.76 ± 0.03°C; P < 0.0001). Conclusions: Obesity is not generally associated with a reduced core body temperature. It may be necessary to study individuals with function-altering mutations in core temperature–regulating genes to determine whether differences in the core body temperature set point affect the regulation of human body weight. These trials were registered at clinicaltrials.gov as NCT00428987 and NCT00266500. PMID:21367952

Circadian rhythms of body temperature and locomotor activity in the antelope ground squirrel, Ammospermophilus leucurus.

PubMed

Refinetti, Roberto; Kenagy, G J

2018-02-01

We studied circadian rhythms of body temperature and locomotor activity in antelope ground squirrels (Ammospermophilus leucurus) under laboratory conditions of a 12L:12D light-dark cycle and in constant darkness. Antelope ground squirrels are diurnally active and, exceptionally among ground squirrels and other closely related members of the squirrel family in general, they do not hibernate. Daily oscillations in body temperature consisted of a rise in temperature during the daytime activity phase of the circadian cycle and a decrease in temperature during the nighttime rest phase. The body temperature rhythms were robust (71% of maximal strength) with a daily range of oscillation of 4.6°C, a daytime mean of 38.7°C, and a nighttime mean of 34.1°C (24-h overall mean 36.4°C). The body temperature rhythm persisted in continuous darkness with a free-running period of 24.2h. This pattern is similar to that of hibernating species of ground squirrels but with a wave form more similar to that of non-hibernating rodents. Daily oscillations in body temperature were correlated with individual bouts of activity, but daytime temperatures were higher than nighttime temperatures even when comparing short episodes of nocturnal activity that were as intense as diurnal activity. This suggests that although muscular thermogenesis associated with locomotor activity can modify the level of body temperature, the circadian rhythm of body temperature is not simply a consequence of the circadian rhythm of activity. Copyright © 2018 Elsevier Ltd. All rights reserved.

Body temperature and major neurological improvement in tPA-treated stroke patients.

PubMed

Kvistad, C E; Thomassen, L; Waje-Andreassen, U; Logallo, N; Naess, H

2014-05-01

Major neurological improvement (MNI) at 24 hours represents a marker of early recanalization in ischaemic stroke. Although low body temperature is considered neuroprotective in cerebral ischaemia, some studies have suggested that higher body temperature may promote clot lysis in the acute phase of ischaemic stroke. We hypothesized that higher body temperature was associated with MNI in severe stroke patients treated with tPA, suggesting a beneficial effect of higher body temperature on clot lysis and recanalization. Patients with ischaemic stroke or transient ischaemic attack (TIA) treated with tPA between February 2006 and August 2012 were prospectively included and retrospectively analysed. Body temperature was measured upon admission. MNI was defined by a ≥8 point improvement in NIHSS score at 24 hours as compared to NIHSS score on admission. No significant improvement (no-MNI) was defined by either an increase in NIHSS score or a decrease of ≤2 points at 24 hours in patients with an admission NIHSS score of ≥8. Of the 2351 patients admitted with ischaemic stroke or TIA, 347 patients (14.8%) were treated with tPA. A total of 32 patients (9.2%) had MNI and 56 patients (16.1%) had no-MNI. Patients with MNI had higher body temperatures compared with patients with no-MNI (36.7°C vs 36.3°C, P = 0.004). Higher body temperature was independently associated with MNI when adjusted for confounders (OR 5.16, P = 0.003). Higher body temperature was independently associated with MNI in severe ischaemic stroke patients treated with tPA. This may suggest a beneficial effect of higher body temperature on clot lysis and recanalization. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Monitoring of the bed time body temperature and body weight to prevent the occurrence of heat stroke in the Royal Thai Army recruits, Lopburi Province, Thailand.

PubMed

Pumchandh, Norawee; Tedsana, Vanida; Ngow, Supak; Rangsin, Ram; Aimpun, Pote; Mungthin, Mathirut; Srilennawat, Nareerut

2012-05-01

Heat stroke is still an important health problem in Thai army recruits. The authors aimed to evaluate a new method for preventing heat stroke in the newly army recruits during basic training in May-June 2006, by monitoring the bed time body temperature and body weight. One thousand one hundred and fifteen recruits from five army units in Lopburi Province, Thailand were enrolled in the present study. Standardized questionnaire was used for data collection including unit information, personal information, environmental information and daily activity information. Bed time body temperature and body weight were recorded daily. Anyone who had a body temperature > 37.8 degrees C or body weight lossing > 10% in 24 h had to stop training until these indicators were normal. There was no incidence of heat stroke in these army units during this training period. There were 191 recruits who had a body temperature > 37.8 degrees C. The mean duration of the fever was 3.3 +/- 3.3 days. The incidence of fever was 21.4 per 100 persons-month. There were 30 recruits with the body weight lossing > 10%. The duration of body weight loss was one day. Analyzed by mixed model using STATA program, there was statistically significant difference of the body temperature (p < 0.001) but not the body weight (p = 0.644) among the period of time. This monitoring of the bed time body temperature and body weight seems to be effective for the prevention of the occurrence of heat stroke because there was no case of heat stroke in the present study. However, further large-scale study with a control group should be performed.

Overwintering temperature and body condition shift emergence dates of spring-emerging solitary bees.

PubMed

Schenk, Mariela; Mitesser, Oliver; Hovestadt, Thomas; Holzschuh, Andrea

2018-01-01

Solitary bees in seasonal environments must align their life-cycles with favorable environmental conditions and resources; the timing of their emergence is highly fitness relevant. In several bee species, overwintering temperature influences both emergence date and body weight at emergence. High variability in emergence dates among specimens overwintering at the same temperatures suggests that the timing of emergence also depends on individual body conditions. However, possible causes for this variability, such as individual differences in body size or weight, have been rarely studied. In a climate chamber experiment using two spring-emerging mason bees ( Osmia cornuta and O. bicornis ), we investigated the relationship between temperature, emergence date, body weight, and body size, the last of which is not affected by overwintering temperature. Our study showed that body weight declined during hibernation more strongly in warm than in cold overwintering temperatures. Although bees emerged earlier in warm than in cold overwintering temperatures, at the time of emergence, bees in warm overwintering temperatures had lower body weights than bees in cold overwintering temperatures (exception of male O. cornuta ). Among specimens that experienced the same overwintering temperatures, small and light bees emerged later than their larger and heavier conspecifics. Using a simple mechanistic model we demonstrated that spring-emerging solitary bees use a strategic approach and emerge at a date that is most promising for their individual fitness expectations. Our results suggest that warmer overwintering temperatures reduce bee fitness by causing a decrease in body weight at emergence. We showed furthermore that in order to adjust their emergence dates, bees use not only temperature but also their individual body condition as triggers. This may explain differing responses to climate warming within and among bee populations and may have consequences for bee-plant interactions as well as for the persistence of bee populations under climate change.

Daily and estrous rhythmicity of body temperature in domestic cattle

PubMed Central

Piccione, Giuseppe; Caola, Giovanni; Refinetti, Roberto

2003-01-01

Background Rhythmicity in core body temperature has been extensively studied in humans and laboratory animals but much less in farm animals. Extending the study of rhythmicity of body temperature to farm animals is important not only from a comparative perspective but also from an economic perspective, as greater knowledge of this process can lead to improvements in livestock production practices. In this study in cattle, we investigated the maturation of the daily rhythm of body temperature in newborn calves, characterized the parameters of the daily rhythm in young cows, and studied the oscillation in body temperature associated with the estrous cycle in adult cows. Results We found that the daily rhythm of body temperature is absent at birth but matures fully during the first two months of life. The mature rhythm had a mean level of 38.3°C, a range of excursion of 1.4°C, and was more robust than that of any mammalian species previously studied (90% of maximal robustness). Sexually mature cows also exhibited a robust estrous rhythm of body temperature. An elevation of about 1.3°C was observed every 21 days on the day of estrus. Small seasonal variations in this pattern were observed. Conclusion In conclusion, calves exhibit a very robust daily rhythm of body temperature, although this rhythm is absent at birth and develops during the first two months of life. Adult cows exhibit also 21-day rhythmicity in body temperature reflecting the duration of the estrous cycle. PMID:12882649

Efficacy comparison of Korean ginseng and American ginseng on body temperature and metabolic parameters.

PubMed

Park, Eun-Young; Kim, Mi-Hwi; Kim, Eung-Hwi; Lee, Eun-Kyu; Park, In-Sun; Yang, Duck-Choon; Jun, Hee-Sook

2014-01-01

Ginseng has beneficial effects in cancer, diabetes and aging. There are two main varieties of ginseng: Panax ginseng (Korean ginseng) and Panax quinquefolius (American ginseng). There are anecdotal reports that American ginseng helps reduce body temperature, whereas Korean ginseng improves blood circulation and increases body temperature; however, their respective effects on body temperature and metabolic parameters have not been studied. We investigated body temperature and metabolic parameters in mice using a metabolic cage. After administering ginseng extracts acutely (single dose of 1000 mg/kg) or chronically (200 mg/kg/day for four weeks), core body temperature, food intake, oxygen consumption and activity were measured, as well as serum levels of pyrogen-related factors and mRNA expression of metabolic genes. Acute treatment with American ginseng reduced body temperature compared with PBS-treated mice during the night; however, there was no significant effect of ginseng treatment on body temperature after four weeks of treatment. VO 2, VCO 2, food intake, activity and energy expenditure were unchanged after both acute and chronic ginseng treatment compared with PBS treatment. In acutely treated mice, serum thyroxin levels were reduced by red and American ginseng, and the serum prostaglandin E2 level was reduced by American ginseng. In chronically treated mice, red and white ginseng reduced thyroxin levels. We conclude that Korean ginseng does not stimulate metabolism in mice, whereas a high dose of American ginseng may reduce night-time body temperature and pyrogen-related factors.

Assessment of body composition by air-displacement plethysmography: influence of body temperature and moisture.

PubMed

Fields, David A; Higgins, Paul B; Hunter, Gary R

2004-04-01

BACKGROUND: To investigate the effect of body temperature and moisture on body fat (%fat), volume and density by air-displacement plethysmography (BOD POD). METHODS: %fat, body volume and density by the BOD POD before (BOD PODBH) and immediately following hydrostatic weighing (BOD PODFH) were performed in 32 healthy females (age (yr) 33 +/- 11, weight (kg) 64 +/- 14, height (cm) 167 +/- 7). Body temperature and moisture were measured prior to BOD PODBH and prior to BOD PODFH with body moisture defined as the difference in body weight (kg) between the BOD PODBH and BOD PODFH measurements. RESULTS: BOD PODFH %fat (27.1%) and body volume (61.5 L) were significantly lower (P

Non-invasive monitoring of core body temperature rhythms over 72 h in 10 bedridden elderly patients with disorders of consciousness in a Japanese hospital: a pilot study.

PubMed

Matsumoto, Masaru; Sugama, Junko; Okuwa, Mayumi; Dai, Misako; Matsuo, Junko; Sanada, Hiromi

2013-01-01

The purpose of this study was to elucidate the body core temperature rhythms of bedridden elderly patients with disorders of consciousness (DOC) in a Japanese hospital using a simple, non-invasive, deep-body thermometer. We measured body core temperature on the surface of abdomen in 10 bedridden elderly patients with DOC continuously over 72 h. A non-heated core body temperature thermometer was used. The cycle of the body core temperature rhythm was initially derived by using the least squares method. Then, based on that rhythm, the mean, amplitude, and times of day of the highest and lowest body temperatures during the optimum cycle were determined using the cosinor method. We found a 24-h cycle in seven of the 10 patients. One patient had a 6-h, one a 12-h, and one a 63-h cycle. The mean value of the cosine curve in the respective optimum cycles was 36.48 ± 0.34 °C, and the amplitude was 0.22 ± 0.09 °C. Of the seven subjects with 24-h cycles, the highest body temperature occurred between 12:58 and 14:44 h in four. In addition to 24-h cycles of core temperature rhythm, short cycles of 12 and 6-h and a long cycle of 63-h were seen. In order to understand the temperature rhythms of bedridden elderly patients with DOC, it is necessary to monitor their core body temperatures, ideally using a simple, non-invasive device. In the future, it will be important to investigate the relationship of the core temperature rhythm to nursing care and living environment. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Body mass modulates huddling dynamics and body temperature profiles in rabbit pups.

PubMed

Bautista, Amando; Zepeda, José Alfredo; Reyes-Meza, Verónica; Féron, Christophe; Rödel, Heiko G; Hudson, Robyn

2017-10-01

Altricial mammals typically lack the physiological capacity to thermoregulate independently during the early postnatal period, and in litter-bearing species the young benefit strongly from huddling together with their litter siblings. Such litter huddles are highly dynamic systems, often characterized by competition for energetically favorable, central positions. In the present study, carried out in domestic rabbits Oryctolagus cuniculus, we asked whether individual differences in body mass affect changes in body temperature during changes in the position within the huddle. We predicted that pups with relatively lower body mass should be more affected by such changes arising from huddle dynamics in comparison to heavier ones. Changes in pups' maximum body surface temperature (determined by infrared thermography) were significantly affected by changes in the number of their neighbors in the litter huddle, and indeed these temperature changes largely depended on the pups' body mass relative to their litter siblings. Lighter pups showed significant increases in their maximum body surface temperature when their number of huddling partners increased by one or two siblings whereas pups with intermediate or heavier body mass did not show such significant increases in maximum body temperature when experiencing such changes. A similar pattern was found with respect to average body surface temperature. This strong link between changes in the number of huddling partners and body surface temperature in lighter pups might, on the one hand, arise from a higher vulnerability of such pups due to their less favorable body surface area-to-volume ratio. On the other hand, as lighter pups generally had fewer neighbors than heavier ones and thus typically a comparatively smaller body surface in contact with siblings, they potentially had more to gain from increasing their number of neighbors. The present findings might help to understand how individual differences in body mass within a litter lead to the emergence of individual differences in sibling interactions during early postnatal life in different species of altricial and litter-bearing mammals. Copyright © 2017 Elsevier Inc. All rights reserved.

First investigations to refine video-based IR thermography as a non-invasive tool to monitor the body temperature of calves.

PubMed

Hoffmann, G; Schmidt, M; Ammon, C

2016-09-01

In this study, a video-based infrared camera (IRC) was investigated as a tool to monitor the body temperature of calves. Body surface temperatures were measured contactless using videos from an IRC fixed at a certain location in the calf feeder. The body surface temperatures were analysed retrospectively at three larger areas: the head area (in front of the forehead), the body area (behind forehead) and the area of the entire animal. The rectal temperature served as a reference temperature and was measured with a digital thermometer at the corresponding time point. A total of nine calves (Holstein-Friesians, 8 to 35 weeks old) were examined. The average maximum temperatures of the area of the entire animal (mean±SD: 37.66±0.90°C) and the head area (37.64±0.86°C) were always higher than that of the body area (36.75±1.06°C). The temperatures of the head area and of the entire animal were very similar. However, the maximum temperatures as measured using IRC increased with an increase in calf rectal temperature. The maximum temperatures of each video picture for the entire visible body area of the calves appeared to be sufficient to measure the superficial body temperature. The advantage of the video-based IRC over conventional IR single-picture cameras is that more than one picture per animal can be analysed in a short period of time. This technique provides more data for analysis. Thus, this system shows potential as an indicator for continuous temperature measurements in calves.

Thermal regulation in Macaca mulatta during space flight

NASA Technical Reports Server (NTRS)

Klimovitsky, V. Y.; Alpatov, A. M.; Hoban-Higgins, T. M.; Utekhina, E. S.; Fuller, C. A.

2000-01-01

The results of studies of body temperature and thermal regulation in Macaca mulatta flown on biosatellites Bion 6-11 are presented. The effect of microgravity on deep body temperature as compared to skin temperature was investigated. In most animals, deep body temperature declined moderately and then tended to return to normal. Brain temperature/ankle temperature correlation changed. The system of thermal regulation was found to function adequately in space.

Profound and Rapid Reduction in Body Temperature Induced by the Melanocortin Receptor Agonists

PubMed Central

Xu, Yuanzhong; Kim, Eun Ran; Fan, Shengjie; Xia, Yan; Xu, Yong; Huang, Cheng; Tong, Qingchun

2014-01-01

The melanocortin receptor 4 (MC4R) plays a major role in body weight regulation and its agonist MTII has been widely used to study the role of MC4Rs in energy expenditure promotion and feeding reduction. Unexpectedly, we observed that intraperitoneal (i.p.) administration of MTII induced a rapid reduction in both body temperature and energy expenditure, which was independent of its effect on feeding and followed by a prolonged increase in energy expenditure. The rapid reduction was at least partly mediated by brain neurons since intracerebroventricular (icv) administration of alpha melanocyte-stimulating hormone, an endogenous melanocortin receptor agonist, produced a similar response. In addition, the body temperature-lowering effect of MTII was independent of the presence of MC4Rs, but in a similar fashion to the previously shown effect on body temperature by 5′AMP. Moreover, β-adrenergic receptors (β-ARs) were required for the recovery from low body temperature induced by MTII and further pharmacological studies showed that the MTII’s effect on body temperature may be partially mediated by the vasopressin V1a receptors. Collectively, our results reveal a previously unappreciated role for the melanocortin pathway in rapidly lowering body temperature. PMID:25065745

Elevated body temperature is linked to fatigue in an Italian sample of relapsing-remitting multiple sclerosis patients.

PubMed

Leavitt, V M; De Meo, E; Riccitelli, G; Rocca, M A; Comi, G; Filippi, M; Sumowski, J F

2015-11-01

Elevated body temperature was recently reported for the first time in patients with relapsing-remitting multiple sclerosis (RRMS) relative to healthy controls. In addition, warmer body temperature was associated with worse fatigue. These findings are highly novel, may indicate a novel pathophysiology for MS fatigue, and therefore warrant replication in a geographically separate sample. Here, we investigated body temperature and its association to fatigue in an Italian sample of 44 RRMS patients and 44 age- and sex-matched healthy controls. Consistent with our original report, we found elevated body temperature in the RRMS sample compared to healthy controls. Warmer body temperature was associated with worse fatigue, thereby supporting the notion of endogenous temperature elevations in patients with RRMS as a novel pathophysiological factor underlying fatigue. Our findings highlight a paradigm shift in our understanding of the effect of heat in RRMS, from exogenous (i.e., Uhthoff's phenomenon) to endogenous. Although randomized controlled trials of cooling treatments (i.e., aspirin, cooling garments) to reduce fatigue in RRMS have been successful, consideration of endogenously elevated body temperature as the underlying target will enhance our development of novel treatments.

Variation in the thermal parameters of Odontophrynus occidentalis in the Monte desert, Argentina: response to the environmental constraints.

PubMed

Sanabria, Eduardo Alfredo; Quiroga, Lorena Beatriz; Martino, Adolfo Ludovico

2012-03-01

We studied the variation of thermal parameters of Odontophrynus occidentalis between season (wet and dry) in the Monte desert (Argentina). We measured body temperatures, microhabitat temperatures, and operative temperatures; while in the laboratory, we measured the selected body temperatures. Our results show a change in the thermal parameters of O. occidentalis that is related to environmental constraints of their thermal niche. Environmental thermal constraints are present in both seasons (dry and wet), showing variations in thermal parameters studied. Apparently imposed environmental restrictions, the toads in nature always show body temperatures below the set point. Acclimatization is an advantage for toads because it allows them to bring more frequent body temperatures to the set point. The selected body temperature has seasonal intraindividual variability. These variations can be due to thermo-sensitivity of toads and life histories of individuals that limits their allocation and acquisition of resources. Possibly the range of variation found in selected body temperature is a consequence of the thermal environmental variation along the year. These variations of thermal parameters are commonly found in deserts and thermal bodies of nocturnal ectotherms. The plasticity of selected body temperature allows O. occidentales to have longer periods of activity for foraging and reproduction, while maintaining reasonable high performance at different temperatures. The plasticity in seasonal variation of the thermal parameters has been poorly studied, and is greatly advantageous to desert species during changes in both seasonal and daily temperature, as these environments are known for their high environmental variability. © 2012 WILEY PERIODICALS, INC.

Comparison of three methods of temperature measurement in hypothermic, euthermic, and hyperthermic dogs.

PubMed

Greer, Rebecca J; Cohn, Leah A; Dodam, John R; Wagner-Mann, Colette C; Mann, F A

2007-06-15

To assess the reliability and accuracy of a predictive rectal thermometer, an infrared auricular thermometer designed for veterinary use, and a subcutaneous temperature-sensing microchip for measurement of core body temperature over various temperature conditions in dogs. Prospective study. 8 purpose-bred dogs. A minimum of 7 days prior to study commencement, a subcutaneous temperature-sensing microchip was implanted in 1 of 3 locations (interscapular, lateral aspect of shoulder, or sacral region) in each dog. For comparison with temperatures measured via rectal thermometer, infrared auricular thermometer, and microchip, core body temperature was measured via a thermistor-tipped pulmonary artery (TTPA) catheter. Hypothermia was induced during anesthesia at the time of TTPA catheter placement; on 3 occasions after placement of the catheter, hyperthermia was induced via administration of a low dose of endotoxin. Near-simultaneous duplicate temperature measurements were recorded from the TTPA catheter, the rectal thermometer, auricular thermometer, and subcutaneous microchips during hypothermia, euthermia, and hyperthermia. Reliability (variability) of temperature measurement for each device and agreement between each device measurement and core body temperature were assessed. Variability between duplicate near-simultaneous temperature measurements was greatest for the auricular thermometer and least for the TTPA catheter. Measurements obtained by use of the rectal thermometer were in closest agreement with core body temperature; for all other devices, temperature readings typically underestimated core body temperature. Among the 3 methods of temperature measurement, rectal thermometry provided the most accurate estimation of core body temperature in dogs.

Control of body temperature and immune function in patients undergoing open surgery for gastric cancer.

PubMed

Shao, Li; Pang, Nannan; Yan, Ping; Jia, Fengju; Sun, Qi; Ma, Wenjuan; Yang, Yi

2018-04-09

The influence of mild perioperative hypothermia on the immune function and incidence of postoperative wound infections has been suggested, but the specific mechanism is unclear. This study aimed to analyze the body temperature, immune function, and wound infection rates in patients receiving open surgery for gastric cancer. Body temperature was controlled in each patient using one of four different methods: wrapping limbs, head and neck; insulated blankets; warming infusion fluids and insulated blankets; and warming fluids without insulated blankets. One hundred patients were randomly divided into four groups of 25 patients each, and every group received a different intraoperative treatment for maintaining normal body temperature. Nasopharyngeal and rectal temperatures, transforming growth factor beta (TGF-β), interleukin 10 (IL-10) levels, and cluster of differentiation (CD)3+ and CD4+/CD25+ regulatory T cell (Treg) counts were measured before surgery and at 2 and 4 hours postoperatively. Patients were evaluated at one week after surgery for signs of infection. Intraoperative body temperature and measures of immune function varied significantly between the four groups, with the largest temperature changes observed in the group in which only the limbs were wrapped in cotton pads to control the body temperature. The group in which infusion fluids and transfused blood (if needed) were heated to 37℃, peritoneal irrigation fluid was heated to 37℃, and an insulation blanket was heated to 39℃ and placed under the patient, showed the lowest temperature change (i.e., close to normal temperature) and cytokine response after surgery. No intergroup differences were found in the infection rates at one week after surgery. In conclusion, body temperature variation during surgery affects the immune function of patients, and maintaining body temperature close to normal results in the least variation of immune function.

POMC neurons in heat: A link between warm temperatures and appetite suppression.

PubMed

Vicent, Maria A; Mook, Conor L; Carter, Matthew E

2018-05-01

When core body temperature increases, appetite and food consumption decline. A higher core body temperature can occur during exercise, during exposure to warm environmental temperatures, or during a fever, yet the mechanisms that link relatively warm temperatures to appetite suppression are unknown. A recent study in PLOS Biology demonstrates that neurons in the mouse hypothalamus that express pro-opiomelanocortin (POMC), a neural population well known to suppress food intake, also express a temperature-sensitive ion channel, transient receptor potential vanilloid 1 (TRPV1). Slight increases in body temperature cause a TRPV1-dependent increase in activity in POMC neurons, which suppresses feeding in mice. Taken together, this study suggests a novel mechanism linking body temperature and food-seeking behavior.

An application of randomization for detecting evidence of thermoregulation in timber rattlesnakes (Crotalus horridus) from northwest Arkansas.

PubMed

Wills, C A; Beaupre, S J

2000-01-01

Most reptiles maintain their body temperatures within normal functional ranges through behavioral thermoregulation. Under some circumstances, thermoregulation may be a time-consuming activity, and thermoregulatory needs may impose significant constraints on the activities of ectotherms. A necessary (but not sufficient) condition for demonstrating thermoregulation is a difference between observed body temperature distributions and available operative temperature distributions. We examined operative and body temperature distributions of the timber rattlesnake (Crotalus horridus) for evidence of thermoregulation. Specifically, we compared the distribution of available operative temperatures in the environment to snake body temperatures during August and September. Operative temperatures were measured using 48 physical models that were randomly deployed in the environment and connected to a Campbell CR-21X data logger. Body temperatures (n=1,803) were recorded from 12 radiotagged snakes using temperature-sensitive telemetry. Separate randomization tests were conducted for each hour of day within each month. Actual body temperature distributions differed significantly from operative temperature distributions at most time points considered. Thus, C. horridus exhibits a necessary (but not sufficient) condition for demonstrating thermoregulation. However, unlike some desert ectotherms, we found no compelling evidence for thermal constraints on surface activity. Randomization may prove to be a powerful technique for drawing inferences about thermoregulation without reliance on studies of laboratory thermal preference.

Paclitaxel-induced hypothermia and hypoperfusion increase breast cancer metastasis and angiogenesis in mice

PubMed Central

Ami, Nozomi; Sato, Hideki; Hayakawa, Yoshihiro

2018-01-01

Housing temperature has been shown to influence thermoregulation and behavior of preclinical cancer models; and anti-cancer drugs typically reduce peripheral blood flow and body temperature. In the present study, the effects of paclitaxel (PTX)-induced reduction of body temperature and peripheral blood flow on metastatic 4T1 breast cancer was investigated in a mouse model and the modification of these effects by thermoneutral temperature was also assessed. A single dose of PTX decreased the body temperature and peripheral blood flow in mice housed at a standard temperature (23°C). Furthermore, although lung metastasis and angiogenesis of inoculated 4T1 cells increased in mice pretreated with PTX, mice housed at a thermoneutral temperature (30°C) could compensate their body temperature and peripheral blood flow compared with control mice, and also suppressed 4T1 angiogenesis and metastasis to lung. The present results imply that maintenance of body temperature or efficient energy supply for thermogenesis may prevent tumor relapse or metastasis after chemotherapy. PMID:29434941

Within-subject correlations between evening-related changes in body temperature and melatonin in the spinal cord injured.

PubMed

Jones, Helen; Eijsvogels, Thijs M H; Nyakayiru, Jean; Verheggen, Rebecca J H M; Thompson, Andrew; Groothuis, Jan T; Atkinson, Greg; Hopman, Maria T E; Thijssen, Dick H J

2014-03-01

Individuals with a spinal cord injury (SCI) demonstrate altered circadian variation in thermoregulatory control. Recently, we reported that tetraplegia is associated with a blunted release of melatonin in the evening. In order to examine whether this finding relates to circadian thermoregulation, we compared the correlations between evening changes in melatonin, core and skin temperature between thoracic and cervical SCI and able-bodied participants. In 10 able-bodied, 9 paraplegic and 8 tetraplegic participants, we measured, between 1900 and 2300 h, core temperature, proximal skin temperature (above and below the level of the lesion) and physical activity. Salivary melatonin was also sampled during this period and analyzed using enzyme linked immunosorbant assay. Between 1900 and 2300 h, core and upper limb skin temperature gradually decreased in all groups (p = 0.01). A significant group × time interaction was evident in lower body skin temperature (p = 0.03). Lower body skin temperature was significantly higher in able-bodied controls compared with tetraplegics between 1900 and 2000 h (p < 0.05). In able-bodied and paraplegic participants, the changes in melatonin and core temperature were inversely correlated (r = -0.44 and -0.54, respectively, both p = 0.01). Melatonin and mean skin temperature changes were also inversely correlated (able-bodied controls: r = -0.24; p = 0.05 and paraplegics: r = -0.30; p= 0.02). The inverse correlation between evening changes in melatonin and thermoregulation is of a similar magnitude in paraplegic and able-bodied controls. In contrast, changes in skin temperature, below the level of the lesion, are unrelated to changes in melatonin in tetraplegics.

Is higher body temperature beneficial in ischemic stroke patients with normal admission CT angiography of the cerebral arteries?

PubMed

Kvistad, Christopher Elnan; Khanevski, Andrej; Nacu, Aliona; Thomassen, Lars; Waje-Andreassen, Ulrike; Naess, Halvor

2014-01-01

Low body temperature is considered beneficial in ischemic stroke due to neuroprotective mechanisms, yet some studies suggest that higher temperatures may improve clot lysis and outcomes in stroke patients treated with tissue plasminogen activator (tPA). The effect of increased body temperature in stroke patients treated with tPA and with normal computed tomography angiography (CTA) on admission is unknown. We hypothesized a beneficial effect of higher body temperature in the absence of visible clots on CTA, possibly due to enhanced lysis of small, peripheral clots. Patients with ischemic stroke admitted to our Stroke Unit between February 2006 and April 2013 were prospectively registered in a database (Bergen NORSTROKE Registry). Ischemic stroke patients treated with tPA with normal CTA of the cerebral arteries were included. Outcomes were assessed by the modified Rankin Scale (mRS) after 1 week. An excellent outcome was defined as mRS=0, and a favorable outcome as mRS=0-1. A total of 172 patients were included, of which 48 (27.9%) had an admission body temperature ≥37.0°C, and 124 (72.1%) had a body temperature <37.0°C. Body temperature ≥37.0°C was independently associated with excellent outcomes (odds ratio [OR]: 2.8; 95% confidence interval [CI]: 1.24-6.46; P=0.014) and favorable outcomes (OR: 2.8; 95% CI: 1.13-4.98; P=0.015) when adjusted for confounders. We found an association between higher admission body temperature and improved outcome in tPA-treated stroke patients with normal admission CTA of the cerebral arteries. This may suggest a beneficial effect of higher body temperature on clot lysis in the absence of visible clots on CTA.

Temporal profile of body temperature in acute ischemic stroke: relation to infarct size and outcome.

PubMed

Geurts, Marjolein; Scheijmans, Féline E V; van Seeters, Tom; Biessels, Geert J; Kappelle, L Jaap; Velthuis, Birgitta K; van der Worp, H Bart

2016-11-21

High body temperatures after ischemic stroke have been associated with larger infarct size, but the temporal profile of this relation is unknown. We assess the relation between temporal profile of body temperature and infarct size and functional outcome in patients with acute ischemic stroke. In 419 patients with acute ischemic stroke we assessed the relation between body temperature on admission and during the first 3 days with both infarct size and functional outcome. Infarct size was measured in milliliters on CT or MRI after 3 days. Poor functional outcome was defined as a modified Rankin Scale score ≥3 at 3 months. Body temperature on admission was not associated with infarct size or poor outcome in adjusted analyses. By contrast, each additional 1.0 °C in body temperature on day 1 was associated with 0.31 ml larger infarct size (95% confidence interval (CI) 0.04-0.59), on day 2 with 1.13 ml larger infarct size(95% CI, 0.83-1.43), and on day 3 with 0.80 ml larger infarct size (95% CI, 0.48-1.12), in adjusted linear regression analyses. Higher peak body temperatures on days two and three were also associated with poor outcome (adjusted relative risks per additional 1.0 °C in body temperature, 1.52 (95% CI, 1.17-1.99) and 1.47 (95% CI, 1.22-1.77), respectively). Higher peak body temperatures during the first days after ischemic stroke, rather than on admission, are associated with larger infarct size and poor functional outcome. This suggests that prevention of high temperatures may improve outcome if continued for at least 3 days.

A mechanistic model to study the thermal ecology of a southeastern pacific dominant intertidal mussel and implications for climate change.

PubMed

Finke, G R; Bozinovic, F; Navarrete, S A

2009-01-01

Developing mechanistic models to predict an organism's body temperature facilitates the study of physiological stresses caused by extreme climatic conditions the species might have faced in the past or making predictions about changes to come in the near future. Because the models combine empirical observation of different climatic variables with essential morphological attributes of the species, it is possible to examine specific aspects of predicted climatic changes. Here, we develop a model for the competitively dominant intertidal mussel Perumytilus purpuratus that estimates body temperature on the basis of meteorological and tidal data with an average difference (+/-SE) of 0.410 degrees +/- 0.0315 degrees C in comparison with a field-deployed temperature logger. Modeled body temperatures of P. purpuratus in central Chile regularly exceeded 30 degrees C in summer months, and values as high as 38 degrees C were found. These results suggest that the temperatures reached by mussels in the intertidal zone in central Chile are not sufficiently high to induce significant mortality on adults of this species; however, because body temperatures >40 degrees C can be lethal for this species, sublethal effects on physiological performance warrant further investigation. Body temperatures of mussels increased sigmoidally with increasing tidal height. Body temperatures of individuals from approximately 70% of the tidal range leveled off and did not increase any further with increasing tidal height. Finally, body size played an important role in determining body temperature. A hypothetical 5-cm-long mussel (only 1 cm longer than mussels found in nature) did reach potentially lethal body temperatures, suggesting that the biophysical environment may play a role in limiting the size of this small species.

Assessment of body composition by air-displacement plethysmography: influence of body temperature and moisture

PubMed Central

Fields, David A; Higgins, Paul B; Hunter, Gary R

2004-01-01

Background To investigate the effect of body temperature and moisture on body fat (%fat), volume and density by air-displacement plethysmography (BOD POD). Methods %fat, body volume and density by the BOD POD before (BOD PODBH) and immediately following hydrostatic weighing (BOD PODFH) were performed in 32 healthy females (age (yr) 33 ± 11, weight (kg) 64 ± 14, height (cm) 167 ± 7). Body temperature and moisture were measured prior to BOD PODBH and prior to BOD PODFH with body moisture defined as the difference in body weight (kg) between the BOD PODBH and BOD PODFH measurements. Results BOD PODFH %fat (27.1%) and body volume (61.5 L) were significantly lower (P ≤ 0.001) and body density (1.0379 g/cm3) significantly higher (P ≤ 0.001) than BOD PODBH %fat (28.9%), body volume (61.7 L), and body density (1.0341 g/cm3). A significant increase in body temperature (~0.6°C; P ≤ 0.001) and body moisture (0.08 kg; P ≤ 0.01) were observed between BOD PODBH and BOD PODFH. Body surface area was positively associated with the difference in %fat independent of changes in body temperature and moisture, r = 0.30, P < 0.05. Conclusion These data demonstrate for the first time that increases in body heat and moisture result in an underestimation of body fat when using the BOD POD, however, the precise mechanism remains unidentified. PMID:15059287

Portable Body Temperature Conditioner

DTIC Science & Technology

2012-10-01

TITLE: Portable Body Temperature Conditioner PRINCIPAL INVESTIGATOR...Body Temperature Conditioner 5b. GRANT NUMBER W81XWH-11-1-0792 5c... Conditioner Principal Investigator: Timothy D. Browder, MD Co-Investigator: Deborah Kuhls, MD Co-Investigator: John Fildes, MD Table of Contents

Economic thermoregulatory response explains mismatch between thermal physiology and behaviour in newts.

PubMed

Gvoždík, Lumír; Kristín, Peter

2017-03-15

Temperature is an important factor determining distribution and abundance of organisms. Predicting the impact of warming climate on ectotherm populations requires information about species' thermal requirements, i.e. their so-called 'thermal niche'. The characterization of thermal niche remains a complicated task. We compared the applicability of two indirect approaches, based on reaction norm (aerobic scope curve) and optimality (preferred body temperature) concepts, for indirect estimation of thermal niche while using newts, Ichthyosaura alpestris , as a study system. If the two approaches are linked, then digesting newts should keep their body temperatures close to values maximizing aerobic scope for digestion. After feeding, newts maintained their body temperatures within a narrower range than did hungry individuals. The range of preferred body temperatures was well below the temperature maximizing aerobic scope for digestion. Optimal temperatures for factorial aerobic scope fell within the preferred body temperature range of digesting individuals. We conclude that digesting newts prefer body temperatures that are optimal for the maximum aerobic performance but relative to the maintenance costs. What might be termed the 'economic' thermoregulatory response explains the mismatch between thermal physiology and behaviour in this system. © 2017. Published by The Company of Biologists Ltd.

Distribution of skin temperature in Mexican children.

PubMed

Kolosovas-Machuca, Eleazar Samuel; González, Francisco Javier

2011-08-01

Infrared thermography can be a valuable diagnostic tool in the evaluation and management of several pathologies; however, the temperature pattern of the healthy body should be known in order to perform a more precise clinical evaluation. A total of 25 healthy children (10 female and 15 male) were examined with a thermographic camera. Eighty-four temperature points of the body were recorded, saved in a database, and analyzed. The measurements showed that the forehead, neck, and the cervical area have the highest average temperatures of the whole body, and that the temperature distribution between boys and girls is very similar. The difference in skin temperature along the y-axis of the body varied up to 5.1°C; however, the average difference in skin temperature along the x-axis of the body was 0.7°C. These temperature variations observed in children are lower than the ones reported for adults, which could be due to a greater variation of body fat distribution in adults. This study shows that thermography could be a good tool for disease diagnosis in children as there is a lower skin temperature variation among children than among adults. © 2011 John Wiley & Sons A/S.

Effect of short-term decrease in water temperature on body temperature and involvement of testosterone in steelhead and rainbow trout, Oncorhynchus mykiss.

PubMed

Miura, Go; Munakata, Arimune; Yada, Takashi; Schreck, Carl B; Noakes, David L G; Matsuda, Hiroyuki

2013-09-01

The Pacific salmonid species Oncorhynchus mykiss is separated into a migratory form (steelhead trout) and a non-migratory form (rainbow trout). A decrease in water temperature is likely a cue triggering downstream behavior in the migratory form, and testosterone inhibits onset of this behavior. To elucidate differences in sensitivity to water temperature decreases between the migratory and non-migratory forms and effect of testosterone on the sensitivity, we examined two experiments. In experiment 1, we compared changes in body temperature during a short-term decrease in water temperature between both live and dead steelhead and rainbow trout. In experiment 2, we investigated effects of testosterone on body temperature decrease in steelhead trout. Water temperature was decreased by 3°C in 30min. The body temperature of the steelhead decreased faster than that of the rainbow trout. In contrast, there was no significant difference in the decrease in body temperature between dead steelhead and rainbow trout specimens. The body temperature of the testosterone-treated steelhead trout decreased more slowly than that of control fish. Our results suggest that the migratory form is more sensitive to decreases in water temperature than the non-migratory form. Moreover, testosterone might play an inhibitory role in sensitivity to such decreases. Copyright © 2013 Elsevier Inc. All rights reserved.

The costs of keeping cool in a warming world: implications of high temperatures for foraging, thermoregulation and body condition of an arid-zone bird.

PubMed

du Plessis, Katherine L; Martin, Rowan O; Hockey, Philip A R; Cunningham, Susan J; Ridley, Amanda R

2012-10-01

Recent mass mortalities of bats, birds and even humans highlight the substantial threats that rising global temperatures pose for endotherms. Although less dramatic, sublethal fitness costs of high temperatures may be considerable and result in changing population demographics. Endothermic animals exposed to high environmental temperatures can adjust their behaviour (e.g. reducing activity) or physiology (e.g. elevating rates of evaporative water loss) to maintain body temperatures within tolerable limits. The fitness consequences of these adjustments, in terms of the ability to balance water and energy budgets and therefore maintain body condition, are poorly known. We investigated the effects of daily maximum temperature on foraging and thermoregulatory behaviour as well as maintenance of body condition in a wild, habituated population of Southern Pied Babblers Turdoides bicolor. These birds inhabit a hot, arid area of southern Africa where they commonly experience environmental temperatures exceeding optimal body temperatures. Repeated measurements of individual behaviour and body mass were taken across days varying in maximum air temperature. Contrary to expectations, foraging effort was unaffected by daily maximum temperature. Foraging efficiency, however, was lower on hotter days and this was reflected in a drop in body mass on hotter days. When maximum air temperatures exceeded 35.5 °C, individuals no longer gained sufficient weight to counter typical overnight weight loss. This reduction in foraging efficiency is likely driven, in part, by a trade-off with the need to engage in heat-dissipation behaviours. When we controlled for temperature, individuals that actively dissipated heat while continuing to forage experienced a dramatic decrease in their foraging efficiency. This study demonstrates the value of investigations of temperature-dependent behaviour in the context of impacts on body condition, and suggests that increasingly high temperatures will have negative implications for the fitness of these arid-zone birds. © 2012 Blackwell Publishing Ltd.

Thermoregulatory challenges in the habitat of the world's smallest tortoise, Chersobius signatus.

PubMed

Loehr, Victor J T

2018-01-01

Ectotherms have various means of dealing with low environmental temperatures, but relatively few species have been rigorously investigated. Consequently, we have little information to predict how ectotherm populations might respond to global temperature changes. Tortoises from temperate and subtropical regions often overcome periodically cool conditions by hibernation, but speckled dwarf tortoises (Chersobius signatus) need to remain active to exploit ephemeral resources in their arid winter-rainfall habitat. This study investigated how dwarf tortoises cope with low temperatures in winter and spring, by measuring thermal habitat quality and thermoregulation based on differently-sized operative temperature models in sun, shade, and in deep crevices. Investigations continued in summer and autumn to obtain a year-round picture of thermoregulatory challenges. Although large models (i.e., larger than dwarf tortoises) were expected to have lower operative temperatures than smaller models, due to the former's larger thermal inertia, all model sizes had similar temperatures. Hence, the species' small body size does not appear constrained by obtainable body temperatures in cool seasons. Nevertheless, low operative temperatures in winter posed a challenge for the tortoises, which reached their field-preferred body temperature for an average of only 0.8-0.9h per day. Moreover, a low thermoregulation effectiveness suggested that tortoises traded-off physiological benefits of favourable body temperatures against predation risk. Spring and autumn provided higher temperatures, but summer caused the greatest thermoregulatory challenge. Although summer body temperatures were closer to field-preferred body temperature than in any other season, tortoises required rock crevices to avoid overheating. The small size of dwarf tortoises might help them utilise crevices. In summer, maximum operative temperatures in crevices were similar to field-preferred body temperature, indicating that an increase in environmental temperatures might be detrimental to dwarf tortoises. In light of projected temperature rises, future studies should assess if dwarf tortoises can cope with higher environmental temperatures in summer. Copyright © 2017 Elsevier Ltd. All rights reserved.

Body Temperature Cycles Control Rhythmic Alternative Splicing in Mammals.

PubMed

Preußner, Marco; Goldammer, Gesine; Neumann, Alexander; Haltenhof, Tom; Rautenstrauch, Pia; Müller-McNicoll, Michaela; Heyd, Florian

2017-08-03

The core body temperature of all mammals oscillates with the time of the day. However, direct molecular consequences of small, physiological changes in body temperature remain largely elusive. Here we show that body temperature cycles drive rhythmic SR protein phosphorylation to control an alternative splicing (AS) program. A temperature change of 1°C is sufficient to induce a concerted splicing switch in a large group of functionally related genes, rendering this splicing-based thermometer much more sensitive than previously described temperature-sensing mechanisms. AS of two exons in the 5' UTR of the TATA-box binding protein (Tbp) highlights the general impact of this mechanism, as it results in rhythmic TBP protein levels with implications for global gene expression in vivo. Together our data establish body temperature-driven AS as a core clock-independent oscillator in mammalian peripheral clocks. Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of meal size, meal type, and body temperature on the specific dynamic action of anurans.

PubMed

Secor, Stephen M; Wooten, Jessica A; Cox, Christian L

2007-02-01

Specific dynamic action (SDA), the increase in metabolism stemming from meal digestion and assimilation, varies as a function of meal size, meal type, and body temperature. To test predictions of these three determinants of SDA, we quantified and compared the SDA responses of nine species of anurans, Bombina orientalis, Bufo cognatus, Ceratophrys ornata, Dyscophus antongilli, Hyla cinerea, Kassina maculata, Kassina senegalensis, Pyxicephalus adspersus, and Rana catesbeiana subjected to meal size, meal type, and body temperature treatments. Over a three to seven-fold increase in meal size, anurans experienced predicted increases in postprandial rates of oxygen consumption (VO(2)) the duration of elevated VO(2) and SDA. Meal type had a significant influence on the SDA response, as the digestion and assimilation of hard-bodied, chitinous crickets, mealworms, and superworms required 76% more energy than the digestion and assimilation of soft-bodied earthworms, waxworms, and neonate rodents. Body temperature largely effected the shape of the postprandial metabolic profile; peak VO(2) increased and the duration of the response decreased with an increase in body temperature. Variation in body temperature did not significantly alter SDA for four species, whereas both H. cinerea and R. catesbeiana experienced significant increases in SDA with body temperature. For 13 or 15 species of anurans ranging in mass from 2.4 to 270 g, SMR, postprandial peak VO(2) and SDA scaled with body mass (log-log) with mass exponents of 0.79, 0.93, and 1.05, respectively.

Profound and rapid reduction in body temperature induced by the melanocortin receptor agonists.

PubMed

Xu, Yuanzhong; Kim, Eun Ran; Fan, Shengjie; Xia, Yan; Xu, Yong; Huang, Cheng; Tong, Qingchun

2014-08-22

The melanocortin receptor 4 (MC4R) plays a major role in body weight regulation and its agonist MTII has been widely used to study the role of MC4Rs in energy expenditure promotion and feeding reduction. Unexpectedly, we observed that intraperitoneal (i.p.) administration of MTII induced a rapid reduction in both body temperature and energy expenditure, which was independent of its effect on feeding and followed by a prolonged increase in energy expenditure. The rapid reduction was at least partly mediated by brain neurons since intracerebroventricular (icv) administration of alpha melanocyte-stimulating hormone, an endogenous melanocortin receptor agonist, produced a similar response. In addition, the body temperature-lowering effect of MTII was independent of the presence of MC4Rs, but in a similar fashion to the previously shown effect on body temperature by 5'AMP. Moreover, β-adrenergic receptors (β-ARs) were required for the recovery from low body temperature induced by MTII and further pharmacological studies showed that the MTII's effect on body temperature may be partially mediated by the vasopressin V1a receptors. Collectively, our results reveal a previously unappreciated role for the melanocortin pathway in rapidly lowering body temperature. Copyright © 2014 Elsevier Inc. All rights reserved.

Differences in oral temperature and body shape in two populations with different propensities for obesity.

PubMed

Vozarova, B; Weyer, C; Bogardus, C; Ravussin, E; Tataranni, P A

2002-06-01

Body temperature is a function of heat production and heat dissipation. Substantial interindividual variability has been reported in healthy humans. We hypothesized that Pima Indians, a population with a high prevalence of abdominal obesity, may have a lower surface area relative to volume, that is, lower radiating area, and therefore a higher body temperature compared to Caucasians. Body composition, including volume (hydrodensitometry), and oral temperature were assessed in 69 nondiabetic Caucasian [age, 30 +/- 7 years; body fat, 21 +/- 8% (mean +/- SD)] and 115 Pima Indian males [age, 27 +/- 6 years; body fat, 28 +/- 6%]. Surface area was estimated from height, weight, and waist circumference (Bouchard's equation). In 47 Pima Indians, measures of insulin sensitivity (M, hyperinsulinemic euglycemic clamp) were available. Compared to Caucasians, Pima Indians had a higher oral temperature [36.4 +/- 0.3 degrees C vs. 36.3 +/- 0.3 degrees C (mean +/- SD), p < 0.04] and lower surface area relative to volume (2.19 +/- 0.05 vs. 2.23 +/- 0.26 m(2), p < 0.0001). Surface area relative to volume was negatively correlated with oral temperature (r = -0.14, p < 0.05), but in a multiple linear regression model it did not entirely explain the ethnic difference in oral temperature. Oral temperature was inversely correlated with M (r = -0.28, p < 0.05). Conclusions-Pima Indians have higher oral temperature and lower surface area relative to volume than Caucasians. The ethnic difference in temperature does not seem to be entirely explained by differences in body composition and body shape. Interestingly, higher oral temperature was associated with insulin resistance, a risk factor for type 2 diabetes.

Temperature Control of Hypertensive Rats during Moderate Exercise in Warm Environment.

PubMed

Campos, Helton O; Leite, Laura H R; Drummond, Lucas R; Cunha, Daise N Q; Coimbra, Cândido C; Natali, Antônio J; Prímola-Gomes, Thales N

2014-09-01

The control of body temperature in Spontaneously Hypertensive Rat (SHR) subjected to exercise in warm environment was investigated. Male SHR and Wistar rats were submitted to moderate exercise in temperate (25°C) and warm (32°C) environments while body and tail skin temperatures, as well as oxygen consumption, were registered. Total time of exercise, workload performed, mechanical efficiency and heat storage were determined. SHR had increased heat production and body temperature at the end of exercise, reduced mechanical efficiency and increased heat storage (p < 0.05). Furthermore, these rats also showed a more intense and faster increase in body temperature during moderate exercise in the warm environment (p < 0.05). The lower mechanical efficiency seen in SHR was closely correlated with their higher body temperature at the point of fatigue in warm environment (p < 0.05). Our results indicate that SHR exhibit significant differences in body temperature control during moderate exercise in warm environment characterized by increased heat production and heat storage during moderate exercise in warm environment. The combination of these responses result in aggravated hyperthermia linked with lower mechanical efficiency. Key PointsThe practice of physical exercise in warm environment has gained importance in recent decades mainly because of the progressive increases in environmental temperature;To the best of our knowledge, these is the first study to analyze body temperature control of SHR during moderate exercise in warm environment;SHR showed increased heat production and heat storage that resulted in higher body temperature at the end of exercise;SHR showed reduced mechanical efficiency;These results demonstrate that when exercising in a warm environment the hypertensive rat exhibit differences in temperature control.

Control of liquid cooling garments: technical control of body heat storage.

PubMed

Hexamer, M; Werner, J

1996-07-01

This paper describes a concept of how liquid cooling garments (LCG) can be automatically controlled by the objective physiological state. The technically controlled parameter was mean body temperature which was calculated from the measured rectal and mean skin temperature. This was motivated by the fact that mean body temperature is the basis for estimating body heat storage, a commonly used measure of thermal strain. Here the setpoint of mean body temperature was the individual value taken in a preceeding resting period and it was the task of the technical controller to keep the actual value of mean body temperature as close as possible to the setpoint. The most important tuning parameters of the controller were the weighting coefficients for rectal and mean skin temperature in the calculation for mean body temperature. The ratio of these two coefficients determined the degree of compensation for any rectal temperature shift by changing mean skin temperature. Test experiments were carried out (n = 5) in which the controller was able to clamp mean body temperature to the setpoint thereby preventing heat storage. Although exercise rate (75 W) was the same, sweating and warm discomfort occurred in some cases due to the individual rectal temperature rise. Another source of discomfort were delays or paradoxical time courses of rectal temperature at the start or end of exercise which were responsible for a delayed onset of cooling or heating. To avoid these effects, the oxygen consumption signal, which is very fast and directly correlated to the exercise rate, was added to the control loop. Each increase of this parameter above its resting level lowered suit temperature. As heat storage should not be completely rejected by this new signal pathway, the controller for mean body temperature still remained active. The repetition of the experiments showed that the load error in the control loop was smaller and the comfort level in transient phases higher. For a further improvement of this concept it is recommended that the weighting coefficients be tuned to the individual requirements.

Limits to sustained energy intake. XVI. Body temperature and physical activity of female mice during pregnancy.

PubMed

Gamo, Yuko; Bernard, Amelie; Mitchell, Sharon E; Hambly, Catherine; Al Jothery, Aqeel; Vaanholt, Lobke M; Król, Elzbieta; Speakman, John R

2013-06-15

Lactation is the most energy-demanding phase of mammalian reproduction, and lactation performance may be affected by events during pregnancy. For example, food intake may be limited in late pregnancy by competition for space in the abdomen between the alimentary tract and fetuses. Hence, females may need to compensate their energy budgets during pregnancy by reducing activity and lowering body temperature. We explored the relationships between energy intake, body mass, body temperature and physical activity throughout pregnancy in the MF1 mouse. Food intake and body mass of 26 females were recorded daily throughout pregnancy. Body temperature and physical activity were monitored every minute for 23 h a day by implanted transmitters. Body temperature and physical activity declined as pregnancy advanced, while energy intake and body mass increased. Compared with a pre-mating baseline period, mice increased energy intake by 56% in late pregnancy. Although body temperature declined as pregnancy progressed, this served mostly to reverse an increase between baseline and early pregnancy. Reduced physical activity may compensate the energy budget of pregnant mice but body temperature changes do not. Over the last 3 days of pregnancy, food intake declined. Individual variation in energy intake in the last phase of pregnancy was positively related to litter size at birth. As there was no association between the increase in body mass and the decline in intake, we suggest the decline was not caused by competition for abdominal space. These data suggest overall reproductive performance is probably not constrained by events during pregnancy.

Temperature monitoring device and thermocouple assembly therefor

DOEpatents

Grimm, Noel P.; Bauer, Frank I.; Bengel, Thomas G.; Kothmann, Richard E.; Mavretish, Robert S.; Miller, Phillip E.; Nath, Raymond J.; Salton, Robert B.

1991-01-01

A temperature monitoring device for measuring the temperature at a surface of a body, composed of: at least one first thermocouple and a second thermocouple; support members supporting the thermocouples for placing the first thermocouple in contact with the body surface and for maintaining the second thermocouple at a defined spacing from the body surface; and a calculating circuit connected to the thermocouples for receiving individual signals each representative of the temperature reading produced by a respective one of the first and second thermocouples and for producing a corrected temperature signal having a value which represents the temperature of the body surface and is a function of the difference between the temperature reading produced by the first thermocouple and a selected fraction of the temperature reading provided by the second thermocouple.

Mitochondrial Impairment in Cerebrovascular Endothelial Cells is Involved in the Correlation between Body Temperature and Stroke Severity

PubMed Central

Hu, Heng; Doll, Danielle N.; Sun, Jiahong; Lewis, Sara E.; Wimsatt, Jeffrey H.; Kessler, Matthew J.; Simpkins, James W.; Ren, Xuefang

2016-01-01

Stroke is the second leading cause of death worldwide. The prognostic influence of body temperature on acute stroke in patients has been recently reported; however, hypothermia has confounded experimental results in animal stroke models. This work aimed to investigate how body temperature could prognose stroke severity as well as reveal a possible mitochondrial mechanism in the association of body temperature and stroke severity. Lipopolysaccharide (LPS) compromises mitochondrial oxidative phosphorylation in cerebrovascular endothelial cells (CVECs) and worsens murine experimental stroke. In this study, we report that LPS (0.1 mg/kg) exacerbates stroke infarction and neurological deficits, in the mean time LPS causes temporary hypothermia in the hyperacute stage during 6 hours post-stroke. Lower body temperature is associated with worse infarction and higher neurological deficit score in the LPS-stroke study. However, warming of the LPS-stroke mice compromises animal survival. Furthermore, a high dose of LPS (2 mg/kg) worsens neurological deficits, but causes persistent severe hypothermia that conceals the LPS exacerbation of stroke infarction. Mitochondrial respiratory chain complex I inhibitor, rotenone, replicates the data profile of the LPS-stroke study. Moreover, we have confirmed that rotenone compromises mitochondrial oxidative phosphorylation in CVECs. Lastly, the pooled data analyses of a large sample size (n=353) demonstrate that stroke mice have lower body temperature compared to sham mice within 6 hours post-surgery; the body temperature is significantly correlated with stroke outcomes; linear regression shows that lower body temperature is significantly associated with higher neurological scores and larger infarct volume. We conclude that post-stroke body temperature predicts stroke severity and mitochondrial impairment in CVECs plays a pivotal role in this hypothermic response. These novel findings suggest that body temperature is prognostic for stroke severity in experimental stroke animal models and may have translational significance for clinical stroke patients - targeting endothelial mitochondria may be a clinically useful approach for stroke therapy. PMID:26816660

Body temperature change and outcomes in patients undergoing long-distance air medical transport.

PubMed

Nakajima, Mikio; Aso, Shotaro; Yasunaga, Hideo; Shirokawa, Masamitsu; Nakano, Tomotsugu; Miyakuni, Yasuhiko; Goto, Hideaki; Yamaguchi, Yoshihiro

2018-04-30

Short-distance air medical transport for adult emergency patients does not significantly affect patients' body temperature and outcomes. This study aimed to examine the influence of long-distance air medical transport on patients' body temperatures and the relationship between body temperature change and mortality. We retrospectively enrolled consecutive patients transferred via helicopter or plane from isolated islands to an emergency medical center in Tokyo, Japan between April 2010 and December 2016. Patients' average body temperature was compared before and after air transport using a paired t-test, and corrections between body temperature change and flight duration were calculated using Pearson's correlation coefficient. Multivariable logistic regression models were then used to examine the association between body temperature change and in-hospital mortality. Of 1253 patients, the median age was 72 years (interquartile range, 60-82 years) and median flight duration was 71 min (interquartile range, 54-93 min). In-hospital mortality was 8.5%, and average body temperature was significantly different before and after air transport (36.7 °C versus 36.3 °C; difference: -0.36 °C; 95% confidence interval, -0.30 to -0.42; p < 0.001). There was no correlation between body temperature change and flight duration (r = 0.025, p = 0.371). In-hospital death was significantly associated with (i) hyperthermia (>38.0 °C) or normothermia (36.0-37.9 °C) before air transport and hypothermia after air transport (odds ratio, 2.08; 95% confidence interval, 1.20-3.63; p = 0.009), and (ii) winter season (odds ratio, 2.15; 95% confidence interval, 1.08-4.27; p = 0.030). Physicians should consider body temperature change during long-distance air transport in patients with not only hypothermia but also normothermia or hyperthermia before air transport, especially in winter. Copyright © 2018 Elsevier Inc. All rights reserved.

Importance of Early Postoperative Body Temperature Management for Treatment of Subarachnoid Hemorrhage.

PubMed

Suehiro, Eiichi; Sadahiro, Hirokazu; Goto, Hisaharu; Oku, Takayuki; Oka, Fumiaki; Fujiyama, Yuichi; Shirao, Satoshi; Yoneda, Hiroshi; Koizumi, Hiroyasu; Ishihara, Hideyuki; Suzuki, Michiyasu

2016-06-01

The importance of acute-phase brain temperature management is widely accepted for prevention of exacerbation of brain damage by a high body temperature. In this study, we investigated the influence of body temperature in the early postoperative period on the outcomes of 62 patients with subarachnoid hemorrhage who were admitted to our department. Body temperature was measured from day 4 to day 14 after onset. The patients were divided into those treated with surgical clipping (clip group) and coil embolization (coil group), those graded I-III (mild) and IV-V (severe) based on the Hunt & Hess classification on admission, those with and without development of delayed cerebral ischemia (DCI), and those with favorable and poor outcomes. Body temperatures throughout the hospital stay were compared in each group. There was no significant difference in body temperature between the clip and coil groups or between the mild and severe groups, but body temperature was significantly higher in patients with DCI compared to those without DCI, and in patients with a poor outcome compared to those with a favorable outcome. Fever in the early postoperative period of subarachnoid hemorrhage is associated with development of DCI and a poor outcome. Copyright © 2016 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Body/bone-marrow differential-temperature sensor

NASA Technical Reports Server (NTRS)

Anselmo, V. J.; Berdahl, C. M.

1978-01-01

Differential-temperature sensor developed to compare bone-marrow and body temperature in leukemia patients uses single stable amplifier to monitor temperature difference recorded by thermocouples. Errors are reduced by referencing temperatures to each other, not to separate calibration points.

The influence of metabolic heat production on body temperature of a small lizard, Anolis carolinensis.

PubMed

Brown, Richard P; Au, Timothy

2009-06-01

Little is known about the impact of increased metabolism on body temperatures of small ectotherms. We found that postprandial metabolic rates of 5 g Anolis carolinensis lizards were elevated by factorial increases of 2.3+/-1.0 (mean+/-S.E.) at 26 degrees C and 3.8+/-2.1 at 30 degrees C over their fasting rates. Cloacal body temperatures exceeded environmental temperatures by a small amount in fasted individuals (26 degrees C: 0.3+/-0.02 degrees C, 30 degrees C: 0.3+/-0.02 degrees C), and by a significantly larger amount in fed individuals (26 degrees C: 1.0+/-0.06 degrees C, 30 degrees C: 0.8+/-0.08 degrees C). We conclude that an increased metabolic rate due to specific dynamic action leads to a small but significant elevation of body temperature in this species. Comparisons with thermal increments reported for a large (750 g) varanid lizard suggest that body size has only a minor influence on body-air temperature differentials of ectotherms. This is consistent with theoretical predictions. Finally, endogenous heat production could help elevate body temperatures in the wild and therefore play a minor role in thermoregulation.

Elevated body temperature in ischemic stroke associated with neurological improvement.

PubMed

Khanevski, A N; Naess, H; Thomassen, L; Waje-Andreassen, U; Nacu, A; Kvistad, C E

2017-11-01

Some studies suggest that high body temperature within the first few hours of ischemic stroke onset is associated with improved outcome. We hypothesized an association between high body temperature on admission and detectable improvement within 6-9 hours of stroke onset. Consecutive ischemic stroke patients with NIHSS scores obtained within 3 hours and in the interval 6-9 hours after stroke onset were included. Body temperature was measured on admission. A total of 315 patients with ischemic stroke were included. Median NIHSS score on admission was 6. Linear regression showed that NIHSS score 6-9 hours after stroke onset was inversely associated with body temperature on admission after adjusting for confounders including NIHSS score <3 hours after stroke onset (P<.001). The same result was found in patients with proximal middle cerebral occlusion on admission. We found an inverse association between admission body temperature and neurological improvement within few hours after admission. This finding may be limited to patients with documented proximal middle cerebral artery occlusion on admission and suggests a beneficial effect of higher body temperature on clot lysis within the first three hours. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Being cool: how body temperature influences ageing and longevity.

PubMed

Keil, Gerald; Cummings, Elizabeth; de Magalhães, João Pedro

2015-08-01

Temperature is a basic and essential property of any physical system, including living systems. Even modest variations in temperature can have profound effects on organisms, and it has long been thought that as metabolism increases at higher temperatures so should rates of ageing. Here, we review the literature on how temperature affects longevity, ageing and life history traits. From poikilotherms to homeotherms, there is a clear trend for lower temperature being associated with longer lifespans both in wild populations and in laboratory conditions. Many life-extending manipulations in rodents, such as caloric restriction, also decrease core body temperature. Nonetheless, an inverse relationship between temperature and lifespan can be obscured or reversed, especially when the range of body temperatures is small as in homeotherms. An example is observed in humans: women appear to have a slightly higher body temperature and yet live longer than men. The mechanisms involved in the relationship between temperature and longevity also appear to be less direct than once thought with neuroendocrine processes possibly mediating complex physiological responses to temperature changes. Lastly, we discuss species differences in longevity in mammals and how this relates to body temperature and argue that the low temperature of the long-lived naked mole-rat possibly contributes to its exceptional longevity.

Body temperature and resistance to evaporative water loss in tropical Australian frogs.

PubMed

Tracy, Christopher R; Christian, Keith A; Betts, Gregory; Tracy, C Richard

2008-06-01

Although the skin of most amphibians measured to date offers no resistance to evaporative water loss (EWL), some species, primarily arboreal frogs, produce skin secretions that increase resistance to EWL. At high air temperatures, it may be advantageous for amphibians to increase EWL as a means to decrease body temperature. In Australian hylid frogs, most species do not decrease their resistance at high air temperature, but some species with moderate resistance (at moderate air temperatures) gradually decrease resistance with increasing air temperature, and some species with high resistance (at moderate air temperatures) abruptly decrease resistance at high air temperatures. Lower skin resistance at high air temperatures decreases the time to desiccation, but the lower body temperatures allow the species to avoid their critical thermal maximum (CT(Max)) body temperatures. The body temperatures of species with low to moderate resistances to EWL that do not adjust resistance at high air temperatures do not warm to their CT(Max), although for some species, this is because they have high CT(Max) values. As has been reported previously for resistance to EWL generally, the response pattern of change of EWL at high air temperatures has apparently evolved independently among Australian hylids. The mechanisms involved in causing resistance and changes in resistance are unknown.

Isotopic ordering in eggshells reflects body temperatures and suggests differing thermophysiology in two Cretaceous dinosaurs.

PubMed

Eagle, Robert A; Enriquez, Marcus; Grellet-Tinner, Gerald; Pérez-Huerta, Alberto; Hu, David; Tütken, Thomas; Montanari, Shaena; Loyd, Sean J; Ramirez, Pedro; Tripati, Aradhna K; Kohn, Matthew J; Cerling, Thure E; Chiappe, Luis M; Eiler, John M

2015-10-13

Our understanding of the evolutionary transitions leading to the modern endothermic state of birds and mammals is incomplete, partly because tools available to study the thermophysiology of extinct vertebrates are limited. Here we show that clumped isotope analysis of eggshells can be used to determine body temperatures of females during periods of ovulation. Late Cretaceous titanosaurid eggshells yield temperatures similar to large modern endotherms. In contrast, oviraptorid eggshells yield temperatures lower than most modern endotherms but ∼ 6 °C higher than co-occurring abiogenic carbonates, implying that this taxon did not have thermoregulation comparable to modern birds, but was able to elevate its body temperature above environmental temperatures. Therefore, we observe no strong evidence for end-member ectothermy or endothermy in the species examined. Body temperatures for these two species indicate that variable thermoregulation likely existed among the non-avian dinosaurs and that not all dinosaurs had body temperatures in the range of that seen in modern birds.

Heat transfer in fish: are short excursions between habitats a thermoregulatory behaviour to exploit resources in an unfavourable thermal environment?

PubMed

Pépino, Marc; Goyer, Katerine; Magnan, Pierre

2015-11-01

Temperature is the primary environmental factor affecting physiological processes in ectotherms. Heat-transfer models describe how the fish's internal temperature responds to a fluctuating thermal environment. Specifically, the rate coefficient (k), defined as the instantaneous rate of change in body temperature in relation to the difference between ambient and body temperature, summarizes the combined effects of direct thermal conduction through body mass, passive convection (intracellular and intercellular fluids) and forced convective heat transfer (cardiovascular system). The k-coefficient is widely used in fish ecology to understand how body temperature responds to changes in water temperature. The main objective of this study was to estimate the k-coefficient of brook charr equipped with internal temperature-sensitive transmitters in controlled laboratory experiments. Fish were first transferred from acclimation tanks (10°C) to tanks at 14, 19 or 23°C (warming experiments) and were then returned to the acclimation tanks (10°C; cooling experiments), thus producing six step changes in ambient temperature. We used non-linear mixed models to estimate the k-coefficient. Model comparisons indicated that the model incorporating the k-coefficient as a function of absolute temperature difference (dT: 4, 9 and 13°C) best described body temperature change. By simulating body temperature in a heterogeneous thermal environment, we provide theoretical predictions of maximum excursion duration between feeding and resting areas. Our simulations suggest that short (i.e. <60 min) excursions could be a common thermoregulatory behaviour adopted by cold freshwater fish species to sustain body temperature below a critical temperature threshold, enabling them to exploit resources in an unfavourable thermal environment. © 2015. Published by The Company of Biologists Ltd.

Effect of environmental temperature on body temperature and metabolic heat production in a heterothermic rodent, Spermophilus tereticaudus.

PubMed

Wooden, K Mark; Walsberg, Glenn E

2002-07-01

This study quantifies the thermoregulatory ability and energetics of a mammal, the round-tailed ground squirrel Spermophilus tereticaudus, that can relax thermoregulatory limits without becoming inactive. We measured body temperature and metabolic rate in animals exposed for short periods (1 h) to air temperatures ranging from 10 to 45 degrees C and for long periods (8 h) to air temperatures ranging from 10 to 30 degrees C. Within 45 min of exposure to air temperatures ranging from 10 to 45 degrees C, the mean body temperatures of alert and responsive animals ranged from 32.1 degrees C (T(air)=10 degrees C) to 40.4 degrees C (T(air)=45 degrees C). This thermolability provided significant energetic savings below the thermoneutral zone, ranging from 0.63 W (18 %) at 10 degrees C to 0.43 W (43 %) at 30 degrees C. When exposed for 8 h to air temperatures between 10 and 30 degrees C, animals varied their body temperature significantly over time. At all air temperatures, the lowest body temperature (maintained for at least 1 h) was 31.2 degrees C. The highest body temperatures (maintained for at least 1 h) were 33.6 degrees C at 10 degrees C, 35.3 degrees C at 20 degrees C and 36.3 degrees C at 30 degrees C. The energetic savings realized by maintaining the minimum rather than the maximum body temperature was 0.80 W (25 %) at 10 degrees C, 0.71 W (33 %) at 20 degrees C and 0.40 W (47 %) at 30 degrees C. This study demonstrates in several ways the ability of this species to adjust energy expenditure through heterothermy.

Miniature ingestible telemeter devices to measure deep-body temperature

NASA Technical Reports Server (NTRS)

Pope, J. M.; Fryer, T. B. (Inventor)

1976-01-01

A telemetry device comprised of a pill-size ingestible transmitter developed to obtain deep body temperature measurements of a human is described. The device has particular utility in the medical field where deep body temperatures provide an indication of general health.

Short communication: Changes in body temperature of calves up to 2 months of age as affected by time of day, age, and ambient temperature.

PubMed

Hill, T M; Bateman, H G; Suarez-Mena, F X; Dennis, T S; Schlotterbeck, R L

2016-11-01

Extensive measurements of calf body temperature are limited in the literature. In this study, body temperatures were collected by taping a data logger to the skin over the tail vein opposing the rectum of Holstein calves between 4 and 60d of age during 3 different periods of the summer and fall. The summer period was separated into moderate (21-33°C average low to high) and hot (25-37°C) periods, whereas the fall exhibited cool (11-19°C) ambient temperatures. Tail temperatures were compared in a mixed model ANOVA using ambient temperature, age of calf, and time of day (10-min increments) as fixed effects and calf as a random effect. Measures within calf were modeled as repeated effects of type autoregressive 1. Calf temperature increased 0.0325°C (±0.00035) per 1°C increase in ambient temperature. Body temperature varied in a distinct, diurnal pattern with time of day, with body temperatures being lowest around 0800h and highest between 1700 and 2200h. During periods of hot weather, the highest calf temperature was later in the day (~2200h). Calf minimum, maximum, and average body temperatures were all higher in hot than in moderate periods and higher in moderate than in cool periods. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Ectotherm thermal stress and specialization across altitude and latitude.

PubMed

Buckley, Lauren B; Miller, Ethan F; Kingsolver, Joel G

2013-10-01

Gradients of air temperature, radiation, and other climatic factors change systematically but differently with altitude and latitude. We explore how these factors combine to produce altitudinal and latitudinal patterns of body temperature, thermal stress, and seasonal overlap that differ markedly from patterns based solely on air temperature. We use biophysical models to estimate body temperature as a function of an organism's phenotype and environmental conditions (air and surface temperatures and radiation). Using grasshoppers as a case study, we compare mean body temperatures and the incidence of thermal extremes along altitudinal gradients both under past and current climates. Organisms at high elevation can experience frequent thermal stress despite generally cooler air temperatures due to high levels of solar radiation. Incidences of thermal stress have increased more rapidly than have increases in mean conditions due to recent climate change. Increases in air temperature have coincided with shifts in cloudiness and solar radiation, which can exacerbate shifts in body temperature. We compare altitudinal thermal gradients and their seasonality between tropical and temperate mountains to ask whether mountain passes pose a greater physiological barrier in the tropics (Janzen's hypothesis). We find that considering body temperature rather than air temperature generally increases the amount of overlap in thermal conditions along gradients in elevation and thus decreases the physiological barrier posed by tropical mountains. Our analysis highlights the limitations of predicting thermal stress based solely on air temperatures, and the importance of considering how phenotypes influence body temperatures.

Thermal biology in two syntopic lizards, Phymaturus extrilidus and Liolaemus parvus, in the Puna region of Argentina.

PubMed

Gómez Alés, Rodrigo; Acosta, Juan Carlos; Laspiur, Alejandro

2017-08-01

Body temperature is the most important ecophysiological variable affecting reptiles' life history. Moreover, thermoregulation in ectotherms implies a struggle to reach preferred temperatures in natural conditions due to the influence of biotic and abiotic factors. Our objective was to evaluate and compare the thermal biology of two syntopic species, Phymaturus extrilidus and Liolaemus parvus, in the Puna region of San Juan, Argentina. We determined body temperature (T b ), micro-environmental temperatures (T a and T s ) and operative temperatures (T e ) in the field. In the laboratory, we measured preferred temperatures (T pref ) and calculated the index of thermoregulatory efficiency (E). Neither body temperatures in the field nor preferred temperatures varied between seasons and sexes. Body temperatures were lower than preferred temperatures for both species. Nevertheless, regardless of the low thermal offer available in habitat, both species did achieve body temperatures higher than operative temperatures during activity. Thermoregulatory effectiveness was moderate in P. extrilidus (E=0.65), while L. parvus presented greater thermoregulatory efficiency (E=0.78). We conclude that under the rigorous climate conditions of the Puna, Phymaturus extrilidus and Liolaemus parvus are able to actively and efficiently thermoregulate, maintaining body temperatures close to the preferred and higher than those of its habitat. Differences in thermal characteristics between Phymaturus extrilidus and Liolaemus parvus are a consequence of differential limitations imposed on each species by the environment and of forces inherent to their life histories. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of heat stress on body temperature in healthy early postpartum dairy cows.

PubMed

Burfeind, O; Suthar, V S; Heuwieser, W

2012-12-01

Measurement of body temperature is the most common method for an early diagnosis of sick cows in fresh cow protocols currently used on dairy farms. Thresholds for fever range from 39.4 °C to 39.7 °C. Several studies attempted to describe normal temperature ranges for healthy dairy cows in the early puerperium. However, the definition of a healthy cow is variable within these studies. It is challenging to determine normal temperature ranges for healthy cows because body temperature is usually included in the definition. Therefore, the objectives of this study were to identify factors that influence body temperature in healthy dairy cows early postpartum and to determine normal temperature ranges for healthy cows that calved in a moderate (temperature humidity index: 59.8 ± 3.8) and a hot period (temperature humidity index: 74.1 ± 4.4), respectively, excluding body temperature from the definition of the health status. Furthermore, the prevalence of fever was calculated for both periods separately. A subset of 17 (moderate period) and 15 cows (hot period) were used for analysis. To ensure their uterine health only cows with a serum haptoglobin concentration ≤ 1.1 g/L were included in the analysis. Therefore, body temperature could be excluded from the definition. A vaginal temperature logger that measured vaginal temperature every 10 min was inserted from Day 2 to 10 after parturition. Additionally rectal temperature was measured twice daily. Day in milk (2 to 10), period (moderate and hot), and time of day had an effect on rectal and vaginal temperature. The prevalence of fever (≥ 39.5 °C) was 7.4% and 28.1% for rectal temperature in the moderate and hot period, respectively. For vaginal temperature (07.00 to 11.00 h) it was 10% and 33%, respectively, considering the same threshold and period. This study demonstrates that body temperature in the early puerperium is influenced by several factors (day in milk, climate, time of day). Therefore, these factors have to be considered when interpreting body temperature measures to identify sick cows. Furthermore, the prevalence of fever considering different thresholds is higher during hot than moderate periods. However, even in a moderate period healthy cows can exhibit a body temperature that is considered as fever. This fact clearly illustrates that fever alone should not be considered the decision criterion whether a cow is allocated to an antibiotic treatment, although it is the most important one that is objectively measurable. Copyright © 2012 Elsevier Inc. All rights reserved.

Thermal dependence of sprint performance in the lizard Psammodromus algirus along a 2200-meter elevational gradient: Cold-habitat lizards do not perform better at low temperatures.

PubMed

Zamora-Camacho, Francisco Javier; Rubiño-Hispán, María Virtudes; Reguera, Senda; Moreno-Rueda, Gregorio

2015-08-01

Sprint speed has a capital relevance in most animals' fitness, mainly for fleeing from predators. Sprint performance is maximal within a certain range of body temperatures in ectotherms, whose thermal upkeep relies on exogenous thermal sources. Ectotherms can respond to diverse thermal environments either by shifting their thermal preferences or maintaining them through different adaptive mechanisms. Here, we tested whether maximum sprint speed of a lizard that shows conservative thermal ecology along a 2200-meter elevational gradient differs with body temperature in lizards from different elevations. Lizards ran faster at optimum than at suboptimum body temperature. Notably, high-elevation lizards were not faster than mid- and low-elevation lizards at suboptimum body temperature, despite their low-quality thermal environment. This result suggests that both preferred body temperature and thermal dependence of speed performance are co-adapted along the elevational gradient. High-elevation lizards display a number of thermoregulatory strategies that allow them to achieve high optimum body temperatures in a low thermal-quality habitat and thus maximize speed performance. As for reproductive condition, we did not find any effect of it on sprint speed, or any significant interaction with elevation or body temperature. However, strikingly, gravid females were significantly slower than males and non-gravid females at suboptimum temperature, but performed similarly well at optimal temperature. Copyright © 2015 Elsevier Ltd. All rights reserved.

Wearable sensors in intelligent clothing for measuring human body temperature based on optical fiber Bragg grating.

PubMed

Li, Hongqiang; Yang, Haijing; Li, Enbang; Liu, Zhihui; Wei, Kejia

2012-05-21

Measuring body temperature is considerably important to physiological studies as well as clinical investigations. In recent years, numerous observations have been reported and various methods of measurement have been employed. The present paper introduces a novel wearable sensor in intelligent clothing for human body temperature measurement. The objective is the integration of optical fiber Bragg grating (FBG)-based sensors into functional textiles to extend the capabilities of wearable solutions for body temperature monitoring. In addition, the temperature sensitivity is 150 pm/°C, which is almost 15 times higher than that of a bare FBG. This study combines large and small pipes during fabrication to implant FBG sensors into the fabric. The law of energy conservation of the human body is considered in determining heat transfer between the body and its clothing. The mathematical model of heat transmission between the body and clothed FBG sensors is studied, and the steady-state thermal analysis is presented. The simulation results show the capability of the material to correct the actual body temperature. Based on the skin temperature obtained by the weighted average method, this paper presents the five points weighted coefficients model using both sides of the chest, armpits, and the upper back for the intelligent clothing. The weighted coefficients of 0.0826 for the left chest, 0.3706 for the left armpit, 0.3706 for the right armpit, 0.0936 for the upper back, and 0.0826 for the right chest were obtained using Cramer's Rule. Using the weighting coefficient, the deviation of the experimental result was ± 0.18 °C, which favors the use for clinical armpit temperature monitoring. Moreover, in special cases when several FBG sensors are broken, the weighted coefficients of the other sensors could be changed to obtain accurate body temperature.

Cold-sensing regulates Drosophila growth through insulin-producing cells

PubMed Central

Li, Qiaoran; Gong, Zhefeng

2015-01-01

Across phyla, body size is linked to climate. For example, rearing fruit flies at lower temperatures results in bigger body sizes than those observed at higher temperatures. The underlying molecular basis of this effect is poorly understood. Here we provide evidence that the temperature-dependent regulation of Drosophila body size depends on a group of cold-sensing neurons and insulin-producing cells (IPCs). Electrically silencing IPCs completely abolishes the body size increase induced by cold temperature. IPCs are directly innervated by cold-sensing neurons. Stimulation of these cold-sensing neurons activates IPCs, promotes synthesis and secretion of Drosophila insulin-like peptides and induces a larger body size, mimicking the effects of rearing the flies in cold temperature. Taken together, these findings reveal a neuronal circuit that mediates the effects of low temperature on fly growth. PMID:26648410

Hibernation in black bears: independence of metabolic suppression from body temperature.

PubMed

Tøien, Øivind; Blake, John; Edgar, Dale M; Grahn, Dennis A; Heller, H Craig; Barnes, Brian M

2011-02-18

Black bears hibernate for 5 to 7 months a year and, during this time, do not eat, drink, urinate, or defecate. We measured metabolic rate and body temperature in hibernating black bears and found that they suppress metabolism to 25% of basal rates while regulating body temperature from 30° to 36°C, in multiday cycles. Heart rates were reduced from 55 to as few as 9 beats per minute, with profound sinus arrhythmia. After returning to normal body temperature and emerging from dens, bears maintained a reduced metabolic rate for up to 3 weeks. The pronounced reduction and delayed recovery of metabolic rate in hibernating bears suggest that the majority of metabolic suppression during hibernation is independent of lowered body temperature.

Intraoperative use of a reflective blanket (Sirius rescue sheet) for temperature management in dogs less than 10 kg.

PubMed

Tünsmeyer, J; Bojarski, I; Nolte, I; Kramer, S

2009-07-01

To compare the effects of the Sirius rescue sheet with gel pads versus gel pads alone on intraoperative body temperature in dogs less than 10 kg. Forty small breed dogs undergoing elective surgical procedures were randomly assigned to two groups. One group was intraoperatively laid on warmed gel pads, and the other group was additionally wrapped in a Sirius rescue sheet. Oesophageal body temperature was determined every 10 minutes and compared between groups. Temperature of gel pads was measured preoperatively and postoperatively to compare heat loss of the gel pads between groups. The body temperature of dogs wrapped with the Sirius rescue sheet increased intraoperatively. In dogs just lying on warmed gel pads, a decrease in mean body temperature was revealed and mean body temperatures differed between groups after 40 minutes. Extent of heat loss from the gel pads did not differ between the groups. The Sirius rescue sheet, used in addition to warmed gel pads, led to higher intraoperative body temperatures in small breed dogs undergoing surgical procedures to the extremities and the head. The cost-effectiveness and ease of handling make this a useful addition to clinical practice.

CH-19 sweet, a non-pungent cultivar of red pepper, increased body temperature and oxygen consumption in humans.

PubMed

Ohnuki, K; Niwa, S; Maeda, S; Inoue, N; Yazawa, S; Fushiki, T

2001-09-01

We investigated the effect of CH-19 Sweet, a non-pungent cultivar of red pepper, on body temperature and oxygen consumption in humans. CH-19 Sweet was given to 11 healthy volunteers, and core body temperature, body surface temperature and oxygen consumption were measured. The control group ingested California-Wandar, which contained neither capsaicin nor capsiate. The core body temperature in the CH-19 Sweet group was significantly higher than that in the control group (P<0.01). The forehead temperature measured by infrared thermography in the CH-19 Sweet group was significantly higher than that in the control group. The body surface temperature was increased for about 20 min after consumption of CH-19 Sweet intake, and the neck temperature was significantly higher (P<0.001) than when the subjects consumed California-Wandar. We also measured respiratory gas by indirect calorimetry while subjects wore a face mask. A significant difference was detected in oxygen consumption between the two groups, and the value was significantly higher in the CH-19 Sweet group (P<0.03). These results suggest that CH-19 Sweet increased thermogenesis and energy consumption.

Influence of winter temperature and simulated climate change on body mass and fat body depletion during diapause in adults of the solitary bee, Osmia rufa (Hymenoptera: Megachilidae).

PubMed

Fliszkiewicz, Monika; Giejdasz, Karol; Wasielewski, Oskar; Krishnan, Natraj

2012-12-01

The influence of simulated climate change on body weight and depletion of fat body reserves was studied during diapause in the European solitary bee Osmia rufa L. (Hymenoptera: Megachilidae). Insects (females) were reared and collected from outdoor nests from September to March. One cohort of females was weighed and dissected immediately for analyses, whereas another cohort was subjected to simulated warmer temperature (15°C for 7 d) before analyses. A gradual decline in body mass and fat body content was recorded with declining temperatures from September to January in female bees from natural conditions. Temperature increased gradually from January to March with a further decline in body mass and fat body content. The fat body development index dropped from five in September-October (≈ 89% individuals) to four for the period from November to February (≈ 84% individuals) and further to three in March (95% individuals) before emergence. Simulated warmer winter temperature also resulted in a similar decline in body weight and fat body content; however, body weight and fat body content declined faster. The fat body development index dropped to three in December in the majority of individuals and continued at this level until March just before emergence. Taken together, our data indicate an earlier depletion of fat body reserves under simulated climate change conditions that may impact ovarian development and reproductive fitness in O. rufa.

Hemoglobin Dynamics in Red Blood Cells: Correlation to Body Temperature

PubMed Central

Stadler, A. M.; Digel, I.; Artmann, G. M.; Embs, J. P.; Zaccai, G.; Büldt, G.

2008-01-01

A transition in hemoglobin behavior at close to body temperature has been discovered recently by micropipette aspiration experiments on single red blood cells (RBCs) and circular dichroism spectroscopy on hemoglobin solutions. The transition temperature was directly correlated to the body temperatures of a variety of species. In an exploration of the molecular basis for the transition, we present neutron scattering measurements of the temperature dependence of hemoglobin dynamics in whole human RBCs in vivo. The data reveal a change in the geometry of internal protein motions at 36.9°C, at human body temperature. Above that temperature, amino acid side-chain motions occupy larger volumes than expected from normal temperature dependence, indicating partial unfolding of the protein. Global protein diffusion in RBCs was also measured and the findings compared favorably with theoretical predictions for short-time self-diffusion of noncharged hard-sphere colloids. The results demonstrated that changes in molecular dynamics in the picosecond time range and angstrom length scale might well be connected to a macroscopic effect on whole RBCs that occurs at body temperature. PMID:18708462

Hemoglobin dynamics in red blood cells: correlation to body temperature.

PubMed

Stadler, A M; Digel, I; Artmann, G M; Embs, J P; Zaccai, G; Büldt, G

2008-12-01

A transition in hemoglobin behavior at close to body temperature has been discovered recently by micropipette aspiration experiments on single red blood cells (RBCs) and circular dichroism spectroscopy on hemoglobin solutions. The transition temperature was directly correlated to the body temperatures of a variety of species. In an exploration of the molecular basis for the transition, we present neutron scattering measurements of the temperature dependence of hemoglobin dynamics in whole human RBCs in vivo. The data reveal a change in the geometry of internal protein motions at 36.9 degrees C, at human body temperature. Above that temperature, amino acid side-chain motions occupy larger volumes than expected from normal temperature dependence, indicating partial unfolding of the protein. Global protein diffusion in RBCs was also measured and the findings compared favorably with theoretical predictions for short-time self-diffusion of noncharged hard-sphere colloids. The results demonstrated that changes in molecular dynamics in the picosecond time range and angstrom length scale might well be connected to a macroscopic effect on whole RBCs that occurs at body temperature.

Influences of sex, ontogeny and body size on the thermal ecology of Liolaemus lutzae (Squamata, Liolaemidae) in a restinga remnant in Southeastern Brazil.

PubMed

Maia-Carneiro, Thiago; Rocha, Carlos Frederico Duarte

2013-01-01

Variations in body temperature (Tb) of lizards can be partially explained by intrinsic factors such as sex, ontogeny and body size. Liolaemus lutzae is a lizard species restricted to restingas in the Brazilian coast in the state of Rio de Janeiro. Herein, we studied sexual dimorphism and influences of sex, ontogeny, and body size to the Tb of L. lutzae. Adult males were larger than adult females, probably due to both intersexual selection and intra-sexual selection. There was intersexual difference in lizards' Tb (males hotter than females), but Tb did not differ after factored out for the effects of body size. The mean Tb of juvenile lizards was higher than that of adults after factored out for the effect of body mass. It is possible that adults may have excluded juveniles from microhabitats with better thermal regimes. Also, this might have occurred due to requirements of juveniles to maintain high growth rates. Forage searching for prey by juveniles also exposes them to high environmental temperatures. Juveniles also may have higher Tb than co-specific adults (relative to body mass) to favor prey capture. In absolute values, adult lizards tended to use microhabitats with lower temperatures than that used by juveniles, possibly to avoid risks of overheating and death. Body temperature and snout-vent length were positively related, as well as body temperature and body mass, presumably caused by the thermal inertia of the bodies (trend of a body to resist to changes in its temperature). Intrinsic factors such as sex, ontogeny and body size can affect the thermal ecology of L. lutzae, despite coastal habitat features to which they are exposed also influences the body temperature of active lizards in restinga habitats. Copyright © 2012 Elsevier Ltd. All rights reserved.

Thermoregulation and heat exchange in a nonuniform thermal environment during simulated extended EVA. Extravehicular activities

NASA Technical Reports Server (NTRS)

Koscheyev, V. S.; Leon, G. R.; Hubel, A.; Nelson, E. D.; Tranchida, D.

2000-01-01

BACKGROUND: Nonuniform heating and cooling of the body, a possibility during extended duration extravehicular activities (EVA), was studied by means of a specially designed water circulating garment that independently heated or cooled the right and left sides of the body. The purpose was to assess whether there was a generalized reaction on the finger in extreme contradictory temperatures on the body surface, as a potential heat status controller. METHOD: Eight subjects, six men and two women, were studied while wearing a sagittally divided experimental garment with hands exposed in the following conditions: Stage 1 baseline--total body garment inlet water temperature at 33 degrees C; Stage 2--left side inlet water temperature heated to 45 degrees C; right side cooled to 8 degrees C; Stage 3--left side inlet water temperature cooled to 8 degrees C, right side heated to 45 degrees C. RESULTS: Temperatures on each side of the body surface as well as ear canal temperature (Tec) showed statistically significant Stage x Side interactions, demonstrating responsiveness to the thermal manipulations. Right and left finger temperatures (Tfing) were not significantly different across stages; their dynamic across time was similar. Rectal temperature (Tre) was not reactive to prevailing cold on the body surface, and therefore not informative. Subjective perception of heat and cold on the left and right sides of the body was consistent with actual temperature manipulations. CONCLUSIONS: Tec and Tre estimates of internal temperature do not provide accurate data for evaluating overall thermal status in nonuniform thermal conditions on the body surface. The use of Tfing has significant potential in providing more accurate information on thermal status and as a feedback method for more precise thermal regulation of the astronaut within the EVA space suit.

Thermoregulation and heat exchange in a nonuniform thermal environment during simulated extended EVA. Extravehicular activities.

PubMed

Koscheyev, V S; Leon, G R; Hubel, A; Nelson, E D; Tranchida, D

2000-06-01

Nonuniform heating and cooling of the body, a possibility during extended duration extravehicular activities (EVA), was studied by means of a specially designed water circulating garment that independently heated or cooled the right and left sides of the body. The purpose was to assess whether there was a generalized reaction on the finger in extreme contradictory temperatures on the body surface, as a potential heat status controller. Eight subjects, six men and two women, were studied while wearing a sagittally divided experimental garment with hands exposed in the following conditions: Stage 1 baseline--total body garment inlet water temperature at 33 degrees C; Stage 2--left side inlet water temperature heated to 45 degrees C; right side cooled to 8 degrees C; Stage 3--left side inlet water temperature cooled to 8 degrees C, right side heated to 45 degrees C. Temperatures on each side of the body surface as well as ear canal temperature (Tec) showed statistically significant Stage x Side interactions, demonstrating responsiveness to the thermal manipulations. Right and left finger temperatures (Tfing) were not significantly different across stages; their dynamic across time was similar. Rectal temperature (Tre) was not reactive to prevailing cold on the body surface, and therefore not informative. Subjective perception of heat and cold on the left and right sides of the body was consistent with actual temperature manipulations. Tec and Tre estimates of internal temperature do not provide accurate data for evaluating overall thermal status in nonuniform thermal conditions on the body surface. The use of Tfing has significant potential in providing more accurate information on thermal status and as a feedback method for more precise thermal regulation of the astronaut within the EVA space suit.

The control effect of histamine on body temperature and respiratory function in IgE-dependent systemic anaphylaxis.

PubMed

Makabe-Kobayashi, Yoko; Hori, Yoshio; Adachi, Tetsuya; Ishigaki-Suzuki, Satsuki; Kikuchi, Yoshihiro; Kagaya, Yutaka; Shirato, Kunio; Nagy, András; Ujike, Azusa; Takai, Toshiyuki; Watanabe, Takehiko; Ohtsu, Hiroshi

2002-08-01

The systemic anaphylaxis reaction comprises various symptoms, including hypotension, changes in respiration pattern, and hypothermia. To elucidate the role of histamine in each of these symptoms, we induced the passive systemic anaphylaxis reaction in histidine decarboxylase gene knockout (HDC [-/-]) mice, which lack histamine. HDC(-/-) mice were generated by knocking out the HDC gene, which codes for the unique histamine-synthesizing enzyme. Twenty-four hours after the injection of IgE, HDC(+/+) and HDC(-/-) mice were injected with allergen and body temperature, blood pressure, and respiratory function were monitored in each mouse. Blood pressure dropped in both the HDC(-/-) mice and the HDC(+/+) mice. In contrast, respiratory frequency dropped and the expiratory respiration time was elongated only in the HDC(+/+) mice. Body temperature was decreased in the HDC(+/+) mice and was practically unchanged in the HDC(-/-) mice. Histamine receptor antagonists blocked the body temperature drop in the HDC(+/+) mice. Intravenous histamine induced similar patterns of body temperature decrease in the HDC(+/+) mice and the HDC(-/-) mice. Mast cell-deficient W/W (v) mice did not show the decrease in body temperature; this suggests that the histamine that contributed to the decrease in body temperature was derived from mast cells. According to the results of this investigation, in the passive systemic anaphylaxis reaction, respiratory frequency, expiratory time, and body temperature are shown to be controlled by the activity of histamine, but its contribution to blood pressure is negligible.

Pathophysiology of Temperature Regulation.

ERIC Educational Resources Information Center

Mitchell, D.; Laburn, Helen P.

1985-01-01

Discusses: (1) measurement of body temperature; (2) normal deviations from normal body temperature; (3) temperature in the very young and the very old; (4) abnormal liability of thermoregulation; (5) hyperthermia; (6) fever; and (7) hypothermia. (JN)

A simple method to predict body temperature of small reptiles from environmental temperature.

PubMed

Vickers, Mathew; Schwarzkopf, Lin

2016-05-01

To study behavioral thermoregulation, it is useful to use thermal sensors and physical models to collect environmental temperatures that are used to predict organism body temperature. Many techniques involve expensive or numerous types of sensors (cast copper models, or temperature, humidity, radiation, and wind speed sensors) to collect the microhabitat data necessary to predict body temperatures. Expense and diversity of requisite sensors can limit sampling resolution and accessibility of these methods. We compare body temperature predictions of small lizards from iButtons, DS18B20 sensors, and simple copper models, in both laboratory and natural conditions. Our aim was to develop an inexpensive yet accurate method for body temperature prediction. Either method was applicable given appropriate parameterization of the heat transfer equation used. The simplest and cheapest method was DS18B20 sensors attached to a small recording computer. There was little if any deficit in precision or accuracy compared to other published methods. We show how the heat transfer equation can be parameterized, and it can also be used to predict body temperature from historically collected data, allowing strong comparisons between current and previous environmental temperatures using the most modern techniques. Our simple method uses very cheap sensors and loggers to extensively sample habitat temperature, improving our understanding of microhabitat structure and thermal variability with respect to small ectotherms. While our method was quite precise, we feel any potential loss in accuracy is offset by the increase in sample resolution, important as it is increasingly apparent that, particularly for small ectotherms, habitat thermal heterogeneity is the strongest influence on transient body temperature.

The influence of environment, sex, and innate timing mechanisms on body temperature patterns of free-ranging black-tailed prairie dogs (Cynomys ludovicianus).

PubMed

Lehmer, Erin M; Bossenbroek, Jonathan M; Van Horne, Beatrice

2003-01-01

Mechanisms that influence body temperature patterns in black-tailed prairie dogs are not well understood. Previous research on both free-ranging and laboratory populations of black-tailed prairie dogs (Cynomys ludovicianus) has suggested that reductions in ambient temperature and food and water deprivation are the primary factors that stimulate torpor in this species. In other species, however, torpor has been shown to be influenced by a multitude of factors, including innate circadian and circannual timing mechanisms, energy status, and reproductive behaviors. Our objective was to clarify the influence of weather, sex, and intrinsic timing mechanisms on the body temperature patterns of free-ranging black-tailed prairie dogs. We monitored body temperatures of eight adult (>1 yr) prairie dogs from November 1999 to June 2000. Prairie dogs showed distinct daily and seasonal body temperature patterns, which reflected changes in ambient temperatures that occurred during these periods. These patterns of daily and seasonal heterothermy suggest that body temperature patterns of black-tailed prairie dogs may be driven by an innate timing mechanism. All prairie dogs entered torpor intermittently throughout winter and spring. Torpor bouts appeared to be influenced by precipitation and reductions in ambient temperature. Our results also suggest that reproductive behaviors and circadian timing may influence torpor in this species.

Body condition of Morelet’s Crocodiles (Crocodylus moreletii) from northern Belize

USGS Publications Warehouse

Mazzotti, Frank J.; Cherkiss, Michael S.; Brandt, Laura A.; Fujisaki, Ikuko; Hart, Kristen; Jeffery, Brian; McMurry, Scott T.; Platt, Steven G.; Rainwater, Thomas R.; Vinci, Joy

2012-01-01

Body condition factors have been used as an indicator of health and well-being of crocodilians. We evaluated body condition of Morelet's Crocodiles (Crocodylus moreletii) in northern Belize in relation to biotic (size, sex, and habitat) and abiotic (location, water level, and air temperature) factors. We also tested the hypothesis that high water levels and warm temperatures combine or interact to result in a decrease in body condition. Size class, temperature, and water level explained 20% of the variability in condition of Morelet's Crocodiles in this study. We found that adult crocodiles had higher condition scores than juveniles/subadults but that sex, habitat, and site had no effect. We confirmed our hypothesis that warm temperatures and high water levels interact to decrease body condition. We related body condition of Morelet's Crocodiles to natural fluctuations in air temperatures and water levels in northern Belize, providing baseline conditions for population and ecosystem monitoring.

Preoptic leptin signaling modulates energy balance independent of body temperature regulation.

PubMed

Yu, Sangho; Cheng, Helia; François, Marie; Qualls-Creekmore, Emily; Huesing, Clara; He, Yanlin; Jiang, Yanyan; Gao, Hong; Xu, Yong; Zsombok, Andrea; Derbenev, Andrei V; Nillni, Eduardo A; Burk, David H; Morrison, Christopher D; Berthoud, Hans-Rudolf; Münzberg, Heike

2018-05-15

The adipokine leptin acts on the brain to regulate energy balance but specific functions in many brain areas remain poorly understood. Among these, the preoptic area (POA) is well known to regulate core body temperature by controlling brown fat thermogenesis, and we have previously shown that glutamatergic, long-form leptin receptor (Lepr)-expressing neurons in the POA are stimulated by warm ambient temperature and suppress energy expenditure and food intake. Here we further investigate the role of POA leptin signaling in body weight regulation and its relationship to body temperature regulation in mice. We show that POA Lepr signaling modulates energy expenditure in response to internal energy state, and thus contributes to body weight homeostasis. However, POA leptin signaling is not involved in ambient temperature-dependent metabolic adaptations. Our study reveals a novel cell population through which leptin regulates body weight. © 2018, Yu et al.

Body fatness, body core temperature, and heat loss during moderate-intensity exercise.

PubMed

Limbaugh, Jayme D; Wimer, Gregory S; Long, Lynn H; Baird, William H

2013-11-01

This study examined the influence of body fatness on body core temperature and heat loss responses during moderate-intensity exercise. Nine men with lower body fat and eight men with higher body fat, matched for aerobic fitness, completed 1 h of recumbent cycling at the same absolute intensity in a warm environment (30 degrees C, 40% RH). Percent body fat was measured by hydrostatic weighing, using oxygen dilution to determine residual volume. Esophageal temperature (T(es)), mean skin temperature (T(sk)), and local sweat rate (m(sw)) were measured at rest and continuously during exercise while forearm blood flow (FBF) was measured at rest and every 10 min during exercise. The lower body fat and higher body fat groups were successfully matched for aerobic fitness, removing the influence of body fatness, given that V/O2(peak) was 50.72 +/- 7.34 and 50.43 +/- 5.01 ml x kg LBM(-1) x min(-1), respectively. When compared to lower body fat individuals, % body fat, body surface area (A(D)), and body mass were higher and A(D)/ mass was lower in higher body fat individuals. T(es), T(sk), FBF, m(sw), and the slope of m(sw):T(es) were not different between groups. Metabolic heat production was similar between the lower body fat (299.7 +/- 40.5 W x m(-2)) and higher body fat (288.1 +/- 30.6 W x m(-2)) subjects, respectively. Dry and evaporative heat loss, as well as heat storage during exercise, were not different between groups. These data suggest that there is no effect of body fatness on body core temperature or heat loss responses during moderate-intensity exercise in a warm environment.

Article comprising a garment or other textile structure for use in controlling body temperature

DOEpatents

Butzer, Melissa J.

2000-01-01

There is disclosed an article for use in cooling body temperature which comprises a garment having a coat and pant, with each having a body section adapted to receive a portion of the torso of the wearer and extensions from the body section to receive the wearer's limbs. The garment includes a system for circulating temperature controlling fluid from a suitable source through patches removably received in pockets in each of body section and extensions.

Does size matter? Comparison of body temperature and activity of free-living Arabian oryx (Oryx leucoryx) and the smaller Arabian sand gazelle (Gazella subgutturosa marica) in the Saudi desert.

PubMed

Hetem, Robyn Sheila; Strauss, Willem Maartin; Fick, Linda Gayle; Maloney, Shane Kevin; Meyer, Leith Carl Rodney; Shobrak, Mohammed; Fuller, Andrea; Mitchell, Duncan

2012-04-01

Heterothermy, a variability in body temperature beyond the normal limits of homeothermy, is widely viewed as a key adaptation of arid-adapted ungulates. However, desert ungulates with a small body mass, i.e. a relatively large surface area-to-volume ratio and a small thermal inertia, are theoretically less likely to employ adaptive heterothermy than are larger ungulates. We measured body temperature and activity patterns, using implanted data loggers, in free-ranging Arabian oryx (Oryx leucoryx, ±70 kg) and the smaller Arabian sand gazelle (Gazella subgutturosa marica, ±15 kg) inhabiting the same Arabian desert environment, at the same time. Compared to oryx, sand gazelle had higher mean daily body temperatures (F(1,6) = 47.3, P = 0.0005), higher minimum daily body temperatures (F(1,6) = 42.6, P = 0.0006) and higher maximum daily body temperatures (F(1,6) = 11.0, P = 0.02). Despite these differences, both species responded similarly to changes in environmental conditions. As predicted for adaptive heterothermy, maximum daily body temperature increased (F(1,6) = 84.0, P < 0.0001), minimum daily body temperature decreased (F(1,6) = 92.2, P < 0.0001), and daily body temperature amplitude increased (F(1,6) = 97.6, P < 0.0001) as conditions got progressively hotter and drier. There were no species differences in activity levels, however, both gazelle and oryx showed a biphasic or crepuscular rhythm during the warm wet season but shifted to a more nocturnal rhythm during the hot dry season. Activity was attenuated during the heat of the day at times when both species selected cool microclimates. These two species of Arabian ungulates employ heterothermy, cathemerality and shade seeking very similarly to survive the extreme, arid conditions of Arabian deserts, despite their size difference.

Body Temperature-Related Structural Transitions of Monotremal and Human Hemoglobin

PubMed Central

Digel, I.; Maggakis-Kelemen, Ch.; Zerlin, K. F.; Linder, Pt.; Kasischke, N.; Kayser, P.; Porst, D.; Temiz Artmann, A.; Artmann, G. M.

2006-01-01

In this study, temperature-related structural changes were investigated in human, duck-billed platypus (Ornithorhynchus anatinus, body temperature Tb = 31–33°C), and echidna (Tachyglossus aculeatus, body temperature Tb = 32–33°C) hemoglobin using circular dichroism spectroscopy and dynamic light scattering. The average hydrodynamic radius (Rh) and fractional (normalized) change in the ellipticity (Fobs) at 222 ± 2 nm of hemoglobin were measured. The temperature was varied stepwise from 25°C to 45°C. The existence of a structural transition of human hemoglobin at the critical temperature Tc between 36–37°C was previously shown by micropipette aspiration experiments, viscosimetry, and circular dichroism spectroscopy. Based on light-scattering measurements, this study proves the onset of molecular aggregation at Tc. In two different monotremal hemoglobins (echidna and platypus), the critical transition temperatures were found between 32–33°C, which are close to the species' body temperature Tb. The data suggest that the correlation of the structural transition's critical temperature Tc and the species' body temperature Tb is not mere coincidence but, instead, is a more widespread structural phenomenon possibly including many other proteins. PMID:16844747

Body temperature-related structural transitions of monotremal and human hemoglobin.

PubMed

Digel, I; Maggakis-Kelemen, Ch; Zerlin, K F; Linder, Pt; Kasischke, N; Kayser, P; Porst, D; Temiz Artmann, A; Artmann, G M

2006-10-15

In this study, temperature-related structural changes were investigated in human, duck-billed platypus (Ornithorhynchus anatinus, body temperature T(b) = 31-33 degrees C), and echidna (Tachyglossus aculeatus, body temperature T(b) = 32-33 degrees C) hemoglobin using circular dichroism spectroscopy and dynamic light scattering. The average hydrodynamic radius (R(h)) and fractional (normalized) change in the ellipticity (F(obs)) at 222 +/- 2 nm of hemoglobin were measured. The temperature was varied stepwise from 25 degrees C to 45 degrees C. The existence of a structural transition of human hemoglobin at the critical temperature T(c) between 36-37 degrees C was previously shown by micropipette aspiration experiments, viscosimetry, and circular dichroism spectroscopy. Based on light-scattering measurements, this study proves the onset of molecular aggregation at T(c). In two different monotremal hemoglobins (echidna and platypus), the critical transition temperatures were found between 32-33 degrees C, which are close to the species' body temperature T(b). The data suggest that the correlation of the structural transition's critical temperature T(c) and the species' body temperature T(b) is not mere coincidence but, instead, is a more widespread structural phenomenon possibly including many other proteins.

Short communication: calf body temperature following chemical disbudding with sedation: effects of milk allowance and supplemental heat.

PubMed

Vasseur, E; Rushen, J; de Passillé, A M

2014-01-01

The use of caustic paste combined with a sedative is one of the least painful methods for disbudding. It is recommended to disbud at as early as 5d of age. However, the sedative xylazine reportedly causes a decrease in core temperature. Furthermore, young calves do not thermoregulate efficiently. We investigated the effects of disbudding calves at 5d of age using caustic paste and xylazine sedation on body temperature, activity, and milk intake of 46 individually housed 5-d-old calves in a 2×2 factorial design, with milk fed at 4.5L/d (low-fed calves) versus 9L/d (high-fed calves), with or without a heat lamp. Body temperature, calf activity (standing time), and barn temperature were monitored continuously using automatic data loggers on the day of, before the day of, and the day after disbudding. All calves were injected intramuscularly with 0.25mL of 2mg/mL xylazine 20min before disbudding (dose: 0.12±0.003mL/kg of BW). We found that the body temperature of 5-d-old calves decreased immediately after the injection of the sedative xylazine. The body temperature of calves decreased 0.9±0.09°C and it took 3.8±0.32h to climb back to the preinjection body temperature. Calves that were fed the lower amount of milk, received a higher dose of xylazine (mL/kg BW), or were disbudded in a colder environment were more affected by body temperature variations (lower and longest decrease in body temperature and higher magnitude). Calf activity recovery followed the pattern of body temperature recovery. Milk allowance and supplemental heat did not help enhance recovery during the 6h following the procedure. The disbudding procedure did not affect milk intake but calves with less body temperature decrease or kept in a warmer environment drank more milk following disbudding. Low-fed calves were overall more affected by the procedure than high-fed calves during the disbudding day and the following day (greater decrease in body temperature and drank less in the colder environment). Providing a high-milk diet is a suitable option to help mitigate calf discomfort due to the disbudding procedure, whereas using a heat lamp does not seem to help, at least in a mildly cold winter. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Is higher body temperature beneficial in ischemic stroke patients with normal admission CT angiography of the cerebral arteries?

PubMed Central

Kvistad, Christopher Elnan; Khanevski, Andrej; Nacu, Aliona; Thomassen, Lars; Waje-Andreassen, Ulrike; Naess, Halvor

2014-01-01

Background Low body temperature is considered beneficial in ischemic stroke due to neuroprotective mechanisms, yet some studies suggest that higher temperatures may improve clot lysis and outcomes in stroke patients treated with tissue plasminogen activator (tPA). The effect of increased body temperature in stroke patients treated with tPA and with normal computed tomography angiography (CTA) on admission is unknown. We hypothesized a beneficial effect of higher body temperature in the absence of visible clots on CTA, possibly due to enhanced lysis of small, peripheral clots. Methods Patients with ischemic stroke admitted to our Stroke Unit between February 2006 and April 2013 were prospectively registered in a database (Bergen NORSTROKE Registry). Ischemic stroke patients treated with tPA with normal CTA of the cerebral arteries were included. Outcomes were assessed by the modified Rankin Scale (mRS) after 1 week. An excellent outcome was defined as mRS=0, and a favorable outcome as mRS=0–1. Results A total of 172 patients were included, of which 48 (27.9%) had an admission body temperature ≥37.0°C, and 124 (72.1%) had a body temperature <37.0°C. Body temperature ≥37.0°C was independently associated with excellent outcomes (odds ratio [OR]: 2.8; 95% confidence interval [CI]: 1.24–6.46; P=0.014) and favorable outcomes (OR: 2.8; 95% CI: 1.13–4.98; P=0.015) when adjusted for confounders. Conclusion We found an association between higher admission body temperature and improved outcome in tPA-treated stroke patients with normal admission CTA of the cerebral arteries. This may suggest a beneficial effect of higher body temperature on clot lysis in the absence of visible clots on CTA. PMID:24482573

Effects of incubation temperature on growth and performance of the veiled chameleon (Chamaeleo calyptratus).

PubMed

Andrews, Robin M

2008-10-01

I evaluated the effect of incubation temperature on phenotypes of the veiled chameleon, Chamaeleo calyptratus. I chose this species for study because its large clutch size (30-40 eggs or more) allows replication within clutches both within and among experimental treatments. The major research objectives were (1) to assess the effect of constant low, moderate, and high temperatures on embryonic development, (2) to determine whether the best incubation temperature for embryonic development also produced the "best" hatchlings, and (3) to determine how a change in incubation temperature during mid-development would affect phenotype. To meet these objectives, I established five experimental temperature regimes and determined egg survival and incubation length and measured body size and shape, selected body temperatures, and locomotory performance of lizards at regular intervals from hatching to 90 d, or just before sexual maturity. Incubation temperature affected the length of incubation, egg survival, and body mass, but did not affect sprint speed or selected body temperature although selected body temperature affected growth in mass independently of treatment and clutch. Incubation at moderate temperatures provided the best conditions for both embryonic and post-hatching development. The highest incubation temperatures were disruptive to development; eggs had high mortality, developmental rate was low, and hatchlings grew slowly. Changes in temperature during incubation increased the among-clutch variance in incubation length relative to that of constant temperature treatments. Copyright 2008 Wiley-Liss, Inc.

Thermal reference points as an index for monitoring body temperature in marine mammals.

PubMed

Melero, Mar; Rodríguez-Prieto, Víctor; Rubio-García, Ana; García-Párraga, Daniel; Sánchez-Vizcaíno, José Manuel

2015-09-04

Monitoring body temperature is essential in veterinary care as minor variations may indicate dysfunction. Rectal temperature is widely used as a proxy for body temperature, but measuring it requires special equipment, training or restraining, and it potentially stresses animals. Infrared thermography is an alternative that reduces handling stress, is safer for technicians and works well for untrained animals. This study analysed thermal reference points in five marine mammal species: bottlenose dolphin (Tursiops truncatus); beluga whale (Delphinapterus leucas); Patagonian sea lion (Otaria flavescens); harbour seal (Phoca vitulina); and Pacific walrus (Odobenus rosmarus divergens). The thermogram analysis revealed that the internal blowhole mucosa temperature is the most reliable indicator of body temperature in cetaceans. The temperatures taken during voluntary breathing with a camera held perpendicularly were practically identical to the rectal temperature in bottlenose dolphins and were only 1 °C lower than the rectal temperature in beluga whales. In pinnipeds, eye temperature appears the best parameter for temperature control. In these animals, the average times required for temperatures to stabilise after hauling out, and the average steady-state temperature values, differed according to species: Patagonian sea lions, 10 min, 31.13 °C; harbour seals, 10 min, 32.27 °C; Pacific walruses, 5 min, 29.93 °C. The best thermographic and most stable reference points for monitoring body temperature in marine mammals are open blowhole in cetaceans and eyes in pinnipeds.

Portable Body Temperature Conditioner

DTIC Science & Technology

2014-12-01

are homeothermic and require a narrow core body temperature range to maintain normal homeostasis. Currently, the most effective treatments for...for monitoring circulating water and patient body temperature . During breadboard testing the effectiveness of the air coil was found to be...blanket. Bath temperatures were set to 30°C, 15°C, and 10°C respectively. In order to develop a testing procedure for quantifying the effective

A simple and inexpensive system for controlling body temperature in small animal experiments using MRI and the effect of body temperature on the hepatic kinetics of Gd-EOB-DTPA.

PubMed

Murase, Kenya; Assanai, Purapan; Takata, Hiroshige; Saito, Shigeyoshi; Nishiura, Motoko

2013-12-01

The purpose of this study was to develop a simple and inexpensive system for controlling body temperature in small animal experiments using magnetic resonance imaging (MRI) and to investigate the effect of body temperature on the kinetic behavior of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) in the liver. In our temperature-control system, body temperature was controlled using a feedback-regulated heated or cooled air flow generated by two Futon dryers. The switches of the two Futon dryers were controlled using a digital temperature controller, in which the rectal temperature of a mouse measured by an optical fiber thermometer was used as the input. In experimental studies, male ICR mice aged 8weeks old were used and allocated into 5 groups (39-, 36-, 33-, 30-, and 27-degree groups, n=10), in which the body temperature was maintained at 39 °C, 36 °C, 33 °C, 30 °C, and 27 °C, respectively, using our system. The dynamic contrast-enhanced MRI (DCE-MRI) data were acquired with an MRI system for animal experiments equipped with a 1.5-Tesla permanent magnet, for approximately 43min, after the injection of Gd-EOB-DTPA into the tail vein. After correction of the image shift due to the temperature-dependent drift of the Larmor frequency using the gradient-based image registration method with robust estimation of displacement parameters, the kinetic behavior of Gd-EOB-DTPA was analyzed using an empirical mathematical model. With the use of this approach, the upper limit of the relative enhancement (A), the rates of contrast uptake (α) and washout (β), the parameter related to the slope of early uptake (q), the area under the curve (AUC), the maximum relative enhancement (REmax), the time to REmax (Tmax), and the elimination half-life of the contrast agent (T1/2) were calculated. The body temperature of mice could be controlled well by use of our system. Although there were no significant differences in α, AUC, and q among groups, there were significant differences in A, REmax, β, Tmax, and T1/2, indicating that body temperature significantly affects the kinetic behavior of Gd-EOB-DTPA in the liver. In conclusion, our system will be useful for controlling body temperature in small animal experiments using MRI. Because body temperature significantly affects the kinetic behavior of Gd-EOB-DTPA in the liver, the control of body temperature is essential and should be carefully considered when performing DCE-MRI studies in small animal experiments. © 2013.

Core Body and Skin Temperature in Type 1 Narcolepsy in Daily Life; Effects of Sodium Oxybate and Prediction of Sleep Attacks.

PubMed

van der Heide, Astrid; Werth, Esther; Donjacour, Claire E H M; Reijntjes, Robert H A M; Lammers, Gert Jan; Van Someren, Eus J W; Baumann, Christian R; Fronczek, Rolf

2016-11-01

Previous laboratory studies in narcolepsy patients showed altered core body and skin temperatures, which are hypothesised to be related to a disturbed sleep wake regulation. In this ambulatory study we assessed temperature profiles in normal daily life, and whether sleep attacks are heralded by changes in skin temperature. Furthermore, the effects of three months of treatment with sodium oxybate (SXB) were investigated. Twenty-five narcolepsy patients and 15 healthy controls were included. Core body, proximal and distal skin temperatures, and sleep-wake state were measured simultaneously for 24 hours in ambulatory patients. This procedure was repeated in 16 narcolepsy patients after at least 3 months of stable treatment with SXB. Increases in distal skin temperature and distal-to-proximal temperature gradient (DPG) strongly predicted daytime sleep attacks (P < 0.001). As compared to controls, patients had a higher proximal and distal skin temperature in the morning, and a lower distal skin temperature during the night (all P < 0.05). Furthermore, they had a higher core body temperature during the first part of the night (P < 0.05), which SXB decreased (F = 4.99, df = 1, P = 0.03) to a level similar to controls. SXB did not affect skin temperature. This ambulatory study demonstrates that daytime sleep attacks were preceded by clear changes in distal skin temperature and DPG. Furthermore, changes in core body and skin temperature in narcolepsy, previously only studied in laboratory settings, were partially confirmed. Treatment with SXB resulted in a normalisation of the core body temperature profile. Future studies should explore whether predictive temperature changes can be used to signal or even prevent sleep attacks. © 2016 Associated Professional Sleep Societies, LLC.

Seasonal variation in blood and muscle oxygen stores attributed to diving behavior, environmental temperature and pregnancy in a marine predator, the California sea lion.

PubMed

Villegas-Amtmann, Stella; Atkinson, Shannon; Paras-Garcia, Alberto; Costa, Daniel P

2012-08-01

Survival depends on an animal's ability to find and acquire prey. In diving vertebrates, this ability is directly related to their physiological capability (e.g. oxygen stores). We studied the seasonal variation in oxygen stores, body temperature and body condition in California sea lions (Zalophus californianus) (CSL) as a function of seasonal variation in temperature, primary productivity, diving behavior and reproductive stage. During summer, blood oxygen stores were significantly greater and muscle oxygen stores were significantly lower than in winter. Total oxygen stores, body condition and body temperature did not change between seasons but variations in body temperature were greater during summer. Changes in oxygen stores are partly attributed to diving behavior, temperature and pregnancy that could increase oxygen consumption. Blood and muscle oxygen stores appear to be influenced by reproductive state. Blood oxygen stores are more likely influenced by diving behavior and temperature than muscle oxygen stores. Copyright © 2012 Elsevier Inc. All rights reserved.

Protein deficiency: its effects on body temperature in health and disease states.

PubMed

Hoffman-Goetz, L; Kluger, M J

1979-07-01

Little is known about the effects of protein malnutrition on the ability to regulate body temperature during health and disease. To investigate this area, we placed young rabbits on a low-protein diet and recorded their body temperatures. There were no differences between the protein-deprived and control animals concerning their abilities to maintain constant body temperatures during exposure to low (5 C, 10 C) and thermoneutral ambient temperature (20 C). In a warm ambient temperature (30 C) the protein-deprived animals were actually better able to maintain a lower body temperature. Injections with heat killed bacteria led to little or no fever in the protein-deprived group. However, intravenous injections of endogenous pyrogen, a protein mediator of fever, resulted in fevers virtually identical to that attained in control animals. These data indicate that the attenuated febrile response to bacterial injection during protein deprivation may be due to a diminished production of endogenous pyrogen, and not to some alteration in the central nervous system sensitivity to pyrogens.

Compensation for environmental change by complementary shifts of thermal sensitivity and thermoregulatory behaviour in an ectotherm.

PubMed

Glanville, E J; Seebacher, F

2006-12-01

Thermoregulating animals are thought to have evolved a preferred body temperature at which thermally sensitive performance is optimised. Even during thermoregulation, however, many animals experience pronounced variability in body temperature, and may regulate to different body temperatures depending on environmental conditions. Here we test the hypothesis that there is a trade-off between regulating to lower body temperatures in cooler conditions and locomotory and metabolic performance. Animals (estuarine crocodiles, Crocodylus porosus) acclimated to cold (N=8) conditions had significantly lower maximum and mean daily body temperatures after 33 days than warm-acclimated animals (N=9), despite performing characteristic thermoregulatory behaviours. Concomitant with behavioural changes, maximum sustained swimming speed (U(crit)) shifted to the respective mean body temperatures during acclimation (cold=20 degrees C, warm=29 degrees C), but there was no difference in the maxima between acclimation groups. Mitochondrial oxygen consumption changed significantly during acclimation, and maximum respiratory control ratios coincided with mean body temperatures in liver, muscle and heart tissues. There were significant changes in the activities of regulatory metabolic enzymes (lactate dehydrogenase, citrate synthase, cytochrome c oxidase) and these were tissue specific. The extraordinary shift in behaviour and locomotory and metabolic performance shows that within individuals, behaviour and physiology covary to maximise performance in different environments.

Body temperature of trauma patients on admission to hospital: a comparison of anaesthetised and non-anaesthetised patients.

PubMed

Langhelle, Audun; Lockey, David; Harris, Tim; Davies, Gareth

2012-03-01

Hypothermia at hospital admission has been found to independently predict increased mortality in trauma patients. Objectives To establish if patients anaesthetised in the prehospital phase of care had a higher rate of hypothermia than non-anaesthetised patients on admission to hospital. Retrospective review of admission body temperature in 1292 consecutive prehospital trauma patients attended by a physician-led prehospital trauma service admitted to The Royal London Hospital between 1 July 2005 and 31 December 2008. 38% had a temperature recorded on admission. There was a significant difference in body temperature between the anaesthetised group (N=207) and the non-anaesthetised group (N=287): mean (SD) 35.0 (2.1) vs 36.2 (1.0)°C, respectively (p<0.001). No significant seasonal body temperature variation was demonstrated. This study confirmed that patients anaesthetised in the prehospital phase of care had a significantly lower admission body temperature. This has led to a change in the author's prehospital practice. Anaesthetised patients are now actively surface heated and have whole body insulation to prevent further heat loss in an attempt to conserve body temperature and improve outcome. This is an example of best in-hospital anaesthetic practice being carried out in the prehospital phase.

A comparison of temporal artery thermometers with internal blood monitors to measure body temperature during hemodialysis.

PubMed

Lunney, Meaghan; Tonelli, Bronwyn; Lewis, Rachel; Wiebe, Natasha; Thomas, Chandra; MacRae, Jennifer; Tonelli, Marcello

2018-06-14

Thermometers that measure core (internal) body temperature are the gold standard for monitoring temperature. Despite that most modern hemodialysis machines are equipped with an internal blood monitor that measures core body temperature, current practice is to use peripheral thermometers. A better understanding of how peripheral thermometers compare with the dialysis machine thermometer may help guide practice. The study followed a prospective cross-sectional design. Hemodialysis patients were recruited from 2 sites in Calgary, Alberta (April - June 2017). Body temperatures were obtained from peripheral (temporal artery) and dialysis machine thermometers concurrently. Paired t-tests, Bland-Altman plots, and quantile-quantile plots were used to compare measurements from the two devices and to explore potential factors affecting temperature in hemodialysis patients. The mean body temperature of 94 hemodialysis patients measured using the temporal artery thermometer (36.7 °C) was significantly different than the dialysis machine thermometer (36.4 °C); p < 0.001. The mean difference (0.27 °C) appeared to be consistent across average temperature (range: 35.8-37.3 °C). Temperature measured by the temporal artery thermometer was statistically and clinically higher than that measured by the dialysis machine thermometer. Using the dialysis machine to monitor body temperature may result in more accurate readings and is likely to reduce the purchasing and maintenance costs associated with manual temperature readings, as well as easing the workload for dialysis staff.

Increase in milk and body temperature of cows as a sign of embryo entry into the uterus.

PubMed

Gil, Z; Kural, J; Szarek, J; Wierzchoś, E

2001-09-01

The objective of the first stage of these studies was to investigate whether temperature increases in the milk and body of cows during the early period of pregnancy. We studied 94 pregnant and 116 nonpregnant cows, and the temperatures were measured daily beginning 24 days after insemination. In addition, progesterone levels in milk were measured twice (on Days 21 and 24 after insemination), and examinations per rectum were conducted to determine pregnancy. Data analysis showed that in almost 90% of the pregnant cows milk temperature increased by 0.64 degrees C some time between Days 5 and 12 after insemination. This increase in milk temperature was highly significant and corresponded with a 0.46 degrees C increase in body temperature. There was no increase in the milk or body temperature in nonpregnant cows. After discovering in the first stage that a high percentage of pregnant cows experienced both milk and body temperature increases, we focused our attention in the second stage of the study on the question of whether this increase in temperatures might be due to an immune response of the mother to the entry of the embryo into the uterus. In this stage we conducted three different experiments on another group of animals consisting of 309 cows and heifers. The experiments included analysis of progesterone, estradiol, cortisol and PGE2 levels in the blood serum of the cows and heifers; an estimation of the pyrogenic activity of PGE1, PGE2 and progesterone; and measurements of body temperature in the heifers before and after embryo transfer. The results of these experiments suggested that an increase in milk and body temperature could be an indicator of an immune response of the mother to the entry of the embryo into the uterus.

Effect of a heat and moisture exchanger on heat loss in isoflurane-anesthetized dogs undergoing single-limb orthopedic procedures.

PubMed

Hofmeister, Erik H; Brainard, Benjamin M; Braun, Christina; Figueiredo, Juliana P

2011-12-15

To determine whether a heat and moisture exchange device (HME) prevents a decrease in body temperature in isoflurane-anesthetized dogs undergoing orthopedic procedures. Blinded randomized controlled clinical trial. 60 privately owned dogs weighing at least 15 kg (33 lb). Dogs were randomly assigned to 1 of 3 treatment groups (n = 20/group): HME placed immediately after anesthetic induction with isoflurane, after transfer to the operating room, or not at all. The device consisted of a hygroscopic filter placed between the endotracheal tube and the Y piece of the anesthesia circuit. Each dog was positioned on a circulating warm water blanket and had a forced-air warming blanket placed over its body. Body temperature was monitored after transfer to the operating room with a probe placed in the thoracic aspect of the esophagus. Study groups did not differ significantly with respect to body weight, body condition score, reproductive status, breed, surgical procedure, preoperative sedative and opioid administration, anesthetic induction drug, local nerve block technique, or operating room assignment. There were no significant differences among groups in esophageal temperature variables, interval between anesthetic induction and surgery, surgery duration, anesthesia duration, or oxygen flow rate. However, the relationship between temperature delta and body weight was significant and relevant (R(2) = 0.23), as was the association between temperature nadir and body weight (R(2)= 0.10). As body weight increased, the temperature delta decreased and temperature nadir increased. No other significant relationships were identified. Inclusion of an HME in healthy dogs undergoing anesthesia for an elective orthopedic surgery did not facilitate maintenance of body temperature throughout the procedure.

Kinetic analysis of superparamagnetic iron oxide nanoparticles in the liver of body-temperature-controlled mice using dynamic susceptibility contrast magnetic resonance imaging and an empirical mathematical model.

PubMed

Murase, Kenya; Assanai, Purapan; Takata, Hiroshige; Matsumoto, Nozomi; Saito, Shigeyoshi; Nishiura, Motoko

2015-06-01

The purpose of this study was to develop a method for analyzing the kinetic behavior of superparamagnetic iron oxide nanoparticles (SPIONs) in the murine liver under control of body temperature using dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) and an empirical mathematical model (EMM). First, we investigated the influence of body temperature on the kinetic behavior of SPIONs in the liver by controlling body temperature using our temperature-control system. Second, we investigated the kinetic behavior of SPIONs in the liver when mice were injected with various doses of GdCl3, while keeping the body temperature at 36°C. Finally, we investigated it when mice were injected with various doses of zymosan, while keeping the body temperature at 36°C. We also investigated the effect of these substances on the number of Kupffer cells by immunohistochemical analysis using the specific surface antigen of Kupffer cells (CD68). To quantify the kinetic behavior of SPIONs in the liver, we calculated the upper limit of the relative enhancement (A), the rates of early contrast uptake (α) and washout or late contrast uptake (β), the parameter related to the slope of early uptake (q), the area under the curve (AUC), the maximum change of transverse relaxation rate (ΔR2) (ΔR2(max)), the time to ΔR2(max) (Tmax), and ΔR2 at the last time point (ΔR2(last)) from the time courses of ΔR2 using the EMM. The β and Tmax values significantly decreased and increased, respectively, with decreasing body temperature, suggesting that the phagocytic activity of Kupffer cells is significantly affected by body temperature. The AUC, ΔR2(max), and ΔR2(last) values decreased significantly with increasing dose of GdCl3, which was consistent with the change in the number of CD68-positive cells. They increased with increasing dose of zymosan, which was also consistent with the change in the number of CD68-positive cells. These results suggest that AUC, ΔR2(max), and ΔR2(last) reflect the number of Kupffer cells. In conclusion, we presented a method for analyzing the kinetic behavior of SPIONs in the liver using DSC-MRI and EMM, and investigated the influence of body temperature, GdCl3, and zymosan using body-temperature-controlled mice. The present study suggests that control of body temperature is essential for investigating the kinetic behavior of SPIONs in the liver and that our method will be applicable and useful for quantifying the responses of Kupffer cells to various drugs under control of body temperature. Copyright © 2015 Elsevier Inc. All rights reserved.

Temperature distribution in the human body under various conditions of induced hyperthermia

NASA Technical Reports Server (NTRS)

Korobko, O. V.; Perelman, T. L.; Fradkin, S. Z.

1977-01-01

A mathematical model based on heat balance equations was developed for studying temperature distribution in the human body under deep hyperthermia which is often induced in the treatment of malignant tumors. The model yields results which are in satisfactory agreement with experimental data. The distribution of temperature under various conditions of induced hyperthermia, i.e. as a function of water temperature and supply rate, is examined on the basis of temperature distribution curves in various body zones.

[Estimation of the time of death based on the measurements of the eye temperature in comparison with other body sites].

PubMed

Kaliszan, Michał; Hauser, Roman

2007-01-01

A systematic two-stage study was conducted in pigs to verify the models of postmortem body temperature decrease currently employed in forensic medicine. During the investigations, temperature recordings were performed in four body sites (eyeballs, orbit soft tissues, muscles and rectums). The results of the study support the possible use of the eyeball and also the orbit soft tissues as temperature measuring sites at the early phase after death; they have narrowed the significance of rectum temperature measurements to the late stage of postmortem body temperature decrease, shown insignificant correlations between the body weight and the temperature decrease rate constant and illustrated the functional increase of the time of death estimation error as the body cools, expressed in the distinct tendency to overestimate the calculated time of death as compared to the actual one. In the second stage of the experiment, a lack of a plateau phase was demonstrated, at least from 30 min post mortem. It was also found that in the very early post mortem period, the kinetics of cooling of all the body sites studied was better described by the two-exponential model than the single exponential one. The study also showed that the weak airflow present in the experimental conditions did not practically affect the course of cooling of the investigated body sites. Eyeball temperature measurements with an infra-red laser thermometer performed during the experiment proved to be of no use for determination of the time of death. The experiments allowed for defining the so far unreported value of physiological temperature of pig eyeball as 38 degrees C.

The thermal environment of the nest affects body and cell size in the solitary red mason bee (Osmia bicornis L.).

PubMed

Kierat, Justyna; Szentgyörgyi, Hajnalka; Czarnoleski, Marcin; Woyciechowski, Michał

2017-08-01

Many ectotherms grow larger at lower temperatures than at higher temperatures. This pattern, known as the temperature-size rule, is often accompanied by plastic changes in cell size, which can mechanistically explain the thermal dependence of body size. However, the theory predicts that thermal plasticity in cell size has adaptive value for ectotherms because there are different optimal cell-membrane-to-cell-volume ratios at different temperatures. At high temperatures, the demand for oxygen is high; therefore, a large membrane surface of small cells is beneficial because it allows high rates of oxygen transport into the cell. The metabolic costs of maintaining membranes become more important at low temperatures than at high temperatures, which favours large cells. In a field experiment, we manipulated the thermal conditions inside nests of the red mason bee, a solitary bee that does not regulate the temperature in its nests and whose larvae develop under ambient conditions. We assessed the effect of temperature on body mass and ommatidia size (our proxy of cell size). The body and cell sizes decreased in response to a higher mean temperature and greater temperature fluctuations. This finding is in accordance with predictions of the temperature-size rule and optimal cell size theory and suggests that both the mean temperature and the magnitude of temperature fluctuations are important for determining body and cell sizes. Additionally, we observed that males of the red mason bee tend to have larger ommatidia in relation to their body mass than females, which might play an important role during mating flight. Copyright © 2016 Elsevier Ltd. All rights reserved.

High temperature thrust chamber for spacecraft

NASA Technical Reports Server (NTRS)

Chazen, Melvin L. (Inventor); Mueller, Thomas J. (Inventor); Kruse, William D. (Inventor)

1998-01-01

A high temperature thrust chamber for spacecraft (20) is provided herein. The high temperature thrust chamber comprises a hollow body member (12) having an outer surface and an internal surface (16) defining the high temperature chamber (10). The body member (12) is made substantially of rhenium. An alloy (18) consisting of iridium and at least alloying metal selected of the group consisting of rhodium, platinum and palladium is deposited on at least a portion of the internal surface (16) of the body member (12). The iridium and the alloying metal are electrodeposited onto the body member (12). A HIP cycle is performed upon the body member (12) to cause the coating of iridium and the alloying metal to form the alloy (18) which protects the body member (12) from oxidation.

Effects of MDMA on body temperature in humans

PubMed Central

Liechti, Matthias E

2014-01-01

Hyperthermia is a severe complication associated with the recreational use of 3,4-methylenedioxymethamphetamine (MDMA, Ecstasy). In this review, the clinical laboratory studies that tested the effects of MDMA on body temperature are summarized. The mechanisms that underlie the hyperthermic effects of MDMA in humans and treatment of severe hyperthermia are presented. The data show that MDMA produces an acute and dose-dependent rise in core body temperature in healthy subjects. The increase in body temperature is in the range of 0.2-0.8°C and does not result in hyperpyrexia (>40°C) in a controlled laboratory setting. However, moderately hyperthermic body temperatures >38.0°C occur frequently at higher doses, even in the absence of physical activity and at room temperature. MDMA primarily releases serotonin and norepinephrine. Mechanistic clinical studies indicate that the MDMA-induced elevations in body temperature in humans partially depend on the MDMA-induced release of norepinephrine and involve enhanced metabolic heat generation and cutaneous vasoconstriction, resulting in impaired heat dissipation. The mediating role of serotonin is unclear. The management of sympathomimetic toxicity and associated hyperthermia mainly includes sedation with benzodiazepines and intravenous fluid replacement. Severe hyperthermia should primarily be treated with additional cooling and mechanical ventilation. PMID:27626046

Novel energy-saving strategies to multiple stressors in birds: the ultradian regulation of body temperature.

PubMed

Tattersall, Glenn J; Roussel, Damien; Voituron, Yann; Teulier, Loïc

2016-09-28

This study aimed to examine thermoregulatory responses in birds facing two commonly experienced stressors, cold and fasting. Logging devices allowing long-term and precise access to internal body temperature were placed within the gizzards of ducklings acclimated to cold (CA) (5°C) or thermoneutrality (TN) (25°C). The animals were then examined under three equal 4-day periods: ad libitum feeding, fasting and re-feeding. Through the analysis of daily as well as short-term, or ultradian, variations of body temperature, we showed that while ducklings at TN show only a modest decline in daily thermoregulatory parameters when fasted, they exhibit reduced surface temperatures from key sites of vascular heat exchange during fasting. The CA birds, on the other hand, significantly reduced their short-term variations of body temperature while increasing long-term variability when fasting. This phenomenon would allow the CA birds to reduce the energetic cost of body temperature maintenance under fasting. By analysing ultradian regulation of body temperature, we describe a means by which an endotherm appears to lower thermoregulatory costs in response to the combined stressors of cold and fasting. © 2016 The Author(s).

Physiology of transgenic mice with brown fat ablation: obesity is due to lowered body temperature.

PubMed

Klaus, S; Münzberg, H; Trüloff, C; Heldmaier, G

1998-02-01

We investigated the physiological basis for development of obesity in uncoupling protein-diphtheria toxin A chain (UCP-DTA) transgenic mice. In these mice the promoter of the brown adipose tissue (BAT)-specific UCP was used to drive expression of DTA, resulting in decreased BAT function and development of obesity and insulin resistance (Lowell, B. B., S. V. Susulic, A. Hamann, J. A. Lawitts, J. Himms-Hagen, B. B. Boyer, L. Kozak, and J. S. Flier. Nature 366: 740-742, 1994). In adult UCP-DTA mice, we measured food intake and food assimilation, locomotor activity, metabolic rate, and body temperature in comparison to control animals. No differences could be observed in food intake or assimilation and locomotor activity. Weight-specific metabolic rates at temperatures between 20 and 37 degrees C, however, were consistently lower in transgenic mice. Continuous telemetric recording of core body temperature showed that transgenic mice displayed a downshift in body temperature levels of approximately 0.9 degree C. In summary, we provide evidence that attenuated body temperature levels alone can be responsible for development of obesity and that BAT thermogenesis is a major determinant of body temperature levels in rodents.

Novel energy-saving strategies to multiple stressors in birds: the ultradian regulation of body temperature

PubMed Central

2016-01-01

This study aimed to examine thermoregulatory responses in birds facing two commonly experienced stressors, cold and fasting. Logging devices allowing long-term and precise access to internal body temperature were placed within the gizzards of ducklings acclimated to cold (CA) (5°C) or thermoneutrality (TN) (25°C). The animals were then examined under three equal 4-day periods: ad libitum feeding, fasting and re-feeding. Through the analysis of daily as well as short-term, or ultradian, variations of body temperature, we showed that while ducklings at TN show only a modest decline in daily thermoregulatory parameters when fasted, they exhibit reduced surface temperatures from key sites of vascular heat exchange during fasting. The CA birds, on the other hand, significantly reduced their short-term variations of body temperature while increasing long-term variability when fasting. This phenomenon would allow the CA birds to reduce the energetic cost of body temperature maintenance under fasting. By analysing ultradian regulation of body temperature, we describe a means by which an endotherm appears to lower thermoregulatory costs in response to the combined stressors of cold and fasting. PMID:27655770

Investigation of Factors Affecting Body Temperature Changes During Routine Clinical Head Magnetic Resonance Imaging

PubMed Central

Kim, Myeong Seong

2016-01-01

Background Pulsed radiofrequency (RF) magnetic fields, required to produce magnetic resonance imaging (MRI) signals from tissue during the MRI procedure have been shown to heat tissues. Objectives To investigate the relationship between body temperature rise and the RF power deposited during routine clinical MRI procedures, and to determine the correlation between this effect and the body’s physiological response. Patients and Methods We investigated 69 patients from the Korean national cancer center to identify the main factors that contribute to an increase in body temperature (external factors and the body’s response) during a clinical brain MRI. A routine protocol sequence of MRI scans (1.5 T and 3.0 T) was performed. The patient’s tympanic temperature was recorded before and immediately after the MRI procedure and compared with changes in variables related to the body’s physiological response to heat. Results Our investigation of the physiological response to RF heating indicated a link between increasing age and body temperature. A higher increase in body temperature was observed in older patients after a 3.0-T MRI (r = 0.07, P = 0.29 for 1.5-T MRI; r = 0.45, P = 0.002 for 3.0-T MRI). The relationship between age and body heat was related to the heart rate (HR) and changes in HR during the MRI procedure; a higher RF power combined with a reduction in HR resulted in an increase in body temperature. Conclusion A higher magnetic field strength and a decrease in the HR resulted in an increase in body temperature during the MRI procedure. PMID:27895872

Association between obesity and reduced body temperature in dogs.

PubMed

Piccione, G; Giudice, E; Fazio, F; Refinetti, R

2011-08-01

Industrialized nations are currently experiencing an obesity epidemic, the causes of which are not fully known. One possible mechanism of enhanced energy efficiency that has received almost no attention is a reduction in the metabolic cost of homeothermy, which could be achieved by a modest lowering of body core temperature. We evaluated the potential of this obesity-inducing mechanism in a canine model of the metabolic syndrome. We compared the rectal temperature of lean dogs and obese dogs by (a) conducting cross-sectional measurements in 287 dogs of many breeds varying greatly in body size, (b) conducting longitudinal measurements in individual dogs over 7-10 years and (c) tracking rectal temperature of lean and obese dogs at 3-h intervals for 48 consecutive hours in the laboratory. We found that larger dogs have lower rectal temperatures than smaller dogs and that, for the same body mass, obese dogs have lower rectal temperatures than lean dogs. The results were consistent in the cross-sectional, longitudinal and around-the-clock measurements. These findings document an association between obesity and reduced body temperature in dogs and support the hypothesis that obesity in this and other species of homeotherms may result from an increase in metabolic efficiency achieved by a regulated lowering of body temperature.

Primer on Preemies

MedlinePlus

... the body fat needed to maintain their body temperature, even when swaddled with blankets. So incubators or ... to the baby's skin senses his/her body temperature and regulates the heat. Nutrition and Growth Premature ...

Body temperature norms

MedlinePlus

Morrison SF. Regulation of body temperature. In: Boron WF, Boulpaep EL, eds. Medical Physiology . 3rd ed. Philadelphia, PA: Elsevier; 2017:chap 59. Sajadi MM, Mackowiak PA. Temperature regulation and the pathogenesis ...

Body temperature is elevated and linked to fatigue in relapsing-remitting multiple sclerosis, even without heat exposure

PubMed Central

Sumowski, James F.; Leavitt, Victoria M.

2014-01-01

Objective To investigate whether resting body temperature is elevated and linked to fatigue in patients with relapsing-remitting multiple sclerosis (RRMS). Design Cross-sectional study investigating (a) differences in resting body temperature across RRMS, SPMS, and healthy groups, and (b) the relationship between body temperature and fatigue in RRMS patients. Setting Climate-controlled laboratory (~22°C) within a non-profit medical rehabilitation research center. Participants Fifty patients with RRMS, 40 matched healthy controls, and 22 patients with secondary-progressive MS (SPMS). Intervention None. Main Outcome Measure(s) Body temperature was measured with an aural infrared thermometer (normal body temperature for this thermometer is 36.75°C), and differences were compared across RRMS, SPMS, and healthy persons. RRMS patients completed measures of general fatigue (Fatigue Severity Scale; FSS), as well as physical and cognitive fatigue (Modified Fatigue Impact Scale; MFIS). Results There was a large effect of group (p<.001, ηp2=.132) whereby body temperature was higher in RRMS patients (37.04°C±0.27) relative to healthy controls (36.83 ± 0.33; p = .009) and SPMS patients (36.75°C±0.39; p=.001). Warmer body temperature in RRMS patients was associated with worse general fatigue (FSS; rp=.315, p=.028) and physical fatigue (pMFIS; rp=.318, p=.026), but not cognitive fatigue (cMIFS; rp=−.017, p=.909). Conclusions These are the first-ever demonstrations that body temperature is elevated endogenously in RRMS patients, and linked to worse fatigue. We discuss these findings in the context of failed treatments for fatigue in RRMS, including several failed randomized controlled trials (RCTs) of stimulants (modafinil). In contrast, our findings may help explain how RCTs of cooling garments and antipyretics (aspirin) have effectively reduced MS fatigue, and encourage further research on cooling/antipyretic treatments of fatigue in RRMS. PMID:24561056

Core Body and Skin Temperature in Type 1 Narcolepsy in Daily Life; Effects of Sodium Oxybate and Prediction of Sleep Attacks

PubMed Central

van der Heide, Astrid; Werth, Esther; Donjacour, Claire E.H.M.; Reijntjes, Robert H.A.M.; Lammers, Gert Jan; Van Someren, Eus J.W.; Baumann, Christian R.; Fronczek, Rolf

2016-01-01

Study Objectives: Previous laboratory studies in narcolepsy patients showed altered core body and skin temperatures, which are hypothesised to be related to a disturbed sleep wake regulation. In this ambulatory study we assessed temperature profiles in normal daily life, and whether sleep attacks are heralded by changes in skin temperature. Furthermore, the effects of three months of treatment with sodium oxybate (SXB) were investigated. Methods: Twenty-five narcolepsy patients and 15 healthy controls were included. Core body, proximal and distal skin temperatures, and sleep-wake state were measured simultaneously for 24 hours in ambulatory patients. This procedure was repeated in 16 narcolepsy patients after at least 3 months of stable treatment with SXB. Results: Increases in distal skin temperature and distal-to-proximal temperature gradient (DPG) strongly predicted daytime sleep attacks (P < 0.001). As compared to controls, patients had a higher proximal and distal skin temperature in the morning, and a lower distal skin temperature during the night (all P < 0.05). Furthermore, they had a higher core body temperature during the first part of the night (P < 0.05), which SXB decreased (F = 4.99, df = 1, P = 0.03) to a level similar to controls. SXB did not affect skin temperature. Conclusions: This ambulatory study demonstrates that daytime sleep attacks were preceded by clear changes in distal skin temperature and DPG. Furthermore, changes in core body and skin temperature in narcolepsy, previously only studied in laboratory settings, were partially confirmed. Treatment with SXB resulted in a normalisation of the core body temperature profile. Future studies should explore whether predictive temperature changes can be used to signal or even prevent sleep attacks. Citation: van der Heide A, Werth E, Donjacour CE, Reijntjes RH, Lammers GJ, Van Someren EJ, Baumann CR, Fronczek R. Core body and skin temperature in type 1 narcolepsy in daily life; effects of sodium oxybate and prediction of sleep attacks. SLEEP 2016;39(11):1941–1949. PMID:27568803

Body temperature variability (Part 1): a review of the history of body temperature and its variability due to site selection, biological rhythms, fitness, and aging.

PubMed

Kelly, Greg

2006-12-01

Body temperature is a complex, non-linear data point, subject to many sources of internal and external variation. While these sources of variation significantly complicate interpretation of temperature data, disregarding knowledge in favor of oversimplifying complex issues would represent a significant departure from practicing evidence-based medicine. Part 1 of this review outlines the historical work of Wunderlich on temperature and the origins of the concept that a healthy normal temperature is 98.6 degrees F (37.0 degrees C). Wunderlich's findings and methodology are reviewed and his results are contrasted with findings from modern clinical thermometry. Endogenous sources of temperature variability, including variations caused by site of measurement, circadian, menstrual, and annual biological rhythms, fitness, and aging are discussed. Part 2 will review the effects of exogenous masking agents - external factors in the environment, diet, or lifestyle that can influence body temperature, as well as temperature findings in disease states.

Beyond the classic thermoneutral zone

PubMed Central

Kingma, Boris RM; Frijns, Arjan JH; Schellen, Lisje; van Marken Lichtenbelt, Wouter D

2014-01-01

The thermoneutral zone is defined as the range of ambient temperatures where the body can maintain its core temperature solely through regulating dry heat loss, i.e., skin blood flow. A living body can only maintain its core temperature when heat production and heat loss are balanced. That means that heat transport from body core to skin must equal heat transport from skin to the environment. This study focuses on what combinations of core and skin temperature satisfy the biophysical requirements of being in the thermoneutral zone for humans. Moreover, consequences are considered of changes in insulation and adding restrictions such as thermal comfort (i.e. driver for thermal behavior). A biophysical model was developed that calculates heat transport within a body, taking into account metabolic heat production, tissue insulation, and heat distribution by blood flow and equates that to heat loss to the environment, considering skin temperature, ambient temperature and other physical parameters. The biophysical analysis shows that the steady-state ambient temperature range associated with the thermoneutral zone does not guarantee that the body is in thermal balance at basal metabolic rate per se. Instead, depending on the combination of core temperature, mean skin temperature and ambient temperature, the body may require significant increases in heat production or heat loss to maintain stable core temperature. Therefore, the definition of the thermoneutral zone might need to be reformulated. Furthermore, after adding restrictions on skin temperature for thermal comfort, the ambient temperature range associated with thermal comfort is smaller than the thermoneutral zone. This, assuming animals seek thermal comfort, suggests that thermal behavior may be initiated already before the boundaries of the thermoneutral zone are reached. PMID:27583296

Optimal Body Temperature in Transitional ELBW Infants Using Heart Rate and Temperature as Indicators

PubMed Central

Knobel, Robin B.; Holditch-Davis, Diane; Schwartz, Todd A.

2013-01-01

Extremely low birth weight (ELBW) infants are vulnerable to cold stress after birth. Therefore, caregivers need to control body temperature optimally to minimize energy expenditure. Objective We explored body temperature in relationship to heart rate in ELBW infants during their first 12 hours to help identify the ideal set point for incubator control of body temperature. Design Within subject, multiple-case design. Setting A tertiary NICU in North Carolina. Participants 10 infants, born less than 29 weeks gestation and weighing 400-1000 grams. Methods Heart rate and abdominal body temperature were measured at 1-minute intervals for 12 hours. Heart rates were considered normal if they were between the 25th and 75th percentile for each infant. Results Abdominal temperatures were low throughout the 12-hour study period (mean 35.17° C-36.68° C). Seven of ten infants had significant correlations between abdominal temperature and heart rate. Heart rates above the 75th percentile were associated with low and high abdominal temperatures; heart rates less than the 25th percentile were associated with very low abdominal temperatures. The extent to which abdominal temperature was abnormally low was related the extent to which the heart rate trended away from normal in six of the ten infants. Optimal temperature control point that maximized normal heart rate observations for each infant was between 36.8° C and 37° C. Conclusions Hypothermia was associated with abnormal heart rates in transitional ELBW infants. We suggest nurses set incubator servo between 36.8° C and 36.9° C to optimally control body temperature for ELBW infants. PMID:20409098

Beyond the classic thermoneutral zone: Including thermal comfort.

PubMed

Kingma, Boris Rm; Frijns, Arjan Jh; Schellen, Lisje; van Marken Lichtenbelt, Wouter D

2014-01-01

The thermoneutral zone is defined as the range of ambient temperatures where the body can maintain its core temperature solely through regulating dry heat loss, i.e., skin blood flow. A living body can only maintain its core temperature when heat production and heat loss are balanced. That means that heat transport from body core to skin must equal heat transport from skin to the environment. This study focuses on what combinations of core and skin temperature satisfy the biophysical requirements of being in the thermoneutral zone for humans. Moreover, consequences are considered of changes in insulation and adding restrictions such as thermal comfort (i.e. driver for thermal behavior). A biophysical model was developed that calculates heat transport within a body, taking into account metabolic heat production, tissue insulation, and heat distribution by blood flow and equates that to heat loss to the environment, considering skin temperature, ambient temperature and other physical parameters. The biophysical analysis shows that the steady-state ambient temperature range associated with the thermoneutral zone does not guarantee that the body is in thermal balance at basal metabolic rate per se. Instead, depending on the combination of core temperature, mean skin temperature and ambient temperature, the body may require significant increases in heat production or heat loss to maintain stable core temperature. Therefore, the definition of the thermoneutral zone might need to be reformulated. Furthermore, after adding restrictions on skin temperature for thermal comfort, the ambient temperature range associated with thermal comfort is smaller than the thermoneutral zone. This, assuming animals seek thermal comfort, suggests that thermal behavior may be initiated already before the boundaries of the thermoneutral zone are reached.

Agreement between auricular and rectal measurements of body temperature in healthy cats.

PubMed

Sousa, Marlos G; Carareto, Roberta; Pereira-Junior, Valdo A; Aquino, Monally C C

2013-04-01

Measurement of body temperature is a routine part of the clinical assessment of a patient. However, this procedure may be time-consuming and stressful to most animals because the standard site of temperature acquisition remains the rectal mucosa. Although an increasing number of clinicians have been using auricular temperature to estimate core body temperature, evidence is still lacking regarding agreement between these two methods in cats. In this investigation, we evaluated the agreement between temperatures measured in the rectum and ear in 29 healthy cats over a 2-week period. Temperatures were measured in the rectum (using digital and mercury-in-glass thermometers) and ear once a day for 14 consecutive days, producing 406 temperature readings for each thermometer. Mean temperature and confidence intervals were similar between methods, and Bland-Altman plots showed small biases and narrow limits of agreement acceptable for clinical purposes. The interobserver variability was also checked, which indicated a strong correlation between two near-simultaneous temperature readings. Results are consistent with auricular thermometry being a reliable alternative to rectal thermometry for assessing core body temperature in healthy cats.

Prediction of brain tissue temperature using near-infrared spectroscopy.

PubMed

Holper, Lisa; Mitra, Subhabrata; Bale, Gemma; Robertson, Nicola; Tachtsidis, Ilias

2017-04-01

Broadband near-infrared spectroscopy (NIRS) can provide an endogenous indicator of tissue temperature based on the temperature dependence of the water absorption spectrum. We describe a first evaluation of the calibration and prediction of brain tissue temperature obtained during hypothermia in newborn piglets (animal dataset) and rewarming in newborn infants (human dataset) based on measured body (rectal) temperature. The calibration using partial least squares regression proved to be a reliable method to predict brain tissue temperature with respect to core body temperature in the wavelength interval of 720 to 880 nm with a strong mean predictive power of [Formula: see text] (animal dataset) and [Formula: see text] (human dataset). In addition, we applied regression receiver operating characteristic curves for the first time to evaluate the temperature prediction, which provided an overall mean error bias between NIRS predicted brain temperature and body temperature of [Formula: see text] (animal dataset) and [Formula: see text] (human dataset). We discuss main methodological aspects, particularly the well-known aspect of over- versus underestimation between brain and body temperature, which is relevant for potential clinical applications.

Observation of temperature trace, induced by changing of temperature inside the human body, on the human body skin using commercially available IR camera

NASA Astrophysics Data System (ADS)

Trofimov, Vyacheslav A.; Trofimov, Vladislav V.

2015-05-01

As it is well-known, application of the passive THz camera for the security problems is very promising way. It allows seeing concealed object without contact with a person and this camera is non-dangerous for a person. In previous papers, we demonstrate new possibility of the passive THz camera using for a temperature difference observing on the human skin if this difference is caused by different temperatures inside the body. For proof of validity of our statement we make the similar physical experiment using the IR camera. We show a possibility of temperature trace on human body skin, caused by changing of temperature inside the human body due to water drinking. We use as a computer code that is available for treatment of images captured by commercially available IR camera, manufactured by Flir Corp., as well as our developed computer code for computer processing of these images. Using both codes we demonstrate clearly changing of human body skin temperature induced by water drinking. Shown phenomena are very important for the detection of forbidden samples and substances concealed inside the human body using non-destructive control without X-rays using. Early we have demonstrated such possibility using THz radiation. Carried out experiments can be used for counter-terrorism problem solving. We developed original filters for computer processing of images captured by IR cameras. Their applications for computer processing of images results in a temperature resolution enhancing of cameras.

Eye surface temperature detects stress response in budgerigars (Melopsittacus undulatus).

PubMed

Ikkatai, Yuko; Watanabe, Shigeru

2015-08-05

Previous studies have suggested that stressors not only increase body core temperature but also body surface temperature in many animals. However, it remains unclear whether surface temperature could be used as an alternative to directly measure body core temperature, particularly in birds. We investigated whether surface temperature is perceived as a stress response in budgerigars. Budgerigars have been used as popular animal models to investigate various neural mechanisms such as visual perception, vocal learning, and imitation. Developing a new technique to understand the basic physiological mechanism would help neuroscience researchers. First, we found that cloacal temperature correlated with eye surface temperature. Second, eye surface temperature increased after handling stress. Our findings suggest that eye surface temperature is closely related to cloacal temperature and that the stress response can be measured by eye surface temperature in budgerigars.

Decrease of body temperature after aglepristone treatment in bitches.

PubMed

Corrada, Y; García, P; de la Sota, P E; Huzman, M; Landoni, M F; Gobello, C

2005-07-01

Body temperature responses and the timing of abortions were evaluated in pregnant bitches with the anti-progestin aglepristone. Fifteen purebred and crossbred, 25-45 days pregnant, were included in this study and seven untreated bitches at the same stage of pregnancy served as controls. Treated bitches were administered two applications of aglepristone (10 mg/kg SC) 24 h apart for pregnancy termination. Pregnancy termination was confirmed by ultrasonographic assessment. Body temperature was rectally measured three times a day for 6 days beginning 24 h before treatment or pregnancy diagnosis in the treated and control bitches, respectively. Additionally, serum progesterone concentrations were assessed at time points during the study in the treated bitches. Pregnancy was terminated in 14 treated bitches in a mean+/-S.E.M. of 4.3+/-0.7 days after treatment. Control bitches remained pregnant. In the treated bitches, but not in the controls, body temperature significantly decreased 24 h after the beginning of the treatments (P < 0.01) and then gradually returned to pre-treatment values. Correlation between the day of mean minimum body temperature and the day of pregnancy termination was low (0.07; > 0.05). Progesterone did not show significant change throughout the study. Body temperature does not seem to be a suitable variable to clinically monitor the aborting effect of aglepristone. Decrease of body temperature after aglepristone treatment could represent further evidence of its hypothalamic effects.

Effect of trunk-to-head bathing on physiological responses in newborns.

PubMed

So, Hyun-Sook; You, Mi-Ae; Mun, Je-Yung; Hwang, Myeong-Jin; Kim, Hyun-Kyung; Pyeon, Suk-Jin; Shin, Mi-Young; Chang, Bong-Hee

2014-01-01

To determine the effect of trunk-to-head bathing versus the traditional head-to-trunk bathing on newborns' body temperature, heart rate, and oxygen saturation. A prospective, two-group, quasi-experimental repeated measures design. A newborn nursery in an urban university hospital. Sixty-two healthy full-term newborns. Newborns were randomly assigned to two groups. The newborns in the experimental group were bathed from trunk to head; those in the control group were bathed from head to trunk. Measurements of body temperature, heart rate, and oxygen saturation were obtained at four time points: before the bath, immediately after the bath, 30 minutes after the bath, and 60 minutes after the bath. No significant differences in body temperature, heart rate, or oxygen saturation were observed between groups. However, body temperature was significantly different across measurement times, and there was a significant interaction between group and measurement time. The mean body temperature dropped 0.2°C after bathing in both groups, but the experimental group returned to their initial body temperature more rapidly than the control group. These findings suggest that newborns who were bathed from trunk to head and whose heads were wet for shorter periods of time benefited with a more rapid recovery of body temperature and decreased heat loss due to evaporation. © 2014 AWHONN, the Association of Women's Health, Obstetric and Neonatal Nurses.

Circadian body temperature variability is an indicator of poor prognosis in cardiomyopathic hamsters.

PubMed

Ahmed, Amany; Gondi, Sreedevi; Cox, Casey; Wang, Suwei; Stupin, Igor V; Shankar, K J; Munir, Shahzeb M; Sobash, Ed; Brewer, Alan; Ferguson, James J; Elayda, Macarthur A; Casscells, S Ward; Wilson, James M

2010-03-01

Low body temperature is an independent predictor of poor prognosis in patients with congestive heart failure. The cardiomyopathic hamster develops progressive biventricular dysfunction, resulting in heart failure death at 9 months to 1 year of life. Our goal was to use cardiomyopathic hamsters to examine the relationship between body temperature and heart failure decompensation and death. To this end, we implanted temperature and activity transducers with telemetry into the peritoneal space of 46 male Bio-TO-2 Syrian cardiomyopathic hamsters. Multiple techniques, including computing mean temperature, frequency domain analysis, and nonlinear analysis, were used to determine the most useful method for predicting poor prognosis. Data from 44 hamsters were included in our final analysis. We detected a decline in core body temperature in 98% of the hamsters 8+/-4 days before death (P < .001). We examined the dominant frequency of temperature variation (ie, the circadian rhythm) by using cosinor analysis, which revealed a significant decrease in the amplitude of the body temperature circadian rhythm 8 weeks before death (0.28 degrees C; 95% CI, 0.26-0.31) compared to baseline (0.36 degrees C; 95% CI, 0.34-0.39; P=.005). The decline in the circadian temperature variation preceded all other evidence of decompensation. We conclude that a decrease in the amplitude of the body temperature circadian rhythm precedes fatal decompensation in cardiomyopathic hamsters. Continuous temperature monitoring may be useful in predicting preclinical decompensation in patients with heart failure and in identifying opportunities for therapeutic intervention. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Changes in Body Temperature in Incomplete Spinal Cord Injury by Digital Infrared Thermographic Imaging

PubMed Central

Song, Yun-Gyu; Won, Yu Hui; Park, Sung-Hee; Ko, Myoung-Hwan

2015-01-01

Objective To investigate changes in the core temperature and body surface temperature in patients with incomplete spinal cord injuries (SCI). In incomplete SCI, the temperature change is difficult to see compared with complete spinal cord injuries. The goal of this study was to better understand thermal regulation in patients with incomplete SCI. Methods Fifty-six SCI patients were enrolled, and the control group consisted of 20 healthy persons. The spinal cord injuries were classified according to International Standards for Neurological Classification of Spinal Cord Injury. The patients were classified into two groups: upper (neurological injury level T6 or above) and lower (neurological injury level T7 or below) SCIs. Body core temperature was measured using an oral thermometer, and body surface temperature was measured using digital infrared thermographic imaging. Results Twenty-nine patients had upper spinal cord injuries, 27 patients had lower SCIs, and 20 persons served as the normal healthy persons. Comparing the skin temperatures of the three groups, the temperatures at the lower abdomen, anterior thigh and anterior tibia in the patients with upper SCIs were lower than those of the normal healthy persons and the patients with lower SCIs. No significant temperature differences were observed between the normal healthy persons and the patients with lower SCIs. Conclusion In our study, we found thermal dysregulation in patients with incomplete SCI. In particular, body surface temperature regulation was worse in upper SCIs than in lower injuries. Moreover, cord injury severity affected body surface temperature regulation in SCI patients. PMID:26605167

Predicting survival in critical patients by use of body temperature regularity measurement based on approximate entropy.

PubMed

Cuesta, D; Varela, M; Miró, P; Galdós, P; Abásolo, D; Hornero, R; Aboy, M

2007-07-01

Body temperature is a classical diagnostic tool for a number of diseases. However, it is usually employed as a plain binary classification function (febrile or not febrile), and therefore its diagnostic power has not been fully developed. In this paper, we describe how body temperature regularity can be used for diagnosis. Our proposed methodology is based on obtaining accurate long-term temperature recordings at high sampling frequencies and analyzing the temperature signal using a regularity metric (approximate entropy). In this study, we assessed our methodology using temperature registers acquired from patients with multiple organ failure admitted to an intensive care unit. Our results indicate there is a correlation between the patient's condition and the regularity of the body temperature. This finding enabled us to design a classifier for two outcomes (survival or death) and test it on a dataset including 36 subjects. The classifier achieved an accuracy of 72%.

GABA-A receptors in mPOAH simultaneously regulate sleep and body temperature in freely moving rats.

PubMed

Jha, S K; Yadav, V; Mallick, B N

2001-09-01

Sleep-wakefulness and body temperature are two circadian rhythmic biological phenomena. The role of GABAergic inputs in the medial preoptico-anterior hypothalamus (mPOAH) on simultaneous regulation of those phenomena was investigated in freely moving normally behaving rats. The GABA-A receptors were blocked by microinjecting picrotoxin, and the effects on electrophysiological parameters signifying sleep-wakefulness, rectal temperature and brain temperature were recorded simultaneously. The results suggest that, normally, GABA in the medial preoptic area acts through GABA-A receptor that induces sleep and prevents an excessive rise in body temperature. However, the results do not allow us to comment on the cause and effect relationship, if any, between changes in sleep-wakefulness and body temperature. The changes in brain and rectal temperatures showed a positive correlation, however, the former varied within a narrower range than that of the latter.

The impact of morning light intensity and environmental temperature on body temperatures and alertness.

PubMed

Te Kulve, Marije; Schlangen, Luc J M; Schellen, Lisje; Frijns, Arjan J H; van Marken Lichtenbelt, Wouter D

2017-06-01

Indoor temperature and light exposure are known to affect body temperature, productivity and alertness of building occupants. However, not much is known about the interaction between light and temperature exposure and the relationship between morning light induced alertness and its effect on body temperature. Light intensity and room temperature during morning office hours were investigated under strictly controlled conditions. In a randomized crossover study, two white light conditions (4000K, either bright 1200lx or dim 5lx) under three different room temperatures (26, 29 and 32°C) were investigated. A lower room temperature increased the core body temperature (CBT) and lowered skin temperature and the distal-proximal temperature gradient (DPG). Moreover, a lower room temperature reduced the subjective sleepiness and reaction time on an auditory psychomotor vigilance task (PVT), irrespective of the light condition. Interestingly, the morning bright light exposure did affect thermophysiological parameters, i.e. it decreased plasma cortisol, CBT and proximal skin temperature and increased the DPG, irrespective of the room temperature. During the bright light session, subjective sleepiness decreased irrespective of the room temperature. However, the change in sleepiness due to the light exposure was not related to these physiological changes. Copyright © 2017 Elsevier Inc. All rights reserved.

Sialon ceramic compositions and methods of fabrication

DOEpatents

O'Brien, Michael H.; Park, Blair H.

1994-01-01

A method of fabricating a SiAlON ceramic body includes: a) combining quantities of Si.sub.3 N.sub.4, Al.sub.2 O.sub.3 and CeO.sub.2 to produce a mixture; b) forming the mixture into a desired body shape; c) heating the body to a densification temperature of from about 1550.degree. C. to about 1850.degree. C.; c) maintaining the body at the densification temperature for a period of time effective to densify the body; d) cooling the densified body to a devitrification temperature of from about 1200.degree. C. to about 1400.degree. C.; and e) maintaining the densified body at the devitrification temperature for a period of time effective to produce a .beta.'-SiAlON crystalline phase in the body having elemental or compound form Ce incorporated in the .beta.'-SiAlON crystalline phase. Further, a SiAlON ceramic body comprises: a) an amorphous phase; and b) a crystalline phase, the crystalline phase comprising .beta.'-SiAlON having lattice substituted elemental or compound form Ce.

SiAlON ceramic compositions and methods of fabrication

DOEpatents

O'Brien, M.H.; Park, B.H.

1994-05-31

A method of fabricating a SiAlON ceramic body includes: (a) combining quantities of Si[sub 3]N[sub 4], Al[sub 2]O[sub 3] and CeO[sub 2] to produce a mixture; (b) forming the mixture into a desired body shape; (c) heating the body to a densification temperature of from about 1,550 C to about 1,850 C; (d) maintaining the body at the densification temperature for a period of time effective to densify the body; (e) cooling the densified body to a devitrification temperature of from about 1,200 C to about 1,400 C; and (f) maintaining the densified body at the devitrification temperature for a period of time effective to produce a [beta][prime]-SiAlON crystalline phase in the body having elemental or compound form Ce incorporated in the [beta][prime]-SiAlON crystalline phase. Further, a SiAlON ceramic body comprises: (a) an amorphous phase; and (b) a crystalline phase, the crystalline phase comprising [beta][prime]-SiAlON having lattice substituted elemental or compound form Ce.

Evaluating pen-day interactions in body temperature bilogistic mixed model for handling of feedlot heifers during heat stress

USDA-ARS?s Scientific Manuscript database

Daily activities consume the energy of heifers, subsequently causing an elevation of body temperature, depending on the ambient conditions. A better understanding of the dynamics of body temperature (Tb) would be helpful when deciding how to process and handle heifers. It would also lead to specific...

Acute dim light at night increases body mass, alters metabolism, and shifts core body temperature circadian rhythms.

PubMed

Borniger, Jeremy C; Maurya, Santosh K; Periasamy, Muthu; Nelson, Randy J

2014-10-01

The circadian system is primarily entrained by the ambient light environment and is fundamentally linked to metabolism. Mounting evidence suggests a causal relationship among aberrant light exposure, shift work, and metabolic disease. Previous research has demonstrated deleterious metabolic phenotypes elicited by chronic (>4 weeks) exposure to dim light at night (DLAN) (∼ 5 lux). However, the metabolic effects of short-term (<2 weeks) exposure to DLAN are unspecified. We hypothesized that metabolic alterations would arise in response to just 2 weeks of DLAN. Specifically, we predicted that mice exposed to dim light would gain more body mass, alter whole body metabolism, and display altered body temperature (Tb) and activity rhythms compared to mice maintained in dark nights. Our data largely support these predictions; DLAN mice gained significantly more mass, reduced whole body energy expenditure, increased carbohydrate over fat oxidation, and altered temperature circadian rhythms. Importantly, these alterations occurred despite similar activity locomotor levels (and rhythms) and total food intake between groups. Peripheral clocks are potently entrained by body temperature rhythms, and the deregulation of body temperature we observed may contribute to metabolic problems due to "internal desynchrony" between the central circadian oscillator and temperature sensitive peripheral clocks. We conclude that even relatively short-term exposure to low levels of nighttime light can influence metabolism to increase mass gain.

Body water balance and body temperature in vasopressin V1b receptor knockout mice.

PubMed

Daikoku, R; Kunitake, T; Kato, K; Tanoue, A; Tsujimoto, G; Kannan, H

2007-10-30

In an attempt to determine whether there is a specific vasopressin receptor (V(1b)) subtype involved in the regulation of body water balance and temperature, vasopressin V(1b) receptor knockout mice were used. Daily drinking behavior and renal excretory function were examined in V(1b)-deficient (V(1b)(-/-)) and control (V(1b)(+/+)) mice under the basal and stress-induced condition. In addition, body temperature and locomotor activity were measured with a biotelemetry system. The baseline daily water intake and urine volume were larger in V(1b)(-/-) mice than in V(1b)(+/+) mice. V(1b)(-/-) mice (V(1b)(-/-)) had significantly higher locomotor activity than wild-type, whereas the body temperature and oxygen consumption were lower in V(1b)(-/-) than in the V(1b)(+/+) mice. Next, the V(1b)(-/-) and V(1b)(+/+) mice were subjected to water deprivation for 48 hr. Under this condition, their body temperature decreased with the time course, which was significantly larger for V(1b)(-/-) than for V(1b)(+/+) mice. Central vasopressin has been reported to elicit drinking behavior and antipyretic action, and the V(1b) receptor has been reported to be located in the kidney. Thus, the findings suggest that the V(1b) receptor may be, at least in part, involved in body water balance and body temperature regulation.

FDTD analysis of human body-core temperature elevation due to RF far-field energy prescribed in the ICNIRP guidelines.

PubMed

Hirata, Akimasa; Asano, Takayuki; Fujiwara, Osamu

2007-08-21

This study investigated the relationship between the specific absorption rate and temperature elevation in an anatomically-based model named NORMAN for exposure to radio-frequency far fields in the ICNIRP guidelines (1998 Health Phys. 74 494-522). The finite-difference time-domain method is used for analyzing the electromagnetic absorption and temperature elevation in NORMAN. In order to consider the variability of human thermoregulation, parameters for sweating are derived and incorporated into a conventional sweating formula. First, we investigated the effect of blood temperature variation modeling on body-core temperature. The computational results show that the modeling of blood temperature variation was the dominant factor influencing the body-core temperature. This is because the temperature in the inner tissues is elevated via the circulation of blood whose temperature was elevated due to EM absorption. Even at different frequencies, the body-core temperature elevation at an identical whole-body average specific absorption rate (SAR) was almost the same, suggesting the effectiveness of the whole-body average SAR as a measure in the ICNIRP guidelines. Next, we discussed the effect of sweating on the temperature elevation and thermal time constant of blood. The variability of temperature elevation caused by the sweating rate was found to be 30%. The blood temperature elevation at the basic restriction in the ICNIRP guidelines of 0.4 W kg(-1) is 0.25 degrees C even for a low sweating rate. The thermal time constant of blood temperature elevation was 23 min and 52 min for a man with a lower and a higher sweating rate, respectively, which is longer than the average time of the SAR in the ICNIRP guidelines. Thus, the whole-body average SAR required for blood temperature elevation of 1 degrees C was 4.5 W kg(-1) in the model of a human with the lower sweating coefficients for 60 min exposure. From a comparison of this value with the basic restriction in the ICNIRP guidelines of 0.4 W kg(-1), the safety factor was 11.

Evaluating thermoregulation in reptiles: the fallacy of the inappropriately applied method.

PubMed

Seebacher, Frank; Shine, Richard

2004-01-01

Given the importance of heat in most biological processes, studies on thermoregulation have played a major role in understanding the ecology of ectothermic vertebrates. It is, however, difficult to assess whether body temperature is actually regulated, and several techniques have been developed that allow an objective assessment of thermoregulation. Almost all recent studies on reptiles follow a single methodology that, when used correctly, facilitates comparisons between species, climates, and so on. However, the use of operative temperatures in this methodology assumes zero heat capacity of the study animals and is, therefore, appropriate for small animals only. Operative temperatures represent potentially available body temperatures accurately for small animals but can substantially overestimate the ranges of body temperature available to larger animals whose slower rates of heating and cooling mean that they cannot reach equilibrium if they encounter operative temperatures that change rapidly through either space or time. This error may lead to serious misinterpretations of field data. We derive correction factors specific for body mass and rate of movement that can be used to estimate body temperature null distributions of larger reptiles, thereby overcoming this methodological problem.

Whole-body cryostimulation increases parasympathetic outflow and decreases core body temperature.

PubMed

Zalewski, Pawel; Bitner, Anna; Słomko, Joanna; Szrajda, Justyna; Klawe, Jacek J; Tafil-Klawe, Malgorzata; Newton, Julia L

2014-10-01

The cardiovascular, autonomic and thermal response to whole-body cryostimulation exposure are not completely known. Thus the aim of this study was to evaluate objectively and noninvasively autonomic and thermal reactions observed after short exposure to very low temperatures. We examined 25 healthy men with mean age 30.1 ± 3.7 years and comparable anthropomorphical characteristic. Each subject was exposed to cryotherapeutic temperatures in a cryogenic chamber for 3 min (approx. -120 °C). The cardiovascular and autonomic parameters were measured noninvasively with Task Force Monitor. The changes in core body temperature were determined with the Vital Sense telemetric measurement system. Results show that 3 min to cryotherapeutic temperatures causes significant changes in autonomic balance which are induced by peripheral and central blood volume changes. Cryostimulation also induced changes in core body temperature, maximum drop of core temperature was observed 50-60 min after the stimulation. Autonomic and thermal reactions to cryostimulation were observed up to 6 h after the exposure and were not harmful for examined subjects. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of a whole-body spandex garment on rectal temperature and oxygen consumption in healthy dogs.

PubMed

Reimer, S Brent; Schulz, Kurt S; Mason, David R; Jones, James H

2004-01-01

To determine whether a full-body spandex garment would alter rectal temperatures of healthy dogs at rest in cool and warm environments. Prospective study. 10 healthy dogs. Each dog was evaluated at a low (20 degrees to 25 degrees C [68 degrees to 77 degrees F]) or high (30 degrees to 35 degrees C [86 degrees to 95 degrees F]) ambient temperature while wearing or not wearing a commercially available whole-body spandex garment designed for dogs. Oxygen consumption was measured by placing dogs in a flow-through indirect calorimeter for 90 to 120 minutes. Rectal temperature was measured before dogs were placed in the calorimeter and after they were removed. Rectal temperature increased significantly more at the higher ambient temperature than at the lower temperature and when dogs were not wearing the garment than when they were wearing it. The specific rate of oxygen consumption was significantly higher at the lower ambient temperature than at the higher temperature. Results suggest that wearing a snug spandex body garment does not increase the possibility that dogs will overheat while in moderate ambient temperatures. Instead, wearing such a garment may enable dogs to better maintain body temperature during moderate heat loading. These results suggest that such garments might be used for purposes such as wound or suture protection without causing dogs to overheat.

Protracted effects of chronic stress on serotonin-dependent thermoregulation.

PubMed

Natarajan, Reka; Northrop, Nicole A; Yamamoto, Bryan K

2015-01-01

Chronic stress is known to affect serotonin (5HT) neurotransmission in the brain and to alter body temperature. The body temperature is controlled in part, by the medial preoptic area (mPOA) of the hypothalamus. To investigate the effect of chronic stress on 5HT and how it affects body temperature regulation, we examined whether exposure to a chronic unpredictable stress (CUS) paradigm produces long-term alterations in thermoregulatory function of the mPOA through decreased 5HT neurotransmission. Adult male Sprague-Dawley rats underwent 21 d of CUS. Four days after the last stress exposure, basal body temperature in the home cage and body temperature in a cold room maintained at 10 °C were recorded. The CUS rats had significantly higher subcutaneous basal body temperature at 13:00 h compared to unstressed (NoStress) rats. Whereas the NoStress rats were able to significantly elevate body temperature from basal levels at 30 and 60 min of exposure to the cold room, the CUS rats showed a hypothermic response to the cold. Treatment during CUS with metyrapone, a corticosterone synthesis inhibitor, blocked stress-induced decrease in body temperature in response to the cold challenge. CUS also decreased 5HT transporter protein immunoreactivity in the mPOA and 5HT2A/C agonist injection into the mPOA after CUS exposure caused stressed rats to exhibit a sensitized hyperthermic response to cold. These results indicate that the CUS induced changes to the 5HTergic system alter mPOA function in thermoregulation. These findings help us to explain the mechanisms underlying chronic stress-induced disorders such as chronic fatigue syndrome wherein long lasting thermoregulatory deficits are observed.

Protracted effects of chronic stress on serotonin dependent thermoregulation

PubMed Central

Natarajan, Reka; Northrop, Nicole A.; Yamamoto, Bryan K.

2016-01-01

Chronic stress is known to affect serotonin (5HT) neurotransmission in the brain and to alter body temperature. Body temperature is controlled in part, by the medial preoptic area of the hypothalamus (mPOA). To investigate the effect of chronic stress on 5HT and how it affects body temperature regulation, we examined whether exposure to a chronic unpredictable stress paradigm (CUS) produces long-term alterations in thermoregulatory function of the mPOA through decreased 5HT neurotransmission. Adult male Sprague-Dawley rats underwent 21 days of CUS. Four days after last stress exposure, basal body temperature in the home cage and body temperature in a cold room maintained at 10°C were recorded. CUS rats had significantly higher subcutaneous basal body temperature at 13:00 h compared to unstressed (NoStress) rats. Whereas the NoStress rats were able to significantly elevate body temperature from basal levels at 30 and 60 min of exposure to the cold room, the CUS rats showed a hypothermic response to the cold. Treatment during CUS with metyrapone, a corticosterone synthesis inhibitor, blocked stress-induced decrease in body temperature in response to the cold challenge. CUS also decreased 5HT transporter protein immunoreactivity in the mPOA and 5HT2A/C agonist injection into the mPOA after CUS exposure caused stressed rats to exhibit a sensitized hyperthermic response to cold. These results indicate that CUS induced changes to the 5HTergic system alters mPOA function in thermoregulation. These findings help explain mechanisms underlying chronic stress induced disorders such as chronic fatigue syndrome wherein long lasting thermoregulatory deficits are observed. PMID:26414686

Bison body size and climate change.

PubMed

Martin, Jeff M; Mead, Jim I; Barboza, Perry S

2018-05-01

The relationship between body size and temperature of mammals is poorly resolved, especially for large keystone species such as bison ( Bison bison ). Bison are well represented in the fossil record across North America, which provides an opportunity to relate body size to climate within a species. We measured the length of a leg bone (calcaneal tuber, DstL) in 849 specimens from 60 localities that were dated by stratigraphy and 14 C decay. We estimated body mass ( M ) as M  = (DstL/11.49) 3 . Average annual temperature was estimated from δ 18 O values in the ice cores from Greenland. Calcaneal tuber length of  Bison  declined over the last 40,000 years, that is, average body mass was 37% larger (910 ± 50 kg) than today (665 ± 21 kg). Average annual temperature has warmed by 6°C since the Last Glacial Maximum (~24-18 kya) and is predicted to further increase by 4°C by the end of the 21st century. If body size continues to linearly respond to global temperature, Bison body mass will likely decline by an additional 46%, to 357 ± 54 kg, with an increase of 4°C globally. The rate of mass loss is 41 ± 10 kg per°C increase in global temperature. Changes in body size of Bison may be a result of migration, disease, or human harvest but those effects are likely to be local and short-term and not likely to persist over the long time scale of the fossil record. The strong correspondence between body size of bison and air temperature is more likely the result of persistent effects on the ability to grow and the consequences of sustaining a large body mass in a warming environment. Continuing rises in global temperature will likely depress body sizes of bison, and perhaps other large grazers, without human intervention.

Dogs with macroadenomas have lower body temperature and heart rate than dogs with microadenomas.

PubMed

Benchekroun, Ghita; Desquilbet, Loic; Herrtage, Michael E; Jeffery, Nick D; Rosenberg, Dan; Granger, Nicolas

2017-09-01

Pituitary macroadenomas compress the hypothalamus, which partly regulates heart rate and body temperature. The aim of this study was to investigate whether heart rate and/or body temperature could aid in clinically differentiating dogs with macroadenomas from dogs with microadenomas (i.e. small non-compressive pituitary mass). Two groups of dogs diagnosed with pituitary-dependent hyperadrenocorticism (i.e. Cushing's disease) were included. Heart rate and body temperature were collected on initial presentation before any procedure. Dogs with macroadenoma had a significantly lower heart rate and body temperature (P<0.01) compared to dogs with microadenoma. We suggest that the combined cut-off values of 84 beats per minutes and 38.3°C in dogs with Cushing's disease, especially with vague neurological signs (nine of 12 dogs=75%), might help to suspect the presence of a macroadenoma. Copyright © 2017 Elsevier Ltd. All rights reserved.

Occupational heat strain in a hot underground metal mine.

PubMed

Lutz, Eric A; Reed, Rustin J; Turner, Dylan; Littau, Sally R

2014-04-01

In a hot underground metal mine, this study evaluated the relationship between job task, physical body type, work shift, and heat strain. Thirty-one miners were evaluated during 98 shifts while performing deep shaft-sinking tasks. Continuous core body temperature, heart rate, pre- and postshift urine specific gravity (USG), and body mass index were measured. Cutting and welding tasks were associated with significantly (P < 0.05) increased core body temperature, maximum heart rate, and increased postshift urine specific gravity. Miners in the obese level II and III body mass index categories, as well as those working night shift, had lower core body temperatures (P < 0.05). This study confirms that job task, body type, and shift are risk factors for heat strain.

Reliability issues in human brain temperature measurement

PubMed Central

2009-01-01

Introduction The influence of brain temperature on clinical outcome after severe brain trauma is currently poorly understood. When brain temperature is measured directly, different values between the inside and outside of the head can occur. It is not yet clear if these differences are 'real' or due to measurement error. Methods The aim of this study was to assess the performance and measurement uncertainty of body and brain temperature sensors currently in use in neurocritical care. Two organic fixed-point, ultra stable temperature sources were used as the temperature references. Two different types of brain sensor (brain type 1 and brain type 2) and one body type sensor were tested under rigorous laboratory conditions and at the bedside. Measurement uncertainty was calculated using internationally recognised methods. Results Average differences between the 26°C reference temperature source and the clinical temperature sensors were +0.11°C (brain type 1), +0.24°C (brain type 2) and -0.15°C (body type), respectively. For the 36°C temperature reference source, average differences between the reference source and clinical thermometers were -0.02°C, +0.09°C and -0.03°C for brain type 1, brain type 2 and body type sensor, respectively. Repeat calibrations the following day confirmed that these results were within the calculated uncertainties. The results of the immersion tests revealed that the reading of the body type sensor was sensitive to position, with differences in temperature of -0.5°C to -1.4°C observed on withdrawing the thermometer from the base of the isothermal environment by 4 cm and 8 cm, respectively. Taking into account all the factors tested during the calibration experiments, the measurement uncertainty of the clinical sensors against the (nominal) 26°C and 36°C temperature reference sources for the brain type 1, brain type 2 and body type sensors were ± 0.18°C, ± 0.10°C and ± 0.12°C respectively. Conclusions The results show that brain temperature sensors are fundamentally accurate and the measurements are precise to within 0.1 to 0.2°C. Subtle dissociation between brain and body temperature in excess of 0.1 to 0.2°C is likely to be real. Body temperature sensors need to be secured in position to ensure that measurements are reliable. PMID:19573241

Infrared thermal imaging as a method to evaluate heat loss in newborn lambs.

PubMed

Labeur, L; Villiers, G; Small, A H; Hinch, G N; Schmoelzl, S

2017-12-01

Thermal imaging technology has been identified as a potential method for non-invasive study of thermogenesis in the neonatal lamb. In comparison to measurement of the core body temperature, infrared thermography may observe thermal loss and thermogenesis linked to subcutaneous brown fat depots. This study aimed to identify a suitable method to measure heat loss in the neonatal lamb under a cold challenge. During late pregnancy (day 125), ewes were subjected to either shearing (n=15) or mock handling (sham-shorn for 2min mimicking the shearing movements) (n=15). Previous studies have shown an increase in brown adipose tissue deposition in lambs born to ewes shorn during pregnancy and we hypothesized that the shearing treatment would impact thermoregulatory capacities in newborn lambs. Lambs born to control ewes (n=14; CONTROL) and shorn ewes (n=13; SHORN) were subjected to a cold challenge of 1h duration at 4h after birth. During the cold challenge, thermography images were taken every 10min, from above, at a fixed distance from the dorsal midline. On each image, four fixed-size areas were identified (shoulder, mid loin, hips and rump) and the average and maximum temperatures of each recorded. In all lambs, body surface temperature decreased over time. Overall the SHORN lambs appeared to maintain body surface temperature better than CONTROL lambs, while CONTROL lambs appeared to have higher core temperature. At 30min post cold challenge SHORN lambs tended to have higher body surface temperatures than lambs (P=0.0474). Both average and maximum temperatures were highest at the hips. Average temperature was lowest at the shoulder (P<0.05), while maximum temperatures were lowest at both shoulder and rump (P<0.005). These results indicate that lambs born to shorn ewes maintained their radiated body surface temperature better than CONTROL lambs. In conjunction with core temperature changes under cold challenge, this insight will allow us to understand whether increased body surface temperature contributes to increased overall heat loss or whether increased body surface temperature is indeed a mechanism contributing to maintenance of core body temperature under cold challenge conditions. This study has confirmed the utility of infrared thermography images to capture and identify different levels of thermoregulatory capacity in newborn lambs. Copyright © 2017 Elsevier Ltd. All rights reserved.

3D Printed "Earable" Smart Devices for Real-Time Detection of Core Body Temperature.

PubMed

Ota, Hiroki; Chao, Minghan; Gao, Yuji; Wu, Eric; Tai, Li-Chia; Chen, Kevin; Matsuoka, Yasutomo; Iwai, Kosuke; Fahad, Hossain M; Gao, Wei; Nyein, Hnin Yin Yin; Lin, Liwei; Javey, Ali

2017-07-28

Real-time detection of basic physiological parameters such as blood pressure and heart rate is an important target in wearable smart devices for healthcare. Among these, the core body temperature is one of the most important basic medical indicators of fever, insomnia, fatigue, metabolic functionality, and depression. However, traditional wearable temperature sensors are based upon the measurement of skin temperature, which can vary dramatically from the true core body temperature. Here, we demonstrate a three-dimensional (3D) printed wearable "earable" smart device that is designed to be worn on the ear to track core body temperature from the tympanic membrane (i.e., ear drum) based on an infrared sensor. The device is fully integrated with data processing circuits and a wireless module for standalone functionality. Using this smart earable device, we demonstrate that the core body temperature can be accurately monitored regardless of the environment and activity of the user. In addition, a microphone and actuator are also integrated so that the device can also function as a bone conduction hearing aid. Using 3D printing as the fabrication method enables the device to be customized for the wearer for more personalized healthcare. This smart device provides an important advance in realizing personalized health care by enabling real-time monitoring of one of the most important medical parameters, core body temperature, employed in preliminary medical screening tests.

Is Oral Temperature an Accurate Measurement of Deep Body Temperature? A Systematic Review

PubMed Central

Mazerolle, Stephanie M.; Ganio, Matthew S.; Casa, Douglas J.; Vingren, Jakob; Klau, Jennifer

2011-01-01

Context: Oral temperature might not be a valid method to assess core body temperature. However, many clinicians, including athletic trainers, use it rather than criterion standard methods, such as rectal thermometry. Objective: To critically evaluate original research addressing the validity of using oral temperature as a measurement of core body temperature during periods of rest and changing core temperature. Data Sources: In July 2010, we searched the electronic databases PubMed, Scopus, Cumulative Index to Nursing and Allied Health Literature (CINAHL), SPORTDiscus, Academic Search Premier, and the Cochrane Library for the following concepts: core body temperature, oral, and thermometers. Controlled vocabulary was used, when available, as well as key words and variations of those key words. The search was limited to articles focusing on temperature readings and studies involving human participants. Data Synthesis: Original research was reviewed using the Physiotherapy Evidence Database (PEDro). Sixteen studies met the inclusion criteria and subsequently were evaluated by 2 independent reviewers. All 16 were included in the review because they met the minimal PEDro score of 4 points (of 10 possible points), with all but 2 scoring 5 points. A critical review of these studies indicated a disparity between oral and criterion standard temperature methods (eg, rectal and esophageal) specifically as the temperature increased. The difference was −0.50°C ± 0.31°C at rest and −0.58°C ± 0.75°C during a nonsteady state. Conclusions: Evidence suggests that, regardless of whether the assessment is recorded at rest or during periods of changing core temperature, oral temperature is an unsuitable diagnostic tool for determining body temperature because many measures demonstrated differences greater than the predetermined validity threshold of 0.27°C (0.5°F). In addition, the differences were greatest at the highest rectal temperatures. Oral temperature cannot accurately reflect core body temperature, probably because it is influenced by factors such as ambient air temperature, probe placement, and ingestion of fluids. Any reliance on oral temperature in an emergency, such as exertional heat stroke, might grossly underestimate temperature and delay proper diagnosis and treatment. PMID:22488144

Is oral temperature an accurate measurement of deep body temperature? A systematic review.

PubMed

Mazerolle, Stephanie M; Ganio, Matthew S; Casa, Douglas J; Vingren, Jakob; Klau, Jennifer

2011-01-01

Oral temperature might not be a valid method to assess core body temperature. However, many clinicians, including athletic trainers, use it rather than criterion standard methods, such as rectal thermometry. To critically evaluate original research addressing the validity of using oral temperature as a measurement of core body temperature during periods of rest and changing core temperature. In July 2010, we searched the electronic databases PubMed, Scopus, Cumulative Index to Nursing and Allied Health Literature (CINAHL), SPORTDiscus, Academic Search Premier, and the Cochrane Library for the following concepts: core body temperature, oral, and thermometers. Controlled vocabulary was used, when available, as well as key words and variations of those key words. The search was limited to articles focusing on temperature readings and studies involving human participants. Original research was reviewed using the Physiotherapy Evidence Database (PEDro). Sixteen studies met the inclusion criteria and subsequently were evaluated by 2 independent reviewers. All 16 were included in the review because they met the minimal PEDro score of 4 points (of 10 possible points), with all but 2 scoring 5 points. A critical review of these studies indicated a disparity between oral and criterion standard temperature methods (eg, rectal and esophageal) specifically as the temperature increased. The difference was -0.50°C ± 0.31°C at rest and -0.58°C ± 0.75°C during a nonsteady state. Evidence suggests that, regardless of whether the assessment is recorded at rest or during periods of changing core temperature, oral temperature is an unsuitable diagnostic tool for determining body temperature because many measures demonstrated differences greater than the predetermined validity threshold of 0.27°C (0.5°F). In addition, the differences were greatest at the highest rectal temperatures. Oral temperature cannot accurately reflect core body temperature, probably because it is influenced by factors such as ambient air temperature, probe placement, and ingestion of fluids. Any reliance on oral temperature in an emergency, such as exertional heat stroke, might grossly underestimate temperature and delay proper diagnosis and treatment.

Dynamics and complexity of body temperature in preterm infants nursed in incubators

PubMed Central

Jost, Kerstin; Pramana, Isabelle; Delgado-Eckert, Edgar; Kumar, Nitin; Datta, Alexandre N.; Frey, Urs; Schulzke, Sven M.

2017-01-01

Background Poor control of body temperature is associated with mortality and major morbidity in preterm infants. We aimed to quantify its dynamics and complexity to evaluate whether indices from fluctuation analyses of temperature time series obtained within the first five days of life are associated with gestational age (GA) and body size at birth, and presence and severity of typical comorbidities of preterm birth. Methods We recorded 3h-time series of body temperature using a skin electrode in incubator-nursed preterm infants. We calculated mean and coefficient of variation of body temperature, scaling exponent alpha (Talpha) derived from detrended fluctuation analysis, and sample entropy (TSampEn) of temperature fluctuations. Data were analysed by multilevel multivariable linear regression. Results Data of satisfactory technical quality were obtained from 285/357 measurements (80%) in 73/90 infants (81%) with a mean (range) GA of 30.1 (24.0–34.0) weeks. We found a positive association of Talpha with increasing levels of respiratory support after adjusting for GA and birth weight z-score (p<0.001; R2 = 0.38). Conclusion Dynamics and complexity of body temperature in incubator-nursed preterm infants show considerable associations with GA and respiratory morbidity. Talpha may be a useful marker of autonomic maturity and severity of disease in preterm infants. PMID:28448569

Extended lowered body temperature increases the effective CS-US interval in conditioned taste aversion for adult rats.

PubMed

Hinderliter, Charles F; Goodhart, Mark; Anderson, Matthew J; Misanin, James R

2002-06-01

Assuming body temperature correlates with metabolic activities, rate of body temperature recovery was manipulated to assess effects on long-trace conditioning in a conditioned taste-aversion paradigm. Following 10 min. access to a .1% saccharin solution and then 10 min. immersion in 0-0.5 degrees C water, two groups of 16 Wistar-derived, 81-113 day-old, male albino rats received either saline or lithium chloride injections 3 hr. later. These two groups were subdivided on basis of warming rate during the 3-hr. interval. Half of the rats recovered at room temperature (20 degrees to 21 degrees C), and half recovered in an incubator maintained at 30 degrees C. Maintaining a lowered body temperature between the conditioned stimulus and unconditioned stimulus allowed an association to be made at 3 hr., an interval that normally does not support conditioning. In contrast, lowering body temperature and then inducing a fast warming rate did not produce evidence of an aversion. It is suggested that maintaining a low body temperature over the interval between the presentation of the conditioned stimulus and unconditioned stimulus slows a metabolic clock that extends the measured interval at which associations can be made using conditioned taste-aversion procedures.

Dynamics and complexity of body temperature in preterm infants nursed in incubators.

PubMed

Jost, Kerstin; Pramana, Isabelle; Delgado-Eckert, Edgar; Kumar, Nitin; Datta, Alexandre N; Frey, Urs; Schulzke, Sven M

2017-01-01

Poor control of body temperature is associated with mortality and major morbidity in preterm infants. We aimed to quantify its dynamics and complexity to evaluate whether indices from fluctuation analyses of temperature time series obtained within the first five days of life are associated with gestational age (GA) and body size at birth, and presence and severity of typical comorbidities of preterm birth. We recorded 3h-time series of body temperature using a skin electrode in incubator-nursed preterm infants. We calculated mean and coefficient of variation of body temperature, scaling exponent alpha (Talpha) derived from detrended fluctuation analysis, and sample entropy (TSampEn) of temperature fluctuations. Data were analysed by multilevel multivariable linear regression. Data of satisfactory technical quality were obtained from 285/357 measurements (80%) in 73/90 infants (81%) with a mean (range) GA of 30.1 (24.0-34.0) weeks. We found a positive association of Talpha with increasing levels of respiratory support after adjusting for GA and birth weight z-score (p<0.001; R2 = 0.38). Dynamics and complexity of body temperature in incubator-nursed preterm infants show considerable associations with GA and respiratory morbidity. Talpha may be a useful marker of autonomic maturity and severity of disease in preterm infants.

Definitions of Health Terms: General Health

MedlinePlus

... needs to stay healthy. You can start by learning these general health terms. Find more definitions on Fitness | General Health | Minerals | Nutrition | Vitamins Basal Body Temperature Basal body temperature is your temperature at rest ...

Speed over efficiency: locusts select body temperatures that favour growth rate over efficient nutrient utilization

PubMed Central

Miller, Gabriel A.; Clissold, Fiona J.; Mayntz, David; Simpson, Stephen J.

2009-01-01

Ectotherms have evolved preferences for particular body temperatures, but the nutritional and life-history consequences of such temperature preferences are not well understood. We measured thermal preferences in Locusta migratoria (migratory locusts) and used a multi-factorial experimental design to investigate relationships between growth/development and macronutrient utilization (conversion of ingesta to body mass) as a function of temperature. A range of macronutrient intake values for insects at 26, 32 and 38°C was achieved by offering individuals high-protein diets, high-carbohydrate diets or a choice between both. Locusts placed in a thermal gradient selected temperatures near 38°C, maximizing rates of weight gain; however, this enhanced growth rate came at the cost of poor protein and carbohydrate utilization. Protein and carbohydrate were equally digested across temperature treatments, but once digested both macronutrients were converted to growth most efficiently at the intermediate temperature (32°C). Body temperature preference thus yielded maximal growth rates at the expense of efficient nutrient utilization. PMID:19625322

Body temperature measurement in mice during acute illness: implantable temperature transponder versus surface infrared thermometry.

PubMed

Mei, Jie; Riedel, Nico; Grittner, Ulrike; Endres, Matthias; Banneke, Stefanie; Emmrich, Julius Valentin

2018-02-23

Body temperature is a valuable parameter in determining the wellbeing of laboratory animals. However, using body temperature to refine humane endpoints during acute illness generally lacks comprehensiveness and exposes to inter-observer bias. Here we compared two methods to assess body temperature in mice, namely implanted radio frequency identification (RFID) temperature transponders (method 1) to non-contact infrared thermometry (method 2) in 435 mice for up to 7 days during normothermia and lipopolysaccharide (LPS) endotoxin-induced hypothermia. There was excellent agreement between core and surface temperature as determined by method 1 and 2, respectively, whereas the intra- and inter-subject variation was higher for method 2. Nevertheless, using machine learning algorithms to determine temperature-based endpoints both methods had excellent accuracy in predicting death as an outcome event. Therefore, less expensive and cumbersome non-contact infrared thermometry can serve as a reliable alternative for implantable transponder-based systems for hypothermic responses, although requiring standardization between experimenters.

Cooler biologically compatible core body temperatures may prolong longevity and combat neurodegenerative disorders.

PubMed

Salerian, Alen J; Saleri, Nansen G

2006-01-01

Scientific evidence suggests the critical role of temperature in regulating three mechanisms contributing to cellular damage: Oxidative stress, oxygen demand overload and inflammation. In this article, we propose that the Arrhenius rate law has a profound impact on aging and a variety of neurodegenerative disorders including Alzheimer's disease, and we review the supporting evidence. Published studies suggest empirical correlations between temperature and lifespan of various organisms, bolstering the hypothesis that variations in lifespan may stem from differences in the mitochondrial production rates of radicals - a process also influenced by temperature. Given the exponential temperature dependency of all biochemical factors, cooler body temperatures may promote longevity and combat neurodegenerative disorders. This promises to offer extraordinary yet unexplored weapons against two formidable enemies of the human body: aging and neurodegenerative disorders. Stated in the form of a thesis referred to as Salerian and Saleri Temperature Thesis (SSTT): "Cooler biologically compatible core body temperatures prolong lifespan and are of value to combat illness". Double blind studies of SSTT in therapeutic strategies against amyotrophic lateral sclerosis (ALS) or early-stage Alzheimer's disease may offer a reasonable first stage to validate SSTT. In view of the known rapid progressive neurodegeneration associated with ALS, minute variations in core body temperature may, in fact, demonstrate statistically significant differences in disease progression.

Physiology response of the indigenous cattle breeds to the environment in West Sumbawa, Indonesia

NASA Astrophysics Data System (ADS)

Aritonang, S. B.; Yuniati, R.; Abinawanto, Imron, M.; Bowolaksono, A.

2017-07-01

Heat stress in cattle welfare is a growing concern because of increase in ambient temperature due to global warming. Physiological adaptation is as a way to survive and reproduce by regulation internal body temperature. West Sumbawa is a dry tropic area in eastern Indonesia where its temperature range is 24-38 °C and relative humidity is 50-90 %. This study aimed to determine the physiological response of indigenous cattle i.e. Bali cattle and Sumbawa Ongole cattle to the environment in West Sumbawa. Skin and rectal temperature and respiration rate within one minute were measured as physiology profiles from seven Bali cattle and two Sumbawa Ongole cattle. They were measured every 7.00 am and 15.00 pm for five consecutive days in August 2016. The results of measurements physiology profiles differ significantly between morning and afternoon among cattle breeds. Body temperature and respiration rate were significantly different among breeds (p < 0.05). Body temperature was lower but respiration rate of Sumbawa Ongole was higher than Bali cattle. Increased respiration rate of breeds was positively correlated with Temperature and Humidity Index (THI) value (p < 0.05), but neither was body temperature. Physiological response of Bali cattle to environmental West Sumbawa through the increase in body temperature, whereas Sumbawa Ongole cattle through increasing in respiration rate.

Development of SiAlON materials

NASA Technical Reports Server (NTRS)

Layden, G. K.

1977-01-01

Cold pressing and sintering techniques were used to produce ceramic bodies in which the major phase was beta prime Si3-Al-O-N4 solid solution. A variety of foreign oxides were used to promote liquid phase sintering, and this resulted in the incorporation of additional solid phases in the ceramic bodies which controlled elevated temperature properties. None of the bodies studied to date exhibited both adequate high temperature mechanical properties and oxidation resistance. Criteria are suggested to guide the formulation of bodies with improved high temperature properties.

Saturday night fever in ecstasy/MDMA dance clubbers: Heightened body temperature and associated psychobiological changes

PubMed Central

Parrott, Andrew C; Young, Lucy

2014-01-01

Aims and rationale: to investigate body temperature and thermal self-ratings of Ecstasy/MDMA users at a Saturday night dance club. Methods: 68 dance clubbers (mean age 21.6 years, 30 females and 38 males), were assessed at a Saturday night dance club, then 2–3 d later. Three subgroups were compared: 32 current Ecstasy users who had taken Ecstasy/MDMA that evening, 10 abstinent Ecstasy/MDMA users on other psychoactive drugs, and 26 non-user controls (predominantly alcohol drinkers). In a comparatively quiet area of the dance club, each unpaid volunteer had their ear temperature recorded, and completed a questionnaire on thermal feelings and mood states. A similar questionnaire was repeated 2–3 d later by mobile telephone. Results: Ecstasy/MDMA users had a mean body temperature 1.2°C higher than non-user controls (P < 0.001), and felt significantly hotter and thirstier. The abstinent Ecstasy/MDMA polydrug user group had a mean body temperature intermediate between the other 2 groups, significantly higher than controls, and significantly lower than current Ecstasy/MDMA users. After 2–3 d of recovery, the Ecstasy/MDMA users remained significantly ‘thirstier’. Higher body temperature while clubbing was associated with greater Ecstasy/MDMA usage at the club, and younger age of first use. Higher temperature also correlated with lower elation and poor memory 2–3 d later. It also correlated positively with nicotine, and negatively with cannabis. Conclusions: Ecstasy/MDMA using dance clubbers had significantly higher body temperature than non-user controls. This heightened body temperature was associated with a number of adverse psychobiological consequences, including poor memory. PMID:27626048

Body temperature responses to handling stress in wintering Black-capped Chickadees (Poecile atricapillus L.).

PubMed

Lewden, Agnès; Nord, Andreas; Petit, Magali; Vézina, François

2017-10-01

Body temperature variation in response to acute stress is typically characterized by peripheral vasoconstriction and a concomitant increase in core body temperature (stress-induced hyperthermia). It is poorly understood how this response differs between species and within individuals of the same species, and how it is affected by the environment. We therefore investigated stress-induced body temperature changes in a non-model species, the Black-capped Chickadee, in two environmental conditions: outdoors in low ambient temperature (mean: -6.6°C), and indoors, in milder ambient temperature close to thermoneutrality (mean: 18.7°C). Our results show that the change in body temperature in response to the same handling stressor differs in these conditions. In cold environments, we noted a significant decrease in core body temperature (-2.9°C), whereas the response in mild indoor conditions was weak and non-significant (-0.6°C). Heat loss in outdoor birds was exacerbated when birds were handled for longer time. This may highlight the role of behavioral thermoregulation and heat substitution from activity to body temperature maintenance in harsh condition. Importantly, our work also indicates that changes in the physical properties of the bird during handling (conductive cooling from cold hands, decreased insulation from compression of plumage and prevention of ptiloerection) may have large consequences for thermoregulation. This might explain why females, the smaller sex, lost more heat than males in the experiment. Because physiological and physical changes during handling may carry over to affect predation risk and maintenance of energy balance during short winter days, we advice caution when designing experimental protocols entailing prolonged handling of small birds in cold conditions. Copyright © 2017 Elsevier Inc. All rights reserved.

Body and brain temperature coupling: the critical role of cerebral blood flow

PubMed Central

Ackerman, Joseph J. H.; Yablonskiy, Dmitriy A.

2010-01-01

Direct measurements of deep-brain and body-core temperature were performed on rats to determine the influence of cerebral blood flow (CBF) on brain temperature regulation under static and dynamic conditions. Static changes of CBF were achieved using different anesthetics (chloral hydrate, CH; α-chloralose, αCS; and isoflurane, IF) with αCS causing larger decreases in CBF than CH and IF; dynamic changes were achieved by inducing transient hypercapnia (5% CO2 in 40% O2 and 55% N2). Initial deep-brain/body-core temperature differentials were anesthetic-type dependent with the largest differential observed with rats under αCS anesthesia (ca. 2°C). Hypercapnia induction raised rat brain temperature under all three anesthesia regimes, but by different anesthetic-dependent amounts correlated with the initial differentials—αCS anesthesia resulted in the largest brain temperature increase (0.32 ± 0.08°C), while CH and IF anesthesia lead to smaller increases (0.12 ± 0.03 and 0.16 ± 0.05°C, respectively). The characteristic temperature transition time for the hypercapnia-induced temperature increase was 2–3 min under CH and IF anesthesia and ~4 min under αCS anesthesia. We conclude that both, the deep-brain/body-core temperature differential and the characteristic temperature transition time correlate with CBF: a lower CBF promotes higher deep-brain/body-core temperature differentials and, upon hypercapnia challenge, longer characteristic transition times to increased temperatures. PMID:19277681

Body and brain temperature coupling: the critical role of cerebral blood flow.

PubMed

Zhu, Mingming; Ackerman, Joseph J H; Yablonskiy, Dmitriy A

2009-08-01

Direct measurements of deep-brain and body-core temperature were performed on rats to determine the influence of cerebral blood flow (CBF) on brain temperature regulation under static and dynamic conditions. Static changes of CBF were achieved using different anesthetics (chloral hydrate, CH; alpha-chloralose, alphaCS; and isoflurane, IF) with alphaCS causing larger decreases in CBF than CH and IF; dynamic changes were achieved by inducing transient hypercapnia (5% CO(2) in 40% O(2) and 55% N(2)). Initial deep-brain/body-core temperature differentials were anesthetic-type dependent with the largest differential observed with rats under alphaCS anesthesia (ca. 2 degrees C). Hypercapnia induction raised rat brain temperature under all three anesthesia regimes, but by different anesthetic-dependent amounts correlated with the initial differentials--alphaCS anesthesia resulted in the largest brain temperature increase (0.32 +/- 0.08 degrees C), while CH and IF anesthesia lead to smaller increases (0.12 +/- 0.03 and 0.16 +/- 0.05 degrees C, respectively). The characteristic temperature transition time for the hypercapnia-induced temperature increase was 2-3 min under CH and IF anesthesia and approximately 4 min under alphaCS anesthesia. We conclude that both, the deep-brain/body-core temperature differential and the characteristic temperature transition time correlate with CBF: a lower CBF promotes higher deep-brain/body-core temperature differentials and, upon hypercapnia challenge, longer characteristic transition times to increased temperatures.

Ischemia/reperfusion injury resistance in hibernators is more than an effect of reduced body temperature or winter season.

PubMed

Bogren, Lori K; Drew, Kelly L

2014-01-01

Hibernating mammals are resistant to injury following cardiac arrest. The basis of this protection has been proposed to be due to their ability to lower body temperature or metabolic rate in a seasonally-dependent manner. However, recent studies have shown that neither reduced body temperature nor hibernation season are components this protection.

Thermophysiology of Tyrannosaurus rex: Evidence from Oxygen Isotopes.

PubMed

Barrick, R E; Showers, W J

1994-07-08

The oxygen isotopic composition of vertebrate bone phosphate (delta(p)) is related to ingested water and to the body temperature at which the bone forms. The delta(p) is in equilibrium with the individual's body water, which is at a physiological steady state throughout the body. Therefore, intrabone temperature variation and the mean interbone temperature differences of well-preserved fossil vertebrates can be determined from the deltap variation. Values of delta(p) from a well-preserved Tyrannosaurus rex suggest that this species maintained homeothermy with less than 4 degrees C of variability in body temperature. Maintenance of homeothermy implies a relatively high metabolic rate that is similar to that of endotherms.

Agmatine attenuates stress- and lipopolysaccharide-induced fever in rats

PubMed Central

Aricioglu, Feyza; Regunathan, Soundar

2010-01-01

Physiological stress evokes a number of responses, including a rise in body temperature, which has been suggested to be the result of an elevation in the thermoregulatory set point. This response seems to share similar mechanisms with infectious fever. The aim of the present study was to investigate the effect of agmatine on different models of stressors [(restraint and lipopolysaccaride (LPS)] on body temperature. Rats were either restrained for 4 h or injected with LPS, both of these stressors caused an increase in body temperature. While agmatine itself had no effect on body temperature, treatment with agmatine (20, 40, 80 mg/kg intraperitoneally) dose dependently inhibited stress- and LPS-induced hyperthermia. When agmatine (80 mg/kg) was administered 30 min later than LPS (500 μg/kg) it also inhibited LPS-induced hyperthermia although the effect became significant only at later time points and lower maximal response compared to simultaneous administration. To determine if the decrease in body temperature is associated with an anti-inflammatory effect of agmatine, the nitrite/nitrate levels in plasma was measured. Agmatine treatment inhibited LPS-induced production of nitrates dose dependently. As an endogenous molecule, agmatine has the capacity to inhibit stress- and LPS-induced increases in body temperature. PMID:15936786

[Clinical significance of peak body temperature, white blood cell count, and C-reactive protein level in febrile episodes among geriatric inpatients].

PubMed

Ikematsu, H; Nabeshima, A; Yamaga, S; Yamaji, K; Kakuda, K; Ueno, K; Hayashi, J; Shirai, T; Hara, H; Kashiwagi, S

1997-06-01

To investigate the clinical implication of peak body temperature, peripheral blood white blood cell (WBC) count, and serum C-reactive protein (CRP) level in febrile symptoms among geriatric hospitalized patients, they were analyzed in 968 febrile episodes obtained from 433 hospitalized patients in the referred hospital. Episodes of one day duration were most frequent (41.6%). WBC count was elevated over 8000/microliters in 475 episodes (49.1%) and CRP exceeded 1.0 mg/dl in 770 episodes (79.5%). Frequency of WBC elevation decreased and frequency of CRP elevation increased according to the time course. The mean value of CRP increased significantly according to the time course. The frequency of WBC count increase and CRP elevation and their averages correlated to the peak body temperature. The peak body temperature displayed the most striking correlation to the length of febrile episodes among three clinical indicators, peak body temperature, WBC count, and CRP level. These results indicate that the elevation of WBC count and/or CRP level is frequent in geriatric patients with febrile symptoms. Peak body temperature may serve as a clinical indicator of the severy of the febrile disease occurring in geriatric patients.

Ghrelin-induced hypothermia: A Physiological basis but no clinical risk

PubMed Central

Wiedmer, Petra; Strasser, Florian; Horvath, Tamas L.; Blum, David; DiMarchi, Richard; Lutz, Thomas; Schürmann, Annette; Joost, Hans-Georg; Tschöp, Matthias H.; Tong, Jenny

2011-01-01

Ghrelin increases food intake and decreases energy expenditure, promoting a positive energy balance. We observed a single case of serious hypothermia during sustained ghrelin treatment in a male subject, suggesting that ghrelin may play a role in the regulation of body temperature. We therefore investigated the effect of ghrelin treatment on body temperature in rodents and humans under controlled conditions. Intriguingly, we could demonstrate ghrelin binding in axon terminals of the medial preoptic area of the hypothalamus located in the vicinity of cold-sensitive neurons. This localization of ghrelin receptors provides a potential anatomical basis for the regulation of body temperature by ghrelin. However, our follow-up studies also indicated that neither a chronic i.c.v. application of ghrelin in rats, nor a single s.c. injection under cold exposure in mice resulted in a relevant decrease in body core temperature. In addition, a four-hour intravenous ghrelin infusion did not decrease body surface temperature in healthy humans. We concluded that while there is a theoretical molecular basis for ghrelin to modify body temperature in mammals, its magnitude is irrelevant under physiologic circumstances. Hypothermia is not likely to represent a serious risk associated with this agent and pathway. PMID:21513721

EFFECT OF ACTIVE COOLING AND α-2 ADRENOCEPTOR ANTAGONISM ON CORE TEMPERATURE IN ANESTHETIZED BROWN BEARS (URSUS ARCTOS).

PubMed

Ozeki, Larissa Mourad; Caulkett, Nigel; Stenhouse, Gordon; Arnemo, Jon M; Fahlman, Åsa

2015-06-01

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°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°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°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.

Body temperature and mortality in patients with acute respiratory distress syndrome.

PubMed

Schell-Chaple, Hildy M; Puntillo, Kathleen A; Matthay, Michael A; Liu, Kathleen D

2015-01-01

Little is known about the relationship between body temperature and outcomes in patients with acute respiratory distress syndrome (ARDS). A better understanding of this relationship may provide evidence for fever suppression or warming interventions, which are commonly applied in practice. To examine the relationship between body temperature and mortality in patients with ARDS. Secondary analysis of body temperature and mortality using data from the ARDS Network Fluid and Catheter Treatment Trial (n = 969). Body temperature at baseline and on study day 2, primary cause of ARDS, severity of illness, and 90-day mortality were analyzed by using multiple logistic regression. Mean baseline temperature was 37.5°C (SD, 1.1°C; range, 27.2°C-40.7°C). At baseline, fever (≥ 38.3°C) was present in 23% and hypothermia (< 36°C) in 5% of the patients. Body temperature was a significant predictor of 90-day mortality after primary cause of ARDS and score on the Acute Physiology and Chronic Health Evaluation III were adjusted for. Higher temperature was associated with decreased mortality: for every 1°C increase in baseline temperature, the odds of death decreased by 15% (odds ratio, 0.85; 95% CI, 0.73-0.98, P = .03). When patients were divided into 5 temperature groups, mortality was lower with higher temperature (P for trend = .02). Early in ARDS, fever is associated with improved survival rates. Fever in the acute phase response to lung injury and its relationship to recovery may be an important factor in determining patients' outcome and warrants further study. ©2015 American Association of Critical-Care Nurses.

Body Temperature and Mortality in Patients with Acute Respiratory Distress Syndrome

PubMed Central

Schell-Chaple, Hildy M.; Puntillo, Kathleen A.; Matthay, Michael A.; Liu, Kathleen D.

2015-01-01

Background Little is known about the relationship between body temperature and outcomes in patients with acute respiratory distress syndrome (ARDS). A better understanding of this relationship may provide evidence for fever suppression or warming interventions, which are commonly applied in practice. Objective To examine the relationship between body temperature and mortality in patients with ARDS. Methods Secondary analysis of body temperature and mortality using data from the ARDS Network Fluid and Catheter Treatment Trial (n =969). Body temperature at baseline and on study day 2, primary cause of ARDS, severity of illness, and 90-day mortality were analyzed by using multiple logistic regression. Results Mean baseline temperature was 37.5°C (SD, 1.1°C; range, 27.2°C-40.7°C). At baseline, fever (≥ 38.3°C) was present in 23% and hypothermia (< 36°C) in 5% of the patients. Body temperature was a significant predictor of 90-day mortality after primary cause of ARDS and score on the Acute Physiology and Chronic Health Evaluation III were adjusted for. Higher temperature was associated with decreased mortality: for every 1°C increase in baseline temperature, the odds of death decreased by 15% (odds ratio, 0.85; 95% CI, 0.73-0.98, P = .03). When patients were divided into 5 temperature groups, mortality was lower with higher temperature (P for trend=.02). Conclusions Early in ARDS, fever is associated with improved survival rates. Fever in the acute phase response to lung injury and its relationship to recovery may be an important factor in determining patients' outcome and warrants further study. PMID:25554550

Considerations for the measurement of core, skin and mean body temperatures.

PubMed

Taylor, Nigel A S; Tipton, Michael J; Kenny, Glen P

2014-12-01

Despite previous reviews and commentaries, significant misconceptions remain concerning deep-body (core) and skin temperature measurement in humans. Therefore, the authors have assembled the pertinent Laws of Thermodynamics and other first principles that govern physical and physiological heat exchanges. The resulting review is aimed at providing theoretical and empirical justifications for collecting and interpreting these data. The primary emphasis is upon deep-body temperatures, with discussions of intramuscular, subcutaneous, transcutaneous and skin temperatures included. These are all turnover indices resulting from variations in local metabolism, tissue conduction and blood flow. Consequently, inter-site differences and similarities may have no mechanistic relationship unless those sites have similar metabolic rates, are in close proximity and are perfused by the same blood vessels. Therefore, it is proposed that a gold standard deep-body temperature does not exist. Instead, the validity of each measurement must be evaluated relative to one's research objectives, whilst satisfying equilibration and positioning requirements. When using thermometric computations of heat storage, the establishment of steady-state conditions is essential, but for clinically relevant states, targeted temperature monitoring becomes paramount. However, when investigating temperature regulation, the response characteristics of each temperature measurement must match the forcing function applied during experimentation. Thus, during dynamic phases, deep-body temperatures must be measured from sites that track temperature changes in the central blood volume. Copyright © 2014 Elsevier Ltd. All rights reserved.

A Novel Intra-body Sensor for Vaginal Temperature Monitoring

PubMed Central

Rodrigues, Joel J. P. C.; Caldeira, João; Vaidya, Binod

2009-01-01

Over the years some medical studies have tried to better understand the internal behavior of human beings. Many researchers in this domain have been striving to find relationships between intra-vaginal temperature and certain female health conditions, such as ovulation and fertile period since woman’s intra-vaginal temperature is one of the body parameters most preferred in such studies. However, due to lack of a appropriate technology, medical research devoted to studying correlations of such body parameters with certain womans’ body phenomena could not obtain better results. This article presents the design and implementation of a novel intra-body sensor for acquisition and monitoring of intra-vaginal temperatures. This novel intra-body sensor provides data collection that is used for studying the relation between temperature variations and female health conditions, such as anticipation and monitoring of the ovulation period, detection of pregnancy contractions, preterm labor prevention, etc.. The motivation for this work focuses on the development of this new intra-body sensor that will represent a major step in medical technology. The novel sensor was tested and validated on hospitalized women as well as normal healthy women. Finally our medical team has attested to the accuracy, usability and performance of this novel intra-body sensor. PMID:22574046

Prediction of brain tissue temperature using near-infrared spectroscopy

PubMed Central

Holper, Lisa; Mitra, Subhabrata; Bale, Gemma; Robertson, Nicola; Tachtsidis, Ilias

2017-01-01

Abstract. Broadband near-infrared spectroscopy (NIRS) can provide an endogenous indicator of tissue temperature based on the temperature dependence of the water absorption spectrum. We describe a first evaluation of the calibration and prediction of brain tissue temperature obtained during hypothermia in newborn piglets (animal dataset) and rewarming in newborn infants (human dataset) based on measured body (rectal) temperature. The calibration using partial least squares regression proved to be a reliable method to predict brain tissue temperature with respect to core body temperature in the wavelength interval of 720 to 880 nm with a strong mean predictive power of R2=0.713±0.157 (animal dataset) and R2=0.798±0.087 (human dataset). In addition, we applied regression receiver operating characteristic curves for the first time to evaluate the temperature prediction, which provided an overall mean error bias between NIRS predicted brain temperature and body temperature of 0.436±0.283°C (animal dataset) and 0.162±0.149°C (human dataset). We discuss main methodological aspects, particularly the well-known aspect of over- versus underestimation between brain and body temperature, which is relevant for potential clinical applications. PMID:28630878

Thermal Imaging of Body Surface Temperature Distribution in Women with Anorexia Nervosa.

PubMed

Chudecka, Monika; Lubkowska, Anna

2016-01-01

The drastic reduction in body weight observed in anorexia nervosa (AN) leads to various endocrine changes and consequently to disturbance in thermoregulation mechanisms and body temperature. Thermography allows for a noninvasive diagnosis of the distribution of skin surface temperatures, which is especially important for difficult patients such as women with AN, who are often very sensitive and difficult to treat. The main aim of this study was to measure the mean temperatures (Tmean ) of selected body areas in young women diagnosed with AN and identify those areas where the temperature differences were particularly significant between healthy women and them. Additionally, we determined the relationships between body mass index, body composition (especially subcutaneous and VFM) and the value of mean surface temperature (Tmean ) in AN woman. In the subjects with AN, Tmean of the abdomen, lower back and thighs were significantly higher than in the reference group, while Tmean of the hands were significantly lower. Among other things, analysis showed a significant negative correlation between Tmean of the abdomen, lower back and thighs, and the mass of subcutaneous and visceral fat. The lower Tmean of the hand was directly proportional to the reduced anthropomorphic parameters. The direct evaluation of body surface temperature distribution could provide clinical implications for the treatment of anorexic patients, including the potential use of thermotherapy in stimulating the circulatory system, especially in hypothermia, bradycardia and hypotension. Copyright © 2015 John Wiley & Sons, Ltd and Eating Disorders Association.

Effects of season, temperature, and body mass on the standard metabolic rate of tegu lizards (Tupinambis merianae).

PubMed

Toledo, Luís F; Brito, Simone P; Milsom, William K; Abe, Augusto S; Andrade, Denis V

2008-01-01

Abstract This study examined how the standard metabolic rate of tegu lizards, a species that undergoes large ontogenetic changes in body weight with associated changes in life-history traits, is affected by changes in body mass, body temperature, season, and life-history traits. We measured rates of oxygen consumption (Vo(2)) in 90 individuals ranging in body mass from 10.4 g to 3.75 kg at three experimental temperatures (17 degrees , 25 degrees , and 30 degrees C) over the four seasons. We found that standard metabolic rate scaled to the power of 0.84 of body mass at all experimental temperatures in all seasons and that thermal sensitivity of metabolism was relatively low (Q(10) approximately 2.0-2.5) over the range from 17 degrees to 30 degrees C regardless of body size or season. Metabolic rates did vary seasonally, being higher in spring and summer than in autumn and winter at the same temperatures, and this was true regardless of animal size. Finally, in this study, the changes in life-history traits that occurred ontogenetically were not accompanied by significant changes in metabolic rate.

The effect of temperature and body weight on the routine metabolic rate and postprandial metabolic response in mulloway, Argyrosomus japonicus.

PubMed

Pirozzi, Igor; Booth, Mark A

2009-09-01

Specific dynamic action (SDA) is the energy expended on the physiological processes associated with meal digestion and is strongly influenced by the characteristics of the meal and the body weight (BW) and temperature of the organism. This study assessed the effects of temperature and body weight on the routine metabolic rate (RMR) and postprandial metabolic response in mulloway, Argyrosomus japonicus. RMR and SDA were established at 3 temperatures (14, 20 and 26 degrees C). 5 size classes of mulloway ranging from 60 g to 1.14 kg were used to establish RMR with 3 of the 5 size classes (60, 120 and 240 g) used to establish SDA. The effect of body size on the mass-specific RMR (mg O(2) kg(-1) h(-1)) varied significantly depending on the temperature; there was a greater relative increase in the mass-specific RMR for smaller mulloway with increasing temperature. No statistical differences were found between the mass exponent (b) values at each temperature when tested against H(0): b=0.8. The gross RMR of mulloway (mg O(2) fish(-1) h(-1)) can be described as function of temperature (T; 14-26 degrees C) as: (0.0195T-0.0454)BW(g)(0.8) and the mass-specific RMR (mg O(2) kg(-1) h(-1)) can be described as: (21.042T-74.867)BW(g)(-0.2). Both SDA duration and time to peak SDA were influenced by temperature and body weight; SDA duration occurred within 41-89 h and peak time occurred within 17-38 h of feeding. The effect of body size on peak metabolic rate varied significantly depending on temperature, generally increasing with temperature and decreasing with increasing body size. Peak gross oxygen consumption (MO(2): mg O(2) fish(-1) h(-1)) scaled allometrically with BW. Temperature, but not body size, significantly affected SDA scope, although the difference was numerically small. There was a trend for MO(2) above RMR over the SDA period to increase with temperature; however, this was not statistically significant. The average proportion of energy expended over the SDA period (SDA coefficient) ranged from approximately 7-13% of the total DE intake while the proportion of total energy expended on SDA above RMR ranged from approximately 16-27%.

Non-invasive body temperature measurement of wild chimpanzees using fecal temperature decline.

PubMed

Jensen, Siv Aina; Mundry, Roger; Nunn, Charles L; Boesch, Christophe; Leendertz, Fabian H

2009-04-01

New methods are required to increase our understanding of pathologic processes in wild mammals. We developed a noninvasive field method to estimate the body temperature of wild living chimpanzees habituated to humans, based on statistically fitting temperature decline of feces after defecation. The method was established with the use of control measures of human rectal temperature and subsequent changes in fecal temperature over time. The method was then applied to temperature data collected from wild chimpanzee feces. In humans, we found good correspondence between the temperature estimated by the method and the actual rectal temperature that was measured (maximum deviation 0.22 C). The method was successfully applied and the average estimated temperature of the chimpanzees was 37.2 C. This simple-to-use field method reliably estimates the body temperature of wild chimpanzees and probably also other large mammals.

The impact of hypothermia on emergence from isoflurane anesthesia in orexin neuron-ablated mice.

PubMed

Kuroki, Chiharu; Takahashi, Yoshiko; Ootsuka, Youichirou; Kanmura, Yuichi; Kuwaki, Tomoyuki

2013-05-01

Orexin neurons regulate the sleep/wake cycle and are proposed to influence general anesthesia. In animal experiments, orexin neurons have been shown to drive emergence from general anesthesia. In human studies, however, the role of orexin neurons remains controversial, owing at least, in part, to the fact that orexin neurons are multifunctional. Orexin neurons regulate not only the sleep/wake cycle, but also body temperature. We hypothesized that orexin neurons do not directly regulate emergence from anesthesia, but instead affect emergence indirectly through thermoregulation because anesthesia-induced hypothermia can greatly influence emergence time. To test our hypothesis, we used simultaneous measurement of body temperature and locomotor activity. We used male orexin neuron-ablated (ORX-AB) mice and their corresponding wild-type (WT) littermates to investigate the role of orexin neurons in emergence. Body temperature was recorded using an intraperitoneally implanted telemetric probe, and locomotor activity was measured using an infrared motion sensor. Induction of anesthesia and emergence from anesthesia were defined behaviorally as loss and return, respectively, of body movement. Mice received general anesthesia with 1.5% isoflurane in 100% oxygen for 30 minutes under 3 conditions. In the first experiment, the anesthesia chamber was warmed (32 °C), ensuring a constant body temperature of animals during anesthesia. In the second experiment, the anesthesia chamber was maintained at room temperature (25 °C), allowing body temperature to fluctuate. In the third experiment in WT mice, the anesthesia chamber was cooled (23 °C) so that their body temperature would decrease to the comparable value to that obtained in the ORX-AB mice during room temperature condition. In the warmed condition, there were no significant differences between the ORX-AB and control mice with respect to body temperature, locomotor activity, induction time, or emergence time. In the room temperature condition, however, anesthesia-induced hypothermia was greater and longer lasting in ORX-AB mice than that in WT mice. Emergence time in ORX-AB mice was significantly prolonged from the warmed condition (14.2 ± 0.8 vs 6.0 ± 1.1 minutes) whereas that in WT mice was not different (7.4 ± 0.8 vs 4.9 ± 0.2 minutes). When body temperature was decreased by cooling in WT mice, emergence time was prolonged to 12.4 ± 1.3 minutes. Induction time did not differ among temperature conditions or genotypes. The effect of orexin deficiency to impair thermoregulation during general anesthesia is of sufficient magnitude that body temperature must be appropriately controlled when studying the role of orexin neurons in emergence from anesthesia.

Thermoregulation of fish and turtles in thermally stressed habitats. Annual progress report, October 1, 1977--September 30, 1978

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spotila, J.R.

1978-06-01

Morphometric and heating and cooling studies on over 100 largemouth bass, Micropterus salmoides, have provided the data needed to refine the time-dependent body temperature model for fish. The model can now track the changes in body temperature of a bass if its weight and water temperature are known. The model is most sensitive to body diameter, body wall thickness, and tissue conductivity. Doubling tissue conductivity is equivalent to decreasing body diameter by a factor or two. Turtles, Chrysemys scripta, living in the heated portion of a cooling reservoir facultatively exploit the warmed water (..delta..T = 4 to 10/sup 0/C) asmore » an auxiliary heat source for behavioral thermoregulation. Turtles in the heated arm of PAR pond have a smaller home range (200 m) than turtles in an ambient portion of the reservoir (507 m). The ability of animals to thermoregulate at a high constant body temperature depends upon the constraints imposed on them by their body size and physical characteristics and those of their environment. The net heat production required to maintain a specific body temperature changes as the size of an ectotherm increases. Operative environmental temperature is an appropriate measure of environmental heat loading and can be used as a predictor of turtle behavior. This concept may become very valuable in quantifying the effect of thermal effluents on turtle and fish behavior.« less

Temperature regulation and metabolism of an Australian bat, Chalinolobus gouldii (Chiroptera:Vespertilionidae) when euthermic and torpid.

PubMed

Hosken, D J; Withers, P C

1997-01-01

The thermal and metabolic physiology of Chalinolobus gouldii, an Australian vespertilionid bat, was studied in the laboratory using flow-through respirometry. Chalinolobus gouldii exhibits a clear pattern of euthermic thermoregulation, typical of endotherms with respect to body temperature and rate of oxygen consumption. The basal metabolic rate of euthermic Chalinolobus gouldii is approximately 86% of that predicted for a 17.5-g mammal and falls into the range of mass-specific basal metabolic rates ascribed to vespertilionid bats. However, like most vespertilionid bats, Chalinolobus gouldii displays extreme thermolability. It is able to enter into torpor and spontaneously arouse at ambient temperatures as low as 5 degrees C. Torpid bats thermoconform at moderate ambient temperature, with body temperature approximately ambient temperature, and have a low rate of oxygen consumption determined primarily by Q10 effects. At low ambient temperature (< 10 degrees C), torpid C. gouldii begin to regulate their body temperature by increased metabolic heat production; they tend to maintain a higher body temperature at low ambient temperature than do many northern hemisphere hibernating bats. Use of torpor leads to significant energy savings. The evaporative water loss of euthermic bats is relatively high, which seems unusual for a bat whose range includes extremely arid areas of Australia, and is reduced during torpor. The thermal conductance of euthermic C. gouldii is less than that predicted for a mammal of its size. The thermal conductance is considerably lower for torpid bats at intermediate body temperature and ambient temperature, but increases to euthermic values for torpid bats when thermoregulating at low ambient temperature.

Comparison of forced-air warming systems with lower body blankets using a copper manikin of the human body.

PubMed

Bräuer, A; English, M J M; Lorenz, N; Steinmetz, N; Perl, T; Braun, U; Weyland, W

2003-01-01

Forced-air warming has gained high acceptance as a measure for the prevention of intraoperative hypothermia. However, data on heat transfer with lower body blankets are not yet available. This study was conducted to determine the heat transfer efficacy of six complete lower body warming systems. Heat transfer of forced-air warmers can be described as follows:[1]Qdot;=h.DeltaT.A where Qdot; = heat transfer [W], h = heat exchange coefficient [W m-2 degrees C-1], DeltaT = temperature gradient between blanket and surface [ degrees C], A = covered area [m2]. We tested the following forced-air warmers in a previously validated copper manikin of the human body: (1) Bair Hugger and lower body blanket (Augustine Medical Inc., Eden Prairie, MN); (2) Thermacare and lower body blanket (Gaymar Industries, Orchard Park, NY); (3) WarmAir and lower body blanket (Cincinnati Sub-Zero Products, Cincinnati, OH); (4) Warm-Gard(R) and lower body blanket (Luis Gibeck AB, Upplands Väsby, Sweden); (5) Warm-Gard and reusable lower body blanket (Luis Gibeck AB); and (6) WarmTouch and lower body blanket (Mallinckrodt Medical Inc., St. Luis, MO). Heat flux and surface temperature were measured with 16 calibrated heat flux transducers. Blanket temperature was measured using 16 thermocouples. DeltaT was varied between -10 and +10 degrees C and h was determined by a linear regression analysis as the slope of DeltaT vs. heat flux. Mean DeltaT was determined for surface temperatures between 36 and 38 degrees C, because similar mean skin temperatures have been found in volunteers. The area covered by the blankets was estimated to be 0.54 m2. Heat transfer from the blanket to the manikin was different for surface temperatures between 36 degrees C and 38 degrees C. At a surface temperature of 36 degrees C the heat transfer was higher (between 13.4 W to 18.3 W) than at surface temperatures of 38 degrees C (8-11.5 W). The highest heat transfer was delivered by the Thermacare system (8.3-18.3 W), the lowest heat transfer was delivered by the Warm-Gard system with the single use blanket (8-13.4 W). The heat exchange coefficient varied between 12.5 W m-2 degrees C-1 and 30.8 W m-2 degrees C-1, mean DeltaT varied between 1.04 degrees C and 2.48 degrees C for surface temperatures of 36 degrees C and between 0.50 degrees C and 1.63 degrees C for surface temperatures of 38 degrees C. No relevant differences in heat transfer of lower body blankets were found between the different forced-air warming systems tested. Heat transfer was lower than heat transfer by upper body blankets tested in a previous study. However, forced-air warming systems with lower body blankets are still more effective than forced-air warming systems with upper body blankets in the prevention of perioperative hypothermia, because they cover a larger area of the body surface.

Pregnancy - identifying fertile days

MedlinePlus

... mean ovulation is near. TAKING YOUR BASAL BODY TEMPERATURE After you ovulate, your body temperature will rise and stay at a higher level ... can use a special thermometer to take your temperature in the morning before you get out of ...

Plasticity of preferred body temperatures as means of coping with climate change?

PubMed Central

Gvoždík, Lumír

2012-01-01

Thermoregulatory behaviour represents an important component of ectotherm non-genetic adaptive capacity that mitigates the impact of ongoing climate change. The buffering role of behavioural thermoregulation has been attributed solely to the ability to maintain near optimal body temperature for sufficiently extended periods under altered thermal conditions. The widespread occurrence of plastic modification of target temperatures that an ectotherm aims to achieve (preferred body temperatures) has been largely overlooked. I argue that plasticity of target temperatures may significantly contribute to an ectotherm's adaptive capacity. Its contribution to population persistence depends on both the effectiveness of acute thermoregulatory adjustments (reactivity) in buffering selection pressures in a changing thermal environment, and the total costs of thermoregulation (i.e. reactivity and plasticity) in a given environment. The direction and magnitude of plastic shifts in preferred body temperatures can be incorporated into mechanistic models, to improve predictions of the impact of global climate change on ectotherm populations. PMID:22072284

Plasticity of preferred body temperatures as means of coping with climate change?

PubMed

Gvozdík, Lumír

2012-04-23

Thermoregulatory behaviour represents an important component of ectotherm non-genetic adaptive capacity that mitigates the impact of ongoing climate change. The buffering role of behavioural thermoregulation has been attributed solely to the ability to maintain near optimal body temperature for sufficiently extended periods under altered thermal conditions. The widespread occurrence of plastic modification of target temperatures that an ectotherm aims to achieve (preferred body temperatures) has been largely overlooked. I argue that plasticity of target temperatures may significantly contribute to an ectotherm's adaptive capacity. Its contribution to population persistence depends on both the effectiveness of acute thermoregulatory adjustments (reactivity) in buffering selection pressures in a changing thermal environment, and the total costs of thermoregulation (i.e. reactivity and plasticity) in a given environment. The direction and magnitude of plastic shifts in preferred body temperatures can be incorporated into mechanistic models, to improve predictions of the impact of global climate change on ectotherm populations.

cAMP signalling in mushroom bodies modulates temperature preference behaviour in Drosophila.

PubMed

Hong, Sung-Tae; Bang, Sunhoe; Hyun, Seogang; Kang, Jongkyun; Jeong, Kyunghwa; Paik, Donggi; Chung, Jongkyeong; Kim, Jaeseob

2008-08-07

Homoiotherms, for example mammals, regulate their body temperature with physiological responses such as a change of metabolic rate and sweating. In contrast, the body temperature of poikilotherms, for example Drosophila, is the result of heat exchange with the surrounding environment as a result of the large ratio of surface area to volume of their bodies. Accordingly, these animals must instinctively move to places with an environmental temperature as close as possible to their genetically determined desired temperature. The temperature that Drosophila instinctively prefers has a function equivalent to the 'set point' temperature in mammals. Although various temperature-gated TRP channels have been discovered, molecular and cellular components in Drosophila brain responsible for determining the desired temperature remain unknown. We identified these components by performing a large-scale genetic screen of temperature preference behaviour (TPB) in Drosophila. In parallel, we mapped areas of the Drosophila brain controlling TPB by targeted inactivation of neurons with tetanus toxin and a potassium channel (Kir2.1) driven with various brain-specific GAL4s. Here we show that mushroom bodies (MBs) and the cyclic AMP-cAMP-dependent protein kinase A (cAMP-PKA) pathway are essential for controlling TPB. Furthermore, targeted expression of cAMP-PKA pathway components in only the MB was sufficient to rescue abnormal TPB of the corresponding mutants. Preferred temperatures were affected by the level of cAMP and PKA activity in the MBs in various PKA pathway mutants.

No Relation between Body Temperature and Arterial Recanalization at Three Days in Patients with Acute Ischaemic Stroke.

PubMed

Geurts, Marjolein; van der Worp, H Bart; Horsch, Alexander D; Kappelle, L Jaap; Biessels, Geert J; Velthuis, Birgitta K

2015-01-01

Recanalization of an occluded intracranial artery is influenced by temperature-dependent enzymes, including alteplase. We assessed the relation between body temperature on admission and recanalization. We included 278 patients with acute ischaemic stroke within nine hours after symptom onset, who had an intracranial arterial occlusion on admission CT angiography, in 13 participating centres. We calculated the relation per every 0.1°Celsius increase in admission body temperature and recanalization at three days. Recanalization occurred in 80% of occluded arteries. There was no relation between body temperature and recanalization at three days after adjustments for age, NIHSS score on admission and treatment with alteplase (adjusted odds ratio per 0.1°Celsius, 0.99; 95% confidence interval, 0.94-1.05; p = 0.70). Results for patients treated or not treated with alteplase were essentially the same. Our findings suggest that in patients with acute ischaemic stroke there is no relation between body temperature on admission and recanalization of an occluded intracranial artery three days later, irrespective of treatment with alteplase.

No Relation between Body Temperature and Arterial Recanalization at Three Days in Patients with Acute Ischaemic Stroke

PubMed Central

Geurts, Marjolein; van der Worp, H. Bart; Horsch, Alexander D.; Kappelle, L. Jaap; Biessels, Geert J.; Velthuis, Birgitta K.

2015-01-01

Background Recanalization of an occluded intracranial artery is influenced by temperature-dependent enzymes, including alteplase. We assessed the relation between body temperature on admission and recanalization. Methods We included 278 patients with acute ischaemic stroke within nine hours after symptom onset, who had an intracranial arterial occlusion on admission CT angiography, in 13 participating centres. We calculated the relation per every 0.1°Celsius increase in admission body temperature and recanalization at three days. Results Recanalization occurred in 80% of occluded arteries. There was no relation between body temperature and recanalization at three days after adjustments for age, NIHSS score on admission and treatment with alteplase (adjusted odds ratio per 0.1°Celsius, 0.99; 95% confidence interval, 0.94–1.05; p = 0.70). Results for patients treated or not treated with alteplase were essentially the same. Conclusions Our findings suggest that in patients with acute ischaemic stroke there is no relation between body temperature on admission and recanalization of an occluded intracranial artery three days later, irrespective of treatment with alteplase. PMID:26473959

[Wireless Passive Body Sensor for Temperature Monitoring Using Near Field Communication Technology].

PubMed

Shi, Bo; Zhang, Li; Zhang, Genxuan; Tsau, Young; Zhang, Sai; Li, Lei

2017-01-01

In this study, we designed a wireless body temperature sensor (WBTS) based on near field communication (NFC) technology. Just attaching the WBTS to a mobile phone with NFC function, the real-time body temperature of human subjects can be acquired by an application program without seperate power supply. The WBTS is mainly composed of a digital body temperature probe (d-BTP), a NFC unit and an antenna. The d-BTP acquires and processes body temperature data through a micro control er, and the NFC unit and antenna are used for wireless energy transmission and data communication between the mobile phone and WBTS. UART communication protocol is used in the communication between the d-BTP and NFC unit, and data compression technique is adopted for improving transmission efficiency and decreasing power loss. In tests, the error of WBTS is ±0.1 oC, in range of 32 oC to 42 oC. The WBTS has advantages of high accuracy, low power loss, strong anti-interference ability, dispensation with independent power supply etc., and it can be integrated into wearable apparatuses for temperature monitoring and health management.

Stability of echogenic liposomes as a blood pool ultrasound contrast agent in a physiologic flow phantom

PubMed Central

Radhakrishnan, Kirthi; Haworth, Kevin J.; Huang, Shao-Ling; Klegerman, Melvin E.; McPherson, David D.; Holland, Christy K.

2016-01-01

Echogenic liposomes (ELIP) are multifunctional ultrasound contrast agents (UCAs) with a lipid shell encapsulating both air and an aqueous core. ELIP are being developed for molecular imaging and image-guided therapeutic delivery. Stability of the echogenicity of ELIP in physiologic conditions is crucial to their successful translation to clinical use. In this study we determined the effects of the surrounding media’s dissolved air concentration, temperature transition and hydrodynamic pressure on the echogenicity of a chemically modified formulation of ELIP to promote stability and echogenicity. ELIP samples were diluted in porcine plasma or whole blood and pumped through a pulsatile flow system with adjustable hydrodynamic pressures and temperature. B-mode images were acquired using a clinical diagnostic scanner every 5 s for a total duration of 75 s. Echogenicity in porcine plasma was assessed as a function of total dissolved gas saturation. ELIP were added to plasma at room temperature (22 °C) or body temperature (37 °C) and pumped through a system maintained at 22 °C or 37 °C to study the effect of temperature transitions on ELIP echogenicity. Echogenicity at normotensive (120/80 mmHg) and hypertensive pressures (145/90 mmHg) was measured. ELIP were echogenic in plasma and whole blood at body temperature under normotensive to hypertensive pressures. Warming of samples from room temperature to body temperature did not alter echogenicity. However, in plasma cooled rapidly from body temperature to room temperature or in degassed plasma, ELIP lost echogenicity within 20 s at 120/80 mmHg. The stability of echogenicity of a modified ELIP formulation was determined in vitro at body temperature, physiologic gas concentration and throughout the physiologic pressure range. However, proper care should be taken to ensure that ELIP are not cooled rapidly from body temperature to room temperature as they will lose their acoustic properties. Further in vivo investigations will be needed to evaluate the optimal usage of ELIP as blood pool contrast agents. PMID:22929652

Evaluation of body temperature in individuals with stroke.

PubMed

Alfieri, Fábio Marcon; Massaro, Ayrton Roberto; Filippo, Thais Raquel; Portes, Leslie Andrews; Battistella, Linamara Rizzo

2017-01-01

A stroke can cause alterations in thermal sensitivity. to verify the conditions of body temperature in hemiplegic patients after stroke as compared to healthy individuals, as well as establish relations between thermal sensitivity and gender, age, Body Mass Index (BMI), plegic side, time after stroke, reports of thermal alterations and the motricity of patients with stroke sequelae. This cross-sectional study included 100 patients (55.6±13 years) with ischemic or hemorrhagic stroke sequelae with unilateral hemiparesis and thirty healthy subjects (55±12.9 years). Individuals with nervous peripheral lesions, diabetes, peripheral vascular diseases or tumors were not included in this study. The volunteers underwent axillary temperature evaluations with the use of a cutaneous thermometer and evaluations of cutaneous temperature of hands and feet as measured by infrared thermography captured by an infrared sensor (ThermaCAMTM SC 500-FLIR Systems). The mean temperature (°C) was analyzed with the SigmaStat 3.5 statistical package. The results have shown that healthy individuals have similar temperatures on either side of the body. The hemiplegic subjects presented a lower temperature on the plegic side and compared to the healthy subjects, both feet of the hemiparetic individuals were colder. The results have also shown that age, body mass index, and the time after stroke have no influence on the alterations in temperature. Regarding the paretic side, individuals with hemiplegia on the right side (right foot) had a lower temperature than those affected on the left side. Motricity was not related to any difference in temperature between the limbs and the reports of temperature differences had no relation with the actual differences found in the study. Healthy individuals have temperature symmetry between between sides of the body, while individuals with stroke sequelae present lower temperature in the paretic side, especially on their feet.

Characterisation of regional skin temperatures in recreational surfers wearing a 2-mm wetsuit.

PubMed

Corona, Luis J; Simmons, Grant H; Nessler, Jeff A; Newcomer, Sean C

2018-05-01

The purpose of this study was to investigate skin temperatures across surfers' bodies while wearing a wetsuit during recreational surfing. Forty-six male recreational surfers participated in this study. Participants were instrumented with eight wireless iButton thermal sensors for the measurement of skin temperature, a Polar RCX5 heart rate monitor and a 2-mm full wetsuit. Following instrumentation, participants were instructed to engage in recreational surfing activities as normal. Significant differences (p < 0.001) in skin temperature (T sk ) were found across the body while wearing a wetsuit during recreational surfing. In addition, regional skin temperature changed across the session for several regions of the body (p < 0.001), and the magnitude of these changes varied significantly between regions. We show for the first time that significant differences exist in skin temperature across the body while wearing a wetsuit during a typical recreational surfing session. These findings may have implications for future wetsuit design. Practitioner Summary: This study investigated the impact of wearing a wetsuit during recreational surfing on regional skin temperatures. Results from this study suggest that skin temperatures differ significantly across the body while wearing a 2-mm wetsuit during recreational surfing. These findings may have implications for future wetsuit design.

The effect of warmed inspired gases on body temperature during arthroscopic shoulder surgery under general anesthesia.

PubMed

Jo, Youn Yi; Kim, Hong Soon; Chang, Young Jin; Yun, Soon Young; Kwak, Hyun Jeong

2013-07-01

Perioperative hypothermia can develop easily during shoulder arthroscopy, because cold irrigation can directly influence core body temperature. The authors investigated whether active warming and humidification of inspired gases reduces falls in core body temperature and allows redistribution of body heat in patients undergoing arthroscopic shoulder surgery under general anesthesia. Patients scheduled for arthroscopic shoulder surgery were randomly assigned to receive either room temperature inspired gases using a conventional respiratory circuit (the control group, n = 20) or inspired gases humidified and heated using a humidified and electrically heated circuit (HHC) (the heated group, n = 20). Core temperatures were significantly lower in both groups from 30 min after anesthesia induction, but were significantly higher in the heated group than in the control group from 75 to 120 min after anesthesia induction. In this study the use of a humidified and electrically heated circuit did not prevent core temperature falling during arthroscopic shoulder surgery, but it was found to decrease reductions in core temperature from 75 min after anesthesia induction.

Deeply torpid bats can change position without elevation of body temperature.

PubMed

Bartonička, Tomáš; Bandouchova, Hana; Berková, Hana; Blažek, Ján; Lučan, Radek; Horáček, Ivan; Martínková, Natália; Pikula, Jiri; Řehák, Zdeněk; Zukal, Jan

2017-01-01

Because body temperature is tightly coupled to physiological function, hibernating animals entering deep torpor are typically immobile. We analysed thermal behaviour and locomotory activity of hibernating greater mouse-eared bats Myotis myotis and found two types of movement behaviour related to body temperature, i.e. movement at high fur temperature and at low fur temperatures (Tflow; <5°C). First Tflow movements appeared at the beginning of March and often occurred during long torpor bouts. In most cases, Tflow events represented slow displacements between clusters of bats. In several cases, however, departure or arrivals from and into clusters was also recorded without any elevation in body temperature. Distance travelled, flight duration and speed of locomotion during Tflow events was lower than in high fur temperature events. Such behaviour could allow bats to save energy long-term and prolong torpor bouts. Tflow movement in torpid bats significantly changes our understanding of basic hibernation principles and we strongly recommend further studies on the subject. Copyright © 2016. Published by Elsevier Ltd.

Links between thermoregulation and aging in endotherms and ectotherms

PubMed Central

Flouris, Andreas D; Piantoni, Carla

2014-01-01

While the link between thermoregulation and aging is generally accepted, much further research, reflection, and debate is required to elucidate the physiological and molecular pathways that generate the observed thermal-induced changes in lifespan. Our aim in this review is to present, discuss, and scrutinize the thermoregulatory mechanisms that are implicated in the aging process in endotherms and ectotherms. Our analysis demonstrates that low body temperature benefits lifespan in both endothermic and ectothermic organisms. Research in endotherms has delved deeper into the physiological and molecular mechanisms linking body temperature and longevity. While research in ectotherms has been steadily increasing during the past decades, further mechanistic work is required in order to fully elucidate the underlying phenomena. What is abundantly clear is that both endotherms and ectotherms have a specific temperature zone at which they function optimally. This zone is defended through both physiological and behavioral means and plays a major role on organismal senescence. That low body temperature may be beneficial for lifespan is contrary to conventional medical theory where reduced body temperature is usually considered as a sign of underlying pathology. Regardless, this phenomenon has been targeted by scientists with the expectation that advancements may compress morbidity, as well as lower disease and mortality risk. The available evidence suggests that lowered body temperature may prolong life span, yet finding the key to temperature regulation remains the problem. While we are still far from a complete understanding of the mechanisms linking body temperature and longevity, we are getting closer. PMID:27226994

Axillary and Tympanic Temperature Measurement in Children and Normal Values for Ages.

PubMed

Oguz, Fatma; Yildiz, Ismail; Varkal, Muhammet Ali; Hizli, Zeynep; Toprak, Sadik; Kaymakci, Kevser; Saygili, Seha Kamil; Kilic, Ayşe; Unuvar, Emin

2018-03-01

The aim of the study was define the normal values of tympanic and axillary body temperature in healthy children. This observational cross-sectional study was performed in healthy children aged 0 to 17 years who visited the ambulatory general pediatric of Istanbul Medical Faculty. Of 1364 children, 651 (47.7%) were girls and 713 were boys, the mean (SD, range) age was 72.5 (53.6, 1-204) months. The mean (SD) axillary body temperature was 36.04°C (0.46°C; minimum, 35.0°C; maximum, 37.6°C). The 95th and 99th percentiles were 36.8°C and 37.0°C, respectively. The mean (SD) tympanic body temperature was 36.91°C (0.46°C; minimum, 35.15°C; maximum, 37.9°C). The 95th and 99th percentiles were 37.6°C and 37.8°C, respectively. There were statistically significant differences between sexes for only tympanic body temperatures. Both axillary and tympanic body temperatures were statistically higher in 0 to 2 months compared with other age groups. For this age group, the 99th percentile was 37.5°C for axillary and 37.85°C for tympanic temperature. Axillary and tympanic body temperatures should be considered as fever when they are more than 37.0°C and 37.8°C, respectively. For 0 to 2 months, fever is 37.5°C and 37.85°C in axillary and tympanic temperatures, respectively.

Changes in cutaneous and body temperature during and after conditioned fear to context in the rat.

PubMed

Vianna, Daniel M L; Carrive, Pascal

2005-05-01

Infrared thermography was used to image changes in cutaneous temperature during a conditioned fear response to context. Changes in heart rate, arterial pressure, activity and body (i.p.) temperature were recorded at the same time by radio-telemetry, in addition to freezing immobility. A marked drop in tail and paws temperature (-5.3 and -7.5 degrees C, respectively, down to room temperature), which lasted for the entire duration of the response (30 min), was observed in fear-conditioned rats. In sham-conditioned rats, the drop was on average half the magnitude and duration. In contrast, temperature of the eye, head and back increased (between + 0.8 and + 1.5 degrees C), with no difference between the two groups of rats. There was a similar increase in body temperature although it was slightly higher and delayed in the fear-conditioned animals. Finally, ending of the fear response was associated with a gradual decrease in body temperature and a rebound increase in the temperature of the tail (+ 3.3 degrees C above baseline). This study shows that fear, and to some extent arousal, evokes a strong cutaneous vasoconstriction that is restricted to the tail and paws. This regionally specific reduction in blood flow may be part of a preparatory response to a possible fight and flight to reduce blood loss in the most exposed parts of the rat's body in case of injury. The data also show that the tail is the main part of the body used for dissipating internal heat accumulated during fear once the animal has returned to a safe environment.

Predicting body temperature and activity of adult Polyommatus icarus using neural network models under current and projected climate scenarios.

PubMed

Howe, P D; Bryant, S R; Shreeve, T G

2007-10-01

We use field observations in two geographic regions within the British Isles and regression and neural network models to examine the relationship between microhabitat use, thoracic temperatures and activity in a widespread lycaenid butterfly, Polyommatus icarus. We also make predictions for future activity under climate change scenarios. Individuals from a univoltine northern population initiated flight with significantly lower thoracic temperatures than individuals from a bivoltine southern population. Activity is dependent on body temperature and neural network models of body temperature are better at predicting body temperature than generalized linear models. Neural network models of activity with a sole input of predicted body temperature (using weather and microclimate variables) are good predictors of observed activity and were better predictors than generalized linear models. By modelling activity under climate change scenarios for 2080 we predict differences in activity in relation to both regional differences of climate change and differing body temperature requirements for activity in different populations. Under average conditions for low-emission scenarios there will be little change in the activity of individuals from central-southern Britain and a reduction in northwest Scotland from 2003 activity levels. Under high-emission scenarios, flight-dependent activity in northwest Scotland will increase the greatest, despite smaller predicted increases in temperature and decreases in cloud cover. We suggest that neural network models are an effective way of predicting future activity in changing climates for microhabitat-specialist butterflies and that regional differences in the thermoregulatory response of populations will have profound effects on how they respond to climate change.

Effect of body temperature on the pharmacokinetics of a triarylmethyl-type paramagnetic contrast agent used in EPR oximetry.

PubMed

Matsumoto, Ken-Ichiro; Hyodo, Fuminori; Mitchell, James B; Krishna, Murali C

2018-02-01

Pharmacokinetics of the tri[8-carboxy-2,2,6,6-tetrakis(2-hydroxymethyl)benzo[1,2-d:4,5-d']bis(1,3)dithio-4-yl]methyl radical (Oxo63) after a single bolus and/or continuous intravenous infusion was investigated in tumor-bearing C3H mice with or without body temperature control while under anesthesia. The in vivo time course of Oxo63 in blood was measured using X-band electron paramagnetic resonance spectroscopy. Distribution of Oxo63 in normal muscle and tumor tissues was obtained using a surface coil resonator and a 700-MHz electron paramagnetic resonance spectrometer. The whole-body distribution of Oxo63 was obtained by 300-MHz continuous-wave electron paramagnetic resonance imaging. The high-resolution 300-MHz time-domain electron paramagnetic resonance imaging was also carried out to probe the distribution of Oxo63. Urination of mice was retarded at low body temperature, causing the concentration of Oxo63 in blood to attain high levels. However, the concentration of Oxo63 in tumor tissue was lower with no control of body temperature than active body temperature control. The nonsystemized blood flow in the tumor tissues may pool Oxo63 at lower body temperature. Pharmacokinetics of the contrast agent were found to be significantly affected by body temperature of the experimental animal, and can influence the probe distribution and the image patterns. Magn Reson Med 79:1212-1218, 2018. © Published 2017. This article is a U.S. Government work and is in the public domain in the USA. © Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

Is body temperature an independent predictor of mortality in hip fracture patients?

PubMed

Faizi, Murtuza; Farrier, Adam J; Venkatesan, Murali; Thomas, Christopher; Uzoigwe, Chika Edward; Balasubramanian, Siva; Smith, Robert P

2014-12-01

Admission body temperature is a critical parameter in all trauma patients. Low admission temperature is strongly associated with adverse outcomes. We have previously shown, in a prospective study that low admission body temperature is common and associated with high mortality in hip fracture patients (Uzoigwe et al., 2014). However, no previous studies have evaluated whether admission temperature is an independent predictor of mortality in hip fracture patients after adjustment for the 7 recognised independent prognostic indicators (Maxwell et al., 2008). We retrospectively collated data on all patients presenting to our institution between June 2011 and February 2013 with a hip fracture. This included patients involved in the original prospective study (Uzoigwe et al., 2014). Admission tympanic temperature, measured on initial presentation at triage, was recorded. The prognosticators of age, gender, source of admission, abbreviated mental test score, haemoglobin, co-morbid disease and the presence or absence of malignancy were also recorded. Using multiple logistic regression, adjustment was made for these potentially confounding prognostic indicators of 30-day mortality, to determine if admission low body temperature were independently linked to mortality. 1066 patients were included. 781 patients, involved in the original prospective study (Uzoigwe et al., 2014), presented in the relevant time frame and were included in the retrospective study. The mean age was 81. There were 273 (26%) men and 793 (74%) women. 407 (38%) had low body temperature (<36.5 °C). Adjustment was made for age, gender, source of admission, abbreviated mental test score, haemoglobin, co-morbid disease and the presence or absence of malignancy. Those with low body temperature had an adjusted odds ratio of 30-day mortality that was 2.1 times that of the euthermic (36.5–37.5 °C). Low body temperature is strongly and independently associated with 30-day mortality in hip fracture patients.

Comparison of rectal and infrared thermometry for obtaining body temperature in cynomolgus macaques (Macaca fascicularis).

PubMed

Sikoski, P; Banks, M L; Gould, R; Young, R W; Wallace, J M; Nader, M A

2007-12-01

It would be clinically advantageous to develop a method of body temperature evaluation in cynomolgus macaques (Macaca fascicularis) that did not require sedation, restraint, surgical manipulation, or expensive equipment. Body temperatures of 51 cynomolgus macaques were taken with rectal thermometry and non-contact infrared thermometry (NIFT) on the shoulder, face, abdomen, and axillary region. Body temperature measurements from NIFT were statistically different (P < 0.0001) from rectal thermometry. In addition, there was greater between- and within-subject variability in values using NIFT. There was no correlation between any sites of the NIFT and rectal thermometry. It was concluded that NIFT was not a valid alternative to rectal thermometry in cynomolgus macaques.

Gigantism, temperature and metabolic rate in terrestrial poikilotherms

PubMed Central

Makarieva, Anastassia M; Gorshkov, Victor G; Li, Bai-Lian

2005-01-01

The mechanisms dictating upper limits to animal body size are not well understood. We have analysed body length data for the largest representatives of 24 taxa of terrestrial poikilotherms from tropical, temperate and polar environments. We find that poikilothermic giants on land become two–three times shorter per each 10 degrees of decrease in ambient temperature. We quantify that this diminution of maximum body size accurately compensates the drop of metabolic rate dictated by lower temperature. This supports the idea that the upper limit to body size within each taxon can be set by a temperature-independent critical minimum value of mass-specific metabolic rate, a fall below which is not compatible with successful biological performance. PMID:16191647

Core and body surface temperatures of nesting leatherback turtles (Dermochelys coriacea).

PubMed

Burns, Thomas J; McCafferty, Dominic J; Kennedy, Malcolm W

2015-07-01

Leatherback turtles (Dermochelys coriacea) are the largest species of marine turtle and the fourth most massive extant reptile. In temperate waters they maintain body temperatures higher than surrounding seawater through a combination of insulation, physiological, and behavioural adaptations. Nesting involves physical activity in addition to contact with warm sand and air, potentially presenting thermal challenges in the absence of the cooling effect of water, and data are lacking with which to understand their nesting thermal biology. Using non-contact methods (thermal imaging and infrared thermometry) to avoid any stress-related effects, we investigated core and surface temperature during nesting. The mean±SE core temperature was 31.4±0.05°C (newly emerged eggs) and was not correlated with environmental conditions on the nesting beach. Core temperature of leatherbacks was greater than that of hawksbill turtles (Eretmochelys imbricata) nesting at a nearby colony, 30.0±0.13°C. Body surface temperatures of leatherbacks showed regional variation, the lateral and dorsal regions of the head were warmest while the carapace was the coolest surface. Surface temperature increased during the early nesting phases, then levelled off or decreased during later phases with the rates of change varying between body regions. Body region, behavioural phase of nesting and air temperature were found to be the best predictors of surface temperature. Regional variation in surface temperature were likely due to alterations in blood supply, and temporal changes in local muscular activity of flippers during the different phases of nesting. Heat exchange from the upper surface of the turtle was dominated by radiative heat loss from all body regions and small convective heat gains to the carapace and front flippers. Copyright © 2015 Elsevier Ltd. All rights reserved.

Evaluation of antipyretic potential of Vernonia cinerea extract in rats.

PubMed

Gupta, Malaya; Mazumder, U K; Manikandan, L; Bhattacharya, S; Haldar, P K; Roy, S

2003-08-01

The methanol extract of the whole plant of Vernonia cinerea (MEVC) was evaluated for its antipyretic potential on normal body temperature and yeast-induced pyrexia in rats. MEVC significantly reduced the normal body temperature at doses of 250 and 500 mg/kg body weight p.o. MEVC also lowered the elevated body temperature in the case of yeast-induced pyrexia in a dose dependent manner. The antipyretic effect of the extract at a dose of 500 mg/kg was identical to that of the standard drug paracetamol. Copyright 2003 John Wiley & Sons, Ltd.

Behavioral thermal tolerances of free-ranging rattlesnakes (Crotalus oreganus) during the summer foraging season.

PubMed

Putman, Breanna J; Clark, Rulon W

2017-04-01

Increasing temperature due to climate change is one of the greatest challenges for wildlife worldwide. Behavioral data on free-ranging individuals is necessary to determine at what temperatures animals modify activity as this would determine their capacity to continue to move, forage, and mate under altered thermal regimes. In particular, high temperatures could limit available surface activity time and time spent on fitness-related activities. Conversely, performance, such as feeding rate, can increase with temperature potentially having positive fitness effects. Here, we examine how the hunting behaviors of free-ranging Northern Pacific Rattlesnakes (Crotalus oreganus) associate with air temperature and body temperature. We continuously recorded snakes in the field using videography, capturing behaviors rarely considered in past studies such as movements in and out of refuge and strikes on prey. We found that as mean daily air temperature increased, hunting activity and the likelihood of hunting at night decreased, while the number of movements and distance moved per day increased. Snakes typically retreated to refuge before body temperatures reached 31°C. Body temperatures of snakes hunting on the surface were lower compared to temperatures of non-hunting snakes in refuge in the morning, while this relationship was inverted in the afternoon. Snake body size influenced the disparity of these temperatures. Finally, strike initiation and success occurred across a wide range of body temperatures, indicating hunting performance may not be strongly constrained by temperature. These results on the temperatures at which free-ranging rattlesnakes exhibit fitness-related behaviors could be valuable for understanding their vulnerabilities to future climates. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of irrigation fluid temperature on body temperature during arthroscopic elbow surgery in dogs.

PubMed

Thompson, K R; MacFarlane, P D

2013-01-01

This prospective randomised clinical trial evaluated the effect of warmed irrigation fluid on body temperature in anaesthetised dogs undergoing arthroscopic elbow surgery. Nineteen dogs undergoing elbow arthroscopy were included in the study and were randomly allocated to one of two groups. Group RT received irrigation fluid at room temperature (RT) while dogs in group W received warmed (W) irrigation fluid (36°C). A standardised patient management and anaesthetic protocol was used and body temperature was measured at four time points; (T1) pre-anaesthetic examination, (T2) arrival into theatre, (T3) end of surgery and (T4) arrival into recovery. There was no significant difference in body temperature at any time point between the groups. The mean overall decrease in body temperature between pre-anaesthetic examination (T1) and return to the recovery suite (T4) was significant in both groups, with a fall of 1.06±0.58°C (p<0.001) in group RT and 1.53±0.76°C (p<0.001) group W. There was no significant difference between the groups. At the end of surgery (T3) 4/19 (21.1%) of dogs were hypothermic (<37°C). The addition of warmed irrigation fluids to a temperature management protocol in dogs undergoing elbow arthroscopy during general anaesthesia did not lead to decreased temperature losses.

Effect of irrigation fluid temperature on body temperature during arthroscopic elbow surgery in dogs

PubMed Central

Thompson, K.R.; MacFarlane, P.D.

2013-01-01

This prospective randomised clinical trial evaluated the effect of warmed irrigation fluid on body temperature in anaesthetised dogs undergoing arthroscopic elbow surgery. Nineteen dogs undergoing elbow arthroscopy were included in the study and were randomly allocated to one of two groups. Group RT received irrigation fluid at room temperature (RT) while dogs in group W received warmed (W) irrigation fluid (36°C). A standardised patient management and anaesthetic protocol was used and body temperature was measured at four time points; (T1) pre-anaesthetic examination, (T2) arrival into theatre, (T3) end of surgery and (T4) arrival into recovery. There was no significant difference in body temperature at any time point between the groups. The mean overall decrease in body temperature between pre-anaesthetic examination (T1) and return to the recovery suite (T4) was significant in both groups, with a fall of 1.06±0.58°C (p<0.001) in group RT and 1.53±0.76°C (p<0.001) group W. There was no significant difference between the groups. At the end of surgery (T3) 4/19 (21.1%) of dogs were hypothermic (<37°C). The addition of warmed irrigation fluids to a temperature management protocol in dogs undergoing elbow arthroscopy during general anaesthesia did not lead to decreased temperature losses. PMID:26623323

Core body temperature as adjunct to endpoint determination in murine median lethal dose testing of rattlesnake venom.

PubMed

Cates, Charles C; McCabe, James G; Lawson, Gregory W; Couto, Marcelo A

2014-12-01

Median lethal dose (LD50) testing in mice is the 'gold standard' for evaluating the lethality of snake venoms and the effectiveness of interventions. As part of a study to determine the murine LD50 of the venom of 3 species of rattlesnake, temperature data were collected in an attempt to more precisely define humane endpoints. We used an 'up-and-down' methodology of estimating the LD50 that involved serial intraperitoneal injection of predetermined concentrations of venom. By using a rectal thermistor probe, body temperature was taken once before administration and at various times after venom exposure. All but one mouse showed a marked, immediate, dose-dependent drop in temperature of approximately 2 to 6°C at 15 to 45 min after administration. The lowest temperature sustained by any surviving mouse was 33.2°C. Surviving mice generally returned to near-baseline temperatures within 2 h after venom administration, whereas mice that did not survive continued to show a gradual decline in temperature until death or euthanasia. Logistic regression modeling controlling for the effects of baseline core body temperature and venom type showed that core body temperature was a significant predictor of survival. Linear regression of the interaction of time and survival was used to estimate temperatures predictive of death at the earliest time point and demonstrated that venom type had a significant influence on temperature values. Overall, our data suggest that core body temperature is a useful adjunct to monitoring for endpoints in LD50 studies and may be a valuable predictor of survival in venom studies.

Synergistic interaction between ketamine and magnesium in lowering body temperature in rats.

PubMed

Vučković, Sonja M; Savić Vujović, Katarina R; Srebro, Dragana P; Medić, Branislava M; Vučetić, Cedomir S; Prostran, Milan Š; Prostran, Milica Š

2014-03-29

A large body of evidence supports the existence of an endogenous glutamate system that tonically modulates body temperature via N-methyl-d-aspartate (NMDA) receptors. Ketamine and magnesium, both NMDA receptor antagonists, are known for their anesthetic, analgesic and anti-shivering properties. This study is aimed at evaluating the effects of ketamine and magnesium sulfate on body temperature in rats, and to determine the type of interaction between them. The body temperature was measured by insertion of a thermometer probe 5cm into the colon of unrestrained male Wistar rats (200-250g). Magnesium sulfate (5 and 60mg/kg, sc) showed influence neither on baseline, nor on morphine-evoked hyperthermic response. Subanesthetic doses of ketamine (5-30mg/kg, ip) given alone, produced significant dose-dependent reduction in both baseline colonic temperature and morphine-induced hyperthermia. Analysis of the log dose-response curves for the effects of ketamine and ketamine-magnesium sulfate combination on the baseline body temperature revealed synergistic interaction, and about 5.3 fold reduction in dosage of ketamine when the drugs were applied in fixed ratio (1:1) combinations. In addition, fixed low dose of magnesium sulfate (5mg/kg, sc) enhanced the temperature lowering effect of ketamine (1.25-10mg/kg, ip) on baseline body temperature and morphine-induced hyperthermia by factors of about 2.5 and 5.3, respectively. This study is the first to demonstrate the synergistic interaction between magnesium sulfate and ketamine in a whole animal study and its statistical confirmation. It is possible that the synergy between ketamine and magnesium may have clinical relevance. Copyright © 2014 Elsevier Inc. All rights reserved.

Comparison of forced-air warming systems with upper body blankets using a copper manikin of the human body.

PubMed

Bräuer, A; English, M J M; Steinmetz, N; Lorenz, N; Perl, T; Braun, U; Weyland, W

2002-09-01

Forced-air warming with upper body blankets has gained high acceptance as a measure for the prevention of intraoperative hypothermia. However, data on heat transfer with upper body blankets are not yet available. This study was conducted to determine the heat transfer efficacy of eight complete upper body warming systems and to gain more insight into the principles of forced-air warming. Heat transfer of forced-air warmers can be described as follows: Qdot;=h. DeltaT. A, where Qdot;= heat flux [W], h=heat exchange coefficient [W m-2 degrees C-1], DeltaT=temperature gradient between the blanket and surface [ degrees C], and A=covered area [m2]. We tested eight different forced-air warming systems: (1) Bair Hugger and upper body blanket (Augustine Medical Inc. Eden Prairie, MN); (2) Thermacare and upper body blanket (Gaymar Industries, Orchard Park, NY); (3) Thermacare (Gaymar Industries) with reusable Optisan upper body blanket (Willy Rüsch AG, Kernen, Germany); (4) WarmAir and upper body blanket (Cincinnati Sub-Zero Products, Cincinnati, OH); (5) Warm-Gard and single use upper body blanket (Luis Gibeck AB, Upplands Väsby, Sweden); (6) Warm-Gard and reusable upper body blanket (Luis Gibeck AB); (7) WarmTouch and CareDrape upper body blanket (Mallinckrodt Medical Inc., St. Luis, MO); and (8) WarmTouch and reusable MultiCover trade mark upper body blanket (Mallinckrodt Medical Inc.) on a previously validated copper manikin of the human body. Heat flux and surface temperature were measured with 11 calibrated heat flux transducers. Blanket temperature was measured using 11 thermocouples. The temperature gradient between the blanket and surface (DeltaT) was varied between -8 and +8 degrees C, and h was determined by linear regression analysis as the slope of DeltaT vs. heat flux. Mean DeltaT was determined for surface temperatures between 36 and 38 degrees C, as similar mean skin surface temperatures have been found in volunteers. The covered area was estimated to be 0.35 m2. Total heat flow from the blanket to the manikin was different for surface temperatures between 36 and 38 degrees C. At a surface temperature of 36 degrees C the heat flows were higher (4-26.6 W) than at surface temperatures of 38 degrees C (2.6-18.1 W). The highest total heat flow was delivered by the WarmTouch trade mark system with the CareDrape trade mark upper body blanket (18.1-26.6 W). The lowest total heat flow was delivered by the Warm-Gard system with the single use upper body blanket (2.6-4 W). The heat exchange coefficient varied between 15.1 and 36.2 W m-2 degrees C-1, and mean DeltaT varied between 0.5 and 3.3 degrees C. We found total heat flows of 2.6-26.6 W by forced-air warming systems with upper body blankets. However, the changes in heat balance by forced-air warming systems with upper body blankets are larger, as these systems are not only transferring heat to the body but are also reducing heat losses from the covered area to zero. Converting heat losses of approximately 37.8 W to heat gain, results in a 40.4-64.4 W change in heat balance. The differences between the systems result from different heat exchange coefficients and different mean temperature gradients. However, the combination of a high heat exchange coefficient with a high mean temperature gradient is rare. This fact offers some possibility to improve these systems.

Brünnich's guillemots (Uria lomvia) maintain high temperature in the body core during dives.

PubMed

Niizuma, Yasuaki; Gabrielsen, Geir W; Sato, Katsufumi; Watanuki, Yutaka; Naito, Yasuhiko

2007-06-01

A major challenge for diving birds, reptiles, and mammals is regulating body temperature while conserving oxygen through a reduction in metabolic processes. To gain insight into how these needs are met, we measured dive depth and body temperatures at the core or periphery between the skin and abdominal muscles simultaneously in freely diving Brünnich's guillemots (Uria lomvia), an arctic seabird, using an implantable data logger (16-mm diameter, 50-mm length, 14-g mass, Little Leonardo Ltd., Tokyo). Guillemots exhibited increased body core temperatures, but decreased peripheral temperatures, during diving. Heat conservation within the body core appeared to result from the combined effect of peripheral vasoconstriction and a high wing beat frequency that generates heat. Conversely, the observed tissue hypothermia in the periphery should reduce metabolic processes as well as heat loss to the water. These physiological effects are likely one of the key physiological adaptations that makes guillemots to perform as an efficient predator in arctic waters.

Effect of a single 3-hour exposure to bright light on core body temperature and sleep in humans.

PubMed

Dijk, D J; Cajochen, C; Borbély, A A

1991-01-02

Seven human subjects were exposed to bright light (BL, approx. 2500 lux) and dim light (DL, approx. 6 lux) during 3 h prior to nocturnal sleep, in a cross-over design. At the end of the BL exposure period core body temperature was significantly higher than at the end of the DL exposure period. The difference in core body temperature persisted during the first 4 h of sleep. The latency to sleep onset was increased after BL exposure. Rapid-eye movement sleep (REMS) and slow-wave sleep (SWS; stage 3 + 4 of non-REMS) were not significantly changed. Eight subjects were exposed to BL from 20.30 to 23.30 h while their eyes were covered or uncovered. During BL exposure with uncovered eyes, core body temperature decreased significantly less than during exposure with covered eyes. We conclude that bright light immediately affects core body temperature and that this effect is mediated via the eyes.

Is Older Colder or Colder Older? The Association of Age With Body Temperature in 18,630 Individuals

PubMed Central

Buxbaum, Joel N.

2011-01-01

In animal studies, caloric restriction resulting in increased longevity is associated with a reduction in body temperature, which is strain specific and likely under genetic control. Small studies in humans have suggested that temperatures may be lower among elderly populations, usually attributed to loss of thermoregulation. We analyzed cross-sectional data from 18,630 white adults aged 20–98 years (mean 58.3 years) who underwent oral temperature measurement as part of a standardized health appraisal at a large U.S. health maintenance organization. Overall, women had higher mean temperatures (97.5 ± 1.2°F) than men (97.2 ± 1.1°F; p < .0001). Mean temperature decreased with age, with a difference of 0.3°F between oldest and youngest groups after controlling for sex, body mass index, and white blood cell count. The results are consistent with low body temperature as a biomarker for longevity. Prospective studies are needed to confirm whether this represents a survival advantage associated with lifetime low steady state temperature. PMID:21324956

Dormancy cues alter insect temperature-size relationships.

PubMed

Clemmensen, Sharon F; Hahn, Daniel A

2015-01-01

Developmental temperatures can have dramatic effects on body size in ectotherms. Thermal plasticity in body size is often viewed in the context of seasonality, but the role of seasonal dormancy responses in generating temperature-size relationships is underappreciated. We used the moth Helicoverpa zea (corn earworm) to examine how photoperiodic seasonal dormancy programming for pupal diapause affects the temperature-size relationship. Specifically, we partition out the contributions of somatic growth versus nutrient storage as fat to the thermal reaction norm for size. With increasing temperature from 16 °C to 20 °C, dormant pupae were both overall larger and progressively fatter than non-dormant pupae. This body mass response is likely driven by concurrent increases in food consumption and longer development times as temperatures increase. Our results demonstrate that seasonal photoperiodic cues can alter temperature-size relationships during pre-dormancy development. For biologists interested in seasonal effects on temperature-size relationships, our results suggest that the key to fully understanding these relationships may lie in integrating multiple seasonal cues and multiple aspects of body size and composition in a nutrient-allocation framework.

78 FR 54731 - Update to the List of Basic Medical Supplies

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-05

... Suture removal kits Syringes Thermometers, mercury for measuring human body temperature Tongue depressors... equipment Orthopedic traction devices and tables Human body positioners including pads, wedges, cradles... staples; and removal kits Tourniquets Thermometers for measuring human body temperature Clinical basins...

Effects of water vapor density on cutaneous resistance to evaporative water loss and body temperature in green tree frogs (Hyla cinerea).

PubMed

Wygoda, Mark L; Kersten, Constance A

2013-01-01

Increased cutaneous resistance to evaporative water loss (Rc) in tree frogs results in decreased water loss rate and increased body temperature. We examined sensitivity of Rc to water vapor density (WVD) in Hyla cinerea by exposing individual frogs and agar models to four different WVD environments and measuring cutaneous evaporative water loss rate and body temperature simultaneously using a gravimetric wind tunnel measuring system. We found that water loss rate varied inversely and body temperature directly with WVD but that models were affected to a greater extent than were animals. Mean Rc was significantly different between the highest WVD environment and each of the three drier environments but did not differ among the drier environments, indicating that Rc initially increases and then reaches a plateau in response to decreasing WVD. Rc was equivalent when calculated using either WVD difference or WVD deficit as the driving force for evaporation. We also directly observed secretions from cutaneous glands while measuring body temperature and tested secretions and skin samples for the presence of lipids. We found that irregular transient body temperature depressions observed during wind tunnel trials occur due to evaporative cooling from intermittent skin secretions containing lipids, although we were unable to identify lipid-secreting glands.

Body temperature and motion: Evaluation of an online monitoring system in pigs challenged with Porcine Reproductive & Respiratory Syndrome Virus.

PubMed

Süli, Tamás; Halas, Máté; Benyeda, Zsófia; Boda, Réka; Belák, Sándor; Martínez-Avilés, Marta; Fernández-Carrión, Eduardo; Sánchez-Vizcaíno, José Manuel

2017-10-01

Highly contagious and emerging diseases cause significant losses in the pig producing industry worldwide. Rapid and exact acquisition of real-time data, like body temperature and animal movement from the production facilities would enable early disease detection and facilitate adequate response. In this study, carried out within the European Union research project RAPIDIA FIELD, we tested an online monitoring system on pigs experimentally infected with the East European subtype 3 Porcine Reproductive & Respiratory Syndrome Virus (PRRSV) strain Lena. We linked data from different body temperature measurement methods and the real-time movement of the pigs. The results showed a negative correlation between body temperature and movement of the animals. The correlation was similar with both body temperature obtaining methods, rectal and thermal sensing microchip, suggesting some advantages of body temperature measurement with transponders compared with invasive and laborious rectal measuring. We also found a significant difference between motion values before and after the challenge with a virulent PRRSV strain. The decrease in motion values was noticeable before any clinical sign was recorded. Based on our results the online monitoring system could represent a practical tool in registering early warning signs of health status alterations, both in experimental and commercial production settings. Copyright © 2017 Elsevier Ltd. All rights reserved.

Reference breast temperature: proposal of an equation.

PubMed

Souza, Gladis Aparecida Galindo Reisemberger de; Brioschi, Marcos Leal; Vargas, José Viriato Coelho; Morais, Keli Cristiane Correia; Dalmaso Neto, Carlos; Neves, Eduardo Borba

2015-01-01

To develop an equation to estimate the breast reference temperature according to the variation of room and core body temperatures. Four asymptomatic women were evaluated for three consecutive menstrual cycles. Using thermography, the temperature of breasts and eyes was measured as indirect reference of core body and room temperatures. To analyze the thermal behavior of the breasts during the cycle, the core body and room temperatures were normalized by means of a mathematical equation. We performed 180 observations and the core temperature had the highest correlation with the breast temperature, followed by room temperature. The proposed prediction model could explain 45.3% of the breast temperature variation, with variable room temperature variable; it can be accepted as a way to estimate the reference breast temperature at different room temperatures. The average breast temperature in healthy women had a direct relation with the core and room temperature and can be estimated mathematically. It is suggested that an equation could be used in clinical practice to estimate the normal breast reference temperature in young women, regardless of the day of the cycle, therefore assisting in evaluation of anatomical studies.

About possibility of temperature trace observing on the human skin using commercially available IR camera

NASA Astrophysics Data System (ADS)

Trofimov, Vyacheslav A.; Trofimov, Vladislav V.; Shestakov, Ivan L.; Blednov, Roman G.

2016-09-01

One of urgent security problems is a detection of objects placed inside the human body. Obviously, for safety reasons one cannot use X-rays for such object detection widely and often. Three years ago, we have demonstrated principal possibility to see a temperature trace, induced by food eating or water drinking, on the human body skin by using a passive THz camera. However, this camera is very expensive. Therefore, for practice it will be very convenient if one can use the IR camera for this purpose. In contrast to passive THz camera using, the IR camera does not allow to see the object under clothing, if an image, produced by this camera, is used directly. Of course, this is a big disadvantage for a security problem solution based on the IR camera using. To overcome this disadvantage we develop novel approach for computer processing of IR camera images. It allows us to increase a temperature resolution of IR camera as well as increasing of human year effective susceptibility. As a consequence of this, a possibility for seeing of a human body temperature changing through clothing appears. We analyze IR images of a person, which drinks water and eats chocolate. We follow a temperature trace on human body skin, caused by changing of temperature inside the human body. Some experiments were made with measurements of a body temperature covered by T-shirt. Shown results are very important for the detection of forbidden objects, cancelled inside the human body, by using non-destructive control without using X-rays.

Whole body cooling by immersion in water at moderate temperatures.

PubMed

Marino, F; Booth, J

1998-06-01

This study investigated the potential use of whole body cooling by water immersion for lowering body temperatures prior to endurance exercise. Rectal temperature (Tre), mean skin temperature (Tsk), oxygen consumption (VO2), and ventilation (VE) were measured in 7 male and 3 female subjects who were immersed in a water bath for up to 60 min. Initial water temperature was 28.8+/-1.5 degrees C and decreased to 23.8+/-1.1 degrees C by the end of immersion. Pre-immersion Tre of 37.34+/-0.36 degrees C was not altered by 60 min water immersion but decreased to 36.64+/-0.34 degrees C at 3 min post immersion (p < 0.01). Tsk decreased from 33.23+/-1.4 degrees C to 26.95+/-1.8 degrees C (p < 0.01) at the end of immersion. Reductions in Tre and Tsk resulted in reduced body heat content (Hc) of approximately 545 kJ (p < 0.01) at the end of immersion. VO2 and VE increased from pre-immersion values of 0.34+/-0.08 L x min(-1) and 6.2+/-1.4 L x min(-1) to 0.54+/-0.09 L x min(-) and 11.5+/-5.4 L x min(-1) at the end of immersion, respectively. Heart rate remained unchanged throughout immersion. These results indicate that whole body immersion in moderately cold water temperatures is an effective cooling maneuver for lowering body temperatures and body Hc in the absence of severe physiological responses generally associated with sudden cold stress.

Daily rhythmicity of body temperature in the dog.

PubMed

Refinetti, R; Piccione, G

2003-08-01

Research over the past 50 years has demonstrated the existence of circadian or daily rhythmicity in the body core temperature of a large number of mammalian species. However, previous studies have failed to identify daily rhythmicity of body temperature in dogs. We report here the successful recording of daily rhythms of rectal temperature in female Beagle dogs. The low robustness of the rhythms (41% of maximal robustness) and the small range of excursion (0.5 degrees C) are probably responsible for previous failures in detecting rhythmicity in dogs.

Device Would Monitor Body Parameters Continuously

NASA Technical Reports Server (NTRS)

Cook, Joseph S., Jr.

1995-01-01

Proposed miniature electronic circuit continuously measures temperature of human subject. Once mounted on subject's skin with medical adhesive tape, electronic thermometer remains in thermal equilibrium with subject's body; thereafter, no need to wait until thermometer reaches body temperature before taking reading. Design provides for switches used to set alarm alerting medical attendants if subject's temperature exceeds critical level. For use on very young child, electronic thermometer sewed into shirt or other suitable garment; device held in contact with skin, and child could not swallow it. Replacement of sensor and computing algorithm changes temperature monitor to cardiorespiratory monitor.

A comparison of hydration effect on body fluid and temperature regulation between Malaysian and Japanese males exercising at mild dehydration in humid heat.

PubMed

Wakabayashi, Hitoshi; Wijayanto, Titis; Lee, Joo-Young; Hashiguchi, Nobuko; Saat, Mohamed; Tochihara, Yutaka

2014-02-04

This study investigated the effect of hydration differences on body fluid and temperature regulation between tropical and temperate indigenes exercising in the heat. Ten Japanese and ten Malaysian males with matched physical characteristics (height, body weight, and peak oxygen consumption) participated in this study. Participants performed exercise for 60 min at 55% peak oxygen uptake followed by a 30-min recovery at 32°C and 70% relative air humidity with hydration (4 times each, 3 mL per kg body weight, 37°C) or without hydration. Rectal temperature, skin temperature, heart rate, skin blood flow, and blood pressure were measured continuously. The percentage of body weight loss and total sweat loss were calculated from body weight measurements. The percentage change in plasma volume was estimated from hemoglobin concentration and hematocrit. Malaysian participants had a significantly lower rectal temperature, a smaller reduction in plasma volume, and a lower heart rate in the hydrated condition than in the non-hydrated condition at the end of exercise (P <0.05), whereas Japanese participants showed no difference between the two hydration conditions. Hydration induced a greater total sweat loss in both groups (P <0.05), and the percentage of body weight loss in hydrated Malaysians was significantly less than in hydrated Japanese (P <0.05). A significant interaction between groups and hydration conditions was observed for the percentage of mean cutaneous vascular conductance during exercise relative to baseline (P <0.05). The smaller reduction in plasma volume and percentage body weight loss in hydrated Malaysians indicated an advantage in body fluid regulation. This may enable Malaysians to reserve more blood for circulation and heat dissipation and thereby maintain lower rectal temperatures in a hydrated condition.

Effects of the TRPV1 antagonist ABT-102 on body temperature in healthy volunteers: pharmacokinetic/pharmacodynamic analysis of three phase 1 trials

PubMed Central

Othman, Ahmed A; Nothaft, Wolfram; Awni, Walid M; Dutta, Sandeep

2013-01-01

Aim To characterize quantitatively the relationship between ABT-102, a potent and selective TRPV1 antagonist, exposure and its effects on body temperature in humans using a population pharmacokinetic/pharmacodynamic modelling approach. Methods Serial pharmacokinetic and body temperature (oral or core) measurements from three double-blind, randomized, placebo-controlled studies [single dose (2, 6, 18, 30 and 40 mg, solution formulation), multiple dose (2, 4 and 8 mg twice daily for 7 days, solution formulation) and multiple-dose (1, 2 and 4 mg twice daily for 7 days, solid dispersion formulation)] were analyzed. nonmem was used for model development and the model building steps were guided by pre-specified diagnostic and statistical criteria. The final model was qualified using non-parametric bootstrap and visual predictive check. Results The developed body temperature model included additive components of baseline, circadian rhythm (cosine function of time) and ABT-102 effect (Emax function of plasma concentration) with tolerance development (decrease in ABT-102 Emax over time). Type of body temperature measurement (oral vs. core) was included as a fixed effect on baseline, amplitude of circadian rhythm and residual error. The model estimates (95% bootstrap confidence interval) were: baseline oral body temperature, 36.3 (36.3, 36.4)°C; baseline core body temperature, 37.0 (37.0, 37.1)°C; oral circadian amplitude, 0.25 (0.22, 0.28)°C; core circadian amplitude, 0.31 (0.28, 0.34)°C; circadian phase shift, 7.6 (7.3, 7.9) h; ABT-102 Emax, 2.2 (1.9, 2.7)°C; ABT-102 EC50, 20 (15, 28) ng ml−1; tolerance T50, 28 (20, 43) h. Conclusions At exposures predicted to exert analgesic activity in humans, the effect of ABT-102 on body temperature is estimated to be 0.6 to 0.8°C. This effect attenuates within 2 to 3 days of dosing. PMID:22966986

Body temperature is elevated and linked to fatigue in relapsing-remitting multiple sclerosis, even without heat exposure.

PubMed

Sumowski, James F; Leavitt, Victoria M

2014-07-01

To investigate whether (1) resting body temperature is elevated in patients with relapsing-remitting multiple sclerosis (RRMS) relative to healthy individuals and patients with secondary progressive multiple sclerosis (SPMS), and (2) warmer body temperature is linked to worse fatigue in patients with RRMS. Cross-sectional study. Climate-controlled laboratory (∼22°C) within a nonprofit medical rehabilitation research center. Patients with RRMS (n=50), matched healthy controls (n=40), and patients with SPMS (n=22). Not applicable. Body temperature was measured with an aural infrared thermometer (normative body temperature for this thermometer, 36.75°C), and differences were compared across patients with RRMS and SPMS and healthy persons. Patients with RRMS completed measures of general fatigue (Fatigue Severity Scale [FSS]), as well as physical and cognitive fatigue (Modified Fatigue Impact Scale [MFIS]). There was a large effect of group (P<.001, ηp(2)=.132) whereby body temperature was higher in patients with RRMS (37.04°±.27°C) relative to healthy controls (36.83°±.33°C; P=.009) and patients with SPMS (36.75°±.39°C; P=.001). Warmer body temperature in patients with RRMS was associated with worse general fatigue (FSS; rp=.315, P=.028) and physical fatigue (physical fatigue subscale of the MFIS; rp=.318, P=.026), but not cognitive fatigue (cognitive fatigue subscale of the MIFS; rp=-.017, P=.909). These are the first-ever demonstrations that body temperature is elevated endogenously in patients with RRMS and linked to worse fatigue. We discuss these findings in the context of failed treatments for fatigue in RRMS, including several failed randomized controlled trials (RCTs) of stimulants (modafinil). In contrast, our findings may help explain how RCTs of cooling garments and antipyretics (aspirin) have effectively reduced MS fatigue, and encourage further research on cooling/antipyretic treatments of fatigue in RRMS. Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Dedicated tool to assess the impact of a rhetorical task on human body temperature.

PubMed

Koprowski, Robert; Wilczyński, Sławomir; Martowska, Katarzyna; Gołuch, Dominik; Wrocławska-Warchala, Emilia

2017-10-01

Functional infrared thermal imaging is a method widely used in medicine, including analysis of the mechanisms related to the effect of emotions on physiological processes. The article shows how the body temperature may change during stress associated with performing a rhetorical task and proposes new parameters useful for dynamic thermal imaging measurements MATERIALS AND METHODS: 29 healthy male subjects were examined. They were given a rhetorical task that induced stress. Analysis and processing of collected body temperature data in a spatial resolution of 256×512pixels and a temperature resolution of 0.1°C enabled to show the dynamics of temperature changes. This analysis was preceded by dedicated image analysis and processing methods RESULTS: The presented dedicated algorithm for image analysis and processing allows for fully automated, reproducible and quantitative assessment of temperature changes and time constants in a sequence of thermal images of the patient. When performing the rhetorical task, the temperature rose by 0.47±0.19°C in 72.41% of the subjects, including 20.69% in whom the temperature decreased by 0.49±0.14°C after 237±141s. For 20.69% of the subjects only a drop in temperature was registered. For the remaining 6.89% of the cases, no temperature changes were registered CONCLUSIONS: The performance of the rhetorical task by the subjects causes body temperature changes. The ambiguous temperature response to the given stress factor indicates the complex mechanisms responsible for regulating stressful situations. Stress associated with the examination itself induces body temperature changes. These changes should always be taken into account in the analysis of infrared data. Copyright © 2017 Elsevier B.V. All rights reserved.

Core body temperature control by total liquid ventilation using a virtual lung temperature sensor.

PubMed

Nadeau, Mathieu; Micheau, Philippe; Robert, Raymond; Avoine, Olivier; Tissier, Renaud; Germim, Pamela Samanta; Vandamme, Jonathan; Praud, Jean-Paul; Walti, Herve

2014-12-01

In total liquid ventilation (TLV), the lungs are filled with a breathable liquid perfluorocarbon (PFC) while a liquid ventilator ensures proper gas exchange by renewal of a tidal volume of oxygenated and temperature-controlled PFC. Given the rapid changes in core body temperature generated by TLV using the lung has a heat exchanger, it is crucial to have accurate and reliable core body temperature monitoring and control. This study presents the design of a virtual lung temperature sensor to control core temperature. In the first step, the virtual sensor, using expired PFC to estimate lung temperature noninvasively, was validated both in vitro and in vivo. The virtual lung temperature was then used to rapidly and automatically control core temperature. Experimentations were performed using the Inolivent-5.0 liquid ventilator with a feedback controller to modulate inspired PFC temperature thereby controlling lung temperature. The in vivo experimental protocol was conducted on seven newborn lambs instrumented with temperature sensors at the femoral artery, pulmonary artery, oesophagus, right ear drum, and rectum. After stabilization in conventional mechanical ventilation, TLV was initiated with fast hypothermia induction, followed by slow posthypothermic rewarming for 1 h, then by fast rewarming to normothermia and finally a second fast hypothermia induction phase. Results showed that the virtual lung temperature was able to provide an accurate estimation of systemic arterial temperature. Results also demonstrate that TLV can precisely control core body temperature and can be favorably compared to extracorporeal circulation in terms of speed.

Measurement of body temperature by use of auricular thermometers versus rectal thermometers in dogs with otitis externa.

PubMed

González, A Michelle; Mann, F A; Preziosi, Diane E; Meadows, Richard L; Wagner-Mann, Colette C

2002-08-01

To compare measurements of body temperature obtained with auricular thermometers versus rectal thermometers in dogs with otitis externa. Prospective study. 100 client-owned dogs: 50 with and 50 without clinical evidence of otitis externa. Dogs were evaluated for the presence of otitis externa on the basis of clinical signs, otoscopic examination, and cytologic evaluation of ear exudate. Auricular and rectal temperatures were obtained simultaneously in all dogs prior to and following ear examination. There was a high correlation between auricular and rectal temperatures in dogs with otitis externa both prior to and after ear manipulation. Significant differences were not detected in temperature measurements among dogs with different degrees of otitis externa. Auricular temperature readings obtained by use of an auricular thermometer in dogs with otitis externa are accurate measurements of body temperature, compared with rectal temperature measurements. Temperature measurements are reliable before and after examination of the ear canal.

Estimation of subsurface thermal structure using sea surface height and sea surface temperature

NASA Technical Reports Server (NTRS)

Kang, Yong Q. (Inventor); Jo, Young-Heon (Inventor); Yan, Xiao-Hai (Inventor)

2012-01-01

A method of determining a subsurface temperature in a body of water is disclosed. The method includes obtaining surface temperature anomaly data and surface height anomaly data of the body of water for a region of interest, and also obtaining subsurface temperature anomaly data for the region of interest at a plurality of depths. The method further includes regressing the obtained surface temperature anomaly data and surface height anomaly data for the region of interest with the obtained subsurface temperature anomaly data for the plurality of depths to generate regression coefficients, estimating a subsurface temperature at one or more other depths for the region of interest based on the generated regression coefficients and outputting the estimated subsurface temperature at the one or more other depths. Using the estimated subsurface temperature, signal propagation times and trajectories of marine life in the body of water are determined.

Determination of time of death in forensic science via a 3-D whole body heat transfer model.

PubMed

Bartgis, Catherine; LeBrun, Alexander M; Ma, Ronghui; Zhu, Liang

2016-12-01

This study is focused on developing a whole body heat transfer model to accurately simulate temperature decay in a body postmortem. The initial steady state temperature field is simulated first and the calculated weighted average body temperature is used to determine the overall heat transfer coefficient at the skin surface, based on thermal equilibrium before death. The transient temperature field postmortem is then simulated using the same boundary condition and the temperature decay curves at several body locations are generated for a time frame of 24h. For practical purposes, curve fitting techniques are used to replace the simulations with a proposed exponential formula with an initial time delay. It is shown that the obtained temperature field in the human body agrees very well with that in the literature. The proposed exponential formula provides an excellent fit with an R 2 value larger than 0.998. For the brain and internal organ sites, the initial time delay varies from 1.6 to 2.9h, when the temperature at the measuring site does not change significantly from its original value. The curve-fitted time constant provides the measurement window after death to be between 8h and 31h if the brain site is used, while it increases 60-95% at the internal organ site. The time constant is larger when the body is exposed to colder air, since a person usually wears more clothing when it is cold outside to keep the body warm and comfortable. We conclude that a one-size-fits-all approach would lead to incorrect estimation of time of death and it is crucial to generate a database of cooling curves taking into consideration all the important factors such as body size and shape, environmental conditions, etc., therefore, leading to accurate determination of time of death. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of methergoline on body temperature in mice.

PubMed

Cardano, C; Strocchi, P; Gonni, D; Walsh, M; Agnati, L F

1977-03-01

Serotonin (5-HT) involvement in body temperature regulation has been studied in mice by means of a 5-HT-selective blocking agent (methergoline). This drug causes an effect on body temperature which is dependent on environmental temperature. At environmental temperatures of 25 degrees C and 11 degrees C methergoline has a hypothermic effect, while at 36 degrees C environmental temperature, methergoline has a hyperthermic effect. At 25 degrees C environmental temperature, the hypothermic effect induced by 125 mug/kg i.p. of methergoline could be antagonized by low doses of LAE-32 (80 mug/kg s.c.), while there was not such an antagonism using higher doses of LAE-32 (100 and 300 mug/kg s.c.). This has been explained using Jalfre's hypothesis of the existence of 5-HT inhibitory and excitatory receptors.

Thermal effects on fish ecology

USGS Publications Warehouse

Coutant, Charles C.

1976-01-01

Of all the environmental factors that influence aquatic organisms, temperature is the most all-pervasive. There is always an environmental temperature while other factors may or may not be present to exert their effects. Fish are, for all practical purposes, thermal conformers, or obligate poikilotherms. That is, they are able to exert little significant influence on maintaining a certain body temperature by specialized metabolic or behavioral means. Their body temperature thus fluctuates nearly in concert with the temperature of their aquatic medium (although particularly large, actively-moving fish such as tuna have deep muscle temperatures slightly higher than the water). Intimate contact at the gills of body fluids with the outside water and the high specific heat of water provide a very efficient heat exchanger that insures this near identity of internal and external temperatures.

Relationships between brain and body temperature, clinical and imaging outcomes after ischemic stroke

PubMed Central

Karaszewski, Bartosz; Carpenter, Trevor K; Thomas, Ralph G R; Armitage, Paul A; Lymer, Georgina Katherine S; Marshall, Ian; Dennis, Martin S; Wardlaw, Joanna M

2013-01-01

Pyrexia soon after stroke is associated with severe stroke and poor functional outcome. Few studies have assessed brain temperature after stroke in patients, so little is known of its associations with body temperature, stroke severity, or outcome. We measured temperatures in ischemic and normal-appearing brain using 1H-magnetic resonance spectroscopy and its correlations with body (tympanic) temperature measured four-hourly, infarct growth by 5 days, early neurologic (National Institute of Health Stroke Scale, NIHSS) and late functional outcome (death or dependency). Among 40 patients (mean age 73 years, median NIHSS 7, imaged at median 17 hours), temperature in ischemic brain was higher than in normal-appearing brain on admission (38.6°C-core, 37.9°C-contralateral hemisphere, P=0.03) but both were equally elevated by 5 days; both were higher than tympanic temperature. Ischemic lesion temperature was not associated with NIHSS or 3-month functional outcome; in contrast, higher contralateral normal-appearing brain temperature was associated with worse NIHSS, infarct expansion and poor functional outcome, similar to associations for tympanic temperature. We conclude that brain temperature is higher than body temperature; that elevated temperature in ischemic brain reflects a local tissue response to ischemia, whereas pyrexia reflects the systemic response to stroke, occurs later, and is associated with adverse outcomes. PMID:23571281

Left caloric vestibular stimulation as a tool to reveal implicit and explicit parameters of body representation.

PubMed

Sedda, A; Tonin, D; Salvato, G; Gandola, M; Bottini, G

2016-04-01

Homeostatic parameters, such as temperature, are related to body representation. In this study, we measured whether caloric vestibular stimulation (CVS) alters body temperature and tactile processing, and if in the direction predicted by a holistic body matrix representation. Skin temperature and tactile two-point discrimination (TPD) acuity were measured for both arms before, immediately after and with a delay from CVS. Participants were also administered a personality questionnaire and an anxiety inventory to rule out confounding factors. Two control experiments were planned to exclude casual variations. Our results show that temperature drops significantly in both arms after CVS. CVS also induces a bilateral improvement in tactile acuity (even though not immediately after but in the delayed condition). Finally, these effects are not due to learning, as demonstrated by the control experiment. In summary, our results suggest that vestibular stimulation updates body representation, supporting the evidence in favor of a body matrix. Copyright © 2016 Elsevier Inc. All rights reserved.

Development of sleep monitoring system for observing the effect of the room ambient toward the quality of sleep

NASA Astrophysics Data System (ADS)

Saad, W. H. M.; Khoo, C. W.; Rahman, S. I. Ab; Ibrahim, M. M.; Saad, N. H. M.

2017-06-01

Getting enough sleep at the right times can help in improving quality of life and protect mental and physical health. This study proposes a portable sleep monitoring device to determine the relationship between the room ambient and quality of sleep. Body condition parameter such as heart rate, body temperature and body movement was used to determine quality of sleep and Audio/video-based monitoring system. The functionality test on all sensors is carried out to make sure that all sensors is working properly. The functionality of the overall system is designed for a better experience with a very minimal intervention to the user. The simple test on the body condition (body temperature and heart rate) while asleep with several different ambient parameters (humidity, brightness and temperature) are varied and the result shows that someone has a better sleep in a dark and colder ambient. This can prove by lower body temperature and lower heart rate.

Locatable-Body Temperature Monitoring Based on Semi-Active UHF RFID Tags

PubMed Central

Liu, Guangwei; Mao, Luhong; Chen, Liying; Xie, Sheng

2014-01-01

This paper presents the use of radio-frequency identification (RFID) technology for the real-time remote monitoring of body temperature, while an associated program can determine the location of the body carrying the respective sensor. The RFID chip's internal integrated temperature sensor is used for both the human-body temperature detection and as a measurement device, while using radio-frequency communication to broadcast the temperature information. The adopted RFID location technology makes use of reference tags together with a nearest neighbor localization algorithm and a multiple-antenna time-division multiplexing location system. A graphical user interface (GUI) was developed for collecting temperature and location data for the data fusion by using RFID protocols. With a puppy as test object, temperature detection and localization experiments were carried out. The measured results show that the applied method, when using a mercury thermometer for comparison in terms of measuring the temperature of the dog, has a good consistency, with an average temperature error of 0.283 °C. When using the associated program over the area of 12.25 m2, the average location error is of 0.461 m, which verifies the feasibility of the sensor-carrier location by using the proposed program. PMID:24675759

Locatable-body temperature monitoring based on semi-active UHF RFID tags.

PubMed

Liu, Guangwei; Mao, Luhong; Chen, Liying; Xie, Sheng

2014-03-26

This paper presents the use of radio-frequency identification (RFID) technology for the real-time remote monitoring of body temperature, while an associated program can determine the location of the body carrying the respective sensor. The RFID chip's internal integrated temperature sensor is used for both the human-body temperature detection and as a measurement device, while using radio-frequency communication to broadcast the temperature information. The adopted RFID location technology makes use of reference tags together with a nearest neighbor localization algorithm and a multiple-antenna time-division multiplexing location system. A graphical user interface (GUI) was developed for collecting temperature and location data for the data fusion by using RFID protocols. With a puppy as test object, temperature detection and localization experiments were carried out. The measured results show that the applied method, when using a mercury thermometer for comparison in terms of measuring the temperature of the dog, has a good consistency, with an average temperature error of 0.283 °C. When using the associated program over the area of 12.25 m2, the average location error is of 0.461 m, which verifies the feasibility of the sensor-carrier location by using the proposed program.

The validity, reliability, and utility of the iButton® for measurement of body temperature circadian rhythms in sleep/wake research.

PubMed

Hasselberg, Michael J; McMahon, James; Parker, Kathy

2013-01-01

Changes in core body temperature due to heat transfer through the skin have a major influence on sleep regulation. Traditional measures of skin temperature are often complicated by extensive wiring and are not practical for use in normal living conditions. This review describes studies examining the reliability, validity and utility of the iButton®, a wireless peripheral thermometry device, in sleep/wake research. A review was conducted of English language literature on the iButton as a measure of circadian body temperature rhythms associated with the sleep/wake cycle. Seven studies of the iButtton as a measure of human body temperature were included. The iButton was found to be a reliable and valid measure of body temperature. Its application to human skin was shown to be comfortable and tolerable with no significant adverse reactions. Distal skin temperatures were negatively correlated with sleep/wake activity, and the temperature gradient between the distal and proximal skin (DPG) was identified as an accurate physiological correlate of sleep propensity. Methodological issues included site of data logger placement, temperature masking factors, and temperature data analysis. The iButton is an inexpensive, wireless data logger that can be used to obtain a valid measurement of human skin temperature. It is a practical alternative to traditional measures of circadian rhythms in sleep/wake research. Further research is needed to determine the utility of the iButton in vulnerable populations, including those with neurodegenerative disorders and memory impairment and pediatric populations. Copyright © 2011 Elsevier B.V. All rights reserved.

The effects of body thermal state on manual performance.

DOT National Transportation Integrated Search

1968-05-01

Thirty-six young men were exposed for 2 hours to environmental temperatures of 10, 26.7, or 46C. Measurements of rectal and skin temperature, heart rate and respiratory rate were made, and average skin and average body temperatures were calculated. M...

Body temperature sensitive micelles for MRI enhancement.

PubMed

Zhu, Xiaolei; Chen, Shizhen; Luo, Qing; Ye, Chaohui; Liu, Maili; Zhou, Xin

2015-06-04

A novel thermo-sensitive micelle contrast agent and its enhancement of MRI contrast with temperature are reported. The morphology changes sharply near 37 °C, resulting in a significant amplification of the CEST signal. This enables detection of small changes in body temperature.

Body Temperatures in the Elderly: A National Study of Physiological, Social, and Environmental Conditions

PubMed Central

Fox, R. H.; Woodward, Patricia M.; Exton-Smith, A. N.; Green, M. F.; Donnison, D. V.; Wicks, M. H.

1973-01-01

Two large-scale surveys of body temperatures in elderly people living at home were carried out in the winter of 1972. Most of the homes visited were cold with room temperatures below the minimum recommended by the Department of Health. Deep body temperatures below 35·5°C were found in 10% of those studied, and the difference between the skin temperature and the core temperature was also reduced in this group. Such individuals are at risk of developing hypothermia since they show evidence of some degree of thermoregulatory failure. Further research is needed, but meanwhile there are practical measures that could be taken to reduce the risk of hypothermia in the elderly. PMID:4686555

Seasonal changes in the body size of two rotifer species living in activated sludge follow the Temperature-Size Rule.

PubMed

Kiełbasa, Anna; Walczyńska, Aleksandra; Fiałkowska, Edyta; Pajdak-Stós, Agnieszka; Kozłowski, Jan

2014-12-01

Temperature-Size Rule (TSR) is a phenotypic body size response of ectotherms to changing temperature. It is known from the laboratory studies, but seasonal patterns in the field were not studied so far. We examined the body size changes in time of rotifers inhabiting activated sludge. We hypothesize that temperature is the most influencing parameter in sludge environment, leading sludge rotifers to seasonally change their body size according to TSR, and that oxygen content also induces the size response. The presence of TSR in Lecane inermis rotifer was tested in a laboratory study with two temperature and two food-type treatments. The effect of interaction between temperature and food was significant; L. inermis followed TSR in one food type only. The seasonal variability in the body sizes of the rotifers L. inermis and Cephalodella gracilis was estimated by monthly sampling and analyzed by multiple regression, in relation to the sludge parameters selected as the most influential by multivariate analysis, and predicted to alter rotifer body size (temperature and oxygen). L. inermis varied significantly in size throughout the year, and this variability is explained by temperature as predicted by the TSR, but not by oxygen availability. C. gracilis also varied in size, though this variability was explained by both temperature and oxygen. We suggest that sludge age acts as a mortality factor in activated sludge. It may have a seasonal effect on the body size of L. inermis and modify a possible effect of oxygen. Activated sludge habitat is driven by both biological processes and human regulation, yet its resident organisms follow general evolutionary rule as they do in other biological systems. The interspecific response patterns differ, revealing the importance of taking species-specific properties into account. Our findings are applicable to sludge properties enhancement through optimizing the conditions for its biological component.

Clumped isotope paleothermometry of eggshells as an indicator of vertebrate endothermy

NASA Astrophysics Data System (ADS)

Canavan, R. R.; Field, D. J.; Therrien, F.; Zelenitsky, D.; Affek, H. P.

2014-12-01

Isotopic analyses of the calcite or aragonite shells of aquatic organisms are often used in the study of the environmental conditions in which they grow; however, this approach is less straightforward in the terrestrial realm, where environments may be more heterogeneous. In such terrestrial localities, the bioapatite of vertebrate teeth comprises the typical archival material for isotopic analyses. The calcitic eggshells of birds and other reptiles may provide suitable material for isotopic analyses that are aimed at studying their physiology and ecology. Here we apply a novel thermometer, carbonate clumped isotopes (Δ47), to test for endothermy in extinct non-avian dinosaurs in the context provided by eggs of modern reptiles and birds. These Δ47-derived temperatures should reflect the temperature of shell formation, which in endothermic animals such as birds should represent the mother's internal body temperature. In ectothermic animals, the same is true although their body temperatures are more affected by the external environment and thus Δ47 temperatures could more accurately describe local environmental temperatures during eggshell formation. Fossil eggshells represent appropriate material for reconstructing internal body temperatures of extinct non-avian dinosaurs since they mineralized within the mother's body, and fragments of eggshell are commonly recovered from dinosaur-bearing fossil deposits. The dimensions of these fragments provide sufficient material for the relatively large sample required for clumped isotope analysis (~20mg). Fossil eggshell samples from several taxa of Late Cretaceous non-avian dinosaurs were analyzed using Δ47 paleothermometry. Textural inspection was used as a first test for diagenetic alteration of the original calcite, and histological indicators were used for broad taxonomic identifications. Preliminary results of Δ47-derived body temperature estimates from eggshells are consistent with previous body temperatures estimates from bioapatite Δ47 analyses performed on non-avian dinosaur teeth.

Ostracod body size trends do not follow either Bergmann's rule or Cope's rule during periods of constant temperature increase

NASA Astrophysics Data System (ADS)

Xu, Y.; Seshadri, P.; Amin, V.; Heim, N. A.; Payne, J.

2013-12-01

Over time, organisms have adapted to changing environments by evolving to be larger or smaller. Scientists have described body-size trends using two generalized theories. Bergmann's rule states that body size is inversely related to temperature, and Cope's rule establishes an increase over time. Cope's rule has been hypothesized as a temporal manifestation of Bergmann's rule, as the temperature of the Earth has consistently decreased over time and mean body size has increased. However, during times of constant temperature increase, Bergmann's rule and Cope's rule predict opposite effects on body size. Our goal was to clarify this relationship using both accessible proxies of historic temperature - atmospheric CO2 levels and paleo-latitude. We measured ostracod lengths throughout the Paleozoic and Mesozoic eras (using the Catalogue of Ostracoda) and utilized ostracod latitudinal information from the Paleobiology Database. By closely studying body-size trends during four time periods of constant CO2 increase across spectrums of time and latitude, we were able to compare the effects of Cope's and Bergmann's rule. The correlation, p-values, and slopes of each of our graphs showed that there is no clear relationship between body size and each of these rules in times of temperature increase, both latitudinally and temporally. Therefore, both Cope's and Bergmann's rule act on marine ostracods and no rule is dominant, though our results more strongly disprove the latitudinal variation in ostracod size.

Long-term calorie restriction, but not endurance exercise, lowers core body temperature in humans

PubMed Central

Soare, Andreea; Cangemi, Roberto; Omodei, Daniela; Holloszy, John O.; Fontana, Luigi

2011-01-01

Reduction of body temperature has been proposed to contribute to the increased lifespan in calorie restricted animals and mice overexpressing the uncoupling protein-2 in hypocretin neurons. However, nothing is known regarding the long-term effects of calorie restriction (CR) with adequate nutrition on body temperature in humans. In this study, 24-hour core body temperature was measured every minute by using ingested telemetric capsules in 24 men and women (mean age 53.7±9.4 yrs) consuming a CR diet for an average of 6 years, 24 age- and sex-matched sedentary (WD) and 24 body fat-matched exercise-trained (EX) volunteers, who were eating Western diets. The CR and EX groups were significantly leaner than the WD group. Energy intake was lower in the CR group (1769±348 kcal/d) than in the WD (2302±668 kcal/d) and EX (2798±760 kcal/d) groups (P<0.0001). Mean 24-hour, day-time and night-time core body temperatures were all significantly lower in the CR group than in the WD and EX groups (P≤0.01). Long-term CR with adequate nutrition in lean and weight-stable healthy humans is associated with a sustained reduction in core body temperature, similar to that found in CR rodents and monkeys. This adaptation is likely due to CR itself, rather than to leanness, and may be involved in slowing the rate of aging. PMID:21483032

Effects of acute temperature change, confinement and housing on plasma corticosterone in water snakes, Nerodia sipedon (Colubridae: Natricinae).

PubMed

Sykes, Kyle Lea; Klukowski, Matthew

2009-03-01

Body temperature affects many aspects of reptilian behavior and physiology, but its effect on hormonal secretion has been little studied, especially in snakes. Major objectives of this study were to determine if acute changes in body temperature during confinement influenced plasma corticosterone levels and if initial body temperatures upon capture in the field were related to baseline corticosterone levels in water snakes (Nerodia sipedon). Water snakes were bled upon capture in the field and after one hour of confinement in a cooled, control, or heated incubator. Since little is known about the potential metabolic changes in response to stress in reptiles, plasma triglyceride levels were also measured. Upon completion of the field study, snakes were housed for 5-8 days without food to determine the effect of chronic stress on both corticosterone and triglyceride levels. Plasma corticosterone concentrations were measured using enzyme-linked immunosorbant assay (ELISA) and plasma triglycerides were determined enzymatically. In the field, experimental alterations of body temperature during confinement had no effect on corticosterone levels. Similarly, there was no correlation between initial body temperature and baseline plasma corticosterone concentrations. However, post-confinement corticosterone levels were approximately three-times greater in females than males. Plasma triglyceride levels were not affected by temperature treatment, confinement, or sex. Compared to field values, both baseline and post-confinement corticosterone levels were elevated after the chronic stress of short-term laboratory housing but triglyceride levels decreased. Overall, these results indicate that sex but not body temperature has a major influence on the adrenocortical stress response in Nerodia sipedon.

Body temperature, activity patterns, and hunting in free-living cheetah: biologging reveals new insights.

PubMed

Hetem, Robyn S; Mitchell, Duncan; de Witt, Brenda A; Fick, Linda G; Maloney, Shane K; Meyer, Leith C R; Fuller, Andrea

2018-05-31

As one of the few felids that is predominantly diurnal, cheetahs (Acinonyx jubatus Von Schreber, 1775) can be exposed to high heat loads in their natural habitat. Little is known about long-term patterns of body temperature and activity (including hunting) in cheetahs because long-term concurrent measurements of body temperature and activity never have been reported for cheetahs, or indeed for any free-living felid. We report here body temperature and locomotor activity measured with implanted data loggers over seven months in five free-living cheetahs in Namibia. Air temperature ranged from a maximum of 39ºC in summer to -2ºC in winter. Cheetahs had higher (∼0.4 ºC) maximum 24h body temperatures, later acrophase (∼1 h), with larger fluctuations in the range of the 24h body temperature rhythm (∼0.4 ºC) during a hot-dry period than during a cool-dry period, but maintained homeothermy irrespective of the climatic conditions. As ambient temperatures increased, the cheetahs shifted from a diurnal to a crepuscular activity pattern, with reduced activity between 9:00 and 15:00 and increased nocturnal activity. The timing of hunts followed the general pattern of activity; the cheetahs hunted when they were on the move. Cheetahs hunted if an opportunity presented itself, on occasion they hunted in the midday heat or in total darkness (new moon). Biologging revealed insights into cheetah biology that are not accessible by traditional observer-based techniques. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Lipid-Emulsion Propofol Less Attenuates the Regulation of Body Temperature than Micro-Emulsion Propofol or Sevoflurane in the Elderly

PubMed Central

Jeong, Cheol Won; Ju, Jin; Lee, Dae Wook; Lee, Seong Heon

2012-01-01

Purpose Anesthesia and surgery commonly cause hypothermia, and this caused by a combination of anesthetic-induced impairment of thermoregulatory control, a cold operation room environment and other factors that promote heat loss. All the general anesthetics markedly impair normal autonomic thermoregulatory control. The aim of this study is to evaluate the effect of two different types of propofol versus inhalation anesthetic on the body temperature. Materials and Methods In this randomized controlled study, 36 patients scheduled for elective laparoscopic gastrectomy were allocated into three groups; group S (sevoflurane, n=12), group L (lipid-emulsion propofol, n=12) and group M (micro-emulsion propofol, n=12). Anesthesia was maintained with typical doses of the study drugs and all the groups received continuous remifentanil infusion. The body temperature was continuously monitored after the induction of general anesthesia until the end of surgery. Results The body temperature was decreased in all the groups. The temperature gradient of each group (group S, group L and group M) at 180 minutes from induction of anesthesia was 2.5±0.6℃, 1.6±0.5℃ and 2.3±0.6℃, respectively. The body temperature of group L was significantly higher than that of group S and group M at 30 minutes and 75 minute after induction of anesthesia, respectively. There were no temperature differences between group S and group M. Conclusion The body temperature is maintained at a higher level in elderly patients anesthetized with lipid-emulsion propofol. PMID:22187253

Circadian variability of body temperature responses to methamphetamine.

PubMed

Behrouzvaziri, Abolhassan; Zaretskaia, Maria V; Rusyniak, Daniel E; Zaretsky, Dmitry V; Molkov, Yaroslav I

2018-01-01

Vital parameters of living organisms exhibit circadian rhythmicity. Although rats are nocturnal animals, most of the studies involving rats are performed during the day. The objective of this study was to examine the circadian variability of the body temperature responses to methamphetamine. Body temperature was recorded in male Sprague-Dawley rats that received intraperitoneal injections of methamphetamine (Meth, 1 or 5 mg/kg) or saline at 10 AM or at 10 PM. The baseline body temperature at night was 0.8°C higher than during the day. Both during the day and at night, 1 mg/kg of Meth induced monophasic hyperthermia. However, the maximal temperature increase at night was 50% smaller than during the daytime. Injection of 5 mg/kg of Meth during the daytime caused a delayed hyperthermic response. In contrast, the same dose at night produced responses with a tendency toward a decrease of body temperature. Using mathematical modeling, we previously showed that the complex dose dependence of the daytime temperature responses to Meth results from an interplay between inhibitory and excitatory drives. In this study, using our model, we explain the suppression of the hyperthermia in response to Meth at night. First, we found that the baseline activity of the excitatory drive is greater at night. It appears partially saturated and thus is additionally activated by Meth to a lesser extent. Therefore, the excitatory component causes less hyperthermia or becomes overpowered by the inhibitory drive in response to the higher dose. Second, at night the injection of Meth results in reduction of the equilibrium body temperature, leading to gradual cooling counteracting hyperthermia.

Lipid-emulsion propofol less attenuates the regulation of body temperature than micro-emulsion propofol or sevoflurane in the elderly.

PubMed

Jeong, Cheol Won; Ju, Jin; Lee, Dae Wook; Lee, Seong Heon; Yoon, Myung Ha

2012-01-01

Anesthesia and surgery commonly cause hypothermia, and this caused by a combination of anesthetic-induced impairment of thermoregulatory control, a cold operation room environment and other factors that promote heat loss. All the general anesthetics markedly impair normal autonomic thermoregulatory control. The aim of this study is to evaluate the effect of two different types of propofol versus inhalation anesthetic on the body temperature. In this randomized controlled study, 36 patients scheduled for elective laparoscopic gastrectomy were allocated into three groups; group S (sevoflurane, n=12), group L (lipid-emulsion propofol, n=12) and group M (micro-emulsion propofol, n=12). Anesthesia was maintained with typical doses of the study drugs and all the groups received continuous remifentanil infusion. The body temperature was continuously monitored after the induction of general anesthesia until the end of surgery. The body temperature was decreased in all the groups. The temperature gradient of each group (group S, group L and group M) at 180 minutes from induction of anesthesia was 2.5 ± 0.6°C, 1.6 ± 0.5°C and 2.3 ± 0.6°C, respectively. The body temperature of group L was significantly higher than that of group S and group M at 30 minutes and 75 minute after induction of anesthesia, respectively. There were no temperature differences between group S and group M. The body temperature is maintained at a higher level in elderly patients anesthetized with lipid-emulsion propofol.

Interindividual variation in thermal sensitivity of maximal sprint speed, thermal behavior, and resting metabolic rate in a lizard.

PubMed

Artacho, Paulina; Jouanneau, Isabelle; Le Galliard, Jean-François

2013-01-01

Studies of the relationship of performance and behavioral traits with environmental factors have tended to neglect interindividual variation even though quantification of this variation is fundamental to understanding how phenotypic traits can evolve. In ectotherms, functional integration of locomotor performance, thermal behavior, and energy metabolism is of special interest because of the potential for coadaptation among these traits. For this reason, we analyzed interindividual variation, covariation, and repeatability of the thermal sensitivity of maximal sprint speed, preferred body temperature, thermal precision, and resting metabolic rate measured in ca. 200 common lizards (Zootoca vivipara) that varied by sex, age, and body size. We found significant interindividual variation in selected body temperatures and in the thermal performance curve of maximal sprint speed for both the intercept (expected trait value at the average temperature) and the slope (measure of thermal sensitivity). Interindividual differences in maximal sprint speed across temperatures, preferred body temperature, and thermal precision were significantly repeatable. A positive relationship existed between preferred body temperature and thermal precision, implying that individuals selecting higher temperatures were more precise. The resting metabolic rate was highly variable but was not related to thermal sensitivity of maximal sprint speed or thermal behavior. Thus, locomotor performance, thermal behavior, and energy metabolism were not directly functionally linked in the common lizard.

Using body temperature, food and water consumption as biomarkers of disease progression in mice with Eμ-myc lymphoma.

PubMed

Hunter, J E; Butterworth, J; Perkins, N D; Bateson, M; Richardson, C A

2014-02-18

Non-invasive biomarkers of disease progression in mice with cancer are lacking making it challenging to implement appropriate humane end points. We investigated whether body temperature, food and water consumption could be used to predict tumour burden. Thirty-six male, wild-type C57Bl/6 mice were implanted with subcutaneous RFID temperature sensors and inoculated with Eμ-myc tumours that infiltrate lymphoid tissue. Decrease in body temperature over the course of the study positively predicted post-mortem lymph node tumour burden (R(2)=0.68, F(1,22)=44.8, P<0.001). At experimental and humane end points, all mice that had a mean decrease in body temperature of 0.7 °C or greater had lymph nodes heavier than 0.5 g (100% sensitivity), whereas a mean decrease in body temperature <0.7 °C always predicted lymph nodes lighter than 0.5 g (100% specificity). The mean decrease in food consumption in each cage also predicted mean post-mortem lymph node tumour burden at 3 weeks (R(2)=0.89, F(1,3)=23.2, P=0.017). Temperature, food and water consumption were useful biomarkers of disease progression in mice with lymphoma and could potentially be used more widely to monitor mice with other forms of cancer.

Seasonal body size reductions with warming covary with major body size gradients in arthropod species.

PubMed

Horne, Curtis R; Hirst, Andrew G; Atkinson, David

2017-03-29

Major biological and biogeographical rules link body size variation with latitude or environmental temperature, and these rules are often studied in isolation. Within multivoltine species, seasonal temperature variation can cause substantial changes in adult body size, as subsequent generations experience different developmental conditions. Yet, unlike other size patterns, these common seasonal temperature-size gradients have never been collectively analysed. We undertake the largest analysis to date of seasonal temperature-size gradients in multivoltine arthropods, including 102 aquatic and terrestrial species from 71 global locations. Adult size declines in warmer seasons in 86% of the species examined. Aquatic species show approximately 2.5-fold greater reduction in size per °C of warming than terrestrial species, supporting the hypothesis that greater oxygen limitation in water than in air forces aquatic species to exhibit greater plasticity in body size with temperature. Total percentage change in size over the annual cycle appears relatively constant with annual temperature range but varies between environments, such that the overall size reduction in aquatic-developing species (approx. 31%) is almost threefold greater than in terrestrial species (approx. 11%). For the first time, we show that strong correlations exist between seasonal temperature-size gradients, laboratory responses and latitudinal-size clines, suggesting that these patterns share common drivers. © 2017 The Author(s).

Assessment of Effectiveness of Cool Coat in Reducing Heat Strain among Workers in Steel Industry.

PubMed

Parameswarappa, S B; Narayana, J

2017-01-01

A research study was conducted to assess the effectiveness of cool coat in reducing heat strain among workers exposed to heat in a steel plant located in south India. The study consists of assessing heat strain of workers exposed to heat in a steel plant by measuring physiological reactions of workers such as pulse rate and core body temperature with and without cool coat. The coal coat taken for this study was procured from M/s Yamuna Industries, Noida. Out of 140 employees exposed to heat hazard, 101 employees were examined in this study. Study was done in important production units in steel plant having heat hazard. Workers were interviewed and examined and information regarding thermal comfort was collected. First, the heat strain was assessed when the workers were not using cool coats. The air temperature was measured at all hot zone workplaces and found in the range of 34 0 C to 39.4 0 C (Mean: 36.54 0 C & S.D: 1.54). Physiological response such as core body temperature, pulse rate and blood pressure of workers exposed to heat hazard were measured before & after work to know the heat strain sustained by workers when they were working. Maximum core body temperature after work was found to be 39.3 0 C (Mean; 38.52 & S.D; 0.7). Maximum pulse rate of workers after work was found to be 120 beats/minute (Mean; 94.96 beats/minute, S.D: 13.11). The study indicate core body temperature of workers was found more than the permissible exposure limit prescribed by ACGIH, indicating the heat strain sustained by workers is significant, whereas the pulse rate and blood pressure was found normal & not exceeded the limits. Second, with cool coat, the heat strain was assessed among 10 workers selected from the 101 employees. Core body temperature was measured before and soon after work, The core body temperature recorded soon after work was in the range of 35.5 - 37.20C (Mean 36.36, SD= 0.52), indicating a drop in the core body temperature. In this study, a core body temperature rise in the range of 1 0 -1.4 0 C was noticed when the employees were not wearing cool coats. Whereas, with the usage of cool coat a rise in core body temperature was not found and in many coat wearing workers a drop in core body temperature (0.2 to 0.9 0 C) was noticed. Employees revealed that the cool coats was comfortable to use and provided the thermal comforts. The study concluded that the cool coat taken for this study was found effective in reducing the heat strain.

Assessment of Effectiveness of Cool Coat in Reducing Heat Strain among Workers in Steel Industry

PubMed Central

Parameswarappa, S. B.; Narayana, J.

2017-01-01

A research study was conducted to assess the effectiveness of cool coat in reducing heat strain among workers exposed to heat in a steel plant located in south India. The study consists of assessing heat strain of workers exposed to heat in a steel plant by measuring physiological reactions of workers such as pulse rate and core body temperature with and without cool coat. The coal coat taken for this study was procured from M/s Yamuna Industries, Noida. Out of 140 employees exposed to heat hazard, 101 employees were examined in this study. Study was done in important production units in steel plant having heat hazard. Workers were interviewed and examined and information regarding thermal comfort was collected. First, the heat strain was assessed when the workers were not using cool coats. The air temperature was measured at all hot zone workplaces and found in the range of 34 0 C to 39.4 0 C (Mean: 36.54 0 C & S.D: 1.54). Physiological response such as core body temperature, pulse rate and blood pressure of workers exposed to heat hazard were measured before & after work to know the heat strain sustained by workers when they were working. Maximum core body temperature after work was found to be 39.3 0 C (Mean; 38.52 & S.D; 0.7). Maximum pulse rate of workers after work was found to be 120 beats/minute (Mean; 94.96 beats/minute, S.D: 13.11). The study indicate core body temperature of workers was found more than the permissible exposure limit prescribed by ACGIH, indicating the heat strain sustained by workers is significant, whereas the pulse rate and blood pressure was found normal & not exceeded the limits. Second, with cool coat, the heat strain was assessed among 10 workers selected from the 101 employees. Core body temperature was measured before and soon after work, The core body temperature recorded soon after work was in the range of 35.5 - 37.20C (Mean 36.36, SD= 0.52), indicating a drop in the core body temperature. In this study, a core body temperature rise in the range of 1 0 -1.4 0 C was noticed when the employees were not wearing cool coats. Whereas, with the usage of cool coat a rise in core body temperature was not found and in many coat wearing workers a drop in core body temperature (0.2 to 0.9 0 C) was noticed. Employees revealed that the cool coats was comfortable to use and provided the thermal comforts. The study concluded that the cool coat taken for this study was found effective in reducing the heat strain. PMID:29391745

Effect of menstrual cycle phase on the ventilatory response to rising body temperature during exercise.

PubMed

Hayashi, Keiji; Kawashima, Takayo; Suzuki, Yuichi

2012-07-01

To examine the effect of menstrual cycle on the ventilatory sensitivity to rising body temperature, ten healthy women exercised for ~60 min on a cycle ergometer at 50% of peak oxygen uptake during the follicular and luteal phases of their cycle. Esophageal temperature, mean skin temperature, mean body temperature, minute ventilation, and tidal volume were all significantly higher at baseline and during exercise in the luteal phase than the follicular phase. On the other hand, end-tidal partial pressure of carbon dioxide was significantly lower during exercise in the luteal phase than the follicular phase. Plotting ventilatory parameters against esophageal temperature revealed there to be no significant menstrual cycle-related differences in the slopes or intercepts of the regression lines, although minute ventilation and tidal volume did significantly differ during exercise with mild hyperthermia. To evaluate the cutaneous vasodilatory response, relative laser-Doppler flowmetry values were plotted against mean body temperature, which revealed that the mean body temperature threshold for cutaneous vasodilation was significantly higher in the luteal phase than the follicular phase, but there were no significant differences in the sensitivity or peak values. These results suggest that the menstrual cycle phase influences the cutaneous vasodilatory response during exercise and the ventilatory response at rest and during exercise with mild hyperthermia, but it does not influence ventilatory responses during exercise with moderate hyperthermia.

Automated measurement of cattle surface temperature and its correlation with rectal temperature

PubMed Central

Ren, Kang; Chen, XiaoLi; Lu, YongQiang; Wang, Dong

2017-01-01

The body temperature of cattle varies regularly with both the reproductive cycle and disease status. Establishing an automatic method for monitoring body temperature may facilitate better management of reproduction and disease control in cattle. Here, we developed an Automatic Measurement System for Cattle’s Surface Temperature (AMSCST) to measure the temperature of metatarsus by attaching a special shell designed to fit the anatomy of cattle’s hind leg. Using AMSCST, the surface temperature (ST) on the metatarsus of the hind leg was successively measured during 24 hours a day with an interval of one hour in three tested seasons. Based on ST and rectal temperature (RT) detected by AMSCST and mercury thermometer, respectively, a linear mixed model was established, regarding both the time point and seasonal factors as the fixed effects. Unary linear correlation and Bland-Altman analysis results indicated that the temperatures measured by AMSCST were closely correlated to those measured by mercury thermometer (R2 = 0.998), suggesting that the AMSCST is an accurate and reliable way to detect cattle’s body temperature. Statistical analysis showed that the differences of STs among the three seasons, or among the different time points were significant (P<0.05), and the differences of RTs among the different time points were similarly significant (P<0.05). The prediction accuracy of the mixed model was verified by 10-fold cross validation. The average difference between measured RT and predicted RT was about 0.10 ± 0.10°C with the association coefficient of 0.644, indicating the feasibility of this model in measuring cattle body temperature. Therefore, an automated technology for accurately measuring cattle body temperature was accomplished by inventing an optimal device and establishing the AMSCST system. PMID:28426682

Core Body Temperature as Adjunct to Endpoint Determination in Murine Median Lethal Dose Testing of Rattlesnake Venom

PubMed Central

Cates, Charles C; McCabe, James G; Lawson, Gregory W; Couto, Marcelo A

2014-01-01

Median lethal dose (LD50) testing in mice is the ‘gold standard’ for evaluating the lethality of snake venoms and the effectiveness of interventions. As part of a study to determine the murine LD50 of the venom of 3 species of rattlesnake, temperature data were collected in an attempt to more precisely define humane endpoints. We used an ‘up-and-down’ methodology of estimating the LD50 that involved serial intraperitoneal injection of predetermined concentrations of venom. By using a rectal thermistor probe, body temperature was taken once before administration and at various times after venom exposure. All but one mouse showed a marked, immediate, dose-dependent drop in temperature of approximately 2 to 6 °C at 15 to 45 min after administration. The lowest temperature sustained by any surviving mouse was 33.2 °C. Surviving mice generally returned to near-baseline temperatures within 2 h after venom administration, whereas mice that did not survive continued to show a gradual decline in temperature until death or euthanasia. Logistic regression modeling controlling for the effects of baseline core body temperature and venom type showed that core body temperature was a significant predictor of survival. Linear regression of the interaction of time and survival was used to estimate temperatures predictive of death at the earliest time point and demonstrated that venom type had a significant influence on temperature values. Overall, our data suggest that core body temperature is a useful adjunct to monitoring for endpoints in LD50 studies and may be a valuable predictor of survival in venom studies. PMID:25527024

Increase in body temperature during migraine attacks.

PubMed

Ordás, Carlos M; Cuadrado, María L; Rodríguez-Cambrón, Ana B; Casas-Limón, Javier; del Prado, Náyade; Porta-Etessam, Jesús

2013-08-01

Intermittent fever has been occasionally related to migraine, either as a migraine equivalent or as a migraine accompaniment. We present a case of recurrent increase in body temperature consistently associated with migraine headaches. A 15-year-old girl reported a 3-year lasting history of migraine without aura, with a feeling of warmth occurring in each episode. Ancillary tests did not show any evidence of secondary headaches or any systemic disease. A 2-month headache diary was obtained, with daily records of headache intensity (0, no headache; 1, mild pain; 2, moderate pain; 3, severe pain) and simultaneous measurements of axillary temperature. Both parameters were registered in the evening, at 6:00 pm every day. The distribution of headache intensity and body temperature as well as the relationship between both variables over time were analyzed with nonparametric tests. The number of days without pain was 28 (45.2%); a mild headache was present on 13 days (21%), a moderate headache on 15 days (24.2%), and a severe headache on 6 days (9.7%). Headache days were associated with higher body temperature than headache-free days (median values: 37.3°C vs 36.6°C; Mann-Whitney U-test, P < 0.001). Moreover, a positive correlation was found between headache intensity and body temperature (Spearman's rho coefficient: 0.83, P < 0.001). Recurrent increase in body temperature may be another manifestation of the complex clinical spectrum of migraine. This symptom is probably related to hypothalamic involvement. Wiley Periodicals, Inc.

About possibility of temperature trace observing on a human skin through clothes by using computer processing of IR image

NASA Astrophysics Data System (ADS)

Trofimov, Vyacheslav A.; Trofimov, Vladislav V.; Shestakov, Ivan L.; Blednov, Roman G.

2017-05-01

One of urgent security problems is a detection of objects placed inside the human body. Obviously, for safety reasons one cannot use X-rays for such object detection widely and often. For this purpose, we propose to use THz camera and IR camera. Below we continue a possibility of IR camera using for a detection of temperature trace on a human body. In contrast to passive THz camera using, the IR camera does not allow to see very pronounced the object under clothing. Of course, this is a big disadvantage for a security problem solution based on the IR camera using. To find possible ways for this disadvantage overcoming we make some experiments with IR camera, produced by FLIR Company and develop novel approach for computer processing of images captured by IR camera. It allows us to increase a temperature resolution of IR camera as well as human year effective susceptibility enhancing. As a consequence of this, a possibility for seeing of a human body temperature changing through clothing appears. We analyze IR images of a person, which drinks water and eats chocolate. We follow a temperature trace on human body skin, caused by changing of temperature inside the human body. Some experiments are made with observing of temperature trace from objects placed behind think overall. Demonstrated results are very important for the detection of forbidden objects, concealed inside the human body, by using non-destructive control without using X-rays.

The effects of co-administration of 3,4-methylenedioxymethamphetamine ("ecstasy") or para-methoxyamphetamine and moclobemide at elevated ambient temperatures on striatal 5-HT, body temperature and behavior in rats.

PubMed

Stanley, N; Salem, A; Irvine, R J

2007-04-25

We have recently demonstrated that co-administration of 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") with the reversible monoamine oxidase type A (MAO-A) inhibitor moclobemide at an ambient temperature of 22 degrees C significantly increases striatal 5-HT outflow and 5-HT-mediated behaviors. In the present study, using microdialysis, we examined the effects of co-administration of MDMA or para-methoxyamphetamine (PMA) with moclobemide on striatal 5-HT outflow at the elevated ambient temperatures of 30 degrees C. Samples were collected every 30 min for 4 h and analyzed by high-performance liquid chromatography assay with electrochemical detection (HPLC-ED). 5-HT-mediated effects on body temperature and behavior were also recorded. Rats were treated with either saline or 20 mg/kg (i.p.) moclobemide, followed by 10 mg/kg (i.p.) MDMA, 10 mg/kg (i.p.) PMA or saline 60 min later. Both MDMA and PMA produced significant increases in 5-HT outflow (370% peak and 309% peak, respectively, P<0.05). MDMA and PMA significantly increased body temperature (+2.0 degrees C and +2.1 degrees C, respectively, P<0.01) and drug-related behaviors (P<0.05). When MDMA or PMA was co-administered with moclobemide, additional significant increases were seen in 5-HT outflow (850% peak, P<0.01 and 1450% peak, P<0.001, respectively) and only MDMA showed additional significant increase in body temperature (+5.0 degrees C, P<0.001). No additional increases were seen in behavioral activity. When moclobemide was co-administered with MDMA, sustained increases in body temperature were recorded that were significantly higher than with MDMA alone and such increases were not observed in our previous study at normal room temperature. Our results suggest greater risk of MDMA-induced adverse effects on body temperature regulation, compared with PMA, when used in combination with moclobemide at elevated ambient temperatures.

In utero heat stress increases postnatal core body temperature in pigs

USDA-ARS?s Scientific Manuscript database

In utero heat stress (IUHS) negatively impacts postnatal development, but how it alters future body temperature parameters and energetic metabolism is not well-understood. Objectives were to characterize future temperature indices and bioenergetic markers in pigs originating from differing in utero...

Human body temperature and new approaches to constructing temperature-sensitive bacterial vaccines

PubMed Central

White, Matthew D.; Bosio, Catharine M.; Duplantis, Barry N.

2012-01-01

Many of the live human and animal vaccines that are currently in use are attenuated by virtue of their temperature-sensitive (TS) replication. These vaccines are able to function because they can take advantage of sites in mammalian bodies that are cooler than the core temperature, where TS vaccines fail to replicate. In this article, we discuss the distribution of temperature in the human body, and relate how the temperature differential can be exploited for designing and using TS vaccines. We also examine how one of the coolest organs of the body, the skin, contains antigen-processing cells that can be targeted to provoke the desired immune response from a TS vaccine. We describe traditional approaches to making TS vaccines, and highlight new information and technologies that are being used to create a new generation of engineered TS vaccines. We pay particular attention to the recently described technology of substituting essential genes from Arctic bacteria for their homologues in mammalian pathogens as a way of creating TS vaccines. PMID:21626408

Human body temperature and new approaches to constructing temperature-sensitive bacterial vaccines.

PubMed

White, Matthew D; Bosio, Catharine M; Duplantis, Barry N; Nano, Francis E

2011-09-01

Many of the live human and animal vaccines that are currently in use are attenuated by virtue of their temperature-sensitive (TS) replication. These vaccines are able to function because they can take advantage of sites in mammalian bodies that are cooler than the core temperature, where TS vaccines fail to replicate. In this article, we discuss the distribution of temperature in the human body, and relate how the temperature differential can be exploited for designing and using TS vaccines. We also examine how one of the coolest organs of the body, the skin, contains antigen-processing cells that can be targeted to provoke the desired immune response from a TS vaccine. We describe traditional approaches to making TS vaccines, and highlight new information and technologies that are being used to create a new generation of engineered TS vaccines. We pay particular attention to the recently described technology of substituting essential genes from Arctic bacteria for their homologues in mammalian pathogens as a way of creating TS vaccines.

Simulated body temperature rhythms reveal the phase-shifting behavior and plasticity of mammalian circadian oscillators.

PubMed

Saini, Camille; Morf, Jörg; Stratmann, Markus; Gos, Pascal; Schibler, Ueli

2012-03-15

The circadian pacemaker in the suprachiasmatic nuclei (SCN) of the hypothalamus maintains phase coherence in peripheral cells through metabolic, neuronal, and humoral signaling pathways. Here, we investigated the role of daily body temperature fluctuations as possible systemic cues in the resetting of peripheral oscillators. Using precise temperature devices in conjunction with real-time monitoring of the bioluminescence produced by circadian luciferase reporter genes, we showed that simulated body temperature cycles of mice and even humans, with daily temperature differences of only 3°C and 1°C, respectively, could gradually synchronize circadian gene expression in cultured fibroblasts. The time required for establishing the new steady-state phase depended on the reporter gene, but after a few days, the expression of each gene oscillated with a precise phase relative to that of the temperature cycles. Smooth temperature oscillations with a very small amplitude could synchronize fibroblast clocks over a wide temperature range, and such temperature rhythms were also capable of entraining gene expression cycles to periods significantly longer or shorter than 24 h. As revealed by genetic loss-of-function experiments, heat-shock factor 1 (HSF1), but not HSF2, was required for the efficient synchronization of fibroblast oscillators to simulated body temperature cycles.

Simulated body temperature rhythms reveal the phase-shifting behavior and plasticity of mammalian circadian oscillators

PubMed Central

Saini, Camille; Morf, Jörg; Stratmann, Markus; Gos, Pascal; Schibler, Ueli

2012-01-01

The circadian pacemaker in the suprachiasmatic nuclei (SCN) of the hypothalamus maintains phase coherence in peripheral cells through metabolic, neuronal, and humoral signaling pathways. Here, we investigated the role of daily body temperature fluctuations as possible systemic cues in the resetting of peripheral oscillators. Using precise temperature devices in conjunction with real-time monitoring of the bioluminescence produced by circadian luciferase reporter genes, we showed that simulated body temperature cycles of mice and even humans, with daily temperature differences of only 3°C and 1°C, respectively, could gradually synchronize circadian gene expression in cultured fibroblasts. The time required for establishing the new steady-state phase depended on the reporter gene, but after a few days, the expression of each gene oscillated with a precise phase relative to that of the temperature cycles. Smooth temperature oscillations with a very small amplitude could synchronize fibroblast clocks over a wide temperature range, and such temperature rhythms were also capable of entraining gene expression cycles to periods significantly longer or shorter than 24 h. As revealed by genetic loss-of-function experiments, heat-shock factor 1 (HSF1), but not HSF2, was required for the efficient synchronization of fibroblast oscillators to simulated body temperature cycles. PMID:22379191

A Pilot Study to Examine Maturation of Body Temperature Control in Preterm Infants

PubMed Central

Knobel, Robin B.; Levy, Janet; Katz, Laurence; Guenther, Bob; Holditch-Davis, Diane

2013-01-01

Objective To test instrumentation and develop analytic models to use in a larger study to examine developmental trajectories of body temperature and peripheral perfusion from birth in extremely low birth weight (EBLW) infants. Design A case study design. Setting The study took place in a level four neonatal intensive care unit (NICU) in North Carolina. Participants Four ELBW infants, less than 29 weeks gestational age at birth. Methods Physiologic data were measured every minute for the first 5 days of life: peripheral perfusion using perfusion index by Masimo and body temperature using thermistors. Body temperature was also measured using infrared thermal imaging. Stimulation and care events were recorded over the first 5 days using video which was coded with Noldus Observer software. Novel analytical models using the state space approach to time series analysis were developed to explore maturation of neural control over central and peripheral body temperature. Results/Conclusion Results from this pilot study confirmed the feasibility of using multiple instruments to measure temperature and perfusion in ELBW infants. This approach added rich data to our case study design and set a clinical context with which to interpret longitudinal physiological data. PMID:24004312

Thermoregulation and temperature relations of alligators and other large ectotherms inhabiting thermally stressed habitats. Progress report, 1 October 1974--30 September 1977

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spotila, J.R.

1977-06-01

Significant progress has been made in determining the mechanisms by which large ectotherms adjust to thermal stress in their natural environment. The effect of mouth gaping on head temperatures and the role of radiation, conduction and convection on body temperatures of alligators have been determined. The utility of energy budget modeling as a method for studying the thermoregulatory mechanisms of animals has been demonstrated. Steady state and time dependent models of body temperature have been tested. Convection coefficients and evaporative water loss rates have been measured for the turtle, Chysemys scripta. Climate space diagrams have been formulated and are beingmore » tested. Behavioral thermoregulation of turtles has been studied in PAR pond on the Savannah River Plant, Aiken, S.C. Steady state energy budget equations have been computed for largemouth bass. Experimental heat transfer coefficients indicate that most heat transfer is through the body wall and not via the gills. A time dependent model is being tested. It predicts the body temperature of a fish in a heterothermal environment. Theoretical calculations have been made of the effects of body size, color, and metabolism on the temperature regulation of ectotherms.« less

Modeling energetic and theoretical costs of thermoregulatory strategy.

PubMed

Alford, John G; Lutterschmidt, William I

2012-01-01

Poikilothermic ectotherms have evolved behaviours that help them maintain or regulate their body temperature (T (b)) around a preferred or 'set point' temperature (T (set)). Thermoregulatory behaviors may range from body positioning to optimize heat gain to shuttling among preferred microhabitats to find appropriate environmental temperatures. We have modelled movement patterns between an active and non-active shuttling behaviour within a habitat (as a biased random walk) to investigate the potential cost of two thermoregulatory strategies. Generally, small-bodied ectotherms actively thermoregulate while large-bodied ectotherms may passively thermoconform to their environment. We were interested in the potential energetic cost for a large-bodied ectotherm if it were forced to actively thermoregulate rather than thermoconform. We therefore modelled movements and the resulting and comparative energetic costs in precisely maintaining a T (set) for a small-bodied versus large-bodied ectotherm to study and evaluate the thermoregulatory strategy.

Homeostasis and biological rhythms in the rat during spaceflight

NASA Technical Reports Server (NTRS)

Fuller, C. A.

1985-01-01

The effects of microgravity on the physiological regulation of homeostatic systems is studied. The temperature and heart rate of rats exposed to seven days of microgravity and a 12:12 light/dark cycle are analyzed. A 24-hour nocturnal rhythmicity is observed in the control and in-flight heart rates and body temperatures. The preflight daytime body temperature was calculated as 37.2 + or - 0.03 C and in-flight as 37.4 + or 0.04 C; nighttime body temperature preflight daytime was determined as 38.0 + or - 0.02 C, and in-flight as 37.8 + or 0.06 C. The 24-hour mean heart rate was depressed from 412 + or - 3.3 bpm preflight to 373 + or - 2.4 bpm in-flight; this change is noted in both dark and light conditions. It is detected that microgravity alters the steady state regulation of heart rate and body temperature.

Physiological mechanisms of thermoregulation in reptiles: a review.

PubMed

Seebacher, Frank; Franklin, Craig E

2005-11-01

The thermal dependence of biochemical reaction rates means that many animals regulate their body temperature so that fluctuations in body temperature are small compared to environmental temperature fluctuations. Thermoregulation is a complex process that involves sensing of the environment, and subsequent processing of the environmental information. We suggest that the physiological mechanisms that facilitate thermoregulation transcend phylogenetic boundaries. Reptiles are primarily used as model organisms for ecological and evolutionary research and, unlike in mammals, the physiological basis of many aspects in thermoregulation remains obscure. Here, we review recent research on regulation of body temperature, thermoreception, body temperature set-points, and cardiovascular control of heating and cooling in reptiles. The aim of this review is to place physiological thermoregulation of reptiles in a wider phylogenetic context. Future research on reptilian thermoregulation should focus on the pathways that connect peripheral sensing to central processing which will ultimately lead to the thermoregulatory response.

Environmental Heat Stress Among Young Working Women: A Pilot Study.

PubMed

Rahman, Juma; Fakhruddin, S H M; Rahman, A K M Fazlur; Halim, M A

Heat waves are increasing significantly in frequency and severity and threaten the health and income of outdoor workers. Pregnant women workers are particularly at risk due to their delicate physiological systems and accountabilities to future generations. Animal and human studies propose that elevated body temperatures during pregnancy can induce adverse pregnancy outcomes. To measure the change in internal body temperature (Tcore) in young working women before, after, and during work (both outdoor and indoor) on hot humid days and relate threshold temperature to the upshot adverse effects of pregnancy (teratogenicity and related miscarriage). Tympanic temperatures were measured using infrared ear thermometers and workplace temperatures were collected using Lascar Data Logger. Brief exploratory interviews were conducted to gather qualitative data, and content analysis was also carried out. Body temperatures were found elevated among outdoor women workers compared with that of indoor women workers. The present study found that outdoor work during pregnancy in hot, humid days might increase body temperature up to levels that could induce fetal destruction or anomaly. Copyright © 2016 Icahn School of Medicine at Mount Sinai. Published by Elsevier Inc. All rights reserved.

Seasonal variability and influence of outdoor temperature on body temperature of cardiac arrest victims.

PubMed

Stratil, Peter; Wallmueller, Christian; Schober, Andreas; Stoeckl, Mathias; Hoerburger, David; Weiser, Christoph; Testori, Christoph; Krizanac, Danica; Spiel, Alexander; Uray, Thomas; Sterz, Fritz; Haugk, Moritz

2013-05-01

Mild therapeutic hypothermia is a major advance in post-resuscitation-care. Some questions remain unclear regarding the time to initiate cooling and the time to achieve target temperature below 34 °C. We examined whether seasonal variability of outside temperature influences the body temperature of cardiac arrest victims, and if this might have an effect on outcome. Patients with witnessed out-of-hospital cardiac arrests were enrolled retrospectively. Temperature variables from 4 climatic stations in Vienna were provided from the Central Institute for Meteorology and Geodynamics. Depending on the outside temperature at the scene the study participants were assigned to a seasonal group. To compare the seasonal groups a Student's t-test or Mann-Whitney U test was performed as appropriate. Of 134 patients, 61 suffered their cardiac arrest during winter, with an outside temperature below 10 °C; in 39 patients the event occurred during summer, with an outside temperature above 20 °C. Comparing the tympanic temperature recorded at hospital admission, the median of 36 °C (IQR 35.3-36.3) during summer differed significantly to winter with a median of 34.9 °C (IQR 34-35.6) (p<0.05). This seasonal alterations in core body temperature had no impact on the time-to-target-temperature, survival rate or neurologic recovery. The seasonal variability of outside temperature influences body temperature of out-of-hospital cardiac arrest victims. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Lower core body temperature and greater body fat are components of a human thrifty phenotype.

PubMed

Reinhardt, M; Schlögl, M; Bonfiglio, S; Votruba, S B; Krakoff, J; Thearle, M S

2016-05-01

In small studies, a thrifty human phenotype, defined by a greater 24-hour energy expenditure (EE) decrease with fasting, is associated with less weight loss during caloric restriction. In rodents, models of diet-induced obesity often have a phenotype including a reduced EE and decreased core body temperature. We assessed whether a thrifty human phenotype associates with differences in core body temperature or body composition. Data for this cross-sectional analysis were obtained from 77 individuals participating in one of two normal physiology studies while housed on our clinical research unit. Twenty-four-hour EE using a whole-room indirect calorimeter and 24-h core body temperature were measured during 24 h each of fasting and 200% overfeeding with a diet consisting of 50% carbohydrates, 20% protein and 30% fat. Body composition was measured by dual X-ray absorptiometry. To account for the effects of body size on EE, changes in EE were expressed as a percentage change from 24-hour EE (%EE) during energy balance. A greater %EE decrease with fasting correlated with a smaller %EE increase with overfeeding (r=0.27, P=0.02). The %EE decrease with fasting was associated with both fat mass and abdominal fat mass, even after accounting for covariates (β=-0.16 (95% CI: -0.26, -0.06) %EE per kg fat mass, P=0.003; β=-0.0004 (-0.0007, -0.00004) %EE kg(-1) abdominal fat mass, P=0.03). In men, a greater %EE decrease in response to fasting was associated with a lower 24- h core body temperature, even after adjusting for covariates (β=1.43 (0.72, 2.15) %EE per 0.1 °C, P=0.0003). Thrifty individuals, as defined by a larger EE decrease with fasting, were more likely to have greater overall and abdominal adiposity as well as lower core body temperature consistent with a more efficient metabolism.

Glutamatergic Preoptic Area Neurons That Express Leptin Receptors Drive Temperature-Dependent Body Weight Homeostasis.

PubMed

Yu, Sangho; Qualls-Creekmore, Emily; Rezai-Zadeh, Kavon; Jiang, Yanyan; Berthoud, Hans-Rudolf; Morrison, Christopher D; Derbenev, Andrei V; Zsombok, Andrea; Münzberg, Heike

2016-05-04

The preoptic area (POA) regulates body temperature, but is not considered a site for body weight control. A subpopulation of POA neurons express leptin receptors (LepRb(POA) neurons) and modulate reproductive function. However, LepRb(POA) neurons project to sympathetic premotor neurons that control brown adipose tissue (BAT) thermogenesis, suggesting an additional role in energy homeostasis and body weight regulation. We determined the role of LepRb(POA) neurons in energy homeostasis using cre-dependent viral vectors to selectively activate these neurons and analyzed functional outcomes in mice. We show that LepRb(POA) neurons mediate homeostatic adaptations to ambient temperature changes, and their pharmacogenetic activation drives robust suppression of energy expenditure and food intake, which lowers body temperature and body weight. Surprisingly, our data show that hypothermia-inducing LepRb(POA) neurons are glutamatergic, while GABAergic POA neurons, originally thought to mediate warm-induced inhibition of sympathetic premotor neurons, have no effect on energy expenditure. Our data suggest a new view into the neurochemical and functional properties of BAT-related POA circuits and highlight their additional role in modulating food intake and body weight. Brown adipose tissue (BAT)-induced thermogenesis is a promising therapeutic target to treat obesity and metabolic diseases. The preoptic area (POA) controls body temperature by modulating BAT activity, but its role in body weight homeostasis has not been addressed. LepRb(POA) neurons are BAT-related neurons and we show that they are sufficient to inhibit energy expenditure. We further show that LepRb(POA) neurons modulate food intake and body weight, which is mediated by temperature-dependent homeostatic responses. We further found that LepRb(POA) neurons are stimulatory glutamatergic neurons, contrary to prevalent models, providing a new view on thermoregulatory neural circuits. In summary, our study significantly expands our current understanding of central circuits and mechanisms that modulate energy homeostasis. Copyright © 2016 the authors 0270-6474/16/365034-13$15.00/0.

Glutamatergic Preoptic Area Neurons That Express Leptin Receptors Drive Temperature-Dependent Body Weight Homeostasis

PubMed Central

Qualls-Creekmore, Emily; Rezai-Zadeh, Kavon; Jiang, Yanyan; Berthoud, Hans-Rudolf; Morrison, Christopher D.; Derbenev, Andrei V.; Zsombok, Andrea

2016-01-01

The preoptic area (POA) regulates body temperature, but is not considered a site for body weight control. A subpopulation of POA neurons express leptin receptors (LepRbPOA neurons) and modulate reproductive function. However, LepRbPOA neurons project to sympathetic premotor neurons that control brown adipose tissue (BAT) thermogenesis, suggesting an additional role in energy homeostasis and body weight regulation. We determined the role of LepRbPOA neurons in energy homeostasis using cre-dependent viral vectors to selectively activate these neurons and analyzed functional outcomes in mice. We show that LepRbPOA neurons mediate homeostatic adaptations to ambient temperature changes, and their pharmacogenetic activation drives robust suppression of energy expenditure and food intake, which lowers body temperature and body weight. Surprisingly, our data show that hypothermia-inducing LepRbPOA neurons are glutamatergic, while GABAergic POA neurons, originally thought to mediate warm-induced inhibition of sympathetic premotor neurons, have no effect on energy expenditure. Our data suggest a new view into the neurochemical and functional properties of BAT-related POA circuits and highlight their additional role in modulating food intake and body weight. SIGNIFICANCE STATEMENT Brown adipose tissue (BAT)-induced thermogenesis is a promising therapeutic target to treat obesity and metabolic diseases. The preoptic area (POA) controls body temperature by modulating BAT activity, but its role in body weight homeostasis has not been addressed. LepRbPOA neurons are BAT-related neurons and we show that they are sufficient to inhibit energy expenditure. We further show that LepRbPOA neurons modulate food intake and body weight, which is mediated by temperature-dependent homeostatic responses. We further found that LepRbPOA neurons are stimulatory glutamatergic neurons, contrary to prevalent models, providing a new view on thermoregulatory neural circuits. In summary, our study significantly expands our current understanding of central circuits and mechanisms that modulate energy homeostasis. PMID:27147656

Effect of paracetamol (acetaminophen) on body temperature in acute stroke: A meta-analysis.

PubMed

Fang, Junjie; Chen, Chensong; Cheng, Hongsen; Wang, Ren; Ma, Linhao

2017-10-01

The objective of this study was to assess the efficacy of paracetamol (acetaminophen) on body temperature in acute stroke. Medline, Cochrane Central Register of Controlled Trials, EMBASE, Chinese BioMedical Literature Database, China National Knowledge Infrastructure, and the World Health Organization (WHO) International Clinical Trials Registry Platform were searched electronically. Relevant journals and references of studies included were hand-searched for randomized controlled trials (RCT) and controlled clinical trials (CCT) regarding the efficacy of paracetamol (acetaminophen) on body temperature in acute stroke. Two reviewers independently performed data extraction and quality assessment. Data were analyzed using RevMan 5.3 software by the Cochrane Collaboration. Five studies were included. To compare the efficacy of paracetamol (acetaminophen) in acute stroke, the pooled RR (Risk Ratio) and its 95% CI of body temperature reduction at 24h from the start of treatment were -0.3 (95% CI: -0.52 to -0.08), with statistical significance (P=0.007). Consistently, the pooled RR (Risk Ratio) and its 95% CI of body temperature at 24h from the start of treatment were -0.22 (-0.29, -0.15), with statistical significance (P<0.00001). When analyzing the body temperature reduction after 5days from the start of treatment, the pooled RR (Risk Ratio) and its 95% CI were 0.04 (95% CI: -0.20 to 0.29), with no statistical significance (P=0.73). For functional outcome (mRS≤2) analysis, the pooled RR and its 95% CI were 1.08 (0.88, 1.32), with no statistical significance (P=0.45). In addition, the difference of serious adverse events between acetaminophen and placebo was 0.86 (95% CI: 0.62 to 1.2), with no statistical significance (P=0.27). Acetaminophen was revealed to have some favorable influence in body temperature reduction in acute stroke, but showed no important effect on improving functional outcome and reducing adverse events of patients. What is already known on this subject? Paracetamol (acetaminophen) is one of the most commonly used antipyretic drugs and has some capability to reduce body temperature through acting on central nervous system. Acetaminophen showed some capability to decrease body temperature for acute stroke. Acetaminophen could not improve functional outcome and reduce adverse events of patients with acute stroke. Copyright © 2017 Elsevier Inc. All rights reserved.

Association of low body temperature and poor outcomes in patients admitted with worsening heart failure: a substudy of the Efficacy of Vasopressin Antagonism in Heart Failure Outcome Study with Tolvaptan (EVEREST) trial.

PubMed

Payvar, Saeed; Spertus, John A; Miller, Alan B; Casscells, S Ward; Pang, Peter S; Zannad, Faiez; Swedberg, Karl; Maggioni, Aldo P; Reid, Kimberly J; Gheorghiade, Mihai

2013-12-01

Risk stratification in patients admitted with worsening heart failure (HF) is essential for tailoring therapy and counselling. Risk models are available but rarely used, in part because many require laboratory and imaging results that are not routinely available. Body temperature is associated with prognosis in other illnesses, and we hypothesized that low body temperature would be associated with worse outcomes in patients admitted with worsening HF. The Efficacy of Vasopressin Antagonism in Heart Failure Outcome Study with Tolvaptan (EVEREST) trial was an event-driven, randomized, double-blind, placebo-controlled study of tolvaptan in 4133 patients hospitalized for worsening HF with an EF <40%. Co-primary endpoints were all-cause mortality and cardiovascular (CV) death or HF rehospitalization. Body temperature was measured orally at randomization and entered in analyses both as a continuous variable and categorized into three groups (<36 °C, 36-36.5 °C, and >36.5 °C) using Cox regression models. The composite of CV death or HF rehospitalization occurred in 1544 patients within 1 year. For every 1 °C decrease in body temperature, the risk of adverse outcomes increased by 16% [hazard raio (HR) 1.16, 95% confidence interval (CI) 1.04-1.28], after adjustment for age, gender, race, systolic blood pressure, EF, blood urea nitrogen, and serum sodium. In fully adjusted analysis, the risk of adverse outcomes in the lowest body temperature group (<36 °C) was 51% higher than that of the index group (>36.5 °C) (HR 1.35, 95% CI 1.15-1.58). Low body temperature is an independent marker of poor cardiovascular outcomes in patients admitted with worsening HF and reduced EF.

The correlation between the amplitude of Osborn wave and core body temperature.

PubMed

Omar, Hesham R; Camporesi, Enrico M

2015-08-01

Several reports illustrate an inverse correlation between the Osborn wave (J wave) amplitude and core body temperature. We attempted to study the strength of this correlation. We reviewed all articles reporting hypothermic J waves from 1950-2014 for patient demographics, core body temperature in Celsius (°C), amplitude of the J wave in millimeters (mm), lead with the highest amplitude of J wave, presence of acidosis, PO2, electrolytes and outcome. In cases with more than one electrocardiogram (ECG), the respective core body temperature and J wave amplitude of each ECG were recorded. The main study outcome is to evaluate the correlation between the J wave amplitude and core body temperature in the admission ECG. We have also examined the strength of this relationship in cases with more than one ECG. We attempted to find the most frequent lead that recorded the highest amplitude of the J wave in addition to the correlation between the amplitude of J wave and pH. We found 64 articles comprising a total of 68 cases. When analyzing only cases with more than one reported ECG, there was a strong inverse correlation (r = - 0.682, p<0.001) between J wave amplitude and body temperature: however, when analyzing admission ECG of all cases, the correlation was only moderate (r = - 0.410, p<0.001). The lead with the highest amplitude of the J wave was V4 (44% of the cases, p<0.001) followed by V3 (23.7% of the cases, p<0.001). The amplitude of the J wave in the admission ECG of hypothermic patients may not accurately predict the core body temperature. © The European Society of Cardiology 2014.

Vertebrate blood cell volume increases with temperature: implications for aerobic activity.

PubMed

Gillooly, James F; Zenil-Ferguson, Rosana

2014-01-01

Aerobic activity levels increase with body temperature across vertebrates. Differences in these levels, from highly active to sedentary, are reflected in their ecology and behavior. Yet, the changes in the cardiovascular system that allow for greater oxygen supply at higher temperatures, and thus greater aerobic activity, remain unclear. Here we show that the total volume of red blood cells in the body increases exponentially with temperature across vertebrates, after controlling for effects of body size and taxonomy. These changes are accompanied by increases in relative heart mass, an indicator of aerobic activity. The results point to one way vertebrates may increase oxygen supply to meet the demands of greater activity at higher temperatures.

Heat Stress Monitor

NASA Technical Reports Server (NTRS)

1994-01-01

The heavy, cumbersome body protection suits worn by members of hazardous materials response teams cause marked elevation of body temperatures, which can reduce effectiveness and lead to heat stress and injury. The CorTemp System, marketed by Human Technologies, Inc., provides the basis for a body temperature monitoring alarm system. Encased in a three-quarter-inch ingestible capsule, the system includes a mini-thermometer, miniature telemetry system, a microbattery and temperature sensor. It makes its way through the digestive system, continuously monitoring temperature. Findings are sent to the recorder by telemetry, and then displayed and stored for transfer to a computer.

[The development of a respiration and temperature monitor].

PubMed

Du, X; Wu, B; Liu, Y; He, Q; Xiao, J

2001-12-01

This paper introduces the design of a monitoring system to measure the respiration and temperature of a body with an 8Xc196 single-chip microcomputer. This system can measure and display the respiration wave, respiration frequency and the body temperature in real-time with a liquid crystal display (LCD) and give an alarm when the parameters are beyond the normal scope. In addition, this device can provide a 24 hours trend graph of the respiration frequency and the body temperature parameters measured. Data can also be exchanged through serial communication interfaces (RS232) between the PC and the monitor.

Heart rate, body temperature and physical activity are variously affected during insulin treatment in alloxan-induced type 1 diabetic rat.

PubMed

Howarth, F C; Jacobson, M; Shafiullah, M; Ljubisavljevic, M; Adeghate, E

2011-01-01

Diabetes mellitus is associated with a variety of cardiovascular complications including impaired cardiac muscle function. The effects of insulin treatment on heart rate, body temperature and physical activity in the alloxan (ALX)-induced diabetic rat were investigated using in vivo biotelemetry techniques. The electrocardiogram, physical activity and body temperature were recorded in vivo with a biotelemetry system for 10 days before ALX treatment, for 20 days following administration of ALX (120 mg/kg) and thereafter, for 15 days whilst rats received daily insulin. Heart rate declined rapidly after administration of ALX. Pre-ALX heart rate was 321+/-9 beats per minute, falling to 285+/-12 beats per minute 15-20 days after ALX and recovering to 331+/-10 beats per minute 5-10 days after commencement of insulin. Heart rate variability declined and PQ, QRS and QT intervals were prolonged after administration of ALX. Physical activity and body temperature declined after administration of ALX. Pre-ALX body temperature was 37.6+/-0.1 °C, falling to 37.3+/-0.1 °C 15-20 days after ALX and recovering to 37.8+/-0.1 °C 5-10 days after commencement insulin. ALX-induced diabetes is associated with disturbances in heart rhythm, physical activity and body temperature that are variously affected during insulin treatment.

Recent Advances in Thermoregulation

ERIC Educational Resources Information Center

Tansey, Etain A.; Johnson, Christopher D.

2015-01-01

Thermoregulation is the maintenance of a relatively constant core body temperature. Humans normally maintain a body temperature at 37°C, and maintenance of this relatively high temperature is critical to human survival. This concept is so important that control of thermoregulation is often the principal example cited when teaching physiological…

Baby sleeping bag and conventional bedding conditions--comparative investigations by infrared thermography.

PubMed

Sauseng, W; Kerbl, R; Thaller, S; Hanzer, M; Zotter, H

2011-09-01

Thermal stress is a risk factor for sudden infant death syndrome (SIDS). Recently, baby sleeping bags have been recommended as a preventive measure against SIDS. The aim of this study was to describe in which way the use of baby sleeping bags might influence thermoregulation of sleeping infants and maybe the incidence of SIDS. Body surface temperature was recorded by use of infrared thermography in 15 infants (median age 49 days). Recordings were done twice: after sleeping for 60 min under a blanket and after sleeping for 60 min in a baby sleeping bag. Temperature was recorded and compared for defined sites of body surface. Infants' mean body surface temperature as well as core temperature after sleeping in a baby sleeping bag did not show significant differences when compared to infants sleeping under a conventional blanket. Under controlled conditions, core temperature and mean body surface temperature are comparable, equally if using a baby sleeping bag or conventional bedding. However, under the more uncontrolled conditions of baby care at home, sleeping bags might provide a more constant temperature profile, while other bedding conditions may lead to significant variations of temperature pattern. © Georg Thieme Verlag KG Stuttgart · New York.

Both Low Temperature and Shorter Duration of Food Availability Delay Testicular Regression and Affect the Daily Cycle in Body Temperature in a Songbird.

PubMed

Dawson, Alistair

Photoperiodic control of reproduction in birds is based on two processes, a positive effect leading to gonadal maturation and an inhibitory effect subsequently inducing regression. Nonphotoperiodic cues can modulate photoperiodic control, particularly the inhibitory process. In previous studies of common starlings (Sturnus vulgaris), (1) restriction of food availability to 8 h after dawn had little effect on testicular maturation but dramatically delayed subsequent regression and (2) lower ambient temperature also had little effect during maturation but delayed regression. Could the effects of food restriction and temperature share a common underlying mechanism? Four groups of starlings were kept on a simulated natural cycle in photoperiod in a 2 × 2 factorial experimental design. Two groups were held under an ambient temperature of 16°C, and the other two were held under 6°C. One of each of these groups had food provided ad lib., and in the other two groups access to food was denied 7 h after dawn. In both the ad lib. food groups and the food-restricted groups, lower temperature had little effect on testicular maturation but delayed subsequent regression and molt. In both the 16°C groups and the 6°C groups, food restriction had no effect on testicular maturation but delayed regression and molt. The daily cycle in body temperature was recorded in all groups when the photoperiod had reached 12L∶12D, the photoperiod at which regression is initiated. In both 6°C groups, nighttime body temperature was lower than in the 16°C groups, a characteristic of shorter photoperiods. In the two ad lib. food groups high daytime temperature was maintained until dusk, whereas in the two food-restricted groups body temperature began to decrease after food withdrawal. Thus, both lower temperature and food restriction delayed regression, as if the photoperiod was shorter than it actually was, and both resulted in daily cycles in body temperature that reflected cycles under shorter photoperiods. This implies that the daily cycle in body temperature is possibly a common pathway through which nonphotoperiodic cues may operate.

Effect of a warm footbath before bedtime on body temperature and sleep in older adults with good and poor sleep: an experimental crossover trial.

PubMed

Liao, Wen-Chun; Wang, Lee; Kuo, Ching-Pyng; Lo, Chyi; Chiu, Ming-Jang; Ting, Hua

2013-12-01

The decrease in core body temperature before sleep onset and during sleep is associated with dilation of peripheral blood vessels, which permits heat dissipation from the body core to the periphery. A lower core temperature coupled with a higher distal (hands and feet) temperature before sleep are associated with shorter sleep latency and better sleep quality. A warm footbath is thought to facilitate heat dissipation to improve sleep outcomes. This study examined the effect of a warm footbath (40°C water temperature, 20-min duration) on body temperature and sleep in older adults (≥55 years) with good and poor sleep. Two groups and an experimental crossover design was used. Forty-three adults responded to our flyer and 25 participants aged 59.8±3.7 years (poor sleeper with a Pittsburgh Sleep Quality Index score≥5=17; good sleepers with a Pittsburgh Sleep Quality Index score<5=8) completed this study. All participants had body temperatures (core, abdomen, and foot) and polysomnography recorded for 3 consecutive nights. The first night was for adaptation and sleep apnea screening. Participants were then randomly assigned to either the structured foot bathing first (second night) and non-bathing second (third night) condition or the non-bathing first (second night) and foot bathing second (third night) condition. A footbath before sleep significantly increased and retained foot temperatures in both good and poor sleepers. The pattern of core temperatures during foot bathing was gradually elevated (poor sleepers vs. good sleepers=+0.40±0.58°C vs. +0.66±0.17°C). There were no significant changes in polysomnographic sleep and perceived sleep quality between non-bathing and bathing nights for both groups. A footbath of 40°C water temperature and 20-min duration before sleep onset increases foot temperatures and distal-proximal skin temperature gradients to facilitate vessel dilatation and elevates core temperature to provide heat load to the body. This footbath does not alter sleep in older adults with good and poor sleep. Copyright © 2013 Elsevier Ltd. All rights reserved.

Stability of echogenic liposomes as a blood pool ultrasound contrast agent in a physiologic flow phantom.

PubMed

Radhakrishnan, Kirthi; Haworth, Kevin J; Huang, Shao-Ling; Klegerman, Melvin E; McPherson, David D; Holland, Christy K

2012-11-01

Echogenic liposomes (ELIP) are multifunctional ultrasound contrast agents (UCAs) with a lipid shell encapsulating both air and an aqueous core. ELIP are being developed for molecular imaging and image-guided therapeutic delivery. Stability of the echogenicity of ELIP in physiologic conditions is crucial to their successful translation to clinical use. In this study, we determined the effects of the surrounding media's dissolved air concentration, temperature transition and hydrodynamic pressure on the echogenicity of a chemically modified formulation of ELIP to promote stability and echogenicity. ELIP samples were diluted in porcine plasma or whole blood and pumped through a pulsatile flow system with adjustable hydrodynamic pressures and temperature. B-mode images were acquired using a clinical diagnostic scanner every 5 s for a total duration of 75 s. Echogenicity in porcine plasma was assessed as a function of total dissolved gas saturation. ELIP were added to plasma at room temperature (22 °C) or body temperature (37 °C) and pumped through a system maintained at 22 °C or 37 °C to study the effect of temperature transitions on ELIP echogenicity. Echogenicity at normotensive (120/80 mmHg) and hypertensive pressures (145/90 mmHg) was measured. ELIP were echogenic in plasma and whole blood at body temperature under normotensive to hypertensive pressures. Warming of samples from room temperature to body temperature did not alter echogenicity. However, in plasma cooled rapidly from body temperature to room temperature or in degassed plasma, ELIP lost echogenicity within 20 s at 120/80 mmHg. The stability of echogenicity of a modified ELIP formulation was determined in vitro at body temperature, physiologic gas concentration and throughout the physiologic pressure range. However, proper care should be taken to ensure that ELIP are not cooled rapidly from body temperature to room temperature as they will lose their echogenic properties. Further in vivo investigations will be needed to evaluate the optimal usage of ELIP as blood pool contrast agents. Copyright © 2012 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Reference breast temperature: proposal of an equation

PubMed Central

de Souza, Gladis Aparecida Galindo Reisemberger; Brioschi, Marcos Leal; Vargas, José Viriato Coelho; Morais, Keli Cristiane Correia; Dalmaso, Carlos; Neves, Eduardo Borba

2015-01-01

ABSTRACT Objective To develop an equation to estimate the breast reference temperature according to the variation of room and core body temperatures. Methods Four asymptomatic women were evaluated for three consecutive menstrual cycles. Using thermography, the temperature of breasts and eyes was measured as indirect reference of core body and room temperatures. To analyze the thermal behavior of the breasts during the cycle, the core body and room temperatures were normalized by means of a mathematical equation. Results We performed 180 observations and the core temperature had the highest correlation with the breast temperature, followed by room temperature. The proposed prediction model could explain 45.3% of the breast temperature variation, with variable room temperature variable; it can be accepted as a way to estimate the reference breast temperature at different room temperatures. Conclusion The average breast temperature in healthy women had a direct relation with the core and room temperature and can be estimated mathematically. It is suggested that an equation could be used in clinical practice to estimate the normal breast reference temperature in young women, regardless of the day of the cycle, therefore assisting in evaluation of anatomical studies. PMID:26761549

Thermal maps of young women and men

NASA Astrophysics Data System (ADS)

Chudecka, Monika; Lubkowska, Anna

2015-03-01

The objective was to use thermal imaging (ThermaCAM SC500) as an effective tool in establishing a thermal map of young participants, with a high diagnostic value for medicine, physiotherapy and sport. A further aim was to establish temperature distributions and ranges on the body surface of the young women and men as standard temperatures for the examined age group, taking into account BMI, body surface area and selected parameters of body fat distribution. The participants included young, healthy and physically active women (n = 100) and men (n = 100). In the women and men, the highest Tmean temperatures were found on the trunk. The warmest were the chest and upper back, then the lower back and abdomen. The lowest Tmean were found in the distal parts of the body, especially on the lower limbs. The results showed that only in the area of the chest was Tmean significantly higher in women than in men. In the areas of the hands (front and back) Tmean were similar for women and men. In the other analyzed body surface areas, Tmean were significantly lower in women. Research showed significant differences in body surface temperature between the women and men. Among the analyzed characteristics, Tmean in the chest, upper back, abdomen, lower back (both in women and men) were mainly correlated with BMI and PBF; the correlations were negative. Difficulties in interpreting changes in temperature in selected body areas in people with various conditions can be associated with the lack of studies on large and representative populations of healthy individuals with normal weight/height parameters. Therefore, it seems that this presented research is a significant practical and cognitive contribution to knowledge on thermoregulation, and may therefore be used as a reference for other studies using thermal imaging in the evaluation of changes in body surface temperatures.

Assessment of body mapping sportswear using a manikin operated in constant temperature mode and thermoregulatory model control mode

NASA Astrophysics Data System (ADS)

Wang, Faming; Del Ferraro, Simona; Molinaro, Vincenzo; Morrissey, Matthew; Rossi, René

2014-09-01

Regional sweating patterns and body surface temperature differences exist between genders. Traditional sportswear made from one material and/or one fabric structure has a limited ability to provide athletes sufficient local wear comfort. Body mapping sportswear consists of one piece of multiple knit structure fabric or of different fabric pieces that may provide athletes better wear comfort. In this study, the `modular' body mapping sportswear was designed and subsequently assessed on a `Newton' type sweating manikin that operated in both constant temperature mode and thermophysiological model control mode. The performance of the modular body mapping sportswear kit and commercial products were also compared. The results demonstrated that such a modular body mapping sportswear kit can meet multiple wear/thermal comfort requirements in various environmental conditions. All body mapping clothing (BMC) presented limited global thermophysiological benefits for the wearers. Nevertheless, BMC showed evident improvements in adjusting local body heat exchanges and local thermal sensations.

Assessment of body mapping sportswear using a manikin operated in constant temperature mode and thermoregulatory model control mode.

PubMed

Wang, Faming; Del Ferraro, Simona; Molinaro, Vincenzo; Morrissey, Matthew; Rossi, René

2014-09-01

Regional sweating patterns and body surface temperature differences exist between genders. Traditional sportswear made from one material and/or one fabric structure has a limited ability to provide athletes sufficient local wear comfort. Body mapping sportswear consists of one piece of multiple knit structure fabric or of different fabric pieces that may provide athletes better wear comfort. In this study, the 'modular' body mapping sportswear was designed and subsequently assessed on a 'Newton' type sweating manikin that operated in both constant temperature mode and thermophysiological model control mode. The performance of the modular body mapping sportswear kit and commercial products were also compared. The results demonstrated that such a modular body mapping sportswear kit can meet multiple wear/thermal comfort requirements in various environmental conditions. All body mapping clothing (BMC) presented limited global thermophysiological benefits for the wearers. Nevertheless, BMC showed evident improvements in adjusting local body heat exchanges and local thermal sensations.

Sleep-wake responses of squirrel monkeys exposed to hyperdynamic environments

NASA Technical Reports Server (NTRS)

Fuller, C. A.

1983-01-01

This study examines the sleep responses of primates to acute 3 Gz environments. To investigate this question, loosely-restrained squirrel monkeys were exposed to 70 minutes of 3 Gz during the day. The animals' behavioral state was polygraphically monitored (EEG, EMG, EOG) along with video and deep body temperature. During the control period, animals exhibited slow wave sleep (SWS) napping behavior. SWS occurred during approximately 20 percent of the control period. Body temperature was maintained at 38.7 C. At 3 Gz, SWS was inhibited for 5 minutes, after which SWS occurred at levels 50 percent lower than in the control period. During the post-centrifugation period, SWS was elevated above the control (50 percent) and hyperdynamic (100 percent) levels. Body temperature was depressed 1.5 C when the animals were at 3 Gz. Thus, hyperdynamic environments are capable of modifying primate sleep behavior, at least as a result of acute exposure. Further, the increased arousal in the hyperdynamic environment is correlated with a lower body temperature. This negative correlation differs from the normal positive correlation of arousal and body temperature.

Comparison of 2 protocols to increase circulating progesterone concentration before timed artificial insemination in lactating dairy cows with or without elevated body temperature.

PubMed

Pereira, M H C; Wiltbank, M C; Guida, T G; Lopes, F R; Vasconcelos, J L M

2017-10-01

Two treatments designed to increase circulating progesterone concentration (P4) during preovulatory follicle development were compared. One treatment used 2 intravaginal P4 implants (controlled internal drug-releasing inserts; CIDR) and the other used a GnRH treatment at beginning of the protocol. Lactating Holstein cows that had been diagnosed as nonpregnant were randomly assigned to receive timed artificial insemination (TAI) following 1 of 2 treatments (n = 1,638 breedings): (1) GnRH: CIDR+ 2 mg of estradiol (E2) benzoate + 100 µg of GnRH on d -11, PGF 2α on d -4, CIDR withdrawal + 1.0 mg of E2-cypionate + PGF 2α ) on d -2, and TAI on d 0; or (2) 2CIDR: 2 CIDR + 2 mg of E2-benzoate on d -11, 1 CIDR withdrawn + PGF 2α on d -4, second CIDR withdrawn + 1.0 mg of E2-cypionate + PGF 2α on d -2, and TAI on d 0. Milk yield was measured daily between d 0 and d 7. Rectal temperature was measured using a digital thermometer at d 0 and 7, and elevated body temperature was defined as an average rectal temperature ≥39.1°C. Pregnancy diagnoses were performed on d 32 and 60 after TAI. We detected no effect of treatments on pregnancy per AI or pregnancy loss regardless of elevated body temperature, body condition score, parity, milk yield, or presence or absence of a corpus luteum (CL) on d -11 or d -4. Pregnancy per AI at 60 d was reduced [elevated body temperature = 22.8% (162/709), no elevated body temperature 34.1% (279/817)] and pregnancy loss tended to increase [elevated body temperature = 20.2% (41/203), no elevated body temperature 14.4% (47/326)] in cows with elevated body temperature. Various physiological measurements associated with greater fertility were also reduced in cows with elevated body temperature, such as percentage of cows with a CL at PGF 2α (decreased 7.9%), ovulatory follicle diameter (decreased 0.51 mm), expression of estrus (decreased 5.1%), and ovulation near TAI (decreased 2.8%) compared with cows without elevated body temperature. A greater proportion of cows (30.2%) had a CL at PGF 2α in the GnRH treatment [74.1% (570/763)] than in the 2CIDR treatment [56.9% (434/763)]; however, circulating P4 concentration was greater at the time of PGF 2α treatment (d -4) for cows 2CIDR (4.26 ± 0.13 ng/mL) than in cows in GnRH (3.99 ± 0.14 ng/mL). Thus, these 2 protocols yield similar fertility results that might be due to somewhat different physiological alterations. Treatment with GnRH increased the proportion of cows with a CL at PGF 2α ; however, the 2CIDR protocol increased circulating P4 under all circumstances. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Keep the brain cool--endovascular cooling in patients with severe traumatic brain injury: a case series study.

PubMed

Fischer, Marlene; Lackner, Peter; Beer, Ronny; Helbok, Raimund; Klien, Stephanie; Ulmer, Hanno; Pfausler, Bettina; Schmutzhard, Erich; Broessner, Gregor

2011-04-01

As brain temperature is reported to be extensively higher than core body temperature in traumatic brain injury (TBI) patients, posttraumatic hyperthermia is of particular relevance in the injured brain. To study the influence of prophylactic normothermia on brain temperature and the temperature gradient between brain and core body in patients with severe TBI using an intravascular cooling system and to assess the relationship between brain temperature and intracranial pressure (ICP) under endovascular temperature control. Prospective case series study conducted in the neurologic intensive care unit of a tertiary care university hospital. Seven patients with severe TBI with a Glasgow Coma Scale score of 8 or less were consecutively enrolled. Prophylactic normothermia, defined as a target temperature of 36.5°C, was maintained using an intravascular cooling system. Simultaneous measurements of brain and urinary bladder temperature and ICP were taken over a 72-hour period. The mean bladder temperature in normothermic patients was 36.3 ± 0.4°C, and the mean brain temperature was determined as 36.4 ± 0.5°C. The mean temperature difference between brain and bladder was 0.1°C. We found a significant direct correlation between brain and bladder temperature (r = 0.95). In 52.4% of all measurements, brain temperature was higher than core body temperature. The mean ICP was 18 ± 8 mm Hg. Intravascular temperature management stabilizes both brain and body core temperature; prophylactic normothermia reduces the otherwise extreme increase of intracerebral temperature in patients with severe TBI. The intravascular cooling management proved to be an efficacious and feasible method to control brain temperature and to avoid hyperthermia in the injured brain. We could not find a statistically significant correlation between brain temperature and ICP.

Changes in body temperature.

PubMed

2010-03-01

People over the age of 60 have, on average, a lower temperature than the accepted 'normal' value of 37°C. There is also less variability in temperature, which means that older people may have little fever response to severe infection. People with cognitive impairment may have either higher or lower temperature; this may be due to loss of appropriate behavioural response to changes in temperature. Those with Alzheimer's disease sometimes have a modest increase in core body temperature, suggesting that change in basic metabolic rate may be responsible.

Tympanic ear thermometer assessment of body temperature among patients with cognitive disturbances. An acceptable and ethically desirable alternative?

PubMed

Aadal, Lena; Fog, Lisbet; Pedersen, Asger Roer

2016-12-01

Investigation of a possible relation between body temperature measurements by the current generation of tympanic ear and rectal thermometers. In Denmark, a national guideline recommends the rectal measurement. Subsequently, the rectal thermometers and tympanic ear devices are the most frequently used and first choice in Danish hospital wards. Cognitive changes constitute challenges with cooperating in rectal temperature assessments. With regard to diagnosing, ethics, safety and the patients' dignity, the tympanic ear thermometer might comprise a desirable alternative to rectal noninvasive measurement of body temperature during in-hospital-based neurorehabilitation. A prospective, descriptive cohort study. Consecutive inclusion of 27 patients. Linear regression models were used to analyse 284 simultaneous temperature measurements. Ethical approval for this study was granted by the Danish Data Protection Agency, and the study was completed in accordance with the Helsinki Declaration 2008. About 284 simultaneous rectal and ear temperature measurements on 27 patients were analysed. The patient-wise variability of measured temperatures was significantly higher for the ear measurements. Patient-wise linear regressions for the 25 patients with at least three pairs of simultaneous ear and rectal temperature measurements showed large interpatient variability of the association. A linear relationship between the rectal body temperature assessment and the temperature assessment employing the tympanic thermometer is weak. Both measuring methods reflect variance in temperature, but ear measurements showed larger variation. © 2016 Nordic College of Caring Science.

Brown adipose tissue thermogenesis, the basic rest-activity cycle, meal initiation, and bodily homeostasis in rats.

PubMed

Blessing, William; Mohammed, Mazher; Ootsuka, Youichirou

2013-09-10

Laboratory rats alternate between behaviorally active and inactive states every 1-2h throughout the 24hour day, the ultradian basic rest-activity cycle (BRAC). During the behaviorally active phases of the BRAC, brown adipose tissue (BAT) temperature, body and brain temperature, and arterial pressure and heart rate increase in an integrated manner. Since the BAT temperature increases are substantially greater than the corresponding body and brain temperature increases, BAT thermogenesis contributes to the body and brain temperature increases. When food is available ad libitum, eating commences approximately 15min after the onset of an episodic increase in BAT temperature, and not at other times. If no food is available, the rat still disturbs the empty food container approximately 15min after the onset of an episodic increase in BAT temperature, and not at other times. The increase in brain temperature that precedes eating may facilitate the cognitive processing that occurs during the search for food, when the rat engages with the external environment. Rather than being triggered by changes in levels of body fuels or other meal-associated factors, in sedentary laboratory rats with ad libitum access to food, meal initiation normally occurs as part of the centrally-programmed ultradian BRAC. BRAC-associated BAT temperature increases occur in a thermoneutral environment and they are not preceded by falls in body or brain temperature, so they are not homeostatic thermoregulatory responses. The pattern of integrated behaviors and physiological functions associated with the BRAC presumably reflects Darwinian natural selection, and homeostatic thermoregulatory explanations of the BRAC-associated changes in temperature should be considered in this context. Copyright © 2013 Elsevier Inc. All rights reserved.

Pyrolytic graphite gauge for measuring heat flux

NASA Technical Reports Server (NTRS)

Bunker, Robert C. (Inventor); Ewing, Mark E. (Inventor); Shipley, John L. (Inventor)

2002-01-01

A gauge for measuring heat flux, especially heat flux encountered in a high temperature environment, is provided. The gauge includes at least one thermocouple and an anisotropic pyrolytic graphite body that covers at least part of, and optionally encases the thermocouple. Heat flux is incident on the anisotropic pyrolytic graphite body by arranging the gauge so that the gauge surface on which convective and radiative fluxes are incident is perpendicular to the basal planes of the pyrolytic graphite. The conductivity of the pyrolytic graphite permits energy, transferred into the pyrolytic graphite body in the form of heat flux on the incident (or facing) surface, to be quickly distributed through the entire pyrolytic graphite body, resulting in small substantially instantaneous temperature gradients. Temperature changes to the body can thereby be measured by the thermocouple, and reduced to quantify the heat flux incident to the body.

Correlation between Temperature-dependent Fatigue Resistance and Differential Scanning Calorimetry Analysis for 2 Contemporary Rotary Instruments.

PubMed

Arias, Ana; Macorra, José C; Govindjee, Sanjay; Peters, Ove A

2018-04-01

The aim of this study was to assess differences in cyclic fatigue (CF) life of contemporary heat-treated nickel-titanium rotary instruments at room and body temperatures and to document corresponding phase transformations. Forty Hyflex EDM (H-EDM) files (Coltene, Cuyahoga Falls, OH [#25/.08, manufactured by electrical discharge machining]) and 40 TRUShape (TS) files (Dentsply Tulsa Dental Specialties, Tulsa, OK [#25/.06v, manufactured by grinding and shape setting]) were divided into 2 groups (n = 20) for CF resistance tests in a water bath either at room (22°C ± 0.5°C) or body temperature (37°C ± 0.5°C). Instruments were rotated in a simulated canal (angle = 60°, radius = 3 mm, and center of the curvature 5 mm from the tip) until fracture occurred. The motor was controlled by an electric circuit that was interrupted after instrument fracture. The mean half-life and beta and eta Weibull parameters were determined and compared. Two instruments of each brand were subjected to differential scanning calorimetry (DSC). While TS instruments lasted significantly longer at room temperature (mean life = 234.7 seconds; 95% confidence interval [CI], 209-263.6) than at body temperature (mean life = 83.2 seconds; 95% CI, 76-91.1), temperature did not affect H-EDM behavior (room temperature mean life = 725.4 seconds; 95% CI, 658.8-798.8 and body temperature mean life = 717.9 seconds; 95% CI, 636.8-809.3). H-EDM instruments significantly outlasted TS instruments at both temperatures. At body temperature, TS was predominantly austenitic, whereas H-EDM was martensitic or in R-phase. TS was in a mixed austenitic/martensitic phase at 22°C, whereas H-EDM was in the same state as at 37°C. H-EDM had a longer fatigue life than TS, which showed a marked decrease in fatigue life at body temperature; neither the life span nor the state of the microstructure in the DSC differed for H-EDM between room or body temperature. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

The temperature of unheated bodies in a high-speed gas stream

NASA Technical Reports Server (NTRS)

Eckert, E; Weise, W

1941-01-01

The present report deals with temperature measurements on cylinders of 0.2 to 3 millimeters diameter in longitudinal and transverse air flow at speeds of 100 to 300 meters per second. Within the explored test range, that is, the probable laminar boundary layer region, the temperature of the cylinders in axial flow is practically independent of the speed and in good agreement with Pohlhausen's theoretical values; Whereas, in transverse flow, cylinders of certain diameter manifest a close relationship with speed, the ratio of the temperature above the air of the body to the adiabatic stagnation temperature decreases with rising speed and then rises again from a Mach number of 0.6. The importance of this "specific temperature" of the body for heat-transfer studies at high speed is discussed.

Alcohol Poisoning

MedlinePlus

... tinged skin or pale skin Low body temperature (hypothermia) Passing out (unconsciousness) and can't be awakened ... level may drop low enough to cause seizures. Hypothermia. Your body temperature may drop so low that ...

The relationship between virtual body ownership and temperature sensitivity

PubMed Central

Llobera, Joan; Sanchez-Vives, M. V.; Slater, Mel

2013-01-01

In the rubber hand illusion, tactile stimulation seen on a rubber hand, that is synchronous with tactile stimulation felt on the hidden real hand, can lead to an illusion of ownership over the rubber hand. This illusion has been shown to produce a temperature decrease in the hidden hand, suggesting that such illusory ownership produces disownership of the real hand. Here, we apply immersive virtual reality (VR) to experimentally investigate this with respect to sensitivity to temperature change. Forty participants experienced immersion in a VR with a virtual body (VB) seen from a first-person perspective. For half the participants, the VB was consistent in posture and movement with their own body, and in the other half, there was inconsistency. Temperature sensitivity on the palm of the hand was measured before and during the virtual experience. The results show that temperature sensitivity decreased in the consistent compared with the inconsistent condition. Moreover, the change in sensitivity was significantly correlated with the subjective illusion of virtual arm ownership but modulated by the illusion of ownership over the full VB. This suggests that a full body ownership illusion results in a unification of the virtual and real bodies into one overall entity—with proprioception and tactile sensations on the real body integrated with the visual presence of the VB. The results are interpreted in the framework of a ‘body matrix’ recently introduced into the literature. PMID:23720537

Dynamic size responses to climate change: prevailing effects of rising temperature drive long-term body size increases in a semi-arid passerine.

PubMed

Gardner, Janet L; Amano, Tatsuya; Mackey, Brendan G; Sutherland, William J; Clayton, Mark; Peters, Anne

2014-07-01

Changes in animal body size have been widely reported as a correlate of contemporary climate change. Body size affects metabolism and fitness, so changing size has implications for resilience, yet the climatic factors that drive size variation remain poorly understood. We test the role of mean and extreme temperature, rainfall, and remotely sensed primary productivity (NDVI) as drivers of body size in a sedentary, semi-arid Australian passerine, Ptilotula (Lichenostomus)penicillatus, over 23 years. To distinguish effects due to differential growth from changes in population composition, we analysed first-year birds and adults separately and considered climatic variation at three temporal scales (current, previous, and preceding 5 years). The strongest effects related to temperature: in both age classes, larger size was associated with warmer mean temperatures in the previous year, contrary to Bergmann's Rule. Moreover, adults were larger in warmer breeding seasons, while first years was larger after heat waves; these effects are more likely to be mediated through size-dependent mortality, highlighting the role of body size in determining vulnerability to extinction. In addition to temperature, larger adult size was associated with lower primary productivity, which may reflect a trade-off between vegetative growth and nectar production, on which adults rely. Finally, lower rainfall was associated with decreasing size in first year and adults, most likely related to decreased food availability. Overall,body size increased over 23 years, strongly in first-year birds (2.7%) compared with adults (1%), with size outcomes a balance between competing drivers. As rainfall declined over time and productivity remained fairly stable, the temporal increase in body size appears largely driven by rising mean temperature and temperature extremes. Body size responses to environmental change are thus complex and dynamic, driven by effects on growth as well as mortality.

Association between summer temperature and body weight in Japanese adolescents and children: An ecological analysis.

PubMed

Yokoya, Masana; Higuchi, Yukito

2016-11-01

Several experimental studies reported evidence of a negative energy balance at higher temperatures. However, corresponding weight loss has not been noted in clinical practice. This study investigated the geographical association between outdoor temperature and body weight in Japanese adolescents and children. An ecological analysis was conducted using prefecture-level data on the mean body weight of Japanese adolescents and children over a 25-year period and Japanese mesh (regional) climatic data on the mean annual temperature, mean daily maximum temperature in August, and mean daily minimum temperature in January were also analyzed. Correlation analysis uncovered a stronger association between weight and the mean daily maximum temperature in August than with other climatic variables. Moreover, multiple regression analysis indicated that height and the mean daily maximum temperature in August were statistically significant predictors of weight. This suggests that geographical differences in weight in Japanese adolescents and children can be explained by the complementary relationship between height-associated weight gain and weight loss caused by summer heat. Summer temperatures may reduce the proportion of children who are overweight and contribute to geographical differences in body weight in Japanese adolescents and children. Am. J. Hum. Biol. 28:789-795, 2016. © 2016Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

What do foraging wasps optimize in a variable environment, energy investment or body temperature?

PubMed

Kovac, Helmut; Stabentheiner, Anton; Brodschneider, Robert

2015-11-01

Vespine wasps (Vespula sp.) are endowed with a pronounced ability of endothermic heat production. To show how they balance energetics and thermoregulation under variable environmental conditions, we measured the body temperature and respiration of sucrose foragers (1.5 M, unlimited flow) under variable ambient temperature (T a = 20-35 °C) and solar radiation (20-570 W m(-2)). Results revealed a graduated balancing of metabolic efforts with thermoregulatory needs. The thoracic temperature in the shade depended on ambient temperature, increasing from ~37 to 39 °C. However, wasps used solar heat gain to regulate their thorax temperature at a rather high level at low T a (mean T thorax ~ 39 °C). Only at high T a they used solar heat to reduce their metabolic rate remarkably. A high body temperature accelerated the suction speed and shortened foraging time. As the costs of foraging strongly depended on duration, the efficiency could be significantly increased with a high body temperature. Heat gain from solar radiation enabled the wasps to enhance foraging efficiency at high ambient temperature (T a = 30 °C) by up to 63 %. The well-balanced change of economic strategies in response to environmental conditions minimized costs of foraging and optimized energetic efficiency.

Respiratory cooling and thermoregulatory coupling in reptiles.

PubMed

Tattersall, Glenn J; Cadena, Viviana; Skinner, Matthew C

2006-11-01

Comparative physiological research on reptiles has focused primarily on the understanding of mechanisms of the control of breathing as they relate to respiratory gases or temperature itself. Comparatively less research has been done on the possible link between breathing and thermoregulation. Reptiles possess remarkable thermoregulatory capabilities, making use of behavioural and physiological mechanisms to regulate body temperature. The presence of thermal panting and gaping in numerous reptiles, coupled with the existence of head-body temperature differences, suggests that head temperature may be the primary regulated variable rather than body temperature. This review examines the preponderance of head and body temperature differences in reptiles, the occurrence of breathing patterns that possess putative thermoregulatory roles, and the propensity for head and brain temperature to be controlled by reptiles, particularly at higher temperatures. The available evidence suggests that these thermoregulatory breathing patterns are indeed present, though primarily in arid-dwelling reptiles. More importantly, however, it appears that the respiratory mechanisms that have the capacity to cool evolved initially in reptiles, perhaps as regulatory mechanisms for preventing overheating of the brain. Examining the control of these breathing patterns and their efficacy at regulating head or brain temperature may shed light on the evolution of thermoregulatory mechanisms in other vertebrates, namely the endothermic mammals and birds.

Radiant heat affects thermoregulation and energy expenditure during rewarming from torpor.

PubMed

Geiser, F; Drury, R L

2003-02-01

The high expenditure of energy required for endogenous rewarming is one of the widely perceived disadvantages of torpor. However, recent evidence demonstrates that passive rewarming either by the increase of ambient temperature or by basking in the sun appears to be common in heterothermic birds and mammals. As it is presently unknown how radiant heat affects energy expenditure during rewarming from torpor and little is known about how it affects normothermic thermoregulation, we quantified the effects of radiant heat on body temperature and metabolic rate of the small (body mass 25 g) marsupial Sminthopsis macroura in the laboratory. Normothermic resting individuals exposed to radiant heat were able to maintain metabolic rates near basal levels (at 0.91 ml O(2) g(-1) h(-1)) and a constant body temperature down to an ambient temperature of 12 degrees C. In contrast, metabolic rates of individuals without access to radiant heat were 4.5-times higher at an ambient temperature of 12 degrees C and body temperature fell with ambient temperature. During radiant heat-assisted passive rewarming from torpor, animals did not employ shivering but appeared to maximise uptake of radiant heat. Their metabolic rate increased only 3.2-times with a 15- degrees C rise of body temperature (Q(10)=2.2), as predicted by Q(10) effects. In contrast, during active rewarming shivering was intensive and metabolic rates showed an 11.6-times increase. Although body temperature showed a similar absolute change between the beginning and the end of the rewarming process, the overall energetic cost during active rewarming was 6.3-times greater than that during passive, radiant heat-assisted rewarming. Our study demonstrates that energetic models assuming active rewarming from torpor at low ambient temperatures can substantially over-estimate energetic costs. The low energy expenditure during passive arousal provides an alternative explanation as to why daily torpor is common in sunny regions and suggests that the prevalence of torpor in low latitudes may have been under-estimated in the past.

Non-linear scaling of oxygen consumption and heart rate in a very large cockroach species (Gromphadorhina portentosa): correlated changes with body size and temperature.

PubMed

Streicher, Jeffrey W; Cox, Christian L; Birchard, Geoffrey F

2012-04-01

Although well documented in vertebrates, correlated changes between metabolic rate and cardiovascular function of insects have rarely been described. Using the very large cockroach species Gromphadorhina portentosa, we examined oxygen consumption and heart rate across a range of body sizes and temperatures. Metabolic rate scaled positively and heart rate negatively with body size, but neither scaled linearly. The response of these two variables to temperature was similar. This correlated response to endogenous (body mass) and exogenous (temperature) variables is likely explained by a mutual dependence on similar metabolic substrate use and/or coupled regulatory pathways. The intraspecific scaling for oxygen consumption rate showed an apparent plateauing at body masses greater than about 3 g. An examination of cuticle mass across all instars revealed isometric scaling with no evidence of an ontogenetic shift towards proportionally larger cuticles. Published oxygen consumption rates of other Blattodea species were also examined and, as in our intraspecific examination of G. portentosa, the scaling relationship was found to be non-linear with a decreasing slope at larger body masses. The decreasing slope at very large body masses in both intraspecific and interspecific comparisons may have important implications for future investigations of the relationship between oxygen transport and maximum body size in insects.

Oligonol supplementation attenuates body temperature and the circulating levels of prostaglandin E2 and cyclooxygenase-2 after heat stress in humans.

PubMed

Shin, Young Oh; Lee, Jeong Beom; Song, Young Ju; Min, Young Ki; Yang, Hun Mo

2013-04-01

Oligonol, a phenolic production from lychee, has been reported to exhibit anti-oxidative and anti-inflammatory effects. This study investigated the effect of Oligonol supplementation on circulating levels of prostaglandin E2 (PGE2) and cyclooxygenase (COX)-2, as well as body temperature, after heat stress in 17 healthy human male volunteers (age, 21.6±2.1 years). All experiments were performed in an automated climate chamber (26.0°C±0.5°C, relative humidity 60%±3.0%, air velocity less than 1 m/sec) between 2 and 5 p.m. Subjects ingested an Oligonol (100 mg)-containing beverage or placebo beverage before half-body immersion into hot water (42°C±0.5°C for 30 min). Tympanic and skin temperatures were measured and mean body temperatures were calculated. Serum concentrations of PGE2 and COX-2 were analyzed before, immediately after, and 60 min after immersion. Oligonol intake significantly prevented elevation of tympanic (temperature difference: 0.17°C at Post, P<.05; 0.17°C at Re-60, P<.05) and mean body temperatures (temperature difference: 0.18°C at Post, P<.05; 0.15°C at Re-60, P<.05), and lowered concentrations of serum PGE2 (increased by 13.3% vs. 29.6% at Post, P<.05) and COX-2 (increased by 15.6% vs. 21.8% at Post, P<.05), compared to placebo beverage. Our result suggests that Oligonol has the potential to suppress increases in body temperature under heat stress, and this is associated with decreases in serum levels of PGE2 and COX-2.

The Effect of Different Oceanic Abiotic Factors on Prokaryotic Body Sizes

NASA Astrophysics Data System (ADS)

Pidathala, S.; Bellon, M.; Heim, N.; Payne, J.

2016-12-01

We are studying the impact of abiotic factors in the Pacific and Atlantic on prokaryotic body sizes and genome sizes because we are interested in the manner in which abiotic factors influence genome sizes independent of their influence on body sizes. Some research has been done in the past on marine bacterial evolution, including data collection on marine ecology in relation to bacterial body sizes (Straza 2009). We are using the abiotic factors: temperature, salinity, and pH to compare the biovolumes/genome sizes of different phyla by using R. We made 9 scatter plots to model these relationships. Regardless of the phyla or the ocean, we found that there is no relation between pH, temperature, and body size, with several exceptions: Deinococcus. thermus has an indirect relationship with size in respect to temperature; size only correlates to temperature for phyla that are thermophiles. We also found that bacteria like D. thermus and Thermotogae are taxa only found in higher temperatures. Additionally, almost all phyla have genome sizes restricted by certain pH levels:, Proteobacteria only reach genomes with acidity levels greater than 6. In terms of salinity levels, certain bacteria are only found within a small range, and others, like Proteobacteria, can only reach genomes at low salinity levels. Finally, Proteobacteria have large genome sizes between 30 and 40 °, and Crenarchaeota have constant genome sizes in higher temperatures. Conclusively, we discovered that these abiotic factors generally do not affect body size, with the exception of D. thermus' indirect relationship to temperature due to its small biovolume in high temperatures. However, we determined that these abiotic factors have a great impact on genome sizes. This is due to genome size independence from body size. Also, genome size could have served as an adaptive feature for bacteria in marine environments, explaining why different phyla may have diverged to accommodate their lifestyles.

Effects of ingested crude and dispersed crude oil on thermoregulation in ducks (Anas platyrhynchos)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jenssen, B.M.

1989-02-01

Thermoregulatory effects of ingested doses of Statfjord A crude oil and of this oil mixed with the dispersant Finasol OSR-5 were studied in adult domestic ducks (Anas platyrhynchos) exposed to ambient temperatures of +16 degrees C and -17 degrees C. The data show that ingestion of both the crude and the oil-dispersant mixture resulted in an increased body temperature during exposure to the low ambient temperature (-17 degrees C). Neither contaminant had any effect on body temperature during exposure to +16 degrees C. Ingestion of the contaminants had no effect on metabolic heat production at either ambient temperature. The breastmore » skin temperature of the ducks in both contaminated groups was significantly decreased when the ducks were exposed to the low ambient temperature. This indicates that the increase in body temperature observed in the contaminated ducks at the low ambient temperature is due to an increase in peripheral vasoconstriction.« less

Low-cost compact thermal imaging sensors for body temperature measurement

NASA Astrophysics Data System (ADS)

Han, Myung-Soo; Han, Seok Man; Kim, Hyo Jin; Shin, Jae Chul; Ahn, Mi Sook; Kim, Hyung Won; Han, Yong Hee

2013-06-01

This paper presents a 32x32 microbolometer thermal imaging sensor for human body temperature measurement. Waferlevel vacuum packaging technology allows us to get a low cost and compact imaging sensor chip. The microbolometer uses V-W-O film as sensing material and ROIC has been designed 0.35-um CMOS process in UMC. A thermal image of a human face and a hand using f/1 lens convinces that it has a potential of human body temperature for commercial use.

The effects of measurement site and ambient temperature on body temperature values in healthy older adults: a cross-sectional comparative study.

PubMed

Lu, Shu-Hua; Dai, Yu-Tzu; Yen, Chung-Jen

2009-11-01

Accurate baseline body temperature measurement is essential for assessment. Tympanic membrane temperature (TMT) measurement is popular, but there is no consensus on whether it is as accurate as oral temperature (OT) for use with the elderly at varying ambient temperature levels. To test agreement between TMT and OT measurement of body temperature among an elderly population; and to explore whether agreement between the two sites depends on ambient temperature. A cross-sectional comparison study. Two samples of older community-dwelling adults were recruited from 17 community senior citizen centers in Taipei, Taiwan in winter (n=262) and summer (n=257) of 2007. TMT and OT were simultaneously measured by electronic infrared ear thermometer and electronic digital thermometer. Ambient temperatures measured by digital thermo-hygrometer of the data collection setting were recorded when body temperature was taken. In winter mean TMT was 36.64 degrees C (S.D. 0.37), and mean OT was 36.74 degrees C (S.D. 0.18). In summer, the mean TMT was 37.05 degrees C (S.D. 0.30) and mean OT was 36.85 degrees C (S.D. 0.22). The relationship between TMT and OT were r=0.42 (p<0.001) in winter and r=0.57 (p<0.001) in summer. The values of OT were used as standard to assess the accuracy of the measurement. The bias between TMT and OT was -0.10 degrees C (S.D. 0.34) and 95% limits of agreement were 0.57 and -0.77 degrees C in winter; and bias was 0.20 degrees C (S.D. 0.25) and 95% limits of agreement were 0.69 and -0.29 degrees C in summer. The findings of this study demonstrate that the TMT has high variability that may under or over estimate body temperatures. There is a lack of agreement in body temperatures values between TMT and OT in community-dwelling elderly in both winter and summer. OT was more stable than TMT regardless of ambient temperature influences. Therefore, the oral cavity is preferable to the TM site for temperature measurement in alert elderly. The limitation of this study is that hospitalized patients who are most likely to need temperature measurement are not included in this study.

Oral administration of D-aspartate, but not L-aspartate, depresses rectal temperature and alters plasma metabolites in chicks.

PubMed

Erwan, Edi; Chowdhury, Vishwajit Sur; Nagasawa, Mao; Goda, Ryosei; Otsuka, Tsuyoshi; Yasuo, Shinobu; Furuse, Mitsuhiro

2014-07-25

L-Aspartate (L-Asp) and D-aspartate (D-Asp) are physiologically important amino acids in mammals and birds. However, the functions of these amino acids have not yet been fully understood. In this study, we therefore examined the effects of L-Asp and D-Asp in terms of regulating body temperature, plasma metabolites and catecholamines in chicks. Chicks were first orally administered with different doses (0, 3.75, 7.5 and 15 mmol/kg body weight) of L- or D-Asp to monitor the effects of these amino acids on rectal temperature during 120 min of the experimental period. Oral administration of D-Asp, but not of L-Asp, linearly decreased the rectal temperature in chicks. Importantly, orally administered D-Asp led to a significant reduction in body temperature in chicks even under high ambient temperature (HT) conditions. However, centrally administered D-Asp did not significantly influence the body temperature in chicks. As for plasma metabolites and catecholamines, orally administered D-Asp led to decreased triacylglycerol and uric acid concentrations and increased glucose and chlorine concentrations but did not alter plasma catecholamines. These results suggest that oral administration of D-Asp may play a potent role in reducing body temperature under both normal and HT conditions. The alteration of plasma metabolites further indicates that D-Asp may contribute to the regulation of metabolic activity in chicks. Copyright © 2014 Elsevier Inc. All rights reserved.

Faecal glucocorticoid metabolites and body temperature in Australian merino ewes (Ovis aries) during summer artificial insemination (AI) program

PubMed Central

Sawyer, Gregory; Parisella, Simone

2018-01-01

Reproductive wastage is a key issue for sheep producers, both regionally and globally. The reproductive output of farm animals can be influenced by physiological and environmental factors. Rapid and reliable quantification of physiological stress can provide a useful tool for designing and testing on-farm management interventions to improve farm animal welfare and productivity. In this study, we quantified physiological stress non-invasively using faecal glucocorticoid metabolites-FGMs analysis and body temperature measurements of 15 superovulated donor merino ewes (Ovis aries) during participation in artificial insemination (AI) program conducted during 2015/2016 Australian summer. We hypothesized that low percentage transferable embryos in donor merino ewes will be associated positively with higher body temperature and/or higher FGMs in these ewes. Temperature humidity index (THI) was calculated and found within high thermal stress range during the two AI trials. Overall, results showed none of the factors (ewe ID, AI trial no., THI or FGMs) were significant for reduced percentage transferrable embryos, except ewe body temperature was highly significant (p = 0.014). Within AI trial comparisons showed significant positive associations between higher FGMs and body temperature with reduced transferrable embryos. These results suggest that Australian merino ewes participating in summer AI trials can experience physiological stress. Prolonged activation of the stress endocrine response and high body temperature (e.g. ensued from heat stress) could impact on ewe reproductive output. Therefore, future research should apply minimally invasive physiological tools to gather baseline information on physiological stress in merino sheep to enable the development of new farm-friendly methods of managing stress. PMID:29381759

Faecal glucocorticoid metabolites and body temperature in Australian merino ewes (Ovis aries) during summer artificial insemination (AI) program.

PubMed

Narayan, Edward; Sawyer, Gregory; Parisella, Simone

2018-01-01

Reproductive wastage is a key issue for sheep producers, both regionally and globally. The reproductive output of farm animals can be influenced by physiological and environmental factors. Rapid and reliable quantification of physiological stress can provide a useful tool for designing and testing on-farm management interventions to improve farm animal welfare and productivity. In this study, we quantified physiological stress non-invasively using faecal glucocorticoid metabolites-FGMs analysis and body temperature measurements of 15 superovulated donor merino ewes (Ovis aries) during participation in artificial insemination (AI) program conducted during 2015/2016 Australian summer. We hypothesized that low percentage transferable embryos in donor merino ewes will be associated positively with higher body temperature and/or higher FGMs in these ewes. Temperature humidity index (THI) was calculated and found within high thermal stress range during the two AI trials. Overall, results showed none of the factors (ewe ID, AI trial no., THI or FGMs) were significant for reduced percentage transferrable embryos, except ewe body temperature was highly significant (p = 0.014). Within AI trial comparisons showed significant positive associations between higher FGMs and body temperature with reduced transferrable embryos. These results suggest that Australian merino ewes participating in summer AI trials can experience physiological stress. Prolonged activation of the stress endocrine response and high body temperature (e.g. ensued from heat stress) could impact on ewe reproductive output. Therefore, future research should apply minimally invasive physiological tools to gather baseline information on physiological stress in merino sheep to enable the development of new farm-friendly methods of managing stress.

Brain Basics: Understanding Sleep

MedlinePlus

... slow, and muscles relax even further. Your body temperature drops and eye movements stop. Brain wave activity ... functions from daily fluctuations in wakefulness to body temperature, metabolism, and the release of hormones. They control ...

Commonly Abused Drugs Charts

MedlinePlus

... term Narrowed blood vessels; enlarged pupils; increased body temperature, heart rate, and blood pressure; headache; abdominal pain ... unconsciousness, slowed heart rate and breathing, lower body temperature, seizures, coma, death. Long-term Unknown. Other Health- ...

The Impact of Temperature and Body Size on Fundamental Flight Tone Variation in the Mosquito Vector Aedes aegypti (Diptera: Culicidae): Implications for Acoustic Lures.

PubMed

Villarreal, Susan M; Winokur, Olivia; Harrington, Laura

2017-09-01

Aedes aegypti (L.) males use female flight tone as a means of mate localization. By playing the sound of a flying female, males can be attracted to a trap to monitor mosquito populations and the progress of transgenic male releases. However, the female flight tone used to attract males needs to be optimized to maximize trap effectiveness. The fundamental frequency of female flight tone could be influenced by both body size and ambient temperature. However, no analysis yet has considered both the effect of body size and temperature on female flight tone of Ae. aegypti. Here, we present results for both these factors by recording the sounds of free-flying and tethered females across multiple temperature environments and with females reared for small, medium, and large body sizes. We demonstrate that female fundamental frequency is highly dependent on the environmental temperature, increasing ∼8-13 Hz with each °C gain. Body size and whether a female was tethered or free-flying did not impact the relationship between frequency and temperature, although further analysis is warranted. Our study highlights the importance of understanding the relationship between flight tone and temperature, and will inform the design of male mosquito traps. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America.

Using body temperature, food and water consumption as biomarkers of disease progression in mice with Eμ-myc lymphoma

PubMed Central

Hunter, J E; Butterworth, J; Perkins, N D; Bateson, M; Richardson, C A

2014-01-01

Background: Non-invasive biomarkers of disease progression in mice with cancer are lacking making it challenging to implement appropriate humane end points. We investigated whether body temperature, food and water consumption could be used to predict tumour burden. Methods: Thirty-six male, wild-type C57Bl/6 mice were implanted with subcutaneous RFID temperature sensors and inoculated with Eμ-myc tumours that infiltrate lymphoid tissue. Results: Decrease in body temperature over the course of the study positively predicted post-mortem lymph node tumour burden (R2=0.68, F(1,22)=44.8, P<0.001). At experimental and humane end points, all mice that had a mean decrease in body temperature of 0.7 °C or greater had lymph nodes heavier than 0.5 g (100% sensitivity), whereas a mean decrease in body temperature <0.7 °C always predicted lymph nodes lighter than 0.5 g (100% specificity). The mean decrease in food consumption in each cage also predicted mean post-mortem lymph node tumour burden at 3 weeks (R2=0.89, F(1,3)=23.2, P=0.017). Conclusion: Temperature, food and water consumption were useful biomarkers of disease progression in mice with lymphoma and could potentially be used more widely to monitor mice with other forms of cancer. PMID:24407190

Metabolic heat production and thermal conductance are mass-independent adaptations to thermal environment in birds and mammals.

PubMed

Fristoe, Trevor S; Burger, Joseph R; Balk, Meghan A; Khaliq, Imran; Hof, Christian; Brown, James H

2015-12-29

The extent to which different kinds of organisms have adapted to environmental temperature regimes is central to understanding how they respond to climate change. The Scholander-Irving (S-I) model of heat transfer lays the foundation for explaining how endothermic birds and mammals maintain their high, relatively constant body temperatures in the face of wide variation in environmental temperature. The S-I model shows how body temperature is regulated by balancing the rates of heat production and heat loss. Both rates scale with body size, suggesting that larger animals should be better adapted to cold environments than smaller animals, and vice versa. However, the global distributions of ∼9,000 species of terrestrial birds and mammals show that the entire range of body sizes occurs in nearly all climatic regimes. Using physiological and environmental temperature data for 211 bird and 178 mammal species, we test for mass-independent adaptive changes in two key parameters of the S-I model: basal metabolic rate (BMR) and thermal conductance. We derive an axis of thermal adaptation that is independent of body size, extends the S-I model, and highlights interactions among physiological and morphological traits that allow endotherms to persist in a wide range of temperatures. Our macrophysiological and macroecological analyses support our predictions that shifts in BMR and thermal conductance confer important adaptations to environmental temperature in both birds and mammals.

Temperature Monitoring and Perioperative Thermoregulation

PubMed Central

Sessler, Daniel I.

2008-01-01

Most clinically available thermometers accurately report the temperature of whatever tissue is being measured. The difficulty is that no reliably core-temperature measuring sites are completely non-invasive and easy to use — especially in patients not having general anesthesia. Nonetheless, temperature can be reliably measured in most patients. Body temperature should be measured in patients having general anesthesia exceeding 30 minutes in duration, and in patients having major operations under neuraxial anesthesia. Core body temperature is normally tightly regulated. All general anesthetics produce a profound dose-dependent reduction in the core temperature triggering cold defenses including arterio-venous shunt vasoconstriction and shivering. Anesthetic-induced impairment of normal thermoregulatory control, and the resulting core-to-peripheral redistribution of body heat, is the primary cause of hypothermia in most patients. Neuraxial anesthesia also impairs thermoregulatory control, although to a lesser extant than general anesthesia. Prolonged epidural analgesia is associated with hyperthermia whose cause remains unknown. PMID:18648241

Effect of low air velocities on thermal homeostasis and comfort during exercise at space station operational temperature and humidity

NASA Technical Reports Server (NTRS)

Beumer, Ronald J.

1989-01-01

The effectiveness of different low air velocities in maintaining thermal comfort and homeostasis during exercise at space station operational temperature and humidity was investigated. Five male subjects exercised on a treadmill for successive ten minute periods at 60, 71, and 83 percent of maximum oxygen consumption at each of four air velocities, 30, 50, 80, and 120 ft/min, at 22 C and 62 percent relative humidity. No consistent trends or statistically significant differences between air velocities were found in body weight loss, sweat accumulation, or changes in rectal, skin, and body temperatures. Occurrence of the smallest body weight loss at 120 ft/min, the largest sweat accumulation at 30 ft/min, and the smallest rise in rectal temperature and the greatest drop in skin temperature at 120 ft/min all suggested more efficient evaporative cooling at the highest velocity. Heat storage at all velocities was evidenced by increased rectal and body temperatures; skin temperatures declined or increased only slightly. Body and rectal temperature increases corresponded with increased perception of warmth and slight thermal discomfort as exercise progressed. At all air velocities, mean thermal perception never exceeded warm and mean discomfort, greatest at 30 ft/min, was categorized at worst as uncomfortable; sensation of thermal neutrality and comfort returned rapidly after cessation of exercise. Suggestions for further elucidation of the effects of low air velocities on thermal comfort and homeostasis include larger numbers of subjects, more extensive skin temperature measurements and more rigorous analysis of the data from this study.

Coping with thermal challenges: physiological adaptations to environmental temperatures.

PubMed

Tattersall, Glenn J; Sinclair, Brent J; Withers, Philip C; Fields, Peter A; Seebacher, Frank; Cooper, Christine E; Maloney, Shane K

2012-07-01

Temperature profoundly influences physiological responses in animals, primarily due to the effects on biochemical reaction rates. Since physiological responses are often exemplified by their rate dependency (e.g., rate of blood flow, rate of metabolism, rate of heat production, and rate of ion pumping), the study of temperature adaptations has a long history in comparative and evolutionary physiology. Animals may either defend a fairly constant temperature by recruiting biochemical mechanisms of heat production and utilizing physiological responses geared toward modifying heat loss and heat gain from the environment, or utilize biochemical modifications to allow for physiological adjustments to temperature. Biochemical adaptations to temperature involve alterations in protein structure that compromise the effects of increased temperatures on improving catalytic enzyme function with the detrimental influences of higher temperature on protein stability. Temperature has acted to shape the responses of animal proteins in manners that generally preserve turnover rates at animals' normal, or optimal, body temperatures. Physiological responses to cold and warmth differ depending on whether animals maintain elevated body temperatures (endothermic) or exhibit minimal internal heat production (ectothermic). In both cases, however, these mechanisms involve regulated neural and hormonal over heat flow to the body or heat flow within the body. Examples of biochemical responses to temperature in endotherms involve metabolic uncoupling mechanisms that decrease metabolic efficiency with the outcome of producing heat, whereas ectothermic adaptations to temperature are best exemplified by the numerous mechanisms that allow for the tolerance or avoidance of ice crystal formation at temperatures below 0°C. 2012 American Physiological Society. Compr Physiol 2:2037-2061, 2012.

A comparison of hydration effect on body fluid and temperature regulation between Malaysian and Japanese males exercising at mild dehydration in humid heat

PubMed Central

2014-01-01

Background This study investigated the effect of hydration differences on body fluid and temperature regulation between tropical and temperate indigenes exercising in the heat. Methods Ten Japanese and ten Malaysian males with matched physical characteristics (height, body weight, and peak oxygen consumption) participated in this study. Participants performed exercise for 60 min at 55% peak oxygen uptake followed by a 30-min recovery at 32°C and 70% relative air humidity with hydration (4 times each, 3 mL per kg body weight, 37°C) or without hydration. Rectal temperature, skin temperature, heart rate, skin blood flow, and blood pressure were measured continuously. The percentage of body weight loss and total sweat loss were calculated from body weight measurements. The percentage change in plasma volume was estimated from hemoglobin concentration and hematocrit. Results Malaysian participants had a significantly lower rectal temperature, a smaller reduction in plasma volume, and a lower heart rate in the hydrated condition than in the non-hydrated condition at the end of exercise (P <0.05), whereas Japanese participants showed no difference between the two hydration conditions. Hydration induced a greater total sweat loss in both groups (P <0.05), and the percentage of body weight loss in hydrated Malaysians was significantly less than in hydrated Japanese (P <0.05). A significant interaction between groups and hydration conditions was observed for the percentage of mean cutaneous vascular conductance during exercise relative to baseline (P <0.05). Conclusions The smaller reduction in plasma volume and percentage body weight loss in hydrated Malaysians indicated an advantage in body fluid regulation. This may enable Malaysians to reserve more blood for circulation and heat dissipation and thereby maintain lower rectal temperatures in a hydrated condition. PMID:24490869

[Design of a miniaturized blood temperature-varying system based on computer distributed control].

PubMed

Xu, Qiang; Zhou, Zhaoying; Peng, Jiegang; Zhu, Junhua

2007-10-01

Blood temperature-varying has been widely applied in clinical practice such as extracorporeal circulation for whole-body perfusion hyperthermia (WBPH), body rewarming and blood temperature-varying in organ transplantation. This paper reports a novel DCS (Computer distributed control)-based blood temperature-varying system which includes therapy management function and whose hardware and software can be extended easily. Simulation results illustrate that this system provides precise temperature control with good performance in various operation conditions.

Assessment of axillary temperature for the evaluation of normal body temperature of healthy young adults at rest in a thermoneutral environment.

PubMed

Marui, Shuri; Misawa, Ayaka; Tanaka, Yuki; Nagashima, Kei

2017-02-22

The aims of this study were to (1) evaluate whether recently introduced methods of measuring axillary temperature are reliable, (2) examine if individuals know their baseline body temperature based on an actual measurement, and (3) assess the factors affecting axillary temperature and reevaluate the meaning of the axillary temperature. Subjects were healthy young men and women (n = 76 and n = 65, respectively). Three measurements were obtained: (1) axillary temperature using a digital thermometer in a predictive mode requiring 10 s (T ax-10 s ), (2) axillary temperature using a digital thermometer in a standard mode requiring 10 min (T ax-10 min ), and (3) tympanic membrane temperature continuously measured by infrared thermometry (T ty ). The subjects answered questions about eating and exercise habits, sleep and menstrual cycles, and thermoregulation and reported what they believed their regular body temperature to be (T reg ). T reg , T ax-10 s , T ax-10 min , and T ty were 36.2 ± 0.4, 36.4 ± 0.5, 36.5 ± 0.4, and 36.8 ± 0.3 °C (mean ± SD), respectively. There were correlations between T ty and T ax-10 min , T ty and T ax-10 s , and T ax-10 min and T ax-10 s (r = .62, r = .46, and r = .59, respectively, P < .001), but not between T reg and T ax-10 s (r = .11, P = .20). A lower T ax-10 s was associated with smaller body mass indices and irregular menstrual cycles. Modern devices for measuring axillary temperature may have changed the range of body temperature that is recognized as normal. Core body temperature variations estimated by tympanic measurements were smaller than those estimated by axillary measurements. This variation of axillary temperature may be due to changes in the measurement methods introduced by modern devices and techniques. However, axillary temperature values correlated well with those of tympanic measurements, suggesting that the technique may reliably report an individual's state of health. It is important for individuals to know their baseline axillary temperature to evaluate subsequent temperature measurements as normal or abnormal. Moreover, axillary temperature variations may, in part, reflect fat mass and changes due to the menstrual cycle.

Effects of pregnancy on body temperature and locomotor performance of velvet geckos.

PubMed

Dayananda, Buddhi; Ibargüengoytía, Nora; Whiting, Martin J; Webb, Jonathan K

2017-04-01

Pregnancy is a challenging period for egg laying squamates. Carrying eggs can encumber females and decrease their locomotor performance, potentially increasing their risk of predation. Pregnant females can potentially reduce this handicap by selecting higher temperatures to increase their sprint speed and ability to escape from predators, or to speed up embryonic development and reduce the period during which they are burdened with eggs ('selfish mother' hypothesis). Alternatively, females might select more stable body temperatures during pregnancy to enhance offspring fitness ('maternal manipulation hypothesis'), even if the maintenance of such temperatures compromises a female's locomotor performance. We investigated whether pregnancy affects the preferred body temperatures and locomotor performance of female velvet geckos Amalosia lesueurii. We measured running speed of females during late pregnancy, and one week after they laid eggs at four temperatures (20°, 25°, 30° and 35°C). Preferred body temperatures of females were measured in a cost-free thermal gradient during late pregnancy and one week after egg-laying. Females selected higher and more stable set-point temperatures when they were pregnant (mean =29.0°C, T set =27.8-30.5°C) than when they were non-pregnant (mean =26.2°C, T set =23.7-28.7°C). Pregnancy was also associated with impaired performance; females sprinted more slowly at all four test temperatures when burdened with eggs. Although females selected higher body temperatures during late pregnancy, this increase in temperature did not compensate for their impaired running performance. Hence, our results suggest that females select higher temperatures during pregnancy to speed up embryogenesis and reduce the period during which they have reduced performance. This strategy may decrease a female's probability of encountering predatory snakes that use the same microhabitats for thermoregulation. Selection of stable temperatures by pregnant females may also benefit embryos, but manipulative experiments are necessary to test this hypothesis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of Heat Wave on Body Temperature and Blood Pressure in the Poor and Elderly

PubMed Central

Kim, Soyeon; Cheong, Hae-Kwan; Ahn, Byungok; Choi, Kyusik

2012-01-01

Objectives We aimed to investigate the acute effects of heat stress on body temperature and blood pressure of elderly individuals living in poor housing conditions. Methods Repeated measurements of the indoor temperature, relative humidity, body temperature, and blood pressure were conducted for 20 elderly individuals living in low-cost dosshouses in Seoul during hot summer days in 2010. Changes in the body temperature, systolic blood pressure (SBP) and diastolic blood pressure (DBP) according to variations in the indoor and outdoor temperature and humidity were analyzed using a repeated-measures ANOVA controlling for age, sex, alcohol, and smoking. Results Average indoor and outdoor temperatures were 31.47℃ (standard deviation [SD], 0.97℃) and 28.15℃ (SD, 2.03℃), respectively. Body temperature increased by 0.21℃ (95% confidence interval [CI], 0.16 to 0.26℃) and 0.07℃ (95% CI, 0.04 to 0.10℃) with an increase in the indoor and outdoor temperature of 1℃. DBP decreased by 2.05 mmHg (95% CI, 0.05 to 4.05 mmHg), showing a statistical significance, as the indoor temperature increased by 1℃, while it increased by 0.20 mmHg (95% CI, -0.83 to 1.22 mmHg) as outdoor temperature increased by 1℃. SBP decreased by 1.75 mmHg (95% CI, -1.11 to 4.61 mmHg) and 0.35 mmHg (95% CI, -1.04 to 1.73 mmHg), as the indoor and outdoor temperature increased by 1℃, respectively. The effects of relative humidity on SBP and DBP were not statistically significant for both indoor and outdoor. Conclusions The poor and elderly are directly exposed to heat waves, while their vital signs respond sensitively to increase in temperature. Careful adaptation strategies to climate change considering socioeconomic status are therefore necessary. PMID:22888472

Effects of heat wave on body temperature and blood pressure in the poor and elderly.

PubMed

Kim, Young-Min; Kim, Soyeon; Cheong, Hae-Kwan; Ahn, Byungok; Choi, Kyusik

2012-01-01

We aimed to investigate the acute effects of heat stress on body temperature and blood pressure of elderly individuals living in poor housing conditions. Repeated measurements of the indoor temperature, relative humidity, body temperature, and blood pressure were conducted for 20 elderly individuals living in low-cost dosshouses in Seoul during hot summer days in 2010. Changes in the body temperature, systolic blood pressure (SBP) and diastolic blood pressure (DBP) according to variations in the indoor and outdoor temperature and humidity were analyzed using a repeated-measures ANOVA controlling for age, sex, alcohol, and smoking. Average indoor and outdoor temperatures were 31.47℃ (standard deviation [SD], 0.97℃) and 28.15℃ (SD, 2.03℃), respectively. Body temperature increased by 0.21℃ (95% confidence interval [CI], 0.16 to 0.26℃) and 0.07℃ (95% CI, 0.04 to 0.10℃) with an increase in the indoor and outdoor temperature of 1℃. DBP decreased by 2.05 mmHg (95% CI, 0.05 to 4.05 mmHg), showing a statistical significance, as the indoor temperature increased by 1℃, while it increased by 0.20 mmHg (95% CI, -0.83 to 1.22 mmHg) as outdoor temperature increased by 1℃. SBP decreased by 1.75 mmHg (95% CI, -1.11 to 4.61 mmHg) and 0.35 mmHg (95% CI, -1.04 to 1.73 mmHg), as the indoor and outdoor temperature increased by 1℃, respectively. The effects of relative humidity on SBP and DBP were not statistically significant for both indoor and outdoor. The poor and elderly are directly exposed to heat waves, while their vital signs respond sensitively to increase in temperature. Careful adaptation strategies to climate change considering socioeconomic status are therefore necessary.

Genetics Home Reference: familial dysautonomia

MedlinePlus

... and the regulation of blood pressure and body temperature. It also affects the sensory nervous system, which ... tears, frequent lung infections, and difficulty maintaining body temperature. Older infants and young children with familial dysautonomia ...

The role of depressed metabolism in increased radio-resistance

NASA Technical Reports Server (NTRS)

Musacchia, X. J.

1975-01-01

The results of experiments on hamsters and rats to determine physiological responses to various temperature conditions are presented. The experimental methods described are considered to be applicable to future mammalian experiments in space. Renal function was examined in the golden hamster as a function of body temperature. Hamsters were also acclimated to heat and metabolic rates, body temperature, skin temperature, cardiac distribution and whole body hematocrits were measured. In addition, the effects of heat stress on the intestinal transport of sugars in the hamster and rat were studied. The biological effects of prolonged space flight and methods of simulating weightlessness are also discussed.

Thermal properties of nuclear matter in a variational framework with relativistic corrections

NASA Astrophysics Data System (ADS)

Zaryouni, S.; Hassani, M.; Moshfegh, H. R.

2014-01-01

The properties of hot symmetric nuclear matter for a wide range of densities and temperatures are investigated by employing the AV14 potential within the lowest order constrained variational (LOCV) method with the inclusion of a phenomenological three-body force as well as relativistic corrections. The relativistic corrections of many-body kinetic energies as well as the boot interaction corrections are presented for a wide range of densities and temperatures. The free energy, pressure, incompressibility, and other thermodynamic quantities of symmetric nuclear matter are obtained and discussed. The critical temperature is found, and the liquid-gas phase transition is analyzed both with and without the inclusion of three-body forces and relativistic corrections in the LOCV approach. It is shown that the critical temperature is strongly affected by the three-body forces but does not depend on the relativistic corrections. Finally, the results obtained in the present study are compared with other many-body calculations and experimental predictions.

Thermoregulation of a temperate reptile in a forested habitat.

PubMed

Corkery, Ilse; Bell, Ben D; Nelson, Nicola J

2018-04-01

A major focus in zoology is to understand the phenotypic responses of animals to environmental variation. This is particularly important when dealing with ectotherms in a thermally heterogenous environment. We measured body temperatures of a free-ranging, medium sized temperate reptile, the tuatara, Sphenodon punctatus, to investigate its thermal opportunities and the degree to which the animal actively regulates its body temperature. We found high variation in body temperature between individuals, but this variation could not be attributed to sex or body size. However, variation among individuals in timing of burrow use did affect body temperature and in one of the years studied tuatara were found to be more effective in their thermoregulation when sharing a burrow with a seabird (Pachyptila turtur). The strength of this study is that it includes both biotic and behavioural components of the thermal environment of a temperate reptile, areas which are often missing from thermal studies that focus on the abiotic aspects. Copyright © 2018 Elsevier GmbH. All rights reserved.

Closed cell metal foam method

DOEpatents

Patten, James W.

1978-01-01

Foamed metals and metal alloys which have a closed cellular structure are prepared by heating a metal body containing entrapped inert gas uniformly distributed throughout to a temperature above the melting point of the metal and maintaining the body at this temperature a period of time sufficient to permit the entrapped gas to expand, forming individual cells within the molten metal, thus expanding and foaming the molten metal. After cell formation has reached the desired amount, the foamed molten metal body is cooled to below the melting temperature of the metal. The void area or density of the foamed metal is controlled by predetermining the amount of inert gas entrapped in the metal body and by the period of time the metal body is maintained in the molten state. This method is useful for preparing foamed metals and metal alloys from any metal or other material of which a body containing entrapped inert gas can be prepared.

Effect of brachycephaly and body condition score on respiratory thermoregulation of healthy dogs.

PubMed

Davis, Michael S; Cummings, Sabrina L; Payton, Mark E

2017-11-15

OBJECTIVE To evaluate the effect of brachycephaly and body condition score on respiratory thermoregulation of healthy dogs. DESIGN Prospective study. ANIMALS 52 brachycephalic and 53 nonbrachycephalic dogs. PROCEDURES All dogs were exposed to a cool treatment (temperature, 21.8 ± 1.7°C [71.2 ± 3.1°F]; relative humidity, 62.2 ± 9.7%; and ambient enthalpy, 47.7 ± 6.6 kcal/kg) and then a hot treatment (temperature, 32.9 ± 1.7°C [91.2 ± 3.1°F]; relative humidity, 51.9 ± 9.8%; and ambient enthalpy, 74.8 ± 8.7 kcal/kg; heat stress) at least 1 hour later. For each treatment, dogs were allowed to acclimatize to the environment for 15 minutes and then were placed in a sealed whole-body plethysmograph for continuous measurement of the respiratory pattern for 10 minutes. Treatment was discontinued if a dog developed signs of respiratory distress. Respiratory variables and body temperature were compared between the 2 breed types (brachycephalic and nonbrachycephalic) and between treatments. RESULTS Body condition score was positively associated with body temperature independent of environmental conditions or breed type and negatively associated with tidal volume. Brachycephalic dogs had a greater increase in respiratory rate in response to heat stress than did nonbrachycephalic dogs. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that brachycephalic dogs had decreased capacity for thermoregulation, compared with nonbrachycephalic dogs, but body condition score was a greater determinant of body temperature than breed type. Nevertheless, both upper airway conformation and body condition score should be considered when evaluating whether an individual dog is capable of tolerating heat stress.

Fiber-optic temperature probe system for inner body

NASA Astrophysics Data System (ADS)

Liu, Bo; Deng, Xing-Zhong; Cao, Wei; Cheng, Xianping; Xie, Tuqiang; Zhong, Zugen

1991-08-01

The authors have designed a fiber-optic temperature probe system that can quickly insert its probe into bodies to measure temperature. Its thermometer unit has the function of program- controlled zeroing. The single-chip microcomputer is used to control the whole system and process data. The sample system has been tested in a coal furnace.

Apparatus and method for maintaining low temperatures about an object at a remote location

DOEpatents

Steyert, Jr., William A.; Overton, Jr., William C.

1982-01-01

The disclosure is directed to an apparatus and method for maintaining a body at cryogenic temperatures at a remote location such as down a borehole for an extended period of time. A housing contains a body comprising a material having a high specific heat at cryogenic temperatures such as between about 2 and 15 K. The body contains an orifice for containing an instrument or instruments operable at superconducting temperatures. The apparatus is precooled at the surface and lowered into a borehole to a desired depth, such as 2 to 3 miles. The instruments are operated, and the apparatus withdrawn, the material of the body maintaining the very low temperatures at which the instrument(s) operate for a sufficient period of time at the remote or downhole location. The material may comprise a rare earth compound, such as Gd.sub.2 O.sub.3, Gd.sub.2 Se.sub.3, Gd.sub.2 O.sub.2 S or GdAlO.sub.3. Monoclinic and C-phase gadolinium oxides work well. A low temperature is maintainable at a remote location for several hours.

Apparatus and method for maintaining low temperatures about an object at a remote location. [Patent application

DOEpatents

Steyert, W.A. Jr.; Overton, W.C. Jr.

1980-10-29

The disclosure is directed to an apparatus and method for maintaining a body at cryogenic temperatures at a remote location such as down a borehole for an extended period of time. A housing contains a body comprising a material having a high specific heat at cryogenic temperatures such as between about 2 and 15 K. The body contains an orifice for containing an instrument or instruments operable at superconducting temperatures. The apparatus is precooled at the surface and lowered into a borehole to a desired depth, such as 2 to 3 miles. The instruments are operated, and the apparatus withdrawn, the material of the body maintaining the very low temperatures at which the instrument(s) operate for a sufficient period of time at the remote or downhole location. The material may comprise a rare earth compound, such as Gd/sub 2/O/sub 3/, Gd/sub 2/Se/sub 3/, Gd/sub 2/O/sub 2/S or GdAlO/sub 3/. Monoclinic and C-phase gadolinium oxides work well. A low temperature is maintainable at a remote location for several hours.

From powder to solution: hydration dependence of human hemoglobin dynamics correlated to body temperature.

PubMed

Stadler, A M; Digel, I; Embs, J P; Unruh, T; Tehei, M; Zaccai, G; Büldt, G; Artmann, G M

2009-06-17

A transition in hemoglobin (Hb), involving partial unfolding and aggregation, has been shown previously by various biophysical methods. The correlation between the transition temperature and body temperature for Hb from different species, suggested that it might be significant for biological function. To focus on such biologically relevant human Hb dynamics, we studied the protein internal picosecond motions as a response to hydration, by elastic and quasielastic neutron scattering. Rates of fast diffusive motions were found to be significantly enhanced with increasing hydration from fully hydrated powder to concentrated Hb solution. In concentrated protein solution, the data showed that amino acid side chains can explore larger volumes above body temperature than expected from normal temperature dependence. The body temperature transition in protein dynamics was absent in fully hydrated powder, indicating that picosecond protein dynamics responsible for the transition is activated only at a sufficient level of hydration. A collateral result from the study is that fully hydrated protein powder samples do not accurately describe all aspects of protein picosecond dynamics that might be necessary for biological function.

Measuring the mechanical efficiency of a working cardiac muscle sample at body temperature using a flow-through calorimeter.

PubMed

Taberner, Andrew J; Johnston, Callum M; Pham, Toan; June-Chiew Han; Ruddy, Bryan P; Loiselle, Denis S; Nielsen, Poul M F

2015-08-01

We have developed a new `work-loop calorimeter' that is capable of measuring, simultaneously, the work-done and heat production of isolated cardiac muscle samples at body temperature. Through the innovative use of thermoelectric modules as temperature sensors, the development of a low-noise fluid-flow system, and implementation of precise temperature control, the heat resolution of this device is 10 nW, an improvement by a factor of ten over previous designs. These advances have allowed us to conduct the first flow-through measurements of work output and heat dissipation from cardiac tissue at body temperature. The mechanical efficiency is found to vary with peak stress, and reaches a peak value of approximately 15 %, a figure similar to that observed in cardiac muscle at lower temperatures.

Regulation of body temperature in the blue-tongued lizard.

PubMed

Hammel, H T; Caldwell, F T; Abrams, R M

1967-06-02

Lizards (Tiliqua scincoides) regulated their internal body temperature by moving back and forth between 15 degrees and 45 degrees C environments to maintain colonic and brain temperatures between 30 degrees and 37 degrees C. A pair of thermodes were implanted across the preoptic region of the brain stem, and a reentrant tube for a thermocouple was implanted in the brain stem. Heating the brain stem to 41 degrees C activated the exit response from the hot environment at a colonic temperature 1 degrees to 2 degrees C lower than normal, whereas cooling the brain stem to 25 degrees C delayed the exit from the hot environment until the colonic temperature was 1 degrees to 2 degrees C higher than normal. The behavioral thermoregulatory responses of this ectotherm appear to be activated by a combination of hypothalamic and other body temperatures.

Infrared thermal imaging for detection of peripheral vascular disorders

PubMed Central

Bagavathiappan, S.; Saravanan, T.; Philip, John; Jayakumar, T.; Raj, Baldev; Karunanithi, R.; Panicker, T. M. R.; Korath, M. Paul; Jagadeesan, K.

2009-01-01

Body temperature is a very useful parameter for diagnosing diseases. There is a definite correlation between body temperature and diseases. We have used Infrared Thermography to study noninvasive diagnosis of peripheral vascular diseases. Temperature gradients are observed in the affected regions of patients with vascular disorders, which indicate abnormal blood flow in the affected region. Thermal imaging results are well correlated with the clinical findings. Certain areas on the affected limbs show increased temperature profiles, probably due to inflammation and underlying venous flow changes. In general the temperature contrast in the affected regions is about 0.7 to 1° C above the normal regions, due to sluggish blood circulation. The results suggest that the thermal imaging technique is an effective technique for detecting small temperature changes in the human body due to vascular disorders. PMID:20126565

Contribution of garment fit and style to thermal comfort at the lower body

NASA Astrophysics Data System (ADS)

Mert, Emel; Böhnisch, Sonja; Psikuta, Agnes; Bueno, Marie-Ange; Rossi, René M.

2016-12-01

The heat and mass transfer between the human body and the environment is not only affected by the properties of the fabric, but also by the size of the air gap thickness and the magnitude of the contact area between the body and garment. In this clothing-human-environment system, there is also an interaction between the clothing and the physiological response of the wearer. Therefore, the aim of this study was to evaluate the distribution of the air gap thickness and the contact area for the male lower body in relation to the garment fit and style using a three-dimensional (3D) body scanning method with a manikin. Moreover, their relation with the physiological response of the lower body was analysed using the physiological modelling. The presented study showed that the change in the air gap thickness and the contact area due to garment fit was greater for legs than the pelvis area due to regional differences of the body. Furthermore, the garment style did not have any effect on the core temperature or total water loss of the lower body, whereas the effect of garment fit on the core temperature and total water loss of lower body was observed only for 40 °C of ambient temperature. The skin temperatures were higher for especially loose garments at thigh than the tight garments. Consequently, the results of this study indicated that the comfort level of the human body for a given purpose can be adjusted by selection of fabric type and the design of ease allowances in the garment depending on the body region.

Metallic hot wire anemometer. [for high speed wind tunnel tests

NASA Technical Reports Server (NTRS)

Lemos, F. R. (Inventor)

1977-01-01

A hot wire anemometer is described which has a body formed of heat resistant metal such as an alloy high in nickel content which supports a probe wire disposed in a V groove in the body. The V groove contains a high temperature ceramic adhesive that partially encompasses the downstream side of the probe wire. Mechanical and electrical connection to the probe wire is achieved through conductive support rods that are constructed of the same high temperature metal, insulation between the body and the conductor rods being provided by a coating of an oxide of the same material which coating is formed in situ. The oxide coating insulates the conductor rods from the body, mechanically fixes the conductors within the body, and maintains its integrity at elevated temperatures.

Thermal-safety margins and the necessity of thermoregulatory behavior across latitude and elevation

PubMed Central

Sunday, Jennifer M.; Bates, Amanda E.; Kearney, Michael R.; Colwell, Robert K.; Dulvy, Nicholas K.; Longino, John T.; Huey, Raymond B.

2014-01-01

Physiological thermal-tolerance limits of terrestrial ectotherms often exceed local air temperatures, implying a high degree of thermal safety (an excess of warm or cold thermal tolerance). However, air temperatures can be very different from the equilibrium body temperature of an individual ectotherm. Here, we compile thermal-tolerance limits of ectotherms across a wide range of latitudes and elevations and compare these thermal limits both to air and to operative body temperatures (theoretically equilibrated body temperatures) of small ectothermic animals during the warmest and coldest times of the year. We show that extreme operative body temperatures in exposed habitats match or exceed the physiological thermal limits of most ectotherms. Therefore, contrary to previous findings using air temperatures, most ectotherms do not have a physiological thermal-safety margin. They must therefore rely on behavior to avoid overheating during the warmest times, especially in the lowland tropics. Likewise, species living at temperate latitudes and in alpine habitats must retreat to avoid lethal cold exposure. Behavioral plasticity of habitat use and the energetic consequences of thermal retreats are therefore critical aspects of species’ vulnerability to climate warming and extreme events. PMID:24616528

Theoretical simulation of the dual-heat-flux method in deep body temperature measurements.

PubMed

Huang, Ming; Chen, Wenxi

2010-01-01

Deep body temperature reveals individual physiological states, and is important in patient monitoring and chronobiological studies. An innovative dual-heat-flux method has been shown experimentally to be competitive with the conventional zero-heat-flow method in its performance, in terms of measurement accuracy and step response to changes in the deep temperature. We have utilized a finite element method to model and simulate the dynamic process of a dual-heat-flux probe in deep body temperature measurements to validate the fundamental principles of the dual-heat-flux method theoretically, and to acquire a detailed quantitative description of the thermal profile of the dual-heat-flux probe. The simulation results show that the estimated deep body temperature is influenced by the ambient temperature (linearly, at a maximum rate of 0.03 °C/°C) and the blood perfusion rate. The corresponding depth of the estimated temperature in the skin and subcutaneous tissue layer is consistent when using the dual-heat-flux probe. Insights in improving the performance of the dual-heat-flux method were discussed for further studies of dual-heat-flux probes, taking into account structural and geometric considerations.

Thermal-safety margins and the necessity of thermoregulatory behavior across latitude and elevation.

PubMed

Sunday, Jennifer M; Bates, Amanda E; Kearney, Michael R; Colwell, Robert K; Dulvy, Nicholas K; Longino, John T; Huey, Raymond B

2014-04-15

Physiological thermal-tolerance limits of terrestrial ectotherms often exceed local air temperatures, implying a high degree of thermal safety (an excess of warm or cold thermal tolerance). However, air temperatures can be very different from the equilibrium body temperature of an individual ectotherm. Here, we compile thermal-tolerance limits of ectotherms across a wide range of latitudes and elevations and compare these thermal limits both to air and to operative body temperatures (theoretically equilibrated body temperatures) of small ectothermic animals during the warmest and coldest times of the year. We show that extreme operative body temperatures in exposed habitats match or exceed the physiological thermal limits of most ectotherms. Therefore, contrary to previous findings using air temperatures, most ectotherms do not have a physiological thermal-safety margin. They must therefore rely on behavior to avoid overheating during the warmest times, especially in the lowland tropics. Likewise, species living at temperate latitudes and in alpine habitats must retreat to avoid lethal cold exposure. Behavioral plasticity of habitat use and the energetic consequences of thermal retreats are therefore critical aspects of species' vulnerability to climate warming and extreme events.

Cheetah do not abandon hunts because they overheat.

PubMed

Hetem, Robyn S; Mitchell, Duncan; de Witt, Brenda A; Fick, Linda G; Meyer, Leith C R; Maloney, Shane K; Fuller, Andrea

2013-10-23

Hunting cheetah reportedly store metabolic heat during the chase and abandon chases because they overheat. Using biologging to remotely measure the body temperature (every minute) and locomotor activity (every 5 min) of four free-living cheetah, hunting spontaneously, we found that cheetah abandoned hunts, but not because they overheated. Body temperature averaged 38.4°C when the chase was terminated. Storage of metabolic heat did not compromise hunts. The increase in body temperature following a successful hunt was double that of an unsuccessful hunt (1.3°C ± 0.2°C versus 0.5°C ± 0.1°C), even though the level of activity during the hunts was similar. We propose that the increase in body temperature following a successful hunt is a stress hyperthermia, rather than an exercise-induced hyperthermia.

Cheetah do not abandon hunts because they overheat

PubMed Central

Hetem, Robyn S.; Mitchell, Duncan; de Witt, Brenda A.; Fick, Linda G.; Meyer, Leith C. R.; Maloney, Shane K.; Fuller, Andrea

2013-01-01

Hunting cheetah reportedly store metabolic heat during the chase and abandon chases because they overheat. Using biologging to remotely measure the body temperature (every minute) and locomotor activity (every 5 min) of four free-living cheetah, hunting spontaneously, we found that cheetah abandoned hunts, but not because they overheated. Body temperature averaged 38.4°C when the chase was terminated. Storage of metabolic heat did not compromise hunts. The increase in body temperature following a successful hunt was double that of an unsuccessful hunt (1.3°C ± 0.2°C versus 0.5°C ± 0.1°C), even though the level of activity during the hunts was similar. We propose that the increase in body temperature following a successful hunt is a stress hyperthermia, rather than an exercise-induced hyperthermia. PMID:23883578

Regulation of body temperature by some Mesozoic marine reptiles.

PubMed

Bernard, Aurélien; Lécuyer, Christophe; Vincent, Peggy; Amiot, Romain; Bardet, Nathalie; Buffetaut, Eric; Cuny, Gilles; Fourel, François; Martineau, François; Mazin, Jean-Michel; Prieur, Abel

2010-06-11

What the body temperature and thermoregulation processes of extinct vertebrates were are central questions for understanding their ecology and evolution. The thermophysiologic status of the great marine reptiles is still unknown, even though some studies have suggested that thermoregulation may have contributed to their exceptional evolutionary success as apex predators of Mesozoic aquatic ecosystems. We tested the thermal status of ichthyosaurs, plesiosaurs, and mosasaurs by comparing the oxygen isotope compositions of their tooth phosphate to those of coexisting fish. Data distribution reveals that these large marine reptiles were able to maintain a constant and high body temperature in oceanic environments ranging from tropical to cold temperate. Their estimated body temperatures, in the range from 35 degrees +/- 2 degrees C to 39 degrees +/- 2 degrees C, suggest high metabolic rates required for predation and fast swimming over large distances offshore.

Stress-induced behaviour in adult and old rats: effects of neonatal asphyxia, body temperature and chelation of iron.

PubMed

Rogalska, J; Caputa, M; Wentowska, K; Nowakowska, A

2006-11-01

Perinatal asphyxia in mammals leads to iron accumulation in the brain, which results in delayed neurobehavioural disturbances, including impaired learning and abnormal alertness over their entire life span. The aim of this investigation was to verify our hypothesis that newborn rats, showing reduced normal body temperature, are protected against neurotoxicity of the asphyxia up to senescence. Alertness was studied in adult and old male Wistar rats after exposure to critical neonatal anoxia: (i) at physiological neonatal body temperature of 33 degrees C, (ii) at body temperature elevated to 37 degrees C, or (iii) at body temperature elevated to 39 degrees C (the thermal conditions remained unchanged both during anoxia and for 2 h postanoxia). To elucidate the effect of iron-dependent postanoxic oxidative damage to the brain, half of the group (iii) was injected with deferoxamine, a chelator of iron. Postanoxic behavioural disturbances were recorded in open-field, elevated plus-maze, and sudden silence tests when the rats reached the age of 12 and 24 months. Open-field stress-induced motor activity was reduced in rats subjected to neonatal anoxia under hyperthermic conditions. In contrast, these rats were hyperactive in the plus-maze test. Both the plus-maze and sudden silence tests show reduced alertness of these rats to external stimuli signalling potential dangers. The behavioural disturbances were prevented by body temperature of 33 degrees C and by administration of deferoxamine.

Behavior and survival of Mytilus congeners following episodes of elevated body temperature in air and seawater.

PubMed

Dowd, W Wesley; Somero, George N

2013-02-01

Coping with environmental stress may involve combinations of behavioral and physiological responses. We examined potential interactions between adult mussels' simple behavioral repertoire - opening/closing of the shell valves - and thermal stress physiology in common-gardened individuals of three Mytilus congeners found on the West Coast of North America: two native species (M. californianus and M. trossulus) and one invasive species from the Mediterranean (M. galloprovincialis). We first continuously monitored valve behavior over three consecutive days on which body temperatures were gradually increased, either in air or in seawater. A temperature threshold effect was evident between 25 and 33°C in several behavioral measures. Mussels tended to spend much less time with the valves in a sealed position following exposure to 33°C body temperature, especially when exposed in air. This behavior could not be explained by decreases in adductor muscle glycogen (stores of this metabolic fuel actually increased in some scenarios), impacts of forced valve sealing on long-term survival (none observed in a second experiment), or loss of contractile function in the adductor muscles (individuals exhibited as many or more valve adduction movements following elevated body temperature compared with controls). We hypothesize that this reduced propensity to seal the valves following thermal extremes represents avoidance of hypoxia-reoxygenation cycles and concomitant oxidative stress. We further conjecture that prolonged valve gaping following episodes of elevated body temperature may have important ecological consequences by affecting species interactions. We then examined survival over a 90 day period following exposure to elevated body temperature and/or emersion, observing ongoing mortality throughout this monitoring period. Survival varied significantly among species (M. trossulus had the lowest survival) and among experimental contexts (survival was lowest after experiencing elevated body temperature in seawater). Surprisingly, we observed no cumulative impact on survival of 3 days relative to 1 day of exposure to elevated body temperature. The delayed mortality and context-specific outcomes we observed have important implications for the design of future experiments and for interpretation of field distribution patterns of these species. Ultimately, variation in the catalog of physiological and behavioral capacities among closely related or sympatric species is likely to complicate prediction of the ecological consequences of global change and species invasions.

Rheological investigation of body cream and body lotion in actual application conditions

NASA Astrophysics Data System (ADS)

Kwak, Min-Sun; Ahn, Hye-Jin; Song, Ki-Won

2015-08-01

The objective of the present study is to systematically evaluate and compare the rheological behaviors of body cream and body lotion in actual usage situations. Using a strain-controlled rheometer, the steady shear flow properties of commercially available body cream and body lotion were measured over a wide range of shear rates, and the linear viscoelastic properties of these two materials in small amplitude oscillatory shear flow fields were measured over a broad range of angular frequencies. The temperature dependency of the linear viscoelastic behaviors was additionally investigated over a temperature range most relevant to usual human life. The main findings obtained from this study are summarized as follows: (1) Body cream and body lotion exhibit a finite magnitude of yield stress. This feature is directly related to the primary (initial) skin feel that consumers usually experience during actual usage. (2) Body cream and body lotion exhibit a pronounced shear-thinning behavior. This feature is closely connected with the spreadability when cosmetics are applied onto the human skin. (3) The linear viscoelastic behaviors of body cream and body lotion are dominated by an elastic nature. These solid-like properties become a criterion to assess the selfstorage stability of cosmetic products. (4) A modified form of the Cox-Merz rule provides a good ability to predict the relationship between steady shear flow and dynamic viscoelastic properties for body cream and body lotion. (5) The storage modulus and loss modulus of body cream show a qualitatively similar tendency to gradually decrease with an increase in temperature. In the case of body lotion, with an increase in temperature, the storage modulus is progressively decreased while the loss modulus is slightly increased and then decreased. This information gives us a criterion to judge how the characteristics of cosmetic products are changed by the usual human environments.

Incubation temperature influences trade-off between structural size and energy reserves in mallard hatchlings.

PubMed

Koláčková, Martina; Prokůpková, Ludmila; Albrecht, Tomáš; Hořák, David

2015-01-01

The reproductive success of precocial birds depends on investments in clutch formation and incubation. Egg quality strongly affects the phenotypic traits correlated with survival of the hatchling, but parental ability to maintain incubation temperature can also influence hatchling outcomes. The effect of incubation temperature on hatchling phenotype has been widely studied in reptiles but not in birds. The aim of this study was to explore the effects of egg mass and incubation temperature on the incubation period, hatchability, and hatchling phenotype of the mallard (Anas platyrhynchos). Mallard eggs were incubated under six constant incubation temperatures (ranging from 35.0° to 39.0°C). Hatchlings were weighed, and their structural size was measured. Some hatchlings were used for an examination of residual yolk sac mass and basic chemical composition of the yolk-free body. All investigated phenotypic traits except for chemical composition were positively correlated with egg mass. Incubation temperature did not affect hatchling body mass, but increased temperatures led to a decreased yolk-free body mass and structural size of hatchlings and to increased yolk sac mass. Our results suggest that there is a trade-off between the yolk-free body size and energetic reserves in the form of the yolk sac and that this trade-off is modulated by incubation temperature.

The role of PDF neurons in setting the preferred temperature before dawn in Drosophila.

PubMed

Tang, Xin; Roessingh, Sanne; Hayley, Sean E; Chu, Michelle L; Tanaka, Nobuaki K; Wolfgang, Werner; Song, Seongho; Stanewsky, Ralf; Hamada, Fumika N

2017-05-02

Animals have sophisticated homeostatic controls. While mammalian body temperature fluctuates throughout the day, small ectotherms, such as Drosophila achieve a body temperature rhythm (BTR) through their preference of environmental temperature. Here, we demonstrate that pigment dispersing factor (PDF) neurons play an important role in setting preferred temperature before dawn. We show that small lateral ventral neurons (sLNvs), a subset of PDF neurons, activate the dorsal neurons 2 (DN2s), the main circadian clock cells that regulate temperature preference rhythm (TPR). The number of temporal contacts between sLNvs and DN2s peak before dawn. Our data suggest that the thermosensory anterior cells (ACs) likely contact sLNvs via serotonin signaling. Together, the ACs-sLNs-DN2s neural circuit regulates the proper setting of temperature preference before dawn. Given that sLNvs are important for sleep and that BTR and sleep have a close temporal relationship, our data highlight a possible neuronal interaction between body temperature and sleep regulation.

Temperature regulates splicing efficiency of the cold-inducible RNA-binding protein gene Cirbp

PubMed Central

Gotic, Ivana; Omidi, Saeed; Fleury-Olela, Fabienne; Molina, Nacho; Naef, Felix; Schibler, Ueli

2016-01-01

In mammals, body temperature fluctuates diurnally around a mean value of 36°C–37°C. Despite the small differences between minimal and maximal values, body temperature rhythms can drive robust cycles in gene expression in cultured cells and, likely, animals. Here we studied the mechanisms responsible for the temperature-dependent expression of cold-inducible RNA-binding protein (CIRBP). In NIH3T3 fibroblasts exposed to simulated mouse body temperature cycles, Cirbp mRNA oscillates about threefold in abundance, as it does in mouse livers. This daily mRNA accumulation cycle is directly controlled by temperature oscillations and does not depend on the cells’ circadian clocks. Here we show that the temperature-dependent accumulation of Cirbp mRNA is controlled primarily by the regulation of splicing efficiency, defined as the fraction of Cirbp pre-mRNA processed into mature mRNA. As revealed by genome-wide “approach to steady-state” kinetics, this post-transcriptional mechanism is widespread in the temperature-dependent control of gene expression. PMID:27633015

Long-term, high frequency in situ measurements of intertidal mussel bed temperatures using biomimetic sensors

PubMed Central

Helmuth, Brian; Choi, Francis; Matzelle, Allison; Torossian, Jessica L.; Morello, Scott L.; Mislan, K.A.S.; Yamane, Lauren; Strickland, Denise; Szathmary, P. Lauren; Gilman, Sarah E.; Tockstein, Alyson; Hilbish, Thomas J.; Burrows, Michael T.; Power, Anne Marie; Gosling, Elizabeth; Mieszkowska, Nova; Harley, Christopher D.G.; Nishizaki, Michael; Carrington, Emily; Menge, Bruce; Petes, Laura; Foley, Melissa M.; Johnson, Angela; Poole, Megan; Noble, Mae M.; Richmond, Erin L.; Robart, Matt; Robinson, Jonathan; Sapp, Jerod; Sones, Jackie; Broitman, Bernardo R.; Denny, Mark W.; Mach, Katharine J.; Miller, Luke P.; O’Donnell, Michael; Ross, Philip; Hofmann, Gretchen E.; Zippay, Mackenzie; Blanchette, Carol; Macfarlan, J.A.; Carpizo-Ituarte, Eugenio; Ruttenberg, Benjamin; Peña Mejía, Carlos E.; McQuaid, Christopher D.; Lathlean, Justin; Monaco, Cristián J.; Nicastro, Katy R.; Zardi, Gerardo

2016-01-01

At a proximal level, the physiological impacts of global climate change on ectothermic organisms are manifest as changes in body temperatures. Especially for plants and animals exposed to direct solar radiation, body temperatures can be substantially different from air temperatures. We deployed biomimetic sensors that approximate the thermal characteristics of intertidal mussels at 71 sites worldwide, from 1998-present. Loggers recorded temperatures at 10–30 min intervals nearly continuously at multiple intertidal elevations. Comparisons against direct measurements of mussel tissue temperature indicated errors of ~2.0–2.5 °C, during daily fluctuations that often exceeded 15°–20 °C. Geographic patterns in thermal stress based on biomimetic logger measurements were generally far more complex than anticipated based only on ‘habitat-level’ measurements of air or sea surface temperature. This unique data set provides an opportunity to link physiological measurements with spatially- and temporally-explicit field observations of body temperature. PMID:27727238

Long-term, high frequency in situ measurements of intertidal mussel bed temperatures using biomimetic sensors

NASA Astrophysics Data System (ADS)

Helmuth, Brian; Choi, Francis; Matzelle, Allison; Torossian, Jessica L.; Morello, Scott L.; Mislan, K. A. S.; Yamane, Lauren; Strickland, Denise; Szathmary, P. Lauren; Gilman, Sarah E.; Tockstein, Alyson; Hilbish, Thomas J.; Burrows, Michael T.; Power, Anne Marie; Gosling, Elizabeth; Mieszkowska, Nova; Harley, Christopher D. G.; Nishizaki, Michael; Carrington, Emily; Menge, Bruce; Petes, Laura; Foley, Melissa M.; Johnson, Angela; Poole, Megan; Noble, Mae M.; Richmond, Erin L.; Robart, Matt; Robinson, Jonathan; Sapp, Jerod; Sones, Jackie; Broitman, Bernardo R.; Denny, Mark W.; Mach, Katharine J.; Miller, Luke P.; O'Donnell, Michael; Ross, Philip; Hofmann, Gretchen E.; Zippay, Mackenzie; Blanchette, Carol; Macfarlan, J. A.; Carpizo-Ituarte, Eugenio; Ruttenberg, Benjamin; Peña Mejía, Carlos E.; McQuaid, Christopher D.; Lathlean, Justin; Monaco, Cristián J.; Nicastro, Katy R.; Zardi, Gerardo

2016-10-01

At a proximal level, the physiological impacts of global climate change on ectothermic organisms are manifest as changes in body temperatures. Especially for plants and animals exposed to direct solar radiation, body temperatures can be substantially different from air temperatures. We deployed biomimetic sensors that approximate the thermal characteristics of intertidal mussels at 71 sites worldwide, from 1998-present. Loggers recorded temperatures at 10-30 min intervals nearly continuously at multiple intertidal elevations. Comparisons against direct measurements of mussel tissue temperature indicated errors of ~2.0-2.5 °C, during daily fluctuations that often exceeded 15°-20 °C. Geographic patterns in thermal stress based on biomimetic logger measurements were generally far more complex than anticipated based only on ‘habitat-level’ measurements of air or sea surface temperature. This unique data set provides an opportunity to link physiological measurements with spatially- and temporally-explicit field observations of body temperature.

Seasonal reproductive endothermy in tegu lizards.

PubMed

Tattersall, Glenn J; Leite, Cleo A C; Sanders, Colin E; Cadena, Viviana; Andrade, Denis V; Abe, Augusto S; Milsom, William K

2016-01-01

With some notable exceptions, small ectothermic vertebrates are incapable of endogenously sustaining a body temperature substantially above ambient temperature. This view was challenged by our observations of nighttime body temperatures sustained well above ambient (up to 10°C) during the reproductive season in tegu lizards (~2 kg). This led us to hypothesize that tegus have an enhanced capacity to augment heat production and heat conservation. Increased metabolic rates and decreased thermal conductance are the same mechanisms involved in body temperature regulation in those vertebrates traditionally acknowledged as "true endotherms": the birds and mammals. The appreciation that a modern ectotherm the size of the earliest mammals can sustain an elevated body temperature through metabolic rates approaching that of endotherms enlightens the debate over endothermy origins, providing support for the parental care model of endothermy, but not for the assimilation capacity model of endothermy. It also indicates that, contrary to prevailing notions, ectotherms can engage in facultative endothermy, providing a physiological analog in the evolutionary transition to true endothermy.

Temperature and behavioral responses of squirrel monkeys to 2Gz acceleration

NASA Technical Reports Server (NTRS)

Fuller, C. A.; Tremor, J.; Connolly, J. P.; Williams, B. A.

1982-01-01

This study examines the responses of squirrel monkeys to acute +2Gz exposure. Body temperature responses of loosely restrained animals were recorded via a thermistor in the colon. Behavioral responses were recorded by video monitoring. After baseline recording at 1G, monkeys were exposed to 2G for 60 min. The body temperature started to fall within 10 min of the onset of centrifugation and declined an average of 1.4 C in 60 min. This is in contrast to a stable body temperature during the control period. Further, after a few minutes at 2G, the animals became drowsy and appeared to fall asleep. During the control period, however, they were alert and continually shifting their gaze about the cage. Thus, primates are susceptible to hypergravic fields in the +Gz orientation. The depression in primate body temperature was consistent and significant. Further, the observed drowsiness in this study has significant ramifications regarding alertness and performance in man.

Seasonal reproductive endothermy in tegu lizards

PubMed Central

Tattersall, Glenn J.; Leite, Cleo A. C.; Sanders, Colin E.; Cadena, Viviana; Andrade, Denis V.; Abe, Augusto S.; Milsom, William K.

2016-01-01

With some notable exceptions, small ectothermic vertebrates are incapable of endogenously sustaining a body temperature substantially above ambient temperature. This view was challenged by our observations of nighttime body temperatures sustained well above ambient (up to 10°C) during the reproductive season in tegu lizards (~2 kg). This led us to hypothesize that tegus have an enhanced capacity to augment heat production and heat conservation. Increased metabolic rates and decreased thermal conductance are the same mechanisms involved in body temperature regulation in those vertebrates traditionally acknowledged as “true endotherms”: the birds and mammals. The appreciation that a modern ectotherm the size of the earliest mammals can sustain an elevated body temperature through metabolic rates approaching that of endotherms enlightens the debate over endothermy origins, providing support for the parental care model of endothermy, but not for the assimilation capacity model of endothermy. It also indicates that, contrary to prevailing notions, ectotherms can engage in facultative endothermy, providing a physiological analog in the evolutionary transition to true endothermy. PMID:26844295

The Physiological Basis for Thermal Comfort in Different Climates; a Preliminary Study (De fysiologische basis voor thermisch comfort onder diverse klimatologische omstandigheden; een voorstudie),

DTIC Science & Technology

1996-08-07

Thermal comfort is very important for optimal functioning of humans. It gives information about the thermal state of the body, by which the human...receptors and sending efferent information to the effectors by which the body controls its temperature. Thermal comfort is determined by the temperature...global thermal comfort are core temperature, temperature of the extremities and temperature of the environment. In local thermal comfort and pain

Relationship of blood corticosterone, immunoglobulin and haematological values in young crocodiles (Crocodylus porosus) to water temperature, clutch of origin and body weight.

PubMed

Turton, J A; Ladds, P W; Manolis, S C; Webb, G J

1997-02-01

To examine whether sub-optimal temperature induced stress and immunosuppression in farmed saltwater crocodile (Crocodylus porosus) hatchlings. A clinico-pathological study. A total of 140 hatchlings were used. Body weight and length, plasma corticosterone and immunoglobulin concentrations and total and differential white blood cell counts were measured in 140 hatchlings from five clutches divided between five water temperature treatment groups. Initially all groups were housed at 32 degrees C for 10 weeks, then two groups (L, LC) were changed to low temperature (28 degrees C) and two groups (H, HC) to high temperature (36 degrees C), while one group (C) remained at 32 degrees C. The LC and HC groups were maintained at these temperatures for 10 days, after which the water temperature of both groups was returned to 32 degrees C. Blood samples were collected twice (at 6 and 9 weeks of age) before the initial temperature change, and at 10 days and 4 weeks after the initial temperature change (at 11.5 and 14 weeks of age). Except for an increase in plasma corticosterone in the HC group and a decrease in the L group when the temperature change was first introduced, changes in plasma corticosterone were not significant. There were no significant changes in immunoglobulin concentrations. There were, however, significant decreases in the total white cell and lymphocyte counts in the LC group after the temperature was decreased to 28 degrees C, and an increase in these counts after water temperature was returned to 32 degrees C. Clutch of origin had significant effects on body weight and length gains, and there were negative relationships between body weight and corticosterone concentrations and between body weight and immunoglobulin concentrations. As haematological changes indicative of stress were not associated with significant changes in serum corticosterone, immunosuppression in young crocodiles may be independent of the hypothalamic-pituitary-adrenal cortical axis.

Pregnant women maintain body temperatures within safe limits during moderate-intensity aqua-aerobic classes conducted in pools heated up to 33 degrees Celsius: an observational study.

PubMed

Brearley, Amanda L; Sherburn, Margaret; Galea, Mary P; Clarke, Sandy J

2015-10-01

What is the body temperature response of healthy pregnant women exercising at moderate intensity in an aqua-aerobics class where the water temperature is in the range of 28 to 33 degrees Celsius, as typically found in community swimming pools? An observational study. One hundred and nine women in the second and third trimester of pregnancy who were enrolled in a standardised aqua-aerobics class. Tympanic temperature was measured at rest pre-immersion (T1), after 35minutes of moderate-intensity aqua-aerobic exercise (T2), after a further 10minutes of light exercise while still in the water (T3) and finally on departure from the facility (T4). The range of water temperatures in seven indoor community pools was 28.8 to 33.4 degrees Celsius. Body temperature increased by a mean of 0.16 degrees Celsius (SD 0.35, p<0.001) at T2, was maintained at this level at T3 and had returned to pre-immersion resting values at T4. Regression analysis demonstrated that the temperature response was not related to the water temperature (T2 r = -0.01, p = 0.9; T3 r = -0.02, p=0.9; T4 r=0.03, p=0.8). Analysis of variance demonstrated no difference in body temperature response between participants when grouped in the cooler, medium and warmer water temperatures (T2 F=0.94, p=0.40; T3 F=0.93, p=0.40; T4 F=0.70, p=0.50). Healthy pregnant women maintain body temperatures within safe limits during moderate-intensity aqua-aerobic exercise conducted in pools heated up to 33 degrees Celsius. The study provides evidence to inform guidelines for safe water temperatures for aqua-aerobic exercise during pregnancy. Copyright © 2015 Australian Physiotherapy Association. Published by Elsevier B.V. All rights reserved.

Thermodynamics of the living organisms. Allometric relationship between the total metabolic energy, chemical energy and body temperature in mammals

NASA Astrophysics Data System (ADS)

Atanasov, Atanas Todorov

2017-11-01

The study present relationship between the total metabolic energy (ETME(c), J) derived as a function of body chemical energy (Gchem, J) and absolute temperature (Tb, K) in mammals: ETME(c) =Gchem (Tb/Tn). In formula the temperature Tn =2.73K appears normalization temperature. The calculated total metabolic energy ETME(c) differs negligible from the total metabolic energy ETME(J), received as a product between the basal metabolic rate (Pm, J/s) and the lifespan (Tls, s) of mammals: ETME = Pm×Tls. The physical nature and biological mean of the normalization temperature (Tn, K) is unclear. It is made the hypothesis that the kTn energy (where k= 1.3806×10-23 J/K -Boltzmann constant) presents energy of excitation states (modes) in biomolecules and body structures that could be in equilibrium with chemical energy accumulated in body. This means that the accumulated chemical energy allows trough all body molecules and structures to propagate excitations states with kTn energy with wavelength in the rage of width of biological membranes. The accumulated in biomolecules chemical energy maintains spread of the excited states through biomolecules without loss of energy.

Evaluating thermoregulation in reptiles: an appropriate null model.

PubMed

Christian, Keith A; Tracy, Christopher R; Tracy, C Richard

2006-09-01

Established indexes of thermoregulation in ectotherms compare body temperatures of real animals with a null distribution of operative temperatures from a physical or mathematical model with the same size, shape, and color as the actual animal but without mass. These indexes, however, do not account for thermal inertia or the effects of inertia when animals move through thermally heterogeneous environments. Some recent models have incorporated body mass, to account for thermal inertia and the physiological control of warming and cooling rates seen in most reptiles, and other models have incorporated movement through the environment, but none includes all pertinent variables explaining body temperature. We present a new technique for calculating the distribution of body temperatures available to ectotherms that have thermal inertia, random movements, and different rates of warming and cooling. The approach uses a biophysical model of heat exchange in ectotherms and a model of random interaction with thermal environments over the course of a day to create a null distribution of body temperatures that can be used with conventional thermoregulation indexes. This new technique provides an unbiased method for evaluating thermoregulation in large ectotherms that store heat while moving through complex environments, but it can also generate null models for ectotherms of all sizes.

Variation of thermal parameters in two different color morphs of a diurnal poison toad, Melanophryniscus rubriventris (Anura: Bufonidae).

PubMed

Sanabria, Eduardo A; Vaira, Marcos; Quiroga, Lorena B; Akmentins, Mauricio S; Pereyra, Laura C

2014-04-01

We study the variation in thermal parameters in two contrasting populations Yungas Redbelly Toads (Melanophryniscus rubriventris) with different discrete color phenotypes comparing field body temperatures, critical thermal maximum and heating rates. We found significant differences in field body temperatures of the different morphs. Temperatures were higher in toads with a high extent of dorsal melanization. No variation was registered in operative temperatures between the study locations at the moment of capture and processing. Critical thermal maximum of toads was positively related with the extent of dorsal melanization. Furthermore, we founded significant differences in heating rates between morphs, where individuals with a high extent of dorsal melanization showed greater heating rates than toads with lower dorsal melanization. The color pattern-thermal parameter relationship observed may influence the activity patterns and body size of individuals. Body temperature is a modulator of physiological and behavioral functions in amphibians, influencing daily and seasonal activity, locomotor performance, digestion rate and growth rate. It is possible that some growth constraints may arise due to the relationship of color pattern-metabolism allowing different morphs to attain similar sizes at different locations instead of body-size clines. Copyright © 2014. Published by Elsevier Ltd.

Opioid, cannabinoid, and transient receptor potential (TRP) systems: effects on body temperature

PubMed Central

Rawls, Scott M.; Benamar, Khalid

2014-01-01

Cannabinoid and opioid drugs produce marked changes in body temperature. Recent findings have extended our knowledge about the thermoregulatory effects of cannabinoids and opioids, particularly as related to delta opioid receptors, endogenous systems, and transient receptor potential (TRP) channels. Although delta opioid receptors were originally thought to play only a minor role in thermoregulation compared to mu and kappa opioid receptors, their activation has been shown to produce hypothermia in multiple species. Endogenous opioids and cannabinoids also regulate body temperature. Mu and kappa opioid receptors are thought to be in tonic balance, with mu and kappa receptor activation producing hyperthermia and hypothermia, respectively. Endocannabinoids participate in the febrile response, but more studies are needed to determine if a cannabinoid CB1 receptor tone exerts control over basal body temperature. A particularly intense research focus is TRP channels, where TRPV1 channel activation produces hypothermia whereas TRPA1 and TRPM8 channel activation causes hyperthermia. The marked hyperthermia produced by TRPV1 channel antagonists suggests these warm channels tonically control body temperature. A better understanding of the roles of cannabinoid, opioid, and TRP systems in thermoregulation may have broad clinical implications and provide insights into interactions among neurotransmitter systems involved in thermoregulation. PMID:21622235

Behavioural thermoregulation and the relative roles of convection and radiation in a basking butterfly.

PubMed

Barton, Madeleine; Porter, Warren; Kearney, Michael

2014-04-01

Poikilothermic animals are often reliant on behavioural thermoregulation to elevate core-body temperature above the temperature of their surroundings. Butterflies are able to do this by altering body posture and location while basking, however the specific mechanisms that achieve such regulation vary among species. The role of the wings has been particularly difficult to describe, with uncertainty surrounding whether they are positioned to reduce convective heat loss or to maximise heat gained through radiation. Characterisation of the extent to which these processes affect core-body temperature will provide insights into the way in which a species׳ thermal sensitivity and morphological traits have evolved. We conducted field and laboratory measurements to assess how basking posture affects the core-body temperature of an Australian butterfly, the common brown (Heteronympha merope). We show that, with wings held open, heat lost through convection is reduced while heat gained through radiation is simultaneously maximised. These responses have been incorporated into a biophysical model that accurately predicts the core-body temperature of basking specimens in the field, providing a powerful tool to explore how climate constrains the distribution and abundance of basking butterflies. Copyright © 2014 Elsevier Ltd. All rights reserved.

Multiple parent bodies of ordinary chondrites

NASA Technical Reports Server (NTRS)

Yomogida, K.; Matsui, T.

1984-01-01

Thermal histories of chondrite parent bodies are calculated from an initial state with material in a powder-like form, taking into account the effect of consolidation state on thermal conductivity. The very low thermal conductivity of the starting materials makes it possible for a small body with a radius of less than 100 km to be heated by several hundred degrees even if long-lived radioactive elements in chondritic abundances are the only source of heat. The maximum temperature is determined primarily by the temperature at which sintering of the constituent materials occurs. The thermal state of the interior of a chondrite parent body after sintering has begun is nearly isothermal. Near the surface, however, where the material is unconsolidated and the thermal conductivity is much lower, the thermal gradient is quite large. This result contradicts the conventional 'onion-shell' model of chondrite parent bodies. But because the internal temperature is almost constant through the whole body, it supports a 'multiple-parent bodies' model, according to which each petrologic type of chondrite comes from a different parent body.

Metabolism and thermoregulation during fasting in king penguins, Aptenodytes patagonicus, in air and water.

PubMed

Fahlman, A; Schmidt, A; Handrich, Y; Woakes, A J; Butler, P J

2005-09-01

We measured oxygen consumption rate (Vo(2)) and body temperatures in 10 king penguins in air and water. Vo(2) was measured during rest and at submaximal and maximal exercise before (fed) and after (fasted) an average fasting duration of 14.4 +/- 2.3 days (mean +/- 1 SD, range 10-19 days) in air and water. Concurrently, we measured subcutaneous temperature and temperature of the upper (heart and liver), middle (stomach) and lower (intestine) abdomen. The mean body mass (M(b)) was 13.8 +/- 1.2 kg in fed and 11.0 +/- 0.6 kg in fasted birds. After fasting, resting Vo(2) was 93% higher in water than in air (air: 86.9 +/- 8.8 ml/min; water: 167.3 +/- 36.7 ml/min, P < 0.01), while there was no difference in resting Vo(2) between air and water in fed animals (air: 117.1 +/- 20.0 ml O(2)/min; water: 114.8 +/- 32.7 ml O(2)/min, P > 0.6). In air, Vo(2) decreased with M(b), while it increased with M(b) in water. Body temperature did not change with fasting in air, whereas in water, there were complex changes in the peripheral body temperatures. These latter changes may, therefore, be indicative of a loss in body insulation and of variations in peripheral perfusion. Four animals were given a single meal after fasting and the temperature changes were partly reversed 24 h after refeeding in all body regions except the subcutaneous, indicating a rapid reversal to a prefasting state where body heat loss is minimal. The data emphasize the importance in considering nutritional status when studying king penguins and that the fasting-related physiological changes diverge in air and water.

Adiponectin is required for maintaining normal body temperature in a cold environment.

PubMed

Wei, Qiong; Lee, Jong Han; Wang, Hongying; Bongmba, Odelia Y N; Wu, Chia-Shan; Pradhan, Geetali; Sun, Zilin; Chew, Lindsey; Bajaj, Mandeep; Chan, Lawrence; Chapkin, Robert S; Chen, Miao-Hsueh; Sun, Yuxiang

2017-10-23

Thermogenic impairment promotes obesity and insulin resistance. Adiponectin is an important regulator of energy homeostasis. While many beneficial metabolic effects of adiponectin resemble that of activated thermogenesis, the role of adiponectin in thermogenesis is not clear. In this study, we investigated the role of adiponectin in thermogenesis using adiponectin-null mice (Adipoq -/- ). Body composition was measured using EchoMRI. Metabolic parameters were determined by indirect calorimetry. Insulin sensitivity was evaluated by glucose- and insulin- tolerance tests. Core body temperature was measured by a TH-8 temperature monitoring system. Gene expression was assessed by real-time PCR and protein levels were analyzed by Western blotting and immunohistochemistry. The mitochondrial density of brown adipose tissue was quantified by calculating the ratio of mtDNA:total nuclear DNA. Under normal housing temperature of 24 °C and ad libitum feeding condition, the body weight, body composition, and metabolic profile of Adipoq -/- mice were unchanged. Under fasting condition, Adipoq -/- mice exhibited reduced energy expenditure. Conversely, under cold exposure, Adipoq -/- mice exhibited reduced body temperature, and the expression of thermogenic regulatory genes was significantly reduced in brown adipose tissue (BAT) and subcutaneous white adipose tissue (WAT). Moreover, we observed that mitochondrial content was reduced in BAT and subcutaneous WAT, and the expression of mitochondrial fusion genes was decreased in BAT of Adipoq -/- mice, suggesting that adiponectin ablation diminishes mitochondrial biogenesis and altered mitochondrial dynamics. Our study further revealed that adiponectin deletion suppresses adrenergic activation, and down-regulates β3-adrenergic receptor, insulin signaling, and the AMPK-SIRT1 pathway in BAT. Our findings demonstrate that adiponectin is an essential regulator of thermogenesis, and adiponectin is required for maintaining body temperature under cold exposure.

Normal range and lateral symmetry in the skin temperature profile of pregnant women

NASA Astrophysics Data System (ADS)

Pereira, Tânia; Nogueira-Silva, Cristina; Simoes, Ricardo

2016-09-01

Body skin temperature is a useful parameter for diagnosing diseases and infrared thermography can be a powerful tool in providing important information to detect body temperature changes in a noninvasive way. The aim of this work was to study the pattern of skin temperature during pregnancy, to establish skin temperature reference values and to find correlations between these and the pregnant population characteristics. Sixty-one healthy pregnant women (mean age 30.6 ± 5.1 years) in the 8th-40th gestational week with normal pregnancies were examined in 31 regions of interest (ROI). The ROIs were defined all over the body in order to determine the most influenced by factors such as age or body mass index (BMI). The results obtained in this work highlight that in normal pregnant women the skin temperature is symmetrically distributed, with the symmetrical areas differing less than 0.5 °C , with a mean value of 0.25 ± 0.23 °C . This study identified a significant negative correlation between the BMI and temperature. Age has been shown to have great influence on the skin temperature, with a significant increase of temperature observed with age. This work explores a novel medical application of infrared thermography and provides a characterization of thermal skin profile in human pregnancy for a large set of ROIs while also evaluating the effects of age and BMI.

Order-picking in deep cold--physiological responses of younger and older females. Part 2: body core temperature and skin surface temperature.

PubMed

Baldus, Sandra; Kluth, Karsten; Strasser, Helmut

2012-01-01

So far, it was unclear to what extent working in deep cold-storage depots has an influence on female order-pickers body core temperature and skin surface temperature considering different age groups. Physiological effects of order-picking in a chill room (+3°C) and cold store (-24°C) were examined on 30 female subjects (Ss), classified in two age groups (20- to 35- year-olds and 40- to 65-year-olds). The body core temperature was taken every 15 min at the tympanum and the skin surface temperature was recorded continuously at seven different positions. Working in the chill room induced a decrease of the body core temperature up to 0.5K in comparison to the value at the outset for both age groups which could be compensated by all Ss during the breaks. Working in the cold store caused a decline up to 1.1K for the younger Ss and 1.3K for the older Ss. A complete warming-up during the breaks was often not possible. Regarding the skin surface temperature, working in the chill room can be considered as unproblematic, whereas significantly lower temperatures at nose, fingers and toes, associated with substantial negative subjective sensations, were recorded while working in the cold store.

A systematic review of body temperature variations in older people.

PubMed

Lu, Shu-Hua; Leasure, Angela-Renee; Dai, Yu-Tzu

2010-01-01

The purpose of this systematic review was to determine the extent to which the research literature indicates body temperature norms in the geriatric population. The specific questions addressed were to examine normal body temperature values in persons 60 years of age and older; determine differences in temperature values depending on non-invasive measurement site and measurement device used; and, examine the degree and extent of temperature variability according to time of day and time of year. The traditional 'normal' temperature of 98.6 degrees F/37 degrees C may in fact be lower in older people due to the ageing process. Age-associated changes in vasomotor sweating function, skeletal muscle response, temperature perception and physical behaviours may influence the ability to maintain optimum temperature. A systematic literature review. A search of multiple databases yielded 22 papers which met inclusion criteria. Studies were included which focused on temperature measurement, sampled persons 60 years of age and older, collected data from non-invasive temperature measurement sites and which used a prospective study design. Studies were independently appraised using a structured appraisal format. Temperature normal values by site were rectal 98.8 degrees F/37.1 degrees C, ear-based 98.3 degrees F/36.8 degrees C, urine 97.6 degrees F/36.5 degrees C, oral 97.4 degrees F/36.3 degrees C and axillary 97.1 degrees F/36.2 degrees C. Temperature exhibited a 0.7 degrees F/0.4 degrees C diurnal and 0.2 degrees F/0.1 degrees C circannual variation. Synthesis of data indicated that normal body temperature values in older people by sites were rectal 0.7 degrees F/0.4 degrees C, ear-based 0.3 degrees F/0.2 degrees C, oral 1.2 degrees F/0.7 degrees C, axillary 0.6 degrees F/0.3 degrees C lower than adults' acceptable value from those traditionally found in nursing textbooks. Given the fact that normal body temperature values were consistently lower than values reported in the literature, clinicians may need to re-evaluate the point at which interventions for abnormal temperatures are initiated.

Body temperature rhythm and control of the time of the best physical condition by performing physical labor.

PubMed

Imafuku, Michio

2016-01-01

The initial examination of a male subject's body temperature revealed that it was highest during the evening. Based on this observation, I measured grasping power, calculation speed, performance time on a light sensory task and body temperature, all of which were highest or best during the evening. The time of this subject's best physical condition shifted from the evening to morning hours when the subject executed hard physical labor in the morning, and the shifted phase was maintained after the termination of the labor period.

Influence of hypo- and hyperthermia on death time estimation - A simulation study.

PubMed

Muggenthaler, H; Hubig, M; Schenkl, S; Mall, G

2017-09-01

Numerous physiological and pathological mechanisms can cause elevated or lowered body core temperatures. Deviations from the physiological level of about 37°C can influence temperature based death time estimations. However, it has not been investigated by means of thermodynamics, to which extent hypo- and hyperthermia bias death time estimates. Using numerical simulation, the present study investigates the errors inherent in temperature based death time estimation in case of elevated or lowered body core temperatures before death. The most considerable errors with regard to the normothermic model occur in the first few hours post-mortem. With decreasing body core temperature and increasing post-mortem time the error diminishes and stagnates at a nearly constant level. Copyright © 2017 Elsevier B.V. All rights reserved.

Transcriptome analysis of the Bombyx mori fat body after constant high temperature treatment shows differences between the sexes.

PubMed

Wang, Hua; Fang, Yan; Wang, Lipeng; Zhu, Wenjuan; Ji, Haipeng; Wang, Haiying; Xu, Shiqing; Sima, Yanghu

2014-09-01

Ambient temperature plays a large role in insect growth, development and even their distribution. The elucidation of the associated molecular mechanism that underlies the effect of constant high temperature will enables us to further understand the stress responses. We constructed four digital gene expression libraries from the fat body of female and male Bombyx mori. Differential gene expression was analyzed after constant high temperature treatment. The results showed that there were significant changes to the gene expression in the fat body after heat treatment, especially in binding, catalytic, cellular and metabolic processes. Constant high temperature may induce more traditional cryoprotectants, such as glycerol, glycogen, sorbitol and lipids, to protect cells from damage, and induce heat oxidative stress in conjunction with the heat shock proteins. The data also indicated a difference between males and females. The heat shock protein-related genes were up-regulated in both sexes but the expression of Hsp25.4 and DnaJ5 were down-regulated in the male fat body of B. mori. This is the first report of such a result. Constant high temperature also affected the expression of other functional genes and differences were observed between male and female fat bodies in the expression of RPS2, RPL37A and MREL. These findings provide abundant data on the effect of high temperature on insects at the molecular level. The data will also be beneficial to the study of differences between the sexes, manifested in variations in gene expression under high temperature.

Effect of prewarming on the body temperature of small dogs undergoing inhalation anesthesia.

PubMed

Rigotti, Clara F; Jolliffe, Colette T; Leece, Elizabeth A

2015-10-01

To investigate whether prewarming affects body temperature of small dogs (weighing < 10 kg [22 lb]) undergoing inhalation anesthesia. Prospective, randomized, blinded clinical trial. Animals: 20 dogs weighing < 10 kg with American Society of Anesthesiologists physical status I or II. Baseline rectal temperature was recorded. Before IM administration of buprenorphine hydrochloride and acepromazine maleate, dogs were randomly assigned to be placed in a pediatric incubator at 33°C (91.4°F) for approximately 30 to 60 minutes (prewarming group) or to receive no prewarming (control group); subsequently, dogs underwent inhalation anesthesia with isoflurane in oxygen. Rectal, esophageal, and ambient temperatures were measured every 5 minutes from induction of anesthesia (IOA) for > 1 hour by an observer who was unaware of treatment. If a dog became hypothermic (esophageal temperature < 36°C [96.8°F]), it was withdrawn from the study. Variables of interest relating to dogs, anesthesia, temperatures, hypothermia, and study withdrawal were compared between groups. 1 dog was excluded from the prewarming group after becoming excessively excited in the incubator. Between groups, age, weight, body condition score, degree of preanesthesia sedation, interval from sedation to IOA, duration of anesthesia, baseline rectal temperature, rectal temperatures immediately prior to IOA, esophageal temperature following IOA, ambient temperature during the first 70 minutes of anesthesia, esophageal or rectal temperature during the first 90 minutes of anesthesia, and incidence of hypothermia and study withdrawal (5 dogs/group) did not differ significantly. Prewarming in an incubator prior to IOA failed to improve or maintain body temperature of dogs weighing < 10 kg during inhalation anesthesia.

Low body temperature does not compromise the treatment effect of alteplase.

PubMed

Lees, Jennifer S; Mishra, Nishant K; Saini, Monica; Lyden, Patrick D; Shuaib, Ashfaq

2011-09-01

Hypothermia is neuroprotective in ischemic stroke models. The influence of baseline body temperature on outcomes after thrombolytic therapy is unclear. We examined outcomes after alteplase treatment across baseline body temperature for patients with ischemic stroke in data held within the Virtual International Stroke Trials Archive (VISTA; 1998 to 2007). We collated data on age, baseline severity (National Institutes of Health Stroke Scale), and 90-day modified Rankin Scale score on patients presenting with acute ischemic stroke. We compared 90-day modified Rankin Scale score between thrombolyzed and nonthrombolyzed comparators across baseline body temperature. We report age and baseline National Institutes of Health Stroke Scale-adjusted Cochran-Mantel-Haenszel probability value and proportional OR with 95% CI for improved modified Rankin Scale distribution. We report temperature profiles over 72 hours after stroke by treatment group. Rankin data were available for 5586 patients with acute ischemic stroke in VISTA (1980 received alteplase). Age and baseline severity were similar (age 68.0±13.0 years versus 69.9±12.3 years, National Institutes of Health Stroke Scale 14.2±5.2 versus 13.0±5.6). Alteplase was associated with improved outcome (OR, 1.49; 95% CI, 1.35 to 1.65, P<0.0001). Alteplase treatment effect was not associated with baseline temperature (P=0.14). Point estimates showed benefit of alteplase treatment across 35.5°C to 37.5°C but showed a negative trend >37.5°C. Alteplase did not influence temperature profiles over 72 hours after stroke. There is no evidence of influence of body temperature on alteplase treatment response. These results are reassuring that low temperatures across a physiological range do not compromise therapeutic effect of alteplase.

Method for solving the problem of nonlinear heating a cylindrical body with unknown initial temperature

NASA Astrophysics Data System (ADS)

Yaparova, N.

2017-10-01

We consider the problem of heating a cylindrical body with an internal thermal source when the main characteristics of the material such as specific heat, thermal conductivity and material density depend on the temperature at each point of the body. We can control the surface temperature and the heat flow from the surface inside the cylinder, but it is impossible to measure the temperature on axis and the initial temperature in the entire body. This problem is associated with the temperature measurement challenge and appears in non-destructive testing, in thermal monitoring of heat treatment and technical diagnostics of operating equipment. The mathematical model of heating is represented as nonlinear parabolic PDE with the unknown initial condition. In this problem, both the Dirichlet and Neumann boundary conditions are given and it is required to calculate the temperature values at the internal points of the body. To solve this problem, we propose the numerical method based on using of finite-difference equations and a regularization technique. The computational scheme involves solving the problem at each spatial step. As a result, we obtain the temperature function at each internal point of the cylinder beginning from the surface down to the axis. The application of the regularization technique ensures the stability of the scheme and allows us to significantly simplify the computational procedure. We investigate the stability of the computational scheme and prove the dependence of the stability on the discretization steps and error level of the measurement results. To obtain the experimental temperature error estimates, computational experiments were carried out. The computational results are consistent with the theoretical error estimates and confirm the efficiency and reliability of the proposed computational scheme.

Effects of a glyphosate-based herbicide on the development of Common toads (Bufo bufo L.; Amphibia) at different temperatures

NASA Astrophysics Data System (ADS)

Baier, Fabian; Gruber, Edith; Spangl, Bernhard; Zaller, Johann G.

2016-04-01

Herbicides based on the active ingredient glyphosate are frequently applied in agriculture, horticulture and private gardens all over the world. Recently, leaching of glyphosate or its metabolite (AMPA) into water bodies inhabited by amphibians has been reported. However, very little is known about non-target effects of these herbicides on amphibians and even less is known to what extent different temperatures might alter these effects. Using climate chambers, we investigated the effects of the glyphosate-based herbicide Roundup PowerFlex® (480 g L-1 glyphosate, formulated as 588 g L-1 potassium salt) on the larval development of Common toads (Bufo bufo L.; Amphibia: Anura) under different temperature regimes (15°C vs. 20°C). We established five herbicide concentrations: 0, 1.5, 3, 4 mg acid equivalent L-1 and a 4 mg a.e. L-1 pulse treatment (totally three applications of 1.5, 1.5 and another 1 mg a.e. L-1) at each temperature in a full-factorial design. Each treatment combination was replicated five times, the experiment ran for 24 days. Results showed a highly significant effect of temperature on body length and body width but no effect of herbicide concentration on these growth parameters. Moreover, highly significant interactions between herbicide and temperature on body length and body width were observed suggesting that herbicides had different effects on different temperatures. In conclusion, although Roundup PowerFlex® at the tested concentrations appeared to have no acute toxicity to larvae of Common toads, the observed effects on tadpole morphology will potentially affect competitive interactions in spawning ponds of amphibia. Our findings of herbicide x temperature interactions might become more prevalent when human-induced climate change will lead to more extreme temperatures.

The relationship between radiant heat, air temperature and thermal comfort at rest and exercise.

PubMed

Guéritée, Julien; Tipton, Michael J

2015-02-01

The aims of the present work were to investigate the relationships between radiant heat load, air velocity and body temperatures with or without coincidental exercise to determine the physiological mechanisms that drive thermal comfort and thermoregulatory behaviour. Seven male volunteers wearing swimming trunks in 18°C, 22°C or 26°C air were exposed to increasing air velocities up to 3 m s(-1) and self-adjusted the intensity of the direct radiant heat received on the front of the body to just maintain overall thermal comfort, at rest or when cycling (60 W, 60 rpm). During the 30 min of the experiments, skin and rectal temperatures were continuously recorded. We hypothesized that mean body temperature should be maintained stable and the intensity of the radiant heat and the mean skin temperatures would be lower when cycling. In all conditions, mean body temperature was lower when facing winds of 3 m s(-1) than during the first 5 min, without wind. When facing winds, in all but the 26°C air, the radiant heat was statistically higher at rest than when exercising. In 26°C air mean skin temperature was lower at rest than when exercising. No other significant difference was observed. In all air temperatures, high correlation coefficients were observed between the air velocity and the radiant heat load. Other factors that we did not measure may have contributed to the constant overall thermal comfort status despite dropping mean skin and body temperatures. It is suggested that the allowance to behaviourally adjust the thermal environment increases the tolerance of cold discomfort. Copyright © 2014 Elsevier Inc. All rights reserved.

Behavioral buffering of global warming in a cold-adapted lizard.

PubMed

Ortega, Zaida; Mencía, Abraham; Pérez-Mellado, Valentín

2016-07-01

Alpine lizards living in restricted areas might be particularly sensitive to climate change. We studied thermal biology of Iberolacerta cyreni in high mountains of central Spain. Our results suggest that I. cyreni is a cold-adapted thermal specialist and an effective thermoregulator. Among ectotherms, thermal specialists are more threatened by global warming than generalists. Alpine lizards have no chance to disperse to new suitable habitats. In addition, physiological plasticity is unlikely to keep pace with the expected rates of environmental warming. Thus, lizards might rely on their behavior in order to deal with ongoing climate warming. Plasticity of thermoregulatory behavior has been proposed to buffer the rise of environmental temperatures. Therefore, we studied the change in body and environmental temperatures, as well as their relationships, for I. cyreni between the 1980s and 2012. Air temperatures have increased more than 3.5°C and substrate temperatures have increased by 6°C in the habitat of I. cyreni over the last 25 years. However, body temperatures of lizards have increased less than 2°C in the same period, and the linear relationship between body and environmental temperatures remains similar. These results show that alpine lizards are buffering the potential impact of the increase in their environmental temperatures, most probably by means of their behavior. Body temperatures of I. cyreni are still cold enough to avoid any drop in fitness. Nonetheless, if warming continues, behavioral buffering might eventually become useless, as it would imply spending too much time in shelter, losing feeding, and mating opportunities. Eventually, if body temperature exceeds the thermal optimum in the near future, fitness would decrease abruptly.

Metabolic heat production and thermal conductance are mass-independent adaptations to thermal environment in birds and mammals

PubMed Central

Fristoe, Trevor S.; Burger, Joseph R.; Balk, Meghan A.; Khaliq, Imran; Hof, Christian; Brown, James H.

2015-01-01

The extent to which different kinds of organisms have adapted to environmental temperature regimes is central to understanding how they respond to climate change. The Scholander–Irving (S-I) model of heat transfer lays the foundation for explaining how endothermic birds and mammals maintain their high, relatively constant body temperatures in the face of wide variation in environmental temperature. The S-I model shows how body temperature is regulated by balancing the rates of heat production and heat loss. Both rates scale with body size, suggesting that larger animals should be better adapted to cold environments than smaller animals, and vice versa. However, the global distributions of ∼9,000 species of terrestrial birds and mammals show that the entire range of body sizes occurs in nearly all climatic regimes. Using physiological and environmental temperature data for 211 bird and 178 mammal species, we test for mass-independent adaptive changes in two key parameters of the S-I model: basal metabolic rate (BMR) and thermal conductance. We derive an axis of thermal adaptation that is independent of body size, extends the S-I model, and highlights interactions among physiological and morphological traits that allow endotherms to persist in a wide range of temperatures. Our macrophysiological and macroecological analyses support our predictions that shifts in BMR and thermal conductance confer important adaptations to environmental temperature in both birds and mammals. PMID:26668359

Disruption of the circadian period of body temperature by the anesthetic propofol.

PubMed

Touitou, Yvan; Mauvieux, Benoit; Reinberg, Alain; Dispersyn, Garance

2016-01-01

The circadian time structure of an organism can be desynchronized in a large number of instances, including the intake of specific drugs. We have previously found that propofol, which is a general anesthetic, induces a desynchronization of the circadian time structure in rats, with a 60-80 min significant phase advance of body temperature circadian rhythm. We thus deemed it worthwhile to examine whether this phase shift of body temperature was related to a modification of the circadian period Tau. Propofol was administered at three different Zeitgeber Times (ZTs): ZT6 (middle of the rest period), ZT10 (2 h prior to the beginning of activity period), ZT16 (4 h after the beginning of the activity period), with ZT0 being the beginning of the rest period (light onset) and ZT12 being the beginning of the activity period (light offset). Control rats (n = 20) were injected at the same ZTs with 10% intralipid, which is a control lipidic solution. Whereas no modification of the circadian period of body temperature was observed in the control rats, propofol administration resulted in a significant shortening of the period by 96 and 180 min at ZT6 and ZT10, respectively. By contrast, the period was significantly lengthened by 90 min at ZT16. We also found differences in the time it took for the rats to readjust their body temperature to the original 24-h rhythm. At ZT16, the speed of readjustment was more rapid than at the two other ZTs that we investigated. This study hence shows (i) the disruptive effects of the anesthetic propofol on the body temperature circadian rhythm, and it points out that (ii) the period Tau for body temperature responds to this anesthetic drug according to a Tau-response curve. By sustaining postoperative sleep-wake disorders, the disruptive effects of propofol on circadian time structure might have important implications for the use of this drug in humans.

Effect of antiperspirants on whole body sweat rate and thermoregulation.

PubMed

Burry, J S; Evans, R L; Rawlings, A V; Shiu, J

2003-08-01

It is well established that the evaporation of sweat from the human body surface is the main mechanism by which heat balance is maintained following a rise in body core temperature. Since the introduction of the first brand name antiperspirant in the United States during the early 1900s, antiperspirant products designed to control underarm wetness have grown to represent one of the largest cosmetic categories in most global markets. However, although axillary sweating only constitutes less than 1% of whole body sweat rate, consumers, particularly in hot countries, have begun to articulate the concern that antiperspirants may interfere with the body's natural cooling process. To investigate this, we undertook carefully designed experiments that measured the effects of axillary antiperspirant application on whole body sweat rate and body core temperature, following a regimen of exercise-induced heat stress in a hot environment in human volunteers. Our data show clearly that although antiperspirant prevents sweat production in the axillary area, this does not impact the ability of the body to thermoregulate following a rise in body core temperature. Thus, recent consumer questioning over this aspect of antiperspirant use appears to be unwarranted.

Electronic clinical predictive thermometer using logarithm for temperature prediction

NASA Technical Reports Server (NTRS)

Cambridge, Vivien J. (Inventor); Koger, Thomas L. (Inventor); Nail, William L. (Inventor); Diaz, Patrick (Inventor)

1998-01-01

A thermometer that rapidly predicts body temperature based on the temperature signals received from a temperature sensing probe when it comes into contact with the body. The logarithms of the differences between the temperature signals in a selected time frame are determined. A line is fit through the logarithms and the slope of the line is used as a system time constant in predicting the final temperature of the body. The time constant in conjunction with predetermined additional constants are used to compute the predicted temperature. Data quality in the time frame is monitored and if unacceptable, a different time frame of temperature signals is selected for use in prediction. The processor switches to a monitor mode if data quality over a limited number of time frames is unacceptable. Determining the start time on which the measurement time frame for prediction is based is performed by summing the second derivatives of temperature signals over time frames. When the sum of second derivatives in a particular time frame exceeds a threshold, the start time is established.

Reliability of an infrared forehead skin thermometer for core temperature measurements.

PubMed

Kistemaker, J A; Den Hartog, E A; Daanen, H A M

2006-01-01

The SensorTouch thermometer performs an infrared measurement of the skin temperature above the Superficial Temporal Artery (STA). This study evaluates the validity and the accuracy of the SensorTouch thermometer. Two experiments were performed in which the body temperature was measured with a rectal sensor, with an oesophageal sensor and with the SensorTouch. After entering a warm chamber the SensorTouch underestimated the core temperature during the first 10 minutes. After that, the SensorTouch was not significantly different from the core temperature, with an average difference of 0.5 degrees C (SD 0.5 degrees C) in the first study and 0.3 degrees C (SD 0.2 degrees C) in the second study. The largest differences between the SensorTouch and the core temperature existed 15 minutes after the start of the exercise. During this period the SensorTouch was significantly higher than the core temperature. The SensorTouch did not provide reliable values of the body temperature during periods of increasing body temperature, but the SensorTouch might work under stable conditions.

Fabrication of highly dense SiN4 ceramics without additives by high pressure sintering

NASA Technical Reports Server (NTRS)

Takatori, K.; Shimade, M.; Koizumi, M.

1984-01-01

Silicon nitride (Si3N4) is one of candidate materials for the engineering ceramics which is used at high temperatures. The mechanical strengths of hot pressed or sintered Si2N4 ceramics containing some amount of additives, however, are deteriorated at elevated temperatures. To improve the high temperature strength of Si3N4 ceramics, an attempt to consolidate Si3N4 without additives was made by high pressure sintering technique. Scanning electron micrographs of fracture surfaces of the sintered bodies showed the bodies had finely grained and fully self-bonded sintered bodies were 310N sq m at room temperature and 174N/sq m at 1200 C.

Optical Johnson noise thermometry

DOEpatents

Shepard, Robert L.; Blalock, Theron V.; Roberts, Michael J.; Maxey, Lonnie C.

1992-01-01

Method and device for direct, non-contact temperature measure of a body. A laser beam is reflected from the surface of the body and detected along with the Planck radiation. The detected signal is analyzed using signal correlation technique to generate an output signal proportional to the Johnson noise introduced into the reflected laser beam as a direct measure of the absolute temperature of the body.

Primate body temperature and sleep responses to lower body positive pressure

NASA Technical Reports Server (NTRS)

Edgar, D. M.; Fuller, C. A.

1984-01-01

Cephalic fluid shifts, induced by lower body positive pressure (LBPP) are known to influence various physiological systems (i.e., cardiovascular and renal). In earlier experiments, an apparent change in the arousal state of primates in such LBPP conditions was observed. This study was designed to examine the effects of LBPP on arousal state and body temperature level which is normally correlated with sleep. Chair-restrained male squirrel monkeys were exposed to 40 mmHg LBPP for 90-100 minutes between the daytime hours of 13:00-15:00. Each monkey was placed in a specially modified restraint chair to which they were highly trained. Deep body temperature (DBT) was collected from 10 animals. Sleep parameters were obtained from six animals chronically implanted for sleep recording. A video camera was used to observe each animal's apparent state of arousal. LBPP resulted in an approximate 0.9 C decrease in DBT. During video observation, some animals appeared drowsy during LBPP; however, sleep recording revealed no significant changes in the state of arousal. Thus, LBPP is capable of inducing a mild hyperthermia. Further, the mechanisms underlying the observed lowering of body temperature appear to be independent of arousal state.

Overwintering strategy of wild free-ranging and enclosure-housed Japanese raccoon dogs ( Nyctereutes procyonoides albus)

NASA Astrophysics Data System (ADS)

Kitao, Naoya; Fukui, Daisuke; Hashimoto, Masaaki; Osborne, Peter G.

2009-03-01

The raccoon dog, Nyctereutes procyonoides, is a canid with a passive overwintering strategy in northern Europe. However, the behaviour and physiology of the Japanese subspecies, N. p. albus, which has fewer chromosomes than the other subspecies, remain unknown. We measured body temperature, body composition and blood biochemistry of wild free-ranging and fasted enclosure-housed N. p. albus during boreal winter in Hokkaido, Japan. Body temperature of N. p. albus decreased from 38°C in autumn to 35.9-36.7°C while maintaining a circadian rhythm in late February ( n = 3). A transient 18-36% decrease in resting heart rate occurred when body temperature was low ( n = 2). Despite a 33-45% decrease in body weight due to winter fasting, circulating glucose, total protein and triglyceride levels were maintained ( n = 4). Serum urea nitrogen dropped by 43-45% from autumn to spring, suggesting protein conservation during fasting. The overwintering survival strategy of N. p. albus in central Hokkaido is based upon large changes in seasonal activity patterns, winter denning and communal housing without the large decrease in body temperature that is characteristic of subarctic animals exhibiting hibernation or torpor.

Impacts of exhalation flow on the microenvironment around the human body under different room temperatures

NASA Astrophysics Data System (ADS)

Jafari, Mohammad Javad; Gharari, Noradin; Azari, Mansour Rezazade; Ashrafi, Khosro

2018-04-01

Exhalation flow and room temperature can have a considerable effect on the microenvironment in the vicinity of human body. In this study, impacts of exhalation flow and room temperature on the microenvironment around a human body were investigated using a numerical simulation. For this purpose, a computational fluid dynamic program was applied to study thermal plume around a sitting human body at different room temperatures of a calm indoor room by considering the exhalation flow. The simulation was supported by some experimental measurements. Six different room temperatures (18 to 28 °C) with two nose exhalation modes (exhalation and non-exhalation) were investigated. Overhead and breathing zone velocities and temperatures were simulated in different scenarios. This study finds out that the exhalation through the nose has a significant impact on both quantitative and qualitative features of the human microenvironment in different room temperatures. At a given temperature, the exhalation through the nose can change the location and size of maximum velocity at the top of the head. In the breathing zone, the effect of exhalation through the nose on velocity and temperature distribution was pronounced for the point close to mouth. Also, the exhalation through the nose strongly influences the thermal boundary layer on the breathing zone while it only minimally influences the convective boundary layer on the breathing zone. Overall results demonstrate that it is important to take the exhalation flow into consideration in all areas, especially at a quiescent flow condition with low temperature.

Electromagnetic field triggered drug and chemical delivery via liposomes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liburdy, R.P.

1993-03-02

The present invention relates to a system and to a method of delivering a drug to a preselected target body site of a patient, comprising the steps of encapsulating the chemical agent within liposomes, essentially temperature insensitive, i.e. not having a specific predetermined phase transition temperature within the specific temperature range of drug administration; administering the liposomes to the target body site; and subjecting the target body site to nonionizing electromagnetic fields in an area of the preselected target body in order to release the chemical agent from the liposomes at a temperature of between about +10 and 65 C.more » The invention further relates to the use of the liposomes to bind to the surface of or to enter target tissue or an organ in a living system, and, when subjected to a nonionizing field, to release a drug from the liposomes into the target site.« less

Electromagnetic field triggered drug and chemical delivery via liposomes

DOEpatents

Liburdy, R.P.

1993-03-02

The present invention relates to a system and to a method of delivering a drug to a preselected target body site of a patient, comprising the steps of encapsulating the chemical agent within liposomes, essentially temperature insensitive, i.e. not having a specific predetermined phase transition temperature within the specific temperature range of drug administration; administering the liposomes to the target body site; and subjecting the target body site to nonionizing electromagnetic fields in an area of the preselected target body in order to release the chemical agent from the liposomes at a temperature of between about +10 and 65 C. The invention further relates to the use of the liposomes to bind to the surface of or to enter target tissue or an organ in a living system, and, when subjected to a nonionizing field, to release a drug from the liposomes into the target site.

Electromagnetic field triggered drug and chemical delivery via liposomes

DOEpatents

Liburdy, Robert P.

1993-01-01

The present invention relates to a system and to a method of delivering a drug to a preselected target body site of a patient, comprising the steps of encapsulating the chemical agent within liposomes, essentially temperature insensitive, i.e. not having a specific predetermined phase transition temperature within the specific temperature range of drug administration; administering the liposomes to the target body site; and subjecting the target body site to nonionizing electromagnetic fields in an area of the preselected target body in order to release said chemical agent from the liposomes at a temperature of between about +10 and 65.degree. C. The invention further relates to the use of said liposomes to bind to the surface of or to enter target tissue or an organ in a living system, and, when subjected to a nonionizing field, to release a drug from the liposomes into the target site.

A study on the measurement of the core body temperature change after radiofrequency ablation (RFA) through MR temperature mapping

NASA Astrophysics Data System (ADS)

Kim, Chang-Bok; Dong, Kyung-Rae; Yu, Young; Chung, Woon-Kwan; Cho, Jae-Hwan; Joo, Kyu-Ji

2013-09-01

This study examined the change in the heat generated during radiofrequency ablation (RFA) using a self-manufactured phantom and used magnetic resonance imaging (MRI) to analyze the change in the temperature of the core body and the tissues surrounding the phantom. In this experiment, the image and the phase image were obtained simultaneously from a gradient echo-based sequence using 1.5-Tesla MRI equipment and a 12-channel head coil. The temperature mapping technique was used to calculate the change in temperature. The regions of interest (ROIs) (ROI 1 - ROI 6) were set with a focus on the area where the RFA was performed, according to the temperature distribution, before monitoring the temperature change for one hour in time intervals of five minutes. The results showed that the temperature change in the ROI with time was largest in the ROI 1 and smallest in the ROI 5. In addition, after the RFA procedure, the temperature decreased from the initial value to 0 °C in one hour. The temperature changes in the core body and the surrounding tissues were confirmed by MRI temperature mapping, which is a noninvasive method.

Effects of temperature on the metabolic response to feeding in Python molurus.

PubMed

Wang, Tobias; Zaar, Morten; Arvedsen, Sine; Vedel-Smith, Christina; Overgaard, Johannes

2002-11-01

As ectothermic vertebrates, reptiles undergo diurnal and seasonal changes in body temperature, which affect many biological functions. In conjunction with a general review regarding the effects of temperature on digestion in reptiles, we describe the effects of various temperatures (20-35 degrees C) on the metabolic response to digestion in the Burmese python (Python molurus). The snakes were fed mice amounting to 20% of their body weight and gas exchange (oxygen uptake and CO(2) production) were measured until digestion had ended and gas exchange returned to fasting levels. Elevated temperature was associated with a faster and larger metabolic increase after ingestion, and the time required to return to fasting levels was markedly longer at low temperature. The factorial increase between fasting oxygen consumption (VO(2)) and maximal VO(2) during digestion was, however, similar at all temperatures studied. Furthermore, the integrated SDA response was not affected by temperature suggesting the costs associated with digestion are temperature-independent. Other studies on reptiles show that digestive efficiency is only marginally affected by temperature and we conclude that selection of higher body temperatures during digestion (postprandial thermophilic response) primarily reduces the time required for digestion.

Climatic influences on human body size and proportions: ecological adaptations and secular trends.

PubMed

Katzmarzyk, P T; Leonard, W R

1998-08-01

This study reevaluates the long-standing observation that human morphology varies with climate. Data on body mass, the body mass index [BMI; mass (kg)/stature (m)2], the surface area/body mass ratio, and relative sitting height (RSH; sitting height/stature) were obtained for 223 male samples and 195 female samples derived from studies published since D.F. Roberts' landmark paper "Body weight, race, and climate" in 1953 (Am. J. Phys. Anthropol. 11:533-558). Current analyses indicate that body mass varies inversely with mean annual temperature in males (r=-0.27, P < 0.001) and females (r=-0.28, P < 0.001), as does the BMI (males: r=-0.22, P=0.001; females: r=-0.30, P < 0.001). The surface area/body mass ratio is positively correlated with temperature in both sexes (males: r=0.29, P < 0.001; females: r=0.34, P < 0.001), whereas the relationship between RSH and temperature is negative (males: r=-0.37, P < 0.001; females: r=-0.46, P < 0.001). These results are consistent with previous work showing that humans follow the ecological rules of Bergmann and Allen. However, the slope of the best-fit regressions between measures of body mass (i.e., mass, BMI, and surface area/mass) and temperature are more modest than those presented by Roberts. These differences appear to be attributable to secular trends in mass, particularly among tropical populations. Body mass and the BMI have increased over the last 40 years, whereas the surface area/body mass ratio has decreased. These findings indicate that, although climatic factors continue to be significant correlates of world-wide variation in human body size and morphology, differential changes in nutrition among tropical, developing world populations have moderated their influence.

Contribution of garment fit and style to thermal comfort at the lower body.

PubMed

Mert, Emel; Böhnisch, Sonja; Psikuta, Agnes; Bueno, Marie-Ange; Rossi, René M

2016-12-01

The heat and mass transfer between the human body and the environment is not only affected by the properties of the fabric, but also by the size of the air gap thickness and the magnitude of the contact area between the body and garment. In this clothing-human-environment system, there is also an interaction between the clothing and the physiological response of the wearer. Therefore, the aim of this study was to evaluate the distribution of the air gap thickness and the contact area for the male lower body in relation to the garment fit and style using a three-dimensional (3D) body scanning method with a manikin. Moreover, their relation with the physiological response of the lower body was analysed using the physiological modelling. The presented study showed that the change in the air gap thickness and the contact area due to garment fit was greater for legs than the pelvis area due to regional differences of the body. Furthermore, the garment style did not have any effect on the core temperature or total water loss of the lower body, whereas the effect of garment fit on the core temperature and total water loss of lower body was observed only for 40 °C of ambient temperature. The skin temperatures were higher for especially loose garments at thigh than the tight garments. Consequently, the results of this study indicated that the comfort level of the human body for a given purpose can be adjusted by selection of fabric type and the design of ease allowances in the garment depending on the body region.

A systematic review of randomised controlled trials of the effects of warmed irrigation fluid on core body temperature during endoscopic surgeries.

PubMed

Jin, Yinghui; Tian, Jinhui; Sun, Mei; Yang, Kehu

2011-02-01

The purpose of this systematic review was to establish whether warmed irrigation fluid temperature could decrease the drop of body temperature and incidence of shivering and hypothermia. Irrigation fluid, which is used in large quantities during endoscopic surgeries at room temperature, is considered to be associated with hypothermia and shivering. It remains controversial whether using warmed irrigation fluid to replace room-temperature irrigation fluid will decrease the drop of core body temperature and the occurrence of hypothermia. A comprehensive search (computerised database searches, footnote chasing, citation chasing) was undertaken to identify all the randomised controlled trials that explored temperature of irrigation fluid in endoscopic surgery. An approach involving meta-analysis was used. We searched PubMed, EMBASE, Cochrane Library, SCI, China academic journals full-text databases, Chinese Biomedical Literature Database, Chinese scientific journals databases and Chinese Medical Association Journals for trials that meet the inclusion criteria. Study quality was assessed using standards recommended by Cochrane Library Handbook 5.0.1. Disagreement was resolved by consensus. Thirteen randomised controlled trials including 686 patients were identified. The results showed that room-temperature irrigation fluid caused a greater drop of core body temperature in patients, compared to warmed irrigation fluid (p < 0.00001; I(2) = 85%). The occurrence of shivering [odds ratio (OR) 5.13, 95% CI: 2.95-10.19, p < 0.00001; I(2) = 0%] and hypothermia (OR 22.01, 95% CI: 2.03-197.08, p = 0.01; I(2) = 64%) in the groups having warmed irrigation fluid were lower than the group of studies having room-temperature fluid. In endoscopic surgeries, irrigation fluid is recommended to be warmed to decrease the drop of core body temperature and the risk of perioperative shivering and hypothermia. Warming irrigating fluid should be considered standard practice in all endoscopic surgeries. © 2011 Blackwell Publishing Ltd.

Use of thermal imagery for estimation of core body temperature during precooling, exertion, and recovery in wildland firefighter protective clothing.

PubMed

Bourlai, Thirimachos; Pryor, Riana R; Suyama, Joe; Reis, Steven E; Hostler, David

2012-01-01

Monitoring core body temperature to identify heat stress in first responders and in individuals participating in mass gatherings (e.g., marathons) is difficult. This study utilized high-sensitivity thermal imaging technology to predict the core temperature of human subjects at a distance while performing simulated field operations wearing thermal protective garments. Six male subjects participating in a study of precooling prior to exertion in wildland firefighter thermal protective clothing had thermal images of the face captured with a high-resolution thermal imaging camera concomitant with measures of core and skin temperature before, during, and after treadmill exercise in a heated room. Correlations and measures of agreement between core temperature and thermal imaging-based temperature were performed. The subjects walked an average (± standard deviation) of 42.6 (±5.9) minutes and a distance of 4.2 (±0.6) km on the treadmill. Mean heart rate at the end of exercise was 152 (±33) bpm and core body temperature at the end of exercise was 38.3°C (±0.7°C). A visual relationship and a strong correlation between core temperature and thermal imaging of the face were identified in all subjects, with the closest relationship and best agreement occurring during exercise. The Bland-Altman test of agreement during exercise revealed the majority of measurement pairs to be within two standard deviations of the measured temperature. High-resolution thermal imaging in the middle-wave infrared spectrum (3-5 μm) can be used to accurately estimate core body temperature during exertion in a hot room while participants are wearing wildland firefighting garments. Although this technology is promising, it must be refined. Using alternative measurement sites such as the skin over the carotid artery, using multiple measurement sites, or adding pulse detection may improve the estimation of body temperature by thermal imagery.

A Proposed Methodology to Control Body Temperature in Patients at Risk of Hypothermia by means of Active Rewarming Systems

PubMed Central

Costanzo, Silvia; Cusumano, Alessia; Giaconia, Carlo; Mazzacane, Sante

2014-01-01

Hypothermia is a common complication in patients undergoing surgery under general anesthesia. It has been noted that, during the first hour of surgery, the patient's internal temperature (T core) decreases by 0.5–1.5°C due to the vasodilatory effect of anesthetic gases, which affect the body's thermoregulatory system by inhibiting vasoconstriction. Thus a continuous check on patient temperature must be carried out. The currently most used methods to avoid hypothermia are based on passive systems (such as blankets reducing body heat loss) and on active ones (thermal blankets, electric or hot-water mattresses, forced hot air, warming lamps, etc.). Within a broader research upon the environmental conditions, pollution, heat stress, and hypothermia risk in operating theatres, the authors set up an experimental investigation by using a warming blanket chosen from several types on sale. Their aim was to identify times and ways the human body reacts to the heat flowing from the blanket and the blanket's effect on the average temperature T skin and, as a consequence, on T core temperature of the patient. The here proposed methodology could allow surgeons to fix in advance the thermal power to supply through a warming blanket for reaching, in a prescribed time, the desired body temperature starting from a given state of hypothermia. PMID:25485278

Changing body temperature affects the T2* signal in the rat brain and reveals hypothalamic activity.

PubMed

Vanhoutte, G; Verhoye, M; Van der Linden, A

2006-05-01

This study was designed to determine brain activity in the hypothalamus-in particular the thermoregulatory function of the hypothalamic preoptic area (PO). We experimentally changed the body temperature in rats within the physiological range (37-39 degrees C) and monitored changes in blood oxygenation level-dependent (BOLD) MR signal. To explore PO activity we had to deal with general signal changes caused by temperature-dependent alterations in the affinity of oxygen for hemoglobin, which contributes to BOLD contrast because it is partly sensitive to the amount of paramagnetic deoxyhemoglobin in the voxel. To reduce these overall temperature-induced effects, we corrected the BOLD data using brain-specific correction algorithms. The results showed activity of the PO during body warming from 38 degrees C to 39 degrees C, supported by an increased BOLD signal after correction. This is the first fMRI study on the autonomous nervous system in which hypothalamic activity elicited by changes in the internal environment (body temperature) was monitored. In this study we also demonstrate 1) that any fMRI study of anesthetized small animals should guard against background BOLD signal drift, since animals are vulnerable to body temperature fluctuations; and 2) the existence of a link between PO activity and the sympathetically-mediated opening of the arteriovenous anastomoses in a parallel study on the rat tail, a peripheral thermoregulatory organ.

Possibility of passive THz camera using for a temperature difference observing of objects placed inside the human body

NASA Astrophysics Data System (ADS)

Trofimov, Vyacheslav A.; Trofimov, Vladislav V.; Kuchik, Igor E.

2014-06-01

As it is well-known, application of the passive THz camera for the security problems is very promising way. It allows seeing concealed object without contact with a person and this camera is non-dangerous for a person. We demonstrate new possibility of the passive THz camera using for a temperature difference observing on the human skin if this difference is caused by different temperatures inside the body. We discuss some physical experiments, in which a person drinks hot, and warm, and cold water and he eats. After computer processing of images captured by passive THz camera TS4 we may see the pronounced temperature trace on skin of the human body. For proof of validity of our statement we make the similar physical experiment using the IR camera. Our investigation allows to increase field of the passive THz camera using for the detection of objects concealed in the human body because the difference in temperature between object and parts of human body will be reflected on the human skin. However, modern passive THz cameras have not enough resolution in a temperature to see this difference. That is why, we use computer processing to enhance the camera resolution for this application. We consider images produced by THz passive cameras manufactured by Microsemi Corp., and ThruVision Corp.

Heterothermy in large mammals: inevitable or implemented?

PubMed

Hetem, Robyn S; Maloney, Shane K; Fuller, Andrea; Mitchell, Duncan

2016-02-01

Advances in biologging techniques over the past 20 years have allowed for the remote and continuous measurement of body temperatures in free-living mammals. While there is an abundance of literature on heterothermy in small mammals, fewer studies have investigated the daily variability of body core temperature in larger mammals. Here we review measures of heterothermy and the factors that influence heterothermy in large mammals in their natural habitats, focussing on large mammalian herbivores. The mean 24 h body core temperatures for 17 species of large mammalian herbivores (>10 kg) decreased by ∼1.3°C for each 10-fold increase in body mass, a relationship that remained significant following phylogenetic correction. The degree of heterothermy, as measured by the 24 h amplitude of body core temperature rhythm, was independent of body mass and appeared to be driven primarily by energy and water limitations. When faced with the competing demands of osmoregulation, energy acquisition and water or energy use for thermoregulation, large mammalian herbivores appear to relax the precision of thermoregulation thereby conserving body water and energy. Such relaxation may entail a cost in that an animal moves closer to its thermal limits for performance. Maintaining homeostasis requires trade-offs between regulated systems, and homeothermy apparently is not accorded the highest priority; large mammals are able to maintain optimal homeothermy only if they are well nourished, hydrated, and not compromised energetically. We propose that the amplitude of the 24 h rhythm of body core temperature provides a useful index of any compromise experienced by a free-living large mammal and may predict the performance and fitness of an animal. © 2014 Cambridge Philosophical Society.

METHOD FOR FORMING A COATING OF MOLYBDENUM CARBIDE ON A CARBON BODY

DOEpatents

Simnad, M.T.

1962-04-01

A method is described for coating a carbon bodywith molybdenum carbide in such a manner that the carbon body is rendered less permeable to the flow of gases and has increased resistance to corrosion and erosion. The method includes coating a carbon body with molybdenum trioxide by contacting it at a temperature below the condensation temperature with molybdenum trioxide vapors and thereafter carburizing the molybdenum trioxide in situ in an inert atmosphere on the carhon body. (AEC)

Cooling Different Body Surfaces during Upper-and-Lower Body Exercise.

DTIC Science & Technology

1986-09-01

exercise (02 uptake, 1.2 lmin -) tests in a hot environment. (ambient temperature - 38*C, relative humidity - 30%) while dressed in a clothing ... exercise (02 uptake, 1.2 l’min-) t,sts in a hot environment (ambient temperature a 380C, relative humidity = 30%) while , - dressed in a clothing ...AD-A173 328 COOLING DIFFERENT BODY SURFACES DURING UPPER-AND-LONEi 1i/I BODY EXERCISE (U) ARMY RESEARCH INST OF ENYVIONMENTAL MEDICINE NATICK MR A J

Circadian variation in the effects of nitric oxide synthase inhibitors on body temperature, feeding and activity in rats.

PubMed

Kamerman, Peter; Mitchell, Duncan; Laburn, Helen

2002-02-01

We have investigated whether there is circadian variation in the effects of nitric oxide synthase inhibitors on body temperature, physical activity and feeding. We used nocturnally active Sprague-Dawley rats, housed at approximately 24 degrees C with a 12:12 h light:dark cycle (lights on 07:00 hours) and provided with food and water ad libitum. Nitric oxide synthesis was inhibited by intraperitoneal injection of the unspecific nitric oxide synthase inhibitor N-nitro- L-arginine methyl ester ( L-NAME, 100, 50, 25, 10 mg/kg), or the relatively selective inducible nitric oxide synthase inhibitor aminoguanidine (100, 50 mg/kg), during the day ( approximately 09:00 hours) or night ( approximately 21:00 hours). Body temperature and physical activity were measured using radiotelemetry, while food intake was calculated by weighing each animal's food before as well as 12 and 24 h after each injection. We found that daytime injection of L-NAME and aminoguanidine had no effect on daytime body temperature. However, daytime injection of both drugs did decrease nocturnal food intake ( P<0.05) and activity ( P<0.05). When injected at night, L-NAME reduced night-time body temperature ( P<0.01), activity ( P<0.05) and food intake ( P<0.05) in a dose-dependent manner, but night-time injection of aminoguanidine inhibited only night-time activity ( P<0.05). The effects of nitric oxide synthase inhibition on body temperature, feeding and activity therefore are primarily a consequence of inhibiting constitutively expressed nitric oxide synthase, and are subject to circadian variation.

Body temperature, thermoregulatory behaviour and pelt characteristics of three colour morphs of springbok (Antidorcas marsupialis).

PubMed

Hetem, Robyn S; de Witt, Brenda A; Fick, Linda G; Fuller, Andrea; Kerley, Graham I H; Meyer, Leith C R; Mitchell, Duncan; Maloney, Shane K

2009-03-01

Using intra-abdominal miniature data loggers, we measured core body temperature in female springbok (Antidorcas marsupialis) of three colour morphs (black, normal and white), free-living in the Karoo, South Africa, for one year. During winter, white springbok displayed lower daily minimum body temperatures (37.4+/-0.5 degrees C), than both black (38.1+/-0.3 degrees C) and normal (38.0+/-0.6 degrees C) springbok. During spring, black springbok displayed higher daily maximum body temperatures (40.7+/-0.1 degrees C) than both white (40.2+/-0.2 degrees C) and normal (40.2+/-0.2 degrees C) springbok. These high maximum body temperatures were associated with larger daily amplitudes of nychthemeral rhythm of body temperature (2.0+/-0.2 degrees C), than that of white (1.6+/-0.1 degrees C) and normal (1.7+/-0.2 degrees C) springbok. Biophysical properties of sample springbok pelts were consistent with these patterns, as the black springbok pelt showed lower reflectance in the visible spectral range, and higher heat load from simulated solar radiation, than did the pelts of the other two springbok. Black springbok had lower diurnal activity in winter, consistent with them having to forage less because their metabolic cost of homeothermy was lower, but were disadvantaged in hot periods. White springbok, by contrast, were more protected from solar heat load, but potentially less able to meet the energy cost of homeothermy in winter. Thus energy considerations may underlie the rarity of the springbok colour morphs.

18F-FDG uptake in the colon is modulated by metformin but not associated with core body temperature and energy expenditure.

PubMed

Bahler, Lonneke; Holleman, Frits; Chan, Man-Wai; Booij, Jan; Hoekstra, Joost B; Verberne, Hein J

2017-01-01

Physiological colonic 18F-fluorodeoxyglucose (18F-FDG) uptake is a frequent finding on 18F-FDG positron emission tomography computed tomography (PET-CT). Interestingly, metformin, a glucose lowering drug associated with moderate weight loss, is also associated with an increased colonic 18F-FDG uptake. Consequently, increased colonic glucose use might partly explain the weight losing effect of metformin when this results in an increased energy expenditure and/or core body temperature. Therefore, we aimed to determine whether metformin modifies the metabolic activity of the colon by increasing glucose uptake. In this open label, non-randomized, prospective mechanistic study, we included eight lean and eight overweight males. We measured colonic 18F-FDG uptake on PET-CT, energy expenditure and core body temperature before and after the use of metformin. The maximal colonic 18F-FDG uptake was measured in 5 separate segments (caecum, colon ascendens,-transversum,-descendens and sigmoid). The maximal colonic 18F-FDG uptake increased significantly in all separate segments after the use of metformin. There was no significant difference in energy expenditure or core body temperature after the use of metformin. There was no correlation between maximal colonic 18F-FDG uptake and energy expenditure or core body temperature. Metformin significantly increases colonic 18F-FDG uptake, but this increased uptake is not associated with an increase in energy expenditure or core body temperature. Although the colon might be an important site of the glucose plasma lowering actions of metformin, this mechanism of action does not explain directly any associated weight loss.

Sex Hormones, Sleep, and Core Body Temperature in Older Postmenopausal Women

PubMed Central

Murphy, Patricia J.; Campbell, Scott S.

2007-01-01

Study Objectives: Assessment of relationships between polysomnographic sleep, sex hormones, and core body temperature in postmenopausal women. Design and Participants: Ten women aged 57 to 71 years, at least 5 years past menopause. Setting: Laboratory of Human Chronobiology at Weill Cornell Medical College. Interventions: N/A. Measurements and Results: Lower estradiol (E2) and higher luteinizing hormone (LH) levels were significantly correlated with indices of poor sleep quality. Relationships between LH and polysomnographic variables were more robust than those for E2. Significant increases from basal LH levels (i.e., LH pulses) occurred more frequently after sleep onset than prior to sleep onset, and 30 of 32 of these LH pulses occurred prior to long awakenings from sleep. In addition, higher body core temperature prior to and during sleep was significantly correlated with poorer sleep efficiency and higher LH levels. Conclusions: Most investigations of relationships between sleep, sex hormones, and body temperature have focused on perimenopausal women, menopausal phenomena such as hot flashes, the role of declining estrogen, and treatment with exogenous estrogen. The current results suggest that altered levels of both sex steroids and gonadotropins may contribute to sleep disturbance in older women and confirm the results of previous studies indicating that higher body core temperature is associated with poorer sleep quality, even in women without vasomotor symptoms. The findings also raise the possibility of alternate treatment avenues for menopause- and age-related sleep disturbance that focus on altering LH levels. Citation: Murphy PJ; Campbell SS. Sex hormones, sleep, and core body temperature in older postmenopausal women. SLEEP 2007;30(12):1788-1794. PMID:18246988

Placement of temperature probe in bovine vagina for continuous measurement of core-body temperature.

PubMed

Lee, C N; Gebremedhin, K G; Parkhurst, A; Hillman, P E

2015-09-01

There has been increasing interest to measure core-body temperature in cattle using internal probes. This study examined the placement of HOBO water temperature probe with an anchor, referred to as the "sensor pack" (Hillman et al. Appl Eng Agric ASAE 25(2):291-296, 2009) in the vagina of multiparous Holstein cows under grazing conditions. Two types of anchors were used: (a) long "fingers" (4.5-6 cm), and (b) short "fingers" (3.5 cm). The long-finger anchors stayed in one position while the short-finger anchors were not stable in one position (rotate) within the vagina canal and in some cases came out. Vaginal temperatures were recorded every minute and the data collected were then analyzed using exponential mixed model regression for non-linear data. The results showed that the core-body temperatures for the short-finger anchors were lower than the long-finger anchors. This implied that the placement of the temperature sensor within the vagina cavity may affect the data collected.

Placement of temperature probe in bovine vagina for continuous measurement of core-body temperature

NASA Astrophysics Data System (ADS)

Lee, C. N.; Gebremedhin, K. G.; Parkhurst, A.; Hillman, P. E.

2015-09-01

There has been increasing interest to measure core-body temperature in cattle using internal probes. This study examined the placement of HOBO water temperature probe with an anchor, referred to as the "sensor pack" (Hillman et al. Appl Eng Agric ASAE 25(2):291-296, 2009) in the vagina of multiparous Holstein cows under grazing conditions. Two types of anchors were used: (a) long "fingers" (4.5-6 cm), and (b) short "fingers" (3.5 cm). The long-finger anchors stayed in one position while the short-finger anchors were not stable in one position (rotate) within the vagina canal and in some cases came out. Vaginal temperatures were recorded every minute and the data collected were then analyzed using exponential mixed model regression for non-linear data. The results showed that the core-body temperatures for the short-finger anchors were lower than the long-finger anchors. This implied that the placement of the temperature sensor within the vagina cavity may affect the data collected.

Human thermoregulation and measurement of body temperature in exercise and clinical settings.

PubMed

Lim, Chin Leong; Byrne, Chris; Lee, Jason Kw

2008-04-01

This review discusses human thermoregulation during exercise and the measurement of body temperature in clinical and exercise settings. The thermoregulatory mechanisms play important roles in maintaining physiological homeostasis during rest and physical exercise. Physical exertion poses a challenge to thermoregulation by causing a substantial increase in metabolic heat production. However, within a non-thermolytic range, the thermoregulatory mechanisms are capable of adapting to sustain physiological functions under these conditions. The central nervous system may also rely on hyperthermia to protect the body from "overheating." Hyperthermia may serve as a self-limiting signal that triggers central inhibition of exercise performance when a temperature threshold is achieved. Exposure to sub-lethal heat stress may also confer tolerance against higher doses of heat stress by inducing the production of heat shock proteins, which protect cells against the thermolytic effects of heat. Advances in body temperature measurement also contribute to research in thermoregulation. Current evidence supports the use of oral temperature measurement in the clinical setting, although it may not be as convenient as tympanic temperature measurement using the infrared temperature scanner. Rectal and oesophagus temperatures are widely accepted surrogate measurements of core temperature (Tc), but they cause discomfort and are less likely to be accepted by users. Gastrointestinal temperature measurement using the ingestible temperature sensor provides an acceptable level of accuracy as a surrogate measure of Tc without causing discomfort to the user. This form of Tc measurement also allows Tc to be measured continuously in the field and has gained wider acceptance in the last decade.

Interleukin-1β and interleukin-6 enhance thermal prolongation of the LCR in decerebrate piglets.

PubMed

Xia, Luxi; Bartlett, Donald; Leiter, J C

2016-08-01

Thermal stress and prior upper respiratory tract infection are risk factors for the Sudden Infant Death Syndrome. The adverse effects of prior infection are likely mediated by interleukin-1β (IL-1β). Therefore, we examined the single and combined effects of IL-1β and elevated body temperature on the duration of the Laryngeal Chemoreflex (LCR) in decerebrate neonatal piglets ranging in age from post-natal day (P) 3 to P7. We examined the effects of intraperitoneal (I.P.) injections of 0.3mg/Kg IL-1β with or without I.P. 10mg/Kg indomethacin pretreatment on the duration of the LCR, and in the same animals we also examined the duration of the LCR when body temperature was elevated approximately 2°C. We found that IL-1β significantly increased the duration of the LCR even when body temperature was held constant. There was a significant multiplicative effect when elevated body temperature was combined with IL-1β treatment: prolongation of the LCR was significantly greater than the sum of independent thermal and IL-1β-induced prolongations of the LCR. The effects of IL-1β, but not elevated body temperature, were blocked by pretreatment with indomethacin alone. We also tested the interaction between IL-6 given directly into the nucleus of the solitary tract (NTS) bilaterally in 100ngm microinjections of 50μL and pretreatment with indomethacin. Here again, there was a multiplicative effect of IL-6 treatment and elevated body temperature, which significantly prolonged the LCR. The effect of IL-6 on the LCR, but not elevated body temperature, was blocked by pretreatment with indomethacin. We conclude that cytokines interact with elevated body temperature, probably through direct thermal effects on TRPV1 receptors expressed pre-synaptically in the NTS and through cytokine-dependent sensitization of the TRPV1 receptor. This sensitization is likely initiated by cyclo-oxygenase-2 dependent synthesis of prostaglandin E2, which is stimulated by elevated levels of IL-1β or IL-6. Inflammatory sensitization of the LCR coupled with thermal prolongation of the LCR may increase the propensity for apnea and Sudden Infant Death Syndrome. Copyright © 2016 Elsevier B.V. All rights reserved.

Interleukin-1β and interleukin-6 enhance thermal prolongation of the LCR in decerebrate piglets

PubMed Central

Xia, Luxi; Bartlett, Donald; Leiter, J.C.

2017-01-01

Thermal stress and prior upper respiratory tract infection are risk factors for the Sudden Infant Death Syndrome. The adverse effects of prior infection are likely mediated by interleukin-1β (IL-1β). Therefore, we examined the single and combined effects of IL-1β and elevated body temperature on the duration of the Laryngeal Chemoreflex (LCR) in decerebrate neonatal piglets ranging in age from post-natal day (P) 3 to P7. We examined the effects of intraperitoneal (I.P.) injections of 0.3 mg/Kg IL-1β with or without I.P. 10 mg/Kg indomethacin pretreatment on the duration of the LCR, and in the same animals we also examined the duration of the LCR when body temperature was elevated approximately 2 °C. We found that IL-1β significantly increased the duration of the LCR even when body temperature was held constant. There was a significant multiplicative effect when elevated body temperature was combined with IL-1β treatment: prolongation of the LCR was significantly greater than the sum of independent thermal and IL-1β-induced prolongations of the LCR. The effects of IL-1β, but not elevated body temperature, were blocked by pretreatment with indomethacin alone. We also tested the interaction between IL-6 given directly into the nucleus of the solitary tract (NTS) bilaterally in 100 ngm microinjections of 50 μL and pre-treatment with indomethacin. Here again, there was a multiplicative effect of IL-6 treatment and elevated body temperature, which significantly prolonged the LCR. The effect of IL-6 on the LCR, but not elevated body temperature, was blocked by pretreatment with indomethacin. We conclude that cytokines interact with elevated body temperature, probably through direct thermal effects on TRPV1 receptors expressed pre-synaptically in the NTS and through cytokine-dependent sensitization of the TRPV1 receptor. This sensitization is likely initiated by cyclo-oxygenase-2 dependent synthesis of prostaglandin E2, which is stimulated by elevated levels of IL-1β or IL-6. Inflammatory sensitization of the LCR coupled with thermal prolongation of the LCR may increase the propensity for apnea and Sudden Infant Death Syndrome. PMID:27181326

Regional blood flow in sea turtles: implications for heat exchange in an aquatic ectotherm.

PubMed

Hochscheid, Sandra; Bentivegna, Flegra; Speakman, John R

2002-01-01

Despite substantial knowledge on thermoregulation in reptiles, the mechanisms involved in heat exchange of sea turtles have not been investigated in detail. We studied blood flow in the front flippers of two green turtles, Chelonia mydas, and four loggerhead turtles, Caretta caretta, using Doppler ultrasound to assess the importance of regional blood flow in temperature regulation. Mean blood flow velocity and heart rate were determined for the water temperature at which the turtles were acclimated (19.3 degrees-22.5 degrees C) and for several experimental water temperatures (17 degrees-32 degrees C) to which the turtles were exposed for a short time. Flipper circulation increased with increasing water temperature, whereas during cooling, flipper circulation was greatly reduced. Heart rate was also positively correlated with water temperature; however, there were large variations between individual heart rate responses. Body temperatures, which were additionally determined for the two green turtles and six loggerhead turtles, increased faster during heating than during cooling. Heating rates were positively correlated with the difference between acclimation and experimental temperature and negatively correlated with body mass. Our data suggest that by varying circulation of the front flippers, turtles are capable of either transporting heat quickly into the body or retaining heat inside the body, depending on the prevailing thermal demands.

The role of fluid temperature and form on endurance performance in the heat.

PubMed

Tan, P M S; Lee, J K W

2015-06-01

Exercising in the heat often results in an excessive increase in body core temperature, which can be detrimental to health and endurance performance. Research in recent years has shifted toward the optimum temperature at which drinks should be ingested. The ingestion of cold drinks can reduce body core temperature before exercise but less so during exercise. Temperature of drinks does not seem to have an effect on the rate of gastric emptying and intestinal absorption. Manipulating the specific heat capacity of a solution can further induce a greater heat sink. Ingestion of ice slurry exploits the additional energy required to convert the solution from ice to water (enthalpy of fusion). Body core temperature is occasionally observed to be higher at the point of exhaustion with the ingestion of ice slurry. There is growing evidence to suggest that ingesting ice slurry is an effective and practical strategy to prevent excessive rise of body core temperature and improve endurance performance. This information is especially important when only a fixed amount of fluid is allowed to be carried, often seen in some ultra-endurance events and military operations. Future studies should evaluate the efficacy of ice slurry in various exercise and environmental conditions. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.