Infrared thermal imaging as a method to study thermogenesis in the neonatal lamb

2014 ◽  
Vol 54 (9) ◽  
pp. 1497 ◽  
Author(s):  
S. A. McCoard ◽  
H. V. Henderson ◽  
F. W. Knol ◽  
S. K. Dowling ◽  
J. R. Webster
Keyword(s):  
Body Temperature ◽  
Heat Loss ◽  
Cold Exposure ◽  
Thermal Imaging ◽  
Core Body Temperature ◽  
Recovery Period ◽  
Exposure Period ◽  
Skin Surface ◽  
Infrared Thermal Imaging ◽  
Core Body

The combination of heat generation and reducing heat loss from the skin surface is important for maintaining core body temperature in a neonate. Thermogenesis studies traditionally focus on measurement of core body temperature but not the contribution of radiated heat loss at the skin surface. This study aimed to evaluate the utility of using thermal imaging to measure radiated heat loss in newborn lambs. Continuous thermal images of newborn lambs were captured for 30 min each during the baseline (11−18°C), cold-exposure (0°C) and recovery (11−18°C) periods by using an infrared camera. Core body temperature measured by rectal thermometer was also recorded at the end of each period. In all, 7 of the 10 lambs evaluated had reduced rectal temperatures (0.4−1°C) between the baseline and recovery periods, while three maintained body temperature despite cold exposure. During the baseline period, infrared heat loss was relatively stable, followed by a rapid decrease of 5°C within 5 min of cold exposure. Heat loss continued to decrease linearly in the cold-exposure period by a further 10°C, but increased rapidly to baseline levels during the recovery period. A temperature change of between 20°C and 35°C was observed during the study, which was likely to be due to changes in vasoconstriction in the skin to conserve heat. The present study has highlighted the sensitivity of infrared thermal imaging to estimate heat loss from the skin in the newborn lamb and shown that rapid changes in heat loss occur in response to cold exposure.

scholarly journals Thermal conditions experienced during differentiation affect metabolic and contractile phenotypes of mouse myotubes

2016 ◽  
Vol 311 (3) ◽  
pp. R457-R465 ◽  
Author(s):  
Alex G. Little ◽  
Frank Seebacher
Keyword(s):  
Body Temperature ◽  
Cold Exposure ◽  
Metabolic Flux ◽  
Core Body Temperature ◽  
Thermal Conditions ◽  
Glycolytic Flux ◽  
Peripheral Tissues ◽  
Atp Production ◽  
Metabolic Role ◽  
Core Body

Central pathways regulate metabolic responses to cold in endotherms to maintain relatively stable internal core body temperatures. However, peripheral muscles routinely experience temperatures lower than core body temperature, so that it would be advantageous for peripheral tissues to respond to temperature changes independently from core body temperature regulation. Early developmental conditions can influence offspring phenotypes, and here we tested whether developing muscle can compensate locally for the effects of cold exposure independently from central regulation. Muscle myotubes originate from undifferentiated myoblasts that are laid down during embryogenesis. We show that in a murine myoblast cell line (C2C12), cold exposure (32°C) increased myoblast metabolic flux compared with 37°C control conditions. Importantly, myotubes that differentiated at 32°C compensated for the thermodynamic effects of low temperature by increasing metabolic rates, ATP production, and glycolytic flux. Myotube responses were also modulated by the temperatures experienced by “parent” myoblasts. Myotubes that differentiated under cold exposure increased activity of the AMP-stimulated protein kinase (AMPK), which may mediate metabolic changes in response cold exposure. Moreover, cold exposure shifted myosin heavy chains from slow to fast, presumably to overcome slower contractile speeds resulting from low temperatures. Adjusting thermal sensitivities locally in peripheral tissues complements central thermoregulation and permits animals to maintain function in cold environments. Muscle also plays a major metabolic role in adults, so that developmental responses to cold are likely to influence energy expenditure later in life.

scholarly journals Elevated body temperature during sleep in orexin knockout mice

2006 ◽  
Vol 291 (3) ◽  
pp. R533-R540 ◽  
Author(s):  
Takatoshi Mochizuki ◽  
Elizabeth B. Klerman ◽  
Takeshi Sakurai ◽  
Thomas E. Scammell
Keyword(s):  
Locomotor Activity ◽  
Body Temperature ◽  
Heat Loss ◽  
Core Body Temperature ◽  
Biological Rhythms ◽  
Physiological Factors ◽  
Sustained Activity ◽  
Recovery Sleep ◽  
Core Body ◽  
Elevated Body Temperature

Core body temperature (Tb) is influenced by many physiological factors, including behavioral state, locomotor activity, and biological rhythms. To determine the relative roles of these factors, we examined Tb in orexin knockout (KO) mice, which have a narcolepsy-like phenotype with severe sleep-wake fragmentation. Because orexin is released during wakefulness and is thought to promote heat production, we hypothesized that orexin KO mice would have lower Tb while awake. Surprisingly, Tb was the same in orexin KO mice and wild-type (WT) littermates during sustained wakefulness. Orexin KO mice had normal diurnal variations in Tb, but the ultradian rhythms of Tb, locomotor activity, and wakefulness were markedly reduced. During the first 15 min of spontaneous sleep, the Tb of WT mice decreased by 1.0°C, but Tb in orexin KO mice decreased only 0.4°C. Even during intense recovery sleep after 8 h of sleep deprivation, the Tb of orexin KO mice remained 0.7°C higher than in WT mice. This blunted fall in Tb during sleep may be due to inadequate activation of heat loss mechanisms or sustained activity in heat-generating systems. These observations reveal an unexpected role for orexin in thermoregulation. In addition, because heat loss is an essential aspect of sleep, the blunted fall in Tb of orexin KO mice may provide an explanation for the fragmented sleep of narcolepsy.

Disturbance of thermal homeostasis following dynamic exercise

2007 ◽  
Vol 32 (4) ◽  
pp. 818-831 ◽  
Author(s):  
Glen P. Kenny ◽  
Ollie Jay ◽  
W. Shane Journeay
Keyword(s):  
Body Temperature ◽  
Heat Loss ◽  
Core Body Temperature ◽  
Dynamic Exercise ◽  
Hemodynamic Changes ◽  
Post Exercise ◽  
Cutaneous Vasodilation ◽  
Baseline Values ◽  
Sudomotor Activity ◽  
Core Body

Recovery from dynamic exercise results in significant perturbations of thermoregulatory control. These perturbations evoke a prolonged elevation in core body temperature and a concomitant decrease in sweating, skin blood flow, and skin temperature to pre-exercise baseline values within the early stages of recovery. Cutaneous vasodilation and sweating are critical responses necessary for effective thermoregulation during heat stress in humans. The ability to modulate the rate of heat loss through adjustments in vasomotor and sudomotor activity is a fundamental mechanism of thermoregulatory homeostasis. There is a growing body of evidence in support of a possible relationship between hemodynamic changes postexercise and heat loss responses. Specifically, nonthermoregulatory factors, such as baroreceptors, associated with hemodynamic changes, influence the regulation of core body temperature during exercise recovery. The following review will examine the etiology of the post-exercise disturbance in thermal homeostasis and evaluate possible thermal and nonthermal factors associated with a prolonged hyperthermic state following exercise.

Circadian rhythms in bed rest: Monitoring core body temperature via heat-flux approach is superior to skin surface temperature

2016 ◽  
Vol 34 (5) ◽  
pp. 666-676 ◽  
Author(s):  
Stefan Mendt ◽  
Martina Anna Maggioni ◽  
Michael Nordine ◽  
Mathias Steinach ◽  
Oliver Opatz ◽  
...  
Keyword(s):  
Heat Flux ◽  
Body Temperature ◽  
Circadian Rhythms ◽  
Surface Temperature ◽  
Core Body Temperature ◽  
Bed Rest ◽  
Skin Surface ◽  
Skin Surface Temperature ◽  
Core Body

scholarly journals Liver Derived FGF21 Maintains Core Body Temperature During Acute Cold Exposure

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Magdalene Ameka ◽  
Kathleen R. Markan ◽  
Donald A. Morgan ◽  
Lucas D. BonDurant ◽  
Sharon O. Idiga ◽  
...  
Keyword(s):  
Body Temperature ◽  
Cold Exposure ◽  
Core Body Temperature ◽  
Acute Cold Exposure ◽  
Core Body

Effects of intermittent cold exposure varying in intensity on core body temperature and resting heat production of beef cattle

2001 ◽  
Vol 81 (4) ◽  
pp. 459-465 ◽  
Author(s):  
R. D. Bergen ◽  
A. D. Kennedy ◽  
R. J. Christopherson
Keyword(s):  
Body Temperature ◽  
Beef Cattle ◽  
Heat Production ◽  
Cold Exposure ◽  
Core Body Temperature ◽  
Daily Maximum ◽  
Adaptation Period ◽  
Temperature Rhythms ◽  
Core Body ◽  
Vaginal Temperature

Crossbred beef heifers (n = 18) fed at 1.3× maintenance were exposed to summer daytime temperatures (20 ± 0.2°C) for 8 h (08:00 until 16:00) and to control (22°C), moderate (–6°C) or cold (–15°C) environments for 16 h daily (16:00 until 08:00) for a minimum 21-d adaptation period to investigate the effects of in tensity of intermittent cold exposure on vaginal temperature and resting heat production. Resting heat production was measured at the end of the adaptation period. Vaginal temperature was continuously monitored throughout the experiment using radiotelemetry. Vaginal temperature increased immediately after the onset of cold exposure in both moderate and cold treatments, peaked after 3 h, and returned to pre-exposure levels by the time the 16-h treatment ended. In contrast, vaginal temperatures of control heifers peaked only after feeding at 08:30. Treatment did not affect daily maximum (P= 0.60), mean (P = 0.72) or minimum (P = 0.34) vaginal temperatures, but heifers in both cold-exposed treatments spent more time (P = 0.03) with vaginal temperatures exceeding the daily mean vaginal temperature than control heifers. Compared to control heifers, the variability of vaginal temperature increased 1.8- and 2.2-fold in the moderate and cold treatments, respectively (P = 0.04), and did not change with time (P = 0.98 ). Resting heat production did not increase following 21 d of exposure to moderate and cold conditions. Results of this study indicate that intermittent cold exposure influenced circadian body temperature rhythms without increasing resting heat production. Key words: Beef cattle, thermoregulation, vaginal temperature, heat production.

scholarly journals Accidental perioperative hypothermia

2020 ◽  
pp. 82-83
Author(s):  
I.E. Sharun ◽  
V.V. Petrov
Keyword(s):  
Body Temperature ◽  
Heat Loss ◽  
Core Body Temperature ◽  
Recovery Period ◽  
Perioperative Period ◽  
Healing Time ◽  
Duration Of Action ◽  
Perioperative Hypothermia ◽  
Period Increase ◽  
Cold Shivering

The problem of perioperative hypothermia is still relevant. There are many reasons for that. One of them: a decrease in the patient’s body temperature during the operation often goes unnoticed, or is not perceived by medical staff as a serious complication. Perioperative unintentional hypothermia is a decrease in the patient’s core body temperature <36 °C in the periods: 1 h before anesthesia, during surgery and 24 h after anesthesia. Usually a decrease in body temperature activates the hypothalamic mechanisms of thermoregulation, which provide first vasoconstriction, which reduces heat loss, and then the development of cold shivering (contractile thermogenesis) – heat production. Modern anesthetics affect the regulation of central temperature and lead to its reduction in the perioperative period. Unintentional intraoperative hypothermia accompanies many surgeries performed under general and regional anesthesia. It is perhaps the most important factor in the “triad of death” (hypovolemia, acidosis, hypothermia), which significantly increases the risk of complications, including: prolongation of the duration of action of anesthetics and muscle relaxants and the recovery period; increase in the volume of intraoperative blood loss; from the cardiovascular system complications up to fatal consequences; development of wound infection, increase in wound healing time; increasing the frequency of cold shivering, nausea and vomiting in the postoperative period. Thus, perioperative hypothermia leads to an increase in hospitalization and nosocomial mortality. An important role in the prevention and relief of perioperative hypothermia is played by the competence and motivation of the nurse to timely and effective action in all areas of the perioperative process using thermometry methods available in a specific medical institution (axillary, esophageal or tympanic), prevention of heat loss through the skin under the influence of the environment (room air temperature, operating and equipment), passive and active (convection systems) heating patients with a body temperature <36 °C, rapid thawing and heating to 37 °C of allogeneic blood components. It is especially important during emergency operations, when it is necessary to start warming and temperature monitoring in the intensive care unit of the admission department.

scholarly journals Influence of Cold-TRP Receptors on Cold-Influenced Behaviour

2021 ◽  
Vol 15 (1) ◽  
pp. 42
Author(s):  
Dibesh Thapa ◽  
Brentton Barrett ◽  
Fulye Argunhan ◽  
Susan D. Brain
Keyword(s):  
Body Temperature ◽  
Cold Exposure ◽  
Transient Receptor Potential ◽  
Trp Channels ◽  
Core Body Temperature ◽  
Physical Restraint ◽  
Receptor Potential ◽  
Whole Body ◽  
Direct Role ◽  
Core Body

The transient receptor potential (TRP) channels, TRPA1 and TRPM8, are thermo-receptors that detect cold and cool temperatures and play pivotal roles in mediating the cold-induced vascular response. In this study, we investigated the role of TRPA1 and TRPM8 in the thermoregulatory behavioural responses to environmental cold exposure by measuring core body temperature and locomotor activity using a telemetry device that was surgically implanted in mice. The core body temperature of mice that were cooled at 4 °C over 3 h was increased and this was accompanied by an increase in UCP-1 and TRPM8 level as detected by Western blot. We then established an effective route, by which the TRP antagonists could be administered orally with palatable food. This avoids the physical restraint of mice, which is crucial as that could influence the behavioural results. Using selective pharmacological antagonists A967079 and AMTB for TRPA1 and TRPM8 receptors, respectively, we show that TRPM8, but not TRPA1, plays a direct role in thermoregulation response to whole body cold exposure in the mouse. Additionally, we provide evidence of increased TRPM8 levels after cold exposure which could be a protective response to increase core body temperature to counter cold.

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