scholarly journals Temperature Gradient Evolution (∆t) and Glycaemia as Complementary Parameters for Diagnosis and Treatment Monitoring of Glucose Metabolism Disorders

2021 ◽  
Vol 1 (3) ◽  
Author(s):  
Coulic V
Keyword(s):  
Body Temperature ◽  
Glucose Metabolism ◽  
Temperature Gradient ◽  
Ambient Temperature ◽  
Wistar Rats ◽  
Surgical Stress ◽  
Glucose Metabolism Disorders ◽  
Insulin Administration ◽  
Body Temperatures ◽  
Slight Elevation

Background: Anaesthesia and surgical interventions cause significant changes in body temperature and glycaemia control in human and in animals. Different measures were successfully applied to counter these changes. On the other hand, the treatment of acute or chronic glucose metabolism disorders based only on the evolution of serum glucose is not entirely satisfactory, using a device (ADD/) to measure the evolution of core/ deep and surface body temperatures and their difference (∆t), we investigated the relation between ∆t and glycaemia during anaesthesia in healthy and diabetic animals (rats) and during surgical operations in humans. Therefore, we followed the spontaneous evolution of glycaemia and body temperatures during anaesthesia and surgical stress, with or without interventions (insulin and glucose perfusion) to verify/justify the possibility of the intervention monitoring following ∆t evolution. Methods: Fifty two Wistar rats were used, 26 as controls and 26 with an experimental diabetes induced with streptozotocin to investigate the effect of anaesthesia and surgical stress alone. Another group of 26 Wistar rats were used in the same conditions plus insulin and glucose intravenous injection. The experiments were conducted in standard conditions of room temperature. After anaesthetics administration glycaemia was measured every 15-30min. Deep and superficial temperatures and their difference ΔT were registered continuously using an ADD device. Results: In intact anaesthetized animals after a slight elevation during the first 30 minutes, glycaemia decreased regularly with time during anaesthesia body temperature gradient (∆t) absolute values depended on the position of the temperature sensors and on ambient temperature, but their evolution was the same: slight initial decrease, stabilization and slight elevation before waking. Correlation between the two parameters was not evident. Thoracic surgery caused a more pronounced temperature decrease and glycaemia changes than anaesthesia alone (∆t not measured). In diabetic animals, as a rule glycaemia remained high during the operation time, the variations of ∆t values were more important and prolonged, as a rule ∆t was lower in diabetic animals than in healthy ones. Correlation with glycaemia could not be detected. Comparison between investigation results in animals before and after diabetes induction has pointed the important differences due to the disease and confirmed that ∆t reactions always preceded glycaemia ones) that explain the absence of correlation between these parameters). In all the series anaesthetic overdose could cause a temporary negative ∆t even in presence of normo- or hyperglycaemia. Ambient temperature elevation >30°C during the sessions caused an increase of all investigated features absolute values but none of their evolution. Taking into account the quick reaction of ∆t to modifications of external and internal conditions, monitoring glycaemia disorders by balanced insulin and glucose intravenous injection guided by ∆t evolution was tried with positive encouraging results. Clinical observations were added which results were close to the experimental ones, as well when concerning the influence of external (temperature) and internal (anaesthesia), metabolic factors, as when confirm possibility of monitoring insulin administration with energetic feedback. Conclusion: This study confirms that stress, ambient temperature and anaesthesia can alter both glycaemia and body temperature evolution, and that more profoundly in diabetes. It has shown a high sensibility of ∆t to the metabolic changes due to these factors. It ought to allow a valuable algorithm elaboration for glucose and insulin administration in automatic monitoring of energetic balance by a new ADD-CIGT device.

Body temperature regulation and oxygen consumption in young chicks fed thyroid hormone

1991 ◽  
Vol 69 (7) ◽  
pp. 1842-1847 ◽  
Author(s):  
Gregory K. Snyder ◽  
Joseph R. Coelho ◽  
Dalan R. Jensen
Keyword(s):  
Oxygen Consumption ◽  
Thyroid Hormone ◽  
Body Temperature ◽  
Ambient Temperature ◽  
Cold Exposure ◽  
Elevated Serum ◽  
Body Temperatures ◽  
Serum Thyroid Hormone ◽  
Regulate Body Temperature ◽  
Young Chicks

In chicks the ability to regulate body temperature to adult levels develops during the first 2 weeks of life. We examined whether the ability of young chicks to regulate body temperature is increased by elevated levels of the thyroid hormone 3,3′5-triiodothyronine. By 13 days following hatch, body temperatures of chicks were not significantly different from those expected for adult birds. Furthermore, at an ambient temperature of 10 °C, 13-day-old control chicks were able to maintain body temperature, and elevated serum thyroid hormone levels did not increase rates of oxygen consumption or body temperature above control values. Six-day-old chicks had body temperatures that were significantly lower than those of the 13-day-old chicks and were not able to regulate body temperature when exposed to an ambient temperature of 10 °C. On the other hand, 6-day-old chicks with elevated serum thyroid hormone had significantly higher rates of oxygen consumption than 6-day-old control chicks, and were able to maintain constant body temperatures during cold exposure. The increased oxygen consumption rates and improved ability to regulate body temperature during cold exposure were correlated with increased citrate synthase activity in skeletal muscle. Our results support the argument that thyroid hormones play an important role in the development of thermoregulatory ability in neonate birds by stimulating enzyme activities associated with aerobic metabolism.

scholarly journals Body Temperatures in Some Australian Mammals II.Peramelidae

1962 ◽  
Vol 15 (2) ◽  
pp. 386 ◽  
Author(s):  
PR Morrison
Keyword(s):  
Body Temperature ◽  
Ambient Temperature ◽  
Active Phase ◽  
Temperature Measurements ◽  
Temperature Cycle ◽  
Body Temperatures ◽  
Ambient Temperatures ◽  
Diurnal Temperature

Body temperature measurements on the short-nosed bandicoot (Thylacis obeaulus) have shown a nocturnal cycle with a range of 1� 2�C and a short active phase at 2200-0400 hr. The bilby or rabbit bandicoot (Macrotis lagoti8) had a sharply defined temperature cycle, with a range of almost 3�C after several months of captivity, during which the day-time resting temperature was progressively lowered from 36� 4 to 34� 2�C. Forced activity raised the diurnal temperature substantially but not to the nocturnal level. Forced activity did not raise the nocturnal level which was similar in the two species (37' O�C). Both species could regulate effectively at an ambient temperature of 5�C, but only Thylaci8 showed regulation at ambient temperatures of between 30 and 40�C.

Thermal homeostasis in rats after intrahypothalamic injections of 6-hyroxydopamine

1976 ◽  
Vol 230 (4) ◽  
pp. 932-939 ◽  
Author(s):  
JG Van Zoeren ◽  
EM Stricker
Keyword(s):  
Body Temperature ◽  
Ambient Temperature ◽  
Thermal Balance ◽  
Local Injection ◽  
Noradrenergic Neurons ◽  
Body Temperatures ◽  
Hypothalamic Region ◽  
Electrolytic Lesions ◽  
Noradrenergic Fibers ◽  
Effector Mechanisms

Specific destruction of at least 90% of the noradrenergic neurons in the preoptic/anterior hypothalamic region (PO/AH) by local injection of 9-hyroxydopamine (6-HDA) did not disrupt thermoregulation by rats either in the heat or the cold. Examination of the multiple effector mechanisms suggested that thermal balance was maintained in a normal fashion, and that compensatory adjustments did not conceal individual dysfunctions. In contrast with the ineffectual 6-HDA lesions of the PO/AH were the outstanding impairments seen in rats following electrolytic lesions of this area. All the latter animals became severely hyperthermic during the 1st h of exposure to an ambient temperature of 40 degrees C, and half of them were additionally unable to maintain body temperatures when exposed to an ambient temperature of 6 degrees C. The electrolytic lesions reduced norepinephrine levels in the PO/AH, but the 50-70% depletions were substantially smaller than those found in 6-HDA-treated rats. These results raise new doubts about whether central noradrenergic fibers have an important role in the regulation of body temperature by rats.

Studies on the adaptability of three breeds of sheep to a tropical environment modified by altitude II. Responses in body, skin and coat temperatures, cardio-respiratory frequencies and rate of moisture secretion of ewes to the diurnal fluctuation in ambient temperature during the hottest part of the year

1960 ◽  
Vol 55 (3) ◽  
pp. 295-302 ◽  
Author(s):  
R. B. Symington
Keyword(s):  
Body Temperature ◽  
Ambient Temperature ◽  
Skin Temperature ◽  
Skin Surface ◽  
Diurnal Fluctuation ◽  
Body Temperatures ◽  
Solar Insolation ◽  
Air Temperatures ◽  
Insensible Perspiration ◽  
Artificial Heat

Responses in body, skin and coat temperatures, cardio-respiratory frequencies and rate of moisture secretion of ewes of three breeds to the diurnal fluctuation in ambient temperature were recorded in the presence and absence of drinking water during the hottest part of the Rhodesian year.1. At 7.0 a.m. body temperatures were: Merino 102·8° F.; Persian 102·2° F. and Native 101·5° F. Between 7·0 a.m. and 1·0 p.m. body temperature rose almost equally in Persians and Natives and fell slightly in Merinos. Change in body temperature between 7.0 a.m. and 1.0 p.m. was not affected significantly by availability of water nor age of ewe, but varied with type of thermal burden (i.e. solar insolation only v. solar insolation plus artificial heat) when water was not available. Although air temperature fell towards late afternoon body temperature of Merinos and Natives rose appreciably, that of Persians only slightly.2. At 7·0 a.m. respiratory rates were (cyc./min.): Merino 59·6; Persian 43·0; Native 29·9. Increase in rate of respiration was the main thermolytic mechanism in all breeds. Merinos had a lower threshold of respiratory response to rising ambient temperature than either hair breed but increase in rate of respiration between 7.0 a.m. and 1.0 p.m. did not differ significantly with breed or age.3. No breed appeared to use the peripheral blood system in thermoregulation. Cardio-frequency, as a measure of this blood flow, remained almost constant with a slight tendency to fall with rise in ambient temperature.4. In all breeds skin temperature was related to ambient and body temperatures; consequently the diurnal fluctuation in skin temperature differed in wool and hair breeds. When thermal burden was greatest Merino skin temperature fell, that of hair breeds did not.Except at 11.0 a.m. there was a gradient between rectal, skin and air temperatures. Direct elimination of heat was thus possible for 23 hr. each day.5. In hair breeds moisture secretion depended on insensible perspiration; consequently, rate of moisture secretion changed with body and air temperatures. In Merinos moisture for skin surface evaporation was provided by sensible and insensible perspiration. Natives may be able to sweat at temperatures higher than those recorded but it is unlikely Persians have a sweating mechanism.6. In all breeds coat temperature was related closely to ambient temperature and changes in solar conditions evoked immediate response in coat temperature. Merino fleece apparently stabilized skin temperature whereas Persian and Native hair did not.

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

2017 ◽  
Vol 4 (12) ◽  
pp. 171359 ◽  
Author(s):  
M. Teague O'Mara ◽  
Sebastian Rikker ◽  
Martin Wikelski ◽  
Andries Ter Maat ◽  
Henry S. Pollock ◽  
...  
Keyword(s):  
Heart Rate ◽  
Body Temperature ◽  
Metabolic Rate ◽  
Ambient Temperature ◽  
The Body ◽  
Metabolic Rates ◽  
Body Temperatures ◽  
Wide Range ◽  
Save Energy ◽  
Molossus Molossus

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.

scholarly journals Thermal biology of Amphisbaena munoai (Squamata: Amphisbaenidae)

2018 ◽  
Vol 35 ◽  
pp. 1-9 ◽  
Author(s):  
Nathalia Rocha Matias ◽  
Laura Verrastro
Keyword(s):  
Body Temperature ◽  
Ambient Temperature ◽  
Thermal Environment ◽  
Rio Grande ◽  
The Body ◽  
Rio Grande Do Sul ◽  
Body Temperatures ◽  
Physiological Mechanisms ◽  
Thermal Biology ◽  
The Relationship

Studies on the thermal biology of fossorial reptiles that examine the relationship between the body temperature and thermal environment are needed to determine the extent of their thermoregulation abilities. This study assessed the thermal biology of Amphisbaena munoai Klappenbach, 1969 in the rocky fields of the Rio Grande do Sul and in the laboratory. The body temperature of most individuals was between 24 and 30 °C, both in the field (n = 81) and laboratory (n = 19). More individuals were caught in winter (n = 55) and spring (n = 60) than in summer (n = 25) and fall (n = 45), and in spring, individuals showed similar nocturnal and diurnal activities. In the laboratory, we found individuals with body temperatures up to 5 °C higher than the ambient temperature (n = 4), suggesting that some physiological mechanisms participate in the thermoregulation of these animals. Amphisbaena munoai is a thigmothermic species that is capable of actively regulating its temperature by selecting microhabitats such that its various activities occur within an ideal temperature range. This study is the first to evaluate the effect of seasonality and diurnal and nocturnal variations on the thermoregulation of an amphisbaenid.

Differential effects of hypoxia on sleep of warm- and cold-acclimated rats

1987 ◽  
Vol 63 (6) ◽  
pp. 2189-2194 ◽  
Author(s):  
M. J. Pollard ◽  
D. Megirian ◽  
J. H. Sherrey
Keyword(s):  
Body Temperature ◽  
Ambient Temperature ◽  
Neural Mechanism ◽  
Body Temperatures ◽  
Deep Body Temperature ◽  
Neutral Temperature ◽  
State Changes ◽  
Different Levels ◽  
Deep Body ◽  
Maximum Minimum

We studied the effect of different levels of hypoxia (10, 12 or 13, 15, and 18% O2) on the sleep-waking pattern (SWP) and the maximum-minimum core temperature of warm-acclimated (WA) and cold-acclimated (CA) rats at their neutral temperature, 29 degrees C. Whereas the SWP of WA rats showed a trend toward increasing disruption as the degree of hypoxia increased, CA rats exhibited no such trend. The effect was chiefly on the frequency of state changes and less on epoch durations. The SWP of WA rats was more vulnerable to hypoxia than that of CA rats. Maximum and minimum body temperatures of WA and CA rats were not significantly affected by O2 lack down to 10% inspired O2. We conclude that in the rat 1) hypoxia primarily affects the neural mechanism that governs the frequency of changes in sleep-waking states; 2) the extent of alterations in SWP's depends on the ambient temperature to which the rats are acclimated; and 3) hypoxia does not significantly affect deep body temperature at the animal's neutral temperature.

scholarly journals ENDOTHERMY AND TEMPERATURE REGULATION IN BEES: A CRITIQUE OF ‘GRAB AND STAB’ MEASUREMENT OF BODY TEMPERATURE

1989 ◽  
Vol 143 (1) ◽  
pp. 211-223 ◽  
Author(s):  
G. N. STONE ◽  
P. G. WILLMER
Keyword(s):  
Body Temperature ◽  
Ambient Temperature ◽  
Laboratory Experiments ◽  
Passive Cooling ◽  
Time Interval ◽  
Body Temperatures ◽  
Warm Up ◽  
Tethered Flight ◽  
The Relationship ◽  
Best Fit

‘Grab and stab’ methods have become standard in the measurement of insect body temperatures. The gradient of the best-fit regression of body temperature on ambient temperature is often used as a measure of the thermoregulatory ability of a species. The temperatures recorded are commonly accepted as slight underestimates of actual values prior to capture due to passive cooling between capture and insertion of the thermocouple. Here we present laboratory experiments involving tethered flight which show that bees often warm up on cessation of flight, and that errors due to warm-up over the time interval typically associated with ‘grab and stab’ sampling may be significant. More importantly, the errors due to warm-up in two species are shown to change with ambient temperature, thus affecting the form of the relationship between ambient and body temperatures. We compare laboratory and field data to illustrate the way in which warm-up errors may exaggerate apparent thermoregulatory ability, and we urge greater caution in the interpretation of ‘grab and stab’ data.

Fetal and maternal body temperatures measured by radiotelemetry in near-term sheep during thermal stress

1992 ◽  
Vol 72 (3) ◽  
pp. 894-900 ◽  
Author(s):  
H. P. Laburn ◽  
D. Mitchell ◽  
K. Goelst
Keyword(s):  
Thermal Stress ◽  
Body Temperature ◽  
Temperature Gradient ◽  
Thermal Injury ◽  
Exposure Period ◽  
Body Temperatures ◽  
Initial Exposure ◽  
Mild Heat ◽  
Near Term ◽  
Pregnant Ewe

Using implanted radiotelemeters, we have measured amniotic temperature and fetal lamb and pregnant ewe body temperatures continuously over the last 34 days of gestation and during conditions of thermal stress. Body temperature of the fetus was approximately 0.6 degrees C higher than that of the mother, and the fetomaternal temperature difference remained constant over the last 25 days of gestation, until the immediate prepartum period, when it rose. During exposure to mild heat stress (35 degrees C dry-bulb temperature, 24 degrees C wet-bulb temperature), ewe and fetal body temperatures rose, but fetal temperature rose at a slower rate. Thus the fetomaternal temperature gradient fell significantly in the initial exposure period. In an environment of 4 degrees C, body temperature of the pregnant ewes fell, but the fetomaternal gradient did not change significantly. During maternal fever, heat loss from the fetus was compromised; body temperature of the fetus rose more than that of the mother, and the fetomaternal temperature gradient rose significantly. We suggest that mild heat or cold exposure in pregnant animals constitutes little risk of fetal thermal stress. During maternal fever, however, the fetus may be at risk of thermal injury.

Comparative effects of hypoxia on behavioral thermoregulation in rats, hamsters, and mice

1991 ◽  
Vol 260 (1) ◽  
pp. R120-R125 ◽  
Author(s):  
C. J. Gordon ◽  
L. Fogelson
Keyword(s):  
Statistical Analysis ◽  
Body Temperature ◽  
Temperature Gradient ◽  
Sample Size ◽  
Oxygen Content ◽  
Rodent Species ◽  
Behavioral Thermoregulation ◽  
Body Temperatures ◽  
Set Point ◽  
Deep Body

Recent studies using reptiles and other ectothermic species have shown that hypoxia lowers the set point for the control of body temperature. This is characterized by a preference for cooler ambient (Ta) and deep body temperatures (Tb) when placed in a temperature gradient. To elucidate the presence of this effect in mammals, the selected Ta and Tb of three rodent species (mouse, hamster, and rat) were measured while subjected to graded hypoxia in a temperature gradient. Individual animals were placed in the gradient for 30 min. Oxygen content of air entering the gradient was then reduced to a constant level for a period of 60 min by dilution with nitrogen. Tb was significantly reduced in all species at %O2 levels of 5.5-10%. Selected Ta was significantly reduced in the mouse at %O2 levels of 5.5 and 7.3%. Selected Ta of the hamster and rat were reduced slightly at %O2 levels of 5.8 and 7.4%, respectively; however, the effect was not statistically significant. To clarify the effects of hypoxia in these two species, the sample size of rat and hamster was increased to strengthen statistical analysis, and the animals were exposed for 60 min to %O2 levels of 7.4 and 6.7%, respectively. Both species exhibited a significant reduction in selected Ta during hypoxia concomitant with hypothermia. These data support the hypothesis that hypoxia lowers the set point for the control of body temperature in rodents.

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