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.

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.

scholarly journals Effects on fetal and maternal body temperatures of exposure of pregnant ewes to heat, cold, and exercise

2002 ◽  
Vol 92 (2) ◽  
pp. 802-808 ◽  
Author(s):  
Helen P. Laburn ◽  
Alida Faurie ◽  
Kathleen Goelst ◽  
Duncan Mitchell
Keyword(s):  
Body Temperature ◽  
Relative Humidity ◽  
Treadmill Exercise ◽  
Thermal Environment ◽  
Heat Exposure ◽  
Body Temperatures ◽  
Maternal Body ◽  
Fetal Lamb ◽  
The Difference ◽  
Pregnant Ewe

We exposed Dorper-cross ewes at ∼120–135 days of gestation to a hot (40°C, 60% relative humidity) and a cold (4°C, 90% relative humidity) environment and to treadmill exercise (2.1 km/h, 5° gradient) and measured fetal lamb and ewe body temperatures using previously implanted abdominal radiotelemeters. When ewes were exposed to 2 h of heat or 30 min of exercise, body temperature rose less in the fetus than in the mother, such that the difference between fetal and maternal body temperature, on average 0.6°C before the thermal stress, fell significantly by 0.54 ± 0.06°C (SE, n = 8) during heat exposure and by 0.21 ± 0.08°C ( n = 7) during exercise. During 6 h of maternal exposure to cold, temperature fell significantly less in the fetus than in the ewe, and the difference between fetal and maternal body temperature rose to 1.16 ± 0.26°C ( n = 9). Thermoregulatory strategies used by the pregnant ewe for thermoregulation during heat or cold exposure appear to protect the fetus from changes in its thermal environment.

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.

Daily Torpor and Thermoregulation in the Small Dasyurid Marsupials Planigale-Gilesi and Ningaui-Yvonneae

1988 ◽  
Vol 36 (4) ◽  
pp. 473 ◽  
Author(s):  
F Geiser ◽  
RV Baudinette
Keyword(s):  
Thermal Stress ◽  
Body Temperature ◽  
Metabolic Rate ◽  
Heat Loss ◽  
Body Mass ◽  
Selective Pressure ◽  
Daily Torpor ◽  
Small Species ◽  
Body Temperatures ◽  
Strong Selective Pressure

Torpor in endotherms has only been observed in small species, suggesting that body mass determines the occurrence of torpor. The present study investigates the influence of body mass on the occurrence of torpor and also the pattern of torpor (i.e. minimum body temperature, metabolic rate, and the duration of torpor). The two small dasyurid marsupials Planigale gilesi (8.3 g) and Ningaui yvonneae (11.6 g) entered torpor frequently when food was available; withdrawal of food increased the occurrence of torpor to almost 100%. Minimum body temperatures during torpor in both species were lower and the torpor duration was longer than for most larger dasyurid species studied so far. These findings suggest that the thermal stress on these very small species exerts a strong selective pressure to enhance daily torpor episodes for reduction of heat loss to the environment.

scholarly journals Heat shock factor 2 is required for maintaining proteostasis against febrile-range thermal stress and polyglutamine aggregation

2011 ◽  
Vol 22 (19) ◽  
pp. 3571-3583 ◽  
Author(s):  
Toyohide Shinkawa ◽  
Ke Tan ◽  
Mitsuaki Fujimoto ◽  
Naoki Hayashida ◽  
Kaoru Yamamoto ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Heat Shock ◽  
Protein Misfolding ◽  
Reproductive Organs ◽  
Heat Shock Factors ◽  
Mild Heat ◽  
Promising Therapeutic Target ◽  
Αb Crystallin ◽  
Shock Proteins ◽  
Polyglutamine Protein

Heat shock response is characterized by the induction of heat shock proteins (HSPs), which facilitate protein folding, and non-HSP proteins with diverse functions, including protein degradation, and is regulated by heat shock factors (HSFs). HSF1 is a master regulator of HSP expression during heat shock in mammals, as is HSF3 in avians. HSF2 plays roles in development of the brain and reproductive organs. However, the fundamental roles of HSF2 in vertebrate cells have not been identified. Here we find that vertebrate HSF2 is activated during heat shock in the physiological range. HSF2 deficiency reduces threshold for chicken HSF3 or mouse HSF1 activation, resulting in increased HSP expression during mild heat shock. HSF2-null cells are more sensitive to sustained mild heat shock than wild-type cells, associated with the accumulation of ubiquitylated misfolded proteins. Furthermore, loss of HSF2 function increases the accumulation of aggregated polyglutamine protein and shortens the lifespan of R6/2 Huntington's disease mice, partly through αB-crystallin expression. These results identify HSF2 as a major regulator of proteostasis capacity against febrile-range thermal stress and suggest that HSF2 could be a promising therapeutic target for protein-misfolding diseases.

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 Thermal–Fluid–Solid Coupling Analysis on the Temperature and Thermal Stress Field of a Nickel-Base Superalloy Turbine Blade

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3315
Author(s):  
Liuxi Cai ◽  
Yao He ◽  
Shunsen Wang ◽  
Yun Li ◽  
Fang Li
Keyword(s):  
Thermal Stress ◽  
Temperature Gradient ◽  
Turbine Blade ◽  
Turbine Blades ◽  
Nickel Base Superalloy ◽  
Barrier Coating ◽  
Thermal Stress Field ◽  
Nickel Base ◽  
Stress Damage ◽  
Superalloy Turbine Blade

Based on the establishment of the original and improved models of the turbine blade, a thermal–fluid–solid coupling method and a finite element method were employed to analyze the internal and external flow, temperature, and thermal stress of the turbine blade. The uneven temperature field, the thermal stress distribution characteristics of the composite cooling turbine blade under the service conditions, and the effect of the thickness of the thermal barrier coating (TBC) on the temperature and thermal stress distributions were obtained. The results show that the method proposed in this paper can better predict the ablation and thermal stress damage of turbine blades. The thermal stress of the blade is closely related to the temperature gradient and local geometric structure of the blade. The inlet area of the pressure side-platform of the blade, the large curvature region of the pressure tip of the blade, and the rounding between the blade body and the platform on the back of the blade are easily damaged by thermal stress. Cooling structure optimization and thicker TBC thickness can effectively reduce the high temperature and temperature gradient on the surface and inside of the turbine blade, thereby reducing the local high thermal stress.

Rancang Bangun Pengukur Suhu Tubuh Dengan Multi Sensor Untuk Mencegah Penyebaran Covid-19

2021 ◽  
Vol 5 (3) ◽  
pp. 543-549
Author(s):  
Helmy Yudhistira Putra ◽  
Utomo Budiyanto
Keyword(s):  
Body Temperature ◽  
Temperature Measurement ◽  
Temperature Sensor ◽  
The Body ◽  
Body Temperatures ◽  
Heat Measurement ◽  
Turn On ◽  
Measurement Results ◽  
Door Lock ◽  
Body Heat

During the COVID-19 pandemic, the price of preventive equipment such as masks and hand sanitizers has increased significantly. Likewise, thermometers are experiencing an increase and scarcity, this tool is also sought after by many companies for screening employees and guests before entering the building to detect body temperatures that are suspected of being positive for COVID-19. The use of a thermometer operated by humans is very risky because dealing directly with people who could be ODP (People Under Monitoring/Suscpected ) or even positive for COVID-19, therefore we need tools for automatic body temperature screening and do not involve humans for the examination. This research uses the MLX-90614 body temperature sensor equipped with an ultrasonic support sensor to detect movement and measure the distance between the forehead and the temperature sensor so that the body heat measurement works optimally, and a 16x2 LCD to display the temperature measurement results. If the measured body temperature is more than 37.5 ° C degrees Celsius then the buzzer will turn on and the selenoid door lock will not open and will send a notification to the Telegram messaging application. The final result obtained is the formation of a prototype device for measuring body temperature automatically without the need to involve humans in measuring body temperature to control people who want to enter the building so as to reduce the risk of COVID-19 transmission

scholarly journals Effect of Hypothermia in the Emergency Department on the Outcome of Trauma Patients: A Cross-Sectional Analysis

2018 ◽  
Vol 15 (8) ◽  
pp. 1769 ◽  
Author(s):  
Ting-Min Hsieh ◽  
Pao-Jen Kuo ◽  
Shiun-Yuan Hsu ◽  
Peng-Chen Chien ◽  
Hsiao-Yun Hsieh ◽  
...  
Keyword(s):  
Logistic Regression ◽  
Regression Analysis ◽  
Body Temperature ◽  
Propensity Score ◽  
Logistic Regression Analysis ◽  
Multivariate Logistic Regression Analysis ◽  
Trauma Patients ◽  
Body Temperatures ◽  
Multivariate Logistic Regression ◽  
Mortality Outcome

This study aimed to assess whether hypothermia is an independent predictor of mortality in trauma patients in the condition of defining hypothermia as body temperatures of <36 °C. Data of all hospitalized adult trauma patients recorded in the Trauma Registry System at a level I trauma center between 1 January 2009 and 12 December 2015 were retrospectively reviewed. A multivariate logistic regression analysis was performed in order to identify factors related to mortality. In addition, hypothermia and normothermia were defined as temperatures <36 °C and from 36 °C to 38 °C, respectively. Propensity score-matched study groups of hypothermia and normothermia patients in a 1:1 ratio were grouped for mortality assessment after adjusting for potential confounders such as age, sex, preexisting comorbidities, and injury severity score (ISS). Of 23,705 enrolled patients, a total of 401 hypothermic patients and 13,368 normothermic patients were included in this study. Only 3.0% of patients had hypothermia upon arrival at the emergency department (ED). Compared to normothermic patients, hypothermic patients had a significantly higher rate of abbreviated injury scale (AIS) scores of ≥3 in the head/neck, thorax, and abdomen and higher ISS. The mortality rate in hypothermic patients was significantly higher than that in normothermic patients (13.5% vs. 2.3%, odds ratio (OR): 6.6, 95% confidence interval (CI): 4.86–9.01, p < 0.001). Of the 399 well-balanced propensity score-matched pairs, there was no significant difference in mortality (13.0% vs. 9.3%, OR: 1.5, 95% CI: 0.94–2.29, p = 0.115). However, multivariate logistic regression analysis revealed that patients with low body temperature were significantly associated with the mortality outcome. This study revealed that low body temperature is associated with the mortality outcome in the multivariate logistic regression analysis but not in the propensity score matching (PSM) model that compared patients with hypothermia defined as body temperatures of <36 °C to those who had normothermia. These contradicting observations indicated the limitation of the traditional definition of body temperature for the diagnosis of hypothermia. Prospective randomized control trials are needed to determine the relationship between hypothermia following trauma and the clinical outcome.

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