scholarly journals A novel mouse model of heatstroke accounting for ambient temperature and relative humidity

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Kazuyuki Miyamoto ◽  
Keisuke Suzuki ◽  
Hirokazu Ohtaki ◽  
Motoyasu Nakamura ◽  
Hiroki Yamaga ◽  
...  
Keyword(s):  
Gene Expression ◽  
Body Temperature ◽  
Relative Humidity ◽  
Ambient Temperature ◽  
Core Body Temperature ◽  
Heat Exposure ◽  
Organ Damage ◽  
Core Body ◽  
The Impact ◽  
Treatment Water

Abstract Background Heatstroke is associated with exposure to high ambient temperature (AT) and relative humidity (RH), and an increased risk of organ damage or death. Previously proposed animal models of heatstroke disregard the impact of RH. Therefore, we aimed to establish and validate an animal model of heatstroke considering RH. To validate our model, we also examined the effect of hydration and investigated gene expression of cotransporter proteins in the intestinal membranes after heat exposure. Methods Mildly dehydrated adult male C57/BL6J mice were subjected to three AT conditions (37 °C, 41 °C, or 43 °C) at RH > 99% and monitored with WetBulb globe temperature (WBGT) for 1 h. The survival rate, body weight, core body temperature, blood parameters, and histologically confirmed tissue damage were evaluated to establish a mouse heatstroke model. Then, the mice received no treatment, water, or oral rehydration solution (ORS) before and after heat exposure; subsequent organ damage was compared using our model. Thereafter, we investigated cotransporter protein gene expressions in the intestinal membranes of mice that received no treatment, water, or ORS. Results The survival rates of mice exposed to ATs of 37 °C, 41 °C, and 43 °C were 100%, 83.3%, and 0%, respectively. From this result, we excluded AT43. Mice in the AT 41 °C group appeared to be more dehydrated than those in the AT 37 °C group. WBGT in the AT 41 °C group was > 44 °C; core body temperature in this group reached 41.3 ± 0.08 °C during heat exposure and decreased to 34.0 ± 0.18 °C, returning to baseline after 8 h which showed a biphasic thermal dysregulation response. The AT 41 °C group presented with greater hepatic, renal, and musculoskeletal damage than did the other groups. The impact of ORS on recovery was greater than that of water or no treatment. The administration of ORS with heat exposure increased cotransporter gene expression in the intestines and reduced heatstroke-related damage. Conclusions We developed a novel mouse heatstroke model that considered AT and RH. We found that ORS administration improved inadequate circulation and reduced tissue injury by increasing cotransporter gene expression in the intestines.

scholarly journals Circadian Hygiene in the ICU Environment (CHIE) study

2020 ◽  
Vol 22 (4) ◽  
pp. 361-369
Author(s):  
Rob Boots ◽  
◽  
Gabrielle Mead ◽  
Oliver Rawashdeh ◽  
Judith Bellapart ◽  
...  
Keyword(s):  
Body Temperature ◽  
Relative Humidity ◽  
Light Intensity ◽  
Ambient Temperature ◽  
Core Body Temperature ◽  
Sound Intensity ◽  
Nursing Intervention ◽  
Nursing Interventions ◽  
Environmental Measures ◽  
Core Body

Objective: To investigate the environment and care in the intensive care unit (ICU) and its relationship to patient circadian temperature disruption. Design: 30-day, prospective period prevalence study. Setting: 27-bed tertiary ICU. Participants: Patients expected to remain in the ICU for at least 24 hours. Main outcome measures: Temperature, relative humidity, light and sound intensity in the ICU; nursing interventions (using the Therapeutic Intervention Scoring System-28); and core body temperature of ICU patients. Results: Of 28 patients surveyed, 20 (71%) were mechanically ventilated. Median (interquartile range [IQR]) light intensity peaked at 07:00 at 165 (12–1218) lux with a trough at 23:00 of 15 (12–51) lux and was consistently < 100 lux between 21:00 and 06:00. Peak median (IQR) sound intensity was at 07:00 (62.55 [57.87–68.03] dB) while 58.84 (54.81–64.71) dB at 02:00. Ambient temperature and humidity varied with median (IQR) peaks of 23.11°C (22.74–23.31°C) at 16:00 and 44.07% (32.76–51.08%) at 11:00 and median troughs of 22.37°C (21.79–22.88°C) at 05:00 and 39.95% (31.53–47.95%) at 14:00, respectively. Disturbances to sleep during the night occurred due to care activities including linen changes (15 patients, 54%) and bathing (13, 46%). On the day before and the day of the study, 13 patients (47%) and 10 patients (36%), respectively, had a circadian rhythm on core body temperature without an association with illness severity, nursing intervention or environmental measures. Conclusions: The ICU has low light intensity with relative humidity and ambient temperature not aligned to normal human circadian timing. Noise levels are commonly equivalent to conversational speech while patient care procedures interrupt overnight sleep. The contribution of these factors to disrupted CBT rhythmicity is unclear.

scholarly journals The Impact of Central and Peripheral Cyclooxygenase Enzyme Inhibition on Exercise-Induced Elevations in Core Body Temperature

2017 ◽  
Vol 12 (5) ◽  
pp. 662-667 ◽  
Author(s):  
Matthijs T.W. Veltmeijer ◽  
Dineke Veeneman ◽  
Coen C.C.W. Bongers ◽  
Mihai G. Netea ◽  
Jos W. van der Meer ◽  
...  
Keyword(s):  
Heart Rate ◽  
Body Temperature ◽  
Skin Temperature ◽  
Core Body Temperature ◽  
Exercise Tests ◽  
Hypothalamic Temperature ◽  
Set Point ◽  
Exercise Induced ◽  
Core Body ◽  
The Impact

Purpose:Exercise increases core body temperature (TC) due to metabolic heat production. However, the exercise-induced release of inflammatory cytokines including interleukin-6 (IL-6) may also contribute to the rise in TC by increasing the hypothalamic temperature set point. This study investigated whether the exercise-induced increase in TC is partly caused by an altered hypothalamic temperature set point.Methods:Fifteen healthy, active men age 36 ± 14 y were recruited. Subjects performed submaximal treadmill exercise in 3 randomized test conditions: (1) 400 mg ibuprofen and 1000 mg acetaminophen (IBU/APAP), (2) 1000 mg acetaminophen (APAP), and (3) a control condition (CTRL). Acetaminophen and ibuprofen were used to block the effect of IL-6 at a central and peripheral level, respectively. TC, skin temperature, and heart rate were measured continuously during the submaximal exercise tests.Results:Baseline values of TC, skin temperature, and heart rate did not differ across conditions. Serum IL-6 concentrations increased in all 3 conditions. A significantly lower peak TC was observed in IBU/APAP (38.8°C ± 0.4°C) vs CTRL (39.2°C ± 0.5°C, P = .02) but not in APAP (38.9°C ± 0.4°C) vs CTRL. Similarly, a lower ΔTC was observed in IBU/APAP (1.7°C ± 0.3°C) vs CTRL (2.0°C ± 0.5°C, P < .02) but not in APAP (1.7°C ± 0.5°C) vs CTRL. No differences were observed in skin temperature and heart-rate responses across conditions.Conclusions:The combined administration of acetaminophen and ibuprofen resulted in an attenuated increase in TC during exercise compared with a CTRL. This observation suggests that a prostaglandin-E2-induced elevated hypothalamic temperature set point may contribute to the exercise-induced rise in TC.

scholarly journals Impaired Thermogenesis and a Molecular Signature for Brown Adipose Tissue inId2Null Mice

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Peng Zhou ◽  
Maricela Robles-Murguia ◽  
Deepa Mathew ◽  
Giles E. Duffield
Keyword(s):  
Adipose Tissue ◽  
Body Temperature ◽  
Brown Adipose Tissue ◽  
Energy Homeostasis ◽  
Core Body Temperature ◽  
Specific Pattern ◽  
Molecular Signature ◽  
Brown Adipose ◽  
Core Body ◽  
The Impact

Inhibitor of DNA binding 2 (ID2) is a helix-loop-helix transcriptional repressor rhythmically expressed in many adult tissues. Our previous studies have demonstrated thatId2null mice have sex-specific elevated glucose uptake in brown adipose tissue (BAT). Here we further explored the role ofId2in the regulation of core body temperature over the circadian cycle and the impact ofId2deficiency on genes involved in insulin signaling and adipogenesis in BAT. We discovered a reduced core body temperature inId2−/− mice. Moreover, inId2−/− BAT, 30 genes includingIrs1,PPARs, andPGC-1s were identified as differentially expressed in a sex-specific pattern. These data provide valuable insights into the impact ofId2deficiency on energy homeostasis of mice in a sex-specific manner.

scholarly journals Skipping Breakfast for 6 Days Delayed the Circadian Rhythm of the Body Temperature without Altering Clock Gene Expression in Human Leukocytes

Nutrients ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2797 ◽  
Author(s):  
Hitomi Ogata ◽  
Masaki Horie ◽  
Momoko Kayaba ◽  
Yoshiaki Tanaka ◽  
Akira Ando ◽  
...  
Keyword(s):  
Gene Expression ◽  
Body Temperature ◽  
Clock Gene ◽  
Core Body Temperature ◽  
The Core ◽  
Clock Gene Expression ◽  
Meal Timing ◽  
Dim Light ◽  
Core Body ◽  
Skipping Breakfast

Breakfast is often described as “the most important meal of the day” and human studies have revealed that post-prandial responses are dependent on meal timing, but little is known of the effects of meal timing per se on human circadian rhythms. We evaluated the effects of skipping breakfast for 6 days on core body temperature, dim light melatonin onset, heart rate variability, and clock gene expression in 10 healthy young men, with a repeated-measures design. Subjects were provided an isocaloric diet three times daily (3M) or two times daily (2M, i.e., breakfast skipping condition) over 6 days. Compared with the 3M condition, the diurnal rhythm of the core body temperature in the 2M condition was delayed by 42.0 ± 16.2 min (p = 0.038). On the other hand, dim light melatonin onset, heart rate variability, and clock gene expression were not affected in the 2M condition. Skipping breakfast for 6 days caused a phase delay in the core body temperature in healthy young men, even though the sleep–wake cycle remained unchanged. Chronic effects of skipping breakfast on circadian rhythms remain to be studied.

scholarly journals Shift Work Disrupts Circadian Regulation of the Transcriptome in Hospital Nurses

2019 ◽  
Vol 34 (2) ◽  
pp. 167-177 ◽  
Author(s):  
David Resuehr ◽  
Gang Wu ◽  
Russell L. Johnson ◽  
Martin E. Young ◽  
John B. Hogenesch ◽  
...  
Keyword(s):  
Gene Expression ◽  
Body Temperature ◽  
Shift Work ◽  
Core Body Temperature ◽  
Expression Patterns ◽  
Night Shift ◽  
Hospital Nurses ◽  
Large Variability ◽  
Genome Wide ◽  
Core Body

Circadian misalignment between sleep and behavioral/feeding rhythms is thought to lead to various health impairments in shift workers. Therefore, we investigated how shift work leads to genome-wide circadian dysregulation in hospital nurses. Female nurses from the University of Alabama at Birmingham (UAB) Hospital working night shift ( n = 9; 29.6 ± 11.4 y) and day shift ( n = 8; 34.9 ± 9.4 y) participated in a 9-day study measuring locomotor activity and core body temperature (CBT) continuously. Additionally, cortisol and melatonin were assayed and peripheral blood mononuclear cells (PBMCs) were harvested for RNA extraction every 3 h on a day off from work. We saw phase desynchrony of core body temperature, peak cortisol, and dim light melatonin onset in individual night-shift subjects compared with day-shift subjects. This variability was evident even though day- and night-shift nurses had similar sleep timing and scheduled meal times on days off. Surprisingly, the phase and rhythmicity of the expression of the clock gene, PER1, in PBMCs were similar for day-shift and night-shift subjects. Genome-wide microarray analysis of PBMCs from a subset of nurses revealed distinct gene expression patterns between night-shift and day-shift subjects. Enrichment analysis showed that day-shift subjects expressed pathways involved in generic transcription and regulation of signal transduction, whereas night-shift subjects expressed pathways such as RNA polymerase I promoter opening, the matrisome, and endocytosis. In addition, there was large variability in the number of rhythmic transcripts among subjects, regardless of shift type. Interestingly, the amplitude of the CBT rhythm appeared to be more consistent with the number of cycling transcripts for each of the 6 subjects than was melatonin rhythm. In summary, we show that shift-work patterns affect circadian alignment and gene expression in PBMCs.

scholarly journals Novel Analytic Methods Needed for Real-Time Continuous Core Body Temperature Data

2016 ◽  
Vol 39 (1) ◽  
pp. 95-111 ◽  
Author(s):  
Vicki Hertzberg ◽  
Valerie Mac ◽  
Lisa Elon ◽  
Nathan Mutic ◽  
Abby Mutic ◽  
...  
Keyword(s):  
Data Analysis ◽  
Body Temperature ◽  
Real Time ◽  
Time Course ◽  
Core Body Temperature ◽  
Heat Exposure ◽  
Threshold Limit Value ◽  
Limit Value ◽  
Novel Approach ◽  
Core Body

Affordable measurement of core body temperature (Tc) in a continuous, real-time fashion is now possible. With this advance comes a new data analysis paradigm for occupational epidemiology. We characterize issues arising after obtaining Tc data over 188 workdays for 83 participating farmworkers, a population vulnerable to effects of rising temperatures due to climate change. We describe a novel approach to these data using smoothing and functional data analysis. This approach highlights different data aspects compared with describing Tc at a single time point or summaries of the time course into an indicator function (e.g., did Tc ever exceed 38 °C, the threshold limit value for occupational heat exposure). Participants working in ferneries had significantly higher Tc at some point during the workday compared with those working in nurseries, despite a shorter workday for fernery participants. Our results typify the challenges and opportunities in analyzing Big Data streams from real-time physiologic monitoring.

Long-term measurement of body temperature in the southern hairy-nosed wombat (Lasiorhinus latifrons)

2017 ◽  
Vol 39 (1) ◽  
pp. 48 ◽  
Author(s):  
K. A. Descovich ◽  
S. Johnston ◽  
A. Lisle ◽  
V. Nicolson ◽  
T. Janssen ◽  
...  
Keyword(s):  
Body Temperature ◽  
Ambient Temperature ◽  
Core Body Temperature ◽  
Late Winter ◽  
Comprehensive Picture ◽  
Burrow Use ◽  
Core Body ◽  
The Relationship ◽  
Environmental Temperatures

The southern hairy-nosed wombat (Lasiorhinus latifrons) is a nocturnal, fossorial marsupial that has evolved a range of physiological and behavioural adaptations to its semiarid environment. This study describes long-term core body temperature (Tb) of L. latifrons in a population with opportunities for behavioural thermoregulation through burrow use. Tb was measured hourly in 12 captive L. latifrons using implanted dataloggers over a 9-month period from late winter to late autumn. Data were examined for daily patterns, seasonal changes, sex differences and the relationship with environmental conditions (ambient temperature, den temperature and relative humidity). Tb ranged from 30.9 to 38.8°C, and had a distinct nychthemeral rhythm, with peak temperatures occurring at night in line with nocturnal activity. Females had a higher mean Tb (34.9°C) than males (34.4°C). The relationship between external ambient temperature and body temperature was negative, with body temperature decreasing as ambient temperature increased. This study is an important step towards a comprehensive picture of thermoregulation in L. latifrons, which may become vulnerable in the future if environmental temperatures rise and water availability decreases.

The effects of heat stress on cognition in persons with multiple sclerosis

2011 ◽  
Vol 18 (4) ◽  
pp. 489-497 ◽  
Author(s):  
P Hämäläinen ◽  
A Ikonen ◽  
A Romberg ◽  
H Helenius ◽  
J Ruutiainen
Keyword(s):  
Multiple Sclerosis ◽  
Heat Stress ◽  
Body Temperature ◽  
Cognitive Functioning ◽  
Cognitive Deficits ◽  
Core Body Temperature ◽  
Heat Exposure ◽  
Heat Sensitivity ◽  
Serial Addition ◽  
Core Body

Background: Heat sensitivity and cognitive deficits are typical manifestations of multiple sclerosis (MS). Although cognitive deficits are quite well characterized, practically no data exist on the effects of heat on cognitive performances in MS. Objective: To assess the effects of short-term heat stress on cognitive functioning in subjects with MS. Methods: A total of 23 heat-sensitive MS and 19 healthy control (HC) subjects participated. Moderate heat exposure took place in a Finnish sauna. Cognitive functioning was measured with tests of sustained attention and processing speed, the Paced Auditory Serial Addition Test (PASAT 3” and 2”) and the computerized visual vigilance test, before, during and after heat exposure. Results: During the heat exposure, the core body temperature of the MS group rose significantly more ( p = 0.002) than that of the HC group. The heat stress worsened the performance of the MS group in the PASAT 3” ( p = 0.025) but not in the other cognitive measures. The performance in the PASAT 3” was reversed almost to the baseline level only 1- h after the heat exposure. Conclusions: A significant increase in core body temperature during heat stress is associated with a mild and reversible worsening of the PASAT 3” performance, while visual vigilance performance seems to remain almost unaffected.

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