Disorders of body temperature

From feeling chilly to burning up: How thermal signals shape the physiological state of the body and impact physical, emotional, and social well-being

This review examines the role of thermal interoception-awareness of body temperature-in shaping physiological states and its impact on physical, emotional, and social well-being. We describe the neural pathways and mechanisms involved in thermal processing and environmental heat exchange and how thermal interoception influences both autonomic and behavioral responses, contributing to survival and homeostasis. Additionally, the review highlights the significance of thermal signals and thermoregulation in determining higher-order cognitive and emotional functions, such as regulating sleep patterns and activity levels, monitoring physical well-being, regulating emotions, and even social interactions. We describe the existing instruments for assessing body temperature and thermal awareness and call for further research to investigate the role of thermal interoception in emotional and social domains. We also discuss potential therapeutic applications, particularly in the context of psychosomatic and neurological disorders characterized by emotional dysregulation, disrupted sleep and mood patterns, social difficulties, and alterations in self-consciousness.

Accuracy, precision and diagnostic accuracy of oral thermometry in pediatric patients

PURPOSE

To determine the accuracy and precision of oral thermometry in pediatric patients, along with its sensitivity and specificity for detecting fever and hypothermia, with rectal thermometry as reference standard.

DESIGN AND METHODS

This method-comparison study enrolled patients aged between 6 and 17 years, admitted to the surgical ward during a 21-month period. KD-2150 and IVAC Temp Plus II were used for oral and rectal temperature measurements respectively. Fever and hypothermia were defined as core temperature ≥38.0 °C and ≤ 35.9 °C respectively. Accuracy and precision of oral thermometry were determined by the Bland-Altman method. Sensitivity, specificity, positive and negative predictive value, and correct classification of oral temperature cutoffs for detecting fever and hypothermia were calculated.

RESULTS

Based on power analysis, 100 pediatric patients were enrolled. The mean difference between oral and rectal temperatures was -0.34 °C, with 95 % limits of agreement ranging between -0.52 and -0.16. Sensitivity and specificity of oral thermometry for detecting fever were 0.50 and 1.0 respectively; its sensitivity and specificity for detecting hypothermia were 1.0 and 0.88 respectively. The oral temperature value of 37.6 °C provided excellent sensitivity for detecting fever, while the value of 35.7 °C provided optimal sensitivity and specificity for detecting hypothermia.

CONCLUSIONS

Oral thermometry had low sensitivity for detecting fever and suboptimal specificity for detecting hypothermia; thus, temperature values <38.0 °C and <36.0 °C cannot exclude fever and confirm hypothermia respectively with high certainty.

PRACTICE IMPLICATIONS

Diagnostic accuracy of oral thermometry can be improved by the use of oral temperature thresholds <38.0 °C for detecting fever and <35.9 °C for detecting hypothermia.

The Structural and Thermal properties of Badarashma Pishti

BACKGROUND

Lapis judaicus, or Jews stone (Badarashma), has been used in treating kidney and bladder stones since ancient times by Ayurvedic and Unani medicinal practitioners. A limited number of studies have been carried out using Ayurvedic preparations derived from gems or precious stones that were used traditionally. In Ayurveda, Rasa Shastra includes the fabrication of Bhasmas and Pishti.

OBJECTIVE

This study aimed to prepare and characterize Badarashma Pishti formulation (Lapis judaicus microparticles) and investigate its structural and thermal properties.

MATERIALS AND METHODS

The microparticles were prepared by subjecting purified powder of Lapis judaicus to a wet levigation (Bhavana) process. Characterizations were done using Fourier transform infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC), thermo-gravimetry analysis (TGA), energy-dispersive X-ray (EDAX) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM) analysis. Physicochemical characterization, elemental analysis, particle size distribution study, and identification of heavy metals were also performed.

RESULTS

A standard operating procedure was developed to formulate Badarashma Pishti. The obtained microparticles were irregularly shaped with a size of 4.290 ± 0.472 μm, confirmed in SEM images. The FTIR and XRD of prepared Badarashma Pishti samples revealed the presence of calcite, quartz, and aragonite minerals. The results of EDAX also confirmed the presence of Ca, Mg, O, and Si elements.

CONCLUSION

The proposed study results reveal great insights for determining the authenticity, purity, and standardization parameters of inorganic mineral drugs, proving to be a useful delivery system for treating renal calculi.

Association between cooling temperature and outcomes of patients with heat stroke

This study explored the relationship between body temperature and adverse outcomes in patients with heat stroke to identify the optimal target body temperature within the first 24 h. This retrospective, multicentre study enrolled 143 patients admitted to the emergency department and diagnosed with heat stroke. The primary outcome was the in-hospital mortality rate, while secondary outcomes included the presence and number of damaged organs and neurological sequelae at discharge. A body temperature curve was built using a generalized additive mixed model, and the association between body temperatures and outcomes was established by logistic regression. The threshold and saturation effects were used to explore the targeted body temperature management. Cases were divided into the surviving and non-surviving groups. The cooling rate within the first 2 h was significantly higher in the survival group than the non-survival group (β: 0.47; 95% confidence interval [CI]: 0.09-0.84; P = 0.014), while the non-survival group exhibited a lower body temperature within 24 h (β: - 0.06; 95% CI: - 0.08 to - 0.03; P ≤ 0.001). Body temperature after 2 h (odds ratio [OR]: 2.27; 95% CI: 1.14-4.50; P = 0.019) and lowest temperature within 24 h (OR: 0.18; 95% CI: 0.06-0.55; P = 0.003) were significantly related to in-hospital mortality rate. When the body temperature at 0.5 h was 38.5-40.0 °C, the number of damaged organs was at its lowest. In patients with heat stroke, both hyperthermia and hypothermia were associated with adverse outcomes. Hence, an accurate body temperature management is required during the early stages of care.

Consideration of the importance of measuring thermal discomfort in biomedical research

Core temperature stability is the result of a dynamically regulated balance of heat loss and gain, which is not reflected by a simple thermometer reading. One way in which these changes manifest is in perceived thermal comfort, 'feeling too cold' or 'feeling too hot', which can activate stress pathways. Unfortunately, there is surprisingly little preclinical research that tracks changes in perceived thermal comfort in response to either disease progression or various treatments. Without measuring this endpoint, there may be missed opportunities to evaluate disease and therapy outcomes in murine models of human disease. Here, we discuss the possibility that changes in thermal comfort in mice could be a useful and physiologically relevant measure of energy trade-offs required under various physiological or pathological conditions.

Temperature variability increases the onset risk of ischemic stroke: A 10-year study in Tianjin, China

Background

Epidemiological evidence suggests a correlation between ambient temperature and ischemic stroke. However, evidence on the impact of daily temperature variability on the onset of ischemic stroke is lacking and limited.

Objective

We aimed to investigate the short-term association between temperature variability and ischemic stroke occurrence in Tianjin.

Methods

We performed a 10-year analysis of ischemic stroke patients hospitalized in two affiliated hospitals of Tianjin Medical University from 2011 to 2020. Daily meteorological data were collected from the Tianjin Meteorological Bureau. Temperature variability was calculated from the standard deviation (SD) of daily minimum and maximum temperatures over exposure days. A quasi-Poisson generalized linear regression combined with distributed lag non-linear model (DLNM) was used to estimate the effect of temperature variability on daily stroke onset, while controlling for daily mean temperature, relative humidity, long-term trend and seasonality, public holiday, and day of the week.

Results

Temperature variability was positively associated with ischemic stroke. A 1°C increase in temperature variability at 0-1 days (TV_0-1) was associated with a 4.1% (1.9-6.3%) increase of ischemic stroke onset. In a stratified analysis, men, people aged ≤65 years, and individuals with pre-existing hypertension, hyperlipidemia, hyperhomocysteinemia were more susceptible to temperature variability. Furthermore, the influence pattern of temperature variability on ischemic stroke was different in the cold season (November-April) and the warm season (May-October).

Conclusion

Our findings suggested that short-term temperature variability exposure could increase the risk of ischemic stroke, which may provide new insights into the impact of climate change on health.

Bioimpedance-Derived Membrane Capacitance: Clinically Relevant Sources of Variability, Precision, and Reliability

Membrane capacitance (CM), a bioimpedance-derived measure of cell membrane health, has been suggested as an indicator of health status. However, there are few published data to support its use in clinical settings. Hence, this study evaluated clinically relevant sources of variation, precision, and reliability of CM measurements. This longitudinal study included 60 premenopausal women. Sources of variability (e.g., demographics, body composition, serum measures, diet) were identified by stepwise regression. Precision and reliability were assessed by the coefficient of variation (CV), intraclass correlation coefficients (ICC), and technical error of the measurement (TEM) for intra-day (30 min apart) and inter-day measurements (7-14 days apart). Body composition, temperature, and metabolic activity were identified as sources of variability. CM measurements had high precision (CV = 0.42%) and high reliability for intra-day (ICC = 0.996) and inter-day (ICC = 0.959) measurements, independent of menstrual cycle and obesity status. Our results showed that CM measurements are sensitive to clinical factors and have high precision and reliability. The results of this study suggest that CM is sufficiently reliable for health status monitoring in conditions with variation in body composition, metabolic activity, or body temperature among premenopausal women.

Deregulation of HSF1-mediated endoplasmic reticulum unfolded protein response promotes cisplatin resistance in lung cancer cells

Mild hypothermia can induce apoptotic cell death in many cancer cells, but the underlying mechanisms remain unclear. In a genetic screen in Caenorhabditis elegans, we found that impaired endoplasmic reticulum unfolded protein response (UPR^ER ) increased animal survival after cold shock. Consistently, in normal human lung cells, decreasing culture temperature from 37 to 30 °C activated UPR^ER and promoted cell death. However, lung adenocarcinoma cells were impaired in UPR^ER induction and resistant to hypothermia-induced cell death. Mechanistically, hypothermic stress increased HSF1 levels, which in turn activated UPR^ER to promote apoptotic cell death. HSF1 expression was associated with UPR^ER genes in normal tissues, but such association was lost in many cancers, especially lung adenocarcinoma. Activating UPR^ER enhanced the cytotoxicity of chemotherapy drugs cisplatin preferentially in cancer cells. Consistently, cancer patients with higher UPR^ER expression had generally better prognosis. Together, our study on hypothermia has led to the discovery of HSF1-UPR^ER in the regulation of drug sensitivity in lung cancer cells, providing novel thoughts on developing new strategies against chemoresistance.

R, Patel PH, Bazan DZ, Mora A, Samuel N, Mingle AC, Leon LR, Varon J, Surani S. Drug-Induced Hyperthermia Review

Humans maintain core body temperature via a complicated system of physiologic mechanisms that counteract heat/cold fluctuations from metabolism, exertion, and the environment. Overextension of these mechanisms or disruption of body temperature homeostasis leads to bodily dysfunction, culminating in a syndrome analogous to exertional heat stroke (EHS). The inability of this thermoregulatory process to maintain the body temperature is caused by either thermal stress or certain drugs. EHS is a syndrome characterized by hyperthermia and the activation of systemic inflammation. Several drug-induced hyperthermic syndromes may resemble EHS and share common mechanisms. The purpose of this article is to review the current literature and compare exertional heat stroke (EHS) to three of the most widely studied drug-induced hyperthermic syndromes: malignant hyperthermia (MH), neuroleptic malignant syndrome (NMS), and serotonin syndrome (SS). Drugs and drug classes that have been implicated in these conditions include amphetamines, diuretics, cocaine, antipsychotics, metoclopramide, selective serotonin reuptake inhibitors (SSRIs), tricyclic antidepressants (TCAs), and many more. Observations suggest that severe or fulminant cases of drug-induced hyperthermia may evolve into an inflammatory syndrome best described as heat stroke. Their underlying mechanisms, symptoms, and treatment approaches will be reviewed to assist in accurate diagnosis, which will impact the management of potentially life-threatening complications.

Metabolic syndrome as a common comorbidity in adults with hypothalamic dysfunction

OBJECTIVE

Hypothalamic dysfunction (HD) results in various endocrine disorders and is associated with an increased risk of metabolic comorbidities. This study aimed to analyze the clinical characteristics and metabolic abnormalities of adults with HD of various causes.

METHODS

This study retrospectively reviewed adults with HD treated at our center between August 1989 and October 2020. Metabolic characteristics of patients were compared to those of age-, sex-matched lean, and body mass index (BMI)-matched controls.

RESULTS

Temperature dysregulation (61.0%) was the most common hypothalamic physiological dysfunction. At least one anterior pituitary hormone deficiency was observed in 50 patients (84.7%), with hypogonadotropic hypogonadism being the most frequently observed. Metabolic syndrome was confirmed in 31 patients (52.5%) and was significantly more prevalent in those with panhypopituitarism or overweight/obesity. Metabolic syndrome (MetS) was significantly more common in patients with HD than in both lean and BMI-matched controls (P < 0.001 and P = 0.030, respectively). Considering the components of MetS, elevated fasting glucose levels were significantly more common in patients with HD than in BMI-matched controls (P = 0.029). Overweight/obesity and panhypopituitarism were significant risk factors for MetS in the multivariate analysis on patients with HD. Moreover, in the multivariate analysis on patients and BMI-matched control, HD was a significant risk factor of MetS (P=0.035, OR 2.919) after adjusted for age, sex and BMI.

CONCLUSIONS

Temperature dysregulation and hypogonadotropic hypogonadism are the most common physiological and endocrine dysfunctions, respectively. MetS and unfavorable metabolic profiles were prevalent in adults with HD. HD was a significant risk factor of MetS after adjusted for BMI.

Beneficial Effects of Receiving Johrei on General Health or Hypothermia Tendency

OBJECTIVES

Johrei is a type of biofield therapy that is said to bring physical and mental well-being to the recipient. This study sought to measure changes in body temperature and circulation resulting from Johrei treatment, for generally healthy subjects and for individuals with a tendency toward hypothermia.

PARTICIPANTS

A total of 199 qualified Johrei practitioners and 144 non-qualified operators provided Johrei and placebo treatments, respectively. Volunteer subjects -186 in general health and 39 with a hypothermia tendency - participated in this study to receive either or both of these treatments.

METHODS

Each subject was given a 10 min treatment daily by either a qualified practitioner or a non-qualified operator. The effects on subjects of receiving each treatment were compared by observing quantitative changes in blood flow and surface body temperature after a course of treatment.

RESULTS

A total of 107 healthy subjects were randomly assigned to the qualified-practitioner group or the non-qualified operator group. Treatment by qualified practitioners significantly enhanced blood flow and surface body temperature in the subjects' designated neck area compared to that in treatment by non-qualified operators. This finding was further corroborated by a comparative experiment in which each healthy subject was treated by both a qualified practitioner and a non-qualified operator. These results indicate that only the qualified-practitioner treatment increased the subject's-blood flow and surface body temperature. Similarly, in a comparative study of qualified-practitioner treatment against non-qualified-operator treatment, subjects tending toward hypothermia showed increased blood flow and elevated body temperature with only the authentic Johrei treatment.

In vitro effects of temperature on red blood cell deformability and membrane stability in human and various vertebrate species

BACKGROUND

The effects of temperature on micro-rheological variables have not been completely revealed yet.

OBJECTIVE

To investigate micro-rheological effects of heat treatment in human, rat, dog, and porcine blood samples.

METHODS

Red blood cell (RBC) - buffer suspensions were prepared and immersed in a 37, 40, and 43°C heat-controlled water bath for 10 minutes. Deformability, as well as mechanical stability of RBCs were measured in ektacytometer. These tests were also examined in whole blood samples at various temperatures, gradually between 37 and 45°C in the ektacytometer.

RESULTS

RBC deformability significantly worsened in the samples treated at 40 and 43°C, more expressed in human, porcine, rat, and in smaller degree in canine samples. The way of heating (incubation vs. ektacytometer temperation) and the composition of the sample (RBC-PBS suspension or whole blood) resulted in the different magnitude of RBC deformability deterioration. Heating affected RBC membrane (mechanical) stability, showing controversial alterations.

CONCLUSION

Significant changes occur in RBC deformability by increasing temperature, showing inter-species differences. The magnitude of alterations is depending on the way of heating and the composition of the sample. The results may contribute to better understanding the micro-rheological deterioration in hyperthermia or fever.

Diagnostic accuracy of oral thermometry for fever detection in adult patients: literature review and meta-analysis

AIMS AND OBJECTIVES

To synthesise the evidence on the accuracy and precision of oral thermometry in adult patients, as well as on its sensitivity and specificity for fever detection.

BACKGROUND

Oral thermometry has long been used in various clinical settings thanks to its rapid, safe and convenient measurements, which are easy to obtain and minimally prone to operator errors.

DESIGN

Literature review and meta-analysis that adhered to the PRISMA statement.

METHODS

By using key terms, literature searches were conducted in CINAHL, PubMed, Web of Science, Scopus and Cochrane Library. Method-comparison studies, which were published from January 1990 to December 2020 in English-language, peer-reviewed journals, compared oral temperature measurements with invasive thermometry ones, and were conducted on patients ≥18 years, were included. Methodological quality of selected studies was evaluated with QUADAS-2.

RESULTS

Sixteen articles were selected for inclusion. Risk of bias was assessed as low in most of them. Quantitative synthesis indicated that pooled mean oral temperature was lower than core temperature by .07℃, with 95% limits of agreement ranging between -.22℃ and .08℃. Pooled sensitivity and specificity for fever detection (defined as core temperature ≥38℃ in most studies) were .53 (95% confidence interval, .39-.66) and .98 (95% confidence interval, .97-.99), respectively. Sensitivity analysis indicated larger temperature underestimation in case rectal temperature was used as reference standard.

CONCLUSION

Despite its satisfactory accuracy, precision and specificity, oral thermometry has low sensitivity for fever detection, which entails a high number of false-negative readings and uncertainty for excluding fever in patients found to be non-febrile.

RELEVANCE TO CLINICAL PRACTICE

Oral thermometry cannot be recommended for replacing invasive thermometry methods in hospitalised adult patients, considering the high incidence of fever in them and possible negative effects of missing fever for patient diagnosis and outcomes.

[Spontaneous periodic hypothermia syndrome: A systematic review of the literature]

INTRODUCTION

Periodic spontaneous hypothermia syndrome (PSHS), also known as hypersudation-hypothermia syndrome, is a rare condition characterised by the occurrence of paroxysmal attacks of spontaneous hypothermia occurring without age limit. Few studies have attempted to synthesise the available data on PSHS. The objective of this study was to summarize the literature on this condition.

METHODS

A literature review was conducted using the Pubmed and ScienceDirect databases. Cases from a registry of PSHS initiated at the CHU of Saint-Étienne were added to the analysis. For each clinical case, clinical, biological and morphological data as well as therapeutic management and evolution were collected.

RESULTS

Seventy-one cases of PSHS were collected. The median age at symptom onset was 21.5 years. The clinical sign most frequently associated with hypothermia was the presence of hyperhidrosis. The triad of hypothermia-hypersudation-agenesis of the corpus callosum was present in 35.7% of cases.

CONCLUSION

PSHS remains a poorly known cause of hypothermia, without consensual therapeutic options. The need to better describe cases and obtain more long-term data will allow a better definition and knowledge of this syndrome.

Virtual Screening of Cablin Patchouli Herb as a Treatment for Heat Stress: A Study Based on Network Pharmacology, Molecular Docking, and Experimental Verification

Heat-related diseases have long been known to damage the structure and function of essential macromolecules such as proteins, lipids, and nucleic acids, thereby compromising the integrity of cells and tissues and the physiological functions of the entire organism. Heat stress is the physical discomfort caused by overheating the body and is also the initial manifestation of heat-related diseases. Cablin patchouli herb (CPB) has been used in China for two thousand years and has been used to treat heat stress, but to date, no related mechanistic research is available. In this study, KEGG and PPI networks and the TCMSP and GEO databases were used to explore the components of CPB in relation to heat stress: quercetin, genkwanin, irisolidone, 3,23-dihydroxy-12-oleanen-28-oic acid, and quercetin 7-O-β-D-glucoside. The targets identified were EGFR, NCOA1, FOS, HIF1A, NFKBIA, and NCOA2; these proteins were verified by molecular docking and experimental verification. In short, our research represents the first report on the use of the traditional Chinese medicine CPB to treat heat stress and thus has pioneering significance.

Simultaneous localization of multiple tumors from thermogram of tissue phantom by using a novel optimization algorithm inspired by hunting dogs

The objective of this study is to couple the contact thermography method with a novel optimization algorithm to rapidly detect and localize the soft tissue tumor. To this end, experiments are carried out on tissue-mimicking phantoms containing resistance heaters to simulate the embedded tumors. An examiner robot is used to measure the temperature of the tissue surface. The time required for the examination of the tissue surface is reduced by developing a novel optimization algorithm called the Hunter Algorithm (HA). In the HA, population individuals are called the hunters, and the global maximum is referred to as the prey. The maximum temperature occurs at the location of the tumor. By the end of the hunting procedure, a flock of hunters converges to the maximum temperature and reaches the tumor while the examination time is significantly reduced. Performance of the HA is evaluated by applying the Genetic Algorithm (GA) and the Particle Swarm Optimization (PSO) algorithm to 11 test functions as minimization problems. It is observed that for the Ackley's function, as an example, the HA finds the global minimum after the 10th iteration with an accuracy of 10^-4, while the PSO converges with the same accuracy after the 30th iteration and the accuracy of the GA remains about 0.002. In addition, the results show that the contact thermography in conjunction with the HA is of clinical importance in accurate detection of multiple tumors and small and deeply located tumors with insignificant thermal effects on the tissue surface.

Identification of whole blood mRNA and microRNA biomarkers of tissue damage and immune function resulting from amphetamine exposure or heat stroke in adult male rats

This work extends the understanding of how toxic exposures to amphetamine (AMPH) adversely affect the immune system and lead to tissue damage. Importantly, it determines which effects of AMPH are and are not due to pronounced hyperthermia. Whole blood messenger RNA (mRNA) and whole blood and serum microRNA (miRNA) transcripts were identified in adult male Sprague-Dawley rats after exposure to toxic AMPH under normothermic conditions, AMPH when it produces pronounced hyperthermia, or environmentally-induced hyperthermia (EIH). mRNA transcripts with large increases in fold-change in treated relative to control rats and very low expression in the control group were a rich source of organ-specific transcripts in blood. When severe hyperthermia was produced by either EIH or AMPH, significant increases in circulating organ-specific transcripts for liver (Alb, Fbg, F2), pancreas (Spink1), bronchi/lungs (F3, Cyp4b1), bone marrow (Np4, RatNP-3b), and kidney (Cesl1, Slc22a8) were observed. Liver damage was suggested also by increased miR-122 levels in the serum. Increases in muscle/heart-enriched transcripts were produced by AMPH even in the absence of hyperthermia. Expression increases in immune-related transcripts, particularly Cd14 and Vcan, indicate that AMPH can activate the innate immune system in the absence of hyperthermia. Most transcripts specific for T-cells decreased 50–70% after AMPH exposure or EIH, with the noted exception of Ccr5 and Chst12. This is probably due to T-cells leaving the circulation and down-regulation of these genes. Transcript changes specific for B-cells or B-lymphoblasts in the AMPH and EIH groups ranged widely from decreasing ≈ 40% (Cd19, Cd180) to increasing 30 to 100% (Tk1, Ahsa1) to increasing ≥500% (Stip1, Ackr3). The marked increases in Ccr2, Ccr5, Pld1, and Ackr3 produced by either AMPH or EIH observed in vivo provide further insight into the initial immune system alterations that result from methamphetamine and AMPH abuse and could modify risk for HIV and other viral infections.

Effects of Temperature on Heteromeric Kv11.1a/1b and Kv11.3 Channels

Kv11.1 channels are crucial in cardiac physiology, and there is increasing evidence of physiological roles of different Kv11 channels outside the heart. The HERG (human Kv11.1a) channel has previously been shown to carry substantially more current at elevated temperatures, and we have now comparably investigated the temperature dependence of neuronal Kv11.3 channels and the more ubiquitous heteromeric Kv11.1a/1b channels. Transiently expressed rat Kv11 channels were studied at 21°C, 30°C, and 35°C. At near-physiological temperature, the maximal sustained outward current density was almost three times the mean value obtained at room temperature for Kv11.1a/1b, and increased by ∼150% for Kv11.3. For both channels, reduced inactivation contributed to the current increase at higher temperature. Elevated temperature moved Kv11.1a/1b isochronal activation curves to more negative potentials, but shifted the potential of half-maximal Kv11.3 channel activation to more depolarized values and reduced its voltage sensitivity. Thus, increased temperature stabilized the open state over the closed state of Kv11.1a/1b channels and exerted the opposite effect on Kv11.3 channel activation. Both Kv11 channels exhibited an overall high temperature sensitivity of most gating parameters, with remarkably high Q10 factors of ∼5 for the rate of Kv11.1a/1b activation. The Q10 factors for Kv11.3 gating were more uniform, but still higher for activation than for inactivation kinetics. The results demonstrate that characteristic differences between Kv11.1a/1b and Kv11.3 determined at room temperature do not necessarily apply to physiological conditions. The data provided here can aid in the design of models that will enhance our understanding of the role of Kv11 currents in excitable cells.

Neurologic complications of acute environmental injuries

Environmental injuries can result in serious neurologic morbidity. This chapter reviews neurologic complications of thermal burns, smoke inhalation, lightning strikes, electric injury, near drowning, decompression illness, as well as heat stroke and accidental hypothermia. Knowing the pathophysiology and clinical presentation of such injuries is essential to proper management of primary and secondary medical complications. This chapter highlights the most frequently encountered neurologic injuries secondary to common environmental hazards, divided into the topics: injuries related to fire, electricity, water, and the extremes of temperature.

Rapid cooling after acute hyperthermia alters intestinal morphology and increases the systemic inflammatory response in pigs

The study objective was to determine the direct effects of rapid cooling after acute hyperthermia on intestinal morphology and inflammatory response in pigs. In four repetitions, male pigs (N = 36; 88.7 ± 1.6 kg) were exposed to thermoneutrality (TN; n = 3/rep; 19.5 ± 0.1°C) for 6 h or heat stress (HS; 36.4 ± 0.1°C) for 3 h, followed by a 3-h recovery period of rapid cooling (HSRC; n = 3/rep; rapid TN exposure and ice water dousing for 1.5 h) or gradual cooling (HSGC; n = 3/rep; gradual decrease from HS to TN). Rectal (TR) and gastrointestinal tract (TGI) temperatures were obtained every 15 min for 6 h. In repetitions 1 and 2, blood was collected at 60 and 180 min during HS and 30 and 60 min during recovery, and then pigs were euthanized at 180 min of recovery and duodenum, ileum, and colon tissue were collected to evaluate intestinal morphology. HS increased (P < 0.01) maximum TR (40.7°C) and TGI (41.5°C) compared with TN treatment (38.9 and 39.3°C, respectively). Recovery reduced TR (P < 0.01; 0.4°C) in HSRC vs. HSGC pigs, but TGI was similar (40.7°C). HSRC reduced (P < 0.01) villus height-to-crypt depth ratio in the duodenum (34%) and ileum (46%) vs. HSGC pigs. Serum LPS concentration was greater in HSRC pigs (P = 0.04; 68.5% and 52.4%, respectively) compared with TN and HSGC pigs, and TNF-α concentration tended to be greater (P = 0.06; 41.2%) compared with HSGC pigs during recovery. In summary, rapid cooling reduced TR but had no effect on TGI, and this may be linked to increased intestinal damage and a systemic inflammatory response.