scholarly journals Therapeutic Inhaled Sphingosine for Treating Lung Infection in a Mouse Model of Critical Illness

2020 ◽  
Vol 54 (5) ◽  
pp. 1054-1067
Keyword(s):  
Body Temperature ◽  
Pulmonary Infection ◽  
Core Body Temperature ◽  
Cecal Ligation ◽  
Membrane Permeabilization ◽  
Tracheal Epithelium ◽  
Intracellular Acidification ◽  
Significant Drop ◽  
Lung Infections ◽  
Core Body

BACKGROUND/AIMS: Sphingosine, a sphingoid long chain base, is a natural lipid with antimicrobial properties. Recent animal studies have shown that preventive sphingosine inhalation can rescue susceptible mice, such as cystic fibrosis-, burn injured- or aged mice from bacterial pulmonary infection. While preventing lung infections in susceptible patients has obvious clinical merit, treatment strategies for an established infection are also direly needed, particularly in the times of rising antibiotic resistance. Here, we tested the potential of sphingosine in treating an established pulmonary infection. METHODS: We used a cecal ligation and puncture (CLP) model in male CF-1 mice and a Pseudomonas aeruginosa strain that was isolated from a septic patient (P. aeruginosa 762). We determined susceptibility to intranasal infection and ascertained when the pulmonary infection was established by continuous core body temperature monitoring. We quantified sphingosine levels in the tracheal epithelium by immunohistochemistry and studied the effects on sphingosine on bacterial membrane permeabilization and intracellular acidification using fluorescent probes. RESULTS: We first
determined that septic mice are highly susceptible to P. aeruginosa infection 2 days after indu-cing sepsis. Additionally, at this time, sphingosine levels in the tracheal epithelium are significantly reduced as compared to levels in healthy mice. Secondly, upon intranasal Pseudomonas
inoculation, we ascertained that pulmonary infection was established as early as 2.5 h after inoculation as evidenced by a significant drop in core body temperature. Using these times of infection susceptibility and detection (2 days post CLP, 2.5h after inoculation) we treated with inhaled sphingosine and observed pulmonary bacterial loads reduced to levels found in infected healthy mice after inoculation and decreased infection-associated mortality. Further, our data demonstrate that sphingosine induces outer membrane permeabilization, disrupting the membrane potential and leading to intracellular acidification of the bacteria. CONCLUSION: Sphingosine shows efficacy in treating P. aeruginosa lung infections not only prophylactically, but also therapeutically.

Core body temperature changes after sauna exposition in healthy subjects

2012 ◽  
Vol 26 (2) ◽  
Author(s):  
Joanna Pawlak ◽  
Paweł Zalewski ◽  
Jacek J. Klawe ◽  
Monika Zawadka ◽  
Anna Bitner ◽  
...  
Keyword(s):  
Body Temperature ◽  
Healthy Subjects ◽  
Core Body Temperature ◽  
Temperature Changes ◽  
Core Body

scholarly journals Pathophysiology of Fever and Application of Infrared Thermography (IRT) in the Detection of Sick Domestic Animals: Recent Advances

Animals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2316
Author(s):  
Daniel Mota-Rojas ◽  
Dehua Wang ◽  
Cristiane Gonçalves Titto ◽  
Jocelyn Gómez-Prado ◽  
Verónica Carvajal-de la Fuente ◽  
...  
Keyword(s):  
Body Temperature ◽  
Infrared Thermography ◽  
Core Body Temperature ◽  
The Body ◽  
Farm Animals ◽  
Economic Losses ◽  
Febrile Response ◽  
Temperature Range ◽  
Stable Temperature ◽  
Core Body

Body-temperature elevations are multifactorial in origin and classified as hyperthermia as a rise in temperature due to alterations in the thermoregulation mechanism; the body loses the ability to control or regulate body temperature. In contrast, fever is a controlled state, since the body adjusts its stable temperature range to increase body temperature without losing the thermoregulation capacity. Fever refers to an acute phase response that confers a survival benefit on the body, raising core body temperature during infection or systemic inflammation processes to reduce the survival and proliferation of infectious pathogens by altering temperature, restriction of essential nutrients, and the activation of an immune reaction. However, once the infection resolves, the febrile response must be tightly regulated to avoid excessive tissue damage. During fever, neurological, endocrine, immunological, and metabolic changes occur that cause an increase in the stable temperature range, which allows the core body temperature to be considerably increased to stop the invasion of the offending agent and restrict the damage to the organism. There are different metabolic mechanisms of thermoregulation in the febrile response at the central and peripheral levels and cellular events. In response to cold or heat, the brain triggers thermoregulatory responses to coping with changes in body temperature, including autonomic effectors, such as thermogenesis, vasodilation, sweating, and behavioral mechanisms, that trigger flexible, goal-oriented actions, such as seeking heat or cold, nest building, and postural extension. Infrared thermography (IRT) has proven to be a reliable method for the early detection of pathologies affecting animal health and welfare that represent economic losses for farmers. However, the standardization of protocols for IRT use is still needed. Together with the complete understanding of the physiological and behavioral responses involved in the febrile process, it is possible to have timely solutions to serious problem situations. For this reason, the present review aims to analyze the new findings in pathophysiological mechanisms of the febrile process, the heat-loss mechanisms in an animal with fever, thermoregulation, the adverse effects of fever, and recent scientific findings related to different pathologies in farm animals through the use of IRT.

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 Estimation of cardiovascular drift through ear temperature during prolonged steady-state cycling: a study protocol

2021 ◽  
Vol 7 (1) ◽  
pp. e000907
Author(s):  
Giovanni Polsinelli ◽  
Angelo Rodio ◽  
Bruno Federico
Keyword(s):  
Heart Rate ◽  
Steady State ◽  
Body Temperature ◽  
Study Protocol ◽  
External Auditory Canal ◽  
Exercise Intensity ◽  
Core Body Temperature ◽  
Cardiovascular Drift ◽  
Core Body ◽  
Steady State Cycling

IntroductionThe measurement of heart rate is commonly used to estimate exercise intensity. However, during endurance performance, the relationship between heart rate and oxygen consumption may be compromised by cardiovascular drift. This physiological phenomenon mainly consists of a time-dependent increase in heart rate and decrease in systolic volume and may lead to overestimate absolute exercise intensity in prediction models based on heart rate. Previous research has established that cardiovascular drift is correlated to the increase in core body temperature during prolonged exercise. Therefore, monitoring body temperature during exercise may allow to quantify the increase in heart rate attributable to cardiovascular drift and to improve the estimate of absolute exercise intensity. Monitoring core body temperature during exercise may be invasive or inappropriate, but the external auditory canal is an easily accessible alternative site for temperature measurement.Methods and analysisThis study aims to assess the degree of correlation between trends in heart rate and in ear temperature during 120 min of steady-state cycling with intensity of 59% of heart rate reserve in a thermally neutral indoor environment. Ear temperature will be monitored both at the external auditory canal level with a contact probe and at the tympanic level with a professional infrared thermometer.Ethics and disseminationThe study protocol was approved by an independent ethics committee. The results will be submitted for publication in academic journals and disseminated to stakeholders through summary documents and information meetings.

scholarly journals A refined method to monitor arousal from hibernation in the European hamster

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Fredrik A. F. Markussen ◽  
Vebjørn J. Melum ◽  
Béatrice Bothorel ◽  
David G. Hazlerigg ◽  
Valérie Simonneaux ◽  
...  
Keyword(s):  
Body Temperature ◽  
Core Body Temperature ◽  
Behavioural Adaptation ◽  
Ventilation Frequency ◽  
Reduced Body ◽  
Brown Adipose ◽  
Invasive Method ◽  
Warming Rate ◽  
Core Body ◽  
Environmental Temperatures

Abstract Background Hibernation is a physiological and behavioural adaptation that permits survival during periods of reduced food availability and extreme environmental temperatures. This is achieved through cycles of metabolic depression and reduced body temperature (torpor) and rewarming (arousal). Rewarming from torpor is achieved through the activation of brown adipose tissue (BAT) associated with a rapid increase in ventilation frequency. Here, we studied the rate of rewarming in the European hamster (Cricetus cricetus) by measuring both BAT temperature, core body temperature and ventilation frequency. Results Temperature was monitored in parallel in the BAT (IPTT tags) and peritoneal cavity (iButtons) during hibernation torpor-arousal cycling. We found that increases in brown fat temperature preceded core body temperature rises by approximately 48 min, with a maximum re-warming rate of 20.9℃*h-1. Re-warming was accompanied by a significant increase in ventilation frequency. The rate of rewarming was slowed by the presence of a spontaneous thoracic mass in one of our animals. Core body temperature re-warming was reduced by 6.2℃*h-1 and BAT rewarming by 12℃*h-1. Ventilation frequency was increased by 77% during re-warming in the affected animal compared to a healthy animal. Inspection of the position and size of the mass indicated it was obstructing the lungs and heart. Conclusions We have used a minimally invasive method to monitor BAT temperature during arousal from hibernation illustrating BAT re-warming significantly precedes core body temperature re-warming, informing future study design on arousal from hibernation. We also showed compromised re-warming from hibernation in an animal with a mass obstructing the lungs and heart, likely leading to inefficient ventilation and circulation.

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