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Cajanding RJM. Current State of Knowledge on the Definition, Pathophysiology, Etiology, Outcomes, and Management of Fever in the Intensive Care Unit. AACN Adv Crit Care 2023; 34:297-310. [PMID: 38033217 DOI: 10.4037/aacnacc2023314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
Fever-an elevated body temperature-is a prominent feature of a wide range of disease conditions and is a common finding in intensive care, affecting up to 70% of patients in the intensive care unit (ICU). The causes of fever in the ICU are multifactorial, and it can be due to a number of infective and noninfective etiologies. The production of fever represents a complex physiological, adaptive host response that is beneficial for host defense and survival but can be maladaptive and harmful if left unabated. Despite any cause, fever is associated with a wide range of cellular, local, and systemic effects, including multiorgan dysfunction, systemic inflammation, poor neurological recovery, and an increased risk of mortality. This narrative review presents the current state-of-the-art knowledge on the definition, pathophysiology, etiology, and outcomes of fever in the ICU and highlights evidence-based findings regarding the management of fever in the intensive care setting.
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Affiliation(s)
- Ruff Joseph Macale Cajanding
- Ruff Joseph Macale Cajanding is a Critical Care Senior Charge Nurse, Adult Critical Care Unit, St Bartholomew's Hospital, Barts Health NHS Trust, King George V Building, West Smithfield EC1A 7BE London, United Kingdom
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2
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Sixtus RP, Bailey DM. Burning fuels burns the brain's bioenergetic bridges: On the importance of physiological resilience. Exp Physiol 2023; 108:1366-1369. [PMID: 37742138 PMCID: PMC10988455 DOI: 10.1113/ep091424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 09/11/2023] [Indexed: 09/25/2023]
Affiliation(s)
- Ryan P. Sixtus
- School of Biomedical Sciences, Sir Martin Evans BuildingCardiff UniversityGlamorganUK
| | - Damian M. Bailey
- Neurovascular Research Laboratory, Faculty of Life Sciences and EducationUniversity of South WalesGlamorganUK
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3
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Zhou Q, Fu X, Xu J, Dong S, Liu C, Cheng D, Gao C, Huang M, Liu Z, Ni X, Hua R, Tu H, Sun H, Shen Q, Chen B, Zhang J, Zhang L, Yang H, Hu J, Yang W, Pei W, Yao Q, Sheng X, Zhang J, Yang WZ, Shen WL. Hypothalamic warm-sensitive neurons require TRPC4 channel for detecting internal warmth and regulating body temperature in mice. Neuron 2023; 111:387-404.e8. [PMID: 36476978 DOI: 10.1016/j.neuron.2022.11.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 06/28/2022] [Accepted: 11/07/2022] [Indexed: 12/12/2022]
Abstract
Precise monitoring of internal temperature is vital for thermal homeostasis in mammals. For decades, warm-sensitive neurons (WSNs) within the preoptic area (POA) were thought to sense internal warmth, using this information as feedback to regulate body temperature (Tcore). However, the cellular and molecular mechanisms by which WSNs measure temperature remain largely undefined. Via a pilot genetic screen, we found that silencing the TRPC4 channel in mice substantially attenuated hypothermia induced by light-mediated heating of the POA. Loss-of-function studies of TRPC4 confirmed its role in warm sensing in GABAergic WSNs, causing additional defects in basal temperature setting, warm defense, and fever responses. Furthermore, TRPC4 antagonists and agonists bidirectionally regulated Tcore. Thus, our data indicate that TRPC4 is essential for sensing internal warmth and that TRPC4-expressing GABAergic WSNs function as a novel cellular sensor for preventing Tcore from exceeding set-point temperatures. TRPC4 may represent a potential therapeutic target for managing Tcore.
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Affiliation(s)
- Qian Zhou
- School of Life Science and Technology, Shanghai Clinical Research and Trial Center, Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai 201210, China; Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xin Fu
- School of Life Science and Technology, Shanghai Clinical Research and Trial Center, Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai 201210, China; Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jianhui Xu
- Thermoregulation and Inflammation Laboratory, Chengdu Medical College, Chengdu, Sichuan 610500, China
| | - Shiming Dong
- University of Chinese Academy of Sciences, Beijing 100049, China; Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences (CAS), Shanghai 200031, China
| | - Changhao Liu
- School of Life Science and Technology, Shanghai Clinical Research and Trial Center, Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai 201210, China
| | - Dali Cheng
- Department of Electronic Engineering, Tsinghua University, Beijing 100084, China
| | - Cuicui Gao
- School of Life Science and Technology, Shanghai Clinical Research and Trial Center, Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai 201210, China; Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Minhua Huang
- Department of Biophysics, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Zhiduo Liu
- University of Chinese Academy of Sciences, Beijing 100049, China; State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Xinyan Ni
- School of Life Science and Technology, Shanghai Clinical Research and Trial Center, Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai 201210, China
| | - Rong Hua
- Department of General Surgery, Huashan Hospital, Fudan University, Shanghai 200433, China
| | - Hongqing Tu
- School of Life Science and Technology, Shanghai Clinical Research and Trial Center, Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai 201210, China
| | - Hongbin Sun
- School of Life Science and Technology, Shanghai Clinical Research and Trial Center, Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai 201210, China
| | - Qiwei Shen
- Department of General Surgery, Huashan Hospital, Fudan University, Shanghai 200433, China
| | - Baoting Chen
- School of Life Science and Technology, Shanghai Clinical Research and Trial Center, Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai 201210, China; Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jin Zhang
- School of Basic Medical Sciences, Nanchang University, Nanchang 330031, China
| | - Liye Zhang
- School of Life Science and Technology, Shanghai Clinical Research and Trial Center, Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai 201210, China
| | - Haitao Yang
- School of Life Science and Technology, Shanghai Clinical Research and Trial Center, Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai 201210, China
| | - Ji Hu
- School of Life Science and Technology, Shanghai Clinical Research and Trial Center, Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai 201210, China
| | - Wei Yang
- Department of Biophysics, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Weihua Pei
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Qiyuan Yao
- Department of General Surgery, Huashan Hospital, Fudan University, Shanghai 200433, China
| | - Xing Sheng
- Department of Electronic Engineering, Tsinghua University, Beijing 100084, China
| | - Jie Zhang
- Thermoregulation and Inflammation Laboratory, Chengdu Medical College, Chengdu, Sichuan 610500, China.
| | - Wen Z Yang
- School of Life Science and Technology, Shanghai Clinical Research and Trial Center, Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai 201210, China.
| | - Wei L Shen
- School of Life Science and Technology, Shanghai Clinical Research and Trial Center, Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai 201210, China.
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Ramirez MF, Guerra-Londono JJ, Owusu-Agyemang P, Fournier K, Guerra-Londono CE. Temperature management during cytoreductive surgery with hyperthermic intraperitoneal chemotherapy. Front Oncol 2023; 12:1062158. [PMID: 36741691 PMCID: PMC9894316 DOI: 10.3389/fonc.2022.1062158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 12/30/2022] [Indexed: 01/20/2023] Open
Abstract
In addition to attaining complete or near complete cytoreduction, the instillation of select heated chemotherapeutic agents into the abdominal cavity has offered a chance for cure or longer survival inpatients with peritoneal surface malignancies. While the heating of chemotherapeutic agents enhances cytotoxicity, the resulting systemic hyperthermia has been associated with an increased risk of severe hyperthermia and its associated complications. Factors that have been associated with an increased risk of severe hyperthermia include intraoperative blood transfusions and longer perfusion duration. However, the development of severe hyperthermia still remains largely unpredictable. Thus, at several institutions, cooling protocols are employed during cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC). Cooling protocols for CRS-HIPEC are not standardized and may be associated with episodes of severe hyperthermia or alternatively hypothermia. In theory, excessive cooling could result in a decreased effectiveness of the intraperitoneal chemotherapeutic agents. This presumption has been supported by a recent study of 214 adults undergoing CRS-HIPEC, where failure to attain a temperature of 38° C at the end of chemo-perfusion was associated with worse survival. Although not statistically significant, failure to maintain a temperature of 38° C for at least 30 minutes was associated with worse survival. Although studies are limited in this regard, the importance of maintaining a steady state of temperature during the hyperthermic phase of intraperitoneal chemotherapy administration cannot be disregarded. The following article describes the processes and physiological mechanisms responsible for hyperthermia during CRS-HIPEC. The challenges associated with temperature management during CRS-HIPEC and methods to avoid severe hypothermia and hyperthermia are also described.
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Affiliation(s)
- Maria F. Ramirez
- Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, United States,*Correspondence: Maria F. Ramirez,
| | - Juan Jose Guerra-Londono
- Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Pascal Owusu-Agyemang
- Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Keith Fournier
- Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Carlos E. Guerra-Londono
- Department of Anesthesiology, Pain Management, & Perioperative Medicine, Henry Ford Health System, Detroit, MI, United States
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Siwicka-Gieroba D, Robba C, Gołacki J, Badenes R, Dabrowski W. Cerebral Oxygen Delivery and Consumption in Brain-Injured Patients. J Pers Med 2022; 12:1763. [PMID: 36573716 PMCID: PMC9698645 DOI: 10.3390/jpm12111763] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 10/12/2022] [Accepted: 10/17/2022] [Indexed: 12/30/2022] Open
Abstract
Organism survival depends on oxygen delivery and utilization to maintain the balance of energy and toxic oxidants production. This regulation is crucial to the brain, especially after acute injuries. Secondary insults after brain damage may include impaired cerebral metabolism, ischemia, intracranial hypertension and oxygen concentration disturbances such as hypoxia or hyperoxia. Recent data highlight the important role of clinical protocols in improving oxygen delivery and resulting in lower mortality in brain-injured patients. Clinical protocols guide the rules for oxygen supplementation based on physiological processes such as elevation of oxygen supply (by mean arterial pressure (MAP) and intracranial pressure (ICP) modulation, cerebral vasoreactivity, oxygen capacity) and reduction of oxygen demand (by pharmacological sedation and coma or hypothermia). The aim of this review is to discuss oxygen metabolism in the brain under different conditions.
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Affiliation(s)
- Dorota Siwicka-Gieroba
- Department of Anaesthesiology and Intensive Care, Medical University in Lublin, 20-954 Lublin, Poland
| | - Chiara Robba
- Department of Anesthesiology and Intensive Care, San Martino Policlinico Hospital, IRCCS for Oncology and Neurosciences, 16132 Genoa, Italy
- Department of Surgical Sciences and Integrated Diagnostics (DISC), University of Genoa, 16132 Genoa, Italy
| | - Jakub Gołacki
- Department of Anaesthesiology and Intensive Care, Medical University in Lublin, 20-954 Lublin, Poland
| | - Rafael Badenes
- Department of Anesthesiology and Surgical-Trauma Intensive Care, Hospital Clinic Universitari, University of Valencia, 46010 Valencia, Spain
| | - Wojciech Dabrowski
- Department of Anaesthesiology and Intensive Care, Medical University in Lublin, 20-954 Lublin, Poland
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Brugaletta G, Greene E, Ramser A, Maynard CW, Tabler TW, Sirri F, Anthony NB, Orlowski S, Dridi S. Effect of Cyclic Heat Stress on Hypothalamic Oxygen Homeostasis and Inflammatory State in the Jungle Fowl and Three Broiler-Based Research Lines. Front Vet Sci 2022; 9:905225. [PMID: 35692291 PMCID: PMC9174949 DOI: 10.3389/fvets.2022.905225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Accepted: 04/20/2022] [Indexed: 11/23/2022] Open
Abstract
Heat stress (HS) is devastating to poultry production sustainability due its detrimental effects on performance, welfare, meat quality, and profitability. One of the most known negative effects of HS is feed intake depression, which is more pronounced in modern high-performing broilers compared to their ancestor unselected birds, yet the underlying molecular mechanisms are not fully defined. The present study aimed, therefore, to determine the hypothalamic expression of a newly involved pathway, hypoxia/oxygen homeostasis, in heat-stressed broiler-based research lines and jungle fowl. Three populations of broilers (slow growing ACRB developed in 1956, moderate growing 95RB from broilers available in 1995, and modern fast growing MRB from 2015) and unselected Jungle fowl birds were exposed to cyclic heat stress (36°C, 9 h/day for 4 weeks) in a 2 × 4 factorial experimental design. Total RNAs and proteins were extracted from the hypothalamic tissues and the expression of target genes and proteins was determined by real-time quantitative PCR and Western blot, respectively. It has been previously shown that HS increased core body temperature and decreased feed intake in 95RB and MRB, but not in ACRB or JF. HS exposure did not affect the hypothalamic expression of HIF complex, however there was a line effect for HIF-1α (P = 0.02) with higher expression in JF under heat stress. HS significantly up regulated the hypothalamic expression of hemoglobin subunits (HBA1, HBBR, HBE, HBZ), and HJV in ACRB, HBA1 and HJV in 95RB and MRB, and HJV in JF, but it down regulated FPN1 in JF. Additionally, HS altered the hypothalamic expression of oxygen homeostasis- up and down-stream signaling cascades. Phospho-AMPKThr172 was activated by HS in JF hypothalamus, but it decreased in that of the broiler-based research lines. Under thermoneutral conditions, p-AMPKThr172 was higher in broiler-based research lines compared to JF. Ribosomal protein S6K1, however, was significantly upregulated in 95RB and MRB under both environmental conditions. HS significantly upregulated the hypothalamic expression of NF-κB2 in MRB, RelB, and TNFα in ACRB, abut it down regulated RelA in 95RB. The regulation of HSPs by HS seems to be family- and line-dependent. HS upregulated the hypothalamic expression of HSP60 in ACRB and 95RB, down regulated HSP90 in JF only, and decreased HSP70 in all studied lines. Taken together, this is the first report showing that HS modulated the hypothalamic expression of hypoxia- and oxygen homeostasis-associated genes as well as their up- and down-stream mediators in chickens, and suggests that hypoxia, thermotolerance, and feed intake are interconnected, which merit further in-depth investigations.
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Affiliation(s)
- Giorgio Brugaletta
- Department of Poultry Science, Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR, United States
- Department of Agricultural and Food Sciences, Alma Mater Studiorum – University of Bologna, Bologna, Italy
| | - Elizabeth Greene
- Department of Poultry Science, Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR, United States
| | - Alison Ramser
- Department of Poultry Science, Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR, United States
| | - Craig W. Maynard
- Department of Poultry Science, Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR, United States
| | - Travis W. Tabler
- Department of Poultry Science, Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR, United States
| | - Federico Sirri
- Department of Agricultural and Food Sciences, Alma Mater Studiorum – University of Bologna, Bologna, Italy
| | - Nicholas B. Anthony
- Department of Poultry Science, Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR, United States
| | - Sara Orlowski
- Department of Poultry Science, Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR, United States
| | - Sami Dridi
- Department of Poultry Science, Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR, United States
- *Correspondence: Sami Dridi
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Abstract
This paper presents the findings of a 6-week long, five-participant experiment in a controlled climate chamber. The experiment was designed to understand the effect of time on thermal behaviour, electrodermal activity (EDA) and the adaptive behavior of occupants in response to a thermal non-uniform indoor environment were continuously logged. The results of the 150 h-long longitudinal study suggested a significant difference in tonic EDA levels between “morning” and “afternoon” clusters although the environmental parameters were the same, suggesting a change in the human body’s thermal reception over time. The correlation of the EDA and temperature was greater for the afternoon cluster (r = 0.449, p < 0.001) in relation to the morning cluster (r = 0.332, p < 0.001). These findings showed a strong temporal dependency of the skin conductance level of the EDA to the operative temperature, following the person’s circadian rhythm. Even further, based on the person’s chronotype, the beginning of the “afternoon” cluster was observed to have shifted according to the person’s circadian rhythm. Furthermore, the study is able to show how the body reacts differently under the same PMV values, both within and between subjects; pointing to the lack of temporal parameter in the PMV model.
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Shevelev O, Petrova M, Smolensky A, Osmonov B, Toimatov S, Kharybina T, Karbainov S, Ovchinnikov L, Vesnin S, Tarakanov A, Goryanin I. Using medical microwave radiometry for brain temperature measurements. Drug Discov Today 2021; 27:881-889. [PMID: 34767961 DOI: 10.1016/j.drudis.2021.11.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Revised: 09/29/2021] [Accepted: 11/02/2021] [Indexed: 11/30/2022]
Abstract
Brain temperature (BT) is a crucial physiological parameter used to monitor cerebral status. Physical activities and traumatic brain injuries (TBI) can affect BT; therefore, non-invasive BT monitoring is an important way to gain insight into TBI, stroke, and wellbeing. The effects of BT on physical performance have been studied at length. When humans are under extreme conditions, most of the energy consumed is used to maintain the BT. In addition, measuring the BT is useful for early brain diagnostics. Passive microwave radiometry (MWR) measures the intrinsic radiation of tissues in the 1-4 GHz range. It was shown that non-invasive passive MWR technology can successfully measure BT and identify even small TBIs. Here, we review the potential applications of MWR for assessing BT.
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Affiliation(s)
- Oleg Shevelev
- People' Friendship University of Russia, Moscow, Russia; Federal Research and Clinical Centre for Resuscitation and Rehabilitation, Moscow, Russia
| | - Marina Petrova
- People' Friendship University of Russia, Moscow, Russia; Federal Research and Clinical Centre for Resuscitation and Rehabilitation, Moscow, Russia
| | - Andrey Smolensky
- Russian State University of Physical Culture, Sports, Youth and Tourism, Moscow, Russia
| | - Batyr Osmonov
- Educational - Scientifc Medical Center of Kyrgyz Medical Sate University, Bishkek, Kyrgyz Republic
| | | | - Tatyana Kharybina
- Library for Natural Sciences of the Russian Academy of Sciences, Moscow, Russia
| | | | | | - Sergey Vesnin
- Medical Microwave Radiometry Ltd, Edinburgh, UK; RTM Diagnostic LLC, Moscow, Russia; Bauman Moscow State Technical University, Moscow, Russia
| | | | - Igor Goryanin
- School of Informatics, University of Edinburgh, Edinburgh, UK; Institute Theoretical and Experimental Biophysics, Pushchino, Russia; Okinawa Institute Science and Technology, Okinawa, Japan.
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Becker BE. Case report: The physiology of a preventable tragedy -Near death in a hot tub. Clin Case Rep 2021; 9:e04951. [PMID: 34745615 PMCID: PMC8548817 DOI: 10.1002/ccr3.4951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 08/19/2021] [Accepted: 08/26/2021] [Indexed: 11/08/2022] Open
Abstract
Hyperthermia in children is a known risk within enclosed vehicles. Exposure to an overheated hot tub poses a real risk in children due to unique pediatric physiology. Medical and aquatic professionals should understand the risk and mitigation strategies.
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Millet J, Siracusa J, Tardo-Dino PE, Thivel D, Koulmann N, Malgoyre A, Charlot K. Effects of Acute Heat and Cold Exposures at Rest or during Exercise on Subsequent Energy Intake: A Systematic Review and Meta-Analysis. Nutrients 2021; 13:nu13103424. [PMID: 34684424 PMCID: PMC8538265 DOI: 10.3390/nu13103424] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 09/25/2021] [Accepted: 09/27/2021] [Indexed: 02/06/2023] Open
Abstract
The objective of this meta-analysis was to assess the effect of acute heat/cold exposure on subsequent energy intake (EI) in adults. We searched the following sources for publications on this topic: PubMed, Ovid Medline, Science Direct and SPORTDiscus. The eligibility criteria for study selection were: randomized controlled trials performed in adults (169 men and 30 women; 20–52 years old) comparing EI at one or more meals taken ad libitum, during and/or after exposure to heat/cold and thermoneutral conditions. One of several exercise sessions could be realized before or during thermal exposures. Two of the thirteen studies included examined the effect of heat (one during exercise and one during exercise and at rest), eight investigated the effect of cold (six during exercise and two at rest), and three the effect of both heat and cold (two during exercise and one at rest). The meta-analysis revealed a small increase in EI in cold conditions (g = 0.44; p = 0.019) and a small decrease in hot conditions (g = −0.39, p = 0.022) for exposure during both rest and exercise. Exposures to heat and cold altered EI in opposite ways, with heat decreasing EI and cold increasing it. The effect of exercise remains unclear.
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Affiliation(s)
- Juliette Millet
- Département Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Unité de Physiologie des Exercices et Activités en Conditions Extrêmes, 91223 Bretigny-Sur-Orge, France; (J.M.); (J.S.); (P.-E.T.-D.); (N.K.); (A.M.)
- LBEPS, Univ Evry, IRBA, Université Paris Saclay, 91025 Evry, France
| | - Julien Siracusa
- Département Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Unité de Physiologie des Exercices et Activités en Conditions Extrêmes, 91223 Bretigny-Sur-Orge, France; (J.M.); (J.S.); (P.-E.T.-D.); (N.K.); (A.M.)
- LBEPS, Univ Evry, IRBA, Université Paris Saclay, 91025 Evry, France
| | - Pierre-Emmanuel Tardo-Dino
- Département Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Unité de Physiologie des Exercices et Activités en Conditions Extrêmes, 91223 Bretigny-Sur-Orge, France; (J.M.); (J.S.); (P.-E.T.-D.); (N.K.); (A.M.)
- LBEPS, Univ Evry, IRBA, Université Paris Saclay, 91025 Evry, France
| | - David Thivel
- Laboratory AME2P, University of Clermont Auvergne, 63170 Aubière, France;
| | - Nathalie Koulmann
- Département Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Unité de Physiologie des Exercices et Activités en Conditions Extrêmes, 91223 Bretigny-Sur-Orge, France; (J.M.); (J.S.); (P.-E.T.-D.); (N.K.); (A.M.)
- LBEPS, Univ Evry, IRBA, Université Paris Saclay, 91025 Evry, France
- Ecole du Val-de-Grâce, 1, Place Alphonse Laveran, 75230 Paris, France
| | - Alexandra Malgoyre
- Département Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Unité de Physiologie des Exercices et Activités en Conditions Extrêmes, 91223 Bretigny-Sur-Orge, France; (J.M.); (J.S.); (P.-E.T.-D.); (N.K.); (A.M.)
- LBEPS, Univ Evry, IRBA, Université Paris Saclay, 91025 Evry, France
| | - Keyne Charlot
- Département Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Unité de Physiologie des Exercices et Activités en Conditions Extrêmes, 91223 Bretigny-Sur-Orge, France; (J.M.); (J.S.); (P.-E.T.-D.); (N.K.); (A.M.)
- LBEPS, Univ Evry, IRBA, Université Paris Saclay, 91025 Evry, France
- Correspondence: ; Tel.: +33-(1)78-65-13-03
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11
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Sahib S, Sharma A, Muresanu DF, Zhang Z, Li C, Tian ZR, Buzoianu AD, Lafuente JV, Castellani RJ, Nozari A, Patnaik R, Menon PK, Wiklund L, Sharma HS. Nanodelivery of traditional Chinese Gingko Biloba extract EGb-761 and bilobalide BN-52021 induces superior neuroprotective effects on pathophysiology of heat stroke. PROGRESS IN BRAIN RESEARCH 2021; 265:249-315. [PMID: 34560923 DOI: 10.1016/bs.pbr.2021.06.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Military personnel often exposed to high summer heat are vulnerable to heat stroke (HS) resulting in abnormal brain function and mental anomalies. There are reasons to believe that leakage of the blood-brain barrier (BBB) due to hyperthermia and development of brain edema could result in brain pathology. Thus, exploration of suitable therapeutic strategies is needed to induce neuroprotection in HS. Extracts of Gingko Biloba (EGb-761) is traditionally used in a variety of mental disorders in Chinese traditional medicine since ages. In this chapter, effects of TiO2 nanowired EGb-761 and BN-52021 delivery to treat brain pathologies in HS is discussed based on our own investigations. We observed that TiO2 nanowired delivery of EGb-761 or TiO2 BN-52021 is able to attenuate more that 80% reduction in the brain pathology in HS as compared to conventional drug delivery. The functional outcome after HS is also significantly improved by nanowired delivery of EGb-761 and BN-52021. These observations are the first to suggest that nanowired delivery of EGb-761 and BN-52021 has superior therapeutic effects in HS not reported earlier. The clinical significance in relation to the military medicine is discussed.
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Affiliation(s)
- Seaab Sahib
- Department of Chemistry & Biochemistry, University of Arkansas, Fayetteville, AR, United States
| | - Aruna Sharma
- International Experimental Central Nervous System Injury & Repair (IECNSIR), Department of Surgical Sciences, Anesthesiology & Intensive Care Medicine, Uppsala University Hospital, Uppsala University, Uppsala, Sweden.
| | - Dafin F Muresanu
- Department of Clinical Neurosciences, University of Medicine & Pharmacy, Cluj-Napoca, Romania; "RoNeuro" Institute for Neurological Research and Diagnostic, Cluj-Napoca, Romania
| | - Zhiqiang Zhang
- Department of Neurosurgery, Chinese Medicine Hospital of Guangdong Province, The Second Affiliated Hospital, Guangzhou University of Chinese Medicine, Yuexiu, Guangzhou, China
| | - Cong Li
- Department of Neurosurgery, Chinese Medicine Hospital of Guangdong Province, The Second Affiliated Hospital, Guangzhou University of Chinese Medicine, Yuexiu, Guangzhou, China
| | - Z Ryan Tian
- Department of Chemistry & Biochemistry, University of Arkansas, Fayetteville, AR, United States
| | - Anca D Buzoianu
- Department of Clinical Pharmacology and Toxicology, "Iuliu Hatieganu" University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - José Vicente Lafuente
- LaNCE, Department of Neuroscience, University of the Basque Country (UPV/EHU), Leioa, Bizkaia, Spain
| | - Rudy J Castellani
- Department of Pathology, University of Maryland, Baltimore, MD, United States
| | - Ala Nozari
- Anesthesiology & Intensive Care, Massachusetts General Hospital, Boston, MA, United States
| | - Ranjana Patnaik
- Department of Biomaterials, School of Biomedical Engineering, Indian Institute of Technology, Banaras Hindu University, Varanasi, India
| | - Preeti K Menon
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Lars Wiklund
- International Experimental Central Nervous System Injury & Repair (IECNSIR), Department of Surgical Sciences, Anesthesiology & Intensive Care Medicine, Uppsala University Hospital, Uppsala University, Uppsala, Sweden
| | - Hari Shanker Sharma
- International Experimental Central Nervous System Injury & Repair (IECNSIR), Department of Surgical Sciences, Anesthesiology & Intensive Care Medicine, Uppsala University Hospital, Uppsala University, Uppsala, Sweden.
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12
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Effects of passive heat stress and recovery on human cognitive function: An ERP study. PLoS One 2021; 16:e0254769. [PMID: 34283865 PMCID: PMC8291678 DOI: 10.1371/journal.pone.0254769] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 07/02/2021] [Indexed: 11/19/2022] Open
Abstract
Using event-related potentials (ERPs), we investigated the effects of passive heat stress and recovery on the human cognitive function with Flanker tasks, involving congruent and incongruent stimuli. We hypothesized that modulation of the peak amplitude and latency of the P300 component in ERP waveforms would differ with task difficulty during passive heat stress and recovery. Subjects performed the Flanker tasks before (Pre), at the end of whole body heating (Heat: internal temperature increase of ~1.2°C from the pre-heat baseline), and after the internal temperature had returned to the pre-heat baseline (Recovery). The internal temperature was regulated by a tube-lined suit by perfusing 50°C water for heat stress and 25°C water for recovery immediately after the heat stress. Regardless of task difficulty, the reaction time (RT) was shortened during Heat rather than Pre and Recovery, and standard deviations of RT (i.e., response variability) were significantly smaller during Heat than Pre. However, the peak amplitudes of the P300 component in ERPs, which involved selective attention, expectancy, and memory updating, were significantly smaller during Heat than during Pre, suggesting the impairment of neural activity in cognitive function. Notably, the peak amplitudes of the P300 component were higher during Recovery than during Heat, indicating that the impaired neural activity had recovered after sufficient whole-body cooling. An indicator of the stimulus classification/evaluation time (peak latency of P300) and the RT were shortened during Heat stress, but such shortening was not noted after whole-body cooling. These results suggest that hyperthermia affects the human cognitive function, reflected by the peak amplitude and latency of the P300 component in ERPs during the Flanker tasks, but sufficient treatment such as whole-body cooling performed in this study can recover those functions.
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13
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Rass V, Huber L, Ianosi BA, Kofler M, Lindner A, Picetti E, Ortolano F, Beer R, Rossi S, Smielewski P, Stocchetti N, Helbok R. The Effect of Temperature Increases on Brain Tissue Oxygen Tension in Patients with Traumatic Brain Injury: A Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury Substudy. Ther Hypothermia Temp Manag 2020; 11:122-131. [PMID: 33202157 DOI: 10.1089/ther.2020.0027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Fever may aggravate secondary brain injury after traumatic brain injury (TBI). The aim of this study was to identify episodes of temperature increases through visual plot analysis and algorithm supported detection, and to describe associated patterns of changes in on brain tissue oxygen tension (PbtO2). Data derive from the high-resolution cohort of the multicenter prospective Collaborative European NeuroTrauma Effectiveness Research in TBI (CENTER-TBI) study. Temperature increases (≥0.5°C) were visually identified in 33 patients within the first 11 days of monitoring. Generalized estimating equations were used to detect significant changes of systemic and neuromonitoring parameters from baseline to the highest temperature. Patients were median 50 (interquartile range [IQR], 35-62) years old, and presented with a Glasgow Coma Scale (GCS) of 8 (IQR, 4-10). In 202 episodes of temperature increases, mean temperature rose by 1.0°C ± 0.5°C within 4 hours. Overall, PbtO2 slightly increased (ΔPbtO2 = 0.9 ± 6.1 mmHg, p = 0.022) during temperature increases. PbtO2 increased in 35% (p < 0.001), was stable in 49% (p = 0.852), and decreased in 16% (p < 0.001) of episodes. During episodes of temperature increases and simultaneous drops in PbtO2, cerebral perfusion pressure (CPP) decreased (ΔCPP -6.3 ± 11.5 mmHg; p < 0.001). Brain tissue hypoxia (PbtO2 <20 mmHg) developed during 27/164 (17%) episodes of effervescences, in the remaining 38/202 episodes baseline PbtO2 was already <20 mmHg. Comparable results were found when using algorithm-supported detection of temperature increases. In conclusion, during effervescences, PbtO2 was mostly stable or slightly increased. A decrease of PbtO2 was observed in every sixth episode, where it was associated with a decrease in CPP. Our data highlight the need for special attention to CPP monitoring and maintenance during episodes of fever.
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Affiliation(s)
- Verena Rass
- Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
| | - Lukas Huber
- Institute of Medical Informatics, UMIT: University for Health Sciences, Medical Informatics and Technology, Hall, Austria
| | - Bogdan-Andrei Ianosi
- Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria.,Institute of Medical Informatics, UMIT: University for Health Sciences, Medical Informatics and Technology, Hall, Austria
| | - Mario Kofler
- Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
| | - Anna Lindner
- Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
| | - Edoardo Picetti
- Department of Anesthesia and Intensive Care, Parma University Hospital, Parma, Italy
| | - Fabrizio Ortolano
- Neuroscience Intensive Care Unit, Department of Anesthesia and Critical Care, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Ronny Beer
- Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
| | - Sandra Rossi
- Department of Anesthesia and Intensive Care, Parma University Hospital, Parma, Italy
| | - Peter Smielewski
- Brain Physics Laboratory, Division of Neurosurgery, Addenbrooke's Hospital, Cambridge University Hospital NHS Foundation Trust, Cambridge, United Kingdom
| | - Nino Stocchetti
- Neuroscience Intensive Care Unit, Department of Anesthesia and Critical Care, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milan, Italy.,Department of Pathophysiology and Transplants, University of Milan, Milan, Italy
| | - Raimund Helbok
- Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
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14
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Shibasaki M, Sato K, Hirasawa A, Sadamoto T, Crandall CG, Ogoh S. An assessment of hypercapnia-induced elevations in regional cerebral perfusion during combined orthostatic and heat stresses. J Physiol Sci 2020; 70:25. [PMID: 32366213 PMCID: PMC8006159 DOI: 10.1186/s12576-020-00751-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 04/23/2020] [Indexed: 11/10/2022]
Abstract
We investigated that the effects of hypercapnia-induced elevations in cerebral perfusion during a heat stress on global cerebrovascular responses to an orthostatic challenge. Seven volunteers completed a progressive lower-body negative pressure (LBNP) challenge to presyncope during heat stress, with or without breathing a hypercapnic gas mixture. Administration of the hypercapnic gas mixture increased the partial pressure of end-tidal CO2 greater than pre-heat stress alone, and increased both internal carotid artery (ICA) and vertebral artery (VA) blood flows (P < 0.05). During LBNP, both ICA and VA blood flows with the hypercapnic gas mixture remained elevated relative to the control trial (P < 0.05). However, at the end of LBNP due to pre-syncopal symptoms, both ICA and VA blood flows decreased to similar levels between trials. These findings suggest that hypercapnia-induced cerebral vasodilation is insufficient to maintain cerebral perfusion at the end of LBNP due to pre-syncope in either the anterior or posterior vascular beds.
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Affiliation(s)
- Manabu Shibasaki
- Department of Health Sciences, Faculty of Human Life and Environment, Nara Women's University, Kitauoya-Nishi Machi, Nara, 630-8506, Japan.
| | - Kohei Sato
- Department of Health and Physical Education, Tokyo Gakugei University, Tokyo, Japan
| | - Ai Hirasawa
- Department of Health and Welfare, Kyorin University, Tokyo, Japan
| | - Tomoko Sadamoto
- Research Institute of Physical Fitness, Japan Women's College of Physical Education, Tokyo, Japan
| | - Craig G Crandall
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, USA.,Department of Internal Medicine, University of Texas, Southwestern Medical Center, Dallas, USA
| | - Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, Saitama, Japan
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15
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Rivas E, Allie KN, Salvador PM. Progressive dry to humid hyperthermia alters exercise cerebral blood flow. J Therm Biol 2019; 84:398-406. [PMID: 31466779 DOI: 10.1016/j.jtherbio.2019.07.036] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 07/27/2019] [Accepted: 07/29/2019] [Indexed: 11/27/2022]
Abstract
INTRODUCTION Exercising in hot conditions may increase the risk for exertional heat-related illness due to reduction in cerebral blood flow (CBF); however, the acute effect of exercise-induced changes on CBF during compensable and uncompensable heat stress remain unclear. We tested the hypothesis that exercising in hot dry and humid conditions would have different CBF responses. METHODS Nine healthy active males completed a 30 min baseline rest then 60 min of low intensity self-paced exercise (12 rating of perceived exertion) in a 1) control compensable neutral dry (CN; 23.7 ± 0.7 °C; 10.7 ± 0.8%Rh) and 2) compensable hot dry (CH; 42.3 ± 0.3 °C; 10.7 ± 1.8%Rh) that progressively increased to an uncompensable hot humid (UCH; 42.3 ± 0.3 °C; 55.2 ± 7.7%Rh) environment in random order separated by at least 4 days. RESULTS We observed that during CN environments from rest through 60 min of exercise, middle cerebral velocity (MCAvmean) and conductance (MCAvmean CVC) remained unchanged. In contrast, during CH, MCAvmean, MCAvmean CVC, and cardiac output (Q) increased and systemic vascular resistance (SVR) decreased. However, under UCH, MCAvmean, MCAvmean CVC, and Q was reduced. No difference in mean arterial pressure or ventilation was observed during any condition. Only during UCH, end-tidal PO2 increased and PCO2 decreased. The redistribution of blood to the skin for thermoregulation (heart rate, skin blood flow and sweat rate) remained higher during exercise in UCH environments. CONCLUSIONS Collectively, exercise cerebral blood flow is altered by an integrative physiological manner that differs in CN, CH, and UCH environments. The control of CBF may be secondary to thermoregulatory control which may provide an explanation for the cause of exertional heat illness.
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Affiliation(s)
- Eric Rivas
- Exercise & Thermal Integrative Physiology Laboratory, Texas Tech University, Lubbock, TX, USA; Department of Kinesiology & Sport Management, Texas Tech University, Lubbock, TX, USA.
| | - Kyleigh N Allie
- Exercise & Thermal Integrative Physiology Laboratory, Texas Tech University, Lubbock, TX, USA; Department of Kinesiology & Sport Management, Texas Tech University, Lubbock, TX, USA
| | - Paolo M Salvador
- Exercise & Thermal Integrative Physiology Laboratory, Texas Tech University, Lubbock, TX, USA; Department of Kinesiology & Sport Management, Texas Tech University, Lubbock, TX, USA
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16
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Qin X, Cheng J, Zhong Y, Mahgoub OK, Akter F, Fan Y, Aldughaim M, Xie Q, Qin L, Gu L, Jian Z, Xiong X, Liu R. Mechanism and Treatment Related to Oxidative Stress in Neonatal Hypoxic-Ischemic Encephalopathy. Front Mol Neurosci 2019; 12:88. [PMID: 31031592 PMCID: PMC6470360 DOI: 10.3389/fnmol.2019.00088] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 03/21/2019] [Indexed: 12/24/2022] Open
Abstract
Hypoxic ischemic encephalopathy (HIE) is a type of neonatal brain injury, which occurs due to lack of supply and oxygen deprivation to the brain. It is associated with a high morbidity and mortality rate. There are several therapeutic strategies that can be used to improve outcomes in patients with HIE. These include cell therapies such as marrow mesenchymal stem cells (MSCs) and umbilical cord blood stem cells (UCBCs), which are being incorporated into the new protocols for the prevention of ischemic brain damage. The focus of this review is to discuss the mechanism of oxidative stress in HIE and summarize the current available treatments for HIE. We hope that a better understanding of the relationship between oxidative stress and HIE will provide new insights on the potential therapy of this devastating condition.
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Affiliation(s)
- Xingping Qin
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, China.,Department of Neurosurgery, Harvard Medical School, Boston, MA, United States
| | - Jing Cheng
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yi Zhong
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Omer Kamal Mahgoub
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Farhana Akter
- Department of Neurosurgery, Harvard Medical School, Boston, MA, United States.,Department of Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Yanqin Fan
- Central Laboratory, Renmin Hospital of Wuhan University, Wuhan, China
| | - Mohammed Aldughaim
- Department of Neurosurgery, Harvard Medical School, Boston, MA, United States
| | - Qiurong Xie
- Department of Gynecology and Obstetrics, Renmin Hospital of Wuhan University, Wuhan, China
| | - Lingxia Qin
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Lijuan Gu
- Central Laboratory, Renmin Hospital of Wuhan University, Wuhan, China
| | - Zhihong Jian
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Xiaoxing Xiong
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Renzhong Liu
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, China
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17
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Fujii N, Kashihara M, Kenny GP, Honda Y, Fujimoto T, Cao Y, Nishiyasu T. Carotid chemoreceptors have a limited role in mediating the hyperthermia-induced hyperventilation in exercising humans. J Appl Physiol (1985) 2019; 126:305-313. [PMID: 30382804 DOI: 10.1152/japplphysiol.00562.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Hyperthermia causes hyperventilation at rest and during exercise. We previously reported that carotid chemoreceptors partly contribute to the hyperthermia-induced hyperventilation at rest. However, given that a hyperthermia-induced hyperventilation markedly differs between rest and exercise, the results obtained at rest may not be representative of the response in exercise. Therefore, we evaluated whether carotid chemoreceptors contribute to hyperthermia-induced hyperventilation in exercising humans. Eleven healthy young men (23 ± 2 yr) cycled in the heat (37°C) at a fixed submaximal workload equal to ~55% of the individual's predetermined peak oxygen uptake (moderate intensity). To suppress carotid chemoreceptor activity, 30-s hyperoxia breathing (100% O2) was performed at rest (before exercise) and during exercise at increasing levels of hyperthermia as defined by an increase in esophageal temperature of 0.5°C (low), 1.0°C (moderate), 1.5°C (high), and 2.0°C (severe) above resting levels. Ventilation during exercise gradually increased as esophageal temperature increased (all P ≤ 0.05), indicating that hyperthermia-induced hyperventilation occurred. Hyperoxia breathing suppressed ventilation in a greater manner during exercise (-9 to -13 l/min) than at rest (-2 ± 1 l/min); however, the magnitude of reduction during exercise did not differ at low (0.5°C) to severe (2.0°C) increases in esophageal temperature (all P > 0.05). Similarly, hyperoxia-induced changes in ventilation during exercise as assessed by percent change from prehyperoxic levels were not different at all levels of hyperthermia (~15-20%, all P > 0.05). We show that in young men carotid chemoreceptor contribution to hyperthermia-induced hyperventilation is relatively small at low-to-severe increases in body core temperature induced by moderate-intensity exercise in the heat. NEW & NOTEWORTHY Exercise-induced increases in hyperthermia cause a progressive increase in ventilation in humans. However, the mechanisms underpinning this response remain unresolved. We showed that in young men hyperventilation associated with exercise-induced hyperthermia is not predominantly mediated by carotid chemoreceptors. This study provides important new insights into the mechanism(s) underpinning the regulation of hyperthermia-induced hyperventilation in humans and suggests that factor(s) other than carotid chemoreceptors play a more important role in mediating this response.
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Affiliation(s)
- Naoto Fujii
- Faculty of Health and Sport Sciences, University of Tsukuba , Tsukuba , Japan
| | - Miki Kashihara
- Faculty of Health and Sport Sciences, University of Tsukuba , Tsukuba , Japan
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, University of Ottawa , Ottawa Ontario , Canada
| | - Yasushi Honda
- Faculty of Health and Sport Sciences, University of Tsukuba , Tsukuba , Japan
| | - Tomomi Fujimoto
- Faculty of Health and Sport Sciences, University of Tsukuba , Tsukuba , Japan
| | - Yinhang Cao
- Faculty of Health and Sport Sciences, University of Tsukuba , Tsukuba , Japan
| | - Takeshi Nishiyasu
- Faculty of Health and Sport Sciences, University of Tsukuba , Tsukuba , Japan
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18
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Diehl JW, Hullsiek KH, Okirwoth M, Stephens N, Abassi M, Rhein J, Meya DB, Boulware DR, Musubire AK. Cerebral Oximetry for Detecting High-mortality Risk Patients with Cryptococcal Meningitis. Open Forum Infect Dis 2018; 5:ofy105. [PMID: 29942819 PMCID: PMC6007269 DOI: 10.1093/ofid/ofy105] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 05/07/2018] [Indexed: 11/13/2022] Open
Abstract
Background Cryptococcus is the commonest cause of adult meningitis in Africa, with 50%–70% experiencing increased intracranial pressure. Cerebral oximetry is a noninvasive near-infrared spectroscopy technology to monitor percent regional cerebral tissue oxygenation (rSO2). We assessed if cerebral oximetry predicts meningitis mortality. Methods We performed cerebral oximetry within 14 days of cryptococcal meningitis diagnosis on 121 Ugandans from April 2016 to September 2017. We evaluated baseline rSO2 association with mortality by multivariable logistic regression and correlation with other clinical factors. We compared groups formed by initial rSO2 <30% vs ≥30% for longitudinal change with mixed effects models. We measured change in %rSO2 before and after lumbar puncture (LP). Results The median initial rSO2 (interquartile range) was 36% (29%–42%), and it was <30% in 29% (35/121). For 30-day mortality, the unadjusted odds ratio (per 5% increase in rSO2) was 0.73 (95% confidence interval [CI], 0.58 to 0.91; P = .005). Those with initial rSO2 <30% had 3.4 (95% CI, 1.5 to 8.0) higher odds of 30-day mortality than those with initial rSO2 ≥30%. Hemoglobin correlated with initial rSO2 (rho = .54; P < .001), but rSO2 did not correlate with pulse oximetry, intracranial pressure, cerebral perfusion pressure, or quantitative cerebrospinal fluid culture, and rSO2 was unchanged pre/post–lumbar punctures. The longitudinal rSO2 measurements change was 15% (95% CI, 12% to 18%) lower in the group with initial rSO2 <30%. Conclusions Individuals with cryptococcal meningitis and low cerebral oximetry (rSO2 < 30%) have high mortality. Cerebral oximetry may be useful as a prognostic marker of mortality. Targeted interventions to improve rSO2 should be tested in trials to try to decrease mortality in meningitis.
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Affiliation(s)
- John W Diehl
- Infectious Disease Institute, Makerere University, Kampala, Uganda.,University of Minnesota, Minneapolis, Minnesota.,Emory University School of Medicine, Atlanta, Georgia
| | | | - Michael Okirwoth
- Infectious Disease Institute, Makerere University, Kampala, Uganda
| | | | - Mahsa Abassi
- Infectious Disease Institute, Makerere University, Kampala, Uganda.,University of Minnesota, Minneapolis, Minnesota
| | - Joshua Rhein
- Infectious Disease Institute, Makerere University, Kampala, Uganda.,University of Minnesota, Minneapolis, Minnesota
| | - David B Meya
- Infectious Disease Institute, Makerere University, Kampala, Uganda.,University of Minnesota, Minneapolis, Minnesota
| | | | - Abdu K Musubire
- Infectious Disease Institute, Makerere University, Kampala, Uganda.,University of Minnesota, Minneapolis, Minnesota
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Heinonen I, Laukkanen JA. Effects of heat and cold on health, with special reference to Finnish sauna bathing. Am J Physiol Regul Integr Comp Physiol 2018; 314:R629-R638. [DOI: 10.1152/ajpregu.00115.2017] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Environmental stress such as extremely warm or cold temperature is often considered a challenge to human health and body homeostasis. However, the human body can adapt relatively well to heat and cold environments, and recent studies have also elucidated that particularly heat stress might be even highly beneficial for human health. Consequently, the aim of the present brief review is first to discuss general cardiovascular and other responses to acute heat stress, followed by a review of beneficial effects of Finnish sauna bathing on general and cardiovascular health and mortality as well as dementia and Alzheimer's disease risk. Plausible mechanisms included are improved endothelial and microvascular function, reduced blood pressure and arterial stiffness, and possibly increased angiogenesis in humans, which are likely to mediate the health benefits of sauna bathing. In addition to heat exposure with physiological adaptations, cold stress-induced physiological responses and brown fat activation on health are also discussed. This is important to take into consideration, as sauna bathing is frequently associated with cooling periods in cold(er) environments, but their combination remains poorly investigated. We finally propose, therefore, that possible additive effects of heat- and cold-stress-induced adaptations and effects on health would be worthy of further investigation.
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Affiliation(s)
- Ilkka Heinonen
- Turku PET Centre, University of Turku, Turku, Finland
- Department of Clinical Physiology and Nuclear Medicine, University of Turku, Turku, Finland
- Division of Experimental Cardiology, Thoraxcenter, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Jari A. Laukkanen
- Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland
- Central Finland Health Care District, Jyväskylä, Finland
- Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
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20
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Tsuji B, Filingeri D, Honda Y, Eguchi T, Fujii N, Kondo N, Nishiyasu T. Effect of hypocapnia on the sensitivity of hyperthermic hyperventilation and the cerebrovascular response in resting heated humans. J Appl Physiol (1985) 2018; 124:225-233. [DOI: 10.1152/japplphysiol.00232.2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Elevating core temperature at rest causes increases in minute ventilation (V̇e), which lead to reductions in both arterial CO2 partial pressure (hypocapnia) and cerebral blood flow. We tested the hypothesis that in resting heated humans this hypocapnia diminishes the ventilatory sensitivity to rising core temperature but does not explain a large portion of the decrease in cerebral blood flow. Fourteen healthy men were passively heated using hot-water immersion (41°C) combined with a water-perfused suit, which caused esophageal temperature (Tes) to reach 39°C. During heating in two separate trials, end-tidal CO2 partial pressure decreased from the level before heating (39.4 ± 2.0 mmHg) to the end of heating (30.5 ± 6.3 mmHg) ( P = 0.005) in the Control trial. This decrease was prevented by breathing CO2-enriched air throughout the heating such that end-tidal CO2 partial pressure did not differ between the beginning (39.8 ± 1.5 mmHg) and end (40.9 ± 2.7 mmHg) of heating ( P = 1.00). The sensitivity to rising Tes (i.e., slope of the Tes − V̇E relation) did not differ between the Control and CO2-breathing trials (37.1 ± 43.1 vs. 16.5 ± 11.1 l·min−1·°C−1, P = 0.31). In both trials, middle cerebral artery blood velocity (MCAV) decreased early during heating (all P < 0.01), despite the absence of hyperventilation-induced hypocapnia. CO2 breathing increased MCAV relative to Control at the end of heating ( P = 0.005) and explained 36.6% of the heat-induced reduction in MCAV. These results indicate that during passive heating at rest ventilatory sensitivity to rising core temperature is not suppressed by hypocapnia and that most of the decrease in cerebral blood flow occurs independently of hypocapnia. NEW & NOTEWORTHY Hyperthermia causes hyperventilation and concomitant hypocapnia and cerebral hypoperfusion. The last may underlie central fatigue. We are the first to demonstrate that hyperthermia-induced hyperventilation is not suppressed by the resultant hypocapnia and that hypocapnia explains only 36% of cerebral hypoperfusion elicited by hyperthermia. These new findings advance our understanding of the mechanisms controlling ventilation and cerebral blood flow during heat stress, which may be useful for developing interventions aimed at preventing central fatigue during hyperthermia.
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Affiliation(s)
- Bun Tsuji
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba City, Ibaraki, Japan
- Department of Health Sciences, Prefectural University of Hiroshima, Hiroshima, Japan
| | - Davide Filingeri
- Environmental Ergonomics Research Centre, Loughborough Design School, Loughborough University, Loughborough, United Kingdom
| | - Yasushi Honda
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba City, Ibaraki, Japan
| | - Tsubasa Eguchi
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba City, Ibaraki, Japan
| | - Naoto Fujii
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba City, Ibaraki, Japan
| | - Narihiko Kondo
- Faculty of Human Development, Kobe University, Kobe, Japan
| | - Takeshi Nishiyasu
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba City, Ibaraki, Japan
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21
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Tan XR, Low ICC, Stephenson MC, Soong TW, Lee JKW. Neural basis of exertional fatigue in the heat: A review of magnetic resonance imaging methods. Scand J Med Sci Sports 2017; 28:807-818. [PMID: 29136305 DOI: 10.1111/sms.13015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/08/2017] [Indexed: 12/19/2022]
Abstract
The central nervous system, specifically the brain, is implicated in the development of exertional fatigue under a hot environment. Diverse neuroimaging techniques have been used to visualize the brain activity during or after exercise. Notably, the use of magnetic resonance imaging (MRI) has become prevalent due to its excellent spatial resolution and versatility. This review evaluates the significance and limitations of various brain MRI techniques in exercise studies-brain volumetric analysis, functional MRI, functional connectivity MRI, and arterial spin labeling. The review aims to provide a summary on the neural basis of exertional fatigue and proposes future directions for brain MRI studies. A systematic literature search was performed where a total of thirty-seven brain MRI studies associated with exercise, fatigue, or related physiological factors were reviewed. The findings suggest that with moderate dehydration, there is a decrease in total brain volume accompanied with expansion of ventricular volume. With exercise fatigue, there is increased activation of sensorimotor and cognitive brain areas, increased thalamo-insular activation and decreased interhemispheric connectivity in motor cortex. Under passive hyperthermia, there are regional changes in cerebral perfusion, a reduction in local connectivity in functional brain networks and an impairment to executive function. Current literature suggests that the brain structure and function are influenced by exercise, fatigue, and related physiological perturbations. However, there is still a dearth of knowledge and it is hoped that through understanding of MRI advantages and limitations, future studies will shed light on the central origin of exertional fatigue in the heat.
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Affiliation(s)
- X R Tan
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore, Singapore
| | - I C C Low
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - M C Stephenson
- Clinical Imaging Research Centre, Agency for Science, Technology and Research - National University of Singapore (A*STAR-NUS), Singapore, Singapore.,Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - T W Soong
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore, Singapore
| | - J K W Lee
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Defence Medical & Environmental Research Institute, DSO National Laboratories, Singapore, Singapore
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22
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Kamendi H, Barthlow H, Lengel D, Beaudoin ME, Snow D, Mettetal JT, Bialecki RA. Quantitative pharmacokinetic-pharmacodynamic modelling of baclofen-mediated cardiovascular effects using BP and heart rate in rats. Br J Pharmacol 2016; 173:2845-58. [PMID: 27448216 DOI: 10.1111/bph.13561] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 06/29/2016] [Accepted: 07/02/2016] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND AND PURPOSE While the molecular pathways of baclofen toxicity are understood, the relationships between baclofen-mediated perturbation of individual target organs and systems involved in cardiovascular regulation are not clear. Our aim was to use an integrative approach to measure multiple cardiovascular-relevant parameters [CV: mean arterial pressure (MAP), systolic BP, diastolic BP, pulse pressure, heart rate (HR); CNS: EEG; renal: chemistries and biomarkers of injury] in tandem with the pharmacokinetic properties of baclofen to better elucidate the site(s) of baclofen activity. EXPERIMENTAL APPROACH Han-Wistar rats were administered vehicle or ascending doses of baclofen (3, 10 and 30 mg·kg(-1) , p.o.) at 4 h intervals and baclofen-mediated changes in parameters recorded. A pharmacokinetic-pharmacodynamic model was then built by implementing an existing mathematical model of BP in rats. KEY RESULTS Final model fits resulted in reasonable parameter estimates and showed that the drug acts on multiple homeostatic processes. In addition, the models testing a single effect on HR, total peripheral resistance or stroke volume alone did not describe the data. A final population model was constructed describing the magnitude and direction of the changes in MAP and HR. CONCLUSIONS AND IMPLICATIONS The systems pharmacology model developed fits baclofen-mediated changes in MAP and HR well. The findings correlate with known mechanisms of baclofen pharmacology and suggest that similar models using limited parameter sets may be useful to predict the cardiovascular effects of other pharmacologically active substances.
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Affiliation(s)
- Harriet Kamendi
- Drug Safety and Metabolism, AstraZeneca-US, Waltham, MA, USA
| | | | - David Lengel
- Drug Safety and Metabolism, AstraZeneca-US, Waltham, MA, USA
| | | | - Debra Snow
- Drug Safety and Metabolism, AstraZeneca-US, Waltham, MA, USA
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23
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Bain AR, Nybo L, Ainslie PN. Cerebral Vascular Control and Metabolism in Heat Stress. Compr Physiol 2016; 5:1345-80. [PMID: 26140721 DOI: 10.1002/cphy.c140066] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This review provides an in-depth update on the impact of heat stress on cerebrovascular functioning. The regulation of cerebral temperature, blood flow, and metabolism are discussed. We further provide an overview of vascular permeability, the neurocognitive changes, and the key clinical implications and pathologies known to confound cerebral functioning during hyperthermia. A reduction in cerebral blood flow (CBF), derived primarily from a respiratory-induced alkalosis, underscores the cerebrovascular changes to hyperthermia. Arterial pressures may also become compromised because of reduced peripheral resistance secondary to skin vasodilatation. Therefore, when hyperthermia is combined with conditions that increase cardiovascular strain, for example, orthostasis or dehydration, the inability to preserve cerebral perfusion pressure further reduces CBF. A reduced cerebral perfusion pressure is in turn the primary mechanism for impaired tolerance to orthostatic challenges. Any reduction in CBF attenuates the brain's convective heat loss, while the hyperthermic-induced increase in metabolic rate increases the cerebral heat gain. This paradoxical uncoupling of CBF to metabolism increases brain temperature, and potentiates a condition whereby cerebral oxygenation may be compromised. With levels of experimentally viable passive hyperthermia (up to 39.5-40.0 °C core temperature), the associated reduction in CBF (∼ 30%) and increase in cerebral metabolic demand (∼ 10%) is likely compensated by increases in cerebral oxygen extraction. However, severe increases in whole-body and brain temperature may increase blood-brain barrier permeability, potentially leading to cerebral vasogenic edema. The cerebrovascular challenges associated with hyperthermia are of paramount importance for populations with compromised thermoregulatory control--for example, spinal cord injury, elderly, and those with preexisting cardiovascular diseases.
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Affiliation(s)
- Anthony R Bain
- Centre for Heart Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Okanagan Campus, Kelowna, Canada
| | - Lars Nybo
- Department of Nutrition, Exercise and Sport Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Philip N Ainslie
- Centre for Heart Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Okanagan Campus, Kelowna, Canada
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24
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Keiser S, Flück D, Stravs A, Hüppin F, Lundby C. Restoring heat stress-associated reduction in middle cerebral artery velocity does not reduce fatigue in the heat. Scand J Med Sci Sports 2016; 25 Suppl 1:145-53. [PMID: 25943665 DOI: 10.1111/sms.12345] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/21/2014] [Indexed: 11/27/2022]
Abstract
Heat-induced hyperventilation may reduce PaCO2 and thereby cerebral perfusion and oxygenation and in turn exercise performance. To test this hypothesis, eight volunteers completed three incremental exercise tests to exhaustion: (a) 18 °C ambient temperature (CON); (b) 38 °C (HEAT); and (c) 38 °C with addition of CO2 to inspiration to prevent the hyperventilation-induced reduction in PaCO2 (HEAT + CO2 ). In HEAT and HEAT + CO2 , rectal temperature was elevated prior to the exercise tests by means of hot water submersion and was higher (P < 0.05) than in CON. Compared with CON, ventilation was elevated (P < 0.01), and hence, PaCO2 reduced in HEAT. This caused a reduction (P < 0.05) in mean cerebral artery velocity (MCAvmean ) from 68.6 ± 15.5 to 53.9 ± 10.0 cm/s, which was completely restored in HEAT + CO2 (68.8 ± 5.8 cm/s). Cerebral oxygenation followed a similar pattern. V ˙ O 2 m a x was 4.6 ± 0.1 L/min in CON and decreased (P < 0.05) to 4.1 ± 0.2 L/min in HEAT and remained reduced in HEAT + CO2 (4.1 ± 0.2 L/min). Despite normalization of MCAvmean and cerebral oxygenation in HEAT + CO2 , this did not improve exercise performance, and thus, the reduced MCAvmean in HEAT does not seem to limit exercise performance.
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Affiliation(s)
- S Keiser
- Zurich Center for Integrative Human Physiology (ZIHP), Zurich, Switzerland; Institute of Physiology, University of Zurich, Zurich, Switzerland
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25
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Schlader ZJ, Wilson TE, Crandall CG. Mechanisms of orthostatic intolerance during heat stress. Auton Neurosci 2015; 196:37-46. [PMID: 26723547 DOI: 10.1016/j.autneu.2015.12.005] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 11/30/2015] [Accepted: 12/14/2015] [Indexed: 01/04/2023]
Abstract
Heat stress profoundly and unanimously reduces orthostatic tolerance. This review aims to provide an overview of the numerous and multifactorial mechanisms by which this occurs in humans. Potential causal factors include changes in arterial and venous vascular resistance and blood distribution, and the modulation of cardiac output, all of which contribute to the inability to maintain cerebral perfusion during heat and orthostatic stress. A number of countermeasures have been established to improve orthostatic tolerance during heat stress, which alleviate heat stress induced central hypovolemia (e.g., volume expansion) and/or increase peripheral vascular resistance (e.g., skin cooling). Unfortunately, these countermeasures can often be cumbersome to use with populations prone to syncopal episodes. Identifying the mechanisms of inter-individual differences in orthostatic intolerance during heat stress has proven elusive, but could provide greater insights into the development of novel and personalized countermeasures for maintaining or improving orthostatic tolerance during heat stress. This development will be especially impactful in occuational settings and clinical situations that present with orthostatic intolerance and/or central hypovolemia. Such investigations should be considered of vital importance given the impending increased incidence of heat events, and associated cardiovascular challenges that are predicted to occur with the ensuing changes in climate.
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Affiliation(s)
- Zachary J Schlader
- Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY, United States.
| | - Thad E Wilson
- Marian University College of Osteopathic Medicine, Indianapolis, IN, United States
| | - Craig G Crandall
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX, United States
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26
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Nakata H, Oshiro M, Namba M, Shibasaki M. Effects of passive heat stress on human somatosensory processing. Am J Physiol Regul Integr Comp Physiol 2015; 309:R1387-96. [DOI: 10.1152/ajpregu.00280.2015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 10/14/2015] [Indexed: 11/22/2022]
Abstract
Herein, we investigated the effects of passive heat stress on human somatosensory processing recorded by somatosensory-evoked potentials (SEPs). Fifteen healthy subjects received a median nerve stimulation at the left wrist under two thermal conditions: Heat Stress and normothermic Time Control. The latencies and amplitudes of P14, N20, P25, N35, P45, and N60 at C4′ and P14, N18, P22, and N30 at Fz were evaluated. Under the Heat Stress condition, SEPs were recorded at normothermic baseline (1st), early in heat stress (2nd), when esophageal temperature had increased by ∼1.0°C (3rd) and ∼2.0°C (4th), and after heat stress (5th). In the Time Control condition, SEPs were measured at the same time intervals as those in the Heat Stress condition. The peak latencies and amplitudes of SEPs did not change early in heat stress. However, the latencies of P14, N20, and N60 at C4′ and P14, N18, and P22 at Fz were significantly shorter in the 4th session than in the 1st session. Furthermore, the peak amplitudes of P25 and N60 at C4′, and P22 and N30 at Fz decreased with increases in body temperature. On the other hand, under the Time Control condition, no significant differences were observed in the amplitudes or latencies of any component of SEPs. These results suggested that the conduction velocity of the ascending somatosensory input was accelerated by increases in body temperature, and hyperthermia impaired the neural activity of cortical somatosensory processing.
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Affiliation(s)
- Hiroki Nakata
- Department of Health Sciences, Faculty of Human Life and Environment, Nara Women's University, Nara, Japan; and
| | - Misaki Oshiro
- Graduate School of Humanities and Sciences, Nara Women's University, Nara, Japan
| | - Mari Namba
- Graduate School of Humanities and Sciences, Nara Women's University, Nara, Japan
| | - Manabu Shibasaki
- Department of Health Sciences, Faculty of Human Life and Environment, Nara Women's University, Nara, Japan; and
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27
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Goodall S, Charlton K, Hignett C, Prichard J, Barwood M, Howatson G, Thomas K. Augmented supraspinal fatigue following constant-load cycling in the heat. Scand J Med Sci Sports 2015; 25 Suppl 1:164-72. [DOI: 10.1111/sms.12370] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/15/2014] [Indexed: 12/30/2022]
Affiliation(s)
- S. Goodall
- Faculty of Health and Life Sciences; Department of Sport, Exercise & Rehabilitation; Northumbria University; Newcastle UK
| | - K. Charlton
- Faculty of Health and Life Sciences; Department of Sport, Exercise & Rehabilitation; Northumbria University; Newcastle UK
| | - C. Hignett
- Faculty of Health and Life Sciences; Department of Sport, Exercise & Rehabilitation; Northumbria University; Newcastle UK
| | - J. Prichard
- Institue of Health & Society; Newcastle University; Newcastle UK
| | - M. Barwood
- Faculty of Health and Life Sciences; Department of Sport, Exercise & Rehabilitation; Northumbria University; Newcastle UK
| | - G. Howatson
- Faculty of Health and Life Sciences; Department of Sport, Exercise & Rehabilitation; Northumbria University; Newcastle UK
- Water Research Group; School of Environmental Sciences and Development; Northwest University; Potchefstroom South Africa
| | - K. Thomas
- Faculty of Health and Life Sciences; Department of Sport, Exercise & Rehabilitation; Northumbria University; Newcastle UK
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28
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Brassard P, Ainslie PN, Secher NH. Cerebral oxygenation in health and disease. Front Physiol 2014; 5:458. [PMID: 25505422 PMCID: PMC4241837 DOI: 10.3389/fphys.2014.00458] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 11/07/2014] [Indexed: 12/26/2022] Open
Affiliation(s)
- Patrice Brassard
- Department of Kinesiology, Faculty of Medicine, Université Laval, Québec QC, Canada
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia-Okanagan Kelowna, BC, Canada
| | - Niels H Secher
- The Copenhagen Muscle Research Center, Department of Anesthesia, University of Copenhagen Copenhagen, Denmark
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