scholarly journals Autoregulation of the Brain Temperature during Whole Body Hyperthermia

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Haim I. Bicher ◽  
Nodar Mitagvaria ◽  
Marina Devdariani ◽  
Lia Davlianidze ◽  
Marina Nebieridze ◽  
...  

The aim of this study was revealing the temperature changes in rats' brain tissue caused by whole body hyperthermia. The analysis of received results allows to conclude that the brain has a highly secured system of temperature autoregulation against the exogenous temperature changes. The upper limit of this autoregulation (for rats, at least) is in the range of 45°C of environment. An important role in the normal functioning of the brain temperature autoregulation system belongs to Nitric Oxide. The behavioral disorders, observed in animals after whole body hyperthermia (sure within the range of brain temperature autoregulation) are hardly associated with the changes in temperature of the Central Nervous System, but rather have to be mediated by impaired blood circulation and oxygen supply to the brain tissues, caused by the rapid deterioration of the blood rheological properties.

Author(s):  
Audrey Rousseaud ◽  
Stephanie Moriceau ◽  
Mariana Ramos-Brossier ◽  
Franck Oury

AbstractReciprocal relationships between organs are essential to maintain whole body homeostasis. An exciting interplay between two apparently unrelated organs, the bone and the brain, has emerged recently. Indeed, it is now well established that the brain is a powerful regulator of skeletal homeostasis via a complex network of numerous players and pathways. In turn, bone via a bone-derived molecule, osteocalcin, appears as an important factor influencing the central nervous system by regulating brain development and several cognitive functions. In this paper we will discuss this complex and intimate relationship, as well as several pathologic conditions that may reinforce their potential interdependence.


1976 ◽  
Vol 40 (5) ◽  
pp. 653-657 ◽  
Author(s):  
K. A. Smiles ◽  
R. S. Elizondo ◽  
C. C. Barney

A technique is presented for preparing a durable thermode implant in the hypothalamus of the rhesus monkey. In unanesthetized monkeys implanted with thermodes in the anterior hypothalamic area of the brain, a linear relation was found between local sweat rates on the general body surface and clamped hypothalamic temperature. Changes in skin temperature were found to shift the hypothalamic set-point temperature at which sweating began but did not alter the gain of the hypothalamic temperature-sweat rate relationship. This study provides direct support for the concept that central brain temperature and skin temperature interact additively in the control of sweating in higher primates. Due to the very close similarity between these responses and those seen with indirect measurements of brain temperature in men, the rhesus monkey is seen as an excellent experimental analogue for studying human thermoregulation.


1976 ◽  
Vol 40 (4) ◽  
pp. 543-548 ◽  
Author(s):  
R. W. Carithers ◽  
R. C. Seagrave

Extreme whole-body hyperthermia was achieved without lasting side effects in canines by elevating body core temperature to 42 degrees C, using a warm water bath. Cold water irrigation of the nasal alar fold permitted an additional core temperature elevation of 0.5–1.0 degrees C above brain temperature for periods up to 1.5 h. The brain-core temperature differential was maintained by a physiological arteriovenous heat exchanger located at the base of the brain. The maximum tolerable core temperature for the 21 nonirrigated dogs was 42 degrees C for 60–90 min, whereas that for the 28 irrigated dogs was 42.5–43 degrees C for similar time intervals. A mathematical model of the total heat transfer system described the observed dynamic temperature responses. It was the solution of a differential equation which fit the normalized experimental data points and predicted reasonable values for known and unknown experimental parameters.


2021 ◽  
Vol 12 ◽  
Author(s):  
Samuel Fleury ◽  
Imane Boukhatem ◽  
Jessica Le Blanc ◽  
Mélanie Welman ◽  
Marie Lordkipanidzé

Platelets and neurons share many similarities including comparable secretory granule types with homologous calcium-dependent secretory mechanisms as well as internalization, sequestration and secretion of many neurotransmitters. Thus, platelets present a high potential to be used as peripheral biomarkers to reflect neuronal pathologies. The brain-derived neurotrophic factor (BDNF) acts as a neuronal growth factor involved in learning and memory through the binding of two receptors, the tropomyosin receptor kinase B (TrkB) and the 75 kDa pan-neurotrophic receptor (p75NTR). In addition to its expression in the central nervous system, BDNF is found in much greater quantities in blood circulation, where it is largely stored within platelets. Levels 100- to 1,000-fold those of neurons make platelets the most important peripheral reservoir of BDNF. This led us to hypothesize that platelets would express canonical BDNF receptors, i.e., TrkB and p75NTR, and that the receptors on platelets would bear significant resemblance to the ones found in the brain. However, herein we report discrepancies regarding detection of these receptors using antibody-based assays, with antibodies displaying important tissue-specificity. The currently available antibodies raised against TrkB and p75NTR should therefore be used with caution to study platelets as models for neurological disorders. Rigorous characterization of antibodies and bioassays appears critical to understand the interplay between platelet and neuronal biology of BDNF.


Author(s):  
Liang Zhu ◽  
Chenguang Diao

In recent years, mild or moderate hypothermia during which brain temperature is reduced to 30–35°C has been proposed for clinical use as an adjunct for achieving protection from cerebral ischemia and traumatic brain injury. There are two approaches for achieving a reduction in brain temperature. One is via systemic hypothermia where the whole body is cooled. This approach may produce deleterious systemic complications and require intensive monitoring. Another approach is called selective brain cooling (SBC) in which the brain is selectively cooled while the rest of the body is kept at normal temperature. Clinically feasible SBC protocols include head hood or helmet with water or chemical cooling, head immersion in iced water, nasophyaryngeal cooling after tracheal intubation, and intro-carotid flushing. Simply packing ice or wearing cooling helmet is easy to implement. Previous theoretical study [Zhu and Diao, 2001] suggests that it is feasible to achieve mild hypothermia via head surface cooling. However, most physicians believe that it takes a much longer time to reduce the brain temperature using head surface cooling. In this study, a three-dimensional theoretical model is developed to study the transient and steady state temperature distribution in the brain during SBC. The effect of regionally varying local blood perfusion rate in the brain tissue on the temporal and spatial temperature gradient is examined. Other factors including the brain size and the thermal contact resistance between the cooling medium and the head scalp are evaluated in the simulation.


1997 ◽  
Vol 273 (4) ◽  
pp. R1246-R1253 ◽  
Author(s):  
Michael K. Hansen ◽  
James M. Krueger

The mechanism by which peripheral cytokines signal the central nervous system to elicit central manifestations of the acute phase response remains unknown. Recent evidence suggests that cytokines may signal the brain via the vagus nerve. To test this possibility, we examined sleep-wake activity and brain temperature (Tbr) after the intraperitoneal administration of saline or three doses (0.1, 0.5, and 2.5 μg/kg) of interleukin-1β (IL-1β) in subdiaphragmatically vagotomized (Vx) and sham-operated (Sham) rats. The lowest dose of IL-1β (0.1 μg/kg) increased non-rapid eye movement sleep (NREMS) and slightly elevated Tbr in Sham rats; both responses were blocked in Vx animals. The middle dose tested (0.5 μg/kg) increased NREMS and Tbr in Sham animals; however, in Vx rats, the increase in NREMS was attenuated and the increase in Tbr was blocked. The highest dose of IL-1β used (2.5 μg/kg) induced increases in NREMS, decreases in rapid eye movement sleep, and a hypothermic response followed by a biphasic fever; these responses were similar in both Sham and Vx rats. These data provide strong evidence that the subdiaphragmatic vagus plays an important role in communicating both sleep and fever signals to the brain. However, there is clearly an alternative pathway by which IL-1 can signal the brain; whether it occurs through activation of other vagal afferents or through direct or indirect actions on the brain remains unknown.


2019 ◽  
Vol 3 (1) ◽  
pp. 1 ◽  
Author(s):  
Mohammad Fazel Bakhsheshi ◽  
Marjorie Ho ◽  
Lynn Keenliside ◽  
Ting-Yim Lee

Introduction: Selective brain cooling can minimize systemic complications associated with whole body cooling but maximize neuroprotection. Recently, we developed a non-invasive, portable and inexpensive system for selectively cooling the brain rapidly and demonstrated its safety and efficacy in porcine models. However, the widespread application of this technique in the clinical setting requires a reliable, non-invasive and accurate method for measuring local brain temperature so that cooling and rewarming rates can be controlled during targeted temperature management. In this study, we evaluate the ability of a zero-heat-flux SpotOn sensor, mounted on three different locations, to measure brain temperature during selective brain cooling in a pig model. Computed Tomography (CT) was used to determine the position of the SpotOn patches relative to the brain at different placement locations.Methods and Results: Experiments were conducted on two juvenile pigs. Body temperature was measured using a rectal temperature probe while brain temperature with an intraparenchymal thermocouple probe. A SpotOn patch was taped to the pig’s head at three different locations: 1-2 cm posterior (Location #1, n=1), central forehead (Location #2, n=1); and 1-2 cm anterior and lateral to the bregma i.e., above the eye on the forehead (Location #3, n=1). This cooling system was able to rapidly cool the brain temperature to 33.7 ± 0.2°C within 15 minutes, and maintain the brain temperature within 33-34°C for 4-6 hours before slowly rewarming to 34.8 ± 1.1°C from 33.7 ± 0.2°C, while maintaining the core body temperature (as per rectal temperature probe) above 36°C. We measured a mean bias of -1.1°C, -0.2°C and 0.7°C during rapid cooling in induction phase, maintenance and rewarming phase, respectively. Amongst the three locations, location #2 had the highest correlation (R2 = 0.8) between the SpotOn sensor and the thermocouple probe.Conclusions: This SBC method is able to tightly control the rewarming rate within 0.52 ± 0.20°C/h. The SpotOn sensor placed on the center of the forehead provides a good measurement of brain temperature in comparison to the invasive needle probe.


Biomedicines ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 13 ◽  
Author(s):  
Shahryar Shakeri ◽  
Milad Ashrafizadeh ◽  
Ali Zarrabi ◽  
Rasoul Roghanian ◽  
Elham Ghasemipour Afshar ◽  
...  

The blood–brain barrier (BBB) acts as a barrier to prevent the central nervous system (CNS) from damage by substances that originate from the blood circulation. The BBB limits drug penetration into the brain and is one of the major clinical obstacles to the treatment of CNS diseases. Nanotechnology-based delivery systems have been tested for overcoming this barrier and releasing related drugs into the brain matrix. In this review, nanoparticles (NPs) from simple to developed delivery systems are discussed for the delivery of a drug to the brain. This review particularly focuses on polymeric nanomaterials that have been used for CNS treatment. Polymeric NPs such as polylactide (PLA), poly (D, L-lactide-co-glycolide) (PLGA), poly (ε-caprolactone) (PCL), poly (alkyl cyanoacrylate) (PACA), human serum albumin (HSA), gelatin, and chitosan are discussed in detail.


2019 ◽  
Vol 7 ◽  
pp. 2050313X1982853
Author(s):  
Ronie Romelean Jayapalan ◽  
Nor Faizal Ahmad Bahuri ◽  
Kein Seong Mun ◽  
Vairavan Narayanan

Perivascular epithelioid cell tumour is a rare mesenchymal tumour with distinct immunohistochemical profile. While it is known to occur in various anatomical sites, the central nervous system had always been a protected site for primary or secondary perivascular epithelioid cell tumours. We describe a 61-year-old lady who presented with symptoms of raised intracranial pressure, 3 months after the resection of duodenal and thoracic tumours which were histologically consistent with perivascular epithelioid cell tumour. She was investigated and then subsequently subjected to resection of two metastatic intracranial lesions. The radiological, intraoperative as well as histopathological findings of the metastatic lesions are discussed. Metastatic perivascular epithelioid cell tumour of the brain is extremely rare. However, patients who are stratified as high risk for recurrence or metastases should undergo an early magnetic resonance imaging/computed tomography of the brain in addition to a whole-body positron emission tomography scan, to allow for early detection and management of these tumours.


2017 ◽  
Vol 1 (3) ◽  
Author(s):  
Leticia Coelho-Silva ◽  
Gary J. Stephens ◽  
Helena Cimarosti

Small ubiquitin-like modifier (SUMO) conjugation (or SUMOylation) is a post-translational protein modification implicated in alterations to protein expression, localization and function. Despite a number of nuclear roles for SUMO being well characterized, this process has only started to be explored in relation to membrane proteins, such as ion channels. Calcium ion (Ca2+) signalling is crucial for the normal functioning of cells and is also involved in the pathophysiological mechanisms underlying relevant neurological and cardiovascular diseases. Intracellular Ca2+ levels are tightly regulated; at rest, most Ca2+ is retained in organelles, such as the sarcoplasmic reticulum, or in the extracellular space, whereas depolarization triggers a series of events leading to Ca2+ entry, followed by extrusion and reuptake. The mechanisms that maintain Ca2+ homoeostasis are candidates for modulation at the post-translational level. Here, we review the effects of protein SUMOylation, including Ca2+ channels, their proteome and other proteins associated with Ca2+ signalling, on vital cellular functions, such as neurotransmission within the central nervous system (CNS) and in additional systems, most prominently here, in the cardiac system.


Sign in / Sign up

Export Citation Format

Share Document