Thermoregulation Research Articles

Thermosensitive TRP ion channels in regulation of thermoregulatory and immune functions in homoeothermic organism

Thermosensitive TRP ion channels in regulation of thermoregulatory and immune functions in homoeothermic organism

Heat-seeking sharks: support for behavioural thermoregulation in reef sharks

Most fish are ectotherms and for this reason, water temperature is thought to be one of the main physical determinants of behaviour. We tested the hypothesis that be havioural thermo regulation occurs in 4 species of reef sharks (n = 58), where water temperature influences patterns of long-term (>1 yr) movement, by analysing acoustic monitoring and environmental datasets. We also used biotelemetry to measure the body temperature of 5 adult female blacktip reef sharks Carcharhinus melanopterus in response to changes in water temperature, to test whether they participate in inshore aggregations potentially to increase metabolic rates. We found that water temperature had the greatest influence on shark presence at each of our study sites (deviance explained = 3.7−54.6%), when compared to other variables. On average, body temperatures of female blacktip reef sharks were consistently warmer than average (±SE) water temperature by 1.3 ± 0.57°C, providing support for behavioural thermoregulation. The maximum body temperature of blacktip reef sharks while at the aggregation site corresponded to peak daily water temperatures. The average hourly body temperature varied little among individuals. Our models showed that the relationship between water temperature and the presence of female blacktip reef sharks was strongest at the aggregation site relative to other sites. These results suggest that reef shark movements are influenced by water temperature and provide additional support for the behavioural thermoregulation hypothesis. Such data are necessary for predicting how sharks might be affected by climate change and other human modifications to water temperature patterns.

Getting a kick out of thermoregulation

Getting a kick out of thermoregulation

Thermoregulation and neuroanesthesia

Thermoregulation and neuroanesthesia

Metabolism and thermoregulation between Mrs Hume's Pheasant (Syrmaticus humiae) and Elliot's Pheasant (S. ellioti).

To understand metabolic adaptations, the basal metabolic rate (BMR) of Mrs Hume's Pheasant (Syrmaticus humiae) and Elliot's Pheasant (Syrmaticus ellioti) were investigated. Metabolic rate (MR), body temperature (T(b) ) and thermal conductance (C) were determined in both species at a temperatrue range of 5-35 Degrees Celsius, respectively. Oxygen consumption was measured with a closed circuit respirometer. The thermal neutral zones (TNZ) were 24.5-31.6 Degrees Celsius, and 23.0-29.2 Degrees Celsius, respectively. With a temperature range of 5-35 Degrees Celsius, Mrs Hume's Pheasant and Elliot's Pheasant could maintained stable T(b) at a mean of (40.47 ± 0.64) and (40.36 ± 0.10) Degrees Celsius, respectively. Mean BMRs within TNZs were (1.36 ± 0.84) mLO₂/(g.h) for Mrs Hume's Pheasant and (2.03 ± 0.12) mLO₂/(g.h) for Elliot's Pheasant, which were 77% and 86% of the expected value based on their body mass, respectively. Thermal conductance of Mrs Hume's Pheasant and Elliot's Pheasant were (0.12 ± 0.01) and (0.17 ± 0.01) mLO₂/(g.h.Degrees Celsius), below the lower critical temperature, respectively, which were 119% and 124% of the expected value based on their body mass, respectively. The ecophysiological characteristics of these species were low metabolic rate, high body temperature, and high thermal conductance, which allow both species to better adapt to the warmer climate environment in south China.

Effect of clipping feathers, dietary ascorbic acid supplementation and season on performance of laying chickens

Feathers may be problematic to chickens in thermoregulation during heat stress. This study was conducted to investigate the effect of clipping feathers, dietary ascorbic acid supplementation and season on performance of laying chickens. 180 ‘Isa Brown’ (IB) layers of about 30 weeks old were subjected to a 2×2×2 factorial combination of feather conditions (intact and clipping), dietary ascorbic acid supplementation (0 and 300 ppm) and season (early dry, ED and late dry, LD) during a trial using a factorial design. The birds were randomly allotted to 8 treatments consisting of treatment one (basal diet and intact feathers); treatment two (basal diet and clipped feathers); treatment three (basal diet supplemented with 300 ppm ascorbic acid and intact feathers) and treatment four (basal diet supplemented with 300 ppm ascorbic acid and clipped feathers) in both ED and LD seasons. Results showed that clipping feathers significantly improved (P 0.05) on HDP, WI, F/Doz., EW, and ESW. However, the effect of the interactions of the three factors were not significant (P>0.05) on FC, EM, EST and %ESW. Finally, clipping of feathers alone; secondly, dietary ascorbic acid supplementation at 300 ppm alone; and thirdly, a combination of the two, can be efficient in condition of heat stress. Key words: Feathers, ascorbic acid, season.

Effect of positive end expiratory pressure on thermo-regulatory function during general anesthesia in patients addicted to smoking

Objective To investigate the effect of positive end expiratory pressure (PEEP) on thermo-regulatory function during general anesthesia in patients addicted to smoking. Methods Twenty adult male ASA Ⅰ or Ⅱ patients who had been smoking more than or equal to 10 cigarettes per day for more than or equal to 6 years were studied. The patients underwent intra-abdominal surgery under general anesthesia and were randomly divided into 2 groups ( n = 10 each): control group (group C) and PEEP group (group P). Anesthesia was induced with propofol, fentanyl and vecuronium and maintained with inhalation of 1%-2% isoflurane and continuous iv infusion of remifentanil and vecuronium. The patients were mechanically ventilated after tracheal intubation. In group P PEEP of 10 cm H2O was added. Temperature probe was inserted into the lower segment of esophagus and placed on the anterior chest wall, medial surface of thigh anterior surface of forearm and palmar surface of the tip of index finger. Mean skin temperature (TMSK) was calculated according to Roberts. MAP, HR, TES, TMSK and the difference between TES and TMSK (TES-MSK) were recorded before induction of anesthesia (T0 ,baseline) and every 30 min after tracheal intubation. Esophageal temperature was taken as threshold of thermo-regulatory peripheral vasoconstriction when the difference between forearm and finger tip temperature = 0 ℃. The gain in the threshold was calculated according to Sessler. Results TES and TES-MSK significantly decreased,while TMsK increased after tracheal intubation in both groups ( P ＜ 0.05). There was no signifieant difference in TES, TMSK, TES-MSK, MAP, HR, the threshold of vasoconstriction and gain between the 2 gronps ( P ＞ 0.05). Conclusion PEEP cannot improve thermo-regulatory function during general anesthesia in smoking-addicted patients. Key words: Respiration, artificial; Body temperature regulation; Smoking; Anesthesia,general

Analysis of the Lotus Thermoregulation System from the Perspective of Control Engineering

発熱期のハスの体温調節機構を解析するために, ハスを鉢栽培し, 屋外で開花開始から種子結実終了までのハスの花托体温と気温の関係を調べる屋外実験を実施した. 同時に, 発熱期および無発熱期のハスを恒温槽に入れ槽内温度を階段関数的に変化させそのときの花托体温のステップ応答を測定する屋内実験を実施した. (i)これら屋外と屋内の2実験において, 周囲気温を入力, そのときの花托体温を出力とする入出力関係を伝達関数で表現した. (ii)他方, 屋外実験(太陽光による一種の周波数応答実験)の解析を行い, 自然環境下の発熱期のハスが気温の変動を組み込んで自己の花托体温を決定するというハスの体温調節モデルを導出した. (iii)最後に, iとiiの結果に制御理論を適用して, ハスの体温制御機構を総合的に検討した. 得られた主な結果は以下の通りである.(1)発熱期のハスは, ある種の体内温度計を内臓し, これと時々刻々変動する気温の影響の和を目標値とする, 可変目標値モデル提案した.(2)発熱の活性化の程度は活性化係数で表すことができ, 発熱はステージ2の場合が, 最も活性化係数が大きくて発熱活動が最も盛んであることを確認した.(3)ハスの花托体温と気温依存温度の差は発熱相当温度であり, 花托は発熱相当温度分の熱産生を行って体温を気温より高温に保っていると考えられる.(4)ハスの体温制御系は, 発熱期の花托体温をフィードバックし可変目標値との偏差を制御器に導くという制御機構で表すことができる.(5)気温からハス花托に至る伝達関数は一次遅れ系で, 発熱期の制御器は積分動作で表現することができる.

Yawning and thermoregulation

Yawning and thermoregulation

The anatomical variability and the functional role of the middle meningeal artery

The middle meningeal artery is one of the main component of the dural vascular networks, covering the parietal, temporal and part of the frontal meningeal regions. Usually it arises from the maxillary branch of the external carotid artery and enters the middle cranial fossa trough the foramen spinosum. Here it passes into the meningeal layers and divides in two principal branches from which arise minor vessels which form a complex vascular network between the cortical brain surface and the endocranial wall. Anatomical studies suggest that the middle meningeal artery shows a high anatomical variability both in terms of origin and branching patterns. Furthermore it’s functional role and the relations with the other encephalic circular network are not thoroughly clear. Tri-dimensional angiotomography reconstructions can provide interesting insights in this sense. In most individuals the middle meningeal artery cannot be segmented because the contrast enters only in the basal portion of the network. As a consequence the upper and middle parts of the meningeal vessel are not visible, while the traces of the channels can be easily recognised on the endocranial wall. These results suggest a scarce, discontinuous or absent blood flow, possibly associated with functions restricted to specific physiological situations or even closure of the vessels by connective/fat tissues. When it can be visualised, the tri-dimensional reconstructions suggest punctual contacts between the middle meningeal vessels and the middle cerebral artery, which run laterally, share a short tract with the middle meningeal artery and than came back into the encephalic tissues. On the other hand it is impossible to visualize eventual connections between the meningeal network and the diploic and extra-cranial vessels. The functional role of this complex vascular network could be interpreted both in terms of metabolic and biomechanical adaptations. The former is associated with oxygenation and thermoregulation of the meningeal layers, the second with a protection role of the vessels which act as a hydrodynamic skeleton. Nevertheless, because of the lack of large anatomical comparative database and taking in account the limits of the angiotomagriphic reconstructions, these results should be considered as preliminary. Information on the anatomical variations of these vessels is needed to support useful hypotheses in vascular biomedicine and neurosurgery, as well as in human evolution.

Yawning and thermoregulation in budgerigars: lack of support from results

Yawning and thermoregulation in budgerigars: lack of support from results

Toward a Fuzzy Logic Control of the Infant Incubator

Premature birth is a world wide problem. Thermo regulation is a major problem in premature infants. Premature infants are often kept in infant incubators providing convective heating. Currently either the incubator air temperature is sensed and used to control the heat flow, or infant's skin temperature is sensed and used in the close loop control. Skin control often leads to large fluctuations in the incubator air temperature. Air control also leads to skin temperature fluctuations. The question remains if both the infant's skin temperature and the incubator air temperature can be simultaneously used in the control. The purpose of the present study was to address this question by developing a fuzzy logic control which incorporates both incubator air temperature and infant's skin temperature to control the heating. The control was evaluated using a lumped parameter mathematical model of infant-incubator system (Simon, B. N., N. P. Reddy, and A. Kantak, J. Biomech. Eng. 116:263-266, 1994). Simulation results confirmed previous experimental results that the on-off skin control could lead to fluctuations in the incubator air temperature, and the air control could lead to too slow rise time in the core temperature. The fuzzy logic provides a smooth control with the desired rise time.

P8 Arousal, Stress, Thermoregulation and Conditioning: P8.1 Panting rats: New index of arousal?

P8 Arousal, Stress, Thermoregulation and Conditioning: P8.1 Panting rats: New index of arousal?

Free Communication/Poster - Hydration, Thermoregulation, and Performance

Free Communication/Poster - Hydration, Thermoregulation, and Performance

Prise en charge de l’hyperhidrose axillaire idiopathique

Hyperhidrosis is considered as an handicap which affects around of 2.8% of the population. It is linked to an extreme, permanent and symetric production of sweating because of an hyperactivity of sweat glands independant of thermo regulation process. The treatment by botulinum toxin has completely changed the treatment of axillary hyperhidrosis. It is an easy, quick, efficient treatment which improved quality of life of these patients. This treatment can also be used for palmar and plantar hyperhidrosis but it requires regional anesthetic technics, so it is done to the hospital.

THERMOREGULATION: RECENT CONCEPTS AND REMAINING QUESTIONS

THERMOREGULATION: RECENT CONCEPTS AND REMAINING QUESTIONS

Variação anual de hormônios tireoideanos e características termorreguladoras de vacas leiteiras em ambiente quente

Este trabalho foi conduzido com o objetivo de estudar o comportamento anual de características termorreguladoras de 200 vacas leiteiras. Durante dois anos consecutivos, foram registradas a freqüência respiratória (FR) e a temperatura retal (TR), bem como coletada uma amostra de sangue para dosagens de triiodotironina (T3) e tiroxina (T4). Foram também registradas a temperatura e a umidade do ar e calculados o índice de temperatura de globo e umidade (ITGU) e a carga térmica radiante (CTR), nos mesmos dias de coleta. Houve efeito significativo do ano para a maioria das variáveis estudadas, no entanto, os efeitos do mês de coleta e do rebanho foram significativos para todas. Todos os valores de TR estiveram dentro da amplitude de normalidade, indicando homeotermia. A FR foi alterada em todas as épocas do ano e rebanhos, confirmando a necessidade constante de termólise. No rebanho de maior TR e a FR, houve redução da secreção de T3 e T4. Nas épocas de maiores ITGU e CTR, houve aumento da TR, seguido de maiores FR e menores concentrações plasmáticas de T3 e T4.

Thermoregulation: Hot and cold skinks

Thermoregulation: Hot and cold skinks

DECREASING THE EFFECTS OF THE PHYSICAL FIELDS UPON LIVING BODIES, (BLOOD) USING A.D. BIOPHYTOMODULATORS

Biophytomodulators are equipment formed of liquid crystals, which can be found in the organs of the plants. The combinations between these cryst als assure a large oscillations way transporting en ergy upon the subject. The issue of protecting the living world, against b ad effects produced by the exposure to electromagne tic fields subscribes in European Recommendation 1999/519/CE, which contains precaution principle in the European Union Treat (Art. 130 R Malstrich - 7 feb. 1992). Our experiments belong to the fundamental research, referring to the exposure of animal blood to intense electric fields, following the sediment speed, and also the protection methods by using phyto-byo-dynamic devices (vegetal lasers - Ancu-Dinca). It is known that the blood as a dynamic tissue par ticipate by its plasmatic and cell compounds to form and adjust the main function of t he organism, assuring the unitary character maintained homeostasis. By the major physiological role of blood tissue we take into account: gases and substances transport (different nutrients, O 2, CO 2, ions, acids, bases, cofactors, hormones, vitamins, pigments, minerals, water); immunity prot ection (cells by leukocytes phagocytes activity and humeral) by transporting immunological proteins specific and non-specific - antibodies); homeostasis ensurrement by physic and cell mechanisms); homeostasis maintaining (the constant pH, ionic concentration, osmolarity, temperature, circular nutrient, vascular integrity). In organism, the blood has the following function: nutrient, respiratory, excretory, circulatory and maintaining the hydro-electrolytic and acid-basic equilibrium, of thermo regulation, by protection, humeral coordination and ensurement of organism unity.

Adaptive system for electrically driven thermoregulation of moulds for injection moulding

One of the basic problems in the development and production process of moulds for injection moulding is the control of temperature conditions in the mould. Nowadays temperature is controlled through mould cooling system, which consists of cooling channels, where the cooling fluid transports the needed heat to/from the mould. Such systems control heat exchange process through entire mould, what is in nowadays complex shape and material processing demands insufficient. Owing to this fact, it is mandatory to develop a new system, which will allow fast and precisely located temperature changes in predefined mould locations. In the paper the authors will present results of the research project, which was carried out in three phases and its results patented in PCT/EP2007/003471.1 The main results of the project were total and rapid online thermo regulation of the mould over the cycle time and overall quality of plastic product with emphasis on deformation control. The presented application represents a milestone on the field of mould temperature and product quality control during the injection moulding process.