Our circadian world shapes much of metabolic physiology. In mice ∼40% of the light and ∼80% of the dark phase time is characterized by bouts of increased energy expenditure (EE). These ultradian bouts have a higher body temperature (Tb) and thermal conductance and contain virtually all of the physical activity and awake time. Bout status is a better classifier of mouse physiology than photoperiod, with ultradian bouts superimposed on top of the circadian light/dark cycle. We suggest that the primary driver of ultradian bouts is a brain-initiated transition to a higher defended Tb of the active/awake state. Increased energy expenditure from brown adipose tissue, physical activity, and cardiac work combine to raise Tb from the lower defended Tb of the resting/sleeping state. Thus, unlike humans, much of mouse metabolic physiology is episodic with large ultradian increases in EE and Tb that correlate with the active/awake state and are poorly aligned with circadian cycling.
- MeSH
- bdění fyziologie MeSH
- cirkadiánní rytmus * fyziologie MeSH
- energetický metabolismus * fyziologie MeSH
- fotoperioda * MeSH
- hnědá tuková tkáň metabolismus fyziologie MeSH
- myši MeSH
- spánek fyziologie MeSH
- tělesná teplota * fyziologie MeSH
- ultradiánní rytmus * fyziologie MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Horúčka je častým javom na neurologických jednotkách intenzívnej starostlivosti. Etiologicky najčastejšie ide o infekčnú príčinu, v menšej miere prichádzajú následne do úvahy neinfekčné príčiny, ako trombembolizmus, medikamentózne navodený stav, postoperačné príčiny a v neposlednom rade centrálna neurogénna hypertermia. Ide o diagnózu per exclusionem, ktorá doteraz nemá štandardizované diagnostické kritériá ani liečbu. Rovnako tak nie je úplne objasnený ani patomechanizmus jej vzniku. Článok sa zaoberá prehľadom dostupných údajov o fyziológii termoregulácie, predostiera predpokladaný patofyziologický pôvod danej entity (s dôrazom na problematiku z pohľadu neurológa), zmieňuje sa o prejavoch a dôsledkoch ochorenia, napokon uvádza stručný prehľad možností liečby vrátane off‐label preparátov.
Fever is a common phenomenon within neurological intensive care units. Etiologically, it is most often an infectious cause, to a lesser extent, non-infectious causes come into consideration such as thromboembolism, medically induced condition, postoperative causes and, last but not least, central neurogenic hyperthermia. This is a diagnosis per exclusionem, which does not yet have standardized diagnostic criteria or treatment. Likewise, the pathomechanism of its formation is not fully clarified. The article deals with an overview of available data from the physiology of thermoregulation, lays out the presumed pathophysiological background of the given entity (with an emphasis on the issue from the neurologist's point of view), mentions the symptoms and consequences of the disease, and finally gives a brief overview of treatment options, including off-label preparations.
- MeSH
- hypertermie * diagnóza etiologie farmakoterapie patofyziologie terapie MeSH
- hypothalamus fyziologie MeSH
- lidé MeSH
- mozek patofyziologie MeSH
- nemoci nervového systému klasifikace patofyziologie MeSH
- neurony fyziologie klasifikace MeSH
- rizikové faktory MeSH
- tělesná teplota fyziologie MeSH
- termoregulace fyziologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- kazuistiky MeSH
- přehledy MeSH
- MeSH
- hypertermie * diagnóza etiologie terapie MeSH
- hypotermie * diagnóza etiologie terapie MeSH
- lidé MeSH
- nemoci novorozenců MeSH
- novorozenec MeSH
- tělesná teplota fyziologie MeSH
- Check Tag
- lidé MeSH
- novorozenec MeSH
- Publikační typ
- přehledy MeSH
BACKGROUND: Targeted temperature management (TTM) in comatose survivors of out-of-hospital cardiac arrest has been associated with improved neurological outcomes. However, the optimal temperature target for TTM remains unclear. OBJECTIVES: To compare a TTM protocol targeted at 34-36 °C with a protocol targeted at 32-34 °C with reference to both clinical outcomes and acute complications. METHODS: We analyzed a prospective registry of consecutive out-of-hospital cardiac arrest survivors who underwent TTM. We compared patients on a TTM protocol targeted at 34-36 °C (n = 59) with a historical cohort of patients treated at 32-34 °C (n = 116) according to the following parameters: six-month survival, cerebral performance category (CPC) scores, and acute complications. RESULTS: Survival and favorable neurological outcomes (CPC ≤ 2) at six months were 56% and 49%, respectively, in the higher target temperature group vs. 66% and 61%, respectively, in the lower target temperature group (p = 0.18 and 0.13). Acute clinical complications occurred in 1.5% vs. 12% of patients treated at the higher vs. the lower temperature range (p = 0.02). CONCLUSIONS: Patients treated with TTM at 34-36 °C had similar mid-term survival and neurological outcomes as patients treated with TTM at 32-34 °C. However, patients treated within the higher temperature range had fewer acute complications.
- MeSH
- časové faktory MeSH
- kardiopulmonální resuscitace metody MeSH
- lidé středního věku MeSH
- lidé MeSH
- následné studie MeSH
- prospektivní studie MeSH
- registrace * MeSH
- tělesná teplota fyziologie MeSH
- terapeutická hypotermie metody MeSH
- výsledek terapie MeSH
- zástava srdce mimo nemocnici patofyziologie terapie MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
The study investigated whether changes in body surface temperature in a sprint interval testing protocol (SITP) correlated with aerobic capacity in cyclists. The study involved 21 well-trained cyclists. Maximal aerobic power and maximal oxygen uptake relative to lean body mass (LBM-P(max) and LBM-VO(2max), respectively) were determined by incremental exercise testing on a cycle ergometer. SITP was administered 48 hours later and involved four 30-s maximal sprints interspersed with 90-s active recovery. Body surface temperature was recorded at the temple and arm and the delta difference between baseline temperature and temperature measured immediately after the first sprint (DeltaTt(1) and DeltaTa(1), respectively) and 80 seconds after the fourth sprint (DeltaTt(4) and DeltaTa(4)), respectively) was calculated. Significant correlations were found between DeltaTt4 and LBM-Pmax and LBM-VO(2max) (r=0.63 and r=0.75, respectively) with no significant change in DeltaTa(1) or DeltaTa(4). Body surface temperature, measured at the temple region, can be used to indirectly assess aerobic capacity during maximal sprint exercise.
- MeSH
- cvičení fyziologie MeSH
- cyklistika fyziologie MeSH
- fyzická vytrvalost fyziologie MeSH
- fyziologie kůže * MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- spotřeba kyslíku fyziologie MeSH
- tělesná teplota fyziologie MeSH
- tolerance zátěže fyziologie MeSH
- zátěžový test metody MeSH
- Check Tag
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
In this study we set out to understand is sleep fragmentation affects the cardiovascular regulation and circadian variability of core body temperature more or less than sleep deprivation. 50 healthy men (age 29.0+/-3.1 years; BMI 24.3+/-2.1 kg/m(2)) participated in a 3-day study that included one adaptative night and one experimental night involving randomization to: sleep deprivation (SD) and sleep fragmentation (SF). The evaluation included hemodynamic parameters, measures of the spectral analysis of heart rate and blood pressure variability, and the sensitivity of arterial baroreflex function. Core body temperature (CBT) was measured with a telemetric system. SF affects heart rate (61.9+/-5.6 vs. 56.2+/-7.6, p<0.01) and stroke index (52.7+/-11.1 vs. 59.8+/-12.2, p<0.05) with significant changes in the activity of the ANS (LF-sBP: 6.0+/-5.3 vs. 3.4+/-3.7, p<0.05; HF-sBP: 1.8+/-1.8 vs. 1.0+/-0.7, p<0.05; LF-dBP: 5.9+/-4.7 vs. 3.5+/-3.2, p<0.05) more than SD. Post hoc analysis revealed that after SD mean value of CBT from 21:30 to 06:30 was significantly higher compared to normal night's sleep and SF. In healthy men SF affects the hemodynamic and autonomic changes more than SD. Sympathetic overactivity is the proposed underlying mechanism.
- MeSH
- dospělí MeSH
- krevní tlak fyziologie MeSH
- lidé MeSH
- mladý dospělý MeSH
- spánková deprivace diagnóza patofyziologie MeSH
- srdeční frekvence fyziologie MeSH
- stadia spánku fyziologie MeSH
- tělesná teplota fyziologie MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- randomizované kontrolované studie MeSH
- srovnávací studie MeSH
Humans' core body temperature (CBT) is strictly controlled within a narrow range. Various studies dealt with the impact of physical activity, clothing, and environmental factors on CBT regulation under terrestrial conditions. However, the effects of weightlessness on human thermoregulation are not well understood. Specifically, studies, investigating the effects of long-duration spaceflight on CBT at rest and during exercise are clearly lacking. We here show that during exercise CBT rises higher and faster in space than on Earth. Moreover, we observed for the first time a sustained increased astronauts' CBT also under resting conditions. This increase of about 1 °C developed gradually over 2.5 months and was associated with augmented concentrations of interleukin-1 receptor antagonist, a key anti-inflammatory protein. Since even minor increases in CBT can impair physical and cognitive performance, both findings have a considerable impact on astronauts' health and well-being during future long-term spaceflights. Moreover, our findings also pinpoint crucial physiological challenges for spacefaring civilizations, and raise questions about the assumption of a thermoregulatory set point in humans, and our evolutionary ability to adapt to climate changes on Earth.
- MeSH
- časové faktory MeSH
- kosmický let MeSH
- kosmonauti * MeSH
- lidé MeSH
- stav beztíže MeSH
- tělesná teplota fyziologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Perioperační hypotermie je závažnou komplikací anestezie a je spojena s mnoha nepříznivými důsledky, mezi něž patří oběhová nestabilita, útlum dýchání a prodloužení účinků anestetik. Největší opatrnosti si zaslouží novorozenci a malé děti, které mají větší sklon ke snížení tělesné teploty během operačního výkonu pro relativně velký tělesný povrch a tenkou vrstvu podkožního tuku. Hlavními mechanismy tepelných ztrát na operačním sále jsou odvedení a vyzařování tepla, proudění vzduchu a odpařování. Optimální tepelné homeostázy v průběhu anestezie dítěte lze dosáhnout kombinací řady postupů, např. použitím teplovzdušných matrací, voděodolného rouškování, ohřívání infuzních roztoků nebo zamezení proudění vzduchu kolem pacienta. Perioperační teplotu těla lze měřit kožním, jícnovým, rektálním či tympanálním teploměrem nebo přístrojem SpontOn pomocí vytvořeného izotermického kanálu do tělesného tepelného jádra. Spolehlivé měření tělesné teploty slouží též k prevenci arteficiálně navozené hypertermie.
Perioperative hypothermia is a serious complication of anaesthesia and is associated with many adverse consequences, including circulatory instability, respiratory depression and prolonged effects of the anaesthetics. The greatest caution should be applied to newborns and young children who are more prone to perioperative decrease in body temperature because of their relatively large body surface area and a thin layer of subcutaneous fat. The main mechanisms of heat loss in the operating theatre are conduction and radiation, convection and evaporation. Optimum thermal homeostasis during anaesthesia in children can be achieved through combining various procedures, e.g. using warming-up air mattresses, waterproof drapes, warming of infusion solutions, or preventing airflow around the patient. Perioperative body temperature can be measured using skin, oesophageal, rectal and tympanic thermometers, or the SpontOn device, which creates and uses an isothermal channel into the body core. Reliable body temperature measurement also helps to prevent iatrogenic hyperthermia.
- Klíčová slova
- dětská anestezie, měření tělesné teploty, tepelná homeostáza,
- MeSH
- celková anestezie * škodlivé účinky MeSH
- hypotermie * diagnóza etiologie komplikace prevence a kontrola MeSH
- kojenec MeSH
- lidé MeSH
- novorozenec MeSH
- peroperační komplikace * etiologie MeSH
- peroperační monitorování metody přístrojové vybavení MeSH
- peroperační péče MeSH
- tělesná teplota fyziologie MeSH
- teploměry MeSH
- termoregulace fyziologie MeSH
- Check Tag
- kojenec MeSH
- lidé MeSH
- novorozenec MeSH
- Publikační typ
- práce podpořená grantem MeSH
- přehledy MeSH
To improve the knowledge in chronophysiology we investigated the causal link between the most important physiological variable studied until now; ten Sarda ewes and ten Sarda goats, pluriparus not pregnant and no lactating, were used. Animals were housed under natural environmental conditions in a common stall, alfalfa hay and water were available ad libitum. Each animal was equipped with an Actiwatch-Mini® for recording total activity. Blood samples were collected every 4 h over a 48 h period for the assessment of melatonin concentration. Rectal temperature was recorded with a digital thermometer immediately before the blood sampling at each data point. Single cosinor method showed a daily rhythm of studied variables. Higher MESOR and amplitude values of melatonin and rectal temperature were observed in sheep than in goats. The diurnal acrophase of locomotor activity was statistically different from the nocturnal acrophase of melatonin and rectal temperature, with no differences between the two species. Robustness was statistically lower in total locomotor activity in comparison with the others two variables, with a differences due to species in melatonin daily rhythm. In conclusion, in small ruminants, melatonin and rectal temperature daily rhythms are strictly correlated, and are not associated with the locomotor activity rhythm.
- MeSH
- hypertermie * etiologie MeSH
- infekční nemoci MeSH
- lidé MeSH
- maligní hypertermie MeSH
- tělesná teplota fyziologie účinky léků MeSH
- vysoká teplota MeSH
- změny tělesné teploty MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
