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63 records – page 1 of 7.

Anterior chamber depth and primary angle-closure glaucoma: an evolutionary perspective.

https://arctichealth.org/en/permalink/ahliterature87425
Source
Clin Experiment Ophthalmol. 2008 Jan-Feb;36(1):70-7
Publication Type
Article
Author
Casson Robert J
Author Affiliation
South Australian Institute of Ophthalmology, Adelaide University, South Australia, Australia. robert.casson@adelaide.edu.au
Source
Clin Experiment Ophthalmol. 2008 Jan-Feb;36(1):70-7
Language
English
Publication Type
Article
Keywords
Adaptation, Physiological
Africa
Anterior Chamber - anatomy & histology
Arctic Regions
Body Temperature Regulation - physiology
Emigration and Immigration
Evolution
Glaucoma, Angle-Closure - ethnology - etiology
Greenland
Humans
Inuits
Abstract
Anterior chamber depth is an inheritable trait which is affected by age, gender and race. Over 30 years ago, Alsbirk proposed that the shallow anterior chamber, which was typical of the Greenlandic Inuit, and which brings the iris in proximity to the cornea, may have evolved as a thermoregulatory adaptation to resist corneal freezing. Here, this hypothesis is revisited. Recent population genetic data which provide evidence for migration patterns of early humans are discussed and the notions of natural selection and ocular adaptation to cold climates are considered. Problems with the hypothesis are examined, but the idea that the shallow anterior chamber has a thermoregulatory role appears sound and suggests that shallow anterior chambers may have evolved in Homo sapiens living in north-east Asia during the last Ice Age.
Notes
Comment In: Clin Experiment Ophthalmol. 2008 Jan-Feb;36(1):3-418290946
PubMed ID
18290957 View in PubMed
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Assessment of cold stress in outdoor work.

https://arctichealth.org/en/permalink/ahliterature51684
Source
Arctic Med Res. 1994 Jan;53(1):40-8
Publication Type
Article
Date
Jan-1994
Author
H. Anttonen
H. Virokannas
Author Affiliation
Oulu Regional Institute of Occupational Health, Finland.
Source
Arctic Med Res. 1994 Jan;53(1):40-8
Date
Jan-1994
Language
English
Publication Type
Article
Keywords
Adult
Body Temperature Regulation - physiology
Cold Climate
Humans
Male
Occupational Exposure
Occupations
Stress - physiopathology
Temperature Sense - physiology
Abstract
The evaluation of cold stress in working life was done in 13, mainly outdoor, occupations and 143 workers using local temperatures, body cooling and thermal sensations. The subjects in the study were young, healthy men and they wore the type of winter clothing generally used in those ambient temperatures (+6...-29 degrees C), for in a work load of from 112 to 480 W. Local temperatures on finger skin indicated that manual dexterity was often reduced in outdoor work. A risk of frostbite was frequently found on the cheek and the wind chill index predicted the risk quite well. Body cooling was often temporarily too high when measured by heat debt and mean skin temperature. Thermal sensations were cool or cold occasionally in 28% of the workers interviewed. The insulation of clothing worn was often lower than the IREQmin-value recommends. The results showed that in outdoor work in winter time cold stress frequently reduced (70%) working ability at least for a short period. Mean skin temperature seems to be, in practice, a useful indicator for body cooling and the IREQmin-value was suitable, especially in light work, to indicate body cooling. A very sensitive factor for the expression of cold stress was finger temperature, at least as an indicator of finger dexterity. Due to the adverse health effects found the cold stress should also be evaluated more systematically in occupational health and safety with health examinations, with protective clothing and technical preventive means.
PubMed ID
8049001 View in PubMed
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BrĂ¼nnich's guillemots (Uria lomvia) maintain high temperature in the body core during dives.

https://arctichealth.org/en/permalink/ahliterature78670
Source
Comp Biochem Physiol A Mol Integr Physiol. 2007 Jun;147(2):438-44
Publication Type
Article
Date
Jun-2007
Author
Niizuma Yasuaki
Gabrielsen Geir W
Sato Katsufumi
Watanuki Yutaka
Naito Yasuhiko
Author Affiliation
Japan Society for the Promotion of Science, Hokkaido National Fisheries Research Institute, Kushiro 085-0802, Japan. niizuma@ccmfs.meijo-u.ac.jp
Source
Comp Biochem Physiol A Mol Integr Physiol. 2007 Jun;147(2):438-44
Date
Jun-2007
Language
English
Publication Type
Article
Keywords
Animals
Body Temperature Regulation - physiology
Charadriiformes - physiology
Diving - physiology
Rest
Abstract
A major challenge for diving birds, reptiles, and mammals is regulating body temperature while conserving oxygen through a reduction in metabolic processes. To gain insight into how these needs are met, we measured dive depth and body temperatures at the core or periphery between the skin and abdominal muscles simultaneously in freely diving Brünnich's guillemots (Uria lomvia), an arctic seabird, using an implantable data logger (16-mm diameter, 50-mm length, 14-g mass, Little Leonardo Ltd., Tokyo). Guillemots exhibited increased body core temperatures, but decreased peripheral temperatures, during diving. Heat conservation within the body core appeared to result from the combined effect of peripheral vasoconstriction and a high wing beat frequency that generates heat. Conversely, the observed tissue hypothermia in the periphery should reduce metabolic processes as well as heat loss to the water. These physiological effects are likely one of the key physiological adaptations that makes guillemots to perform as an efficient predator in arctic waters.
PubMed ID
17321772 View in PubMed
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Calculation of mean skin temperature and changes in body heat content during paediatric anaesthesia.

https://arctichealth.org/en/permalink/ahliterature35802
Source
Br J Anaesth. 1994 May;72(5):548-53
Publication Type
Article
Date
May-1994
Author
K. Puhakka
H. Anttonen
J. Niskanen
P. Ryhänen
Author Affiliation
Department of Anaesthesiology, Oulu University Central Hospital, Finland.
Source
Br J Anaesth. 1994 May;72(5):548-53
Date
May-1994
Language
English
Publication Type
Article
Keywords
Anesthesia, General
Body Temperature Regulation - physiology
Child
Child, Preschool
Humans
Infant
Mathematics
Reference Values
Research Support, Non-U.S. Gov't
Skin Temperature - physiology
Abstract
Mean skin temperature and changes in body heat content were calculated in several different ways from measurements made in five children during operation. Mean skin temperatures were calculated from 162 sets of measurements using 15, 12, eight, seven and four skin sites with various formulae modified according to age. The results of other formulae were compared with age-adjusted, area-weighted 15-site mean skin temperature which was used as a reference. Changes in body heat content were calculated from Burton's equation in different ways and errors from different variables in the formula were evaluated. Mean skin temperature from 12 skin sites was within 0.5 degrees C of the 15-point reference method, and that from four sites within 1 degree C. The core temperature selected and the weighting coefficients used in calculating mean body temperature were more important sources of error in the determination of change in body heat content than was mean skin temperature.
PubMed ID
8198907 View in PubMed
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Cardiac and thermal homeostasis in the aging Brown Norway rat.

https://arctichealth.org/en/permalink/ahliterature90545
Source
J Gerontol A Biol Sci Med Sci. 2008 Dec;63(12):1307-13
Publication Type
Article
Date
Dec-2008
Author
Gordon Christopher J
Author Affiliation
United States Environmental Protection Agency, Research Triangle Park, NC 27711, USA. gordon.christopher@epa.gov
Source
J Gerontol A Biol Sci Med Sci. 2008 Dec;63(12):1307-13
Date
Dec-2008
Language
English
Publication Type
Article
Keywords
Aging - physiology
Animals
Body Temperature Regulation - physiology
Heart Rate - physiology
Homeostasis - physiology
Male
Models, Animal
Motor Activity - physiology
Rats
Rats, Inbred BN
Telemetry
Abstract
The cardiovascular and thermoregulatory systems are considered to be susceptible in the aged population, but little is known about baseline cardiac and thermoregulatory homeostasis in rodent models of aging. Radiotransmitters were implanted in male, Brown Norway rats obtained at 4, 12, and 24 months to monitor the electrocardiogram (ECG), interbeat interval (IBI), heart rate (HR), core temperature (Tc), and motor activity (MA). There was no significant effect of age on resting HR and MA. Daytime Tc of the 24-month-old rats was significantly elevated above those of the 4- and 12-month-old groups. Variability of the IBI was highest in the 24-month-old rats. The elevation in daytime Tc beginning around 8 months of age may be a physiological biomarker of aging and may be an important factor to consider in studies using caloric restriction-induced hypothermia to increase longevity.
PubMed ID
19126843 View in PubMed
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Changes in aggressive behavior, thermoregulation, and endocrine responses in BALB/cLac and C57Bl/6J mice under cold exposure.

https://arctichealth.org/en/permalink/ahliterature11761
Source
Physiol Behav. 1993 Mar;53(3):535-8
Publication Type
Article
Date
Mar-1993
Author
M P Moshkin
M A Potapov
O F Frolova
V I Evsikov
Author Affiliation
Biological Institute, Siberian Branch of Russia's Academy of Sciences, Novosibirsk.
Source
Physiol Behav. 1993 Mar;53(3):535-8
Date
Mar-1993
Language
English
Publication Type
Article
Keywords
11-Hydroxycorticosteroids - blood
Acclimatization - physiology
Aggression - physiology
Agonistic Behavior - physiology
Animals
Body Temperature Regulation - physiology
Comparative Study
Energy Metabolism - physiology
Glucocorticoids - blood
Male
Mice
Mice, Inbred BALB C
Mice, Inbred C57BL
Norepinephrine - physiology
Species Specificity
Testosterone - blood
Abstract
Effect of cold exposure on aggressive behavior, on the concentrations of testosterone and glucocorticoids, as well as on the oxygen consumption at different ambient temperatures, and calorigenic effect of noradrenaline have been studied in BALB/cLac and C57Bl/6J males. Under normal temperature conditions, there have been no significant interstrain differences. After cold exposure (5 weeks at 6-8 degrees C), C57Bl/6J mice exhibited more pronounced adaptive changes in thermoregulation and endocrine status (increase of glucocorticoids and decrease of testosterone concentrations were less expressed in C57Bl/6J than in BALB/cLac). At the same time, males of this strain demonstrated more intensive aggression than BALB/cLac mice. Some relations between physiological and behavioral changes caused by cold exposure are discussed.
PubMed ID
8451320 View in PubMed
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Changes in cold tolerance due to a 14-day stay in the Canadian Arctic.

https://arctichealth.org/en/permalink/ahliterature210669
Source
Int J Biometeorol. 1996 Nov;39(4):182-6
Publication Type
Article
Date
Nov-1996
Author
S D Livingstone
T. Romet
A A Keefe
R W Nolan
Author Affiliation
Defence and Civil Institute of Environmental Medicine, North York, Ontario, Canada.
Source
Int J Biometeorol. 1996 Nov;39(4):182-6
Date
Nov-1996
Language
English
Publication Type
Article
Keywords
Acclimatization - physiology
Adult
Arctic Regions
Body Temperature Regulation - physiology
Canada
Case-Control Studies
Cold Climate
Humans
Male
Time Factors
Abstract
Response to cold exposure tests both locally and of the whole body were examined in subjects who stayed in the arctic (average maximum and minimum temperatures -11 and -21 degrees C respectively) for 14 days of skiing and sleeping in tents. These changes were compared to responses in subjects living working in Ottawa, Canada (average max. and min. temperatures -5 and -11 degrees C respectively). The tests were done before the stay in the Arctic (Pre), immediately after the return (Post 1) and approximately 32 days after the return (Post 2). For the whole-body cold exposure each subject, wearing only shorts and lying on a rope mesh cot, was exposed to an ambient temperature of 10 degrees C. There was no consistent response in the changes of metabolic or body temperature to this exposure in either of groups and, in addition, the changes over time were variable. Cold induced vasodilatation (CIVD) was determined by measuring temperature changes in the middle finger of the nondominant hand upon immersion in ice water for 30 min. CIVD was depressed after the Arctic exposure whilst during the Post 2 testing, although variable, did not return to the Pre values; the responses of the control group were similar. These results indicate that normal seasonal changes may be as important in adaptation as a stay in the Arctic. Caution is advised in the separation of seasonal effects when examining the changes in adaptation after exposure to a cold environment.
PubMed ID
9008430 View in PubMed
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Climate variations and the physiological basis of temperature dependent biogeography: systemic to molecular hierarchy of thermal tolerance in animals.

https://arctichealth.org/en/permalink/ahliterature95934
Source
Comp Biochem Physiol A Mol Integr Physiol. 2002 Aug;132(4):739-61
Publication Type
Article
Date
Aug-2002
Author
Pörtner H O
Author Affiliation
Alfred-Wegener-Institut für Polar- und Meeresforschung, Okophysiologie, Postfach 12 01 61, D-27515 Bremerhaven, Germany. hpoertner@awi-bremerhaven.de
Source
Comp Biochem Physiol A Mol Integr Physiol. 2002 Aug;132(4):739-61
Date
Aug-2002
Language
English
Publication Type
Article
Keywords
Acclimatization - physiology
Aerobiosis
Animals
Body Temperature Regulation - physiology
Climate
Cold Climate
Marine Biology
Mitochondria - metabolism
Oxygen - physiology
Respiratory Physiological Phenomena
Abstract
The physiological mechanisms limiting and adjusting cold and heat tolerance have regained interest in the light of global warming and associated shifts in the geographical distribution of ectothermic animals. Recent comparative studies, largely carried out on marine ectotherms, indicate that the processes and limits of thermal tolerance are linked with the adjustment of aerobic scope and capacity of the whole animal as a crucial step in thermal adaptation on top of parallel adjustments at the molecular or membrane level. In accordance with Shelford's law of tolerance decreasing whole animal aerobic scope characterises the onset of thermal limitation at low and high pejus thresholds (pejus=getting worse). The drop in aerobic scope of an animal indicated by falling oxygen levels in the body fluids and or the progressively limited capacity of circulatory and ventilatory mechanisms. At high temperatures, excessive oxygen demand causes insufficient oxygen levels in the body fluids, whereas at low temperatures the aerobic capacity of mitochondria may become limiting for ventilation and circulation. Further cooling or warming beyond these limits leads to low or high critical threshold temperatures (T(c)) where aerobic scope disappears and transition to an anaerobic mode of mitochondrial metabolism and progressive insufficiency of cellular energy levels occurs. The adjustments of mitochondrial densities and their functional properties appear as a critical process in defining and shifting thermal tolerance windows. The finding of an oxygen limited thermal tolerance owing to loss of aerobic scope is in line with Taylor's and Weibel's concept of symmorphosis, which implies that excess capacity of any component of the oxygen delivery system is avoided. The present study suggests that the capacity of oxygen delivery is set to a level just sufficient to meet maximum oxygen demand between the average highs and lows of environmental temperatures. At more extreme temperatures only time limited passive survival is supported by anaerobic metabolism or the protection of molecular functions by heat shock proteins and antioxidative defence. As a corollary, the first line of thermal sensitivity is due to capacity limitations at a high level of organisational complexity, i.e. the integrated function of the oxygen delivery system, before individual, molecular or membrane functions become disturbed. These interpretations are in line with the more general consideration that, as a result of the high level of complexity of metazoan organisms compared with simple eukaryotes and then prokaryotes, thermal tolerance is reduced in metazoans. A similar sequence of sensitivities prevails within the metazoan organism, with the highest sensitivity at the organismic level and wider tolerance windows at lower levels of complexity. However, the situation is different in that loss in aerobic scope and progressive hypoxia at the organismic level define the onset of thermal limitation which then transfers to lower hierarchical levels and causes cellular and molecular disturbances. Oxygen limitation contributes to oxidative stress and, finally, denaturation or malfunction of molecular repair, e.g. during suspension of protein synthesis. The sequence of thermal tolerance limits turns into a hierarchy, ranging from systemic to cellular to molecular levels.
PubMed ID
12095860 View in PubMed
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Clinical trial of a novel surface cooling system for fever control in neurocritical care patients.

https://arctichealth.org/en/permalink/ahliterature5758
Source
Crit Care Med. 2004 Dec;32(12):2508-15
Publication Type
Article
Date
Dec-2004
Author
Stephan A Mayer
Robert G Kowalski
Mary Presciutti
Noeleen D Ostapkovich
Elaine McGann
Brian-Fred Fitzsimmons
Dileep R Yavagal
Y Evelyn Du
Andrew M Naidech
Nazli A Janjua
Jan Claassen
Kurt T Kreiter
Augusto Parra
Christopher Commichau
Author Affiliation
Neurological Intensive Care Unit, Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA. sam@columbia.edu
Source
Crit Care Med. 2004 Dec;32(12):2508-15
Date
Dec-2004
Language
English
Publication Type
Article
Keywords
Adult
Aged
Body Temperature Regulation - physiology
Brain Injuries - complications - diagnosis
Chi-Square Distribution
Comparative Study
Critical Care - methods
Critical Illness
Equipment Design
Equipment Safety
Female
Fever - etiology - mortality - therapy
Follow-Up Studies
Humans
Hypothermia, Induced - instrumentation - methods
Intensive Care Units
Male
Middle Aged
Probability
Prospective Studies
Research Support, Non-U.S. Gov't
Risk assessment
Single-Blind Method
Statistics, nonparametric
Treatment Outcome
Abstract
OBJECTIVE: To compare the efficacy of a novel water-circulating surface cooling system with conventional measures for treating fever in neuro-intensive care unit patients. DESIGN: Prospective, unblinded, randomized controlled trial. SETTING: Neurologic intensive care unit in an urban teaching hospital. PATIENTS: Forty-seven patients, the majority of whom were mechanically ventilated and sedated, with fever > or =38.3 degrees C for >2 consecutive hours after receiving 650 mg of acetaminophen. INTERVENTIONS: Subjects were randomly assigned to 24 hrs of treatment with a conventional water-circulating cooling blanket placed over the patient (Cincinnati SubZero, Cincinnati OH) or the Arctic Sun Temperature Management System (Medivance, Louisville CO), which employs hydrogel-coated water-circulating energy transfer pads applied directly to the trunk and thighs. MEASUREMENTS AND MAIN RESULTS: Diagnoses included subarachnoid hemorrhage (60%), cerebral infarction (23%), intracerebral hemorrhage (11%), and traumatic brain injury (4%). The groups were matched in terms of baseline variables, although mean temperature was slightly higher at baseline in the Arctic Sun group (38.8 vs. 38.3 degrees C, p = .046). Compared with patients treated with the SubZero blanket (n = 24), Arctic Sun-treated patients (n = 23) experienced a 75% reduction in fever burden (median 4.1 vs. 16.1 C degrees -hrs, p = .001). Arctic Sun-treated patients also spent less percent time febrile (T > or =38.3 degrees C, 8% vs. 42%, p
Notes
Comment In: Crit Care Med. 2004 Dec;32(12):2558-6015599175
Comment In: Crit Care Med. 2005 Aug;33(8):1890-1; author reply 189116096487
Comment In: Crit Care Med. 2005 Jul;33(7):167216003098
PubMed ID
15599159 View in PubMed
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[Comparative evaluation of various physiological indicators of the heat-protecting properties of clothing].

https://arctichealth.org/en/permalink/ahliterature227551
Source
Gig Tr Prof Zabol. 1991;(8):6-8
Publication Type
Article
Date
1991
Author
R F Afanas'eva
L A Basargina
Iu Khassi
N. Antonen
N. Rintamiaki
Source
Gig Tr Prof Zabol. 1991;(8):6-8
Date
1991
Language
Russian
Publication Type
Article
Keywords
Body surface area
Body Temperature Regulation - physiology
Clothing - standards
Finland
Hot Temperature
Humans
Microclimate
Skin Temperature - physiology
Thermal Conductivity
Time Factors
USSR
United States
Abstract
The article provides a comparative analysis of different techniques for determining weight-average temperatures of the skin (ts) and heat-stream temperatures (qt) from the body surface to calculate the thermal resistance of clothes. Issues related to quantitative inconsistencies among different techniques and ways to avoid them are also discussed.
PubMed ID
1794710 View in PubMed
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63 records – page 1 of 7.