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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    European journal of applied physiology 77 (1997), S. 149-156 
    ISSN: 1439-6327
    Keywords: Key words Hyperthermia ; Hormones ; Growth hormone ; Immunology ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This study was designed to test the hypothesis that the immune changes seen during in vivo whole body hyperthermia are mediated by elevations in the plasma concentrations of either catecholamines, growth hormone or β-endorphins. Eight healthy volunteers were immersed in a hot water bath (WI; water temperature 39.5°C) for 2 h during which their rectal temperature rose to 39.5°C. In a single blind, randomized, cross-over study the stress hormone effects were blocked one at a time by administration of propranolol, somatostatin or naloxone; the results were compared to those obtained during saline infusion (control). Blood samples were collected before, at the end of 2 h of WI (body temperature 39.5°C), and 2 h later. Hormone blockade did not abolish the hyperthermia-induced recruitment of natural killer (NK) cells to the blood, and no influence was observed on the percentages or concentrations of any other subpopulations of blood mononuclear cells, except that the number of cluster designation (CD)3+ cells slightly increased after hyperthermia only in the propranolol experiment. Furthermore, the NK cell activity, both unstimulated and interferon-α or interleukin-2 stimulated, did not differ from the control situation. It is of interest, however, that somatostatin partly abolished the hyperthermia induced increase in the neutrophil number. Based on these data and previous results showing that growth hormone infusion increases the concentration of neutrophils in the blood, it is suggested that growth hormone is at least partly responsible for hyperthermia induced neutrocytosis.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1439-6327
    Keywords: Key words Natural killer cells ; β-endorphin ; Catecholamines ; T cells ; Aviation medicine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To evaluate a possible role for β-endorphin in the stress-induced modulation of natural killer (NK) cells, immunologically competent blood cells were followed in eight male volunteers administered either Naloxone or saline (control) during head-up tilt maintained until the appearance of presyncopal symptoms (PS). The PS appeared more rapidly with Naloxone compared to control [5.7 (SEM 1.1) vs 22.3 (SEM 5.1) min; P = 0.01]. The NK cell activity increased threefold during PS partly due to an increase in CD16+ and CD56+ NK cells in blood. In support, NK cell activity boosted with interferon-α and interleukin 2 rose in parallel with unboosted NK cell activity and NK cell concentration and activities returned to the baseline level after 105 min. The total lymphocyte count and the concentrations of CD3+, CD4+, CD8+, CD16+, and CD56+ cells increased during PS. Head-up tilt also induced an increase in plasma adrenaline concentration during control PS and a rise in plasma cortisol and adrenocorticotropic hormone concentrations up to 30 min thereafter, whereas no significant changes were found in plasma concentrations of noradrenaline, growth hormone, or β-endorphin. The results would indicate an influence of endorphin on the increase in plasma adrenaline concentration during head-up tilt and at the same time contra-indicate a significant role for adrenaline in the provocation of PS. The influence of head-up tilt on plasma β-endorphin was too small to influence the modulation of the cellular immune system.
    Type of Medium: Electronic Resource
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