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  • Key words Erythropoietin  (1)
  • Scanning electron microscopy  (1)
  • 1
    ISSN: 1439-6327
    Keywords: Key words Erythropoietin ; Carbon dioxide ; Haemoglobin oxygen affinity ; Human ; Hypoxia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  This study investigated the human erythropoietin (EPO) response to short-term hypocapnic hypoxia, its relationship to a normoxic or hypoxic increase of the haemoglobin oxygen affinity, and its suppression by the addition of CO2 to the hypoxic gas. On separate days, eight healthy male subjects were exposed to 2 h each of hypocapnic hypoxia, normocapnic hypoxia, hypocapnic normoxia, and normal breathing of room air (control experiment). During the control experiment, serum-EPO showed significant variations (ANOVA P=0.047) with a 15% increase in mean values. The serum-EPO measured in the other experiments were corrected for these spontaneous variations in each individual. At 2 h after ending hypocapnic hypoxia (10% O2 in nitrogen), mean serum-EPO increased by 28% [baseline 8.00 (SEM 0.84) U⋅1-1, post-hypoxia 10.24 (SEM 0.95) U⋅1-1, P=0.005]. Normocapnic hypoxia was produced by the addition of CO2 (10% Co2 with 10% O2) to the hypoxic gas mixture. This elicited an increased ventilation, unaltered arterial pH and haemoglobin oxygen affinity, a lower degree of hypoxia than during hypocapnic hypoxia, and no significant changes in serum-EPO (ANOVA P〉0.05). Hypocapnic normoxia, produced by hyperventilation of room air, elicited a normoxic increase in the haemoglobin oxygen affinity without changing serum-EPO. Among the measured blood gas and acid-base parameters, only the partial pressures of oxygen in arterial blood during hypocapnic hypoxia were related to the peak values of serum-EPO (r=−0.81, P=0.01). The present human EPO responses to hypoxia were lower than those which have previously been reported in rodents and humans. In contrast with the earlier rodent studies, it was found that human EPO production could not be triggered by short-term increases in pH and haemoglobin oxygen affinity per se, and the human EPO response to hypoxia could be suppressed by concomitant normocapnia without acidosis.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1530-0358
    Keywords: Collagen ; Colon ; Growth hormone ; Healing ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract PURPOSE: This experimental study was designed to investigate the collagen fibrils of colonic anastomoses in rats and to compare normal healing with rats treated with biosynthetic growth hormone (bGH). METHODS: The healing zone of left colonic anastomoses was studied at days 2, 4, and 6 after surgery by means of scanning electron microscopy. RESULTS: After four days of healing a normal anastomosis was filled with loosely packed and unorganized collagen fibrils, which were organized into collagen fibers after six days. Compared with normal anastomoses, rats treated with bGH showed a more organized healing, characterized by a dense structure of a new-formed collagen framework of fibrils and immature collagen fibers after four days and with bundles of new collagen fibers after six days. CONCLUSIONS: Healing colonic anastomoses are characterized by new-formed collagen fibrils at postoperative day 4, and bGH seems to stimulate structural organization of the anastomotic collagen fibrils into fibers.
    Type of Medium: Electronic Resource
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