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  • 1
    Publication Date: 2012-04-13
    Description: Understanding the molecular and cellular mechanisms that mediate magnetosensation in vertebrates is a formidable scientific problem. One hypothesis is that magnetic information is transduced into neuronal impulses by using a magnetite-based magnetoreceptor. Previous studies claim to have identified a magnetic sense system in the pigeon, common to avian species, which consists of magnetite-containing trigeminal afferents located at six specific loci in the rostral subepidermis of the beak. These studies have been widely accepted in the field and heavily relied upon by both behavioural biologists and physicists. Here we show that clusters of iron-rich cells in the rostro-medial upper beak of the pigeon Columbia livia are macrophages, not magnetosensitive neurons. Our systematic characterization of the pigeon upper beak identified iron-rich cells in the stratum laxum of the subepidermis, the basal region of the respiratory epithelium and the apex of feather follicles. Using a three-dimensional blueprint of the pigeon beak created by magnetic resonance imaging and computed tomography, we mapped the location of iron-rich cells, revealing unexpected variation in their distribution and number--an observation that is inconsistent with a role in magnetic sensation. Ultrastructure analysis of these cells, which are not unique to the beak, showed that their subcellular architecture includes ferritin-like granules, siderosomes, haemosiderin and filopodia, characteristics of iron-rich macrophages. Our conclusion that these cells are macrophages and not magnetosensitive neurons is supported by immunohistological studies showing co-localization with the antigen-presenting molecule major histocompatibility complex class II. Our work necessitates a renewed search for the true magnetite-dependent magnetoreceptor in birds.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Treiber, Christoph Daniel -- Salzer, Marion Claudia -- Riegler, Johannes -- Edelman, Nathaniel -- Sugar, Cristina -- Breuss, Martin -- Pichler, Paul -- Cadiou, Herve -- Saunders, Martin -- Lythgoe, Mark -- Shaw, Jeremy -- Keays, David Anthony -- England -- Nature. 2012 Apr 11;484(7394):367-70. doi: 10.1038/nature11046.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institute of Molecular Pathology, Dr Bohr-Gasse, 1030 Vienna, Austria.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22495303" target="_blank"〉PubMed〈/a〉
    Keywords: Animal Migration ; Animals ; Beak/anatomy & histology/*cytology ; Columbidae/*anatomy & histology/physiology ; Feathers/cytology/ultrastructure ; Ferrocyanides/analysis ; Immunohistochemistry ; Iron/analysis/*metabolism ; Macrophages/*metabolism/ultrastructure ; *Magnetic Fields ; Magnetic Resonance Imaging ; Neurons/metabolism ; Orientation ; Respiratory Mucosa/cytology/ultrastructure ; *Sensation ; Tomography, Emission-Computed, Single-Photon
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 2
    ISSN: 1432-1076
    Keywords: Erythropoietin ; Erythropoesis ; Iron status ; Inflamination ; Postoperative anaemia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The aim of our study was to evaluate bone marrow stimulation and bone marrow response to post-operative anaemia in children after open heart surgery. In 16 children (age 5.7±0.9 years, weight 20.1±3.2 kg) serum erythropoietin, haematocrit, reticulocyte count, ferritin, transferrin saturation and C-reactive protein were assessed perioperatively after cardiopumonary bypass for surgical repair of atrial septal defect. Erythropoietin increased seven fold from 14±6.2 (7–30) to 80±49 (20–171) mU/ml (P〈0.05) and the reticulocyte count a 1.7-fold from 11.1±3.1 (6–19) to 18.4±5.9 (10–31) ‰ (P〈0.05). Transferrin saturation was inversely correlated to C-reactive protein. Conclusion These findings suggest adequate bone marrow stimulation but an inadequate bone marrow response during the immediate perioperative period, caused by inhibition of erythropoesis by acute postoperative inflammation in children after open heart surgery.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-1076
    Keywords: Key words Erythropoietin ; Erythropoesis ; Iron status ; Inflammation ; Postoperative anaemia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The aim of our study was to evaluate bone marrow stimulation and bone marrow response to postoperative anaemia in children after open heart surgery. In 16 children (age 5.7 ± 0.9 years, weight 20.1 ± 3.2 kg) serum erythropoietin, haematocrit, reticulocyte count, ferritin, transferrin saturation and C-reactive protein were assessed perioperatively after cardiopumonary bypass for surgical repair of atrial septal defect. Erythropoietin increased seven fold from 14 ± 6.2 (7–30) to 80 ± 49 (20–171) mU/ml (P 〈 0.05) and the reticulocyte count a 1.7-fold from 11.1 ± 3.1 (6–19) to 18.4 ± 5.9 (10–31) ‰ (P 〈 0.05). Transferrin saturation was inversely correlated to C-reactive protein. Conclusion These findings suggest adequate bone marrow stimulation but an inadequate bone marrow response during the immediate perioperative period, caused by inhibition of erythropoesis by acute postoperative inflammation in children after open heart surgery.
    Type of Medium: Electronic Resource
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