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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
    Publication Date: 2011-06-10
    Description: A significant bottleneck in cardiovascular regenerative medicine is the identification of a viable source of stem/progenitor cells that could contribute new muscle after ischaemic heart disease and acute myocardial infarction. A therapeutic ideal--relative to cell transplantation--would be to stimulate a resident source, thus avoiding the caveats of limited graft survival, restricted homing to the site of injury and host immune rejection. Here we demonstrate in mice that the adult heart contains a resident stem or progenitor cell population, which has the potential to contribute bona fide terminally differentiated cardiomyocytes after myocardial infarction. We reveal a novel genetic label of the activated adult progenitors via re-expression of a key embryonic epicardial gene, Wilm's tumour 1 (Wt1), through priming by thymosin beta4, a peptide previously shown to restore vascular potential to adult epicardium-derived progenitor cells with injury. Cumulative evidence indicates an epicardial origin of the progenitor population, and embryonic reprogramming results in the mobilization of this population and concomitant differentiation to give rise to de novo cardiomyocytes. Cell transplantation confirmed a progenitor source and chromosome painting of labelled donor cells revealed transdifferentiation to a myocyte fate in the absence of cell fusion. Derived cardiomyocytes are shown here to structurally and functionally integrate with resident muscle; as such, stimulation of this adult progenitor pool represents a significant step towards resident-cell-based therapy in human ischaemic heart disease.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3696525/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3696525/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Smart, Nicola -- Bollini, Sveva -- Dube, Karina N -- Vieira, Joaquim M -- Zhou, Bin -- Davidson, Sean -- Yellon, Derek -- Riegler, Johannes -- Price, Anthony N -- Lythgoe, Mark F -- Pu, William T -- Riley, Paul R -- FS/08/004/23625/British Heart Foundation/United Kingdom -- G0700933/Medical Research Council/United Kingdom -- PG/10/005/28175/British Heart Foundation/United Kingdom -- RG/08/003/25264/British Heart Foundation/United Kingdom -- U01 HL100401/HL/NHLBI NIH HHS/ -- British Heart Foundation/United Kingdom -- England -- Nature. 2011 Jun 8;474(7353):640-4. doi: 10.1038/nature10188.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Molecular Medicine Unit, UCL Institute of Child Health, London WC1N 1EH, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21654746" target="_blank"〉PubMed〈/a〉
    Keywords: Adult Stem Cells/*cytology ; Animals ; *Cell Differentiation ; Cellular Reprogramming ; Gene Expression Regulation ; *Heart Injuries ; Mice ; Myocardial Infarction/pathology ; Myocytes, Cardiac/*cytology/metabolism ; Thymosin/metabolism ; WT1 Proteins/genetics/metabolism
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 3
    Publication Date: 2015-11-13
    Description: Animals have evolved homeostatic responses to changes in oxygen availability that act on different timescales. Although the hypoxia-inducible factor (HIF) transcriptional pathway that controls long-term responses to low oxygen (hypoxia) has been established, the pathway that mediates acute responses to hypoxia in mammals is not well understood. Here we show that the olfactory receptor gene Olfr78 is highly and selectively expressed in oxygen-sensitive glomus cells of the carotid body, a chemosensory organ at the carotid artery bifurcation that monitors blood oxygen and stimulates breathing within seconds when oxygen declines. Olfr78 mutants fail to increase ventilation in hypoxia but respond normally to hypercapnia. Glomus cells are present in normal numbers and appear structurally intact, but hypoxia-induced carotid body activity is diminished. Lactate, a metabolite that rapidly accumulates in hypoxia and induces hyperventilation, activates Olfr78 in heterologous expression experiments, induces calcium transients in glomus cells, and stimulates carotid sinus nerve activity through Olfr78. We propose that, in addition to its role in olfaction, Olfr78 acts as a hypoxia sensor in the breathing circuit by sensing lactate produced when oxygen levels decline.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4765808/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4765808/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Chang, Andy J -- Ortega, Fabian E -- Riegler, Johannes -- Madison, Daniel V -- Krasnow, Mark A -- K12 HL089989/HL/NHLBI NIH HHS/ -- MH065541/MH/NIMH NIH HHS/ -- NS069375/NS/NINDS NIH HHS/ -- P30 NS069375/NS/NINDS NIH HHS/ -- R01 MH065541/MH/NIMH NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2015 Nov 12;527(7577):240-4. doi: 10.1038/nature15721.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, Stanford University School of Medicine and Howard Hughes Medical Institute, Stanford, California 94305-5307, USA. ; Department of Medicine, Stanford University School of Medicine, Stanford, California 94305, USA. ; Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California 94305, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26560302" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Anoxia/genetics/metabolism ; Calcium Signaling ; Carotid Body/cytology/drug effects/metabolism ; Carotid Sinus/innervation ; Female ; HEK293 Cells ; Humans ; Hypercapnia/genetics/metabolism ; Lactic Acid/*metabolism/pharmacology ; Mice ; Olfactory Receptor Neurons/*metabolism ; Oxygen/blood/*metabolism ; Receptors, Odorant/deficiency/*metabolism ; *Respiration
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 4
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 59 (1988), S. 2220-2224 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A novel fluorescence microscope configuration for real-time observation of the Langmuir–Blodgett transfer is presented. It enables the imaging of any portion of the entire monolayer, including on the water subphase, on the substrate, or even on the meniscus. Studies are performed even while the layer is being deposited. Two sets of optical components, one for the visible and one for the ultraviolet spectrum, were implemented. Studies on a monolayer of dimyristoyl-L-α-phosphatidylethanolamine (DMPE) reveal domain growth and nucleation phenomena at the boundary between water-supported and deposited film. The performance of the instrument in the UV is demonstrated with pentadecanoic acid containing a pyrene probe.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0006-291X
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-1017
    Keywords: Protein/lipid interaction ; elastic membrane forces ; photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract The phase transitional behaviour of bilayers of the phospholipid l-α-ditridecanoylphos-phatidylcholine is studied as a function of protein content for the reaction center (RC) and an antenna protein (LHCP) of the bacterial photosynthetic apparatus. As membrane and protein are structurally well characterized the experimental results can be quantitatively compared with those of calculations based upon elastic models within the Landaude Gennes-theory. Agreement between theory and experiment demonstrates that dominant elastic forces result from a mismatch of hydrophobic regions of membrane and protein. The data also indicate that RC are present in a monomeric form and LHCP in a highly aggregated form. In addition, the latter protein responds to changes in the lipid environment.
    Type of Medium: Electronic Resource
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  • 7
    Publication Date: 2018-09-15
    Description: Purpose: The tumor microenvironment presents with altered extracellular matrix (ECM) and stroma composition, which may affect treatment efficacy and contribute to tissue stiffness. Ultrasound (US) elastography can visualize and quantify tissue stiffness noninvasively. However, the contributions of ECM and stromal components to stiffness are poorly understood. We therefore set out to quantify ECM and stroma density and their relation to tumor stiffness. Experimental Design: A modified clinical ultrasound system was used to measure tumor stiffness and perfusion during tumor growth in preclinical tumor models. In vivo measurements were compared with collagen mass spectroscopy and automatic analysis of matrix and stromal markers derived from immunofluorescence images. Results: US elastography estimates of tumor stiffness were positively correlated with tumor volume in collagen and myofibroblast-rich tumors, while no correlations were found for tumors with low collagen and myofibroblast content. US elastography measurements were strongly correlated with ex vivo mechanical testing and mass spectroscopy–based measurements of total collagen and immature collagen crosslinks. Registration of ultrasound and confocal microscopy data showed strong correlations between blood vessel density and T-cell density in syngeneic tumors, while no correlations were found for genetic tumor models. In contrast to collagen density, which was positively correlated with stiffness, no significant correlations were observed for hyaluronic acid density. Finally, localized delivery of collagenase led to a significant reduction in tumor stiffness without changes in perfusion 24 hours after treatment. Conclusions: US elastography can be used as a potential biomarker to assess changes in the tumor microenvironment, particularly changes affecting the ECM. Clin Cancer Res; 24(18); 4455–67. ©2018 AACR .
    Print ISSN: 1078-0432
    Electronic ISSN: 1557-3265
    Topics: Medicine
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