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  • 1
    Keywords: ANGIOGENESIS ; CELLS ; EXPRESSION ; GROWTH ; GROWTH-FACTOR ; BLOOD ; CELL ; ENDOTHELIAL GROWTH-FACTOR ; Germany ; GENE ; transcription ; DIFFERENTIATION ; EPITHELIA ; TRANSCRIPTION FACTOR ; INJECTION ; BIOLOGY ; MOUSE ; DISRUPTION ; inactivation ; COMPLEMENTATION ; EPITHELIAL-CELLS ; STRATEGIES ; RECEPTORS ; INSIGHTS ; VESSELS ; nude mice ; SUBSETS ; ARCHITECTURE ; LETHALITY ; MORPHOGENESIS ; targeting ; molecular ; thymus ; MOLECULAR-BASIS ; SUBSET ; ALLELE ; BLOOD-VESSELS ; gene targeting ; mesenchyme ; development ; ALLELES ; EPITHELIUM ; function ; branching ; nude mouse blastocyst complementation ; thymus development ; VASCULAR DEVELOPMENT ; vascular endothelial growth factor
    Abstract: The thymus harbors an organ-typical dense network of branching and anastomosing blood vessels. To address the molecular basis for morphogenesis of this thymus-specific vascular pattern, we have inactivated a key vascular growth factor, VEGF-A, in thymus epithelial cells (TECs). Both Vegf-A alleles were deleted in TECs by a complementation strategy termed nude mouse [mutated in the transcription factor Foxn1 (forkhead box N1)] blastocyst complementation. Injection of Foxn1(+/+) ES cells into Foxn1(nu/nu) blastocysts reconstituted a functional thymus. By dissecting thymus stromal cell subsets, we have defined, in addition to medullary TECs (mTECs) and cortical TECs (cTECs), another prominent stromal cell subset designated cortical mesenchymal cells (cMes). In chimeric thymi, mTECs and cTECs but not cMes were exclusively ES cell-derived. According to this distinct origin, the Vegf-A gene was deleted in mTECs and cTECs, whereas cMes still expressed Vegf-A. This genetic mosaic was associated with hypovascularization and disruption of the organ-typical network of vascular arcades. Thus, vascular growth factor production by TECs is required for normal thymus vascular architecture. These experiments provide insights into Foxn1-dependent and Foxn1-independent stromal cell development and demonstrate the value of this chimeric approach to analyzing gene function in thymus epithelium
    Type of Publication: Journal article published
    PubMed ID: 16027358
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  • 2
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    German Medical Science GMS Publishing House; Düsseldorf
    In:  Süddeutscher Kongress für Kinder- und Jugendmedizin; 63. Jahrestagung der Süddeutschen Gesellschaft für Kinder- und Jugendmedizin gemeinsam mit der Süddeutschen Gesellschaft für Kinderchirurgie und dem Berufsverband der Kinder- und Jugendärzte e.V. - Landesverband Baden-Württemberg; 20140425-20140426; Stuttgart/Fellbach; DOC14sgkjP23 /20140325/
    Publication Date: 2014-03-26
    Keywords: ddc: 610
    Language: German
    Type: conferenceObject
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  • 3
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    German Medical Science GMS Publishing House; Düsseldorf
    In:  DAV 2007; 25. Jahrestagung der deutschsprachigen Arbeitsgemeinschaft für Verbrennungsbehandlung; 20070110-20070113; St. Anton am Arlberg; DOC07dav20 /20080625/
    Publication Date: 2008-06-25
    Keywords: ddc: 610
    Language: German
    Type: conferenceObject
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  • 4
    Keywords: CELLS ; EXPRESSION ; CELL ; Germany ; GENE ; GENE-EXPRESSION ; ACCUMULATION ; LINES ; INFECTION ; DOMAIN ; T-CELL ; GLYCOPROTEIN ; virus ; gene expression ; LINE ; LYMPHOCYTES ; PHENOTYPE ; REPLICATION ; HUMAN-IMMUNODEFICIENCY-VIRUS ; VIRIONS ; ENVELOPE GLYCOPROTEIN ; TRANSMISSION ; GP41 CYTOPLASMIC TAIL ; MDCK CELLS ; SPREAD ; Type ; CELL-FREE ; ENV GENE-PRODUCT ; HTLV-I ; TYPE-1 MATRIX ; VIROLOGICAL SYNAPSE FORMATION
    Abstract: Background: Mutant HIV (HIV-Env-Tr712) lacking the cytoplasmic tail of the viral glycoprotein (Env-CT) exhibits a cell-type specific replication phenotype such that replicative spread occurs in some T-cell lines ( referred to as permissive cells) but fails to do so in most T-cell lines or in PBMCs ( referred to as non-permissive cells). We aim to gain insight on the underlying requirement for the Env-CT for viral spread in non-permissive cells. Results: We established that in comparison to HIV-Wt, both cell-free and cell-to-cell transmission of mutant HIV-Env-Tr712 from non-permissive cells were severely impaired under naturally low infection conditions. This requirement for Env-CT could be largely overcome by using saturating amounts of virus for infection. We further observed that in permissive cells, which supported both routes of mutant virus transmission, viral gene expression levels, Gag processing and particle release were inherently higher than in non-permissive cells, a factor which may be significantly contributing to their permissivity phenotype. Additionally, and correlating with viral transfer efficiencies in these cell types, HIV-Gag accumulation at the virological synapse ( VS) was reduced to background levels in the absence of the Env-CT in conjugates of non-permissive cells but not in permissive cells. Conclusions: During natural infection conditions, the HIV-Env-CT is critically required for viral transmission in cultures of non-permissive cells by both cell-free and cell-to-cell routes and is instrumental for Gag accumulation to the VS. The requirement of the Env-CT for these related processes is abrogated in permissive cells, which exhibit higher HIV gene expression levels
    Type of Publication: Journal article published
    PubMed ID: 20459872
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  • 5
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-0878
    Keywords: Lung, Bufo marinus ; Adrenergic innervation ; Neuroepithelial bodies ; Receptors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Neuroepithelial bodies (NEB) were identified in the lung of Bufo marinus. The characteristics of the cells and their innervation were studied with electron and fluorescence microscopy before and after close vagosympathetic denervation. The bodies consist of low columnar cells which rest on the epithelial basal lamina. The majority of the cells do not reach the lumen of the lung (basal cells); the few which do (apical cells) are bordered by microvilli and possess a single cilium. The neuroepithelial cell cytoplasm contains a variety of organelles the most characteristic of which are dense cored vesicles. Microspectrofluorometry and electron microscopic cytochemistry indicate significant quantities of 5-hydroxytryptamine in these cells. The neuroepithelial bodies could be divided into three groups on the basis of their innervation: 1) About 60% of the NEBs are innervated solely by nerve fibres containing agranular vesicles which form reciprocal synapses; 2) about 20% are innervated solely by adrenergic nerve fibres which form distinct synaptic contacts; and 3) the remaining 20% are innervated by both types of nerve fibres. It is proposed that the NEBs are receptors monitoring intrapulmonary PCO 2 and so leading to modulation of activity in afferent nerve fibres (type containing agranular vesicles). The presence of NEBs solely with an adrenergic (efferent) innervation poses a problem with this interpretation.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-0878
    Keywords: Pulmonary artery ; Bufo marinus (toad) ; Paraneurons ; Primary monoamines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pulmonary artery of Bufo marinus contains large numbers of bipolar cells situated in the tunica adventitia and in the outer layers of the media. These cells show a bright green-yellow fluorescence (emission spectra 485 nm) after formaldehyde pre-treatment suggesting that they contain a primary monoamine. The most characteristic fine-structural feature of these cells is the presence of numerous dense-cored vesicles (80—300 nm diameter) in their cytoplasm. The cells are in close contact (20 nm gap) with both agranular and granular nerve fibres. Both EM-cytochemical and formaldehyde-induced fluorescence tests indicate that the granule-containing nerve fibres are adrenergic. The agranular nerve fibres form discrete synaptic contacts with pre-and post-synaptic membrane thickenings on the cells. This was never observed with respect to the adrenergic fibres. Each process of the cells is about 45 μm long. The processes do not bear any special relationship to either vessels of the arterial vasa vasorum or medial smooth muscle cells. Their location in the wall of the artery suggests that they are functionally significant with respect to activity of the arterial media.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-0878
    Keywords: Neuroepithelial bodies ; Lungs ; Neuropeptide coexistence ; Neuropeptide immunocytochemistry ; Isoodon macrourus (Marsupialia)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The coexistence of serotonin and calcitonin gene-related peptide (CGRP) in neuroepithelial bodies of the bandicoot, Isoodon macrourus, has been examined using immunocytochemistry at the light- and electronmicroscope levels. The avidin-biotin technique of antigen localisation was used initially to identify serotonin-like and CGRP-like immunoreactivity (-LI). Serotonin-LI and CGRP-LI were found in neuroepithelial cells in the lungs of 30-day-old bandicoots. CGRP-LI could also be demonstrated in nerve fibres associated with some neuroepithelial bodies. The protein A-gold technique of antigen localisation was used to label neuroepithelial cells and nerve fibres at the subcellular level. Serotonin-LI and CGRP-LI were observed in the same dense-cored vesicles of most neuroepithelial cells; however, some neuroepithelial cells were shown to possess serotonin-LI without CGRP-LI. Nerve fibres immediately adjacent to neuroepithelial bodies exhibited mainly CGRP-LI. These results show that serotonin-LI and CGRP-LI are present in neuroepithelial cells of the bandicoot in the same secretory vesicles. This pattern of co-localisation may reflect co-ordinated or synergistic actions of these two neuroactive substances.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-0878
    Keywords: Anococcygeus muscle ; Innervation ; P-type nerves ; Purinergic nerves ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The innervation of the rat anococcygeus muscle has been investigated ultrastructurally following fixation with a modified chromaffin reaction for the demonstration of biogenic amines (Tranzer and Richards, 1976). Three types of nerve profiles were revealed: (1) 60–70 % of the profiles are adrenergic; (2) less than 5% of the profiles appear to be cholinergic; (3) up to 40% of the profiles are distinguished by the presence of a characteristically high proportion of electron-opaque, chromaffin-negative vesicles, 85–110nm in diameter. This third type of profile was not affected by 6-OHDA, and is considered to represent the non-adrenergic, non-cholinergic inhibitory innervation of this tissue. Because of the morphological similarity of this nerve type, apart from the smaller vesicle size, to classical peptidergic nerve endings, they have been termed “small p-type” (sp-type). These results are discussed in relation to a previous report describing only two types of nerve profiles in this tissue (Gillespie and Lüllmann-Rauch, 1974).
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-0878
    Keywords: Lung ; Bufo marinus ; Innervation ; Adrenergic nerves ; Neurosecretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The innervation of the toad (Bufo marinus) lung was studied with transmission electron microscopy and fluorescence techniques, both before and after 12 or 20 days close vagosympathetic denervation. Four cytologically distinct types of neuronal processes were recognised, in relation to the visceral muscles of the lung. These were described as cholinergic, adrenergic, nonadrenergic/non-cholinergic (NANC) and sensory on the basis of the characteristics of their vesicular content and cytochemical reactions. An apparent efferent innervation of visceral smooth muscle was achieved by NANC (50%), cholinergic (25%) and adrenergic (25%) fibres. A few sensory fibres were also present. After denervation only NANC fibres persisted, showing that the cell bodies of these fibres were intrapulmonary. The vascular smooth muscle was supplied by cholinergic, adrenergic and sensory fibres. In the walls of the proximal branches of the pulmonary artery were fibres containing large dense-cored vesicles. These profiles, which were associated with the vasa vasorum, were similar to neurosecretory fibres. After denervation all neural profiles associated with the vasculature had degenerated. The observations suggest that vagal vasodepressor effects in the toad lung are mediated indirectly through relaxation of visceral muscle strands which in their contracted state compress vascular channels.
    Type of Medium: Electronic Resource
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