Browsing by Subject "Stromal cell"

Now showing 1 - 3 of 3
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    Pathology, genetics and cell biology of hemangioblastomas
    (Murcia : F. Hernández, 1996) Wizigmann-Voos, S.; Plate, K.H.
    Hemangioblastomas are highly vascularized tumors of not well-defined histological origin which are frequently associated with cysts. They arise preferentially in cerebellum, medulla and spinal cord and are histologically indistinguishable from vascular lesions in the retina (so-called angiomatosis retinae). Hemangioblastomas are the most frequent manifestations of the von Hippel-Lindau (VHL) disease, an autosomaldominant inherited cancer syndrome but also occur as sporadic non-hereditary tumors. The VHL tumor suppressor gene has recently been cloned and enormous progress has been made towards the understanding of molecular biology and biological function of the VHL gene. Germline mutations in VHL patients, as well as somatic mutations in different tumors, including hemangioblastomas, have been identified, its ability to act as a tumor suppressor in vivo has been confirmed, and interaction with transcription factors Elongin B and C leading to inhibition of transcriptional elongation has been demonstrated. The mechanism underlying neovascularization and cyst formation in hemangioblastomas and how this is linked to inactivation of the VHL tumor suppressor gene is not known. However, the finding of dramatic up-regulation of vascular endothelial growth factor (VEGF), a potent endothelial cell growth factor with vascular permeability-inducing activity, in stromal cells and the corresponding receptors, VEGFR-1 and VEGFR-2, in tumor endothelial cells suggests that angiogenesis and cyst formation in hemangioblastomas may be regulated by this signaling pathway via a paracrine mechanism.
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    Telocytes, a distinct type of cell among the stromal cells present in the lamina propria of jejunum
    (F. Hernández y Juan F. Madrid. Universidad de Murcia. Departamento de Biología Celular e Histología, 2012) Cretoiu, D.; Cretoiu, Sanda M.; Simionescu, Anca A.; Popescu, L.M.
    Conventionally, cells described in the stroma of the intestinal wall are fibroblasts/fibrocytes, mast cells, plasma cells, eosinophils, macrophages and, interstitial cells of Cajal (ICCs), the latter being considered as the pacemakers of gastrointestinal rhythmicity. Recently, a new type of stromal cell called telocyte (TCs) was found in various cavitary and non-cavitary organs (www.telocytes.com). We show here direct electron microscopical evidence for the presence of TCs in the lamina propria of rat jejunum just beneath the epithelial layer of the mucosal crypts and in between the smooth muscle cells (SMCs) of muscularis mucosae. TCs are characterized by: several very long (tens to hundreds of µm) prolongations called telopodes (Tps). Tps (with caliber below the resolving power of light microscopy) display podomeres (thin segments ≤0.2 µm) and podoms (dilations accommodating caveolae, mitochondria, and endoplasmic reticulum). Tps present dichotomous branching and form a three dimensional network close to immune cells, SMCs or nerve bundles. TCs could play a role in intercellular signaling and control of local tissue homeostasis
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    The disappearance of CD34-positive and alpha-smooth muscle actin-positive stromal cells associated with human intra-uterine and tubal pregnancies
    (Murcia : F. Hernández, 2004) Kuroda, Naoto; Miyazaki, E.; Hayashi, Yoshihiro; Toi, M.; Hiroi, Makoto; Enzan, H.
    In order to elucidate the change in alphasmooth muscle actin (ASMA)-positive and CD34- positive stromal cells associated with pregnancy, we examined endometrial and Fallopian tube tissues from 40 patients including normal endometrium (n=10), intrauterine pregnancy (n=10), normal Fallopian tube (n=10), and tubal pregnancy (n=10), using immunohistochemistry. In normal endometrium, only a few ASMApositive cells were focally observed. Additionally, a wide range of CD34-positive stromal cell abundance was observed. In normal Fallopian tube mucosa, a small to moderate number of both ASMA-positive and CD34- positive stromal cells was observed. Neither ASMApositive nor CD34-positive stromal cells were observed anywhere in the decidual stroma during both intrauterine and tubal pregnancies. Likewise, a varying abundance of ASMA-positive cells but no CD34- positive stromal cells were observed at the fetal side during both intra-uterine and tubal pregnancies. In conclusion, the disappearance of CD34-positive and ASMA-positive stromal cells may be an indicator of decidualisation induced change in the stroma during both intra-uterine and tubal pregnancies. ASMA-positive stromal cells at the fetal side associated with pregnancy may play a role in the production of villous extracellular matrix or regulation of blood flow.