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Growth Factor Alpha (growth + factor_alpha)
Selected AbstractsRestricted expression of Fgf16 within the developing chick inner earDEVELOPMENTAL DYNAMICS, Issue 8 2006Susan C. Chapman Abstract Fibroblast growth factor (FGF) signaling is required for otic placode induction and patterning of the developing inner ear. We have cloned the chick ortholog of Fgf16 and analyzed its expression pattern in the early chick embryo. Expression is restricted to the otic placode and developing inner ear through all the stages examined. By the closed otocyst stage, expression has resolved to anterior and posterior domains that partially overlap with those of bone morphogenetic protein 4 (Bmp4), a marker of the developing sensory patches, the cristae of the anterior and posterior semicircular canals. Platelet-derived growth factor alpha (PDGFA), another growth factor with restricted otic expression, also overlaps with Fgf16 expression. The restricted expression pattern of Fgf16 suggests a role for FGF signaling in the patterning of the sensory cristae, together with BMP signaling. Developmental Dynamics 235:2276,2281, 2006. © 2006 Wiley-Liss, Inc. [source] Influences of dopaminergic lesion on epidermal growth factor-ErbB signals in Parkinson's disease and its model: neurotrophic implication in nigrostriatal neuronsJOURNAL OF NEUROCHEMISTRY, Issue 4 2005Yuriko Iwakura Abstract Epidermal growth factor (EGF) is a member of a structurally related family containing heparin-binding EGF-like growth factor (HB-EGF) and transforming growth factor alpha (TGF,) that exerts neurotrophic activity on midbrain dopaminergic neurons. To examine neurotrophic abnormality in Parkinson's disease (PD), we measured the protein content of EGF, TGF,, and HB-EGF in post-mortem brains of patients with Parkinson's disease and age-matched control subjects. Protein levels of EGF and tyrosine hydroxylase were decreased in the prefrontal cortex and the striatum of patients. In contrast, HB-EGF and TGF, levels were not significantly altered in either region. The expression of EGF receptors (ErbB1 and ErbB2, but not ErbB3 or ErbB4) was down-regulated significantly in the same forebrain regions. The same phenomenon was mimicked in rats by dopaminergic lesions induced by nigral 6-hydroxydopamine infusion. EGF and ErbB1 levels in the striatum of the PD model were markedly reduced on the lesioned side, compared with the control hemisphere. Subchronic supplement of EGF in the striatum of the PD model locally prevented the dopaminergic neurodegeration as measured by tyrosine hydroxylase immunoreactivity. These findings suggest that the neurotrophic activity of EGF is maintained by afferent signals of midbrain dopaminergic neurons and is impaired in patients with Parkinson's disease. [source] Characterization of a comparative model of the extracellular domain of the epidermal growth factor receptorPROTEIN SCIENCE, Issue 2 2000Robert N. Jorissen Abstract The Epidermal Growth Factor (EGF) receptor is a tyrosine kinase that mediates the biological effects of ligands such as EGF and transforming growth factor alpha. An understanding of the molecular basis of its action has been hindered by a lack of structural and mutational data on the receptor. We have constructed comparative models of the four extracellular domains of the EGF receptor that are based on the structure of the first three domains of the insulin-like growth factor-1 (IGF-1) receptor. The first and third domains of the EGF receptor, L1 and L2, are right-handed beta helices. The second and fourth domains of the EGF receptor, S1 and S2, consist of the modules held together by disulfide bonds, which, except for the first module of the S1 domain, form rod-like structures. The arrangement of the L1 and S1 domains of the model are similar to that of the first two domains of the IGF-1 receptor, whereas that of the L2 and S2 domains appear to be significantly different. Using the EGF receptor model and limited information from the literature, we have proposed a number of regions that may be involved in the functioning of the receptor. In particular, the faces containing the large beta sheets in the L1 and L2 domains have been suggested to be involved with ligand binding of EGF to its receptor. [source] Evaluation of the effect of autologous mesenchymal stem cell injection in a large-animal model of bilateral kidney ischaemia reperfusion injuryCELL PROLIFERATION, Issue 3 2009L. Behr Objectives: Adult mesenchymal stem cells (MSC) have been proven to be of benefit to the kidney in different experimental models of renal injuries. All studies have been performed in valuable rodent models, but the relevance of these results to large mammals and ultimately, to humans remains unknown. Therefore, the aim of this study was to investigate the effect of MSC transplantation in an alternative ovine large-animal model of bilateral kidney ischaemia reperfusion injury. Material and methods: Sheep were divided into three groups: one sham-operated group and two groups submitted to renal bilateral ischaemia for 60 min. Animals with ischaemia reperfusion injury were treated with injection of autologous MSCs or with vehicle medium. Results: The model sheep presented with renal histological manefestations that closely resembled lesions seen in patients. Transplanted MSCs were found in glomeruli but not in tubules and did not express glomerular cell markers (podocin, von Willebrand factor), but functional evaluation showed no beneficial effect of MSC infusion. Morphological and molecular analyses corroborated the functional results. MSCs did not repair kidney parenchyma and failed to modulate cell death and proliferation or cytokine release (tumour necrosis factor-alpha, vascular endothelial growth factor alpha (VEGF-,), Bcl-2, caspase). Conclusion: In this unique autologous large-animal model, MSCs did not exhibit reparative or paracrine protective properties. [source] Erythema gyratum repens and acquired ichthyosis associated with transitional cell carcinoma of the kidneyCLINICAL & EXPERIMENTAL DERMATOLOGY, Issue 6 2001M. Ameen Both erythema gyratum repens (EGR) and acquired ichthyosis are distinctive dermatoses which have strong associations with internal malignancy. EGR usually precedes the diagnosis of malignancy whereas acquired ichthyosis commonly manifests after the detection of malignancy. We report a patient who initially presented with a figurate eruption of EGR which later developed into a widespread ichthyosis with disappearance of the serpiginous rash. Further investigations revealed an underlying transitional cell carcinoma of the kidney, an association which has not previously been reported with either EGR or acquired ichthyosis. The occurrence of two paraneoplastic skin disorders in the same patient may be explained by tumour cell secretion of transforming growth factor alpha, which has been shown to be mitogenic for keratinocytes. [source] | ||||||||||