ABSTRACT
Homology PCR has been used to identify receptor tyrosine kinases (RTKs) expressed during activation of rat hepatic stellate cells, the key fibrogenic mesenchymal element in the liver. Partial cDNAs encoding several RTKs were cloned from stellate cells activated in vivo, including those of Flt-1, Flk-1, c-met, PDGFR, and Tyro10/DDR2. RNAse protection from cells activated in vivo demonstrated biphasic induction of flt-1 and flk-1 mRNAs, receptors for vascular endothelial growth factor (VEGF). Culture-activation of stellate cells was associated with increased [125I]VEGF binding and Flt-1 and Flk-1 receptor protein. Induction of VEGF binding sites correlated with an 2.5-fold increase in DNA synthesis in response to VEGF, but only if cells were activated by growth on collagen 1, whereas cells maintained in a quiescent state on a basement membrane-like substratum (EHS matrix) were nonproliferative. In both stellate and endothelial cells VEGF-induced mitogenesis was augmented by co-incubation with basic fibroblast growth factor (bFGF), a cytokine with known synergy with VEGF. These findings suggest that the cellular targets of VEGF in liver may not be confined to sinusoidal endothelial cells, and that VEGF responses reflect combined effects on both hepatic stellate cells and sinusoidal endothelium.
Subject(s)
Liver/enzymology , Receptor Protein-Tyrosine Kinases/metabolism , Receptors, Growth Factor/metabolism , Wound Healing , Animals , Base Sequence , Binding Sites , Cells, Cultured , Cloning, Molecular , DNA, Complementary , Enzyme Induction , Extracellular Matrix/metabolism , Iodine Radioisotopes , Liver/cytology , Mesoderm , Molecular Sequence Data , Polymerase Chain Reaction , Rats , Rats, Sprague-Dawley , Receptor Protein-Tyrosine Kinases/genetics , Receptors, Growth Factor/genetics , Receptors, Vascular Endothelial Growth FactorABSTRACT
We successfully used high-density vitreous substitutes to remove four dislocated crystalline lenses and three dislocated intraocular lenses (IOLs) from the vitreous cavity. Fluorosilicone oil (300 cs) was used to remove the four lenses and one of the IOLs. Perfluorophenanthrene (Vitreon) was used to remove the other two dislocated IOLs. The dislocated lenses or IOLs were floated by the high-density vitreous substitutes and removed safely without damaging the retina; there were no intraoperative complications. Postoperative residual fluorosilicone oil droplets were found in one case.
