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Electron transport in ferroelectric tunnel junctions (FTJs) with a three-step-like barrier combining a dielectric, ferromagnetic, and ferroelectric was investigated theoretically. A significant enhanced tunneling electroresistance effect was observed as compared to traditional FTJs with a bilayer composite barrier. The spin polarization also could be enhanced in a certain orientation of ferroelectric polarization. A metal/dielectric/ferromagnetic/ferroelectric/metal FTJ with a large ferromagnetic thickness is preferred for the optimal performance. The ferroelectricity in the ferroelectric layer has a weak modulation effect on the spin polarization. This work provides a way to enhance the performance of FTJs and/or to control the spin-polarized electronic transport by structure engineering. [ABSTRACT FROM AUTHOR]

Objectives: The function of netrin-1 in pathological angiogenesis and its role in retinal neovascularization were investigated in the retinas of oxygen-induced retinopathy (OIR) mice by inhibition of netrin-1. Methods: Expression of netrin-1 mRNA and protein in the retinas of OIR mice was analyzed by quantitative RT-PCR and immunoblotting. Inhibition of retinal neovascularization was achieved by lentivirus-mediated netrin-1 small hairpin RNA (shRNA) infection. Retinal neovascularization was examined by fluorescein angiography and quantification of preretinal neovascular nuclei in retinal sections. Results: Both mRNA and protein expression of netrin-1 were significantly upregulated in postnatal day 17 OIR mouse retinas. Treatment of OIR mice with specific lentivirus-mediated netrin-1 shRNA dramatically reduced neovascular outgrowth into the inner limiting membrane. Neovascular tufts and nonperfused areas were also reduced. Conclusions: High expression of netrin-1 was detected in the retina under ischemic conditions and played a significant role in pathological retinal angiogenesis. Therefore, netrin-1 represents a potential therapeutic target for diabetic retinopathy, retinopathy of prematurity and other ocular neovascular diseases. Copyright © 2011 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Purpose: To detect the expression of Netrin-1 in the retinas of diabetic rats and evaluate the relationship between Netrin-1 mRNA and diabetic retinopathy (DR)., Methods: Twenty healthy adult male Sprague-Dawley (SD) rats were randomly divided into a diabetic model group (DM) and a normal control group (NC), each group was composed of ten rats. Sreptozocin (STZ) was administered intraperitoneally at a single dose of 60 mg/kg to diabetic group. The control rats were injected only with citrate buffer. Collection of serum at 72 h after STZ treatment and measuring blood glucose levels confirmed the development of diabetes. The rats with blood glucose level 16.67 mmol/L or higher were considered to be diabetic and were used in the experiment. Retinal tissues were harvested and expression of netrin-1 mRNA and protein in the retina tissues was examined by reverse transcription polymerase chain reaction (RT-PCR) and western blot analysis, respectively., Results: Diabetic rats showed classic symptoms of diabetes mellitus, such as polydipsia, polyphagia, and polyuria. Cataract was seen in the DM group at 3 months after administration of STZ. Both netrin-1 mRNA and protein levels retina were dramatically increased in the DM rats compared to the NC group (P < 0.05)., Conclusion: Diabetic rats can be successfully established by intraperitoneal injection of streptozotocin (60 mg/kg). Netrin-1 may play an important role during the development of diabetic retinopathy.

Purpose: To investigate the significance of netrin-1 and vascular endothelial growth factor (VEGF) in the pathogenesis of retinal angiogenesis, the levels of netrin-1 and VEGF in the vitreous fluid and serum of the proliferative diabetic retinopathy (PDR) and non-proliferative diabetic retinopathy (non-PDR) patients were measured. We then determined the netrin-1 and VEGF expression in the oxygen induced retinopathy (OIR) mice retinas., Methods: A total of 18 eyes from 18 patients were included in our study and 10 of them were collected from PDR patients and 8 from non-PDR patients. Undiluted vitreous fluid samples were collected during pars plana vitrectomy. Appropriate blood samples were collected if possible. Netrin-1 and VEGF levels in the vitreous fluid and plasma were determined by Enzyme-linked Immunosorbent Assays. OIR mice models were established, and netrin-1 and VEGF levels were determined by immunohistochemistry analysis., Results: The levels of netrin-1 and VEGF in the vitreous of PDR patients were significantly higher than those in the controls (Mediannetrin-1=509.94 vs. 85.91 pg/ml, P<0.001 and Median VEGF=762.60 vs. 77.52 pg pg/ml, P<0.001). Netrin-1 was mainly expressed in GCL and INL of the retina in mice. Both netrin-1 and VEGF were up-regulated in OIR mice., Conclusion: Netrin-1 and VEGF levels were elevated in vitreous fluid of the PDR patients and the OIR mice retinas. Therefore, netrin-1 may play important roles in pathological retinal angiogenesis.