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German V. Fuentes Eric N. Doucet Alyson Abraham Nikki K. Rodgers Felix Alonso Nelson Euceda Michael H. Quinones Penelope A. Riascos Kristelle Pierre Nuhash H. Sarker Manya Dhar-Mascareno Mircea Cotlet Kim Kisslinger Fernando Camino Mingxing Li Fang Lu Ruomei Gao 《RSC advances》2020,10(29):17094
It is both challenging and desirable to have drug sensitizers released at acidic tumor pH for photodynamic therapy in cancer treatment. A pH-responsive carrier was prepared, in which fumed silica-attached 5,10,15,20-tetrakis(4-trimethylammoniophenyl)porphyrin (TTMAPP) was encapsulated into 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) nanocomposite liposomes. The sizes of agglomerates were determined by dynamic light scattering to be 115 nm for silica and 295 nm for silica-TTMAPP-DOPC liposomes. Morphological changes were also found in TEM images, showing liposome formation at pH 8.5 but collapse upon silanol protonation. TTMAPP release is enhanced from 13% at pH 7.5 to 80% at pH 2.3, as determined spectrophotometrically through dialysis membranes. Fluorescence emission of TTMAPP encapsulated in the dry film of liposomes was reduced to half at pH 8.6 when compared to that at pH 5.4, while the production of singlet oxygen was quintupled at pH 5.0 compared to pH 7.6. Upon treatment of human prostate cancer cells with liposomes containing 6.7 μM, 13 μM, 17 μM and 20 μM TTMAPP, the cell viabilities were determined to be 60%, 18%, 20% and 5% at pH 5.4; 58%, 30%, 25% and 10% at pH 6.3; and 90%, 82%, 68% and 35% at pH 7.4, respectively. Light-induced apoptosis in cancerous cells was only observed in the presence of liposomes at pH 6.3 and pH 5.4 but not at pH 7.4, as indicated by chromatin condensation.Nanocomposite liposomes are relatively stable in weak basic solutions but effectively release porphyrins at acidic pH, as indicated by the difference in fluorescence. 相似文献
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Kropf P Baud D Marshall SE Munder M Mosley A Fuentes JM Bangham CR Taylor GP Herath S Choi BS Soler G Teoh T Modolell M Müller I 《European journal of immunology》2007,37(4):935-945
Complex regulation of T cell functions during pregnancy is required to ensure materno-fetal tolerance. Here we reveal a novel pathway for the temporary suppression of maternal T cell responses in uncomplicated human pregnancies. Our results show that arginase activity is significantly increased in the peripheral blood of pregnant women and remarkably high arginase activities are expressed in term placentae. High enzymatic activity results in high turnover of its substrate L-arginine and concomitant reduction of this amino acid in the microenvironment. Amino acid deprivation is emerging as a regulatory pathway of lymphocyte responses and we assessed the consequences of this enhanced arginase activity on T cell responses. Arginase-mediated L-arginine depletion induces down-regulation of CD3 zeta, the main signalling chain of the TCR, and functional T cell hyporesponsiveness. Importantly, this arginase-mediated T cell suppression was reversible, as inhibition of arginase activity or addition of exogenous L-arginine restored CD3 zeta chain expression and T cell proliferation. Thus, L-arginine metabolism constitutes a novel physiological mechanism contributing to the temporary suppression of the maternal immune response during human pregnancy. 相似文献
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Farah Kaissar Leroy Henri-Arthur Karnoub Melodie-Anne Obled Louis Fuentes Stephane Assaker Richard 《European spine journal》2020,29(2):306-313
European Spine Journal - To evaluate whether left hip positioning widened the access corridor using oblique lateral interbody fusion (OLIF) approach during right lateral decubitus (RLD). Ten... 相似文献