Anticipation,anti-glaucoma drug treatment response and phenotype of a Chinese family with glaucoma caused by the Pro370Leu myocilin mutation

AIM: To describe the anticipation and anti-glaucoma drugs response of a Chinese family with juvenile-onset open angle glaucoma(JOAG) caused by the Pro370Leu myocilin(MYOC) mutation. ·METHODS: Fifteen members of a three-generation Chinese family with JOAG were recruited to this study. They all underwent ophthalmic common examinations. Patients suspected to have JOAG got an assessment of visual field and optical coherence tomography. Intraocular pressures(IOPs) of four patients were measured at 8,10,12,14,17 o’clock respectively after using anti-glaucoma drugs. Mutation screening of all MYOC gene coding exons of the participants was performed by using direct sequencing of PCR products. ·RESULTS: Clinical examinations and pedigree analysis revealed eight family members were suffered from JOAG. Apparent genetics anticipation phenomenon was observed in this family. Their clinical features included elevated IOP of 35-55mmHg,loss of visual field,thinning of retinal nerve fiber layer,and glaucomatous optic disc damage. Noticeably,their intraocular pressure levels could be controlled within normal range at 8 and 10 o’clock by anti-glaucoma drugs,but their IOPs would elevate 】21mmHg after 12 o’clock. Seven patients received trabeculectomy produced thin-walled,pale,and saccate filtering blebs maintaining lower intraocular pressure efficiently. Mutation screening indentified aheterozygous C→T missense mutation in the MYOC gene at position 1 109 in exon 3,corresponding to a substitution of a highly conserved proline to leucine at codon 370 in the olfactomedin domain of MYOC. ·CONCLUSION: The clinical characteristics of JOAG in this family were 1) genetics anticipation; 2) high IOP; 3) temporay response to anti-glaucoma drugs; 4) filtering surgery produced thin-walled and saccate filtering blebs,helping maintain lower IOP.

Mitochondrial expression and activity of P-glycoprotein under oxidative stress in outer blood-retinal barrier

AIM： To investigate the role of oxidative stress in regulating the functional expression of P-glycoprotein（P-gp） in mitochondria of D407 cells.METHODS： D407 cells were exposed to different ranges of concentrations of H2O2. The mitochondrial location of P-gp in the cells subjected to oxidative stress was detected by confocal analysis. Expression of P-gp in isolated mitochondria was assessed by Western blot. The pump activity of P-gp was evaluated by performing the efflux study on isolated mitochondria with Rhodamine 123（Rho-123） alone and in the presence of P-gp inhibitor（Tariquidar） using flow cytometry analysis. The cells were pretreated with 10 mmol/L N-acetylcysteine（NAC） for 30 min before exposing to H2O2, and analyzed the mitochondrial extracts by Western blot and flow cytometry.RESULTS： P-gp was co-localized in the mitochondria by confocal laser scanning microscopy, and it was also detected in the mitochondria of D407 cells using Western blot. Exposure to increasing concentrations of H2O2 led to gradually increased expression and location of P-gp in the mitochondria of cells. Rho-123 efflux assay showed higher uptake of Rho-123 on isolated mitochondria in the presence of Tariquidar both in normal and oxidative stress state. H2O2 up-regulated P-gp in D407 cells, which could be reversed by NAC treatment. CONCLUSION： H2O2 could up-regulate the functional expression of P-gp in mitochondria of D407 cells, while antioxidants might suppress oxidative-stress-induced over-expression of functional P-gp. It is indicative that limiting the mitochondrial P-gp transport in retinal pigment epithelium cells would be to improve the effect of mitochondria-targeted antioxidant therapy in age-related macular degeneration-like retinopathy.

Asymptotic Property of Approximation to x~αsgn x by Newman Type Operators

Approximation to the function ｜x｜ plays an important role in approximation theory. This paper studies the approximation to the function xαsgn x, which equals ｜x｜ if α = 1. We construct a Newman Type Operator rn（x） and prove max ｜x｜≤1｜xαsgn x-rn（x）｜～Cn1/4e-π1/2（1/2）αn.