INVESTIGATION OF INCIDENCE AND CAUSES OF ACUTE VISION LOSS DURING ANTI-VASCULAR ENDOTHELIAL GROWTH FACTOR THERAPY FOR NEOVASCULAR AGE-RELATED MACULAR DEGENERATION DURING A FOUR-YEAR FOLLOW-UP.

PURPOSE: To investigate the incidence, risk factors, and outcomes of patients with age-related macular degeneration who experienced acute vision loss despite periodic injections of anti-vascular endothelial growth factor treatment for 4 years. METHODS: This retrospective cohort study included patients who were diagnosed with treatment-naive neovascular age-related macular degeneration and completed a 4-year follow-up. The incidence and risk factors for the occurrence of three or more lines of visual loss at every checkup were investigated. RESULTS: The analysis included 76 eyes of 76 patients. Acute vision loss occurred in 30 eyes (39.5%) over 4 years. Lower baseline best-corrected visual acuity and disrupted ellipsoid zone were independent predictors of vision loss occurrence. Although the causes and timing of visual acuity loss varied, retinal pigment epithelium tears were observed only in the first year. Most patients (86.7%) who experienced vision loss recovered their vision to pre-loss levels at least once; however, the final best-corrected visual acuity was worse than that in the group that did not experience acute vision loss. CONCLUSION: Approximately half of the patients with age-related macular degeneration experienced acute vision loss during a 4-year follow-up, despite continuous anti-vascular endothelial growth factor treatment. Most patients recovered from vision losses temporarily; however, they experienced worse visual outcomes subsequently.

Recurrence of neovascular age-related macular degeneration after cessation of treat and extend regimen.

The appropriate timing of treatment cessation after treat and extend (TAE) regimen for age-related macular degeneration has not been established. This study aimed to investigate the incidence and risk factors of recurrence after cessation of the TAE regimen. We included patients who received and discontinued the TAE regimen, after extension of the treatment interval to ≥ 12 weeks. Forty-nine patients were included in the study. The estimated recurrence rates were 33% at 1 year and 48% at 2 years after treatment cessation, respectively. Good visual acuity at cessation and a large number of injections in the 6 months before cessation were significant risk factors. Higher chances of recurrence were associated with < 0.1 logarithm of the minimum angle of resolution (logMAR) at cessation (P < 0.002). Meanwhile, five patients with visual acuity ≥ 1.0 logMAR at cessation did not show recurrence. Among the 25 recurrences, two lines of vision loss were noted in only two cases after resumed treatment. This study confirmed the importance of the number of injections in reducing recurrence and the association between visual acuity and recurrence. Recurrence is generally well-controlled with resumed treatment.

Understanding the Molecular Structure of the Sialic Acid-Phenylboronic Acid Complex by using a Combined NMR Spectroscopy and DFT Study: Toward Sialic Acid Detection at Cell Membranes.

The origin of the unusually high stability of the sialic acid (SA) and phenylboronic acid (PBA) complex was investigated by a combined nuclear magnetic resonance (NMR) spectroscopy and density functional theory (DFT) study. SA is a glycan-terminating monosaccharide, and its importance as a clinical target has long been recognized. Inspired by the fact that the binding properties of SA-PBA complexation are anomalously high relative to those of typical monosaccharides, great effort has been made to build a clinical platform with the use of PBA as a SA-selective receptor. Although a number of applications have been reported in recent years, the ability of PBA to recognize SA-terminating surface glycans selectively is still unclear, because high-affinity SA-PBA complexation might not occur in a physiological environment. In particular, different forms of SA (α- and ß-pyranose) were not considered in detail. To answer this question, the combined NMR spectroscopy/DFT study revealed that the advantageous binding properties of the SA-PBA complex arise from ester bonding involving the α-carboxylate moieties (C1 and C2) of ß-SA but not α-SA. Moreover, the facts that the C2 atom is blocked by a glycoside bond in a physiological environment and that α-SA basically exists on membrane-bound glycans in a physiological environment lead to the conclusion that PBA cannot selectively recognize the SA unit to discriminate specific types of cells. Our results have a significant impact on the field of SA-based cell recognition.

Wafer-scale fabrication and growth dynamics of suspended graphene nanoribbon arrays.

Adding a mechanical degree of freedom to the electrical and optical properties of atomically thin materials can provide an excellent platform to investigate various optoelectrical physics and devices with mechanical motion interaction. The large scale fabrication of such atomically thin materials with suspended structures remains a challenge. Here we demonstrate the wafer-scale bottom-up synthesis of suspended graphene nanoribbon arrays (over 1,000,000 graphene nanoribbons in 2 × 2 cm(2) substrate) with a very high yield (over 98%). Polarized Raman measurements reveal graphene nanoribbons in the array can have relatively uniform-edge structures with near zigzag orientation dominant. A promising growth model of suspended graphene nanoribbons is also established through a comprehensive study that combined experiments, molecular dynamics simulations and theoretical calculations with a phase-diagram analysis. We believe that our results can contribute to pushing the study of graphene nanoribbons into a new stage related to the optoelectrical physics and industrial applications.

Optimized Culture System to Induce Neurite Outgrowth From Retinal Ganglion Cells in Three-Dimensional Retinal Aggregates Differentiated From Mouse and Human Embryonic Stem Cells.

PURPOSE: To establish a practical research tool for studying the pathogenesis of retinal ganglion cell (RGC) diseases, we optimized culture procedures to induce neurite outgrowth from three-dimensional self-organizing optic vesicles (3D-retinas) differentiated in vitro from mouse and human embryonic stem cells (ESCs). MATERIALS AND METHODS: The developing 3D-retinas isolated at various time points were placed on Matrigel-coated plates and cultured in media on the basis of the 3D-retinal culture or the retinal organotypic culture protocol. The number, length, and morphology of the neurites in each culture condition were compared. RESULTS: First, we confirmed that Venus-positive cells were double-labeled with a RGC marker, Brn3a, in the 3D-retina differentiated from Fstl4::Venus mouse ESCs, indicating specific RGC-subtype differentiation. Second, Venus-positive neurites grown from these RGC subsets were positive for beta-III tubulin and SMI312 by immunohistochemistry. Enhanced neurite outgrowth was observed in the B27-supplemented Neurobasal-A medium on Matrigel-coated plates from the optic vesicles isolated after 14 days of differentiation from mouse ESCs. For the differentiated RGCs from human ESCs, we obtained neurite extension of >4 mm by modifying Matrigel coating and the culture medium from the mouse RGC culture. CONCLUSION: We successfully optimized the culture conditions to enhance lengthy and high-frequency neurite outgrowth in mouse and human models. The procedure would be useful for not only developmental studies of RGCs, including maintenance and projection, but also clinical, pathological, and pharmacological studies of human RGC diseases.

Cyclic stretch and hypertension increase retinal succinate: potential mechanisms for exacerbation of ocular neovascularization by mechanical stress.

PURPOSE: We investigated succinate metabolism in cells undergoing clinically relevant cyclic stretch and in spontaneously hypertensive rat (SHR) retina. METHODS: We seeded ARPE-19 cells on 6-well BioFlex collagen I-coated, silicone elastomer-bottomed culture plates. Cells then were subjected to pulsatile stretch using a computer-controlled vacuum stretch apparatus. A physiologic stretch frequency of 60 cycles per minute and 5% to 15% prolongation of the elastomer-bottomed plates were used. Succinate concentration was assessed by enzymatic analysis and high-performance liquid chromatography-mass spectrometry. The VEGF was measured using enzyme-linked immunosorbent assays. The 12-week-old male SHRs and weight-matched Wistar-Kyoto (WKY) control rats were treated with or without 100 mg·kg(-1)·day(-1) captopril for 1 week. The vitreous body and retina of each rat were extracted after 1 week of therapy, and the vitreoretinal succinate concentration was measured. RESULTS: Cells exposed to cyclic stretch accumulated intracellular succinate in a time- and magnitude-dependent manner, and also accumulated VEGF protein levels. Moreover, BAPTA/AM, an intracellular calcium chelate reagent, significantly inhibited the stretch-induced succinate increase. After cyclic stretch, levels of intracellular fumarate, a citric acid cycle intermediate, also were significantly increased compared to controls. The BAPTA/AM inhibited this increase. For the in vivo experiments, hypertension increased vitreoretinal succinate and fumarate in SHRs compared to the normotensive WKY controls. When hypertension was reduced using captopril, vitreoretinal succinate returned to baseline levels. CONCLUSIONS: These findings suggest that cyclic stretch and hypertension increased intracellular succinate in cultured retinal pigment epithelial cells and the vitreoretinal succinate of SHRs through a calcium-dependent pathway.

Enhanced depth imaging optical coherence tomography of the choroid in central retinal vein occlusion.

PURPOSE: To evaluate subfoveal choroidal thickness in patients with central retinal vein occlusion (CRVO) using enhanced depth imaging optical coherence tomography. DESIGN: Retrospective observational study. METHODS: We measured bilateral subfoveal choroidal thickness, averaged for 100 scans, in 36 patients (mean age, 66 ± 15 years; 26 women and 10 men) with unilateral CRVO by using the enhanced depth imaging methods of the Spectralis optical coherence tomography system. Twenty-two patients were treated with intravitreal bevacizumab (1.25 mg/0.05 mL), and subfoveal choroidal thickness was measured before and after treatment. Statistical analysis was performed to compare subfoveal choroidal thickness of CRVO and fellow eyes and to compare subfoveal choroidal thickness before and after intravitreal bevacizumab. RESULTS: Mean subfoveal choroidal thickness measured in 36 eligible eyes of 36 patients was 257.1 ± 83.2 µm, which was significantly greater than that in fellow eyes (222.6 ± 67.8 µm; P < .01, paired t test). There was strong correlation between CRVO eyes and fellow eyes (r = 0.79, P < .01). Mean subfoveal choroidal thickness after intravitreal bevacizumab was 227.7 ± 65.1 µm, which was significantly thinner than that before intravitreal bevacizumab therapy (266.9 ± 79.0 µm; P < .01, paired t test). CONCLUSIONS: Subfoveal choroidal thickness of CRVO eyes was significantly greater than that of fellow eyes and decreased significantly after intravitreal bevacizumab treatment. Enhanced depth imaging optical coherence tomography can be used to evaluate choroidal involvement in CRVO and may assist noninvasive diagnosis and management of this disease.

Protective effects of the fermented milk Kefir on X-ray irradiation-induced intestinal damage in B6C3F1 mice.

Gastrointestinal damage associated with radiation therapy is currently an inevitable outcome. The protective effect of Kefir was assessed for its usefulness against radiation-induced gastrointestinal damage. A Kefir supernatant was diluted by 2- or 10-fold and administered for 1 week prior to 8 Gray (Gy) X-ray irradiation at a dose rate of 2 Gy/min, with an additional 15 d of administration post-irradiation. The survival rate of control mice with normal drinking water dropped to 70% on days 4 through 9 post-irradiation. On the other hand, 100% of mice in the 10- and 2-fold-diluted Kefir groups survived up to day 9 post-irradiation (p<0.05 and p<0.01, respectively). Examinations for crypt regeneration against 8, 10 and 12 Gy irradiation at a dose rate of 4 Gy/min revealed that the crypt number was significantly increased in the mice administered both diluted Kefir solutions (p<0.01 for each). Histological and immunohistochemical examinations revealed that the diluted Kefir solutions protected the crypts from radiation, and promoted crypt regeneration. In addition, lyophilized Kefir powder was found to significantly recover the testis weights (p<0.05), but had no effects on the body and spleen weights, after 8 Gy irradiation. These findings suggest that Kefir could be a promising candidate as a radiation-protective agent.