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In this work, 31.4 wt.% Ni/SBA-15 (Ni/SBA-15) nonpromoted and alkalized with ammonia solution and by MgO promoter catalysts were prepared and used for combined steam and CO2 reforming of CH4 (bireforming). Effect of concentration of ammonia solution (NH3(aq)) (10–25 vol.%) and Mg content (3–12 wt.%) on the properties of the Ni/SBA-15 catalysts was investigated by low-angle and powder X-ray diffraction (XRD), N2-BET isothermal adsorption, SEM, TEM, EDS mapping, H2-TPR, and CO2-TPD methods. The performance of the catalysts in bireforming was assessed in the temperature range of 550–800°C. The enhancement of dispersion of NiO particles, reducibility, and basicity of alkalized Ni/SBA-15 catalysts were responsible for improving the catalytic performance of this catalyst. The results revealed that the Ni/SBA-15 treated with 15-25% NH3(aq) solution and promoted with 3-9% Mg exhibited high activity for CH4 conversion. Meanwhile, Ni6Mg/SBA-15 showed the highest CO2 conversion. Among tested catalysts, Ni/SBA-15-20NH3 and Ni9Mg/SBA-15 samples had an almost equal activity with a CH4 conversion of nearly 97% and a CO2 conversion of about 84% at 700°C thanks to its moderate affinity with both CO2 and CH4. However, the H2/CO ratio of the product mixture remained at 2.02 on the Ni/SBA-15-20NH3 catalyst and almost 1 on the Ni9Mg/SBA-15 sample. These results might be related to the fact that the alkalization of the Ni/SBA-15 catalyst by NH3(aq) solution had an advantage over using MgO because side reactions were unlikely to occur. [ABSTRACT FROM AUTHOR]

AimsTo determine the correlation between systemic corticosteroid therapy and the occurrence and size of peripapillary atrophy (PPA) in patients with Vogt–Koyanagi–Harada (VKH) disease.MethodsAll patients with VKH disease were retrospectively reviewed for their corticosteroid regimen. The extent of the PPA, if present, was measured using digitized imaging software, by two masked observers. Eyes with myopia greater than 6 dioptres or glaucoma were excluded. The patients were classified into three groups: early high (EH), late high (LH), and low dose (LD), according to the dose and timing of corticosteroids received during the acute phase of the disease.ResultsThere were 40 eyes in the EH group, 25 eyes in the LH group, and 23 eyes in the LD group. Multivariate analysis showed that corticosteroid therapy was the main determinant of PPA occurrence. All the eyes in the LD group had PPA and eyes in the LH groups were 4.02 times (95% confidence interval 1.24–13.07) more likely to develop PPA than those in the EH group. The LD group also had larger PPA to disc ratios than the EH group. (Mean of 2.83 vs0.19, P<0.001)ConclusionThe development and extent of PPA in patients with VKH disease appear to be dependent on the dose and timing of systemic corticosteroids.Eye (2008) 22, 240–245; doi:10.1038/sj.eye.6702591; published online 15 September 2006 [ABSTRACT FROM AUTHOR]

Aim: To assess retinal function by multifocal electroretinogram (mfERG) in children on atropine eye drops for the treatment of myopia. Methods: mfERGs were recorded in children receiving atropine eye drops (n = 48) once daily for 2 years and in those receiving placebo eye drops (n = 57) for a similar times. All recordings were performed between the second and third month of cessation of atropine/placebo treatment by a masked investigator. The amplitude and implicit time of the first order kernel (k1) and first slice of the second order kernel (k21) of mfERG responses were used to study the outer and inner retinal function, respectively. Results: There was no significant reduction in k1 response amplitudes of the atropine group compared to that of the placebo group (N1, p = 0.181; P1, p = 0.150). No significant difference in the k1 response implicit times between the groups was found (N1, p = 0.767; P1, p = 0.849). The differences in the k21 amplitudes an implicit times between the groups were not statistically significant (k21 amplitude, p = 0.058; k21 implicit time, p = 0.156). Conclusions: Daily atropine usage over 2 years for the treatment of myopia has no significant effect on retinal function as demonstrated by recordings of mfERG. [ABSTRACT FROM AUTHOR]

PurposeTo investigate the possible roles of retinal photoreceptors in macular oedema and retinal angiogenesis with particular reference to the mode of action of laser therapy.Methods(i) Studies in rats made hypoxic for 2 h by administering an oxygen/nitrogen mixture of reduced oxygen content, and growth factors determined by RT-PCR, western blotting, and immunohistochemistry. Assessment of blood–retinal barrier integrity using fluorescent and electron-dense tracers. (ii) Studies in pigs with one retina made hypoxic by selective embolisation of the retinal capillary circulation with fluorescent microspheres. (iii) Assessment of laser therapy in selected cases of retinal neovascularisation indicating a role for photoreceptors.ResultsIn the hypoxic retina, angiogenic and vascular permeability factors such as vascular endothelial growth factor (VEGF), nitric oxide synthases (NOSs), and insulin-like growth factor-1 are upregulated in retinal astrocytes and Müller cells but are also present in large amount in the photoreceptors. Hypoxia-inducible factor-1 (HIF-1) is upregulated in retinal glial cells but not in the photoreceptors, suggesting that growth factors in the photoreceptors may not have been generated there. The tracer dye, rhodium isothiocyanate, leaking from an abnormally permeable inner blood–retinal barrier in the hypoxic retina accumulates in the photoreceptors.ConclusionsThe results indicate that laser treatment of macular oedema or retinal neovascularisation may obtain its effect not only by improving oxygen availability in the inner retina, but also by reducing the load of angiogenic/permeability factors that accumulate in the photoreceptors in hypoxic/ischaemic conditions. [ABSTRACT FROM AUTHOR]

Age-related macular degeneration (AMD) is a leading cause of vision loss, characterized by drusen deposits and thickened Bruch's membrane (BM). This study details the capacity of nanosecond laser treatment to reduce drusen and thin BM while maintaining retinal structure. Fifty patients with AMD had a single nanosecond laser treatment session and after 2 yr, change in drusen area was compared with an untreated cohort of patients. The retinal effect of the laser was determined in human and mouse eyes using immunohistochemistry and compared with untreated eyes. In a mouse with thickened BM (ApoEnull), the effect of laser treatment was quantified using electron microscopy and quantitative PCR. In patients with AMD, nanosecond laser treatment reduced drusen load at 2 yr. Retinal structure was not compromised in human and mouse retina after laser treatment, with only a discrete retinal pigment epithelium (RPE) injury, and limited mononuclear cell response observed. BM was thinned in the ApoEnull mouse 3 mo after treatment (ApoEnull treated 683 ± 38 nm, ApoEnull untreated 890 ± 60 nm, C57Bl6J 606 ± 43 nm), with the expression of matrix metalloproteinase-2 and -3 increased (>260%). Nanosecond laser resolved drusen independent of retinal damage and improved BM structure, suggesting this treatment has the potential to reduce AMD progression. [ABSTRACT FROM AUTHOR]

We report on the long-term safety of AAV2.sFlt-1 (a recombinant adeno-associated virus serotype 2 carrying the soluble form of the Flt-1 receptor) injection into the subretinal space of non-human primates. Levels of sFlt-1 protein were significantly higher (P<0.05) in the vitreous of four out of five AAV2.sFlt-1-injected eyes. There was no evidence of damage to the eyes of animals that received subretinal injections of AAV2.sFlt-1; ocular examination showed no anterior chamber flare, normal fundus and electroretinography responses equivalent to those observed before treatment. Notably, immunological analysis demonstrated that gene therapy involving subretinal injection of AAV2.sFlt-1 does not elicit cell-mediated immunity. Biodistribution analysis showed that AAV2.sFlt-1 could be detected only in the eye and not in the other organs tested. These data indicate that gene therapy with subretinal AAV2.sFlt-1 is safe and well tolerated, and therefore promising for the long-term treatment of neovascular diseases of the eye. [ABSTRACT FROM AUTHOR]

Background: The search for a reliable biological marker in depression is on-going. Visual contrast sensitivity has recently been reported to be lower in depressed patients compared to healthy controls. We aim to examine the consistency of this finding and to explore the underlying retinal electrophysiology. Methods: Pattern electroretinogram and subjective visual contrast test were used to assess visual contrast sensitivity in 20 subjects with major depressive disorder and 20 healthy controls. Full-field electroretinography assessed the general neurophysiology of retinal function. Depression was diagnosed based on DSM-IV criteria and depression severity was measured by MADRS and BDI. Results: Visual contrast sensitivity was significantly lower in depresssed patients than controls based on Landolt C visual contrast test [Weber 2.25±1.84(SD) vs. 1.20±0.64(SD); p=0.02]. No difference was found between the groups using PERG. Greater severity of depressive symptoms correlated with poorer visual contrast sensitivity (r=0.49, p=0.001). Conclusion: Although depressed subjects clearly had reduced visual contrast sensitivity, this was not consistently demonstrated using PERG. The neurobiological link between major depressive disorder and visual contrast sensitivity requires further investigation. [ABSTRACT FROM AUTHOR]