Excited-State Charge Transfer in Push-Pull Platinum(II) π-Extended Porphyrins Fused with Pentacenequinone.

Platinum(II) π-extended porphyrins fused with pentacenequinone and dihydropentacene have been successfully synthesized. These porphyrins were investigated using various techniques including absorption, steady-state, and time-resolved phosphorescence spectroscopy and differential pulse voltammetry. UV-vis absorption spectra of pentacenequinone-fused porphyrins (SW-Pt1 and SW-Pt2) showed unusually broad and nontypical absorption patterns. Phosphorescence spectra of SW-Pt1, SW-Pt2, and SW-Pt3 displayed similar emissions in the 704-706 nm region indicating electronic transitions of similar origin; however, the triplet lifetimes were found to be quenched in the case of both SW-Pt1 and SW-Pt2, suggesting the occurrence of excited-state events. Facile reductions were obtained for both the pentacene-quinone-fused monomer (SW-Pt2) and dimer (SW-Pt1) and were identified to be located at the pentacenequinone components. The observed orbital segregations for SW-Pt2 and SW-Pt1 from DFT calculations supported the possibility of charge transfer in these push-pull systems. Interestingly, the established energy level diagram revealed that the charge transfer from the triplet excited Pt porphyrin is thermodynamically an uphill process. Systematic studies involving both femtosecond and nanosecond transient absorption techniques revealed that the singlet excited Pt porphyrins undergo an intermediate charge transfer state prior to populating the triplet state, providing a plausible explanation for phosphorescence quenching. The lifetime of the intermediate charge transfer states was found to be 25.9 and 5.68 ps, respectively, for SW-Pt1 and SW-Pt2.

Spread-out Bragg peak measurements using a compact quality assurance range calorimeter at the Clatterbridge cancer centre.

Objective.The superior dose conformity provided by proton therapy relative to conventional x-ray radiotherapy necessitates more rigorous quality assurance (QA) procedures to ensure optimal patient safety. Practically however, time-constraints prevent comprehensive measurements to be made of the proton range in water: a key parameter in ensuring accurate treatment delivery.Approach.A novel scintillator-based device for fast, accurate water-equivalent proton range QA measurements for ocular proton therapy is presented. Experiments were conducted using a compact detector prototype, the quality assurance range calorimeter (QuARC), at the Clatterbridge cancer centre (CCC) in Wirral, UK for the measurement of pristine and spread-out Bragg peaks (SOBPs). The QuARC uses a series of 14 optically-isolated 100 × 100 × 2.85 mm polystyrene scintillator sheets, read out by a series of photodiodes. The detector system is housed in a custom 3D-printed enclosure mounted directly to the nozzle and a numerical model was used to fit measured depth-light curves and correct for scintillator light quenching.Main results.Measurements of the pristine 60 MeV proton Bragg curve found the QuARC able to measure proton ranges accurate to 0.2 mm and reduced QA measurement times from several minutes down to a few seconds. A new framework of the quenching model was deployed to successfully fit depth-light curves of SOBPs with similar range accuracy.Significance.The speed, range accuracy and simplicity of the QuARC make the device a promising candidate for ocular proton range QA. Further work to investigate the performance of SOBP fitting at higher energies/greater depths is warranted.

Ameliorating hydroxychloroquine induced retinal toxicity through cerium oxide nanoparticle treatments.

The present study investigated the potential protective effects of cerium oxide nanoparticles (CNP) on human retinal pigment epithelium (ARPE-19) cells damaged by hydroxychloroquine (HCQ). Toxicity of HCQ on the ARPE-19 cells was explored with a dose response trial. CNP rescue both a pre-treatment protocol, where CNP were applied 24 hours prior to HCQ application and a simultaneous treatment protocol where both CNP and HCQ were applied together, were used. In the dose response trial, 250 µM HCQ showed 51.84% cell viability after 24 hours and 32.75% after 48 hours time period. This was selected as model HCQ dose for rescue trials. The simultaneous treatment trials did not show a significant increase in viability compared to model toxic dose. The CNP pre-treatment trials showed a significant increase in cellular viability compared to model toxic dose with 68.03% ± 3.27 viability (p = 4.56E-05) at 24 hours and 51.85% ± 4.96 (p = 1.18E-05) at 48 hours time period. CNP pre-treatment showed significant protection of cells from HCQ induced toxicity. The difference in efficacy of simultaneous and pre-treatment is hypothesized to lie in the cellular localization of CNP. Furthermore, including the reactive oxygen species (ROS) scavenging properties of CNP seems to be responsible for protection, the effect of CNP on autophagosome and lysosome colocalization are also hypothesized to play a significant role.

Incidence of endophthalmitis after 20-gauge vs 23-gauge vs 25-gauge pars plana vitrectomy.

PURPOSE: To compare endophthalmitis rates after 20-gauge versus 23-gauge versus 25-gauge pars plana vitrectomy (PPV) in 2007-2008, and compare the rates with those of 2005-2006. METHODS: Multicenter study including all patients who developed endophthalmitis following PPV performed by any of the authors during 2005-2008, and all patients who developed endophthalmitis following PPV at Penn State College of Medicine and Bascom Palmer Eye Institute during 2005-2008. The endophthalmitis rates after 20-gauge, 23-gauge and 25-gauge PPV during 2007-2008 were compared to those from 2005-2006. RESULTS: The endophthalmitis incidence during 2007-2008 was 1/4,403 (0.02%) for 20-gauge PPV, 1/3,362 (0.03%) for 23-gauge PPV, and 1/789 (0.13%) for 25-gauge PPV. There is no significant difference among these rates between any two of the three groups. Compared with the endophthalmitis rates among the same group of surgeons during 2005-2006, the 2007-2008 endophthalmitis rates following 20-gauge and 23-gauge PPV were stable, and the rate following 25-gauge PPV was marginally lower (p = 0.056; odds ratio = 0.15; 95% CI: (0.003, 1.03)). CONCLUSIONS: There was no significant difference in the 2007-2008 rates of endophthalmitis following 20-gauge versus 23-gauge versus 25-gauge PPV; among the same group of surgeons, the 2007-2008 rate of endophthalmitis following 25-gauge PPV was marginally lower than the 2005-2006 rate.

Multiple Evanescent White Dot Syndrome Presenting After Initiation of Empagliflozin, a Sodium-Glucose Cotransporter-2 Inhibitor.

Multiple evanescent white dot syndrome (MEWDS) is an inflammatory condition of the retina that typically presents unilaterally with multiple gray-white spots in the outer retina or retinal pigmented epithelium and granular changes within the fovea. We report a case of new-onset MEWDS in a patient closely after the initiation of empagliflozin, a sodium-glucose cotransporter inhibitor medicine for his type II diabetes mellitus.

Late Intraocular Lens Dislocation Resulting From Haptic Breakage Following Cardiopulmonary Resuscitation.

We report a case of an asymptomatic 65-year-old male who on routine eye examination had anterior dislocation of an intraocular lens (IOL) implant placed 23 years prior. Ten months prior to presentation, the patient had cardiac surgery complicated by cardiac arrest requiring chest compressions. Dislocation of an intraocular lens is a rare complication of cataract surgery. One of the causative factors for haptic breakage in our case was the polyimide haptic material. Polyimide has been shown to become brittle over time in warm and moist environments such as the human eye. This case demonstrates a case of late IOL dislocation chest compressions and, to the best of our knowledge, the first such case reported in the literature.

Ceria Nanoparticles Mitigate the Iron Oxidative Toxicity of Human Retinal Pigment Epithelium.

Oxidative injury is implicated in retinal damage observed in age-related macular degeneration (AMD), as well as other degenerative conditions. Abnormally elevated levels of iron accumulation within the retinal pigment epithelium have been detected in eyes with AMD, and it is suspected to play a role in the pathogenesis through the production of reactive oxygen species (ROS). Ceria nanoparticles (CNP) have the ability to scavenge ROS. This study sought to evaluate the ability of CNP to mitigate iron-induced oxidative stress and assess cell viability in the human ARPE-19 cell line in vitro. Cell viability was measured by an MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and compared between experimental groups undergoing 48-hr exposure to a ferrous iron solution with and without 24-hr CNP pre-treatment. The CNP effect on ROS formation was evaluated additionally by H2DCFDA (2,7-dichlorodihydrofluorescein diacetate) fluorescent probe assay and superoxide dismutase assay. CNP demonstrated a three-fold increase in cell viability and a reduction in ROS generation. The results show a promising treatment modality for diseases causing oxidative damage in the eye.

Optical Coherence Tomography Angiography Findings in a Case of Cosmetic Laser Induced Retinal Injury.

We report the first known case of iris and retinal injury using optical coherence tomography angiography (OCTA) images following cosmetic laser injury. A 23-year-old female developed left iris and retinal injury post inadvertent firing of a 755 nm Alexandrite cosmetic laser. The patient had no significant past medical history and the injury resulted from inappropriate eye protection during laser use. Injury from the laser caused damage to the retinal pigment epithelium (RPE), iris pigment epithelium (IPE), and ciliary body epithelium (CPE). The OCTA imaging modality detected the vascular injury caused by the Alexandrite 755 nm laser to the choroid and RPE with subsequent images visualizing the healing response in the months postinjury.

Bilateral Superior Altitudinal Hemianopsia with Macular Involvement Confirmed by Multifocal Visual Evoked Potential Testing.

We report a case of bilateral superior altitudinal hemianopsia (BSAH) secondary to pituitary microadenoma related inferior optic chiasm damage. A 69-year-old-female developed a BSAH with macular involvement that was initially considered as malingering due to the obscurity of this symptom. The patient presents with multiple risk factors for ischemic disease to the ocular and occipital vessels, persistent migraine, hypothyroidism, and a stable pituitary microadenoma, yet no evidence of tissue ischemia or infarction was noted on imaging that could account for her visual field defects. A prior history of pituitary microadenoma is presumed to be the etiologic cause although the lesion had regressed by the time of presentation.

RETOUCH: The Retinal OCT Fluid Detection and Segmentation Benchmark and Challenge.

Retinal swelling due to the accumulation of fluid is associated with the most vision-threatening retinal diseases. Optical coherence tomography (OCT) is the current standard of care in assessing the presence and quantity of retinal fluid and image-guided treatment management. Deep learning methods have made their impact across medical imaging, and many retinal OCT analysis methods have been proposed. However, it is currently not clear how successful they are in interpreting the retinal fluid on OCT, which is due to the lack of standardized benchmarks. To address this, we organized a challenge RETOUCH in conjunction with MICCAI 2017, with eight teams participating. The challenge consisted of two tasks: fluid detection and fluid segmentation. It featured for the first time: all three retinal fluid types, with annotated images provided by two clinical centers, which were acquired with the three most common OCT device vendors from patients with two different retinal diseases. The analysis revealed that in the detection task, the performance on the automated fluid detection was within the inter-grader variability. However, in the segmentation task, fusing the automated methods produced segmentations that were superior to all individual methods, indicating the need for further improvements in the segmentation performance.

Micro-computed tomography prediction of biomechanical strength in murine structural bone grafts.

Correlating massive bone graft strength to parameters derived from non-invasive imaging is important for pre-clinical and clinical evaluation of therapeutic adjuvants designed to improve graft repair. Towards that end, univariate and multivariate regression between measures of graft and callus geometry from micro-CT imaging and torsional strength and rigidity were investigated in a mouse femoral graft model. Four millimeter mid-diaphyseal defects were grafted with live autografts or processed allografts and allowed to heal for 6, 9, 12, or 18 weeks. We observed that allograft remodeling and incorporation into the host remained severely impaired compared to autografts mainly due to the extent of callus formation around the graft, the rate and extent of the graft resorption, and the degree of union between the graft and host bone as judged by post-mechanical testing analysis of the mode of failure. The autografts displayed greater ultimate torque and torsional rigidity compared to the allografts over time. However the biomechanical properties of allografts were equivalent to autografts by 9 weeks but significantly decreased at 12 and 18 weeks. Multivariate regression analysis demonstrated significant statistical correlations between combinations of the micro-CT parameters (graft and callus volume and cross-sectional polar moment of inertia) with the measured ultimate torque and torsional rigidity (adjusted R(2)=44% and 50%, respectively). The statistical correlations approach used in this mouse study could be useful in guiding future development of non-invasive predictors of the biomechanical properties of allografts using clinical CT.

Retinal pigment epithelial tears after intravitreal bevacizumab injection for exudative age-related macular degeneration.

We report a series of retinal pigment epithelial (RPE) tears after intravitreal bevacizumab therapy for choroidal neovascularization associated with age-related macular degeneration (ARMD). Retinal pigment epithelial tears were estimated to occur at an incidence of 1.6% in this patient population at our institution. Ophthalmologists should be aware of this rare but serious finding associated with exudative macular degeneration therapy.

Retinitis Pigmentosa Associated with Glucose-6-Phosphate Dehydrogenase Deficiency.

We report a case of new onset retinitis pigmentosa (RP) associated with a glucose-6-phosphate dehydrogenase (G6PD) deficiency in a 63-year-old African-American male who presented with worsening night vision over a period of five years. The pathogenesis of G6PD-mediated oxidative biological damage is reviewed and a mechanism for the onset of retinal disease proposed.

Bilateral Retinal Detachments Associated with Inversion Table Therapy.

To report a case of sequential bilateral inferior retinal detachments secondary to inversion table therapy. A 67-year-old-male developed inferior rhegmatoegnous retinal detachments (RRD) in both eyes on two different occasions with the use of inversion therapeutic tables. Various predisposing factors have been documented for RRD such as previous cataract surgery, peripheral retinal degenerations, high myopia, history of previous retinal detachments and direct ocular trauma. The authors report here a case of inferior retinal detachments associated with the use of inversion therapy. Physical therapists, physical medicine rehabilitation physicians, and retinal specialists need be aware of this potential complication.

Combined DSEK and Transconjunctival Pars Plana Vitrectomy.

We report here three patients who underwent combined Descemet's stripping with endothelial keratoplasty and transconjunctival pars plana vitrectomy for bullous keratopathy and posterior segment pathology. A surgical technique and case histories are described. Anatomic and visual outcomes of combined Descemet's stripping with endothelial keratoplasty and vitrectomy were excellent. Our experience provides technical guidelines and limitations. The combined minimally invasive techniques allow for rapid anatomical recovery and return of function and visual acuity in a single sitting.

Ocular Sarcoidosis Limited to Retinal Vascular Ischemia and Neovascularization.

A 59-year-old Caucasian male experienced progressive vision loss secondary to retinal vascular ischemia and neovascularization. At no time did he present with uveitis or vasculitis, and his serology tests were all negative. He was soon after diagnosed with sarcoidosis by hilar lymph node lung biopsy. Our patient demonstrates an atypical presentation of ocular sarcoidosis, manifesting solely as neovascularization and retinal vascular ischemia. Ophthalmologists should consider proliferative sarcoid retinopathy in patients with neovascularization.

Retinopathy and Uveitis Associated with Sofosbuvir Therapy for Chronic Hepatitis C Infection.

PURPOSE: We report a case of retinopathy and uveitis associated with sofosbuvir therapy for hepatitis C infection. METHODS: Case report. RESULTS: A 57-year-old-male developed ocular inflammation and retinopathy four weeks after the administration of sofosbuvir for a hepatitis C infection. Hearing loss, rheumatologic disease, and essential tremor were also noted. The ophthalmic findings resolved with discontinuation of the drug.    CONCLUSION:  The authors report a case of sofosbuvir induced retinopathy and uveitis, the first associated with this emerging therapy for hepatitis C. Ophthalmologists and other treating physicians should be aware of the ophthalmic side effects of this drug.

Correction: Retinopathy and Uveitis Associated with Sofosbuvir Therapy for Chronic Hepatitis C Infection.

[This corrects the article DOI: 10.7759/cureus.597.].

Intravitreal Injection-Induced Migraine Headaches.

A case of migraine headache triggered by intravitreal injection, and aborted by retrobulbar injection, is reported. To date, migraine and related cephalgia have not been reported after intravitreal injection. Ophthalmologists and neurologists should be aware of this potential sequela of a very common procedure.