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Search Results: 1 - 10 of 141339 matches for " Ravi K Murthy "
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Aqueous Interleukin-6 (IL-6) Level Is a Marker for Treatment Resistance to Bevacizumab in Age-Related Macular Degeneration —Aqueous Cytokines after Bevacizumab  [PDF]
Kakarla V. Chalam, Sandeep Grover, Sankarathi Balaiya, Ravi K. Murthy
Open Journal of Ophthalmology (OJOph) , 2014, DOI: 10.4236/ojoph.2014.41005
Abstract:

Background: To prospectively evaluate the effect of intravitreal bevacizumab on aqueous levels of interleukin-6 (IL-6) and vascular endothelial growth factor (VEGF) in patients with exudative age-related macular degeneration (AMD) and to correlate clinical outcomes of patients and aqueous cytokine levels before and after injection. Methods: The study group consisted of 30 eyes from 30 patients with exudative AMD who underwent intravitreal injection of bevacizumab three times at monthly intervals. The aqueous samples prior to the 1st injection (baseline) and 3rd injection were analyzed for VEGF and IL-6 levels, evaluating the effect of 2 doses of intravitreal bevacizumab. Study patients were sub-grouped based upon change in central subfield (CSF) macular thickness on SD-OCT, at 8 weeks. Group 1 included patients (n = 14) with a decrease in CSF thickness greater than 10% from the baseline and were categorized to have improved. Group 2 included patients (n = 16) who had a decrease in CSF thickness 10% or less and were considered treatment-resistant. Results: There was no statistically significant change in aqueous VEGF and IL-6 levels after intravitreal bevacizumab. In sub-group analysis, in both Groups 1 and 2 patients, aqueous IL-6 levels showed a better correlation with CSF thickness on SD-OCT (r =

Spectral Domain OCT Documented Resolution of Pseudophakic Cystoid Macular Edema after Intravitreal Triamcinolone
Ravi K Murthy and Kakarla V. Chalam
Ophthalmology and Eye Diseases , 2012, DOI: 10.4137/OED.S3671
Abstract: Cystoid macular edema (CME) is an important cause of visual loss after cataract surgery. Treatment is usually with topical anti-inflammatory agents, with anti-vascular endothelial growth factor agents and steroids used intravitreally in resistant cases. Even though time-domain Stratus OCT can quantify the macular thickness, it cannot prognosticate visual outcomes due to the poor resolution of images, especially the outer segment-inner segment junction. Spectral-domain OCT (SD-OCT) by its ability to acquire large number of images in a short span of time provides high resolution cross-sectional images of the retina, which not only highlights the underlying pathological changes, but in addition can prognosticate visual recovery. We describe pre and post SD-OCT features of a case of refractory CME who was treated with intravitreal triamcinolone actetonide.
Spectral Domain OCT Documented Resolution of Pseudophakic Cystoid Macular Edema after Intravitreal Triamcinolone
Ravi K Murthy,Kakarla V. Chalam
Ophthalmology and Eye Diseases , 2010,
Abstract: Cystoid macular edema (CME) is an important cause of visual loss after cataract surgery. Treatment is usually with topical anti-inflammatory agents, with anti-vascular endothelial growth factor agents and steroids used intravitreally in resistant cases. Even though time-domain Stratus OCT can quantify the macular thickness, it cannot prognosticate visual outcomes due to the poor resolution of images, especially the outer segment-inner segment junction. Spectral-domain OCT (SD-OCT) by its ability to acquire large number of images in a short span of time provides high resolution cross-sectional images of the retina, which not only highlights the underlying pathological changes, but in addition can prognosticate visual recovery. We describe pre and post SD-OCT features of a case of refractory CME who was treated with intravitreal triamcinolone actetonide.
Limitations in assessing nerve growth factor levels in aqueous humor samples from human eyes
Kakarla V Chalam, Rajesh K Sharma, Ravi K Murthy
BMC Research Notes , 2008, DOI: 10.1186/1756-0500-1-22
Abstract: In this study, we examined the presence of NGF levels in aqueous humor collected from human eyes and the limitations in determining the NGF levels in human samples. NGF was assessed by ELISA immunoassay in undiluted aqueous samples collected from 32 consecutive patients undergoing surgery for cataract (control) or primary open angle glaucoma (POAG). Recombinant NGF was used as positive control. NGF levels were below undetectable levels in aqueous humor from eyes with POAG and controls by immunoassay. Less than 10% of samples had detectable NGF levels and these were considered outliers.Our result highlights the undetectable levels of NGF in human aqueous samples.Aqueous occupies the anterior and posterior chambers of the eye and nourishes the lens and the corneal endothelium. The aqueous composition resembles that of plasma, but contains much less proteins and glucose. It has higher levels of lactic and ascorbic acids. A number of studies have implicated nerve growth factor (NGF) in pathophysiology of glaucoma [1-3]. NGF receptors have been demonstrated on human trabecular meshwork [2,4] make it interesting to investigate changes in NGF levels in aqueous samples from patients. In this study we evaluated the feasibility of measuring NGF levels in aqueous samples using a commonly used ELISA kit.The study was approved by the Institutional Review Board, University of Florida, Jacksonville. An informed consent was obtained from all the patients included in the study. Aqueous samples were collected from 32 consecutive patients undergoing surgery for cataract (control) or primary open angle glaucoma (POAG). At the time of surgery, after preparing the eye, undiluted aqueous sample was collected from the anterior chamber by a 27 gauge insulin syringe. Samples were immediately frozen at -80°C and thawed immediately before assay. 18 patients had POAG and 14 patients had cataract.Most frequent sample size that could practically be collected (mode) was 50 μL of aqueous. ELISA imm
Functional microperimetry and SD-OCT confirm consecutive retinal atrophy from optic nerve pit
Vikram S Brar, Ravi K Murthy, K V Chalam
Clinical Ophthalmology , 2009, DOI: http://dx.doi.org/10.2147/OPTH.S7908
Abstract: nctional microperimetry and SD-OCT confirm consecutive retinal atrophy from optic nerve pit Case report (5127) Total Article Views Authors: Vikram S Brar, Ravi K Murthy, K V Chalam Published Date November 2009 Volume 2009:3 Pages 625 - 628 DOI: http://dx.doi.org/10.2147/OPTH.S7908 Vikram S Brar, Ravi K Murthy, K V Chalam University of Florida College of Medicine, Department of Ophthalmology, Jacksonville, FL, USA Abstract: A congenital anomaly, optic nerve pit is often associated with serous retinal detachment involving macula. Long standing serous detachment leads to outer retinal atrophy and decrease in visual sensitivity. Recently, spectral-domain optical coherence tomography (OCT) has been reported to demonstrate a communication between the optic nerve sheath and the subretinal space. Vitreous cavity is proposed as an alternate source of fluid for accumulation in the subretinal space. We imaged a patient with optic nerve pit with Spectralis OCT and report the findings seen including the presence of an area of peripapapillary retinal atrophy, due to the spontaneous resolution of associated long-standing retinal detachment.
Effects of Indocyanine green on cultured retinal ganglion cells in-vitro
S Balaiya, Vikram S Brar, Ravi K Murthy, KV Chalam
BMC Research Notes , 2009, DOI: 10.1186/1756-0500-2-236
Abstract: Cultured rat retinal ganglion cells (RGC-5) were exposed to different concentrations of ICG (0.25, 0.5, 1.0, 1.25, & 5 mg/ml) and at various time intervals (1, 5, 15, 30, & 60 minutes). Changes in structural morphology were identified using phase contrast bright field microscopy. Cell viability was quantified using the neutral red assay and cell death was characterized using Annexin-V staining.Significant morphologic changes were observed at the 15 and 60 min intervals for all concentrations, where a reduction in cell size and loss of normal spindle shape was noted. A dose dependent decrease in cell viability was observed with increasing concentration of ICG as well as increasing exposure intervals. Compared to control, 48-74% reduction in neutral red uptake at all concentrations for exposures 5 min or greater (p < 0.001). Even at 1 min exposure, a dose dependent decline was observed in cell viability, with a 28-48% decline for doses above 1.25 mg/ml (p = 0.007). Staining with Annexin-V, demonstrated a similar dose and time dependent increase in number of cells exhibiting early apoptosis. A greater than two-fold increase in Annexin-V expression for all doses at exposures greater than 1 min was noted.ICG dye exhibits toxicity to retinal ganglion cells at clinically relevant doses following 1 min exposure.Indocyanine green (ICG) is commonly used to stain the internal limiting membrane (ILM) [1,2] during macular surgery for the treatment of idiopathic macular holes [3-5] and diffuse diabetic macular edema [6]. However, the safety of intravitreal use of ICG is not well established. Adverse effects such as visual field defects [7-9] and atrophy of the retinal ganglion cell layer [10] subsequent to ICG assisted membrane peeling have been reported. The underlying cause of ICG-related adverse effects has been proposed to be due to the osmolarity of the solution [11] or photochemical damage [12].The retinal ganglion cell (RGC) layer is the first to come in contact with ICG d
Freezing adversely affects measurement of vascular endothelial growth factor levels in human aqueous samples
Sankarathi Balaiya, Sandeep Grover, Ravi K Murthy, et al
Clinical Ophthalmology , 2011, DOI: http://dx.doi.org/10.2147/OPTH.S15837
Abstract: eezing adversely affects measurement of vascular endothelial growth factor levels in human aqueous samples Original Research (3283) Total Article Views Authors: Sankarathi Balaiya, Sandeep Grover, Ravi K Murthy, et al Published Date January 2011 Volume 2011:5 Pages 81 - 85 DOI: http://dx.doi.org/10.2147/OPTH.S15837 Sankarathi Balaiya Sandeep Grover Ravi K Murthy Kakarla V Chalam Department of Ophthalmology, University of Florida College of Medicine, Jacksonville, FL, USA Purpose: Aqueous levels of vascular endothelial growth factor (VEGF) can be a surrogate marker of intraocular VEGF activity and a measure of efficacy of anti-VEGF treatment in a variety of vasoproliferative retinal disorders, including diabetic retinopathy, age-related macular degeneration, and central retinal vein occlusion. Measurement of the VEGF level may be adversely affected by premeasurement variables, such as freezing and delay, in sample analysis. We aim to evaluate the effect of storage and delayed measurement of human aqueous VEGF levels in these conditions. Methods: Aqueous samples collected from patients receiving intravitreal injection of bevacizumab for various retinal diseases were divided into two groups. In Group 1, the VEGF levels were analyzed on the same day; in Group 2, the VEGF levels were analyzed after 21 days of freezer storage (-80°C) using immunobead assay. Statistical comparison using a paired t-test was performed between the two groups. Results: Thirty-one aqueous humor samples were collected, and the VEGF concentration for fresh samples was 7.8 ± 5.9 pg/mL (mean ± SD) compared to 6.5 ± 6.0 pg/mL in frozen samples, resulting in a statistically significant difference (P = 0.03). Conclusions: Accurate measurement of the VEGF level is a vital component of clinical decision-making. Delayed analysis of VEGF levels in aqueous samples may result in significant sample degradation and lower levels of measured VEGF.
Evaluation of ultraviolet light toxicity on cultured retinal pigment epithelial and retinal ganglion cells
Sankarathi Balaiya, Ravi K Murthy, Vikram S Brar, et al
Clinical Ophthalmology , 2010, DOI: http://dx.doi.org/10.2147/OPTH.S7979
Abstract: luation of ultraviolet light toxicity on cultured retinal pigment epithelial and retinal ganglion cells Original Research (4752) Total Article Views Authors: Sankarathi Balaiya, Ravi K Murthy, Vikram S Brar, et al Published Date January 2010 Volume 2010:4 Pages 33 - 39 DOI: http://dx.doi.org/10.2147/OPTH.S7979 Sankarathi Balaiya, Ravi K Murthy, Vikram S Brar, Kakarla V Chalam Department of Ophthalmology, University of Florida College of Medicine, Jacksonville, FL, USA Purpose: Our study is aimed at evaluating the role of UVB light in inducing cytotoxicity in an in vitro model. Methods: RGC-5 and ARPE-19 cells were exposed to different time periods of UVB light: 0, 15, 30, and 45 min. They were subsequently examined for changes in cell morphology, cell viability (neutral red uptake assay), generation of reactive oxygen species (ROS), expression of bax, bcl-2 and cytochome C by reverse transcriptase polymerase chain reaction and western blot, respectively. Results: Dose-dependent reduction in cell viability to UVB light was demonstrated with parallel increase in ROS. Increased duration of exposure (>15 minutes), was associated with increased expression of bax and cytochrome C, and absence of bcl-2 expression. Conclusion: UVB light exposure results in cell cytotoxicity. The concomitant generation of ROS and expression of apoptotic markers suggests the role of oxidative stress in UVB-mediated apoptosis in an in vitro model of retinal ganglion and pigment epithelial cells.
The effect of supercharging on performance and emission characteristics of C.I. Engine with diesel-ethanol-ester blends
Donepudi Jagadish,Puli Ravi Kumar,Murthy Madhu K.
Thermal Science , 2011, DOI: 10.2298/tsci100513042d
Abstract: Biofuels like ethanol, biodiesel, have attracted attention of people worldwide and proved to be the successful fuel alternates to petroleum products. In the present investigation, the effect of supercharging is studied on the performance of a direct injection diesel engine using ethanol diesel blends with palm stearin methyl ester as additive. The performance of the engine is evaluated in terms of brake specific fuel consumption, thermal efficiency, exhaust gas temperature, un-burnt hydrocarbons, carbon monoxide, nitrogen oxide emissions, and smoke opacity. The investigation results showed that the output and torque performance of the engine with supercharging was improved in comparison with naturally aspirated engine. It is observed that the brake thermal efficiency of ethanol diesel blends was higher than that of diesel. With supercharging brake thermal efficiency is further improved. Brake specific fuel consumption of ethanol, ester and diesel blends are lower compared with diesel at full load. Further reduction in brake specific fuel consumption is observed with supercharging. Nitrous oxide formation seems to decrease with ethanol, ester and diesel blends. Hydrocarbons and carbon monoxide emissions are more with ethanol, ester and diesel blends with supercharging slight reduction in those values are observed.
Development and characterization of polymeric microspheres for controlled release protein loaded drug delivery system
Ravi S,Peh K,Darwis Yusrida,Murthy B
Indian Journal of Pharmaceutical Sciences , 2008,
Abstract: The aim of the present work was to investigate the preparation of microspheres as potential drug carriers for proteins, intended for controlled release formulation. The hydrophilic bovine serum albumin was chosen as a model protein to be encapsulated within poly(D,L-lactide-co-glycolide) (50:50) microspheres using a w/o/w double emulsion solvent evaporation method. Different parameters influencing the particle size, entrapment efficiency and in vitro release profiles were investigated. The microspheres prepared with different molecular weight and hydrophilicity of poly(D,L-lactide-co-glycolide) polymers were non porous, smooth surfaced and spherical in structure under scanning electron microscope with a mean particle size ranging from 3.98 to 8.74 μm. The protein loading efficiency varied from 40 to 71% of the theoretical amount incorporated. The in vitro release profile of bovine serum albumin from microspheres presented two phases, initial burst release phase due to the protein adsorbed on the microsphere surface, followed by slower and continuous release phase corresponding to the protein entrapped in polymer matrix. The release rate was fairly constant after an initial burst release. Consequently, these microspheres can be proposed as new controlled release protein delivery system.
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