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AIMS: To evaluate and compare the distribution of stress patterns around a single implant-supported crown with various abutment designs using different abutment materials. SETTING AND DESIGN: This is an in vitro study to evaluate and compare stress distribution patterns. METHODS: The three-dimensional (3D) finite element models included four stock and four customized abutments made of Titanium, Zirconia, Fibre-Reinforced Composite, and Poly Ether-Ether Ketone (PEEK) attached to an end-osseous root form implant. The models were subjected to a 300 N vertical load at the central fossa and a 150 N oblique load at the centre of the lingual inclines of the buccal cusps of the mandibular molar crown designed on the model. STATISTICAL ANALYSIS USED: The stress distribution within the implant and the surrounding supporting structures was evaluated using finite element analysis. RESULTS: In all the models, stresses on the implants were observed to be concentrated in the neck of the implants in the first few threads. Irrespective of the abutment design, PEEK abutment transferred greater stresses to implants and Zirconia abutment transferred lesser stresses to implants. In the implants, the customized abutment showed lesser stress values than the stock abutment during oblique loading. CONCLUSIONS: Stresses on implants and cortical bone can be reduced by using Zirconia as an abutment material compared to Titanium, Fibre-Reinforced Composite, and Poly Ether-Ether Ketone material. Customized abutments improve the load transfer between the prosthesis and the implant and the surrounding bone, lessen the micro-movement of the abutments, and distribute the stress more evenly across the implant's component parts.
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This is a retrospective series of five eyes of four cases with diabetic macular edema (DME) secondary to large capillary aneurysms. Larger capillary aneurysms were identified noninvasively based on the presence of white rim in color photograph. On optical coherence tomography (OCT), the larger capillary aneurysms were seen as vertically oval structures with heterogeneous lumen and hyperreflective margin. Two of the four eyes were treated with intravitreal therapy with poor response before considering laser photocoagulation. In one eye, laser photocoagulation was considered as primary therapy in view of the poor response to intravitreal therapy in the fellow eye. In one eye, intravitreal steroid with prompt laser was considered. In one eye, laser was considered as primary therapy. Complete obliteration of the capillary lumen was noted on OCT in all the five eyes after laser photocoagulation. Complete resolution of macular edema was noted in all the five eyes with no recurrence over a follow-up period of 4-18 months. DME secondary to larger capillary aneurysms responds well to targeted laser photocoagulation. These larger capillary aneurysms can be identified on clinical examination and color photograph by the presence of white rim and can be confirmed on OCT.
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PURPOSE: To report successful treatment of a hypofluorescent perifoveal exudative vascular anomalous complex (PEVAC)/capillary macroaneurysm. CASE DESCRIPTION: A 63 year old healthy gentleman had a perifoveal isolated aneurysmal lesion with white rim. Optical coherence tomography (OCT) showed cystoid macular edema (CME) with neurosensory detachment. The aneurysmal lesion was seen in the inner retina as a hyperreflective intraretinal structure with a heterogenous lumen suggestive of PEVAC/capillary macroaneurysm. OCT angiography showed a capillary loop and a slightly hyperreflective lesion at the tip of the loop in the superficial capillary plexus slab. Minimal reduction in edema was noted following one dose of intravitreal triamcinolone (2â mg). Fundus fluorescein angiography performed at 6 weeks demonstrated the capillary loop, but the aneurysmal lesion remained hypofluorescent with no definite leak in the late phase. Few perifoveal microaneurysms were seen in both the eyes. Six weeks later, focal laser photocoagulation of the aneurysmal lesion was performed, which resulted in complete resolution of macular edema at 1 month. There was no recurrence of macular edema till his recent follow up, which is 4 month post laser. DISCUSSION: PEVAC is typically described as unifocal lesion and is not associated with other retinal vascular abnormalities. But in this case, in addition to the lesion, perifoveal microaneurysms were seen in both the eyes. Despite the absence of leak on fundus fluorescein angiography, targeted focal laser photocoagulation resulted in complete resolution of macular edema at 1 month. CONCLUSION: Laser photocoagulation would be helpful even in hypofluorescent PEVAC/capillary macroaneurysms.
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PURPOSE: To describes one case of syphilitic necrotizing retinitis and one case of presumed syphilitic necrotizing retinitis with presence of subhyaloid hypopyon. CASE DESCRIPTION: We report two cases of necrotizing retinitis, which were noted to have yellow boat-shaped lesions at the inferior edge of retinitis resembling subhyaloid hypopyon. The subhyaloid location was confirmed on optical coherence tomography in one case. Both the cases were positive for venereal disease research laboratory test (VDRL) and Treponema pallidum hemagglutination (TPHA). But in one case, polymerase chain reaction (PCR) of the aqueous humor was positive for Pseudomonas aeruginosa and responded well to piperacillin. As piperacillin is effective against Pseudomonas and the efficacy of piperacillin in the management of syphilis is not studied, we may have to consider it as a case of presumed syphilitic retinitis. DISCUSSION: Subhyaloid hypopyon is an uncommon presentation and is reported in two cases of syphilitic necrotizing retinitis in literature. Severe infection and necrosis confined to the inner retina leads to collection of white blood cells and necrotic material in the subhyaloid space and would settle down resulting in subhyaloid hypopyon. Two cases of subhyaloid hypopyon reported in literature and 2 cases reported in our article are syphilitic retinitis and is not reported in other entities. CONCLUSION: It is possible that subhyaloid hypopyon may serve as a diagnostic cue in syphilitic necrotizing retinitis.
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Infecciones Bacterianas del Ojo , Retinitis , Sífilis , Humanos , Sífilis/diagnóstico , Sífilis/tratamiento farmacológico , Señales (Psicología) , Infecciones Bacterianas del Ojo/diagnóstico , Infecciones Bacterianas del Ojo/tratamiento farmacológico , PiperacilinaRESUMEN
Retinal drawing with a color-coding system brings uniformity in representation of fundus findings so that clinician can decipher various lesions on a two-dimensional drawing. Existing color coding addresses most of the common retinal pathologies including preretinal, intraretinal, and subretinal lesions. However, with the advent of various imaging modalities there is deeper understanding of microanatomy of retina and associated pathologies. With this, there appears further need of newer set of color coding to include the minute details of fundus findings clinically. Through this article, we discuss few common pathologies at different levels of retina layers with color-coding dilemma which calls for a better preciseness in its clinical representations.
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Retina , Color , Angiografía con Fluoresceína/métodos , Fondo de Ojo , Humanos , Retina/diagnóstico por imagen , Retina/patologíaRESUMEN
Revesz syndrome is a rare telomeropathy characterized by bone marrow failure and exudative retinopathy. We report the case of a 2-year-old male child, initially treated with bilateral laser photocoagulation for retinopathy of prematurity. He developed exudative changes in the right eye, presumed to be Coats disease. Later, the left eye developed a total vitreous hemorrhage. Proliferative retinopathy was noted intraoperatively. Systemic features of bone marrow failure, growth retardation, and nail pigmentation were present. Genetic testing confirmed the diagnosis of Revesz syndrome. We describe our approach to diagnosis and surgical management of the case. [Ophthalmic Surg Lasers Imaging Retina 2022;53(6): 346-348.].
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Enfermedades Óseas Metabólicas , Telangiectasia Retiniana , Médula Ósea/anomalías , Trastornos de Fallo de la Médula Ósea , Niño , Preescolar , Humanos , Recién Nacido , Masculino , RetinaRESUMEN
Carbon dioxide (CO2) and methane (CH4) are the most important greenhouse gases (GHGs) due to their significant role in anthropogenic global climate change. The spatio-temporal variations of their concentration are characterized by the terrestrial biosphere, seasonal weather patterns and anthropogenic emissions. Hence, to understand the variability in regional surface GHG fluxes, high precision GHGs measurements were initiated by the National Remote Sensing Center (NRSC) of India. We report continuous CO2 and CH4measurements during 2014 to 2017 for the first time from Shadnagar, a suburban site in India. Annual mean CO2 and CH4 concentrations are 399.56 ± 5.46 ppm and 1.929 ± 0.09 ppm, respectively, for 2017. After the strong El Niño of 2015-2016, an abnormal rise in CO2 growth rate of 5.5 ppm year-1 was observed in 2017 at the study site, compared to 3.03 ppm year-1 at Mauna Loa. Thus, the repercussion of the El Niño effect diminishes the net uptake by the terrestrial biosphere accompanied by increased soil respiration. Seasonal tracer to tracer correlation between CO2 and CH4 was also analyzed to characterize the possible source-sink relationship between the species. We compared CO2 and CH4 concentrations to simulations from an atmospheric chemistry transport model (ACTM). The seasonal phases of CH4 were well captured by the ACTM, whereas the seasonal cycle amplitude of CO2 was underestimated by about 30%.
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Dióxido de Carbono , Gases de Efecto Invernadero , Dióxido de Carbono/análisis , Gases de Efecto Invernadero/análisis , Metano/análisis , Óxido Nitroso/análisis , Estaciones del Año , SueloRESUMEN
In this study, we report the whole genome assembly of Bt 62, a novel isolate harbouring cry8 holotype gene identified by us earlier. Sequencing was carried out using a combination of Illumina NextSeq 500 and Oxford Nanopore sequencing Technologies (ONT). The final assembled genome was 6.13 Mb comprising a circular chromosome and four plasmids. The bioassay studies against Holotrichia serrata (F.) (Coleoptera: Scarabaeidae), a polyphagous pest infesting sugarcane and other crops, indicated significant toxicity to first instar grubs over untreated larvae achieving a highest mean mortality of 91.11% for various doses tested. In vitro proteolytic assay and histopathological studies of the midgut of infected white grubs revealed proteolytic processing of the protoxin and extensive degeneration of larval midgut epithelial cells. The results demonstrate that this novel isolate could be used as a biopesticide or its crystal toxin genes could be expressed in sugarcane and other crops for resistance against H. serrata.
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Bacillus thuringiensis , Escarabajos , Mariposas Nocturnas , Saccharum , Animales , Bacillus thuringiensis/genética , Proteínas Bacterianas/genética , Escarabajos/genética , Endotoxinas/genética , Endotoxinas/toxicidad , Proteínas Hemolisinas/genética , Larva/genética , Saccharum/genéticaRESUMEN
PURPOSE: Intravitreal anti-vascular endothelial growth factor (VEGF) injection therapy has emerged as the mainstay of treatment in the management of diabetic macular edema (DME) today. Various systemic risk factors have to be considered before initiating anti-VEGF therapy. The aim of our study was to form a consensus on various systemic factors to consider before starting anti-VEGF therapy for DME. METHODS: A questionnaire was created and sent across to various retina specialists across India. A GoogleTM form with various questions pertaining to what systemic parameters would one consider before giving anti-VEGF therapy for DME was sent to each of them by email/WhatsAppTM/direct telephonic interview. RESULTS: Of the 650 retina specialists contacted, 322 responded to the questionnaire. There was no difference in responses between private and institutional practitioners. The majority would consider RBS (85%), HbA1c (61%), blood pressure (63%), and renal function (57%) as a routine before administering the anti-VEGF injection, while the majority would not consider hemoglobin (63%) or lipid profile (55%) of the patient as a routine practice prior to administering the injection. CONCLUSION: In our study, most VR specialists prefer to consider RBS, HbA1c, BP, and renal profile (creatinine) routinely prior to anti-VEGF injection. We suggest that it is important to consider blood pressure control, glycemic control, HbA1c, Hb, lipid profile, and renal profile (UACR, eGFR, and creatinine) prior to anti-VEGF therapy in all diabetic patients and to discuss the need for statins in patients with dyslipidemias with the physician.
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Diabetes Mellitus , Retinopatía Diabética , Edema Macular , Inhibidores de la Angiogénesis/uso terapéutico , Retinopatía Diabética/complicaciones , Retinopatía Diabética/diagnóstico , Retinopatía Diabética/tratamiento farmacológico , Humanos , Inyecciones Intravítreas , Edema Macular/diagnóstico , Edema Macular/tratamiento farmacológico , Edema Macular/etiología , Ranibizumab/uso terapéutico , Retina , Encuestas y Cuestionarios , Factor A de Crecimiento Endotelial VascularRESUMEN
PURPOSE: To derive consensus statements for surgical management of proliferative diabetic retinopathy (PDR) for vitreoretinal (VR) surgeons. METHODS: Thirteen prolific VR surgeons representing all regions of India were invited to participate in a 42-point questionnaire based on the Delphi methodology describing various surgical scenarios commonly encountered in PDR. Consensus was derived using predefined robust analytics. Scenarios that returned a moderate consensus in round 1 were taken to round 2 as per the Delphi methodology. After considering all inputs, the final consensus criteria were developed. RESULTS: A strong consensus was derived about waiting for 4 weeks before considering vitrectomy. In treatment-naïve eyes with fresh vitreous hemorrhage (VH), the wait time was slightly shorter for extramacular tractional retinal detachment (2-4 weeks) and longer (4-6 weeks) for eyes treated previously with laser or anti-VEGF agents. The expert panel recommended using preoperative anti-VEGF only in eyes with large membranes requiring extensive dissection. For post vitrectomy VH, while a conservative approach was recommended for the first episode of VH, experts recommended immediate vitreous lavage for recurrent episodes of VH. In eyes with iris neovascularization, the panel recommended immediate anti-VEGF injection followed by early vitreous lavage in nonresponsive eyes. A strong consensus was derived for stopping antiplatelet agents before surgery, while there was only a moderate consensus for performing vitrectomy for recalcitrant macular edema unresponsive to anti-VEGF injections in the absence of traction. CONCLUSION: This study provides valuable consensus on managing the different scenarios encountered during surgical management of PDR and should help guide the VR surgeons in clinical decision-making.
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Diabetes Mellitus , Retinopatía Diabética , Consenso , Retinopatía Diabética/diagnóstico , Retinopatía Diabética/cirugía , Humanos , India/epidemiología , Vitrectomía , Hemorragia Vítrea/cirugíaRESUMEN
PURPOSE: To identify the predictors of final visual outcome in cases with post-fever retinitis (PFR). METHODS: This is a retrospective study of cases with diagnosis of post-fever retinitis. Colour fundus photograph and optical coherence tomography (OCT) parameters at presentation and final visit were analysed. Various factors at presentation [age, systemic illness, best-corrected visual acuity (BCVA), area of retinitis and hard exudates, OCT parameters], at final visit (OCT parameters) and the treatment modalities used were correlated with BCVA at final visit. RESULTS: Twenty-four eyes of 16 patients with PFR were included in the study. Median BCVA at presentation was 6/60 and at final visit was 6/9. By multiple linear regression after adjusting for other variables, for every 1 unit increase in height of subretinal fluid (SRF) at fovea at presentation, the value of final BCVA decreased by 0.001 unit. For every 1 unit increase in extent of ellipsoid zone (EZ) loss and subfoveal deposit height, the value of final BCVA decreased by 0.0001 unit and 0.004 unit, respectively. The baseline OCT parameters that had negative correlation with final BCVA included central macular thickness (r: - 0.5182, p: 0.02), maximum SRF height (r: - 0.5539, p < 0.01) and SRF height at fovea (r: - 0.582, p < 0.01). The OCT parameters at final visit which had a negative correlation with final BCVA included disorganisation of retinal inner layers (DRIL) within 1000 microns from centre of fovea (r: - 0.6494, p < 0.01), height of subfoveal deposit (r: - 0.7627, p < 0.01), horizontal extent of subfoveal deposit (r: - 0.6695, p < 0.01) and extent of EZ loss (r: - 0.8216, p < 0.01). CONCLUSION: Height of SRF at presentation, extent of EZ loss and subfoveal deposit height at final visit were associated with poor final BCVA in PFR.
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Retinitis , Tomografía de Coherencia Óptica , Fóvea Central , Humanos , Retinitis/diagnóstico , Estudios Retrospectivos , Agudeza VisualRESUMEN
The quest for auxiliary plasmonic materials with lossless properties began in the past decade. In the current study, a unique plasmonic response is demonstrated from a stratified high refractive index (HRI)-graphene oxide (GO) and low refractive index (LRI)-polymethyl methacrylate (PMMA) multistack. Graphene oxide plasmon-coupled emission (GraPE) reveals the existence of strong surface states on the terminating layer of the photonic crystal (PC) framework. The chemical defects in GO thin film are conducive for unraveling plasmon hybridization within and across the multistack. We have achieved a unique assortment of metal-dielectric-metal (MDM) ensuing a zero-normal steering emission on account of solitons as well as directional GraPE. This has been theoretically established and experimentally demonstrated with a metal-free design. The angle-dependent reflectivity plots, electric field energy (EFI) profiles, and finite-difference time-domain (FDTD) analysis from the simulations strongly support plasmonic modes with giant Purcell factors (PFs). The architecture presented prospects for the replacement of metal-dependent MDM and surface plasmon-coupled emission (SPCE) technology with low cost, easy to fabricate, tunable soliton [graphene oxide plasmon-coupled soliton emission (GraSE)], and plasmon [GraPE] engineering for diverse biosensing applications. The superiority of the GraPE platform for achieving 1.95 pg mL-1 limit of detection of human IFN-γ is validated experimentally. A variety of nanoparticles encompassing metals, intermetallics, rare-earth, and low-dimensional carbon-plasmonic hybrids were used to comprehend PF and cavity hot-spot contribution resulting in 900-fold fluorescence emission enhancements on a lossless substrate, thereby opening the door to unique light-matter interactions for next-gen plasmonic and biomedical technologies.