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Holekamp N, Gentile B, Giocanti-Aurégan A, Garcia-Layana A, Peto T, Viola F, Kertes PJ, Mirt M, Kotecha A, Lambert J, Lewis HB, Chi GC. Patient Experience Survey Of Anti-VEGF Treatment for Neovascular Age-Related Macular Degeneration and Diabetic Macular Edema. Ophthalmic Res 2024:000538975. [PMID: 38679018 DOI: 10.1159/000538975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 04/13/2024] [Indexed: 05/01/2024]
Abstract
INTRODUCTION Understanding patient perspectives of treatment may improve adherence and outcomes. This study explored real-world patient experiences with anti-vascular endothelial growth factor (anti-VEGF) treatment for diabetic macular edema (DME) and neovascular age-related macular degeneration (nAMD). METHODS This multinational, non-interventional, quantitative, cross-sectional, observational survey assessed treatment barriers/burden, patient-reported visual functioning, and treatment satisfaction in DME and nAMD patients in the United States, United Kingdom, Canada, France, Italy, and Spain. Treatment patterns and visual outcomes were extracted from medical charts. Regression models evaluated relationships between adherence, total missed visits, number of anti-VEGF injections and clinical and patient-reported outcomes for visual functioning. Association between treatment satisfaction and aspects of burden were assessed. RESULTS The survey was completed by 183 DME and 391 nAMD patients. Patients had moderately high vision-related functioning (25-item National Eye Institute Visual Functioning Questionnaire score: mean=74.8) and were satisfied with their current treatment (mean total score: Macular Disease Treatment Satisfaction Questionnaire=59.2; Retinopathy Treatment Satisfaction Questionnaire=61.3). Treatment satisfaction scores were worse with higher time-related impacts of treatment (nAMD/DME), higher impacts on finances and daily life (nAMD), negative impact on employment and lower expectations for treatment effectiveness (DME). Most patients reported ≥1 barrier (66.1% DME, 49.2% nAMD patients) related to treatment (35.0%), clinic (32.6%), and COVID-19 (21.1%). Moreover, 44.9% of patients reported some impairment in activities of daily living. Work absenteeism was observed among >60% of working patients. Nearly one-quarter (24.2%) of patients needed ≥1 day to recover from intravitreal injections; most reported ≥30 minutes of travel time (73.7%) and clinic wait time (54.2%). In unadjusted univariable analyses, treatment adherence (vs non adherence) was related to higher most recent visual acuity (β = 8.98 letters; CI, 1.34-16.62) and lower odds of visual acuity below driving vision (≤ 69 letters) (OR = 0.50; CI, 0.25-1.00) . CONCLUSION More durable treatments with reduced frequency of injections/visits may reduce treatment burden and improve patient satisfaction, which may enhance adherence and visual outcomes.
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Rahimy E, Khan MA, Ho AC, Hatfield M, Nguyen TH, Jones D, McKeown A, Borkar D, Leng T, Ribeiro R, Holekamp N. Progression of Geographic Atrophy: Retrospective Analysis of Patients from the IRIS® Registry (Intelligent Research in Sight). Ophthalmol Sci 2023; 3:100318. [PMID: 37274013 PMCID: PMC10232896 DOI: 10.1016/j.xops.2023.100318] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 03/13/2023] [Accepted: 04/11/2023] [Indexed: 06/06/2023]
Abstract
Purpose To evaluate disease progression and associated vision changes in patients with geographic atrophy (GA) secondary to age-related macular degeneration (AMD) in 1 eye and GA or neovascular AMD (nAMD) in the fellow eye using a large dataset from routine clinical practice. Design Retrospective analysis of clinical data over 24 months. Subjects A total of 256 635 patients with GA from the American Academy of Ophthalmology (Academy) IRIS® Registry (Intelligent Research in Sight) Registry (January 2016 to December 2017). Methods Patients with ≥ 24 months of follow-up were grouped by fellow-eye status: Cohort 1, GA:GA; Cohort 2, GA:nAMD, each with (subfoveal) and without subfoveal (nonsubfoveal) involvement. Eyes with history of retinal disease other than AMD were excluded. Sensitivity analysis included patients who were managed by retina specialists and had a record of imaging within 30 days of diagnosis. Main Outcome Measures Change in visual acuity (VA), occurrence of new-onset nAMD, and GA progression from nonsubfoveal to subfoveal. Results In total, 69 441 patients were included: 44 120 (64%) GA:GA and 25 321 (36%) GA:nAMD. Otherwise eligible patients (57 788) were excluded due to follow-up < 24 months. In both GA:GA and GA:nAMD cohorts, nonsubfoveal study eyes had better mean (standard deviation) VA at index (67 [19.3] and 66 [20.3] letters) than subfoveal eyes (59 [23.9] and 47 [26.9] letters), and 24-month mean VA changes were similar for nonsubfoveal (-7.6 and -6.2) and subfoveal (-7.9 and -6.5) subgroups. Progression to subfoveal GA occurred in 16.7% of nonsubfoveal study eyes in the GA:GA cohort and 12.5% in the GA:nAMD cohort. More new-onset study-eye nAMD was observed in the GA:nAMD (21.6%) versus GA:GA (8.2%) cohorts. Sensitivity analysis supported the robustness of the observations in the study. Conclusions This retrospective analysis describes the natural progression of GA lesions and the decline in VA associated with the disease. Financial Disclosures Proprietary or commercial disclosure may be found after the references.
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Affiliation(s)
- Ehsan Rahimy
- Palo Alto Medical Foundation, Palo Alto, California
- Byers Eye Institute at Stanford, Stanford University School of Medicine, Palo Alto, California
| | - M. Ali Khan
- Wills Eye Hospital, Philadelphia, Pennsylvania
| | - Allen C. Ho
- Wills Eye Hospital, Philadelphia, Pennsylvania
| | | | | | - Daniel Jones
- Apellis Pharmaceuticals, Inc, Waltham, Massachusetts
| | - Alex McKeown
- Apellis Pharmaceuticals, Inc, Waltham, Massachusetts
| | - Durga Borkar
- Duke University School of Medicine, Durham, North Carolina
| | - Theodore Leng
- Byers Eye Institute at Stanford, Stanford University School of Medicine, Palo Alto, California
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Sharma A, Holz FG, Regillo CD, Freund KB, Sarraf D, Khanani AM, Baumal C, Holekamp N, Tadayoni R, Kumar N, Parachuri N, Kuppermann BD, Bandello F, Querques G, Loewenstein A, Özdek Ş, Rezai K, Laurent K, Bilgic A, Lanzetta P, Zur D, Yannuzzi N, Corradetti G, Kaiser P, Hilely A, Boyer D, Rachitskaya A, Chakravarthy U, Wintergerst M, Sarao V, Parolini B, Mruthyunjaya P, Nguyen QD, Do D, Keane PA, Hassan T, Sridhar J, Eichenbaum D, Grewal D, Splitzer M. Biosimilars for retinal diseases: United States-Europe awareness survey (Bio-USER - survey). Expert Opin Biol Ther 2023; 23:851-859. [PMID: 36726203 DOI: 10.1080/14712598.2023.2176218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 01/31/2023] [Indexed: 02/03/2023]
Abstract
PURPOSE To assess the awareness of biosimilar intravitreal anti-VEGF agents among retina specialists practicing in the United States (US) and Europe. METHODS A 16-question online survey was created in English and distributed between Dec 01, 2021 and Jan 31, 2022. A total of 112 respondents (retinal physicians) from the US and Europe participated. RESULTS The majority of the physicians (56.3%) were familiar with anti-VEGF biosimilars. A significant number of physicians needed more information (18.75%) and real world data (25%) before switching to a biosimilar. About one half of the physicians were concerned about biosimilar safety (50%), efficacy (58.9 %), immunogenicity (50%), and their efficacy with extrapolated indications (67.8 %). Retinal physicians from the US were less inclined to shift from off-label bevacizumab to biosimilar ranibizumab or on-label bevacizumab (if approved) compared to physicians from Europe (p=0.0001). Furthermore, physicians from the US were more concerned about biosimilar safety (p=0.0371) and efficacy compared to Europe (p= 0.0078). CONCLUSIONS The Bio-USER survey revealed that while the majority of retinal physicians need additional information regarding the safety, efficacy and immunogenicity when making clinical decisions regarding their use. Retinal physicians from US are more comfortable in continuing to use off-label bevacizumab compared to physicians from Europe.
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Affiliation(s)
| | - Frank G Holz
- Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Carl D Regillo
- The Retina Service of Wills Eye Hospital, Philadelphia, Pennsylvania, USA
| | - K Bailey Freund
- Vitreous Retina Macula Consultants of New York, New York, USA
- Department of Ophthalmology, NYU Grossman School of Medicine, New York, NY, USA
| | - David Sarraf
- Stein Eye Institute, UCLA, Los Angeles, CA, USA
- Department of Ophthalmology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Arshad M Khanani
- Sierra Eye Associates, Reno, NV, USA and The University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Caroline Baumal
- Tufts University School of Medicine, New England Eye Center, Boston, Massachusetts
| | | | - Ramin Tadayoni
- Université Paris Cité, AP-HP, Lariboisière, St Louis and Fondation Adolphe de Rothschild hospitals, Paris, France
| | | | | | - Baruch D Kuppermann
- Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, USA
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Merrill PT, Holekamp N, Roth D, Kasper J, Grigorian R. Corrigendum to "The 0.19-mg Fluocinolone Acetonide Intravitreal Implant Reduces Treatment Burden in Diabetic Macular Edema" [Am J Ophthalmol 2023;248;16-23]. Am J Ophthalmol 2023:S0002-9394(23)00194-0. [PMID: 37225642 DOI: 10.1016/j.ajo.2023.05.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Affiliation(s)
- Pauline T Merrill
- From the Department of Ophthalmology, Rush University, Chicago, Illinois (P.T.M.).
| | | | - Daniel Roth
- Department of Ophthalmology, Rutgers-Robert Wood Johnson Medical School, New Brunswick, New Jersey (D.R.)
| | | | - Ruben Grigorian
- Northeast Louisiana Retina Eye Center, West Monroe, Louisiana (R.G.), USA
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Merrill PT, Holekamp N, Roth D, Kasper J, Grigorian R. The 0.19-mg Fluocinolone Acetonide Intravitreal Implant Reduces Treatment Burden in Diabetic Macular Edema. Am J Ophthalmol 2023; 248:16-23. [PMID: 36223849 DOI: 10.1016/j.ajo.2022.09.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 09/12/2022] [Accepted: 09/17/2022] [Indexed: 02/06/2023]
Abstract
PURPOSE To assess treatment burden in patients with diabetic macular edema (DME) after the 0.19-mg fluocinolone acetonide (FAc) intravitreal implant (ILUVIEN). DESIGN Prospective and retrospective analyses of a 36-month, phase 4, open-label, observational study. METHODS Setting: Multicenter. PATIENT POPULATION Included patients had DME and previously received corticosteroid treatment without a clinically significant rise in intraocular pressure (IOP) (N = 202 eyes in 159 patients). Patients were not randomized. OBSERVATION PROCEDURES Prospective, observational treatment burden data were analyzed for their relationship to safety and functional efficacy outcomes across 36 months. MAIN OUTCOME MEASURES Outcomes included the mean number of yearly treatments, supplemental-free probability over time, best-corrected visual acuity, and monitoring of IOP-related events. RESULTS Over 36 months, the mean number of yearly treatments decreased from 3.5 before FAc to 1.7 after FAc; at 36 months, 68.3% of patients required 0 to 2 treatments per year. After FAc, the percentage of eyes requiring supplemental therapy decreased vs before FAc (P < .0001 for each). Through 36 months, 25% of FAc-treated eyes did not require supplemental treatment. At 36 months, mean best-corrected visual acuity increased by 4.5 letters vs a decline of 6.4 letters in the 36 months before FAc. IOP elevations >25 mm Hg occurred in 18.2% of eyes that did not receive supplemental treatment after FAc vs 27.2% of eyes that received supplemental treatments, which included additional intraocular steroids. CONCLUSIONS Over 36 months, the FAc implant is associated with improved visual outcomes and better disease control as measured by a significant reduction in yearly treatment burden in patients with DME.
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Affiliation(s)
- Pauline T Merrill
- From the Department of Ophthalmology, Rush University, Chicago, Illinois (P.T.M.).
| | | | - Daniel Roth
- Department of Ophthalmology, Rutgers-Robert Wood Johnson Medical School, New Brunswick, New Jersey (D.R.)
| | | | - Ruben Grigorian
- Northeast Louisiana Retina Eye Center, West Monroe, Louisiana (R.G.), USA
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Holekamp N, Duff SB, Rajput Y, Garmo V. Cost-effectiveness of ranibizumab and aflibercept to treat diabetic macular edema from a US perspective: analysis of 2-year Protocol T data. J Med Econ 2020; 23:287-296. [PMID: 31502893 DOI: 10.1080/13696998.2019.1666855] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Aims: Protocol T (NCT01627249) was a head-to-head study conducted by the Diabetic Retinopathy Clinical Research Network that compared intravitreal aflibercept, bevacizumab, and ranibizumab for the treatment of diabetic macular edema (DME). A cost-effectiveness analysis accompanying the 1-year data of Protocol T revealed that aflibercept was not cost-effective vs ranibizumab for all patients, but could have been cost-effective in certain patient sub-groups if the 1-year results were extrapolated out to 10 years. The present study evaluated the cost-effectiveness of US Food and Drug Administration-approved anti-vascular endothelial growth factor agents (ranibizumab, aflibercept) for treatment of DME using the 2-year data from Protocol T.Methods: Costs of aflibercept 2.0 mg or ranibizumab 0.3 mg, visual acuity (VA)-related medical costs, and quality-adjusted life-years (QALYs) were simulated for eight VA health states. Treatment, adverse event management, and VA-related healthcare resource costs (2016 US dollars) were based on Medicare reimbursement and published literature. VA-related health utilities were determined using a published algorithm. Patients were stratified by baseline VA: 20/40 or better; 20/50 or worse.Results: Total 2-year costs were higher, and QALYs similar, for aflibercept vs ranibizumab in the full cohort ($44,423 vs $34,529; 1.476 vs 1.466), 20/40 or better VA sub-group ($40,854 vs $31,897; 1.517 vs 1.519), and 20/50 or worse VA sub-group ($48,214 vs $37,246; 1.433 vs 1.412), respectively. Incremental cost-effectiveness ratios in the full cohort and 20/50 or worse VA sub-group were $986,159/QALY and $523,377/QALY, respectively. These decreased to $711,301 and $246,978 when analyses were extrapolated to 10 years.Limitations: Key potential limitations include the fact that VA was the only QALY parameter analyzed and the uncertainty surrounding the role of better- and worse-seeing eye VA in overall functional impairment.Conclusions: This analysis suggests that aflibercept is not cost-effective vs ranibizumab for patients with DME, regardless of baseline vision.
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Affiliation(s)
| | - Steven B Duff
- Veritas Health Economics Consulting, Inc., Carlsbad, CA, USA
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Werther W, Chu L, Holekamp N, Do DV, Rubio RG. Myocardial infarction and cerebrovascular accident in patients with retinal vein occlusion. ACTA ACUST UNITED AC 2011; 129:326-31. [PMID: 21402990 DOI: 10.1001/archophthalmol.2011.2] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVE To compare the incidence rates of myocardial infarction (MI) and cerebrovascular accident (CVA) in hospitalized patients with and without branch or central retinal vein occlusion (RVO). METHODS In this retrospective cohort study, a US population-based health care claims database was used to identify patients with RVO and control patients, matched for age and sex. Events of MI, CVA, and covariates were identified for patients with and without RVO. Incidences of MI or CVA events prompting hospitalization and adjusted rate ratios (RRs) were calculated; RRs were adjusted for covariates consistent with risk factors for outcomes. RESULTS Of 4500 patients with RVO and 13,500 controls, the event rates for MI were 0.87 per 100 person-years and 0.67 per 100 person-years, respectively. The adjusted RR for MI was 1.03 (95% confidence interval [CI], 0.75-1.42; P = .85 for RVO vs controls). Event rates for CVA were 1.16 and 0.52 per 100 person-years for RVO and controls, respectively. The adjusted RR for CVA was 1.72 (95% CI, 1.27-2.34; P = .001) for RVO vs controls. CONCLUSIONS This study provides quantitative data on the incidence of cardiovascular and cerebrovascular outcomes in patients with RVO in a large US population-based health care claims database. Event rates for MI were similar in patients with RVO and controls; however, the event rate for CVA in patients with RVO was almost 2-fold that observed in controls.
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Mann AL, Bressler SB, Hawkins BS, Holekamp N, Bressler NM. Comparison of methods to identify incident cataract in eyes of patients with neovascular maculopathy: Submacular Surgery Trials Report No. 18. Ophthalmology 2007; 115:127-33. [PMID: 17574675 DOI: 10.1016/j.ophtha.2007.03.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2006] [Revised: 03/03/2007] [Accepted: 03/05/2007] [Indexed: 11/16/2022] Open
Abstract
PURPOSE To describe and compare methods used to monitor development and progression of presumed vision-limiting lens opacity in study eyes of Submacular Surgery Trials (SST) patients. DESIGN Prospective study of patients enrolled in a set of randomized clinical trials. PARTICIPANTS Patients enrolled in the SST who were phakic in the study eye at the time of enrollment (n = 690). In a subset of 114 patients, lens photographs were obtained at baseline and 2 years after enrollment. METHODS Data collection at baseline and annual follow-up examinations included ocular history, ophthalmologic examination including the SST ophthalmologist's assessment of presence or absence of vision-limiting opacity, fundus photography, and lens photography (13 of 27 clinics only). All photographs were assessed by masked graders centrally using the Lens Opacities Classification System III (LOCS III). kappa statistics were calculated to compare LOCS III cataract classifications with fundus photograph quality and with the ophthalmologist's assessment of lens opacity, with the LOCS III classification considered the gold standard. MAIN OUTCOME MEASURE Incidence of cataract in study eyes. RESULTS Baseline lens photographs were available and graded for 312 (45%) of 690 patients with phakic study eyes; 2-year lens photographs were available for 156 (23%) of 690 initially phakic eyes. Both baseline and 2-year lens photographs were available for 114 eyes that remained phakic. Submacular surgery was associated with significant progression of nuclear color and nuclear opalescence characteristics within 2 years of enrollment. The reliability of fundus photograph quality versus cataract classification using a 4.5 LOCS III score threshold for cataract was poor to good at each time point and for all groups (kappa, 0-0.51), but sensitivity of the photograph quality score as a surrogate was low, and both positive and negative predictive values were low. Agreement between the ophthalmologists' assessments of lens opacity and the 4.5 LOCS III score threshold for cataract was good (kappa, 0.42-0.78). CONCLUSIONS In the SST, clinical identification of severe cataract (LOCS III scores of 4.5 or worse for nuclear opacity or nuclear color) by the examining ophthalmologist was valid based on comparison with LOCS III scores and may be an adequate method to use in similar trials.
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Sheidow TG, Blinder KJ, Holekamp N, Joseph D, Shah G, Grand MG, Thomas MA, Bakal J, Sharma S. Outcome results in macular hole surgery: an evaluation of internal limiting membrane peeling with and without indocyanine green. Ophthalmology 2003; 110:1697-701. [PMID: 13129864 DOI: 10.1016/s0161-6420(03)00562-1] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
PURPOSE To evaluate the anatomic closure rate and visual outcome in patients undergoing pars plana vitrectomy (PPV) with internal limiting membrane (ILM) peeling with and without indocyanine green (ICG) enhancement. DESIGN Retrospective, noncomparative interventional case series. PARTICIPANTS One hundred ninety-three consecutive patients (204 eyes) seen at the Barnes Retina Institute with the clinical diagnosis of macular hole who underwent PPV between January 1998 and December 2000. INTERVENTION A consecutive series of 97 patients undergoing PPV with or without unilateral epiretinal membrane removal without ILM peeling (group 1), 44 patients with PPV and ILM peeling without ICG (group 2), and 35 patients with ICG-assisted ILM peeling (group 3). RESULTS Overall, 86.4% of the holes closed with one operation, with 75 of 97 (77.3%) eyes in group 1, 43 of 44 (97.7%) eyes in group 2, and 34 of 35 (97.1%) eyes in group 3 (chi(2)= 10.51, P = 0.007). Of the eyes that did not close, 18 patients in group 1 underwent repeat surgery, with 90 of 97 (92.8%) eyes ultimately achieving closure. Visual acuity after surgery was 20/50 or better in 55 of 97 (56.7%) patients, 31 of 44 (70.4%) patients, and 18 of 35 (51.4%) patients in groups 1, 2, and 3, respectively (chi(2) = 3.43, P = 0.18) and increased by 2 or more lines from their preoperative status in 63 of 97 (64.9%) patients, 34 of 44 (77.3%) patients, and 25 of 35 (71.4%) patients, respectively (chi(2)= 2.25, P = 0.32). Multivariate logistic regression demonstrated that use of ILM peeling during vitrectomy increases the chances of developing 20/50 vision or better (odds ratio [OR], 2.4; 95% confidence interval, 1.06-5.45; P = 0.04). No eyes received concurrent cataract extraction with macular hole surgery, but 75 of 166 (45.2%) required cataract extraction postoperatively. Complications included 20 retinal tears, 4 retinal detachments, and 34 patients with postoperative elevations in intraocular pressure (IOP; defined as IOP greater than 30 mmHg). CONCLUSIONS Although this study is limited by the shorter follow-up in patients undergoing ILM peeling with or without ICG relative to the control group, our experience indicates that the use of ILM peeling is associated with a statistically significant improvement in the rate of primary macular hole closure with a single operation.
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Affiliation(s)
- Tom G Sheidow
- Department of Ophthalmology, University of Western Ontario, London, Ontario, Canada
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Abstract
We delineated the ontogeny of the brain insulin binding, insulin receptor number and affinity using plasma membranes isolated from the rabbit. Specific 125I-insulin binding and receptor number expressed per milligram of protein increased from the 20 day gestation fetus to the 1-day-old newborn, declining thereafter to attain adult values by day 6 of postnatal life. Specific 125I-insulin binding and the receptor number in the adult brain was less than the fetal and neonatal (1 day) brain receptors. Although a similar trend was observed specifically during fetal development, the changes in receptor number expressed per microgram DNA were not significant in the neonatal period. The adult brain insulin receptor number was higher than the 20- to 27-day fetus and similar to that of the 30-day fetus and the 1- to 5-day newborns. The total receptor number correlated linearly with the brain plasma membrane protein increment velocity. The affinity of the receptors increased during early fetal development (20-27 days) and remained constant thereafter in the postnatal period. We conclude that the ontogenic changes of the brain insulin receptors are similar to the ontogenic changes of brain plasma membrane protein. The developmental changes are more pronounced when the receptor number is expressed per milligram protein versus microgram DNA.
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Devaskar SU, Holekamp N, Marino N, Devaskar UP. Altered thyroidal states modulate the insulin receptor characteristics of the developing rabbit brain. Dev Pharmacol Ther 1986; 9:350-60. [PMID: 3536365 DOI: 10.1159/000457113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
We investigated the effect of propylthiouracil (PTU)-induced hypothyroidism and T4-induced hyperthyroidism on the fetal and neonatal rabbit brain insulin receptors (number and affinity) using plasma membranes. PTU administration to the pregnant mothers resulted in low serum-free T4 and normal total T3 concentrations, while T4 therapy to the mothers resulted in high serum-free T4 and high total T3 concentrations in the fetus and neonate. PTU-induced hypothyroidism did not affect the fetal brain insulin receptors, cholesterol content (brain homogenate) or protein content. On the other hand, brain insulin receptor number and total brain cholesterol content decreased in the neonate. T4 therapy at 100 micrograms/kg reversed the serum T4 to the control value and normalized the neonatal brain insulin receptor number and cholesterol content while a higher dose of T4 (200 micrograms/kg) increased the neonatal brain insulin receptor number, cholesterol and protein content. We conclude that altered thyroidal states modulate the brain insulin receptor (number and affinity) in neonatal, but not fetal brain plasma membranes.
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Abstract
Insulin (2U-regular) was administered intracerebrally or intraperitoneally in newborn rabbit pups, to study the effect of the hormone on brain insulin receptor characteristics. Intraperitoneal insulin treatment produced an increase in plasma insulin concentrations from a control of approximately 24 microU/ml to 132 +/- 36 (p less than 0.02) and a decrease in plasma glucose from approximately 83 to 27 +/- 10 mg/dl (p less than 0.01). No change in brain insulin receptor characteristics was observed. On the other hand, insulin injected intracerebrally raised the plasma insulin to greater than 3000 microU/ml and lowered the plasma glucose to 32 +/- 8 mg/dl (p less than .05). In addition a decrease in brain insulin receptor sites from 262 +/- 9 X 10(10) mg protein-1 to 159 +/- 6 (p less than 0.001) was noted. When the data was expressed per microgram DNA, a decrease from 4 +/- 0.4 X 10(10) to 2.5 +/- 0.2 (p less than .01) in receptor sites resulted. No change in the receptor affinity was observed. We conclude that a direct exposure of the brain to excess insulin results in a down-regulation of the brain insulin receptors.
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