182 results on '"Keith R Martin"'
Search Results
2. Survey of perspectives of people with inherited retinal diseases on ocular gene therapy in Australia
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Heather G. Mack, Alexis Ceecee Britten-Jones, Myra B. McGuinness, Fred K. Chen, John R. Grigg, Robyn V. Jamieson, Thomas L. Edwards, John De Roach, Fleur O’Hare, Keith R. Martin, and Lauren N. Ayton
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Genetics ,Molecular Medicine ,Molecular Biology - Abstract
Many gene therapies are in development for treating people with inherited retinal diseases (IRD). We hypothesized that potential recipients of gene therapy would have knowledge gaps regarding treatment. We aimed to assess knowledge, attitudes, and perceptions of genetic therapies among potential recipients with IRD, using a novel instrument we designed (Attitudes to Gene Therapy-Eye (AGT-Eye)) and their associations with demographic data, self-reported visual status, and tools assessing quality of life and attitudes toward clinical trials using a community-based cross-sectional survey of Australian adults with IRD. AGT-Eye, overall quality of life EQ-5D-5L, National Eye Institute Visual Functioning Questionnaire (NEI-VFQ-25) and Patient Attitudes to Clinical Trials (PACT-22) instruments were administered. Six hundred and eighty-one people completed the study, 51.7% women of mean age 53.5 years (SD ± 15.8). Most participants (91.6%) indicated they would likely accept gene therapy if it was available to them or family members. However, only 28.3% agreed that they had good knowledge of gene therapy. Most obtained information about gene therapy from the internet (49.3%). Respondents with post-graduate degrees scored highest compared to other educational levels on methods (p p = 0.003) and were more likely to see economic value of treatment (p = 0.043). Knowledge gaps were present regarding methods and outcomes of gene therapy. This survey has shown high level of interest in the IRD community for gene therapies, and highlights areas for improved clinician and patient education.
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- 2022
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3. Tart Cherry Juice Reduces Plasma Triglycerides and CVD Risk Factor, But Does not Affect Indirect Measures of Insulin Resistance, in Overweight and Obese Subjects: A Randomized, Crossover Pilot Study
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Keith R Martin, Jennifer Bopp, and Lacey Burrell
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Geography, Planning and Development ,Management, Monitoring, Policy and Law - Published
- 2022
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4. Intraocular Pressure Spikes Following iStent Inject and the Relationship to Aqueous Outflow in Open Angle Glaucoma
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Jed A Lusthaus, Peter J McCluskey, and Keith R Martin
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Ophthalmology - Published
- 2023
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5. Clinical trials in neuroprotection: special considerations
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Zhichao Wu, Jonathan G. Crowston, and Keith R. Martin
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- 2023
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6. List of contributors
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Hanif Ahmad, Raid G. Alany, Jorge L. Alió, Andrew J. Anderson, Anmol Arora, Augusto Azuara-Blanco, Jorge Alio del Barrio, Christophe Baudouin, Reeda Bou Said, Rupert R.A. Bourne, Fatima Butt, David J. Calkins, Geoffrey Z.P. Chan, Ching-Yu Cheng, Rachel S. Chong, Maria Francesca Cordeiro, Jonathan G. Crowston, Qëndresë Daka, Ramin Daneshvar, Jonathan Denniss, Sundeep Singh Deol, Rebecca Epstein, Monica Ertel, Jonathan M. Fam, Ronald L. Fellman, Ted Garway-Heath, Gus Gazzard, Clare Gilbert, Kevin Gillmann, Ivan Goldberg, Jeffrey L. Goldberg, Sumit Grover, Gregg A. Heatley, Esther Hoffmann M., Alex S. Huang, Zi-Bing Jin, Murray Johnstone, Malik Kahook, L. Jay Katz, Paul L. Kaufman, Pearse A. Keane, Anthony P. Khawaja, Ziad Khoueir, Mitchell Lawlor, Christopher Leung, Boris Malyugin, Steven L. Mansberger, Kaweh Mansouri, Keith R. Martin, Christine E. Martinez, Allison M. McKendrick, André Mermoud, Robert W. Nickells, Kouros Nouri-Mahdavi, Tyler D. Oostra, Joel Palko, Radhika Pooja Patel, Zia S. Pradhan, Ramesh Priyanka, Harsha L. Rao, Reza Razeghinejad, Tony Realini, Robert Ritch, Sylvain Roy, Kerstin Sailer, Facundo G. Sanchez, Ursula Schlötzer-Schrehardt, Joel S. Schuman, Andrew Scott, Leonard Seibold, Anant Sharma, George Spaeth, Clemens A. Strohmaier, Maja Szymanska, Angelo P. Tanna, Dada Tanuj, Ian H. Tapply, Andrew J. Tatham, Carol B. Toris, Konstantinos T. Tsasousis, Ningli Wang, Robert N. Weinreb, Janey L. Wiggs, Yu Jun Wo, Gadi Wollstein, Shen Wu, Zhichao Wu, Chen Xin, Chungkwon Yoo, Cara Capitena Young, and Jingxue Zhang
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- 2023
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7. Dietary Nitrates, Nitrites, and Food Safety: Risks Versus Benefits
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Keith R Martin
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business.industry ,Environmental health ,Geography, Planning and Development ,Medicine ,Management, Monitoring, Policy and Law ,business ,Food safety - Published
- 2021
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8. Evaluating multidisciplinary glaucoma care: visual field progression and loss of sight year analysis in the community vs hospital setting
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Tasneem Z Khatib, Maryam Mushtaq, Keith R Martin, Humma Shahid, Jane Kean, Rupert R A Bourne, Sarah Farrell, Nikou Nassehzadeh-Tabriz, Yusuf Mushtaq, Binita Panchasara, and Hong Kai Lim
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Pediatrics ,medicine.medical_specialty ,genetic structures ,Hospital setting ,Vision Disorders ,MEDLINE ,Glaucoma ,Lower risk ,Article ,03 medical and health sciences ,0302 clinical medicine ,Multidisciplinary approach ,medicine ,Humans ,Intraocular Pressure ,Retrospective Studies ,Shared care ,business.industry ,medicine.disease ,Health services ,Hospitals ,eye diseases ,Visual field ,Ophthalmology ,Cohort ,Optic nerve diseases ,Disease Progression ,030221 ophthalmology & optometry ,Visual Field Tests ,Visual Fields ,business ,030217 neurology & neurosurgery - Abstract
BACKGROUND: A variety of shared care models have been developed, which aim to stratify glaucoma patients according to risk of disease progression. However, there is limited published data on the rate of glaucoma progression in the hospital vs community setting. Here we aimed to compare rates of glaucomatous visual field progression in the Cambridge Community Optometrist Glaucoma Scheme (COGS) and Addenbrooke's Hospital Glaucoma Clinic (AGC). METHODS: A retrospective comparative cohort review was performed. Patients with five or more visual field tests were included. Zeiss Forum software was used to calculate the MD progression rate (dB/year). Loss of sight years (LSY) were also calculated for both COGS and AGC. RESULTS: Overall, 8465 visual field tests from 854 patients were reviewed. In all, 362 eyes from the AGC group and 210 eyes from COGS were included. The MD deterioration rate was significantly lower in the COGS patients compared with the AGC group (-0.1 vs -0.3 dB/year; p
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- 2021
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9. Effectively Managing the Co-ingestion of Dietary Supplements and Prescription Drugs
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Richard J. Bloomer, Keith R Martin, and Jacquelyn C. Pence
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medicine.medical_specialty ,business.industry ,Geography, Planning and Development ,Medicine ,Ingestion ,Management, Monitoring, Policy and Law ,Medical prescription ,business ,Intensive care medicine - Published
- 2021
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10. Beyond Nutrition Recommendations: What Healthcare Professionals Should Know about Dietary Supplements to Best Serve Their Patients
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Keith R Martin, Jacquelyn C. Pence, and Richard J. Bloomer
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medicine.medical_specialty ,Health professionals ,business.industry ,Dietary supplement ,medicine.disease ,Malnutrition ,Clinical research ,Nutraceutical ,Family medicine ,medicine ,Whole food ,Medical prescription ,business ,Adverse effect - Abstract
Although whole food nutrition will likely influence physical health more than any other lifestyle component besides exercise, the use of dietary supplements among men and women continues to be high. Due to this fact, it is imperative that healthcare professionals understand how supplements may impact overall health and wellness of their patients. With the majority of adults taking some form of dietary supplements and many concomitantly taking prescription medications, healthcare providers should be conscientious of adverse effects and interactions that may occur between dietary supplements and prescription drugs. As many consumers are misled by false marketing, healthcare providers should encourage them to be wary of exaggerated claims and direct them to products that are scientifically supported and safe. Continuing education for healthcare providers on dietary supplements is crucial, with new dietary supplement products constantly reaching the markets, in addition to new findings being made through clinical research and case studies. While some dietary supplements provide no meaningful benefit, many dietary supplements have been identified that can be used to ameliorate nutritional deficiencies and reduce the risk of some common health conditions. Others can serve to improve mental and physical performance, while truly enhancing health. This article presents relevant information on dietary supplements that will be useful to the healthcare professional.
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- 2021
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11. Survey of perspectives of people with inherited retinal diseases on ocular gene therapy in Australia
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Heather G, Mack, Alexis Ceecee, Britten-Jones, Myra B, McGuinness, Fred K, Chen, John R, Grigg, Robyn V, Jamieson, Thomas L, Edwards, John, De Roach, Fleur, O'Hare, Keith R, Martin, and Lauren N, Ayton
- Abstract
Many gene therapies are in development for treating people with inherited retinal diseases (IRD). We hypothesized that potential recipients of gene therapy would have knowledge gaps regarding treatment. We aimed to assess knowledge, attitudes, and perceptions of genetic therapies among potential recipients with IRD, using a novel instrument we designed (Attitudes to Gene Therapy-Eye (AGT-Eye)) and their associations with demographic data, self-reported visual status, and tools assessing quality of life and attitudes toward clinical trials using a community-based cross-sectional survey of Australian adults with IRD. AGT-Eye, overall quality of life EQ-5D-5L, National Eye Institute Visual Functioning Questionnaire (NEI-VFQ-25) and Patient Attitudes to Clinical Trials (PACT-22) instruments were administered. Six hundred and eighty-one people completed the study, 51.7% women of mean age 53.5 years (SD ± 15.8). Most participants (91.6%) indicated they would likely accept gene therapy if it was available to them or family members. However, only 28.3% agreed that they had good knowledge of gene therapy. Most obtained information about gene therapy from the internet (49.3%). Respondents with post-graduate degrees scored highest compared to other educational levels on methods (p 0.001) and outcomes (p = 0.003) and were more likely to see economic value of treatment (p = 0.043). Knowledge gaps were present regarding methods and outcomes of gene therapy. This survey has shown high level of interest in the IRD community for gene therapies, and highlights areas for improved clinician and patient education.
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- 2022
12. Improvement in inner retinal function in glaucoma with nicotinamide (vitamin <scp>B3</scp> ) supplementation: A crossover randomized clinical trial
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Jonathan G Crowston, Xavier Hadoux, Peter van Wijngaarden, Robert J Casson, Michael Coote, Ian A. Trounce, Jessica Tang, Myra B McGuinness, Peter A. Williams, Flora Hui, and Keith R Martin
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Vitamin ,Niacinamide ,0301 basic medicine ,medicine.medical_specialty ,Intraocular pressure ,Open angle glaucoma ,Glaucoma ,Placebo ,Retinal ganglion ,Retina ,law.invention ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Randomized controlled trial ,law ,Ophthalmology ,Electroretinography ,medicine ,Humans ,medicine.diagnostic_test ,Nicotinamide ,business.industry ,medicine.disease ,Clinical trial ,030104 developmental biology ,chemistry ,Dietary Supplements ,030221 ophthalmology & optometry ,business ,Glaucoma, Open-Angle ,Photic Stimulation - Abstract
Importance: Retinal ganglion cells endure significant metabolic stress with ageing and glaucoma-related stressors. Injured cells require increased energy for repair but maintain capacity to recover function despite periods of functional loss. Nicotinamide, a precursor of redox co-factor and metabolite, NAD + , is low in serum of patients with primary open-angle glaucoma and its supplementation provides robust protection of retinal ganglion cells by targeting mitochondrial health in glaucoma models. However, the potential of nicotinamide to improve retinal ganglion cell function in humans with glaucoma is yet unknown. Objective: To determine whether nicotinamide supplementation taken in conjunction with conventional IOP-lowering therapy leads to early improvement in retinal ganglion cell function in people with glaucoma. Design: Crossover, double-masked, randomized clinical trial conducted between October 2017 to January 2019. Setting: Study participants recruited from two tertiary care centers in Melbourne, Australia. Participants: Adults diagnosed and treated for primary glaucoma. Ninety-four participants assessed for study eligibility. Intervention: Participants randomized to first receive oral placebo or nicotinamide and reviewed six-weekly. Accelerated dosing method utilized; participants commenced 6-week course of 1.5 grams/day followed by 6 weeks of 3.0 grams/day. After 12 weeks, participants crossed over to other intervention for 12 weeks without washout. At each visit, visual function measured using full-field flash electroretinography and white-on-white perimetry. Main outcome measures: Primary endpoint was change in inner retinal function determined a-priori as change in photopic negative response (PhNR) parameters: saturated PhNR amplitude (Vmax), ratio of PhNR/b-wave amplitude (Vmax ratio). Results: Fifty-seven participants (65.5±10.0 years, 39% female) enrolled. PhNR Vmax improved beyond 95% coefficient of repeatability (COR) in 23% of participants following 12 weeks of nicotinamide versus 9% on placebo. Conversely, PhNR Vmax deteriorated in 9% on placebo and 7% on nicotinamide. Overall, Vmax improved by 14.8% [95% CI: 2.8%, 26.9%], (p=0.02) on nicotinamide and 5.2% [-4.2%, 14.6%], (p=0.27) on placebo. Vmax ratio improved on average by 12.6% [5.0%, 20.2%], (p=0.002) following nicotinamide and 3.6% [-3.4%, 10.5%], (p=0.30) on placebo. A concomitant trend for improved visual field mean deviation was observed with 27% improving ≥1dB on nicotinamide and fewer deteriorating ≥1dB (4%) compared to placebo (p=0.02). Moderate correlation was observed between PhNR and visual field change with treatment. Participants demonstrated excellent treatment adherence rates (>94%) and nicotinamide was well tolerated with minimal side effects. Conclusions and Relevance: Nicotinamide supplementation can improve inner retinal function in patients receiving concurrent IOP-lowering glaucoma therapy. Further studies are underway to elucidate the effects of long-term nicotinamide supplementation on glaucoma progression.
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- 2020
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13. Plasma Nitrate and Nitrite as Biological Indicators of Health and Disease in Nutritional Studies
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Keith R. Martin and Richard J. Bloomer
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- 2022
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14. RNA-targeting strategies as a platform for ocular gene therapy
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Satheesh Kumar, Lewis E. Fry, Jiang-Hui Wang, Keith R. Martin, Alex W. Hewitt, Fred K. Chen, and Guei-Sheung Liu
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Ophthalmology ,Sensory Systems - Abstract
Genetic medicine is offering hope as new therapies are emerging for many previously untreatable diseases. The eye is at the forefront of these advances, as exemplified by the approval of Luxturna® by the United States Food and Drug Administration (US FDA) in 2017 for the treatment of one form of Leber Congenital Amaurosis (LCA), an inherited blindness. Luxturna® was also the first in vivo human gene therapy to gain US FDA approval. Numerous gene therapy clinical trials are ongoing for other eye diseases, and novel delivery systems, discovery of new drug targets and emerging technologies are currently driving the field forward. Targeting RNA, in particular, is an attractive therapeutic strategy for genetic disease that may have safety advantages over alternative approaches by avoiding permanent changes in the genome. In this regard, antisense oligonucleotides (ASO) and RNA interference (RNAi) are the currently popular strategies for developing RNA-targeted therapeutics. Enthusiasm has been further fuelled by the emergence of clustered regularly interspersed short palindromic repeats (CRISPR)-CRISPR associated (Cas) systems that allow targeted manipulation of nucleic acids. RNA-targeting CRISPR-Cas systems now provide a novel way to develop RNA-targeted therapeutics and may provide superior efficiency and specificity to existing technologies. In addition, RNA base editing technologies using CRISPR-Cas and other modalities also enable precise alteration of single nucleotides. In this review, we showcase advances made by RNA-targeting systems for ocular disease, discuss applications of ASO and RNAi technologies, highlight emerging CRISPR-Cas systems and consider the implications of RNA-targeting therapeutics in the development of future drugs to treat eye disease.
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- 2023
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15. Nitrate and Human Health
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Keith R Martin and Richard J. Bloomer
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Human health ,chemistry.chemical_compound ,Nitrate ,chemistry ,Environmental chemistry ,Environmental science - Published
- 2021
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16. Comparative analysis of loop-mediated isothermal amplification (LAMP)-based assays for rapid detection of SARS-CoV-2 genes
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Jiang-Hui Wang, Raymond C.B. Wong, Daniel Urrutia-Cabrera, Alex W. Hewitt, Jianxiong Chan, Sandy S.C. Hung, Thomas L Edwards, Roxanne Hsiang-Chi Liou, Keith R Martin, Patrick Kwan, Martin, Keith [0000-0002-9347-3661], and Apollo - University of Cambridge Repository
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Adult ,Male ,Coronavirus disease 2019 (COVID-19) ,Science ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,viruses ,Loop-mediated isothermal amplification ,Computational biology ,Rapid detection ,Article ,False positive paradox ,Humans ,Diagnostic laboratory ,skin and connective tissue diseases ,Saliva ,Gene ,Multidisciplinary ,Chemistry ,SARS-CoV-2 ,Biological techniques ,fungi ,COVID-19 ,Gold standard (test) ,Molecular Diagnostic Techniques ,Color changes ,COVID-19 Nucleic Acid Testing ,Medicine ,Female ,Microbiology techniques ,Nucleic Acid Amplification Techniques - Abstract
The COVID-19 pandemic caused by SARS-CoV-2 has infected millions worldwide, therefore there is an urgent need to increase our diagnostic capacity to identify infected cases. Although RT-qPCR remains the gold standard for SARS-CoV-2 detection, this method requires specialised equipment in a diagnostic laboratory and has a long turn-around time to process the samples. To address this, several groups have recently reported the development of loop-mediated isothermal amplification (LAMP) as a simple, low cost and rapid method for SARS-CoV-2 detection. Herein we present a comparative analysis of three LAMP-based assays that target different regions of the SARS-CoV-2: ORF1ab RdRP, ORF1ab nsp3 and Gene N. We perform a detailed assessment of their sensitivity, kinetics and false positive rates for SARS-CoV-2 diagnostics in LAMP or RT-LAMP reactions, using colorimetric or fluorescent detection. Our results independently validate that all three assays can detect SARS-CoV-2 in 30 min, with robust accuracy at detecting as little as 1000 RNA copies and the results can be visualised simply by color changes. Incorporation of RT-LAMP with fluorescent detection further increases the detection sensitivity to as little as 100 RNA copies. We also note the shortcomings of some LAMP-based assays, including variable results with shorter reaction time or lower load of SARS-CoV-2, and false positive results in some experimental conditions and clinical saliva samples. Overall for RT-LAMP detection, the ORF1ab RdRP and ORF1ab nsp3 assays have faster kinetics for detection but varying degrees of false positives detection, whereas the Gene N assay exhibits no false positives in 30 min reaction time, which highlights the importance of optimal primer design to minimise false-positives in RT-LAMP. This study provides validation of the performance of LAMP-based assays as a rapid, highly sensitive detection method for SARS-CoV-2, which have important implications in development of point-of-care diagnostics for SARS-CoV-2.
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- 2021
17. Impact of AmaTea® Max on physiological measures and gaming performance in active gamers: A placebo-controlled, double-blind, randomized study
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Richard J, Bloomer, Keith R, Martin, and Jacquelyn C, Pence
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The activity of "gaming" has increased greatly in popularity in recent years, with many gamers using nutritional supplements to aid mood and gaming performance. We evaluated the impact of AmaTeaSubjects reported to the lab on three occasions, separated by approximately 1 week. On each day, they had baseline measurements taken and then played the game Fortnite for four 1-h periods. Measures of cognitive performance, gaming performance, heart rate and blood pressure (BP), and blood cortisol were measured before and at selected times following gameplay.Neither caffeine nor AmaTeaAmaTeaActive gamers who seek to use a dietary supplement for purposes of gaming performance may benefit slightly from ingestion of AmaTea
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- 2021
18. Hemoglobin Video Imaging Detects Differences in Aqueous Outflow Between Eyes With and Without Glaucoma During the Water Drinking Test
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Jed A. Lusthaus, Paul A.R. Meyer, Peter J. McCluskey, and Keith R. Martin
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Ophthalmology ,Hemoglobins ,Trabecular Meshwork ,Drinking ,Humans ,Water ,Glaucoma ,Prospective Studies ,Glaucoma, Open-Angle ,Intraocular Pressure - Abstract
Hemoglobin video imaging (HVI) demonstrates increased aqueous outflow (AO) in response to the water drinking test (WDT) in patients with and without glaucoma. In glaucomatous eyes, increased AO was not sustained, and characteristic flow patterns were seen.To observe how variations in intraocular pressure (IOP) correlate with the flow of aqueous in episcleral veins.Prospective observational cohort study.The WDT increased AO into the episcleral venous system in 30 eyes recruited from Sydney Eye Hospital. A comparison was made between glaucomatous (n=20) and nonglaucomatous eyes (n=10).Each patient had baseline IOP and HVI before drinking 10 mL/kg body weight of water. IOP and HVI were then repeated every 15 minutes for 1 hour. Aqueous column cross-sectional area (AqCA) of the most prominent nasal and temporal aqueous veins was used to semi-quantify conventional AO.Change in IOP and AqCA from baseline during the WDT. Aqueous flow characteristics were also observed.Peak IOP elevation above baseline was significantly higher in the glaucoma group, with an average IOP rise of 39.7% on 1.6 1.1 medications, compared with 22.9% in the control group ( P =0.04). AqCA significantly increased for glaucomatous and nonglaucomatous eyes in response to water ingestion ( P0.05). AqCA fell by 50% in glaucomatous eyes ( P =0.003) and 33% in nonglaucomatous eyes ( P =0.08) at study completion compared with the peak measurement. IOP remained30% elevated in 8 glaucomatous eyes (40%) after 60 minutes and no control eyes. Variations in qualitative aqueous flow patterns were observed in glaucomatous eyes but not in controls.AO volume, estimated by AqCA, increases in response to IOP elevation induced by an ingested water bolus in patients with and without glaucoma. The increase in aqueous drainage was not sustained in glaucomatous eyes and may have led to incomplete recovery of IOP. Using HVI in combination with the WDT may assist with clinical decision-making and facilitate the monitoring of responses to treatment.
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- 2021
19. Neuroprotection in Glaucoma: Towards Clinical Trials and Precision Medicine
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Tasneem Z Khatib and Keith R Martin
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medicine.medical_specialty ,Intraocular pressure ,genetic structures ,MEDLINE ,Glaucoma ,Cochrane Library ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,0302 clinical medicine ,Animals ,Humans ,Medicine ,Precision Medicine ,Intensive care medicine ,Antihypertensive Agents ,Intraocular Pressure ,Modalities ,business.industry ,Translational medicine ,Precision medicine ,medicine.disease ,Neuroprotection ,eye diseases ,Sensory Systems ,Clinical trial ,Ophthalmology ,030221 ophthalmology & optometry ,business ,030217 neurology & neurosurgery - Abstract
Purpose: The eye is currently at the forefront of translational medicine and therapeutics. However, despite advances in technology, primary open-angle glaucoma remains the leading cause of irreversible blindness worldwide. Traditional intraocular pressure (IOP)-lowering therapies are often not sufficient to prevent progression to blindness, even in patients with access to high-quality healthcare. Neuroprotection strategies, which aim to boost the ability of target cells to withstand a pathological insult, have shown significant promise in animal models but none have shown clinically relevant efficacy in human clinical trials to date. We sought to evaluate the current status of neuroprotection clinical trials for glaucoma and identify limitations which have prevented translation of new glaucoma therapies to date.Methods: Literature searches identified English language references. Sources included MEDLINE, EMBASE, the Cochrane Library and Web of Science databases; reference lists of retrieved studies; and internet pages of relevant organisations, meetings and conference proceedings, and clinical trial registries.Results: We discuss six key neuroprotective strategies for glaucoma that have reached the clinical trial stage. Delivery of neurotrophic factors through gene therapy is also progressing towards glaucoma clinical trials. Refinements in trial design and the use of new modalities to define structural and functional endpoints may improve our assessment of disease activity and treatment efficacy. Advances in our understanding of compartmentalised glaucomatous degeneration and continued progress in the molecular profiling of glaucoma patients will enable us to predict individual risk and tailor treatment.Conclusion: New approaches to future glaucoma neuroprotection trials could improve the prospects for new glaucoma therapies. Glaucoma treatment tailored according to an individual's unique risk profile may become increasingly common in the future.
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- 2019
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20. Selective laser trabeculoplasty versus topical medication as initial glaucoma treatment: the glaucoma initial treatment study randomised clinical trial
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Jing Xie, Andrew White, Sutha Sanmugasundram, Anthony P Wells, Ryan Eyn Kidd Man, Eva K Fenwick, Jonathan G Crowston, Robert J Casson, Alfred Tau Liang Gan, Rachel McIntosh, Ivan Goldberg, Mark J Walland, Marios Constantinou, Jonathan Jackson, Paul R. Healey, Konrad Pesudovs, Ecosse L. Lamoureux, Eric A. Finkelstein, Keith R Martin, and Ghee Soon Ang
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Male ,Intraocular pressure ,medicine.medical_specialty ,genetic structures ,medicine.medical_treatment ,Glaucoma ,Timolol ,Trabeculectomy ,Lasers, Solid-State ,law.invention ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,0302 clinical medicine ,Randomized controlled trial ,Quality of life ,law ,Internal medicine ,medicine ,Humans ,Antihypertensive Agents ,Intraocular Pressure ,business.industry ,Middle Aged ,medicine.disease ,Sensory Systems ,Topical medication ,Clinical trial ,Ophthalmology ,Treatment Outcome ,Quality of Life ,030221 ophthalmology & optometry ,Female ,Laser Therapy ,Ophthalmic Solutions ,business ,030217 neurology & neurosurgery ,medicine.drug - Abstract
Background/AimsTo determine if selective laser trabeculoplasty (SLT) is superior to topical medication as a first-line treatment for glaucoma on quality of life (QoL) and clinical outcomes.MethodsIn this international, longitudinal, multisite randomised controlled trial, treatment naïve mild-to-moderate primary open angle or exfoliation glaucoma patients were randomised 1:1 to SLT or topical medication. Glaucoma-specific QoL (primary outcome) was measured using the Glaucoma Outcomes Assessment Tool (GOAT; 342 items, 12 domains). Secondary outcomes included rate of successful intraocular pressure (IOP) reduction (>25% reduction from baseline) and presence of ocular surface disease including conjunctival hyperaemia and eyelid erythema. Our intention-to-treat analysis was performed at months 12 and 24.ResultsOf 167 enrolled patients, 83 and 84 were randomised to SLT and topical medication, respectively; and 145 (n=75 SLT, n=70 medication) completed 24-month follow-up. While both treatment arms achieved significant within-group gains in GOAT outcomes at both endpoints, SLT patients reported a greater between-group improvement in ‘social well-being’ compared with medication patients (mean±SE=0.28±0.13; p=0.034) at 24 months. At month 24, the rate of successful IOP reduction was 18.6% (95% CI 3.0% to 34.3%, p=0.022) higher (absolute difference) in the medication compared with SLT group. More individuals in the medication group had conjunctival hyperaemia and eyelid erythema compared with SLT at 24 months.ConclusionOverall, we did not find evidence that SLT was superior to medication in improving glaucoma-specific QoL. While we found superior IOP reduction in the medication arm, eyelid erythema and conjunctival hyperaemia were more prevalent in these patients compared with the SLT group.Trial registrationACTRN12611000720910.
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- 2019
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21. Hemoglobin Video Imaging Provides Novel In Vivo High-Resolution Imaging and Quantification of Human Aqueous Outflow in Patients with Glaucoma
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Tasneem Z Khatib, Yusuf Mushtaq, Keith R Martin, Ilya Manyakin, Paul A R Meyer, and Jed Lusthaus
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Adult ,Male ,SLT, selective laser trabeculoplasty ,Intraocular pressure ,medicine.medical_specialty ,CSA, cross-sectional area ,MIGS, minimally invasive glaucoma surgery ,genetic structures ,Minimally invasive glaucoma surgery ,Pulsatile flow ,Glaucoma ,Trabeculectomy ,01 natural sciences ,Article ,Aqueous Humor ,Hemoglobins ,03 medical and health sciences ,0302 clinical medicine ,HVI, hemoglobin video imaging ,In vivo ,Ophthalmology ,medicine ,Humans ,Prospective Studies ,0101 mathematics ,Vein ,Intraocular Pressure ,business.industry ,010102 general mathematics ,General Medicine ,Middle Aged ,medicine.disease ,IOP, intraocular pressure ,eye diseases ,MD, mean deviation ,medicine.anatomical_structure ,030221 ophthalmology & optometry ,Female ,Laser Therapy ,sense organs ,Apraclonidine ,Hemoglobin ,Visual Fields ,business ,Biomarkers ,Glaucoma, Open-Angle ,medicine.drug - Abstract
Purpose Noninvasive, detailed measurement of the dynamics of human aqueous outflow is difficult to achieve with currently available clinical tools. We used hemoglobin video imaging (HVI) to develop a technique to image and quantify human aqueous outflow noninvasively and in real time. Design A prospective observational study to describe characteristics of aqueous veins and a pilot prospective interventional feasibility study to develop quantification parameters. Participants Patients were recruited from the Cambridge University Hospitals NHS Foundation Trust Glaucoma clinic. The observational study included 30 eyes, and the pilot interventional feasibility study was performed on 8 eyes undergoing selective laser trabeculoplasty (SLT). Our SLT protocol also included the installation of pilocarpine and apraclonidine eye drops. Methods Participants underwent HVI alongside their usual clinic visit. Main Outcome Measures The change in cross-sectional area (CSA) of the aqueous column within episcleral veins was correlated with intraocular pressure (IOP) reduction and change in visual field mean deviation (MD) before and after intervention. Fluctuations in contrast and pixel intensity of red blood cells in an aqueous vein were calculated to compare the flow rate before and after intervention using autocorrelation analysis. Results Hemoglobin video imaging enables the direct observation of aqueous flow into the vascular system. Aqueous is seen to centralize within a laminar venous column. Flow is pulsatile, and fluctuations of flow through globe pressure or compression of the aqueous vein are observed. There was a significant increase in the aqueous column after the administration of our SLT protocol (n = 13; P < 0.05). This correlated with the degree of IOP reduction (n = 13; Pearson’s correlation coefficient 0.7; P = 0.007) and the improvement in MD observed postintervention (n = 8; Pearson’s correlation coefficient 0.75; P = 0.03). Autocorrelation analysis demonstrated a faster rate of decay in an aqueous vein after intervention, indicating an increase in flow rate. Conclusions Hemoglobin video imaging can be incorporated into a routine clinic slit-lamp examination to allow a detailed assessment and quantification of aqueous outflow in real time. It has the potential to be used to help target therapeutic interventions to improve aqueous outflow and further advance our understanding of aqueous outflow dysregulation in the pathogenesis of glaucoma.
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- 2019
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22. Are Patient Self-Reported Outcome Measures Sensitive Enough to Be Used as End Points in Clinical Trials?
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Lee Jones, David F. Garway-Heath, Augusto Azuara-Blanco, David P. Crabb, Catey Bunce, Gerassimos Lascaratos, Francesca Amalfitano, Nitin Anand, Rupert R. Bourne, David C. Broadway, Ian A. Cunliffe, Jeremy P. Diamond, Scott G. Fraser, Tuan A. Ho, Keith R. Martin, Andrew I. McNaught, Anil Negi, Krishna Patel, Richard A. Russell, Ameet Shah, Paul G. Spry, Katsuyoshi Suzuki, Edward T. White, Richard P. Wormald, Wen Xing, and Thierry G. Zeyen
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medicine.medical_specialty ,genetic structures ,Visual analogue scale ,Glaucoma ,Placebo ,law.invention ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Randomized controlled trial ,law ,Internal medicine ,Medicine ,Latanoprost ,030304 developmental biology ,0303 health sciences ,business.industry ,medicine.disease ,female genital diseases and pregnancy complications ,eye diseases ,Clinical trial ,Ophthalmology ,Prostaglandin analog ,chemistry ,030221 ophthalmology & optometry ,Secondary Outcome Measure ,sense organs ,business - Abstract
Purpose The United Kingdom Glaucoma Treatment Study (UKGTS) demonstrated the effectiveness of an intraocular pressure-lowering drug in patients with glaucoma using visual field progression as a primary outcome. The present study tested the hypothesis that responses on patient-reported outcome measures (PROMs; secondary outcome measure) differ between patients receiving a topical prostaglandin analog (latanoprost) or placebo eye drops in UKGTS. Design Multicenter, randomized, triple-masked, placebo-controlled trial. Participants Newly diagnosed glaucoma patients in the UKGTS with baseline and exit PROMs (n = 182 and n = 168 patients from the treatment and placebo groups, respectively). Methods In the UKGTS (trial registration number, ISRCTN96423140), patients with open-angle glaucoma were allocated to receive latanoprost (treatment) or placebo; the observation period was 24 months. Patients completed general health PROMs (European Quality of Life in 5 Dimensions [EQ-5D] and 36-item Short Form [SF-36]) and PROMs specific to glaucoma (15-item Glaucoma Quality of Life [GQL-15] and 9-item Glaucoma Activity Limitation [GAL-9]) at baseline and exit from the trial. Percentage changes between measurement on PROMs were calculated for each patient and compared between treatment arms. In addition, differences between stable patients (n = 272) and those with glaucomatous progression (n = 78), as determined by visual field change (primary outcome), were assessed. Main Outcome Measure PROMs on health-related and vision-related quality of life. Results Average percentage change on PROMs was similar for patients in both arms of the trial, with no statistically significant differences between treatment and placebo groups (EQ-5D, P = 0.98; EQ-5D visual analog scale, P = 0.88; SF-36, P = 0.94, GQL-15, P = 0.66; GAL-9, P = 0.87). There were statistically significant differences between stable and progressing patients on glaucoma-specific PROMs (GQL-15, P = 0.02; GAL-9, P = 0.02), but not on general health PROMs (EQ-5D, P = 0.62; EQ-5D visual analog scale, P = 0.23; SF-36, P = 0.65). Conclusions Average change in PROMs on health-related and vision-related quality of life was similar for the treatment and placebo groups in the UKGTS. The PROMs used may not be sensitive enough to function as primary end points in clinical trials when participants have newly diagnosed early-stage glaucoma.
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- 2019
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23. Perspectives of people with inherited retinal diseases on ocular gene therapy in Australia: protocol for a national survey
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Fred K Chen, Alex W Hewitt, Alan Ma, John Grigg, Keith R Martin, Robyn Jamieson, Heather G Mack, Fleur O’Hare, David Mackey, John De Roach, Alexis Ceecee Britten-Jones, Myra McGuinness, Nicole Tindill, Lauren Ayton, Anai Gonzalez Cordero, Thomas L Edwards, Gladys Ho, Michael Hogden, Anthony Kwan, Tina Lamey, Terri McLaren, Benjamin Nash, Jon Ruddle, Matthew Simunovic, Ingrid Sinnerbrink, Deepa Ajay Taranath, Jen Thompson, and Jaclyn White
- Subjects
Adult ,medicine.medical_specialty ,Genetic enhancement ,Leber Congenital Amaurosis ,Disease ,03 medical and health sciences ,0302 clinical medicine ,Quality of life ,Retinal Diseases ,Retinitis pigmentosa ,Medicine ,Humans ,genetics ,medical retina ,030304 developmental biology ,Protocol (science) ,0303 health sciences ,business.industry ,vitreoretinal ,Australia ,General Medicine ,Genetic Therapy ,medicine.disease ,Clinical trial ,Ophthalmology ,Clinical research ,Family medicine ,Cohort ,030221 ophthalmology & optometry ,Quality of Life ,business - Abstract
IntroductionVoretigene neparvovec-rzyl (Luxturna) was approved by the Australian Therapeutic Goods Administration on 4 August 2020 for the treatment of biallelic mutations in the RPE65 gene, a rare cause of congenital and adult-onset retinal dystrophy (predominantly Leber congenital amaurosis). Previous studies have shown that individuals who might participate in gene therapy trials overestimate clinical effect and underestimate risks. However, little is known about the perspectives of patients who may be offered approved gene therapy treatment for ocular conditions (as distinct from participating in clinical trials of gene therapy). The main objective of this study is to develop a tool to assess knowledge, attitudes and perceptions of approved and future genetic therapies among potential recipients of ocular gene therapy. In addition, we aim to assess the quality of life, attitudes towards clinical trials and vision-related quality of life among this cohort.Methods and analysisA new ‘Attitudes to Gene Therapy for the Eye’ tool will be developed following consultation with people with inherited retinal disease (IRD) and content matter experts. Australians with IRD or their guardians will be asked to complete an internet-based survey comprising existing quality of life and visual function instruments and items for the newly proposed tool. We expect to recruit 500 survey participants from patient support groups, the practices of Australian ophthalmologists who are specialists in IRD and Australian ophthalmic research institutions. Launch is anticipated early 2021. Responses will be analysed using item response theory methodology.Ethics and disseminationThis study has received ethics approval from the University of Melbourne (#2057534). The results of the study will be published in a peer-reviewed journal and will be presented at relevant conferences. Organisations involved in recruitment, and the Patient Engagement Advisory committee will assist the research team with dissemination of the study outcomes.
- Published
- 2021
24. Receptor-ligand supplementation via a self-cleaving 2A peptide–based gene therapy promotes CNS axonal transport with functional recovery
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Andrew Osborne, Peter S. Widdowson, Ilya Manyakin, Katie Hall, Tasneem Z Khatib, Zara Ali, Keith R Martin, Robert Watt, Wanyi Jia, Sujeong Yang, Khatib, Tasneem Z [0000-0001-6576-451X], Ali, Zara [0000-0001-8442-1387], Hall, Katie [0000-0002-5612-5369], and Apollo - University of Cambridge Repository
- Subjects
genetic structures ,Genetic enhancement ,Receptor expression ,Tropomyosin receptor kinase B ,Ligands ,Axonal Transport ,03 medical and health sciences ,0302 clinical medicine ,Neurotrophic factors ,medicine ,Receptor ,Research Articles ,030304 developmental biology ,Neurons ,0303 health sciences ,Multidisciplinary ,Chemistry ,SciAdv r-articles ,Genetic Therapy ,medicine.disease ,Ligand (biochemistry) ,eye diseases ,Cell biology ,Dietary Supplements ,Axoplasmic transport ,Tauopathy ,030217 neurology & neurosurgery ,Research Article ,Neuroscience - Abstract
From vision impairment to memory loss, neurotrophin and receptor supplementation using gene therapy promotes functional recovery., Gene replacement approaches are leading to a revolution in the treatment of previously debilitating monogenic neurological conditions. However, the application of gene therapy to complex polygenic conditions has been limited. Down-regulation or dysfunction of receptor expression in the disease state or in the presence of excess ligand has been shown to compromise therapeutic efficacy. Here, we offer evidence that combined overexpression of both brain-derived neurotrophic factor and its receptor, tropomyosin receptor kinase B, is more effective in stimulating axonal transport than either receptor administration or ligand administration alone. We also show efficacy in experimental glaucoma and humanized tauopathy models. Simultaneous administration of a ligand and its receptor by a single gene therapy vector overcomes several problems relating to ligand deficiency and receptor down-regulation that may be relevant to multiple neurodegenerative diseases. This approach shows promise as a strategy to target intrinsic mechanisms to improve neuronal function and facilitate repair.
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- 2021
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25. Humoral immune responses to AAV gene therapy in the ocular compartment
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Michael Whitehead, Patrick Yu-Wai-Man, Andrew Osborne, and Keith R Martin
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0106 biological sciences ,0303 health sciences ,viruses ,Immunogenicity ,Genetic enhancement ,Genetic Vectors ,Genetic Therapy ,Biology ,Dependovirus ,010603 evolutionary biology ,01 natural sciences ,General Biochemistry, Genetics and Molecular Biology ,Virus ,Viral vector ,Immunity, Humoral ,03 medical and health sciences ,Immune system ,Immunity ,Immunology ,biology.protein ,Humans ,Vector (molecular biology) ,Antibody ,General Agricultural and Biological Sciences ,030304 developmental biology - Abstract
Viral vectors can be utilised to deliver therapeutic genes to diseased cells. Adeno-associated virus (AAV) is a commonly used viral vector that is favoured for its ability to infect a wide range of tissues whilst displaying limited toxicity and immunogenicity. Most humans harbour anti-AAV neutralising antibodies (NAbs) due to subclinical infections by wild-type virus during infancy and these pre-existing NAbs can limit the efficiency of gene transfer depending on the target cell type, route of administration and choice of serotype. Vector administration can also result in de novo NAb synthesis that could limit the opportunity for repeated gene transfer to diseased sites. A number of strategies have been described in preclinical models that could circumvent NAb responses in humans, however, the successful translation of these innovations into the clinical arena has been limited. Here, we provide a comprehensive review of the humoral immune response to AAV gene therapy in the ocular compartment. We cover basic AAV biology and clinical application, the role of pre-existing and induced NAbs, and possible approaches to overcoming antibody responses. We conclude with a framework for a comprehensive strategy for circumventing humoral immune responses to AAV in the future.
- Published
- 2021
26. How to Reduce Error in Optic Nerve Head Examination
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Craig Ross, Michael Coote, Keith R Martin, and George Kong
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medicine.medical_specialty ,genetic structures ,business.industry ,Disease progression ,Glaucoma ,medicine.disease ,eye diseases ,Objective assessment ,nervous system ,Cup-disc ratio ,Head examination ,Ophthalmology ,Neuroretinal rim ,medicine ,Optic nerve ,Head (vessel) ,sense organs ,business - Abstract
Diagnosis of glaucoma requires more than the optic nerve head (ONH) evaluation findings alone, but ONH assessment is crucial to detection of glaucoma, assessment of severity, and monitoring for disease progression. Objective assessment of the ONH must be done independent of other clinical features. This chapter explores the process of examining the disc for glaucoma, where errors may occur, and strategies to avoid them.
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- 2021
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27. Aqueous outflow imaging techniques and what they tell us about intraocular pressure regulation
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Paul A R Meyer, Tasneem Z Khatib, Peter McCluskey, Jed Lusthaus, Keith R Martin, Lusthaus, Jed A [0000-0002-4111-5408], and Apollo - University of Cambridge Repository
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Aqueous outflow ,Intraocular pressure ,medicine.medical_specialty ,Open angle glaucoma ,genetic structures ,Glaucoma ,Aqueous humor ,Review Article ,Aqueous Humor ,03 medical and health sciences ,Tonometry, Ocular ,0302 clinical medicine ,Imaging Tool ,Trabecular Meshwork ,Ophthalmology ,medicine ,Animals ,Humans ,Intraocular Pressure ,business.industry ,Treatment options ,medicine.disease ,eye diseases ,030221 ophthalmology & optometry ,Imaging technology ,sense organs ,business ,030217 neurology & neurosurgery ,Glaucoma, Open-Angle - Abstract
Recent advances in the medical and surgical management of open-angle glaucoma have increased the number of treatment options available. Several new intraocular pressure (IOP)-lowering treatments target the conventional aqueous outflow (AO) system. However, success rates are variable and outcomes in individual patients are often difficult to predict. Variable treatment responses remain unexplained and highlight deficiencies in our current understanding of AO regulation and IOP homeostasis. Imaging is often relied upon to confirm diagnoses and monitor treatment responses in other ocular and systemic pathologies. As yet no suitable AO imaging tool has been developed to fulfil this role in glaucoma. A variety of imaging techniques have been used to study the AO tracts of humans and animals in ex vivo and in vivo eyes. In this review, results from novel imaging techniques that assess aqueous drainage through the episcleral venous system are considered and we argue these provide new insights into AO regulation. We suggest that the ability to objectively measure AO responses to interventions would be a significant clinical advance, and we have demonstrated that this can be achieved with direct visualisation of aqueous drainage. We predict that the evolution of AO imaging technology will continue to reveal critical components of AO and IOP regulation, and that personalised IOP-lowering treatment in glaucoma care may well become a reality in the near future.
- Published
- 2021
28. Getting Better: Learning, New Tools and Risk Management
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Keith R Martin, Michael Coote, and Zhichao Wu
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genetic structures ,Multimedia ,business.industry ,Computer science ,Deep learning ,computer.software_genre ,eye diseases ,Visualization ,Optic nerve ,sense organs ,Artificial intelligence ,business ,computer ,Risk management - Abstract
Large degree of variations has been reported in the performance of qualified eyecare practitioners as regard optic nerve head evaluation. This chapter describes in brief recent advances such as artificial intelligence (AI) and advances in imaging and visualisation of ONH. Deep learning model of AI has been developed to discriminate optic nerve photographs from those with and without glaucoma. Adaptive optics are being incorporated to OCT imaging system to improve image resolution and quality.
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- 2021
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29. Tart cherry juice consumed daily for 4 weeks does not impair or exacerbate biomarkers of metabolic function in at‑risk overweight and obese subjects: A randomized, crossover pilot study
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Keith R Martin, Jennifer Bopp, and Lacey Burrell
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medicine.medical_specialty ,Metabolic function ,Cherry juice ,business.industry ,Internal medicine ,comic_books ,medicine ,Obese subjects ,Overweight ,medicine.symptom ,business ,comic_books.series - Published
- 2020
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30. Protrudin functions from the endoplasmic reticulum to support axon regeneration in the adult CNS
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Andrea G. Solano, Yunfei Yang, Evan Reid, Robert Watt, Keith R Martin, Veselina Petrova, James R. Tribble, Richard Eva, Craig S Pearson, Peter A. Williams, Jared Ching, Fiona Love, Andrew Osborne, Herbert M. Geller, James W. Fawcett, Petrova, Veselina [0000-0002-5593-0198], Yang, Yunfei [0000-0002-7130-9801], Love, Fiona M. [0000-0002-7805-5234], Reid, Evan [0000-0003-1623-7304], Williams, Pete A. [0000-0001-6194-8397], Martin, Keith R. [0000-0002-9347-3661], Geller, Herbert M. [0000-0002-7048-6144], Eva, Richard [0000-0003-0305-0452], Fawcett, James W. [0000-0002-7990-4568], Apollo - University of Cambridge Repository, Love, Fiona M [0000-0002-7805-5234], Williams, Pete A [0000-0001-6194-8397], Martin, Keith R [0000-0002-9347-3661], Geller, Herbert M [0000-0002-7048-6144], and Fawcett, James W [0000-0002-7990-4568]
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Central Nervous System ,0301 basic medicine ,Integrins ,Vesicular Transport Proteins ,General Physics and Astronomy ,Endoplasmic Reticulum ,38/70 ,Rats, Sprague-Dawley ,Mice ,13/1 ,0302 clinical medicine ,Phosphorylation ,Axon ,14/19 ,lcsh:Science ,Cells, Cultured ,Neurons ,Multidisciplinary ,631/378/87 ,article ,Endoplasmic reticulum localization ,humanities ,3. Good health ,Cell biology ,Neuroprotective Agents ,medicine.anatomical_structure ,Female ,64/60 ,Endosome ,Science ,Central nervous system ,13/106 ,Endosomes ,13/109 ,Biology ,Retina ,General Biochemistry, Genetics and Molecular Biology ,03 medical and health sciences ,Protein Domains ,Cellular neuroscience ,medicine ,Animals ,Humans ,Regeneration and repair in the nervous system ,Growth cone ,14/35 ,631/378/1687 ,Regeneration (biology) ,Endoplasmic reticulum ,General Chemistry ,Axons ,Nerve Regeneration ,Rats ,Mice, Inbred C57BL ,030104 developmental biology ,nervous system ,Optic Nerve Injuries ,Mutation ,13/51 ,14/63 ,lcsh:Q ,030217 neurology & neurosurgery - Abstract
Adult mammalian central nervous system axons have intrinsically poor regenerative capacity, so axonal injury has permanent consequences. One approach to enhancing regeneration is to increase the axonal supply of growth molecules and organelles. We achieved this by expressing the adaptor molecule Protrudin which is normally found at low levels in non-regenerative neurons. Elevated Protrudin expression enabled robust central nervous system regeneration both in vitro in primary cortical neurons and in vivo in the injured adult optic nerve. Protrudin overexpression facilitated the accumulation of endoplasmic reticulum, integrins and Rab11 endosomes in the distal axon, whilst removing Protrudin’s endoplasmic reticulum localization, kinesin-binding or phosphoinositide-binding properties abrogated the regenerative effects. These results demonstrate that Protrudin promotes regeneration by functioning as a scaffold to link axonal organelles, motors and membranes, establishing important roles for these cellular components in mediating regeneration in the adult central nervous system., Increasing the supply of growth machinery to axons is a potential strategy for promoting repair after injury. Here the authors demonstrate that the endoplasmic reticulum adaptor molecule Protrudin provides cellular components that support axonal regeneration in the adult CNS.
- Published
- 2020
31. The Effects of Trabecular Bypass Surgery on Conventional Aqueous Outflow, Visualized by Hemoglobin Video Imaging
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Jed Lusthaus, Keith R Martin, Paul A R Meyer, Tasneem Z Khatib, Martin, Keith [0000-0002-9347-3661], and Apollo - University of Cambridge Repository
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Male ,medicine.medical_specialty ,Intraocular pressure ,genetic structures ,medicine.medical_treatment ,Video Recording ,Glaucoma ,Aqueous Humor ,Cohort Studies ,03 medical and health sciences ,Hemoglobins ,Tonometry, Ocular ,0302 clinical medicine ,Trabecular Meshwork ,Ophthalmology ,medicine ,Humans ,Prospective Studies ,Prospective cohort study ,Glaucoma Drainage Implants ,Intraocular Pressure ,Phacoemulsification ,business.industry ,Blood flow ,Cataract surgery ,Middle Aged ,medicine.disease ,eye diseases ,Sclera ,medicine.anatomical_structure ,Bypass surgery ,Regional Blood Flow ,030221 ophthalmology & optometry ,Female ,Stents ,sense organs ,business ,Conjunctiva ,030217 neurology & neurosurgery ,Blood Flow Velocity ,Glaucoma, Open-Angle - Abstract
PRECIS: Hemoglobin Video Imaging (HVI) provides a noninvasive method to quantify aqueous outflow (AO) perioperatively. Trabecular bypass surgery (TBS) is able to improve, and in some cases re-establish, conventional AO. PURPOSE: The purpose of this study was to use HVI to illustrate and quantify effects of TBS on AO through the episcleral venous system. DESIGN: This is a prospective observational cohort study. PARTICIPANTS: Patients were recruited from Sydney Eye Hospital, Australia. The study included 29 eyes from 25 patients, 15 with glaucoma and 14 normal controls. TBS (iStent Inject) was performed on 14 glaucomatous eyes (9 combined phacoemulsification/TBS and 5 standalone TBS). Cataract surgery alone was performed on the remaining eye from the glaucoma group and 2 eyes from the control group. METHODS: We used HVI, a novel clinic-based tool, to visualize and quantify AO perioperatively during routine follow-up to 6 months. Angiographic blood flow patterns were observed within prominent aqueous veins on the nasal and temporal ocular surface. Aqueous column cross-section area (AqCA) was compared before and after surgery. MAIN OUTCOME MEASURES: AqCA, number of aqueous veins, intraocular pressure (IOP) before and after surgery, and number of IOP-lowering medications. RESULTS: Patients with glaucoma had reduced AqCA compared with normal controls (P=0.00001). TBS increased AqCA in 13 eyes at 1 month (n=14; P
- Published
- 2020
32. Immunochemical analysis of the integrin expression in retinal pigment epithelial cells
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James W. Fawcett, Jessica C. F. Kwok, Tristan G. Heintz, Janosch P. Heller, and Keith R Martin
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Cell type ,biology ,Chemistry ,Integrin ,Retinal ,eye diseases ,Cell biology ,Transplantation ,chemistry.chemical_compound ,Immunochemistry ,biology.protein ,Extracellular ,sense organs ,Cell adhesion ,Immortalised cell line - Abstract
Retinal pigment epithelial (RPE) cells have been used in disease modelling and transplantation studies in retinal diseases. Several types of RPE cells have been trialed, ranging from primary cells and immortalized cell lines to stem cell-derived RPE cells. During aging and in disease, the extracellular environment of the RPE cells changes, interfering with RPE cell adhesion. We hypothesize that this could be a key problem in transplantation studies that have reported lack of adhesion and survival of the transplanted RPE cells. Integrins are essential for the proper function of the RPE, mediating adhesion to Bruch’s membrane, and the binding and subsequent phagocytosis of photoreceptor outer segments. Variability that has been found in clinical trials might be due to the variability of cell types used and their expression profiles of surface molecules. Here, we set out to analyze integrin expression in primary rat RPE cells and in the human cell line ARPE-19 using immunochemistry. We found that both cell types express integrins to varying degrees. After long-term culturing, ARPE-19 cells resemble mature RPE cells, and increase integrin expression. We hence argue that it is important to test the properties of these cells prior to transplantation to avoid failure of adhesion and to facilitate correct function.
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- 2020
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33. Neuronal Reprogramming for Tissue Repair and Neuroregeneration
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Raymond C.B. Wong, Keith R Martin, Thomas L Edwards, Roxanne Hsiang-Chi Liou, Edwards, Thomas L [0000-0003-0238-7416], Martin, Keith R [0000-0002-9347-3661], Wong, Raymond Ching-Bong [0000-0002-8092-9455], Apollo - University of Cambridge Repository, Edwards, Thomas L. [0000-0003-0238-7416], and Martin, Keith R. [0000-0002-9347-3661]
- Subjects
Pluripotent Stem Cells ,retina ,Cellular differentiation ,Neurogenesis ,Review ,Regenerative Medicine ,Regenerative medicine ,Catalysis ,Inorganic Chemistry ,lcsh:Chemistry ,Directed differentiation ,medicine ,Animals ,Humans ,Cellular Reprogramming Techniques ,Physical and Theoretical Chemistry ,Induced pluripotent stem cell ,Molecular Biology ,lcsh:QH301-705.5 ,Spectroscopy ,neuroregeneration ,cell reprogramming ,Organic Chemistry ,Cell Differentiation ,General Medicine ,Cellular Reprogramming ,Computer Science Applications ,medicine.anatomical_structure ,lcsh:Biology (General) ,lcsh:QD1-999 ,Cell Transdifferentiation ,Stem cell ,Neuroscience ,Reprogramming ,Muller glia - Abstract
Stem cell and cell reprogramming technology represent a rapidly growing field in regenerative medicine. A number of novel neural reprogramming methods have been established, using pluripotent stem cells (PSCs) or direct reprogramming, to efficiently derive specific neuronal cell types for therapeutic applications. Both in vitro and in vivo cellular reprogramming provide diverse therapeutic pathways for modeling neurological diseases and injury repair. In particular, the retina has emerged as a promising target for clinical application of regenerative medicine. Herein, we review the potential of neuronal reprogramming to develop regenerative strategy, with a particular focus on treating retinal degenerative diseases and discuss future directions and challenges in the field.
- Published
- 2020
34. Effect of Hot Water Extracts of Maqui Berry on Human Aortic Endothelial Cells Exposed to a Hyperglycemic Environment
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Keith R Martin
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medicine.medical_specialty ,Aorta ,Nutrition and Dietetics ,Endothelium ,Insulin ,medicine.medical_treatment ,Medicine (miscellaneous) ,Inflammation ,Vasodilation ,Dietary Bioactive Components ,medicine.disease_cause ,medicine.disease ,Nitric oxide ,chemistry.chemical_compound ,Endocrinology ,medicine.anatomical_structure ,chemistry ,Diabetes mellitus ,Internal medicine ,medicine.artery ,medicine ,medicine.symptom ,Oxidative stress ,Food Science - Abstract
OBJECTIVES: Impaired endothelial function is associated with many chronic vascular-related diseases including cardiovascular disease, inflammation, and diabetes. The antioxidant-rich Maqui berry (Aristotelia chilensis) has received increasing attention due to a variety of bioactivities including reduction of inflammation, control of blood glucose, and improvement of heart health, e.g., aortic endothelium, but corroborative research is needed. In the present study, we investigated the effects of aqueous Maqui berry extract (MBE) on nitric oxide (NO) production and oxidative stress (ROS) generation in human aortic endothelial cells (HAEC) alone or in a hyperglycemic environment with or without insulin. METHODS: Sterile (0.22 um filtered) MBE was added to endothelial basal medium (5% v/v) alone or containing glucose (final concentration 600 mg/dL; 33.3 mM) and/or insulin (final concentration 100 nM) followed by addition to monolayers and incubation for 24 hours. Monolayers were then assayed for NO production via the Greiss reaction, ROS via the use of DCFH-DA, and viability using MTT. RESULTS: We show that MBE may have increased ROS levels by 1.8-fold (P
- Published
- 2020
35. Acute Ingestion of A Novel Nitrate-Rich Dietary Supplement Significantly Increases Plasma Nitrate/Nitrite in Physically Active Men and Women
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Richard J. Bloomer, Matthew Butawan, Keith R Martin, and Brandon Pigg
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Adult ,Male ,0301 basic medicine ,lcsh:TX341-641 ,Nitric Oxide ,Placebo ,Article ,Nitric oxide ,Young Adult ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Animal science ,Nitrate ,Spinacia oleracea ,nitrate ,Photinia ,Heart rate ,heart rate ,Humans ,Ingestion ,Nutritional Physiological Phenomena ,Nitrite ,Exercise ,Nitrites ,NOx ,Nitrates ,030109 nutrition & dietetics ,Nutrition and Dietetics ,red spinach ,Dose-Response Relationship, Drug ,aronia berry ,blood pressure ,030229 sport sciences ,Blood pressure ,chemistry ,Dietary Supplements ,beetroot ,Female ,Beta vulgaris ,lcsh:Nutrition. Foods and food supply ,Food Science - Abstract
Background: Dietary supplements purported to increase circulating nitric oxide are very popular among consumers. We determined the acute impact of two novel dietary supplements on plasma nitrate/nitrite (NOx) and nitrite alone. Methods: 20 men and women (age: 24 ±, 5 years) ingested two different nitrate-rich supplements (Resync Recovery Blend at 7.5 g and 15 g, Resync Collagen Blend at 21 g), or placebo, on four different days. Fasting blood samples were obtained before and 75 min following ingestion and analyzed for NOx and nitrite. Results: Nitrite was not differently impacted by treatment (p >, 0.05). The NOx response for men and women was very similar, with no sex interactions noted (p >, 0.05). Condition (p <, 0.0001), time (p <, 0.0001), and condition x time (p <, 0.0001) effects were noted for NOx. Values increased from baseline to post-ingestion for the Resync Recovery Blend at 7.5 g (11 ±, 9 to 101 ±, 48 µ, M) and at 15 g (9 ±, 5 to 176 ±, 91µ, M), as well as for the Resync Collagen Blend (9 ±, 9 to 46 ±, 21µ, M), while values for placebo remained stable (9 ±, 7 to 8 ±, 5µ, M). Conclusion: While nitrite alone was not impacted by treatment, both Resync products result in an increase in plasma NOx, with the increase proportionate to the quantity of &ldquo, nitric oxide blend&rdquo, ingredients contained within each product. Future studies are needed to determine the physiological implications of the increased NOx, as pertaining to exercise performance and recovery, in addition to other aspects of human health.
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- 2020
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36. PI 3-kinase delta enhances axonal PIP3 to support axon regeneration in the adult CNS
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Charles ffrench-Constant, Craig S Pearson, Amanda C. Barber, Keith R Martin, Bart Nieuwenhuis, Tasneem Z Khatib, Patrice D. Smith, Rachel S Evans, Lianne A Hulshof, Joachim Fuchs, Richard Eva, Klaus Okkenhaug, Raquel D. Conceição, Sarita S Deshpande, Britta J. Eickholt, Andrew Osborne, Joshua Cave, James W. Fawcett, Barbara Haenzi, Susan van Erp, Amy R. MacQueen, Netherlands Institute for Neuroscience (NIN), Okkenhaug, Klaus [0000-0002-9432-4051], Martin, Keith [0000-0002-9347-3661], Fawcett, James [0000-0002-7990-4568], Eva, Richard [0000-0003-0305-0452], and Apollo - University of Cambridge Repository
- Subjects
0301 basic medicine ,Adult ,Central Nervous System ,Medicine (General) ,animal structures ,Central nervous system ,CNS axon regeneration ,p110 delta ,P110α ,QH426-470 ,optic nerve ,03 medical and health sciences ,Mice ,Phosphatidylinositol 3-Kinases ,0302 clinical medicine ,R5-920 ,medicine ,Genetics ,Animals ,Humans ,Axon ,PI3K/AKT/mTOR pathway ,Neurons ,Phosphoinositide 3-kinase ,biology ,Regeneration (biology) ,phosphoinositide 3-kinase ,axon transport ,phosphoinositide 3‐kinase ,Axons ,Nerve Regeneration ,Rats ,030104 developmental biology ,medicine.anatomical_structure ,nervous system ,Peripheral nervous system ,embryonic structures ,Optic nerve ,biology.protein ,Molecular Medicine ,Neuroscience ,030217 neurology & neurosurgery - Abstract
Peripheral nervous system (PNS) neurons support axon regeneration into adulthood, whereas central nervous system (CNS) neurons lose regenerative ability after development. To better understand this decline whilst aiming to improve regeneration, we focused on phosphoinositide 3‐kinase (PI3K) and its product phosphatidylinositol (3,4,5)‐trisphosphate (PIP3). We demonstrate that adult PNS neurons utilise two catalytic subunits of PI3K for axon regeneration: p110α and p110δ. However, in the CNS, axonal PIP3 decreases with development at the time when axon transport declines and regenerative competence is lost. Overexpressing p110α in CNS neurons had no effect; however, expression of p110δ restored axonal PIP3 and increased regenerative axon transport. p110δ expression enhanced CNS regeneration in both rat and human neurons and in transgenic mice, functioning in the same way as the hyperactivating H1047R mutation of p110α. Furthermore, viral delivery of p110δ promoted robust regeneration after optic nerve injury. These findings establish a deficit of axonal PIP3 as a key reason for intrinsic regeneration failure and demonstrate that native p110δ facilitates axon regeneration by functioning in a hyperactive fashion.
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- 2020
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37. Efficacy and Safety of the Ab-interno Xen Gel Stent After Failed Trabeculectomy
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Keith R Martin, Ayesha Karimi, Dan Lindfield, and Marina Hopes
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Male ,Intraocular pressure ,medicine.medical_specialty ,genetic structures ,medicine.medical_treatment ,Ocular hypertension ,Glaucoma ,Trabeculectomy ,03 medical and health sciences ,0302 clinical medicine ,Occlusion ,medicine ,Humans ,Glaucoma Drainage Implants ,Intraocular Pressure ,Aged ,Retrospective Studies ,Aged, 80 and over ,business.industry ,Stent ,Retrospective cohort study ,Middle Aged ,medicine.disease ,Surgery ,Ophthalmology ,Filtering Surgery ,030221 ophthalmology & optometry ,Female ,Ocular Hypertension ,Stents ,Implant ,business ,030217 neurology & neurosurgery - Abstract
AIMS: To assess the efficacy and safety of the Xen gel stent in reducing intraocular pressure (IOP) in eyes with prior failed trabeculectomy and to determine the frequency of complications and further intervention. METHODS: Retrospective case note review of all patients with prior trabeculectomy undergoing Xen surgery across 5 centers from August 2015 to May 2017. RESULTS: In total, 17 surgeries were reviewed. IOP reduced from 21.5 (±2.4) mm Hg preoperatively to 13.6 (±3.4) mm Hg at month 12 (P
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- 2018
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38. Latanoprostene Bunod 0.024% in Subjects With Open-angle Glaucoma or Ocular Hypertension: Pooled Phase 3 Study Findings
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Paul L. Kaufman, Jeffrey M. Liebmann, Robert N. Weinreb, Keith R Martin, and Jason L Vittitow
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Male ,Aging ,Intraocular pressure ,genetic structures ,Visual Acuity ,Phases of clinical research ,Ocular hypertension ,Glaucoma ,Neurodegenerative ,Ophthalmology & Optometry ,Original Studies ,law.invention ,0302 clinical medicine ,Randomized controlled trial ,law ,80 and over ,latanoprostene bunod ,Medicine ,nitric oxide donor ,Aged, 80 and over ,Cross-Over Studies ,Middle Aged ,prostaglandin analog ,Latanoprostene Bunod ,Open-Angle ,6.1 Pharmaceuticals ,Prostaglandins F, Synthetic ,Timolol ,Female ,Patient Safety ,Glaucoma, Open-Angle ,Adult ,safety ,medicine.medical_specialty ,Open angle glaucoma ,Clinical Trials and Supportive Activities ,Clinical Sciences ,open-angle glaucoma ,and over ,Tonometry ,Tonometry, Ocular ,Young Adult ,03 medical and health sciences ,i<%2Fbold>ntraocular+pressure%22"> ,i ntraocular pressureDouble-Blind Method ,Clinical Research ,Ocular ,Ophthalmology ,Humans ,diurnal ,Eye Disease and Disorders of Vision ,Antihypertensive Agents ,Intraocular Pressure ,Aged ,business.industry ,Prostaglandins F ,Synthetic ,Neurosciences ,Evaluation of treatments and therapeutic interventions ,medicine.disease ,Crossover study ,eye diseases ,030221 ophthalmology & optometry ,ocular hypertension ,Ocular Hypertension ,sense organs ,Ophthalmic Solutions ,business ,030217 neurology & neurosurgery - Abstract
PURPOSE:To compare the diurnal intraocular pressure (IOP)-lowering effect of latanoprostene bunod (LBN) 0.024% with timolol maleate 0.5% in subjects with open-angle glaucoma (OAG) or ocular hypertension (OHT). PATIENTS AND METHODS:Pooled analysis of two phase 3, randomized, multicenter, double-masked, parallel-group, noninferiority trials (APOLLO and LUNAR), each with open-label safety extension phases. Adults with OAG or OHT were randomized 2:1 to double-masked treatment with LBN once daily (qd) or timolol twice daily (bid) for 3 months followed by open-label LBN treatment for 3 (LUNAR) or 9 (APOLLO) months. IOP was measured at 8 AM, 12 PM, and 4 PM at week 2, week 6, and months 3, 6, 9, and 12. RESULTS:Of the 840 subjects randomized, 774 (LBN, n=523; timolol crossover to LBN, n=251) completed the efficacy phase, and 738 completed the safety extension phase. Mean IOP was significantly lower with LBN versus timolol at all 9 evaluation timepoints during the efficacy phase (P
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- 2018
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39. Can Home Monitoring Allow Earlier Detection of Rapid Visual Field Progression in Glaucoma?
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Algis J. Vingrys, Yu Xiang George Kong, Keith R Martin, Andrew J. Anderson, and Phillip Bedggood
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Adult ,Male ,medicine.medical_specialty ,Intraocular pressure ,Population ,Vision Disorders ,Ocular hypertension ,Glaucoma ,Audiology ,Sensitivity and Specificity ,Cohort Studies ,03 medical and health sciences ,0302 clinical medicine ,Humans ,Medicine ,Computer Simulation ,education ,Intraocular Pressure ,Aged ,Monitoring, Physiologic ,Decibel ,Aged, 80 and over ,education.field_of_study ,business.industry ,Middle Aged ,medicine.disease ,Visual field ,Ophthalmology ,Early Diagnosis ,Cohort ,Disease Progression ,030221 ophthalmology & optometry ,Visual Field Tests ,Optometry ,Female ,Ocular Hypertension ,Visual Fields ,Glaucoma, Angle-Closure ,business ,Glaucoma, Open-Angle ,030217 neurology & neurosurgery ,Follow-Up Studies ,Cohort study - Abstract
Purpose Recent developments in electronic technology are making it possible to home monitor the sensitivity of the central visual field using portable devices. We used simulations to investigate whether the higher test frequency afforded by home monitoring improves the early detection of rapid visual field loss in glaucoma and how any benefits might be affected by imperfect compliance or increased variability in the home-monitoring test. Design Computer simulation, with parameter selection confirmed with a cohort study. Participants A total of 43 patients with treated glaucoma (both open-angle and closed-angle), ocular hypertension or glaucoma suspects (mean age, 71 years; range, 37–89 years), were followed in the cohort study. Methods We simulated series (n = 100 000) of visual fields for patients with stable glaucoma and patients with progressing glaucoma for 2 in-clinic (yearly and 6-monthly) and 3 home-monitoring (monthly, fortnightly, and weekly) schedules, each running over a 5-year period. Various percentages of home-monitored fields were omitted at random to simulate reduced compliance, and the variability of the home monitored fields also was manipulated. We used previously published variability characteristics for perimetry and confirmed their appropriateness for a home-monitoring device by measuring the device's retest variability at 2 months in a cohort of 43 patients. The criterion for flagging progression in our simulation was a significant slope of the ordinary least squares regression of a simulated patient's mean deviation (MD) data. Main Outcome Measures The sensitivity for identifying rapid visual field loss (−2 decibels [dB]/year loss of MD). Results Although a sensitivity of 0.8 for rapid field loss was achieved after 2.5 years of 6-monthly testing in the clinic, weekly home monitoring achieved this by 0.9 years despite moderate test compliance of 63%. The improved performance of weekly home monitoring over 6-monthly clinical testing was retained even when home monitoring was assumed to produce more variable test results or be associated with low patient compliance. Conclusions Detecting rapid visual field progression may be improved using a home-monitoring strategy, even when compliance is imperfect. The cost-benefit of such an approach is yet to be demonstrated, however.
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- 2017
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40. Surgical outcomes of trabeculectomy and glaucoma drainage implant for uveitic glaucoma and relationship with uveitis activity
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Jonathan B Ruddle, Catherine M Green, Yu Xiang George Kong, Lingwei William Tao, Jonathan G Crowston, Lyndell L Lim, Hye Jin Kwon, and Keith R Martin
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0301 basic medicine ,medicine.medical_specialty ,Intraocular pressure ,Visual acuity ,business.industry ,medicine.medical_treatment ,Glaucoma ,Retrospective cohort study ,Odds ratio ,medicine.disease ,Surgery ,03 medical and health sciences ,Ophthalmology ,030104 developmental biology ,0302 clinical medicine ,Endophthalmitis ,030221 ophthalmology & optometry ,medicine ,Trabeculectomy ,medicine.symptom ,business ,Uveitis - Abstract
Importance This study provides ophthalmologists who manage uveitic glaucoma with important information on factors that can affect the success of surgical management of this challenging disease. Background This study examines surgical outcomes of trabeculectomy and glaucoma device implant (GDI) surgery for uveitic glaucoma, in particular the effect of uveitis activity on surgical outcomes. Design Retrospective chart review at a tertiary institution. Samples 82 cases with uveitic glaucoma (54 trabeculectomies, 28 GDI surgeries) performed between 1 December 2006 and 30 November 2014. Methods Associations of factors with surgical outcomes were examined using univariate and multivariate analysis. Main Outcome Measures Surgical outcomes (failure, success and qualified success) as defined in Guidelines from World Glaucoma Association. Results Average follow up was 26.4 ± 21.5 months. Anterior uveitis was the most common uveitis type. Overall qualified success rate of the trabeculectomies was not statistically different to GDI, being 67% and 75% respectively (P = 0.60). Primary GDI and secondary GDI operations showed similar success rates. The most common post-operative complication was hypotony (~30%). Two cases of GDI developed endophthalmitis and none in trabeculectomies. Active uveitis at the time of operation was higher in trabeculectomy compared to GDI group (35% vs. 14%). Active uveitis at the time of surgery did not significantly increase risk of failure for trabeculectomies. Recurrence of uveitis was significantly associated with surgical failure in trabeculectomy group (odds ratio OR 4.8, P = 0.02) but not in GDI group. Conclusions and Relevance Surgical success rate of GDI was not significantly different to trabeculectomy for uveitic glaucoma in this study. Regular monitoring, early and prolonged intensive treatment of ocular inflammation is important for surgical success particularly following trabeculectomy.
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- 2017
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41. The role and mechanism of retinal ganglion cell death in glaucomatous injury
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James R. Tribble, James Edwards Morgan, Matthew Felgate, Keith R Martin, Andrew Osborne, Robert Watt, Terrance Mensah, Tasneem Z Khatib, and Zara Ali
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Ophthalmology ,medicine.anatomical_structure ,Retinal ganglion cell ,Mechanism (biology) ,business.industry ,medicine ,General Medicine ,business ,Neuroscience - Published
- 2019
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42. PI 3-kinase delta enhances axonal PIP
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Bart, Nieuwenhuis, Amanda C, Barber, Rachel S, Evans, Craig S, Pearson, Joachim, Fuchs, Amy R, MacQueen, Susan, van Erp, Barbara, Haenzi, Lianne A, Hulshof, Andrew, Osborne, Raquel, Conceicao, Tasneem Z, Khatib, Sarita S, Deshpande, Joshua, Cave, Charles, Ffrench-Constant, Patrice D, Smith, Klaus, Okkenhaug, Britta J, Eickholt, Keith R, Martin, James W, Fawcett, and Richard, Eva
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Adult ,Central Nervous System ,Neurons ,CNS axon regeneration ,p110 delta ,Articles ,axon transport ,Regenerative Medicine ,Axons ,Article ,optic nerve ,phosphoinositide 3‐kinase ,Nerve Regeneration ,Rats ,Mice ,Phosphatidylinositol 3-Kinases ,nervous system ,Animals ,Humans ,Neuroscience - Abstract
Peripheral nervous system (PNS) neurons support axon regeneration into adulthood, whereas central nervous system (CNS) neurons lose regenerative ability after development. To better understand this decline whilst aiming to improve regeneration, we focused on phosphoinositide 3‐kinase (PI3K) and its product phosphatidylinositol (3,4,5)‐trisphosphate (PIP 3). We demonstrate that adult PNS neurons utilise two catalytic subunits of PI3K for axon regeneration: p110α and p110δ. However, in the CNS, axonal PIP 3 decreases with development at the time when axon transport declines and regenerative competence is lost. Overexpressing p110α in CNS neurons had no effect; however, expression of p110δ restored axonal PIP 3 and increased regenerative axon transport. p110δ expression enhanced CNS regeneration in both rat and human neurons and in transgenic mice, functioning in the same way as the hyperactivating H1047R mutation of p110α. Furthermore, viral delivery of p110δ promoted robust regeneration after optic nerve injury. These findings establish a deficit of axonal PIP 3 as a key reason for intrinsic regeneration failure and demonstrate that native p110δ facilitates axon regeneration by functioning in a hyperactive fashion., CNS axons lose the ability to regenerate with maturity, whilst PNS axons do not. This study shows that PIP3 levels decline in CNS neurons at the time when regenerative ability is lost. CNS overexpression of one isoform of PI3K, p110δ, enhances axonal PIP3, axon transport, and regenerative ability.
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- 2019
43. Expression of Developmentally Important Axon Guidance Cues in the Adult Optic Chiasm
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Sarita S Deshpande, Andrew Osborne, Keith R Martin, Barbara Hänzi, Amanda C. Barber, Raquel D. Conceição, Rachel S Evans, Craig S Pearson, Martin, Keith [0000-0002-9347-3661], and Apollo - University of Cambridge Repository
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0301 basic medicine ,Retinal Ganglion Cells ,Optic tract ,optic chiasm guidance cues ,genetic structures ,Nerve Crush ,Optic chiasm ,Nerve Tissue Proteins ,Biology ,Inhibitory postsynaptic potential ,03 medical and health sciences ,Mice ,0302 clinical medicine ,Pregnancy ,SLIT1 ,medicine ,Animals ,Microscopy, Confocal ,Regeneration (biology) ,PAX2 Transcription Factor ,Brain ,Gene Expression Regulation, Developmental ,General Medicine ,Anatomy ,Immunohistochemistry ,eye diseases ,Axon Guidance ,Mice, Inbred C57BL ,030104 developmental biology ,medicine.anatomical_structure ,Optic Chiasm ,Optic Nerve Injuries ,Optic nerve ,Axon guidance ,Female ,Anatomy and Pathology/Oncology ,sense organs ,Cues ,Fatty Acid-Binding Protein 7 ,030217 neurology & neurosurgery ,Biomarkers - Abstract
Funder: Wellcome Trust, PURPOSE: Regeneration of optic nerve axons after injury can be facilitated by several approaches, but misguidance at the optic chiasm is often observed. We characterized guidance cues in the embryonic visual system and adult optic chiasm before and after optic nerve crush (ONC) injury to better understand barriers to optic nerve regeneration in adults. METHODS: Radial glial (RC2/BLBP/Slit1), developmental (Pax2) and extracellular markers (CSPG: H2B/CS-56) were assessed in C57BL/6J mice by immunohistochemistry. RC2, BLBP, Slit1, and CSPG are known inhibitory guidance cues while Pax2 is a permissive guidance cue. RESULTS: At embryonic day 15.5 (E.15.5), RC2 and BLBP were identified superior to, and extending through, the optic chiasm. The optic chiasm was BLBP-ve in adult uninjured mice but BLBP+ve in adult mice 10 days after ONC injury. The reverse was true for RC2. Both BLBP and RC2 were absent in adult mice 6 weeks post-ONC. Slit1 was present in the optic chiasm midline and optic tracts in embryonic samples but was absent in uninjured adult tissue. Slit1 was observed superior to and at the midline of the optic chiasm 10 days post-ONC but absent 6 weeks after injury. Pax2 was expressed at the junction between the optic nerve and optic chiasm in embryonic brain tissue. In embryonic sections, CS-56 was observed at the junction between the optic chiasm and optic tract, and immediately superior to the optic chiasm. Both 2H6 and CS-56 staining was absent in uninjured and ONC-injured adult brains. CONCLUSION: Differences in guidance cue expression during development, in adulthood and after injury may contribute to misguidance of regenerating RGC axons in the adult optic chiasm.
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- 2019
44. PI 3-kinase delta enhances axonal PIP3 to support axon regeneration in the adult CNS
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Joachim Fuchs, Raquel D. Conceição, Bart Nieuwenhuis, Barabara Haenzi, James W. Fawcett, Charles ffrench-Constant, Klaus Okkenhaug, Patrice D. Smith, Susan van Erp, Richard Eva, Keith R Martin, Britta J. Eickholt, Andrew Osborne, Craig S Pearson, Rachel S Evans, Amy R. MacQueen, Amanda C. Barber, Sarita S Deshpande, Joshua Cave, and Lianne A Hulshof
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Genetically modified mouse ,0303 health sciences ,animal structures ,Regeneration (biology) ,Central nervous system ,Cell ,Biology ,Cell biology ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,medicine.anatomical_structure ,nervous system ,chemistry ,Peripheral nervous system ,embryonic structures ,medicine ,Phosphatidylinositol ,Axon ,030217 neurology & neurosurgery ,PI3K/AKT/mTOR pathway ,030304 developmental biology - Abstract
Peripheral nervous system (PNS) neurons support axon regeneration into adulthood, whereas central nervous system (CNS) neurons lose regenerative ability after development. To better understand this decline whilst aiming to improve regeneration, we focused on phosphoinositide 3-kinase (PI3K) and its product phosphatidylinositol(3,4,5)-trisphosphate (PIP3). We found that neuronal PIP3 decreases with maturity in line with regenerative competence, firstly in the cell body and subsequently in the axon. We show that adult PNS neurons utilise two catalytic subunits of PI3K for efficient regeneration: p110 and p110{delta}. Overexpressing p110 in CNS neurons had no effect, however expression of p110{delta} restored axonal PIP3 and enhanced CNS regeneration in rat and human neurons and in transgenic mice, functioning in the same way as the hyperactivating H1047R mutation of p110. Furthermore, viral delivery of p110{delta} promoted robust regeneration after optic nerve injury. These findings demonstrate a deficit of axonal PIP3 as a reason for intrinsic regeneration failure and show that native p110{delta} facilitates axon regeneration by functioning in a hyperactive fashion.
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- 2019
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45. Angiopoietins in Diabetic Retinopathy: Current Understanding and Therapeutic Potential
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Keith R Martin, Michael Whitehead, Patrick Yu-Wai-Man, Andrew Osborne, Peter Widdowson, Whitehead, Michael [0000-0002-5494-8302], Martin, Keith R [0000-0002-9347-3661], Apollo - University of Cambridge Repository, Yu-Wai-Man, Patrick [0000-0001-7847-9320], and Martin, Keith [0000-0002-9347-3661]
- Subjects
0301 basic medicine ,Article Subject ,Angiogenesis ,Endocrinology, Diabetes and Metabolism ,Population ,Disease ,Review Article ,Bioinformatics ,lcsh:Diseases of the endocrine glands. Clinical endocrinology ,Macular Edema ,Angiopoietin ,Diabetes Complications ,03 medical and health sciences ,0302 clinical medicine ,Endocrinology ,Diabetes mellitus ,medicine ,Diabetes Mellitus ,Animals ,Humans ,Hypoglycemic Agents ,education ,health care economics and organizations ,education.field_of_study ,lcsh:RC648-665 ,Diabetic Retinopathy ,biology ,business.industry ,Angiopoietins ,Diabetic retinopathy ,medicine.disease ,Angiopoietin receptor ,3. Good health ,030104 developmental biology ,030220 oncology & carcinogenesis ,biology.protein ,cardiovascular system ,business ,hormones, hormone substitutes, and hormone antagonists ,Signal Transduction - Abstract
Diabetic retinopathy (DR) is the commonest cause of blindness in the working-age population of the developed world. The molecular pathophysiology of DR is complex, and a complete spatiotemporal model of the disease is still being elucidated. Recently, a role for angiopoietin (Ang) proteins in the pathophysiology of DR has been proposed by several research groups, and several aspects of Ang signalling are being explored as novel therapeutic strategies. Here, we review the role of the Ang proteins in two important forms of DR, diabetic macular oedema and proliferative diabetic retinopathy. The function of the Ang proteins in regulating blood vessel permeability and neovascularisation is discussed, and we also evaluate recent preclinical and clinical studies highlighting the potential benefits of modulating Ang signalling as a treatment for DR.
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- 2019
46. Comparison of Latanoprostene Bunod 0.024% and Timolol Maleate 0.5% in Open-Angle Glaucoma or Ocular Hypertension: The LUNAR Study
- Author
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Robert N. Weinreb, Felipe A. Medeiros, Keith R Martin, Jason L Vittitow, James H. Peace, Baldo Scassellati Sforzolini, Martin, Keith [0000-0002-9347-3661], and Apollo - University of Cambridge Repository
- Subjects
Adult ,Male ,Intraocular pressure ,medicine.medical_specialty ,Evening ,genetic structures ,Visual Acuity ,Timolol ,Ocular hypertension ,Glaucoma ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Double-Blind Method ,Ophthalmology ,medicine ,Humans ,media_common.cataloged_instance ,Prospective Studies ,European union ,Prospective cohort study ,Antihypertensive Agents ,Intraocular Pressure ,Aged ,Morning ,media_common ,Aged, 80 and over ,Analysis of Variance ,business.industry ,Middle Aged ,medicine.disease ,eye diseases ,Anesthesia ,Prostaglandins F, Synthetic ,030221 ophthalmology & optometry ,Female ,Ocular Hypertension ,sense organs ,Ophthalmic Solutions ,business ,Glaucoma, Open-Angle ,030217 neurology & neurosurgery ,medicine.drug - Abstract
Purpose To compare the intraocular pressure (IOP)-lowering effect of latanoprostene bunod (LBN) 0.024% with timolol maleate 0.5% in subjects with open-angle glaucoma (OAG) or ocular hypertension (OHT). Design Prospective, randomized, double-masked, parallel-group, noninferiority clinical trial. Methods Adults with OAG or OHT from 46 clinical sites (United States and European Union) were randomized 2:1 to LBN instilled once daily (QD) in the evening and vehicle in the morning or timolol instilled twice a day (BID) for 3 months. IOP was measured at week 2, week 6, and month 3 (8 AM, 12 PM, and 4 PM each visit). Results A total of 387 subjects (LBN, n = 259; timolol, n = 128) completed the study. Analysis of covariance showed that mean IOP reduction with LBN was not only noninferior to timolol but significantly greater ( P ≤ .025) than timolol at all but the first time point in this study (week 2, 8 AM). Of LBN- and timolol-treated subjects, respectively, 31.0% and 18.5% ( P = .007) had their IOP reduced ≥25% from baseline, and 17.7% and 11.1% ( P = .084) had their IOP reduced to ≤18 mm Hg over all time points/visits in this study. Ocular treatment-emergent adverse events, while uncommon, appeared more frequently in the LBN group (all mild-moderate except 1 case of severe hyperemia). Conclusions LBN 0.024% QD in the evening was noninferior to timolol 0.5% BID over 3 months of treatment, with significantly greater IOP lowering in subjects with OAG or OHT at all but the earliest time point evaluated, and demonstrated a good safety profile.
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- 2016
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47. Three-dimensional printing of the retina
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Wen-Kai Hsiao, Barbara Lorber, and Keith R Martin
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0301 basic medicine ,TRANSLATIONAL RESEARCH: Edited by Jason Hsu and Sunir J. Garg ,Retinal Ganglion Cells ,medicine.medical_specialty ,business.industry ,functional retina ,Nanotechnology ,02 engineering and technology ,General Medicine ,021001 nanoscience & nanotechnology ,Retina ,Transplantation ,03 medical and health sciences ,Ophthalmology ,030104 developmental biology ,Three dimensional printing ,Printing, Three-Dimensional ,medicine ,Humans ,Medical physics ,three-dimensional printing ,0210 nano-technology ,business ,Neuroglia ,retinal cells - Abstract
Purpose of review Biological three-dimensional printing has received a lot of media attention over recent years with advances made in printing cellular structures, including skin and heart tissue for transplantation. Although limitations exist in creating functioning organs with this method, the hope has been raised that creating a functional retina to cure blindness is within reach. The present review provides an update on the advances made toward this goal. Recent findings It has recently been shown that two types of retinal cells, retinal ganglion cells and glial cells, can be successfully printed using a piezoelectric inkjet printer. Importantly, the cells remained viable and did not change certain phenotypic features as a result of the printing process. In addition, recent advances in the creation of complex and viable three-dimensional cellular structures have been made. Summary Some first promising steps toward the creation of a functional retina have been taken. It now needs to be investigated whether recent findings can be extended to other cells of the retina, including those derived from human tissue, and if a complex and viable retinal structure can be created through three-dimensional printing.
- Published
- 2016
48. Impact of age-related macular degeneration in patients with glaucoma: understanding the patients' perspective
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Eva K Fenwick, Ivan Goldberg, Peter McCluskey, Simon E. Skalicky, Keith R Martin, and Jonathan G Crowston
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medicine.medical_specialty ,Visual acuity ,genetic structures ,Open angle glaucoma ,business.industry ,Cross-sectional study ,Eye disease ,Glaucoma ,Macular degeneration ,medicine.disease ,eye diseases ,Confidence interval ,Visual field ,03 medical and health sciences ,Ophthalmology ,0302 clinical medicine ,030221 ophthalmology & optometry ,medicine ,sense organs ,030212 general & internal medicine ,medicine.symptom ,business - Abstract
BACKGROUND The aim of the study is to measure the impact of age-related macular degeneration on vision-related activity limitation and preference-based status for glaucoma patients. DESIGN This was a cross-sectional study. PARTICIPANTS Two-hundred glaucoma patients of whom 73 had age-related macular degeneration were included in the research. METHODS Sociodemographic information, visual field parameters and visual acuity were collected. Age-related macular degeneration was scored using the Age-Related Eye Disease Study system. MAIN OUTCOME MEASURES The Rasch-analysed Glaucoma Activity Limitation-9 and the Visual Function Questionnaire Utility Index measured vision-related activity limitation and preference-based status, respectively. Regression models determined factors predictive of vision-related activity limitation and preference-based status. Differential item functioning compared Glaucoma Activity Limitation-9 item difficulty for those with and without age-related macular degeneration. RESULTS Mean age was 73.7 (±10.1) years. Lower better eye mean deviation (β: 1.42, 95% confidence interval: 1.24-1.63, P
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- 2016
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49. Spatiotemporal distribution of chondroitin sulfate proteoglycans after optic nerve injury in rodents
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Andrea G. Solano, Caitlin P. Mencio, Herbert M. Geller, Craig S Pearson, Sharada Tilve, and Keith R Martin
- Subjects
0301 basic medicine ,animal structures ,Central nervous system ,Retina ,Trimethoprim ,Article ,Glial scar ,Rats, Sprague-Dawley ,Crush Injuries ,Mice ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,Versicans ,0302 clinical medicine ,Neurocan ,medicine ,Animals ,Aggrecans ,Brevican ,Aggrecan ,Glycosaminoglycans ,Sulfamonomethoxine ,biology ,Receptor-Like Protein Tyrosine Phosphatases, Class 5 ,Chemistry ,Optic Nerve ,Immunohistochemistry ,Sensory Systems ,Rats ,Cell biology ,Mice, Inbred C57BL ,Disease Models, Animal ,Drug Combinations ,Ophthalmology ,030104 developmental biology ,medicine.anatomical_structure ,Chondroitin Sulfate Proteoglycans ,Optic Nerve Injuries ,030221 ophthalmology & optometry ,biology.protein ,Optic nerve ,Versican ,Female ,sense organs - Abstract
The accumulation of chondroitin sulfate proteoglycans (CSPGs) in the glial scar following acute damage to the central nervous system (CNS) limits the regeneration of injured axons. Given the rich diversity of CSPG core proteins and patterns of GAG sulfation, identifying the composition of these CSPGs is essential for understanding their roles in injury and repair. Differential expression of core proteins and sulfation patterns have been characterized in the brain and spinal cord of mice and rats, but a comprehensive study of these changes following optic nerve injury has not yet been performed. Here, we show evidence that the composition of CSPGs in the optic nerve and retina following optic nerve crush (ONC) in mice and rats exhibits an increase in aggrecan, brevican, phosphacan, neurocan and versican, similar to changes following spinal cord injury. We also observe an increase in inhibitory 4-sulfated (4S) GAG chains, which suggests that the persistence of CSPGs in the glial scar opposes the growth of CNS axons, thereby contributing to the failure of regeneration and recovery of function.
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- 2020
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50. Consumption of 100% Tart Cherry Juice Reduces Serum Urate in Overweight and Obese Adults
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Keith R Martin and Katie M Coles
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medicine.medical_specialty ,Medicine (miscellaneous) ,Overweight ,Gastroenterology ,metabolic syndrome ,tart cherry juice ,Cherry juice ,serum urate ,Internal medicine ,medicine ,overweight/obese ,Hyperuricemia ,Risk factor ,Nutrition in Health and Disease ,comic_books.series ,Original Research ,Nutrition and Dietetics ,business.industry ,medicine.disease ,Obesity ,Gout ,hsCRP ,comic_books ,medicine.symptom ,Metabolic syndrome ,business ,Body mass index ,Food Science ,MCP-1 - Abstract
Background Gout is a frequently occurring, complex rheumatologic form of inflammatory arthritis caused by the accumulation of serum uric acid (sUA) and deposition of uric acid crystals in the joints and tissues of the body. Hyperuricemia is also a significant independent risk factor for all-cause and cardiovascular morbidity and mortality and is associated with hypertension, diabetes, obesity, and osteoarthritis. However, patient adherence to prescribed urate-lowering therapies ranges from 20% to 70%, suggesting that other additional strategies, such as dietary intervention with specific, efficacious foods or beverages, may be necessary to mitigate the risk of arthritis, as well as other comorbidities. Tart cherry juice (TCJ) has been used for decades by some for gout based largely on anecdotal evidence of its efficacy and its antioxidant and anti-inflammatory properties. Objectives We designed this study to test the effect of TCJ on uricemia, lipidemia, glycemia, and inflammation in at-risk overweight and obese humans with a specific hypothesis that TCJ consumption would reduce sUA concentrations. Methods In this randomized, placebo-controlled crossover study, we recruited overweight and obese participants with body mass index (BMI) >25.0 kg/m2 (n = 26, 18 women/8 men, 41 ±11 y; BMI 31.3 ± 6.0; 12 obese, 14 overweight) to consume 240 mL/d (8 oz/d) of either TCJ or placebo beverage, for 4 wk each with a 4-wk intervening washout period followed by 4 wk of the alternate beverage. Results TCJ significantly reduced sUA concentration by 19.2% (P
- Published
- 2018
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