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1.
JAMA Ophthalmol ; 2024 Jun 20.
Article in English | MEDLINE | ID: mdl-38900484

ABSTRACT

Importance: Intraocular pressure (IOP) elevations of clinical relevance have been observed after the commonly used 0.05-mL volume for intravitreous injections. However, more recently approved intravitreous agents involve volumes from 0.07 to 0.1 mL. It is not well established whether repeated 0.1-mL intravitreous injections may result in IOP-related complications. Objective: To investigate the effect of 1 year of repeated 0.1-mL intravitreous injections on IOP outcomes. Design, Setting, and Participants: This study was a post hoc analysis of 2 clinical trials investigating the IOP safety of intravitreous lampalizumab on geographic atrophy secondary to age-related macular degeneration. Both trials were conducted between 2014 and 2018 and recruited participants who were 50 years or older and had bilateral geographic atrophy. This post hoc analysis was performed between 2018 and 2022. Interventions: Intravitreous lampalizumab, 0.1 mL, every 4 weeks; lampalizumab, 0.1 mL, every 6 weeks; or sham procedure every 4 weeks or 6 weeks for 48 weeks. Main Outcomes and Measures: IOP changes in the 4-week-frequency study arms and ocular adverse events to week 48 in all arms. The hypothesis for this analysis was formulated after data collection. Results: Among a total of 1851 participants, there was no change in mean pre-injection IOP values through 48 weeks in either arm. The adverse events glaucoma and ocular hypertension were reported for 1.8% of participants treated with lampalizumab and 1.6% of those in the sham arm. Conclusions and Relevance: Over 1 year, IOP increases were rare and did not affect treated participants more frequently than sham arm participants. These findings support the low risk of persistent IOP increases, on average, of intravitreous 0.1-mL injection volumes administered for 1 year in a manner similar to that performed in these clinical trials. These results may be valuable in the design of future therapeutic trials considering this volume for injections particularly as more recently approved agents use volumes of 0.07 to 0.1 mL. Trial Registration: ClinicalTrials.gov Identifiers: NCT02247479 and NCT02247531.

2.
Ophthalmol Ther ; 13(6): 1407-1416, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38704812

ABSTRACT

The pending introduction of home-based optical coherence tomography (OCT) in managing neovascular age-related macular degeneration (nAMD) has sparked interesting debates. Advocates assert that home-based OCT will revolutionize care of patients with nAMD, while skeptics question its real-world viability and point out its potential drawbacks. This article delves into the dichotomy, presenting the "pro" argument highlighting the transformative potential of home OCT and the "con" perspective, which scrutinizes the limitations and challenges to adapting the technology to the real-world setting. By exploring both sides of the discourse, we aim to address the promises and complexities surrounding the role of home OCT in the management of nAMD.

3.
Retina ; 44(6): 939-949, 2024 Jun 01.
Article in English | MEDLINE | ID: mdl-38451179

ABSTRACT

PURPOSE: To develop professional guidelines for best practices for suprachoroidal space (SCS) injection, an innovative technique for retinal therapeutic delivery, based on current published evidence and clinical experience. METHODS: A panel of expert ophthalmologists reviewed current published evidence and clinical experience during a live working group meeting to define points of consensus and key clinical considerations to inform the development of guidelines for in-office SCS injection. RESULTS: Core consensus guidelines for in-office SCS injection were reached and reported by the expert panel. Current clinical evidence and physician experience supported SCS injection as a safe and effective method for delivering retinal and choroidal therapeutics. The panel established consensus on the rationale for SCS injection, including potential benefits relative to other intraocular delivery methods and current best practices in patient preparation, pre- and peri-injection management, SCS-specific injection techniques, and postinjection management and follow-up. CONCLUSION: These expert panel guidelines may support and promote standardization of SCS injection technique, with the goal of optimizing patient safety and outcomes. Some aspects of the procedure may reasonably be modified based on the clinical setting and physician judgment, as well as additional study.


Subject(s)
Choroid , Humans , Injections, Intraocular , Retinal Diseases , Practice Guidelines as Topic
4.
WMJ ; 123(1): 34-38, 2024 02.
Article in English | MEDLINE | ID: mdl-38436637

ABSTRACT

BACKGROUND: Given the need for a diverse health care workforce, efforts must be made early in their education to support underrepresented minorities in medicine and the science, technology, engineering, and mathematics (STEM) fields. METHODS: The Eyes on the Future program introduces underrepresented minority 8th grade students to science and medicine via interactive science-based programming and mentorship by medical and graduate students. Program impact was evaluated using pre- and post-program surveys. RESULTS: Of 25 participating students, 24 and 22 responded to pre- and post-program surveys, respectively. Students showed strong interest in science concepts and STEM careers, with high, positively correlated, and statistically similar pre- and post-program survey responses. DISCUSSION: The Eyes on the Future program was well-received and represents a step towards addressing barriers to STEM careers faced by underrepresented minority students.


Subject(s)
Schools , Technology , Adolescent , Humans , Educational Status , Hispanic or Latino , Mathematics
5.
FASEB J ; 38(5): e23512, 2024 Mar 15.
Article in English | MEDLINE | ID: mdl-38430220

ABSTRACT

The robust integrity of the retinal pigment epithelium (RPE), which contributes to the outer brain retina barrier (oBRB), is compromised in several retinal degenerative and vascular disorders, including diabetic macular edema (DME). This study evaluates the role of a new generation of histone deacetylase inhibitor (HDACi), ITF2357, in regulating outer blood-retinal barrier function and investigates the underlying mechanism of action in inhibiting TNFα-induced damage to RPE integrity. Using the immortalized RPE cell line (ARPE-19), ITF2357 was found to be non-toxic between 50 nM and 5 µM concentrations. When applied as a pre-treatment in conjunction with an inflammatory cytokine, TNFα, the HDACi was safe and effective in preventing epithelial permeability by fortifying tight junction (ZO-1, -2, -3, occludin, claudin-1, -2, -3, -5, -19) and adherens junction (E-cadherin, Nectin-1) protein expression post-TNFα stress. Mechanistically, ITF2357 depicted a late action at 24 h via attenuating IKK, IκBα, and p65 phosphorylation and ameliorated the expression of IL-1ß, IL-6, and MCP-1. Also, ITF2357 delayed IκBα synthesis and turnover. The use of Bay 11-7082 and MG132 further uncovered a possible role for ITF2357 in non-canonical NF-κB activation. Overall, this study revealed the protection effects of ITF2357 by regulating the turnover of tight and adherens junction proteins and modulating NF-κB signaling pathway in the presence of an inflammatory stressor, making it a potential therapeutic application for retinal vascular diseases such as DME with compromised outer blood-retinal barrier.


Subject(s)
Diabetic Retinopathy , Hydroxamic Acids , Macular Edema , Humans , NF-kappa B/metabolism , Diabetic Retinopathy/metabolism , NF-KappaB Inhibitor alpha/metabolism , Tumor Necrosis Factor-alpha/metabolism , Macular Edema/metabolism , Signal Transduction , Retinal Pigment Epithelium/metabolism , Blood-Retinal Barrier/metabolism , Tight Junctions/metabolism , Epithelial Cells/metabolism , Retinal Pigments/metabolism , Retinal Pigments/pharmacology , Retinal Pigments/therapeutic use
6.
Ophthalmic Surg Lasers Imaging Retina ; 55(3): 156-162, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38466965

ABSTRACT

Indicated for colorectal cancer for decades, bevacizumab has been widely used off label to treat retinal diseases, and the benefits of its use, specifically in neovascular age-related macular degeneration, have been demonstrated in multiple clinical trials. The intravitreal delivery of bevacizumab requires it to be aseptically repackaged into individual syringes by compounding pharmacies for use in the eye. Although the repackaging process is permitted by the US Food and Drug Administration, the resultant product does not meet the specific standards of products approved for use as ophthalmic injectables nor is the parenteral innovator solution compliant with ophthalmic standards. Studies have also demonstrated variability in the quality and quantity of repackaged bevacizumab. This narrative review summarizes the evidence and discusses the role of off-label bevacizumab in the treatment and management of retinal diseases, its mechanism of action, current challenges and provides a critical appraisal of current evidence, clinical implications, and future directions. [Ophthalmic Surg Lasers Imaging Retina 2024;55:155-162.].


Subject(s)
Macular Degeneration , Retinal Diseases , Humans , Bevacizumab/therapeutic use , Angiogenesis Inhibitors/therapeutic use , Angiogenesis Inhibitors/pharmacology , Injections , Macular Degeneration/drug therapy , Retinal Diseases/drug therapy , Intravitreal Injections
7.
Asia Pac J Ophthalmol (Phila) ; 13(1): 100036, 2024.
Article in English | MEDLINE | ID: mdl-38244930

ABSTRACT

Decades of studies on age-related macular degeneration (AMD), cardiovascular disease and stroke have not found consistent associations between AMD and systemic vascular disease. This study suggests that there is in fact no general relationship, but instead a strong, specific association between only the subretinal drusenoid deposit (SDD) phenotype of AMD on retinal imaging and certain co-existent vascular diseases that are high risk for compromised cardiac output or internal carotid artery stenosis. Future screening initiatives for these high -risk vascular diseases (HRVDs) with fast, inexpensive retinal imaging could make a significant contribution to public health and save lives. Likewise, screening patients with known HRVDs for unrecognized AMD of the SDD form could enable needed treatment and save vision.


Subject(s)
Cardiovascular Diseases , Macular Degeneration , Retinal Drusen , Vascular Diseases , Humans , Retinal Drusen/diagnosis , Retinal Drusen/complications , Cardiovascular Diseases/complications , Cardiovascular Diseases/diagnosis , Tomography, Optical Coherence/methods , Macular Degeneration/complications , Macular Degeneration/diagnosis , Vascular Diseases/complications , Fluorescein Angiography
8.
Am J Ophthalmol ; 262: 153-160, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38296152

ABSTRACT

PURPOSE: Nearly all published ophthalmology-related Big Data studies rely exclusively on International Classification of Diseases (ICD) billing codes to identify patients with particular ocular conditions. However, inaccurate or nonspecific codes may be used. We assessed whether natural language processing (NLP), as an alternative approach, could more accurately identify lens pathology. DESIGN: Database study comparing the accuracy of NLP versus ICD billing codes to properly identify lens pathology. METHODS: We developed an NLP algorithm capable of searching free-text lens exam data in the electronic health record (EHR) to identify the type(s) of cataract present, cataract density, presence of intraocular lenses, and other lens pathology. We applied our algorithm to 17.5 million lens exam records in the Sight Outcomes Research Collaborative (SOURCE) repository. We selected 4314 unique lens-exam entries and asked 11 clinicians to assess whether all pathology present in the entries had been correctly identified in the NLP algorithm output. The algorithm's sensitivity at accurately identifying lens pathology was compared with that of the ICD codes. RESULTS: The NLP algorithm correctly identified all lens pathology present in 4104 of the 4314 lens-exam entries (95.1%). For less common lens pathology, algorithm findings were corroborated by reviewing clinicians for 100% of mentions of pseudoexfoliation material and 99.7% for phimosis, subluxation, and synechia. Sensitivity at identifying lens pathology was better for NLP (0.98 [0.96-0.99] than for billing codes (0.49 [0.46-0.53]). CONCLUSIONS: Our NLP algorithm identifies and classifies lens abnormalities routinely documented by eye-care professionals with high accuracy. Such algorithms will help researchers to properly identify and classify ocular pathology, broadening the scope of feasible research using real-world data.


Subject(s)
Algorithms , Electronic Health Records , International Classification of Diseases , Lens, Crystalline , Natural Language Processing , Humans , Lens, Crystalline/pathology , Cataract/classification , Cataract/diagnosis , Lens Diseases/diagnosis , Male , Female
9.
J Vitreoretin Dis ; 8(1): 9-20, 2024.
Article in English | MEDLINE | ID: mdl-38223782

ABSTRACT

Purpose: To analyze post-marketing cases of retinal vasculitis after intravitreal pegcetacoplan. Methods: The American Society of Retina Specialists (ASRS) Research and Safety in Therapeutics (ReST) Committee as well as an expert panel performed a retrospective review of cases of retinal vasculitis reported to the ASRS. Clinical and imaging characteristics were reviewed for evidence of retinal vasculitis and analyzed. Results: Fourteen eyes of 13 patients were confirmed to have retinal vasculitis by review of imaging studies. All cases occurred after the first pegcetacoplan injection. Occlusive retinal vasculopathy was confirmed in 11 eyes (79%). Patients presented a median of 10.5 days (range, 8-23 days) after pegcetacoplan injection. All eyes had anterior chamber inflammation, and 12 eyes (86%) had vitritis. Vasculopathy involved retinal veins (100%) more than arteries (73%), and 12 eyes (86%) had retinal hemorrhages. The median visual acuity (VA) was 20/60 (range, 20/30-5/200) at baseline, 20/300 (range, 20/100-no light perception [NLP]) at vasculitis presentation, and 20/200 (range 20/70-NLP) at the last follow-up. Eight eyes (57%) had more than a 3-line decrease in VA, and 6 eyes (43%) had more than a 6-line decrease in VA from baseline to the final follow-up, including 2 eyes that were enucleated. Six eyes (43%) developed signs of anterior segment neovascularization. Conclusions: There is currently no known etiology for vasculitis in this series. Optimum treatment strategies remain unknown. Infectious etiologies should be considered, and corticosteroid treatments may hasten resolution of inflammatory findings. Continued treatment of affected patients with pegcetacoplan should be avoided.

10.
Curr Opin Struct Biol ; 83: 102730, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37992450

ABSTRACT

There is a clear need for developments in characterisation techniques that provide detailed information about structure-function relationships in biology. Using electron microscopy to achieve high resolution while maintaining a broad field of view remains a challenge, particularly for radiation-sensitive specimens where the signal-to-noise ratio required to maintain structural integrity is limited by low electron fluence. In this review, we explore the potential of cryogenic electron ptychography as an alternative method for characterising biological systems under low-fluence conditions. Using this method with increased information content from multiple sampled regions of interest potentially allows 3D reconstruction with far fewer particles than required in conventional cryo-electron microscopy. This is important for achieving higher resolution in systems where distributions of homogeneous single particles are difficult to obtain. We discuss the progress, limitations, and potential areas for future development of this approach for both single particle analysis and applications to heterogeneous large objects.


Subject(s)
Electrons , Single Molecule Imaging , Cryoelectron Microscopy/methods , Signal-To-Noise Ratio
11.
Ophthalmol Sci ; 3(4): 100394, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37885755

ABSTRACT

The rapid progress of large language models (LLMs) driving generative artificial intelligence applications heralds the potential of opportunities in health care. We conducted a review up to April 2023 on Google Scholar, Embase, MEDLINE, and Scopus using the following terms: "large language models," "generative artificial intelligence," "ophthalmology," "ChatGPT," and "eye," based on relevance to this review. From a clinical viewpoint specific to ophthalmologists, we explore from the different stakeholders' perspectives-including patients, physicians, and policymakers-the potential LLM applications in education, research, and clinical domains specific to ophthalmology. We also highlight the foreseeable challenges of LLM implementation into clinical practice, including the concerns of accuracy, interpretability, perpetuating bias, and data security. As LLMs continue to mature, it is essential for stakeholders to jointly establish standards for best practices to safeguard patient safety. Financial Disclosures: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

12.
J Vitreoretin Dis ; 7(5): 412-419, 2023.
Article in English | MEDLINE | ID: mdl-37706083

ABSTRACT

Purpose: We investigated the potential for indication bias to be present in previous studies of pentosan polysulfate sodium (PPS) pigmentary retinopathy by comparing the incidence and risk of retinopathy in patients with interstitial cystitis (IC) to matched controls. Methods: Adult women with IC from a multicenter database of electronic medical record data were matched to non-IC controls at a 1:4 ratio. The IC cohort was subdivided according to duration of PPS use: never, <5 years, and ≥5 years. Incidence and risk (estimated by Cox proportional hazards models) of retinopathy (defined by 6 International Classification of Diseases, Ninth and Tenth Revision codes) were compared between groups. Results: There were 22 060 women with IC and 88 240 women without IC. Average age was 53.92 years (SD, 16.22 years), and 96 110 (87.14%) patients were non-Hispanic White. Incidence of retinopathy per 100 000 person-years was 173.88 (95% CI, 162.78-185.53) for patients without IC, 226.63 (95% CI, 197.73-258.56) for IC without PPS use, 293.02 (95% CI 230.86-366.75) for IC with <5 years of PPS use, and 558.91 (95% CI, 399.29-761.07) for IC with ≥5 years of PPS use. Adjusted hazard ratios were 1.31 (95% CI, 1.13-1.51, P < .001) for IC without PPS use, 1.70 (95% CI, 1.35-2.15, P < .001) for IC with <5 years of PPS use, and 3.10 (95% CI, 2.26-4.27, P < .001) for IC with ≥5 years of PPS use. Conclusions: Patients with IC had greater incidence and risk of retinopathy. PPS use further increased the incidence and risk of retinopathy.

14.
Nat Commun ; 14(1): 3027, 2023 May 25.
Article in English | MEDLINE | ID: mdl-37230988

ABSTRACT

Advances in cryogenic transmission electron microscopy have revolutionised the determination of many macromolecular structures at atomic or near-atomic resolution. This method is based on conventional defocused phase contrast imaging. However, it has limitations of weaker contrast for small biological molecules embedded in vitreous ice, in comparison with cryo-ptychography, which shows increased contrast. Here we report a single-particle analysis based on the use of ptychographic reconstruction data, demonstrating that three dimensional reconstructions with a wide information transfer bandwidth can be recovered by Fourier domain synthesis. Our work suggests future applications in otherwise challenging single particle analyses, including small macromolecules and heterogeneous or flexible particles. In addition structure determination in situ within cells without the requirement for protein purification and expression may be possible.

15.
Diabetes Care ; 2023 Apr 26.
Article in English | MEDLINE | ID: mdl-37186032

ABSTRACT

OBJECTIVE: To simulate economic outcomes for individuals with diabetic macular edema (DME) and estimate the economic value of direct and indirect benefits associated with DME treatment. RESEARCH DESIGN AND METHODS: Our study pairs individual and cohort analyses to demonstrate the value of treatment for DME. We used a microsimulation model to simulate self-reported vision (SRV) and economic outcomes for individuals with DME. Four scenarios derived from clinical trial data were simulated and compared for a lifetime horizon: untreated, anti-VEGF therapy, laser, and steroid. To quantify the relative magnitude of costs and benefits of DME treatment in the U.S., we used a cohort-level analysis based on real-world treatment parameters derived from published data. RESULTS: In the model, excellent/good SRV roughly corresponded to 20/40 or better visual acuity. A representative 51-year-old treated for DME would spend 30-35% additional years with excellent/good SRV and 29-32% fewer years with fair/poor SRV relative to being untreated. A treated individual would experience 4-5% greater life expectancy and 9-13% more quality-adjusted life-years. Indirect benefits from treatment included 6-9% more years working, 12-19% greater lifetime earnings, and 8-16% fewer years with disability. For the U.S. DME cohort (1.1. million people), total direct benefit was $63.0 billion over 20 years, and total indirect benefit was $4.8 billion. Net value (benefit - cost) of treatment ranged from $28.1 billion to $52.8 billion. CONCLUSIONS: Treatment for DME provides economic value to patients and society through improved vision, life expectancy, and quality of life and indirectly through improved employment and disability outcomes.

17.
J Am Heart Assoc ; 12(9): e027920, 2023 05 02.
Article in English | MEDLINE | ID: mdl-37119076

ABSTRACT

Background Ectonucleotidases maintain vascular homeostasis by metabolizing extracellular nucleotides, modulating inflammation and thrombosis, and potentially, myocardial flow through adenosine generation. Evidence implicates dysfunction or deficiency of ectonucleotidases CD39 or CD73 in human disease; the utility of measuring levels of circulating ectonucleotidases as plasma biomarkers of coronary artery dysfunction or disease has not been previously reported. Methods and Results A total of 529 individuals undergoing clinically indicated positron emission tomography stress testing between 2015 and 2019 were enrolled in this single-center retrospective analysis. Baseline demographics, clinical data, nuclear stress test, and coronary artery calcium score variables were collected, as well as a blood sample. CD39 and CD73 levels were assessed as binary (detectable, undetectable) or continuous variables using ELISAs. Plasma CD39 was detectable in 24% of White and 8% of Black study participants (P=0.02). Of the clinical history variables examined, ectonucleotidase levels were most strongly associated with underlying liver disease and not other traditional coronary artery disease risk factors. Intriguingly, detection of circulating ectonucleotidase was inversely associated with stress myocardial blood flow (2.3±0.8 mL/min per g versus 2.7 mL/min per g±1.1 for detectable versus undetectable CD39 levels, P<0.001) and global myocardial flow reserve (Pearson correlation between myocardial flow reserve and log(CD73) -0.19, P<0.001). A subanalysis showed these differences held true independent of liver disease. Conclusions Vasodilatory adenosine is the expected product of local ectonucleotidase activity, yet these data support an inverse relationship between plasma ectonucleotidases, stress myocardial blood flow (CD39), and myocardial flow reserve (CD73). These findings support the conclusion that plasma levels of ectonucleotidases, which may be shed from the endothelial surface, contribute to reduced stress myocardial blood flow and myocardial flow reserve.


Subject(s)
Coronary Artery Disease , Myocardial Perfusion Imaging , Humans , Retrospective Studies , Tomography, X-Ray Computed , Adenosine , Coronary Vessels/diagnostic imaging , Perfusion , Myocardial Perfusion Imaging/methods , Coronary Artery Disease/diagnosis , Coronary Circulation
18.
Asia Pac J Ophthalmol (Phila) ; 12(2): 184-195, 2023.
Article in English | MEDLINE | ID: mdl-36728294

ABSTRACT

There have been recent advances in basic research and clinical studies in polypoidal choroidal vasculopathy (PCV). A recent, large-scale, population-based study found systemic factors, such as male gender and smoking, were associated with PCV, and a recent systematic review reported plasma C-reactive protein, a systemic biomarker, was associated with PCV. Growing evidence points to an association between pachydrusen, recently proposed extracellular deposits associated with the thick choroid, and the risk of development of PCV. Many recent studies on diagnosis of PCV have focused on applying criteria from noninvasive multimodal retinal imaging without requirement of indocyanine green angiography. There have been attempts to develop deep learning models, a recent subset of artificial intelligence, for detecting PCV from different types of retinal imaging modality. Some of these deep learning models were found to have high performance when they were trained and tested on color retinal images with corresponding images from optical coherence tomography. The treatment of PCV is either a combination therapy using verteporfin photodynamic therapy and anti-vascular endothelial growth factor (VEGF), or anti-VEGF monotherapy, often used with a treat-and-extend regimen. New anti-VEGF agents may provide more durable treatment with similar efficacy, compared with existing anti-VEGF agents. It is not known if they can induce greater closure of polypoidal lesions, in which case, combination therapy may still be a mainstay. Recent evidence supports long-term follow-up of patients with PCV after treatment for early detection of recurrence, particularly in patients with incomplete closure of polypoidal lesions.


Subject(s)
Angiogenesis Inhibitors , Choroid Diseases , Humans , Male , Angiogenesis Inhibitors/therapeutic use , Choroid/pathology , Polypoidal Choroidal Vasculopathy , Artificial Intelligence , Fluorescein Angiography/methods , Risk Factors , Tomography, Optical Coherence/methods , Retrospective Studies , Choroid Diseases/diagnosis , Choroid Diseases/therapy , Intravitreal Injections
19.
Cogn Sci ; 47(2): e13255, 2023 02.
Article in English | MEDLINE | ID: mdl-36807910

ABSTRACT

In cognitive science, there is a tacit norm that phenomena such as cultural variation or synaesthesia are worthy examples of cognitive diversity that contribute to a better understanding of cognition, but that other forms of cognitive diversity (e.g., autism, attention deficit hyperactivity disorder/ADHD, and dyslexia) are primarily interesting only as examples of deficit, dysfunction, or impairment. This status quo is dehumanizing and holds back much-needed research. In contrast, the neurodiversity paradigm argues that such experiences are not necessarily deficits but rather are natural reflections of biodiversity. Here, we propose that neurodiversity is an important topic for future research in cognitive science. We discuss why cognitive science has thus far failed to engage with neurodiversity, why this gap presents both ethical and scientific challenges for the field, and, crucially, why cognitive science will produce better theories of human cognition if the field engages with neurodiversity in the same way that it values other forms of cognitive diversity. Doing so will not only empower marginalized researchers but will also present an opportunity for cognitive science to benefit from the unique contributions of neurodivergent researchers and communities.


Subject(s)
Attention Deficit Disorder with Hyperactivity , Cognition , Humans , Attention Deficit Disorder with Hyperactivity/psychology , Cognitive Science
20.
ACS Phys Chem Au ; 3(1): 63-73, 2023 Jan 25.
Article in English | MEDLINE | ID: mdl-36718260

ABSTRACT

Tryptophan is one of few residues that participates in biological electron transfer reactions. Upon substitution of the native Cu2+ center with Zn2+ in the blue-copper protein azurin, a long-lived tryptophan neutral radical can be photogenerated. We report the following quantum yield values for Zn-substituted azurin in the presence of the electron acceptor Cu(II)-azurin: formation of the tryptophan neutral radical (Φrad), electron transfer (ΦET), fluorescence (Φfluo), and phosphorescence (Φphos), as well as the efficiency of proton transfer of the cation radical (ΦPT). Increasing the concentration of the electron acceptor increased Φrad and ΦET values and decreased Φphos without affecting Φfluo. At all concentrations of the acceptor, the value of ΦPT was nearly unity. These observations indicate that the phosphorescent triplet state is the parent state of electron transfer and that nearly all electron transfer events lead to proton loss. Similar results regarding the parent state were obtained with a different electron acceptor, [Co(NH3)5Cl]2+; however, Stern-Volmer graphs revealed that [Co(NH3)5Cl]2+ was a more effective phosphorescence quencher (K SV = 230 000 M-1) compared to Cu(II)-azurin (K SV = 88 000 M-1). Competition experiments in the presence of both [Co(NH3)5Cl]2+ and Cu(II)-azurin suggested that [Co(NH3)5Cl]2+ is the preferred electron acceptor. Implications of these results in terms of quenching mechanisms are discussed.

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