Pursuit and escape drive fine-scale movement variation during migration in a temperate alpine ungulate.

Climate change reduces snowpack, advances snowmelt phenology, drives summer warming, alters growing season precipitation regimes, and consequently modifies vegetation phenology in mountain systems. Elevational migrants track spatial variation in seasonal plant growth by moving between ranges at different elevations during spring, so climate-driven vegetation change may disrupt historic benefits of migration. Elevational migrants can furthermore cope with short-term environmental variability by undertaking brief vertical movements to refugia when sudden adverse conditions arise. We uncover drivers of fine-scale vertical movement variation during upland migration in an endangered alpine specialist, Sierra Nevada bighorn sheep (Ovis canadensis sierrae) using a 20-year study of GPS collar data collected from 311 unique individuals. We used integrated step-selection analysis to determine factors that promote vertical movements and drive selection of destinations following vertical movements. Our results reveal that relatively high temperatures consistently drive uphill movements, while precipitation likely drives downhill movements. Furthermore, bighorn select destinations at their peak annual biomass and maximal time since snowmelt. These results indicate that although Sierra Nevada bighorn sheep seek out foraging opportunities related to landscape phenology, they compensate for short-term environmental stressors by undertaking brief up- and downslope vertical movements. Migrants may therefore be impacted by future warming and increased storm frequency or intensity, with shifts in annual migration timing, and fine-scale vertical movement responses to environmental variability.

Brief research report: ETS-1 blockade increases ICAM-1 expression in activated human retinal endothelial cells.

Intercellular adhesion molecule 1 (ICAM-1) is a central cell adhesion molecule for retinal transendothelial migration of the leukocytes in non-infectious posterior uveitis. Inhibiting ICAM1 gene transcription reduces induction of ICAM-1 in inflamed retinal endothelium. Based on published literature implicating transcription factor ETS-1 as an activator of ICAM1 gene transcription, we investigated the effect of ETS-1 blockade on ICAM-1 levels in cytokine-stimulated human retinal endothelial cells. We first examined ICAM1 and ETS1 transcript expression in human retinal endothelial cells exposed to tumor necrosis factor-alpha (TNF-α) or interleukin-1beta (IL-1ß). ICAM1 and ETS1 transcripts were increased in parallel in primary human retinal endothelial cell isolates (n = 5) after a 4-hour stimulation with TNF-α or IL-1ß (p ≤ 0.012 and ≤ 0.032, respectively). We then assessed the effect of ETS-1 blockade by small interfering (si)RNA on cellular ICAM1 transcript and membrane-bound ICAM-1 protein. ETS1 transcript was reduced by greater than 90% in cytokine-stimulated and non-stimulated human retinal endothelial cell monolayers following a 48-hour treatment with two ETS-1-targeted siRNA, in comparison to negative control non-targeted siRNA (p ≤ 0.0002). The ETS-1 blockade did not reduce ICAM1 transcript expression nor levels of membrane-bound ICAM-1 protein, rather it increased both for a majority of siRNA-treatment and cytokine-stimulation conditions (p ≤ 0.018 and ≤ 0.004, respectively). These unexpected findings indicate that ETS-1 blockade increases ICAM-1 transcript and protein levels in human retinal endothelial cells. Thus ETS-1-targeting would be expected to promote rather than inhibit retinal transendothelial migration of leukocytes in non-infectious posterior uveitis.

Influence of gender on clinical presentation, management practices and outcomes of ocular syphilis.

Ocular syphilis is a re-emerging inflammatory eye disease with a clear gender imbalance, disproportionately affecting men. We investigated the impact of gender on the presentation, management practices and clinical outcomes of this condition. Data generated from a study of patients consecutively diagnosed with ocular syphilis who attended a subspecialist uveitis service at one of four hospitals in Brazil over a 30-month period were disaggregated for analysis by gender. Two-hundred and fourteen eyes (161 men and 53 women) of 127 patients (96 men and 31 women) were included. Posterior uveitis was the most common presentation in both men and women (80.1% vs. 66.7%, p > 0.05), but men were significantly more likely to have vitritis as a feature of their disease (49.4% versus 28.8%, p = 0.019). Three eyes of women had nodular anterior scleritis (p = 0.015). Men were more likely to undergo a lumbar puncture to assess for neurosyphilis (71.9% vs. 51.6%, p = 0.048), but men and women undergoing a lumbar puncture were equally likely to have a cerebrospinal fluid abnormality (36.2% vs. 25.0%, p = 0.393). All patients were treated with aqueous penicillin G or ceftriaxone, and there was a trend towards more men receiving adjunctive systemic corticosteroid treatment as part of their management (65.2% vs. 46.7%, p = 0.071). There were no significant differences in the age of presentation, bilaterality of disease, anatomical classification of uveitis, initial or final visual acuity, and rates of ocular complications between men and women. Our findings indicate that ocular syphilis has comparable outcomes in men and women, but that there are differences in the type of ocular inflammation and management practices between the genders.

Ocular manifestations of COVID-19.

There is an increasing body of knowledge regarding how COVID-19 may be associated with ocular disease of varying severity and duration. This article discusses the literature on the ocular manifestations associated with COVID-19, including appraisal of the current evidence, suggested mechanisms of action, associated comorbidities and risk factors, timing from initial infection to diagnosis and clinical red flags. The current literature primarily comprises case reports and case series which inevitably lack control groups and evidence to support causality. However, these early data have prompted the development of larger population-based and laboratory studies that are emerging. As new data become available, a better appraisal of the true effects of COVID-19 on the eye will be possible. While the COVID-19 pandemic was officially declared no longer a "global health emergency" by the World Health Organization (WHO) in May 2023, case numbers continue to rise. Reinfection with different variants is predicted to lead to a growing cumulative burden of disease, particularly as more chronic, multi-organ sequelae become apparent with potentially significant ocular implications. COVID-19 ocular manifestations are postulated to be due to three main mechanisms: firstly, there is a dysregulated immune response to the initial infection linked to inflammatory eye disease; secondly, patients with COVID-19 have a greater tendency towards a hypercoagulable state, leading to prothrombotic events; thirdly, patients with severe COVID-19 requiring hospitalisation and are immunosuppressed due to administered corticosteroids or comorbidities such as diabetes mellitus are at an increased risk of secondary infections, including endophthalmitis and rhino-orbital-mucormycosis. Reported ophthalmic associations with COVID-19, therefore, include a range of conditions such as conjunctivitis, scleritis, uveitis, endogenous endophthalmitis, corneal graft rejection, retinal artery and vein occlusion, non-arteritic ischaemic optic neuropathy, glaucoma, neurological and orbital sequelae. With the need to consider telemedicine consultation in view of COVID-19's infectivity, understanding the range of ocular conditions that may present during or following infection is essential to ensure patients are appropriately triaged, with prompt in-person ocular examination for management of potentially sight-threatening and life-threatening diseases.

Syphilitic scleritis and episcleritis: A review.

Scleritis and episcleritis are rare, but potentially sight-threatening forms of syphilis. To provide a full description of this neglected subset of ocular syphilis, we evaluated the English literature for reports of syphilitic scleritis and episcleritis, recording the demographics, clinical characteristics, serological data, management practices, treatment responses, and visual outcomes. Previously published descriptions of 44 patients with syphilitic scleritis (50 eyes) and 9 patients with syphilitic episcleritis (14 eyes) were identified. The predominant type of scleritis was anterior scleritis, accounting for 92.9% of cases, with nodular anterior scleritis being the most frequent subtype at 58.1%. Almost one-quarter of patients were co-infected with human immunodeficiency virus (HIV). Initial misdiagnosis was common and led to delays in initiating treatment with appropriate antibiotics. Visual outcomes were often good in both scleritis and episcleritis, irrespective of HIV infection status, although complications including scleral thinning, keratitis, and uveitis, along with permanent visual loss and an association with neurosyphilis, were reported. Response to antibiotic treatment was typically rapid, often within 1 week. With the rising global incidence of syphilis, testing patients with scleritis or episcleritis for this infectious disease is important to ensure prompt diagnosis and treatment for best ocular and systemic outcomes.

Treatment of Noninfectious Uveitic Macular Edema with Periocular and Intraocular Corticosteroid Therapies: A Report by the American Academy of Ophthalmology.

PURPOSE: To review the evidence on the effectiveness and complications of periocular and intraocular corticosteroid therapies for noninfectious uveitic macular edema. METHODS: A literature search of the PubMed database was conducted last in December 2021 and a post-assessment search was conducted in March 2023. The searches were limited to articles published in English and no date restrictions were imposed. The combined searches yielded 739 citations; 53 articles were selected for inclusion because the studies (1) evaluated periocular corticosteroid injection, intraocular corticosteroid injection or implant, suprachoroidal corticosteroid injection, or a combination thereof for uveitic macular edema; (2) had outcomes that included visual acuity (VA) or macular edema assessed clinically or imaged by OCT or fluorescein angiography; and (3) included more than 20 patients. RESULTS: This assessment reviewed 23 articles that provided level I or level II evidence from 18 studies on the use of periocular, suprachoroidal, and intravitreal triamcinolone acetonide injections and intravitreal dexamethasone and fluocinolone acetonide implants or inserts in noninfectious uveitic macular edema. These reports consistently demonstrated that all investigated periocular and intraocular corticosteroid therapies improved VA, macular structure, or both. One comparative study showed that intravitreal triamcinolone acetonide injection and the dexamethasone intravitreal implant had effectiveness superior to that of periocular triamcinolone acetonide injection for these outcomes. As a group, the studies highlighted the potential for these therapies to elevate intraocular pressure and to accelerate cataract formation. CONCLUSIONS: The published literature provides high-quality evidence that periocular and intraocular corticosteroid therapies are effective and safe for the treatment of noninfectious uveitic macular edema. However, information on the relative effectiveness and complication rates across the different therapies is limited. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Effectiveness of Conventional Digital Fundus Photography-Based Teleretinal Screening for Diabetic Retinopathy and Diabetic Macular Edema: A Report by the American Academy of Ophthalmology.

PURPOSE: This American Academy of Ophthalmology Ophthalmic Technology Assessment aims to assess the effectiveness of conventional teleretinal screening (TS) in detecting diabetic retinopathy (DR) and diabetic macular edema (DME). METHODS: A literature search of the PubMed database was conducted most recently in July 2023 to identify data published between 2006 and 2023 on any of the following elements related to TS effectiveness: (1) the accuracy of TS in detecting DR or DME compared with traditional ophthalmic screening with dilated fundus examination or 7-standard field Early Treatment Diabetic Retinopathy Study photography, (2) the impact of TS on DR screening compliance rates or other patient behaviors, and (3) cost-effectiveness and patient satisfaction of TS compared with traditional DR screening. Identified studies then were rated based on the Oxford Centre for Evidence-Based Medicine grading system. RESULTS: Eight level I studies, 14 level II studies, and 2 level III studies were identified in total. Although cross-study comparison is challenging because of differences in reference standards and grading methods, TS demonstrated acceptable sensitivity and good specificity in detecting DR; moderate to good agreement between TS and reference-standard DR grading was observed. Performance of TS was not as robust in detecting DME, although the number of studies evaluating DME specifically was limited. Two level I studies, 5 level II studies, and 1 level III study supported that TS had a positive impact on overall DR screening compliance, even increasing it by more than 2-fold in one study. Studies assessing cost-effectiveness and patient satisfaction were not graded formally, but they generally showed that TS was cost-effective and preferred by patients over traditional surveillance. CONCLUSIONS: Conventional TS is an effective approach to DR screening not only for its accuracy in detecting referable-level disease, but also for improving screening compliance in a cost-effective manner that may be preferred by patients. Further research is needed to elucidate the ideal approach of TS that may involve integration of artificial intelligence or other imaging technologies in the future. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Metabolic reprogramming of the retinal pigment epithelium by cytokines associated with age-related macular degeneration.

The complex metabolic relationship between the retinal pigment epithelium (RPE) and photoreceptors is essential for maintaining retinal health. Recent evidence indicates the RPE acts as an adjacent lactate sink, suppressing glycolysis in the epithelium in order to maximize glycolysis in the photoreceptors. Dysregulated metabolism within the RPE has been implicated in the pathogenesis of age-related macular degeneration (AMD), a leading cause of vision loss. In the present study, we investigate the effects of four cytokines associated with AMD, TNFα, TGF-ß2, IL-6, and IL-1ß, as well as a cocktail containing all four cytokines, on RPE metabolism using ARPE-19 cells, primary human RPE cells, and ex vivo rat eyecups. Strikingly, we found cytokine-specific changes in numerous metabolic markers including lactate production, glucose consumption, extracellular acidification rate, and oxygen consumption rate accompanied by increases in total mitochondrial volume and ATP production. Together, all four cytokines could potently override the constitutive suppression of glycolysis in the RPE, through a mechanism independent of PI3K/AKT, MEK/ERK, or NF-κB. Finally, we observed changes in glycolytic gene expression with cytokine treatment, including in lactate dehydrogenase subunit and glucose transporter expression. Our findings provide new insights into the metabolic changes in the RPE under inflammatory conditions and highlight potential therapeutic targets for AMD.

Systemic and Ocular Manifestations of Arboviral Infections: A Review.

PURPOSE: To provide an overview of pre-selected emerging arboviruses (arthropod-borne viruses) that cause ocular inflammation in humans. METHODS: A comprehensive review of the literature published between 1997 and 2023 was conducted in PubMed database. We describe current insights into epidemiology, systemic and ocular manifestations, diagnosis, treatment, and prognosis of arboviral diseases including West Nile fever, Dengue fever, Chikungunya, Rift Valley fever, Zika, and Yellow fever. RESULTS: Arboviruses refer to a group of ribonucleic acid viruses transmitted to humans by the bite of hematophagous arthropods, mainly mosquitoes. They mostly circulate in tropical and subtropical zones and pose important public health challenges worldwide because of rising incidence, expanding geographic range, and occurrence of prominent outbreaks as a result of climate change, travel, and globalization. The clinical signs associated with infection from these arboviruses are often inapparent, mild, or non-specific, but they may include serious, potentially disabling or life-threatening complications. A wide spectrum of ophthalmic manifestations has been described including conjunctival involvement, anterior uveitis, intermediate uveitis, various forms of posterior uveitis, maculopathy, optic neuropathy, and other neuro-ophthalmic manifestations. Diagnosis of arboviral diseases is confirmed with either real time polymerase chain reaction or serology. Management involves supportive care as there are currently no specific antiviral drug options. Corticosteroids are often used for the treatment of associated ocular inflammation. Most patients have a good visual prognosis, but there may be permanent visual impairment due to ocular structural complications in some. Community-based integrated mosquito management programs and personal protection measures against mosquito bites are the best ways to prevent human infection and disease. CONCLUSION: Emerging arboviral diseases should be considered in the differential diagnosis of ocular inflammatory conditions in patients living in or returning from endemic regions. Early clinical consideration followed by confirmatory testing can limit or prevent unnecessary treatments for non-arboviral causes of ocular inflammation. Prevention of these infections is crucial.

Characterisation of social media conversations on syphilis: an unobtrusive observational study.

BACKGROUND: Conversations around disease conducted through social media provide a means for capturing public perspectives that may be useful in considering public health approaches. Syphilis is a sexually transmitted disease that is re-emerging. We sought to characterise online discourse on syphilis using data collected from the social media platform, Twitter. METHODS: We extracted English-language tweets containing the word 'syphilis' posted on Twitter in 2019. Tweet identification number and URL, date and time of posting, number of retweets and likes, and the author's screen name, username and biographical statement were included in the dataset. A systematically sampled 10% subset of the data was subjected to qualitative analysis, involving categorisation on content. All tweets assigned to the category of medical resource were assessed for clinical accuracy. The engagement ratio for each category was calculated as (retweets+likes):tweets. RESULTS: In 2019, 111,388 tweets mentioning syphilis were posted by 69,921 authors. The most frequent content category - totalling 5370 tweets (48%) - was a joke. Of 1762 tweets (16%) categorised as a medical resource, 1484 (84%) were medically correct and 240 (14%) were medically incorrect; for 38 (2%), medical accuracy could not be judged from the information posted. Tweets categorised as personal experiences had the highest engagement ratio at approximately 19:1. Medical resource tweets had an engagement ratio of approximately 7:1. CONCLUSIONS: We found medical information about syphilis was limited on Twitter. As tweets about personal experiences generate high engagement, coupling an experience with information may provide opportunity for public health education.

The Infectious Uveitis Treatment Algorithm Network (TITAN) Report 1-global current practice patterns for the management of Herpes Simplex Virus and Varicella Zoster Virus anterior uveitis.

AIMS: To present current expert practice patterns and to formulate a consensus for the management of HSV and VZV AU by uveitis specialists worldwide. METHODS: A two-round online modified Delphi survey with masking of the study team was conducted. Responses were collected from 76 international uveitis experts from 21 countries. Current practices in the diagnosis and treatment of HSV and VZV AU were identified. A working group (The Infectious Uveitis Treatment Algorithm Network [TITAN]) developed data into consensus guidelines. Consensus is defined as a particular response towards a specific question meeting ≥75% of agreement or IQR ≤ 1 when a Likert scale is used. RESULTS: Unilaterality, increased intraocular pressure (IOP), decreased corneal sensation and diffuse or sectoral iris atrophy are quite specific for HSV or VZV AU from consensus opinion. Sectoral iris atrophy is characteristic of HSV AU. Treatment initiation is highly variable, but most experts preferred valacyclovir owing to simpler dosing. Topical corticosteroids and beta-blockers should be used if necessary. Resolution of inflammation and normalisation of IOP are clinical endpoints. CONCLUSIONS: Consensus was reached on several aspects of diagnosis, choice of initial treatment, and treatment endpoints for HSV and VZV AU. Treatment duration and management of recurrences varied between experts.

The Infectious Uveitis Treatment Algorithm Network (TITAN) Report 2-global current practice patterns for the management of Cytomegalovirus anterior uveitis.

AIMS: To present current practice patterns in the diagnosis and management of Cytomegalovirus anterior uveitis (CMV AU) by uveitis experts worldwide. METHODS: A two-round modified Delphi survey with masking of the study team was performed. Based on experience and expertise, 100 international uveitis specialists from 21 countries were invited to participate in the survey. Variation in the diagnostic approaches and preferred management of CMV AU was captured using an online survey platform. RESULTS: Seventy-five experts completed both surveys. Fifty-five of the 75 experts (73.3%) would always perform diagnostic aqueous tap in suspected CMV AU cases. Consensus was achieved for starting topical antiviral treatment (85% of experts). About half of the experts (48%) would only commence systemic antiviral treatment for severe, prolonged, or atypical presentation. The preferred specific route was ganciclovir gel 0.15% for topical treatment (selected by 70% of experts) and oral valganciclovir for systemic treatment (78% of experts). The majority of experts (77%) would commence treatment with topical corticosteroid four times daily for one to two weeks along with antiviral coverage, with subsequent adjustment depending on the clinical response. Prednisolone acetate 1% was the drug of choice (opted by 70% of experts). Long-term maintenance treatment (up to 12 months) can be considered for chronic course of inflammation (88% of experts) and those with at least 2 episodes of CMV AU within a year (75-88% of experts). CONCLUSIONS: Preferred management practices for CMV AU vary widely. Further research is necessary to refine diagnosis and management and provide higher-level evidence.

Effects of tumor necrosis factor-α and interleukin-1ß on human retinal endothelial cells.

Uveitis, or intraocular inflammation, is a potentially blinding condition that mostly affects the working-age population. The cytokines, tumor necrosis factor (TNF)-α and interleukin (IL)-1ß, play a role in the pathogenesis of non-infectious uveitis and have been linked to the breakdown of the inner blood-retinal barrier, composed mainly of retinal endothelial cells, leading to macular oedema and vascular leakage. However, the effects of TNF-α and IL-1ß on human retinal endothelial function are not fully understood. In this work, we investigated the impact of TNF-α and IL-1ß on several aspects of human retinal endothelial cell biology. Through a real-time biosensor, the impact of TNF-α and IL-1ß on formation of a retinal endothelial cell barrier was analyzed. Changes in junctional components were assessed via RT-qPCR and immunolabelling. Cell survival, necrosis and apoptosis were appraised via cell proliferation and flow cytometric studies. Tumor necrosis factor-α and IL-1ß impaired the electrical resistance of the retinal endothelial cell barrier, while the addition of a potentially barrier-impairing cytokine, IL-6, did not enhance the effect of TNF-α and IL-1ß. Level of the gene transcript encoding zonula occludens (ZO)-1 was diminished, while ZO-1 protein configuration was changed by TNF-α and IL-1ß. Both cytokines affected human retinal endothelial cell proliferation and viability, while only TNF-α increased rates of necrosis. These results indicate that TNF-α and IL-1ß are important drivers of retinal endothelial dysfunction in non-infectious uveitis, suggesting that targeting these cytokines is critical when treating complications of uveitis, such as macular oedema and vascular leakage.

Inflammatory cytokines as mediators of retinal endothelial barrier dysfunction in non-infectious uveitis.

Characterised by intraocular inflammation, non-infectious uveitis includes a large group of autoimmune and autoinflammatory diseases that either involve the eye alone or have both ocular and systemic manifestations. When non-infectious uveitis involves the posterior segment of the eye, specifically the retina, there is substantial risk of vision loss, often linked to breakdown of the inner blood-retinal barrier. This barrier is formed by non-fenestrated retinal vascular endothelial cells, reinforced by supporting cells that include pericytes, Müller cells and astrocytes. Across the published literature, a group of inflammatory cytokines stand out as prominent mediators of intraocular inflammation, with effects on the retinal endothelium that may contribute to breakdown of the inner blood-retinal barrier, namely tumour necrosis factor (TNF)-α, interleukin (IL)-1ß, IL-6, IL-8, IL-17 and chemokine C-C motif ligand (CCL)2. This article reviews the function of each cytokine and discusses the evidence for their involvement in retinal endothelial barrier dysfunction in non-infectious uveitis, including basic laboratory investigations, studies of ocular fluids collected from patients with non-infectious uveitis, and results of clinical treatment trials. The review also outlines gaps in knowledge in this area. Understanding the disease processes at a molecular level can suggest treatment alternatives that are directed against appropriate biological targets to protect the posterior segment of eye and preserve vision in non-infectious uveitis.

Sarcoid Uveitis in Children.

Sarcoidosis is a multi-system granulomatous disease that often presents with uveitis. Although sarcoidosis and sarcoid uveitis typically occur in adulthood, children also may be affected. There are two distinct clinical presentations of the pediatric disease, associated with younger and older age groups, and having different causations. "Early-onset sarcoidosis", beginning at age 5 years or less, is an autosomal dominant genetic disease, caused by a mutation in the NOD2 gene. It is also known as sporadic Blau syndrome or Jabs syndrome. "Adult-type sarcoidosis", usually beginning between the ages of 8 and 15 years, is believed to represent an excessive response to an environmental antigen. There is limited literature on the management of pediatric sarcoidosis, and treatment follows an approach applied to other forms of pediatric non-infectious uveitis. When systemic immunomodulatory therapy is indicated, methotrexate and/or adalimumab are often employed. The condition may persist into adulthood, and thus long-term follow-up is indicated.

Vision-related quality of life in patients treated for ocular syphilis.

Multiple studies have showed negative impact of non-infectious uveitis on quality of life (QoL). Less is understood regarding life experiences in patients with infectious uveitis. We investigated vision-related QoL in individuals who had recovered from ocular syphilis. 32 adults treated for ocular syphilis at a uveitis service in Brazil completed the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25), and a comprehensive ophthalmic examination was performed. Medical records were reviewed to confirm resolution of ocular inflammation for 3 months pre-enrolment, and collect clinical data. The NEI VFQ-25 composite score was low overall (75.5 ± 19.8, mean ± standard deviation), and subscale scores varied from relative lows of 59.1 ± 39.6 (driving) and 60.9 ± 24.5 (mental health), to relative highs of 84.8 ± 21.8 (ocular) and 89.1 ± 21.0 (color vision). Adults aged over 40 years and those with a final visual acuity of 20/50 or worse had significantly lower mean composite and subscale scores. Other clinical characteristics-including gender, HIV co-infection, and type of uveitis-did not significantly influence scores. Our findings, taken in context with previous observations that prompt recognition achieves better vision outcomes, suggest early treatment may improve QoL after recovery from ocular syphilis.

Oxidative Stress and Its Regulation in Diabetic Retinopathy.

Diabetic retinopathy is the retinal disease associated with hyperglycemia in patients who suffer from type 1 or type 2 diabetes. It includes maculopathy, involving the central retina and characterized by ischemia and/or edema, and peripheral retinopathy that progresses to a proliferative stage with neovascularization. Approximately 10% of the global population is estimated to suffer from diabetes, and around one in 5 of these individuals have diabetic retinopathy. One of the major effects of hyperglycemia is oxidative stress, the pathological state in which elevated production of reactive oxygen species damages tissues, cells, and macromolecules. The retina is relatively prone to oxidative stress due to its high metabolic activity. This review provides a summary of the role of oxidative stress in diabetic retinopathy, including a description of the retinal cell players and the molecular mechanisms. It discusses pathological processes, including the formation and effects of advanced glycation end-products, the impact of metabolic memory, and involvements of non-coding RNA. The opportunities for the therapeutic blockade of oxidative stress in diabetic retinopathy are also considered.

Anthropogenic activities and age class mediate carnivore habitat selection in a human-dominated landscape.

Human activities increasingly challenge wild animal populations by disrupting ecological connectivity and population persistence. Yet, human-modified habitats can provide resources, resulting in selection of disturbed areas by generalist species. To investigate spatial and temporal responses of a generalist carnivore to human disturbance, we investigated habitat selection and diel activity patterns in caracals (Caracal caracal). We GPS-collared 25 adults and subadults in urban and wildland-dominated subregions in Cape Town, South Africa. Selection responses for landscape variables were dependent on subregion, animal age class, and diel period. Contrary to expectations, caracals did not become more nocturnal in urban areas. Caracals increased their selection for proximity to urban areas as the proportion of urban area increased. Differences in habitat selection between urban and wildland caracals suggest that individuals of this generalist species exhibit high behavioral flexibility in response to anthropogenic disturbances that emerge as a function of habitat context.