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Dennis Nkanga,1 Olukorede Adenuga,2 Ogugua Okonkwo,3 Wilson Ovienria,4 Affiong Ibanga,1 Chineze Agweye,1 Idris Oyekunle,3 Toyin Akanbi3 On behalf of The Collaborative Retina Research Network1University of Calabar Teaching Hospital, Calabar, Nigeria; 2Jos University Teaching Hospital, Jos, Nigeria; 3Eye Foundation Hospital, Lagos, Nigeria; 4Irrua Specialist Hospital, Edo, NigeriaCorrespondence: Ogugua OkonkwoEye Foundation Hospital, 27 Isaac John Street, GRA. Ikeja, Lagos, NigeriaTel +234 8035027308Email o_okonkwo@yahoo.comPurpose: To determine the burden of retinal diseases and the degree of visual impairment associated with each disease, amongst Nigerians.Patients and Methods: This was a hospital-based multicenter, prospective, cross-sectional, non-comparative study conducted from January to December 2018. Data was obtained from consecutive patients with a retinal diagnosis presenting at the general ophthalmic and specialty retina clinics in four hospitals (three public, and one private teaching eye department) in Nigeria. Biodata, visual acuity and refraction, intraocular pressure, findings on dilated retinal examination, diagnosis and systemic diseases were noted. Degree of monocular and bilateral visual loss associated with each diagnosed retinal disease was summarized and p value was calculated using chi-square test. P < 0.05 was considered significant.Results: Eight hundred seventy-six of 8614 patients had a retinal diagnosis; establishing a hospital-based retinal disease prevalence of 9.8%. Male:female ratio was 1.1:1. The mean age of study patients was 49.97 (standard deviation 17.64 years). Mean symptom duration was 21.63 months (standard deviation 41.94). The mean intraocular pressure was 13.87 mmHg. Forty-three different retinal diseases were diagnosed. The most common was retinal complications of diabetes, i.e., diabetic retinopathy (DR) alone, diabetic macular edema (DME) alone and a combination of DR and DME, which accounted for 13.7%, 5.6% and 9.3%, respectively (contributed 28.6% of the entire diagnosis). This was followed by retinal detachment (RD), in 219 eyes (15.4%), dry age-related macular degeneration (AMD) in 124 eyes (8.7%). Nearly half of the eyes were blind or severely visually impaired. Blindness occurred in 34.1% of eyes; severe visual impairment in 8.2% of eyes and 29.7% had normal vision. There were 469 patients who had systemic diseases. The common systemic diseases were hypertension in 169 patients (19.3% of the total number of patients), hypertension and diabetes in 156 patients (18%), and diabetes alone in 98 patients (11.1%). Sickle cell disease was present in 1.5%.Conclusion: There is need to invest in infrastructure, local training and development of systems for early detection and treatment of several retinal diseases in sub-Saharan Africa; DR and DME having the largest burden. Collaborative physician care and management of hypertension and diabetes could significantly reduce the burden of DR and DME.Keywords: vitreoretinal diseases, sub-Saharan Africa, diabetic retinopathy, macular edema, retinal detachment

BackgroundPrior studies of Alzheimer's disease (AD) biomarker disclosure have answered important questions about individuals' safety after learning and comprehending their amyloid PET results; however, these studies have typically employed highly structured disclosure protocols and focused on the psychological impact of disclosure (e.g., anxiety, depression, and suicidality) in homogeneous populations. More work is needed to develop flexible disclosure protocols and study outcomes in ethnoculturally representative samples.MethodsThe Alzheimer's Disease Neuroimaging Initiative (ADNI) is formally incorporating amyloid PET disclosure into the newest protocol (ADNI-4). Participants across the cognitive spectrum who wish to know their amyloid PET results may learn them. The pragmatic disclosure process spans four timepoints: (1) a pre-disclosure visit, (2) the PET scan and its read, (3) a disclosure visit, and (4) a post-disclosure check-in. This process applies to all participants, with slight modifications to account for their cognitive status. In designing this process, special emphasis was placed on utilizing investigator discretion. Participant measures include perceived risk of dementia, purpose in life, and disclosure satisfaction. Investigator assessment of the disclosure visit (e.g., challenges encountered, topics discussed, etc.) is also included.ResultsData collection is ongoing. Results will allow for more robust characterization of the impact of learning amyloid PET results on individuals and describe the perspectives of investigators.ConclusionThe pragmatic design of the disclosure process in ADNI-4 coupled with the novel participant and investigator data will inform future disclosure practices. This is especially important as disclosure of biomarker results expands in research and care.

The process of identifying suitable genome-wide association (GWA) studies and formatting the data to calculate multiple polygenic risk scores on a single genome can be laborious. Here, we present a centralized polygenic risk score calculator currently containing over 250,000 genetic variant associations from the NHGRI-EBI GWAS Catalog for users to easily calculate sample-specific polygenic risk scores with comparable results to other available tools. Polygenic risk scores are calculated either online through the Polygenic Risk Score Knowledge Base (PRSKB; https://prs.byu.edu ) or via a command-line interface. We report study-specific polygenic risk scores across the UK Biobank, 1000 Genomes, and the Alzheimer's Disease Neuroimaging Initiative (ADNI), contextualize computed scores, and identify potentially confounding genetic risk factors in ADNI. We introduce a streamlined analysis tool and web interface to calculate and contextualize polygenic risk scores across various studies, which we anticipate will facilitate a wider adaptation of polygenic risk scores in future disease research.

Objective: Endoscopic endonasal surgery is a minimally invasive technique that has revolutionised the management of complex neurosurgical, otolaryngological, skull-base and craniofacial lesions. Traditionally performed under general anaesthetic, this study explores the growing role of local anaesthetic techniques. Method: A contemporaneous review of modified dental techniques and intraoral anatomy provides a supportive guide for performing endoscopic sinus surgery under local anaesthetic. Results: The practical procedures for four midfacial nerve blocks are described with relevance to endoscopic surgery under local anaesthetic. Anatomy, surgical technique and potential complications are discussed for the incisive foramen block, sphenopalatine ganglion block (via endonasal approach), maxillary nerve block (via the greater palatine foramen and the transoral lateral pterygoid plate approach) and transcutaneous approach to the pterygomaxillary fissure. Conclusion: Ultimately, such techniques may extend the safety and efficacy of endoscopic sinus surgery, limit surgical risk and increase satisfaction for patients, surgeons and healthcare managers alike. [ABSTRACT FROM AUTHOR]

Ogugua Ndubuisi Okonkwo,1 Chineze Thelma Agweye,2 Toyin Akanbi1 1Department of Ophthalmology, Eye Foundation Hospital and Eye Foundation Retina Institute, Ikeja, Lagos, Nigeria; 2Department of Ophthalmology, University of Calabar and University of Calabar Teaching Hospital, Cross River, NigeriaCorrespondence: Ogugua Ndubuisi Okonkwo, Eye Foundation Retina Institute, 27, Isaac John Street, GRA, Ikeja, Lagos, Nigeria, Tel +234 803 502 7308, Email o_okonkwo@yahoo.comAbstract: Nonarteritic central retinal artery occlusion (NA-CRAO) is a variant of acute ischemic stroke (AIS) and is a cause of sudden severe loss of vision. There are guidelines by the American Heart Association and the American Stroke Association for the care of CRAO patients. This review explores the basis of retinal neuroprotection for CRAO and its potential for improving the outcome of NA-CRAO. Recently, there have been significant advances in research into the use of neuroprotection to treat retinal diseases, including retinal detachment, age-related macular degeneration, and inherited retinal diseases. Also, neuroprotective research in AIS has been extensive, and newer drugs tested, including Uric acid, Nerinetide, and Otaplimastat, with promising results. Progress in cerebral neuroprotection after AIS offers hope for retinal neuroprotection after CRAO; and a possibility of extrapolating research findings from AIS into CRAO. Combining neuroprotection and thrombolysis can extend the therapeutic window for NA-CRAO treatment and potentially improve outcomes. Experimented neuroprotection for CRAO includes Angiopoietin (Comp Ang1), KUS 121, Gene therapy (XIAP), and hypothermia. Efforts in the field of neuroprotection for NA-CRAO should focus on better imaging to delineate the penumbra after an acute episode of NA-CRAO (using a combination of high-definition optical coherence angiography and electrophysiology). Also, research should explore details of pathophysiologic mechanisms involved in NA-CRAO, allowing for further neuroprotective intervention, and closing the gap between preclinical and clinical neuroprotection.Keywords: neuroprotection, non-arteritic central retinal artery occlusion, thrombolysis, acute ischemic stroke

Concentrations of poly- and perfluorinated substances (PFASs) were determined in Hartbeespoort and Roodeplaat Dams, South Africa. Water samples were collected from the dams in February-March, and May-June, representing southern hemisphere summer and winter seasons, respectively. Solid phase extraction (SPE) was used to extract the analytes from the water samples and liquid chromatographytandem mass spectrometry (LC-MS/MS) used for analysis. The mean PFAS concentrations detected ranged from 1.38-346.32 ng•L-1 and 2.31-262.29 ng•L-1 in the Hartbeespoort Dam and Roodeplaat Dam, respectively. Perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS) and perfluoroheptanoic acid (PFHpA) were the most dominant PFASs detected. The PFAS concentrations detected were higher in summer than in winter, but the difference between seasons was not statistically significant (p = 1). Furthermore, the concentrations of short-chain PFASs were higher than the longer chains. Overall, the PFAS concentrations in the present study are comparable to those reported in other parts of South Africa, and also Ghana, higher than the concentrations reported in Uganda, Singapore, and Vietnam, and lower than those in Germany, Japan and China. The measured concentrations of PFOA and PFOS raise concerns of human exposure to these chemicals since they are above the USEPA advisory limit. This suggests that communities living within the vicinity of the dams are most likely to be exposed to these chemicals. [ABSTRACT FROM AUTHOR]

Mercury has been used for many centuries in the production of consumer products such as thermometers, electrical switches, fluorescent light bulbs, batteries, biocides and pesticides, cosmetics and dental amalgam filling, among others. After use, these mercury-containing consumer products form part of the municipal solid waste (MSW). As a result of an unseparated solid waste collection system, mercury-containing wastes tend to end up in landfills where mercury and other pollutants can leach out of products into landfill leachates. The present study, therefore, was conducted with the aim of determining the total mercury (THg) concentrations in leachate and sediment samples collected from 4 selected landfill sites (3 sites in Gauteng Province -- Soshanguve, Hatherly, Onderstepoort and 1 site in Limpopo Province -- Thohoyandou). Groundwater samples were collected from the monitoring boreholes at the four selected landfill sites in the summer and winter periods. An acid digestion method was employed for sample preparation and this was followed by analysis using cold vapour atomic absorption spectrophotometry (CVAAS). The concentration range of total mercury in the Thohoyandou leachate, sediment and groundwater samples was 0.12-2.07 µg/L, 0.03-0.48 µg/g and 0.09-2.12 µg/L, respectively. In Soshanguve, the concentration range of total mercury in leachate, sediment and groundwater samples was 0.10-1.20 µg/L, 0.04-0.62 µg/g and nd -1.66 µg/L respectively, Hatherly concentration range was 0.42-1.31 µg/L and 0.06-0.78 µg/g in leachate and sediment, respectively and in Onderstepoort the concentration range was 0.12-2.41 µg/L, 0.03-0.50 µg/g and 0.05-2.44 µg/L, in leachate, sediment and groundwater, respectively. The findings from this study suggest that there is a likelihood of groundwater pollution by mercury from landfill leachate seepage, particularly for landfills that are not lined with a geomembrane. [ABSTRACT FROM AUTHOR]

Ogugua N Okonkwo,1,2 Toyin Akanbi,2 Chineze T Agweye3 1Eye Foundation Retina Institute, Lagos, Nigeria; 2Department of Ophthalmology, Eye Foundation Hospital, Abuja, Nigeria; 3Department of Ophthalmology, University of Calabar Teaching Hospital, Calabar, NigeriaCorrespondence: Ogugua N Okonkwo, Eye Foundation Retina Institute, Lagos, Nigeria, Tel +234 803 502 7308, Email o_okonkwo@yahoo.comPurpose: To report incidence, clinical presentation, and treatment outcome of full-thickness macular hole (FTMHs) diagnosed post pars plana vitrectomy.Methods: We retrospectively reviewed the demographics, best-corrected visual acuity (BCVA), indication for the primary vitrectomy, time to diagnose the secondary FTMH, optical coherence tomographic (OCT) appearance, and treatment outcome of FTMHs, occurring after vitrectomy performed between January 2019 and December 2020.Results: Six of 523 vitrectomized eyes developed FTMHs, an incidence of 1.1%. There were five females and one male, mean age of 56.5 years (range 37– 85). The indication for primary vitrectomy was rhegmatogenous retinal detachment (RRD) in three eyes, one eye each for sub internal limiting membrane hemorrhage from a ruptured macroaneurysm, vitreous hemorrhage from polypoidal choroidal vasculopathy (PCV), and pre-insertion of Ahmed glaucoma drainage device (GDD). FTMHs occurred within one week to three months after vitrectomy (time from primary vitrectomy to the identification of the secondary MH was a mean of 1.03 months). Mean BCVA in all six MH eyes was log MAR 0.9 (Snellen: 6/54). Anatomical closure was achieved after one surgery in three eyes, two surgeries in 1 eye, after photodynamic therapy (PDT) in the PCV eye, and one patient declined surgery. The mean BCVA in the four surgically closed MH eyes improved marginally from log MAR 0.82 (Snellen: 6/38) to log MAR 0.72 (Snellen: 6/30), mean follow-up 7.6 months.Conclusion: Post-vitrectomy FTMH is rare, and RRD was the commonest indication for initial vitrectomy. We observed that all secondary MHs were closed successfully using the inverted internal limiting membrane (ILM) flap technique with limited improvement in vision. The visual outcome of these secondary MHs trails behind that of idiopathic MHs.Keywords: full thickness macular hole, vitrectomy, complications of vitrectomy, epiretinal membrane, optical coherence tomogram, inverted internal limiting membrane flap

The present study describes a simple sensor developed from Fe3O4 and MWCNT nanoparticles for the simultaneous detection of sulfamethoxazole (SMX) and trimethoprim (TMP). Determination was carried out using cyclic voltammetry, electrochemical impedance spectroscopy, chronoamperometry and differential pulse voltammetry. Oxidation peaks were obtained at 910 mV (SMX) and 1120 mV (TMP) in Britton–Robinson buffer (pH 6.0). LODs of 1.10 × 10−8 M (SMX; 2.79 μg L−1) and 2.10 × 10−8 M (TMP; 6.10 μg L−1) were obtained. The Fe3O4/MWCNT/GCE showed good stability and selectivity. Furthermore, the simultaneous detection of SMX and TMP in tablets, urine and water was possible using the standard addition method. [ABSTRACT FROM AUTHOR]