35 research outputs found
Polypoidal Choroidal Vasculopathy
Polypoidal choroidal vasculopathy (PCV) is a disease of the choroidal vasculature that may result in sub-retinal hemorrhage and serous detachment of the retinal pigmented epithelium (RPE), leading to sub-retinal brosis and, sometimes, permanent vision loss. This report describes a case of PCV in an African-American female over the course of 1 year and demonstrates the progression of PCV, from being relatively asymptomatic to the development of a visually significant sub-retinal hemorrhage. She is currently being treated with Avastin intravitreal injections with some resolution of her symptoms and a reduction of sub-retinal bleeding
Models of Resistance: Novice Teachers Negotiating Barriers to Best Practice
The purpose of this study was to examine how graduates from three teacher education programs made decisions regarding literacy instruction and assessment as well as the extent to which they were able to implement practices learned in their education programs. Participants were interviewed and observed multiple times, and a variety of documents, such as lesson plans, assessments, and journal prompts, were collected. Data were analyzed using the constant comparative method and Bourdieu’s concepts of field, capital, and habitus. Although the participants initially accepted the existing practices of their schools, they later implemented concepts learned in their education programs. The ways in which they resisted the barriers they faced included resistance with conflict, resistance with an attitude, resistance with relationship, and resistance by making a change
Effects of Thresholding on Voxel-Wise Correspondence of Breath-Hold and Resting-State Maps of Cerebrovascular Reactivity
Functional magnetic resonance imaging for presurgical brain mapping enables neurosurgeons to identify viable tissue near a site of operable pathology which might be at risk of surgery-induced damage. However, focal brain pathology (e.g., tumors) may selectively disrupt neurovascular coupling while leaving the underlying neurons functionally intact. Such neurovascular uncoupling can result in false negatives on brain activation maps thereby compromising their use for surgical planning. One way to detect potential neurovascular uncoupling is to map cerebrovascular reactivity using either an active breath-hold challenge or a passive resting-state scan. The equivalence of these two methods has yet to be fully established, especially at a voxel level of resolution. To quantitatively compare breath-hold and resting-state maps of cerebrovascular reactivity, we first identified threshold settings that optimized coverage of gray matter while minimizing false responses in white matter. When so optimized, the resting-state metric had moderately better gray matter coverage and specificity. We then assessed the spatial correspondence between the two metrics within cortical gray matter, again, across a wide range of thresholds. Optimal spatial correspondence was strongly dependent on threshold settings which if improperly set tended to produce statistically biased maps. When optimized, the two CVR maps did have moderately good correspondence with each other (mean accuracy of 73.6%). Our results show that while the breath-hold and resting-state maps may appear qualitatively similar they are not quantitatively identical at a voxel level of resolution
The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance
INTRODUCTION
Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic.
RATIONALE
We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs).
RESULTS
Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants.
CONCLUSION
Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century
Case Report: Purtscher Retinopathy Following Subarachnoid Hemorrhage and Femur Fracture
Purtscher retinopathy is a rare microvasculopathy which occurs following trauma. Clinical presentation consists of cotton wool spots, retinal hemorrhages, and Purtscher flecken within the posterior pole. A similar display of findings has been associated with a heterogenous group of systemic disorders, but the classification of Purtscher-like retinopathy is reserved for these non-traumatic etiologies. Although the pathogenesis remains to be fully understood, clinical and experimental evidence implicate an occlusive vasculopathy of the precapillary arterioles. Clinical presentation resolves in the months following trauma; however, visual prognosis is variable. There are presently no evidence-based treatments available for Purtscher retinopathy.  
Rapport de cas : Rétinopathie de Purtscher à la suite d’une hémorragie sous-arachnoïdienne et d’une fracture du fémur
La rétinopathie de Purtscher est une microvasculopathie rare qui survient à la suite d’un traumatisme. La présentation clinique se caractérise par la présence de nodules cotonneux, d’hémorragies rétiniennes et de taches de Purtscher dans le pôle postérieur. Bien que des résultats semblables aient été associés à un groupe hétérogène de troubles systémiques, ces étiologies non traumatiques sont considérées comme une pseudo-rétinopathie de Purtscher. La pathogenèse n’est pas encore pleinement comprise; néanmoins, les données cliniques et expérimentales mettent en cause une vasculopathie occlusive des artérioles précapillaires. La présentation clinique se résorbe habituellement dans les mois qui suivent le traumatisme. Toutefois, le pronostic visuel varie. Il n’existe actuellement aucun traitement fondé sur des données probantes pour la rétinopathie de Purtscher
Connecting
Louise Morgan—Street Science: An English Teacher’s Introduction to Street Life.
Amy Wink—\u27In the Middle of Difficulty Lies Opportunity\u27— Albert Einstein
Marcia Nell—The New Partnership
Gergana Vitanova—Negotiating an Identity in Graduate School as a Second Language Speaker.
Judy Huddleston—A Cat in the Sun: Reflections on Teaching
Concussion Guidelines Step 1: Systematic Review of Prevalent Indicators
BACKGROUND: Currently, there is no evidence-based definition for concussion that is being uniformly applied in clinical and research settings.
OBJECTIVE: To conduct a systematic review of the highest-quality literature about concussion and to assemble evidence about the prevalence and associations of key indicators of concussion. The goal was to establish an evidence-based foundation from which to derive, in future work, a definition, diagnostic criteria, and prognostic indicators for concussion.
METHODS: Key questions were developed, and an electronic literature search from 1980 to 2012 was conducted to acquire evidence about the prevalence of and associations among signs, symptoms, and neurologic and cognitive deficits in samples of individuals exposed to potential concussive events. Included studies were assessed for potential for bias and confound and rated as high, medium, or low potential for bias and confound. Those rated as high were excluded from the analysis. Studies were further triaged on the basis of whether the definition of a case of concussion was exclusive or inclusive; only those with wide, inclusive case definitions were used in the analysis. Finally, only studies reporting data collected at fixed time points were used. For a study to be included in the conclusions, it was required that the presence of any particular sign, symptom, or deficit be reported in at least 2 independent samples.
RESULTS: From 5437 abstracts, 1362 full-text publications were reviewed, of which 231 studies were included in the final library. Twenty-six met all criteria required to be used in the analysis, and of those, 11 independent samples from 8 publications directly contributed data to conclusions. Prevalent and consistent indicators of concussion are (1) observed and documented disorientation or confusion immediately after the event, (2) impaired balance within 1 day after injury, (3) slower reaction time within 2 days after injury, and/or (4) impaired verbal learning and memory within 2 days after injury.
CONCLUSION: The results of this systematic review identify the consistent and prevalent indicators of concussion and their associations, derived from the strongest evidence in the published literature. The product is an evidence-based foundation from which to develop diagnostic criteria and prognostic indicators