62 research outputs found
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MORSE CODE: A MULTIGROUP NEUTRON AND GAMMA-RAY MONTE CARLO TRANSPORT CODE.
Improved detection of acute HIV-1 infection in sub-Saharan Africa: development of a risk score algorithm
Individuals with acute (preseroconversion) HIV infection (AHI) are important in the spread of HIV. The identification of AHI requires the detection of viral proteins or nucleic acids with techniques that are often unaffordable for routine use. To facilitate the efficient use of these tests, we sought to develop a risk score algorithm for identifying likely AHI cases and targeting the tests towards those individuals
Amplified transmission of HIV-1: comparison of HIV-1 concentrations in semen and blood during acute and chronic infection
This study was conducted to compare viral dynamics in blood and semen between subjects with antibody negative, acute HIV-1 infection and other subjects with later stages of infection
Differential expression analysis of the broiler tracheal proteins responsible for the immune response and muscle contraction induced by high concentration of ammonia using iTRAQ-coupled 2D LC-MS/MS
Análise de PolĂtica Externa e PolĂtica Externa Brasileira: trajetĂłria, desafios e possibilidades de um campo de estudos
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
Impaired functional recovery after stroke in the stroke-prone spontaneously hypertensive rat
<p><b>Background and Purpose:</b> To identify if the stroke-prone spontaneously hypertensive rat (SHRSP) exhibits impaired functional recovery after stroke compared with its normotensive reference strain, the Wistar Kyoto rat (WKY).</p>
<p><b>Methods:</b> In study 1, a 2-mm distal middle cerebral artery occlusion (middle cerebral artery occlusion) was performed in both strains and recovery assessed using a 33-point neurological score. Because SHRSPs displayed much larger infarcts than WKYs, study 2 and study 3 involved extending the length of middle cerebral artery (MCA) occlusion in the WKY to increase the volume and distribution of infarction to comparable levels with SHRSP. Animals were assessed with the neurological score, tapered beam walk, and cylinder tests.</p>
<p><b>Results:</b> In study 1, infarct volume (expressed as a percent of contralateral hemisphere) was WKY 13.1±3% and SHRSP 19.8±1%. Initial neurological deficit was greater (WKY 25±1, SHRSP 22±1, out of a possible 33) and subsequent recovery was poorer in SHRSP. In studies 2 and 3, infarct volume and distribution (study 2, WKY 21.8±1.3%, SHRSP 22.9±3%; study 3, WKY 17.2±2%, SHRSP 16.5±3%) and initial neurological deficit at 2 hours after middle cerebral artery occlusion (study 2 WKY 23±1, SHRSP 22±2; study 3 WKY 25±1 and SHRSP 23±1; mean±SEM) were comparable between strains. However, whereas WKY recovered toward normal scores, SHRSP scored significantly lower 2 weeks (study 2) and 4 weeks (study 3) after middle cerebral artery occlusion. Beam walk data revealed long-term impairment in SHRSP contralateral limb use, compared with WKY, at days 3, 7, and 28 (P<0.05).</p>
<p><b>Conclusions:</b> SHRSP exhibit impaired functional recovery after stroke compared with WKY.</p
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