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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
241

Disease Tolerance, Epigenetic Inheritance, and Surviving Pathogenic Viral Infections

Silverstein, Noah J. 18 August 2021 (has links)
Health is often defined in terms of absence of disease or pathological processes, but this is a definition of exclusion and incomplete. For example, SARS-CoV-2 viral load does not reliably predict disease severity, and so individuals must vary in their ability to control inflammation and maintain normal tissue homeostasis. This host defense strategy is called disease tolerance, and better understanding of disease tolerance mechanisms could change the way that we treat disease and work to maintain health. The first project presented in this dissertation found that after accounting for effects of age and sex, innate lymphoid cells (ILCs), but not T cells, were lower in adults and children sick with COVID-19 or MIS-C, independent of lymphopenia. Furthermore, abundance of ILCs, but not of T cells, correlated inversely with disease severity. These blood ILCs were shown to produce amphiregulin, a protein implicated in disease tolerance and tissue homeostasis, and the percentage of amphiregulin-producing ILCs was lower in males. These results suggest that, by promoting disease tolerance, homeostatic ILCs decrease morbidity and mortality associated with SARS-CoV-2 infection, and that lower ILC abundance accounts for increased COVID-19 severity with age and in males. The second project describes a novel mouse model of epigenetic inheritance wherein paternal influenza A virus (IAV) infection results in less severe influenza disease in IAV infected offspring. This offspring phenotype was not attributable to differences in viral load, indicating a possible difference in disease tolerance. Paternal caloric deprivation decreased, and influenza B virus infection increased, offspring influenza disease severity, and in vitro fertilization demonstrated sperm are sufficient to transfer IAV-associated epigenetic inheritance phenotypes. These findings represent a foundation for further work that, by continuing to elucidate the mechanisms of disease tolerance and epigenetic inheritance, could provide novel therapeutic interventions to help promote and maintain health.
242

Reactive Blade Coating for Low-Cost Fabrication of Self-Assembled Metal Nanoparticles for Bio-Applications: Disinfecting SARS-CoV-2 to Limit the Spread of COVID-19 Illness

Ebrahimzadeh Asl Tabrizi, Bita 30 April 2021 (has links)
Considerable attention has been focused on nanomaterials and their extensive applications. Metallic nanoparticles, especially gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs), due to their superior physical, chemical, and optical properties, are vastly developed for numerous biomedical applications such as drug and gene delivery systems, diagnostic biosensors, imaging, and therapeutics. This study presents a low-cost method for the fabrication of self-assembled metallic nanoparticles, including gold and silver, via a reactive blade coating process, which is carried out based on in situ reduction of the metal precursors. This technique is a roll-to-roll compatible technique suitable for scalable nanomanufacturing. Oleylamine was used as a reducer agent, and gold (III) chloride hydrate and silver salts, including silver nitrate and silver perchlorate hydrate, were used as the metal precursors. Fabrication was carried out by first blade coating the reducer ink and subsequently coating the precursor ink followed by 3 hours of heat treatment. Various solvent systems were used to examine the effect of different solvents on the fabrication process. Surface morphology, crystalline phase composition, and plasmon resonance of the coated samples were characterized by scanning electron microscopy (SEM), X-ray diffractometer (XRD), and UV-Vis spectroscopy, respectively. Results demonstrated the synthesis of spherical self-assembled AuNPs using toluene (TOL) and isopropyl alcohol (IPA) for reducing and precursor solvents, respectively. Changing the concentration of reactants or increasing the coating layers exhibited a change in the average size of AuNPs. Self-assembled AuNPs thin films were also demonstrated to have the potential to be used as a biosensing platform based on localized surface plasmon resonance (LSPR) effect to detect the elevated levels of glucose in an aqueous solution. Recently, the world has faced a pandemic of Covid-19 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which has threatened human health and has brought a worldwide devastating economic and social crisis. Hence, finding a solution to mitigate the current breakout of Covid-19 is vital to protect the international community from its causing harm. AgNPs as an antimicrobial agent, which has exhibited promising antiviral activity against several viruses, can offer a resolution to combat the spread of Covid-19. In this regard, AgNPs thin films were fabricated analogously via blade coating using various reducer and silver salt inks made of different solvent systems. Virucidal efficacy of reactive blade coated AgNPs on glass substrates was analyzed against human coronavirus 229E, a virus from the Coronavirus family, as a surrogate SARS-CoV-2 (according to the Level 2 Biosafety facility at uOttawa). Plaque forming assay indicated more than 99.99% reduction in infectivity of the virus when it contacts the AgNPs coated glass for 30 min before infecting cells. These results suggest the excellent potential for reactive blade coated AgNPs as an antiviral agent against coronavirus to avoid the spread of the virus.
243

Characterization of virus-host interactions using cellular thermal shift assays (CETSA)

Lissner, Robin January 2021 (has links)
No description available.
244

Mesenchymal Stem/Stromal Cells as a Therapeutic Intervention for COVID-19: A Living Systematic Review and Meta-Analysis

Kirkham, Aidan 24 June 2022 (has links)
Background: Since its emergence in December 2019, SARS-CoV-2, the coronavirus responsible for COVID-19, has spread across the globe, infected millions of people and caused several million deaths. One promising intervention to combat the ongoing COVID-19 pandemic is mesenchymal stem/stromal cells (MSCs). Many trials were registered at the onset of the pandemic to determine the safety and efficacy of MSCs in COVID-19 patients. However, currently published studies are underpowered to provide an estimate of safety and efficacy on their own. Thus, a living systematic review (SR) is needed to establish the benefits and drawbacks of MSCs for COVID-19 on a relevant timescale. Methods: Systematic literature searches were conducted on Feb 3rd, 2021 and November 15th, 2021 to identify all English-language, full-text, clinical studies examining MSCs to treat COVID-19. (PROSPERO:CRD42021225431). Findings/Conclusions: Our first search identified nine studies (4 controlled) examining the use of MSC derived products to treat COVID-19 patients. This first iteration of our SR revealed that MSCs were safe and reduced mortality in patients suffering from COVID-19. However, risk of bias (RoB) and poor adherence to ISCT cell product characterization guidelines limited the strength of our conclusions. In the second iteration of our living SR, we only included controlled studies to strengthen our conclusions. We identified eleven controlled studies (5 RCTs). MSCs continued to demonstrate safety and efficacy at reducing mortality at study endpoint (RR: 0.50 [0.34 to 0.75, 95% CI, p=0.0006, I2=0%]). However, we continued to encounter barriers which prevented us from drawing more definitive conclusions. A master protocol appears necessary to facilitate the accelerated accumulation of high-quality evidence where standardized outcome reporting and consistent product characterization allow for a more definitive and timely estimate regarding the safety and efficacy of this cell-based therapy for COVID-19.
245

A RAPID PAPER-BASED COLORIMETRIC MOLECULAR TEST FOR SARS-COV-2 POINT-OF-CARE DIAGNOSTIC

Jiangshan Wang (10725807) 29 April 2021 (has links)
<p>In the year of 2020, an international pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has afflicted tens of millions of people’s life also disrupting global economics. Diagnostic testing is an important part of ensuring public health until a vaccine that has been shown to be safe and effective is made available to the general public. Most tests for detecting COVID-19 utilize quantitative polymerase chain reaction (qPCR) assays, which is a specific and relatively simple quantitative assay that could provide adequate sensitivity for diagnosing early infection. Although powerful, these lab-based molecular assays have a significant lag time, usually several days before receiving results. To satisfy the needs of different purposes (diagnostics, screening, and surveillance), a unified approach is impractical. This thesis presents an alternative testing method supporting the current procedure of point of care (POC) testing and in community testing. This paper-based test overcomes the limitations of current testing methods by utilizing reverse-transcription loop-mediated isothermal amplification (RT-LAMP) and receiving the result on-site by a color change in the presence of the virus within 60 minutes. The test utilizes untreated freshly collected saliva, a less invasive specimen, as the sample and possesses a limit of detection (LoD) of 200 copies of virus per microliter of whole saliva with an analytical sensitivity of 97% and analytical specificity of 100%. The test requires minimal operator training and could be fabricated on a large-scale using roll-to-roll methods. Since the test is based on nucleic acids, the testing platform itself lends to further applications <a>including food safety monitoring, animal diagnostic, etc. simply by changing the specific primers</a>. </p>
246

Clinical characteristics of acute kidney injury in the first 13 critically ill patients infected with SARS-CoV-2 (COVID-19) at a peruvian hospital; a preliminary report

Benites-Flores, Irwing R., Valdivia-Vega, Renzo P., Alcalde-Ruiz, Susan F., Espinoza-Rojas, Hugo J. 01 April 2021 (has links)
Introduction: The high transmissibility and lethality of the novel coronavirus SARS-CoV-2 (COVID-19) have been catastrophic. Acute kidney injury (AKI) is one of the frequent complications in patients with respiratory insufficiency caused by the virus. The pathogenic mechanism is based on the binding of its S-proteins to the angiotensin-converting enzyme (ACE) receptors, which will trigger a cellular damage. A podocyte and tubular compromise are found in the kidneys which can lead to tubular necrosis and the consequent AKI. Objectives: The objective of this report is to identify the main risk factor to develop AKI in patients infected with SARS-CoV-2 with critical acute respiratory distress. Patients and Methods: We performed this report study, collecting data from 48 ICU patients. Data from 13 of them who developed AKI and needed renal replacement therapy (RRT)were analyzed. Clinical characteristics and laboratory findings were reported using STATA 10.0. Results: AKI was present in 27.08% of patients, mostly male (92.3%) with a mean age of 63.8 years old. Hypertension, diabetes and obesity were the main comorbidities in those patients. Additionally, the meantime between admission and AKI diagnosis was 2.69 days. All patients showed fibrinogen, D-dimer, ALT and values above normal range. Mortality was seen in 61.5% of patients. Conclusion: This report tries to show AKI as an important clinical manifestation in critically ill patients infected with SARS-CoV-2, with high mortality. Further studies are needed to demonstrate if there are independent risk factors. / Revisión por pares
247

Impact of Covid-19 Response Strategies on the Rate of Change in Mortality in Europe During the First and Second Waves: A Retrospective Cohort Study

Quattrini, Nicole January 2021 (has links)
The coronavirus disease 2019 (COVID-19) has led to more than 3,000,000 deaths globally. During the first year of the pandemic, countries have focused their response strategies on non-pharmaceutical interventions (NPIs) such as lockdowns and use of facial coverings. Because of collateral effects (psycho-social, and economical) by NPIs, investigating their effectiveness is increasingly important for optimal policies. The aim of this study is to investigate whether varying degrees of response strategies affect the rate of change in mortality at specific time points in the epidemic. The containment and health index (CHI) is used to identify the degree of response measures adopted by each country. Six time points around the peak of daily mortality are identified for the first two epidemiological waves for 40 European countries. The response was then correlated to the rate of change of mortality observed over one week 26 days later (time lag for the intervention to take effect). Spearman’s rank correlation coefficient was used for the unadjusted analysis, and multiple linear regression is used in the adjusted analysis. The intensity of CHI reduced the rate of increase of mortality before the first epidemic peak but had no detectable effect at any other time point. Different covariates and interactions between CHI and covariates such as population density and GDP, affected the rate of change of mortality at different time points during the two waves. NPIs may be effective, as suggested by a significant effect of CHI on mortality early in the first wave. However, the effect is not consistent across time points, and the extent of collateral damage suggests a closer look at other factors influencing the epidemic is necessary.
248

Vaccin mot SARS-CoV-2 – en utvärdering av effektivitet och säkerhet av ledande vaccin : En Litteraturstudie / Vaccine against SARS-CoV-2 – an evaluation of effectivity and safety of the leading vaccines : A Literature Study

Wrywood, Sean January 2021 (has links)
Introduktion: Coronavirus är RNA-virus med ett lipidhölje som är täckt utav karaktäristiska spikprotein. De mest kända coronavirusvarianterna är SARS-CoV-1 som var aktiv mellan 2002-2004, MERS-CoV som har varit aktiv sedan 2012 och SARS-CoV-2 som har varit aktiv sedan 2019–tillsvidare. SARS-CoV-2 infektionen betecknades januari 30 2020 som en pandemi. Flera läkemedelsföretag har forcerat ??? till att framställa vaccin riktad mot SARS-CoV-2, “The United States Food and Drug Administration” (FDA) och “European Medicines Agency” (EMA) har nödgats att ge ut “Emergency Use Authorization (EUA) i hopp om att få kontroll på dess spridining. Syfte och mål: Syftet med arbetet är att undersöka säkerheten och effektiviteten hos de EMA-godkända vaccinerna riktade mot SARS-CoV-2. Metod: Studierna för vardera vaccin hittades och valdes ut genom World Health Organizations (WHO) “Draft landscape and tracker of COVID-19 candidate vaccines”. Totalt inkluderades åtta studier baserade på tio kliniska prövningar som undersökte säkerheten och effektiviteten hos de fyra ledande vaccinerna från Pfizer BioNTech, Moderna, AstraZeneca och Johnson &amp; Johnson. Resultat: De fyra undersökta vaccinerna visade en god säkerhet utan grövre biverkningar. De vanligaste biverkningarna hos samtliga vaccin var lokal smärta, trötthet och huvudverk. Dessa biverkningar varade mellan en till två dagar efter vaccination och var till större del milda. Större skillnader kunde ses hos de olika vaccinernas effektivitet, Pfizer BioNTech och Modernas mRNA-vacciner visade på effektiviteter runt 95% medan AstraZeneca och Johnson &amp; Johnsons adenovirus-vektor-vacciner visade på effektiviteter runt 66-70%. Diskussion: Inga större skillnader i säkerhet kunde ses mellan de undersökta vaccinerna. AstraZeneca använde ett influensa vaccin istället för isoton vattenlösning till deras kontrollgrupper. Detta kan ha haft en påverkan på placebo och resultaten från deras prövningar. En tydlig skillnad i effektivitet kunde ses mellan de olika vaccintyperna, vilket har ett stort inflytande på hur lätt man kan inducera flockimmunitet hos en befolkning. Eftersom flockimmunitet har en stor roll i både att bromsa spridningen men även i att förebygga förekomsten av nya virus varianter så bör endast mRNA vacciner rekomenderas om möjligt. / Introduction: Coronaviruses are RNA viruses with a lipid envelope that is covered by characteristic spike protein. The most well-known coronaviruses are SARS-CoV-1 which were active between 2002-2004, MERS-CoV which is active since 2012 and SARS-CoV-2 which is active since 2019. SARS-CoV-2 was designated a pandemic January 30, 2020. Several pharmaceutical companies have been rushing to produce vaccines targeting SARS-CoV-2, The United States Food and Drug Administration (FDA) and the European Medicines Agency (EMA) have had to issue Emergency Use Authorization (EUA) in the hope of gaining control of its spread. Objective: The purpose of this study is to investigate the safety and efficacy of the EMA-approved vaccines targeting SARS-CoV-2. Method: The studies for each vaccine were found and selected through the World Health Organizations' (WHO) "Draft landscape and tracker of COVID-19 candidate vaccines". A total of eight studies were included based on ten clinical trials examining the safety and efficacy of the four leading vaccines from Pfizer BioNTech, Moderna, AstraZeneca and Johnson &amp; Johnson. Results: The four vaccines examined showed good safety without any serious side effects, the most common side effects with all vaccines were local pain, fatigue, and headache. These side effects lasted between one to two days after vaccination and were mostly mild. Larger differences could be seen in the efficacy of the different vaccines, with Pfizer BioNTech and Moderna's mRNA vaccines showing efficacies of around 95%. While AstraZeneca and Johnson &amp; Johnson's adenovirus vector vaccines showed efficacies of around 66-70%. Discussion: No major differences in safety could be seen between the vaccines examined. AstraZeneca used an influenza vaccine instead of isotonic aqueous solution for their control groups, this may have had an impact on placebo and thus the results of their trials. A clear difference in efficacy could be seen between the different types of vaccines. This has a great influence on how easily one could induce herd immunity to a population. Herd immunity plays a major role in both slowing the spread but also in preventing the occurrence of new virus variants, therefore mRNA vaccines should be recommended if possible.
249

Seguridad de las vacunas contra la COVID-19

Chaparro Mérida, Nataniel Aldo, Samper, Dayany Moreno, Franco Lacato, Alex Omar 22 December 2021 (has links)
El desarrollo y producción de vacunas seguras y eficaces contra la enfermedad por coronavirus 2019 (COVID- 19) ofrece la esperanza para el control de la pandemia actual. Los eventos adversos posteriores a la inmunización son respuestas indeseadas o acontecimientos involuntarios que siguen a la vacunación, y que deben ser cuidadosamente vigilados, ya que todas las vacunas, incluyendo las desarrolladas contra el SARSCoV- 2, requieren cumplir con los criterios de seguridad para su administración en humanos. Se recopiló la información de la base de datos de PubMed/Medline durante los meses de agosto de 2020 a noviembre de 2021. La mayoría de los eventos adversos identificados en los ensayos clínicos fueron leves o moderados; sin embargo, se identificaron eventos trombóticos asociados a algunas vacunas basadas en vectores virales contra la COVID-19 en estudios de seguimiento, aunque se requiere la conclusión de los distintos estudios en curso y vigilancia poscomercialización para determinar todos los posibles eventos adversos y de especial interés.
250

SARS-CoV-2 y su efecto a nivel de tejido renal: Una revisión narrativa / Effect of SARS-CoV-2 on kidney tissue: A narrative review

Flores Gavino, Aldo Paul, Espinoza Anchaygua, Ricardo Daniel 19 March 2021 (has links)
Se describe la evidencia actual del efecto del SARS-CoV-2 a nivel de tejido renal. Se realizó una revisión narrativa de los artículos publicados en SCOPUS y PUBMED hasta septiembre de 2020. Los resultados se dividieron en las siguientes secciones: evidencia del efecto directo del virus en el riñón, mecanismos de invasión celular, mecanismos de injuria celular y las potenciales implicaciones terapéuticas de estos hallazgos. El SARS-CoV-2 invade las células del túbulo proximal y los podocitos, a través del receptor ECA-2. La invasión y replicación viral podrían producir daño mediante un efecto citopático directo aunado a un daño mediado por la respuesta inmune. Debido a la expresión celular de ECA-2, se ha propuesto a los Inhibidores del Sistema Renina–Angiotensina–Aldosterona como un potencial tratamiento contra la COVID-19. Sin embargo, a la fecha, la evidencia no apoya su uso. / We describe evidence on SARS-CoV-2 effect on the kidney. We carried a narrative review of articles published in SCOPUS and PUBMED until September 2020. The results were divided into six topics: evidence of direct effect of virus on the kidney, mechanisms of cellular invasion, mechanisms of kidney injury, and potential therapeutic implications. SARS-Cov-2 gains access to proximal tubule cells and podocytes via ACE-2 receptors. Viral invasion and replication may induce kidney damage through a direct cytopathic effect and immune-mediated damage. Due to ACE-2 cellular expression, Renin–Angiotensin–Aldosterone System Inhibitors have been proposed as potential treatment for COVID-19. However, current evidence does not support its therapeutic use. / Trabajo de investigación

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