• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 107
  • 81
  • 26
  • 9
  • 4
  • 2
  • 2
  • 2
  • Tagged with
  • 263
  • 263
  • 263
  • 180
  • 178
  • 90
  • 57
  • 52
  • 49
  • 42
  • 40
  • 27
  • 23
  • 22
  • 22
  • 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.
1

Hallazgos ecocardiográficos en trabajadores de salud recuperados de infección leve por Sars- CoV-2 de un hospital IV covid del Perú / Echocardiographic findings in health workers recovered from mild infection by sars-cov2 from a covid IV hospital in Peru

Baltodano-Arellano, Roberto, Cupe-Chacalcaje, Kelly, Rojas, Paol, Meneses, Giovanni, Urdanivia-Ruiz, Dante, Rafael-Horna, Eliana, Falcón-Quispe, Luis, Cachicatari-Beltran, Angela, Hurtado-Belizario, Karla Sue América, Levano-Pachas, Gerald 04 February 2022 (has links)
Objetivos: Determinar hallazgos estructurales o funcionales ecocardiográficos en pacientes recuperados de infección SARS-CoV-2. Materiales y métodos: Estudio observacional transversal, que incluyó pacientes trabajadores de un hospital nacional COVID, estudiados entre 3 a 6 meses luego del diagnostico de infección SARS-CoV-2. La exploración ecocardiográfica se desarrolló de forma sistemática e incluyó las modalidades convencionales. Resultados: Se incluyeron 65 casos con infección-CoV-2, la edad promedio fue 37.7 años, la obesidad resultó la comorbilidad mas frecuente (13.8%) y la presentación clínica leve fue la de mayor prevalencia (84.6%). Las medias del diámetro diastólico y la fracción de eyección ventrículo izquierdo fueron 42mm y 57% respectivamente. Así mismo la media del diámetro basal del ventrículo derecho fue de 31mm, de la fracción de acortamiento 44% y en todos los casos se reportó probabilidad de hipertensión pulmonar como baja. No se encontró efusión pericárdica en ninguno de los casos. Conclusiones Los pacientes recuperados de infección SARS-CoV-2, no presentan alteraciones estructurales ni funcionales en la exploración ecocardiográfica convencional.
2

Host Biomarkers of Respiratory Infection / CHARACTERIZATION OF CXCL10 AS A BIOMARKER OF RESPIRATORY TRACT INFECTIONS DETECTABLE BY OPEN-SOURCE LATERAL FLOW IMMUNOASSAY

Mikkelsen, Dayna January 2022 (has links)
Background: Respiratory tract infections are responsible for millions of deaths annually. Interferon-stimulated genes (ISGs) play a significant role in fighting off viral respiratory tract infections in the antiviral defence system. Measuring extracellular protein products of ISGs could be potential biomarkers of viral infection. Although, the feasibility and performance of ISGs as functional and robust clinical biomarkers from a non-invasive sample format remains unknown. Methods: Three ISGs, CXCL10, CXCL11, and TNFSF10, were examined in in-vivo and in-vitro gene expression datasets (RNA-sequencing and microarray) infected with common respiratory tract infections (Rhinovirus, Respiratory syncytial virus, influenza A and SARS-CoV-2) samples and compared to negative controls. Using qualitative selection criteria of 1) elevated presence in at least one dataset with viral infection, 2) secreted protein product, and 3) commercially available antibodies for detection, CXCL10, CXCL11 and TNFSF10 gene expression levels were assessed. A correlation analysis was performed with SARS-CoV-2 infection severity and gene expression kinetics. CXCL10 was subsequently validated at the protein level in saliva as a prerequisite for developing a host-response LFA. Results: CXCL10 and CXCL11 upregulation were positively correlated with RSV compared to control (p < 0.05). CXCL10/CXCL11/TNFSF10 were not different between samples collected from RV infected subjects relative to controls (p > 0.05). No significant association was found with influenza A for all three genes. CXCL10/CXCL11/TNFSF10 upregulation was positively correlated with SARS-CoV-2 infection compared to control (p < 0.001). CXCL10 expression correlated with COVID-19 viral load. CXCL10 was chosen as a lead biomarker candidate based on these analyses that included different virus infections, time-courses, and measures of severity. CXCL10 was not detected at the protein level in healthy saliva but was elevated in saliva from COVID-19 patients. A CXCL10 LFA was developed with a sensitivity of 2 ng/ml in a buffer and artificial saliva. Conclusion: We establish and validate the potential of developing rapid test techniques to examine host immune response from a bioinformatic approach to developing a prototype rapid test with capabilities to be used in point-of-care settings. / Thesis / Master of Science (MSc) / Respiratory tract infections are a leading cause of death and one of the main reasons to seek primary care. Both historically and in the present day, respiratory tract infections remain a massive socioeconomic burden. Current diagnostics fail to quickly identify a respiratory tract infection's etiology, and prognosis, leading to suboptimal patient care and the over prescription of antibiotics. Advanced tools used in academia and research, including next-generation -omics sequencing and metagenomics, have capabilities to identify all nucleic acid material in a sample - including host RNA- which offers potential to improve the diagnosing of respiratory tract infections. However, these technologies have not been integrated into routine care due to economic, technical, and logistical barriers. We explored host RNA (transcriptomics), looking at antiviral interferon-stimulated genes for their potential as a biomarker of viral infection amenable to point-of-care testing platforms from non-invasive sample types.
3

Selection and Binding Validation of Aptamers against Nucleocapsid Protein of SARS-COV-2 Using Capillary Electrophoresis

Gu, Yuxuan 28 September 2023 (has links)
The Coronavirus disease 2019 (COVID-19) pandemic has highlighted the critical need for accurate and sensitive diagnostic tools for detecting the SARS-CoV-2 virus. The nucleocapsid (N) protein is essential for virus replication and plays vital roles in virus assembly, packaging, and RNA transcription. This protein is a crucial component of the viral particle and is less prone to mutations than the other essential proteins in SARS-COV-2. All of these make the N protein a reliable target for virus detection. Aptamers, single-stranded oligonucleotides that can specifically bind to target molecules, have been proposed as a promising alternative to antibodies for detecting and treating viral infections. This study aimed to select DNA aptamers against the N protein of SARS-CoV-2 using capillary electrophoresis (CE) and validate the binding specificity of the aptamers. After selecting seven clones, a preliminary binding validation was performed, and the two best binding clones were identified as ECK4 and ECK6. The structures of the aptamers were then modified by removing the primer regions from the original sequence, and the binding capacity of the truncated aptamers was confirmed. Dissociation constant (KD) values were calculated to provide further supportive information for the quality of the two clones. Additionally, Biolayer interferometry (BLI) was used to calculate Apparent KD as an alternative technique and provided consistent results with CE. Our results demonstrate the successful selection of aptamers for the N protein of SARS-CoV-2 using CE-SELEX. Confirming the aptamers' binding capacity to N protein paves the way for developing aptamer-based diagnostics for COVID-19.
4

Avances en el desarrollo y el uso de las vacunas contra el SARS-CoV-2 / Advances in the development and use of SARS-CoV-2 vaccines

Lanata de las Casas, Claudio F., Ecker Ledesma, Lucie, Gil Merino, Ana I. 07 May 2021 (has links)
Editorial
5

Universidades versis COVID-19

Dirección de Innovación y Transformación 08 1900 (has links)
Como parte importante de la sociedad, las universidades forman un grupo activo que trabaja en la investigaciòn y el desarrollo de iniciativas que combaten el COVID-19
6

Characteristics of COVID-19 in cancer patients: A cross-sectional study in Peru

Payet, Eduardo, Perez, Joan, Sarria, Gustavo, Neciosup, Silvia, Berrospi, Francisco, Vilchez, Sheila, Dunstan, Jorge, Perez, Ronald, Vassallo, Mauricio, Salgado, Santiago, Caparachín, Nanto, Pinto, Joseph A., Holguin, Alexis 01 June 2021 (has links)
Background: Cancer patients are at higher risk of infection and severity of Coronavirus Disease-19 (COVID-19). Management of patients infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is challenging due to the scarce scientific information and treatment guidelines. In this work, we present our Institutional experience with our first 100 patients with oncological malignancies and COVID-19. Patients and methods: We conducted a cross-sectional study of the first 100 patients hospitalised at the Instituto Nacional de Enfermedades Neoplasicas (Lima, Peru) who were positive for SARS-CoV-2 by reverse transcriptase (RT)-PCR during the period 30 March to 20 June. Clinicopathological variables of the oncological disease as well as risk factors, management and outcomes to COVID-19 were evaluated. Results: The mean age was 43.5 years old (standard deviations: ±24.8) where 57% were male patients. In total, 44%, 37% and 19% were adult patients bearing solid tumours, adults with haematologic malignancies and paediatric patients, respectively. Hypertension was the most frequent comorbidity (23%) followed by chronic lung disease (10%). COVID-19-associated symptoms included cough (65%), fever (57%) and dyspnoea (56%). Twelve percent of patients were asymptomatic. Nosocomial infections were more frequent in paediatric patients (84.2%) than in adult patients (16.0%). Patients with uncontrolled oncological disease were most frequent (72%). Anaemia was present in 67% of patients, 68% had lymphopenia, 62% had ferritin value > 500 mcg/L, 85% had elevated lactate dehydrogenase (LDH), 83% D-dimer > 500 ng/mL and 80% C-Reactive Protein > 8 mg/L. The most common complication was acute respiratory failure (42%). Overall fatality rate was 39% where the main cause of mortality was acute respiratory distress syndrome (64.1%). Conclusion: Paediatric patients had better outcomes than adult populations, and a high number of asymptomatic carriers and nosocomial infection, early diagnosis are recommended. Considering oncological treatments 30 days before COVID-19 diagnosis, our data did not reveal an increased mortality. / Revisión por pares
7

Insights in Response to Statewide COVID-19 Sampling in Indiana

Shields, David William, Jr. 05 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / During 2020, the Indiana State Department of Health conducted a longitudinal study of novel severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) virus, the cause of COVID-19 disease, to understand the number of past and current infections as well as the prevalence of disease in the State of Indiana by conducting a survey to participants as well as administering testing for exposure to SARS-COV-2. The study consisted of 3 waves of testing, each spread months apart, consisting of a random sample and a non-random sample. The non-random sample was used to ensure the sample population was representative of the state of Indiana and was used as stratum in the logistic regression model, allowing for the adjustment for nonresponse. These finding indicate that persons of non-White race and persons of Hispanic ethnicity had highest risk of exposure to the virus. Understanding the disparity in health in various racial and ethnic populations and addressing how different communities are impacted by the pandemic, as well as working with the community is paramount when attempting to mitigate a pandemic. In addition, understanding the data from the ambient pandemic when instituting measures to mitigate the spread of viruses is also extremely important for managing health emergencies such as the COVID-19 pandemic.
8

Surface and active site modification of proteins with organometallic markers and inhibitors / Modifikation von Proteinen an der Oberfläche und im aktiven Zentrum durch organometallische Marker und Inhibitoren

Graf, Dominic January 2022 (has links) (PDF)
After implementing a reliable mass spectrometry based kinetic study the indole conjugation with different organometallic indoles led to questions about the electronical and sterical influences on reactivity. The substitution pattern of the ferrocene functionalized indoles at the six-membered ring determines the electron density on the C3 atom, which reacts with the formed Schiff base. Since the experimental results showed the exact opposite trend, covalent docking studies were performed elucidating the importance of surface interactions. These studies were in harmony with the experimental results and determined lysine 33 as most preferable conjugation site as well as substitution in 6-position as most favourable pattern. The amine motif in compounds 6, 7 and 8 proofed to be easily fragmented by the ESI method used. The amide linker in 10 remains intact but shows a lower conversion. Those two inherent characteristics are however preferable for well-defined and site-specific bioconjugation. The synthesis and evaluation of piano stool complex derivatives with manganese and rhenium metal centre 15, 16, 18 and 22 gave additional guidance by the interpretation of applicable structural motifs. The electron-withdrawing carbonyl groups lead to the hindrance of fulvene formation and thus to no fragmentation as seen with the ferrocene group. The total conversion is low compared to 8, only 22 shows a good enough conversion to mainly monoconjugate of 45% and a possible radio-labelling application as 99mTc analogue. As consequence manganese complexes with a stable facial tricarbonyl unit and a tridentate chelator with 4-, 5- and 6-substituted aminomethylindole conjugated through an amide bond were synthesized and consecutively evaluated. The resulting organometallic indole derivatives 29, 30 and 31 all showed a total conversion around 40% similar to 16, but at the same time a rate constant in the range of 10-4 s-1 like the organic indole. Besides the similar conversion, the rate constants followed the trend of the 6-substituted derivative as fastest and then 5- and 4- substituted derivative with decreasing reactivity. For underlining the usage as technetium label for the best out of the series 31, a rhenium analogue was prepared. The resulting compound 32 was especially interesting, because the conversion was even higher than the 70% of 8 with a total of 88%. Additionally, the rate constant was a tenfold higher as well. This rendered compound 32 as best possible 99mTc analogue for further application as radio-label. After the success of 32 and realizing the sterical benefits resulting from the flexible tridentate ligand-system, substitution at the five-membered ring was explored. The complexes 33, 34 and 35 are based on indole-2-carboxylic acid and with the difference of the length of the alkyl spacer between amide and complex to probe for the influence and sterical hindrance, but all three derivatives showed no conjugation which excludes functionalization in 2-position. As the C3 is used for the actual bioconjugation, the last possible derivatization was realized on the indole-N1 by using 1-(3-bromopropyl)indole as building block during the synthesis of the ligand-system. The corresponding manganese 36 and rhenium 37 complexes both showed similar properties of a moderate conversion like 22 and a rate constant in the range of 10-5 s-1. In conclusion the rhenium complex 32 with the 6-substitution pattern at the tridentate indole-bearing ligand remains the most promising structure. The here developed liquid chromatography coupled mass spectrometry-based assay for the determination of inhibitory activity of drug candidates against the 3CLpro of the sever acute respiratory syndrome coronavirus type 2 was successfully implemented and especially designed to give, due to the available absorption spectra and corresponding mass traces, further insight in the otherwise through fluorescence resonance energy transfer-based assays neglected influences on the inhibition results. Starting with a literature-known quinolone containing covalent inhibitor 42 an N1-methylated derivative 43 and their analogues 44 and 45 in which the benzoic acid was exchanged for ferrocene carboxylic acid were synthesized. The inhibition of 3CLpro was evaluated by the concentration of initial 15mer peptide left after incubation and for that purpose the for 280 nm defined molar attenuation coefficient of (26.41±0.59) L*mol-1*cm-1 determined and used. The results showed a reaction of DL dithiothreitol with the less stable benzoic acid esters leading to a moderate inhibitory effect. The methylation in N1-position showed an increase in stability. The methylated and with ferrocene carboxylic acid functionalized derivative showed a complete inhibition during the timeframe of the assay. In search of a fluorescent and therefore traceable inhibitor, 4 hydroxycoumarin was used to synthesize the analogue with benzoic acid 49 and ferrocene carboxylic acid 50. Both derivatives were less stable than their analogues but exhibited the same trend of a more stable ferrocene-derived compound, which exerted a higher inhibition as well. After preparing and testing the model thioester 53 and showing an inactivation of the established inhibitor ebselen, it was concluded that the reaction with DL dithiothreitol reduces the concentration of active intact inhibitor and therefore decreases the inhibition rate during the assay. The next step was proofing the reducing agent as non-essential for the fast assay conducted in a timeframe of 5 min to circumvent the negative influence of DL dithiothreitol. By excluding every inhibition-altering part, the resulting method is the perfect tool for precise statements in relation of inhibitory activity. Then the inhibition assay was repeated for ebselen and the best out of the here introduced organometallic inhibitors 45. Both give equivalent results of a complete inhibition during the measurement. The implemented liquid chromatography coupled mass spectrometry-based assay has many advantages over the fluorescence resonance energy transfer-based assays in which all the information and insight accumulated by the evaluation of uv/vis traces and mass spectra are not available leading to wrong or deviating results regarding the inhibitory capacity of inhibitor candidates. / Nach der erfolgreichen Implementierung einer auf Massenspektrometrie basierenden Methode, um kinetische Studien über die Indolkonjugation durchzuführen, kamen Fragen über die elektronischen und sterischen Einflüsse auf die Reaktivität auf. Das Substitutionsmuster der Ferrocen-funktionalisierten Indole am sechsgliedrigen Ring bestimmt die Elektronendichte am C3-Atom, welches wiederum mit der zuvor entstandenen Schiffbase reagiert. Da die experimentellen Daten einen der Elektronendichte entgegengesetzten Trend aufwiesen, wurden Docking-Studien durchgeführt, um die Einflüsse der Wechselwirkungen mit der Proteinoberfläche näher zu beleuchten. Diese entsprachen den experimentellen Werten und zeigten, dass Lysin 33 die bevorzugte Konjugationsstelle ist und dass die Substitution in 6-Position die energetisch günstigste darstellt. Das sekundäre Amin der Verbindungen 6, 7 und 8 wurde unter den ESI-Bedingungen leicht fragmentiert. Die Amid-Bindung von 10 dagegen bleibt intakt und ein langsamerer Umsatz, welcher für einen wohl definierten Umsatz sorgt, wurde beobachtet. Die Synthese und Evaluation der Halbsandwich-Komplexe 15, 16, 18 und 22 gab zusätzlichen Aufschluss über die strukturellen Einflüsse. Die elektronenziehenden Carbonyle behindern die Bildung der Fulvene, welche für die Ferrocen-Derivate beobachtet worden war. Der Gesamtumsatz ist vergleichsweise gering und nur Substanz 22 zeigt eine annehmbare Konversion von 45% an Monokonjugat auf, welches sie wiederum für den Einsatz als 99mTc-Analog qualifiziert. Als direkte Konsequenz wurden Mangankomplexe mit einer stabilen facialen Tricarbonyl-Einheit und einem Indol beinhaltenden tridentaten Liganden synthetisiert. Dies wurde für die 4-, 5- und 6-Substitution durchgeführt um die Komplexe 29, 30 und 31 zu erhalten. Alle drei zeigten eine Konversion von ungefähr 40% und lagen mit einer Ratenkonstante von 10-4 s-1 in dem Bereich des organischen Indols. Die Ratenkonstanten folgten hingegen wiederum dem Trend der begünstigten 6-Position, gefolgt von der 5- und dann 4-Position. Um einen Verglich zu einer analogen Technetium-Verbindung zu ziehen wurde der beste Komplex 31 als Rhenium-Analog 32 hergestellt. Dies wies den bisher höchsten Gesamtumsatz von 88% auf, welches die Konversion von 70% der Verbindung 8 überschritt. Dadurch qualifizierte sich Verbindung 32 als beste Option für eine Umsetzung als Radiomarker. Nach den Erkenntnissen über die begünstigte Sterik der flexiblen tridendaten Liganden wurde versucht den Erfolg auf den Fünfring zu übertragen. Eine auf Indol-2-säure basierende Reihe an Komplexen (33,34,35) mit unterschiedlich langen Alkyl-Ketten zwischen Indol und Metallkomplex sollte Aufschluss über den sterischen Anspruch geben, allerdings war keine Konjugation für alle drei Derivate zu beobachten. Als Konsequenz wurde die 2-Position für weitere Funktionalisierung nicht weiter berücksichtigt. Die letzte verbliebene Stelle war das Indol-amin selbst, welche durch den Einsatz von 1-(3-bromopropyl)indol bei der Ligandensynthese erfolgreich alkyliert wurde. Der resultierende Mangan- 36 und Rhenium-Komplex 37 zeigten eine mit 22 vergleichbare moderate Konversion und um eine Größenordnung kleinere Ratenkonstante. Durch diese Erkenntnisse verblieb der Rhenium-Komplex 32 weiterhin der beste Kandidat für eine Umsetzung als radioaktiver Marker. Der hier beschriebene liquid chromatography coupled mass spectrometry basierte Assay für die Bestimmung der Inhibitions-Wirkung gegenüber der 3CLpro des sever acute respiratory syndrome coronavirus type 2 wurde erfolgreich etabliert. Durch die zusätzlichen Absorptions , sowie Massenspektren wurden weitere Informationen gewonnen, welche in den oft angewendeten Fluoreszenz-Resonanzenergietransfer Assays vernachlässigt werden und zu Verfälschungen der Inhibitionsergebnisse führen. Ausgehend von dem literaturbekannten kovalenten Inhibitor 42 wurde ein N1-methyliertes Derivat 43 hergestellt. Durch den Austausch von Benzoesäure durch Ferrocensäure wurden die Analoge 44 und 45 erhalten. Die Restkonzentration des 15mer Substrats nach der Inkubation wurde als Maß der Inhibition herangezogen. Hierfür wurde der molare Extinktionskoeffizient bei 280 nm mit (26.41±0.59) L*mol-1*cm-1 bestimmt. Die Methylierung führte zu einer erhöhten Stabilität. Der Wirkstoffkandidat 45 zeigte außerdem eine vollständige Inhibition im Rahmen des durchgeführten Assays. 4-Hydroxycoumarin wurde verwendet, um die fluoreszenten Analoga 49 und 50 herzustellen. Beide waren instabiler, wobei das Ferrocen-Derivat wie zuvor eine erhöhte Inhibition aufzeigte. Nach der Synthese und Auswertung des Assays für eine Thioester Modellverbindung 53 und einer nachgewiesenen Inaktivierung des etablierten Inhibitors Ebselen wurden die Nebenreaktionen mit DL-Dithiothreitol als Ursache für einen Konzentrationsabfall der aktiven und intakten Inhibitoren und infolgedessen verringerte Inhibition angenommen. Als nächstes wurde bewiesen, dass der Zusatz eines Reduktionsmittels wie keinen Einfluss auf die Enzymaktivität während des kurzen Assays hat. So wurden alle Einflüsse auf die Inhibitionswirkung ausgeschlossen und der nun makellose Assay für Ebselen und den hier vorgestellten neuartigen organometallischen Inhibitor 45 wiederholt, welche beide eine vollständige Inhibition aufwiesen.
9

La incógnita del coronavirus - Variantes y vacunas - La gestante y su niño / The coronavirus conundrum – Variants and vaccines – The pregnant woman and her child

Pacheco-Romero, José Carlos 03 1900 (has links)
A finales de 2020 se aprobaron las vacunas desarrolladas en el mundo occidental contra el virus SARS-CoV-2, que ya están siendo inoculadas, conjuntamente con vacunas chinas y rusas. Mientras tanto, estamos en una segunda oleada de la enfermedad y el nuevo coronavirus se ha ido transformando para permitirse una mejor propagación, alojamiento y replicación en el ser humano. La enfermedad se manifiesta ahora con nueva sintomatología, mayor contagio, inclemencia y variación en el número de fallecimientos. La infección de la gestante por coronavirus se está presentando con severidad y consecuencias materno perinatales. Ya se inició la vacunación en gestantes y madres lactantes, previa conversación con su ginecólogo sobre los riesgos y beneficios. Este artículo ofrece un breve rel los acontecimientos que tuvieron lugar durante la transición de 2020 a 2021. / In late 2020, vaccines developed in the Western world against the SARS-CoV-2 virus were approved and are currently being inoculated, together with Chinese and Russian vaccines. In the meantime, we are in a second wave of the disease and the new coronavirus has been transforming to allow for better propagation, harboring and replication in humans. The disease now manifests itself with new symptoms, greater contagiousness, severity and variation in the number of deaths. Coronavirus infection of pregnant women is occurring with harshness and maternal and perinatal consequences. Vaccination has been initiated in pregnant women and nursing mothers, after discussion with their gynecologists about risks and benefits. This article provides a b ok place during the transition from 2020 to 2021.
10

Boletín diario de información científica N° 29

Asociación Peruana de Bibliotecas Académicas ALTAMIRA 27 May 2020 (has links)
Boletín que incluye información científica sobre el COVID-19, incluye artículos científicos y artículos preprint actualizados al 27 de Mayo de 2020.

Page generated in 0.1044 seconds