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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.
61

The immune-modulating activity of Artemisia afra

Kriel, Yusra January 2010 (has links)
Magister Scientiae - MSc / This study shows that herbs can be effectively screened for potiential bio-activity using in vitro methods. Further studies will be needed to better explore Artemisia afra’s effect on immunoregulation, particularly long term effects of the herb on the immune system and its effect on other disease states. / South Africa
62

Clinical decision making of neonatal intensive care professional nurses regarding the employment of bedside blood product filters during neonatal blood transfusion

Morudu, Letennwe Josephine 22 June 2011 (has links)
A lack of information is identified on the ability of professional nurses working in a neonatal intensive care unit to make competent clinical decisions pertaining to the employment of bedside blood product filters during neonatal transfusion. In addition, a lack of complete guidelines existed to aid professional nurses in instances where they are faced with such a decision. A descriptive survey was conducted to determine and describe the knowledge professional nurses working in neonatal intensive care unit have regarding the employment of bedside blood product filters during the transfusion of a neonate with blood or blood products, as well as their ability to make competent clinical decisions in the regard. A questionnaire was designed, which was validated by experts in neonatal intensive care nursing and blood transfusion. The questionnaires were distributed to 10 nominated public and private hospitals with neonatal intensive care units in Gauteng, South Africa, for completion. Participants were self-nominated; they participated in the study of their own free will. Neither the participants’ nor the hospitals’ names were revealed at any stage. Numbers were used to identify the questionnaires. 120 questionnaires were completed and were analysed using descriptive statistics. In the following step, the results obtained from the questionnaires together with literature were used to recommend guidelines for neonatal transfusion utilisation by professional nurses working in neonatal intensive care units. The recommended guidelines were divided into two categories: General guidelines and Specific blood products guidelines. Validity and reliability was enhanced by using staff from ten neonatal intensive care units from the private and public health care sector in Gauteng, South Africa; obtaining a sufficient sample size (n=120); involvement of experts in the field of neonatal nursing science and blood transfusion, as well as a statistician from the University of Pretoria; and verification of results with literature. Ethical principles were adhered to: confidentiality was maintained as no names of any of the hospitals or the participants were disclosed. All information regarding the study was provided to the relevant parties and the participants voluntarily signed an informed consent form. Permission to conduct the study was obtained from the selected hospitals’ management. Approval to conduct the study was obtained from the Ethics Committee of the Faculty of Health Science, University of Pretoria. There were no known risks involved in the study. Recommendations were made for more research on the same topic to be conducted and their outcomes be compared to the results yielded by this study and research to be conducted to related topics. The findings of this study were meant to improve the clinical practice of nursing in neonatal intensive care units. It was therefore recommended that these guidelines be implemented by neonatal intensive care units, training institutions and the South African Blood Transfusion Services. AFRIKAANS : Die navorser het ’n intensiewe oorsig van die bestaande literatuur rakende die kliniese besluitneming van professionele verpleegkundiges in neonatale intensiewe sorgeenhede gedoen. Dit het duidelik uit dié navorsingsoorsig geblyk dat daar baie min gedoen is om die vermoëns vas te stel van professionele verpleegkundiges wat in die neonatale intensiewe sorgeenheid werk met betrekking tot kliniese besluitneming wat die aanwending van bloedprodukfilters tydens neonatale transfusie betref. Aanvullend het die oorsig onthul dat daar geen volledige riglyne bestaan, of voorsien word, vir professionele verpleegkundiges in gevalle waar hul met so ’n besluit gekonfronteer word. Die studie is in twee fases gedoen. In Fase een is ’n vraelys ontwerp gebaseer op konsepte en temas uit die literatuur geїdentifiseer, waarna dit gevalideer is deur kundiges. Die vraelyste is uitgegee aan 10 genomineerde privaat- en publieke hospitale met neonatale inesiewe sorgeenhede in Gauteng vir voltooiing. Die voltooide vraelyste is gesorteer en geanaliseer. Deelnemers is self-genomineerd; die navorser het hulle toegelaat om self te besluit of hulle wou deelneem aan die studie of nie. Deelnemers en hospitale se name is op geen stadium bekend gemaak nie. Nommers is gebruik om die vraelyste te identifiseer. In Fase twee is die uitslae van die vraelyste gebruik om riglyne te ontwerp om gebruik te word in neonatale intensiewe sorgeenhede deur professionele verpleegkundiges vir neonatale transfusie. Riglyne vir neonatale transfusie is geformuleer volgens die uitkoms van die vraelyste in kombinasie sowel as die oorsig van die reeds bestaande literatuur deur middel van induktiewe en deduktiewe beredenering. Aangesien professionele verpleegkundiges kennis moet dra van algemene riglyne om spesifieke riglyne te kan toepas, is die riglyne in twee kategorieë verdeel: Algemene riglyne en Spesifieke bloedprodukte riglyne. Deur hierdie studie in twee verskillende omgewings, naamlik privaat- en publieke instansies te doen, en 10 eenhede van een area (Gauteng) in Suid- Afrika daarby te betrek, sowel as om ’n relatief groot steekproef te gebruik, is die oordraagbaarheid van die uitkoms van die studie na ander streke verhoog. Die navorser het aanbeveel dat verdere studies oor dieselfde onderwerp gedoen word, en die uitkomste daarvan vergelyk word met die resultaat van hierdie studie. Die uitkoms die studie sal dan meer oordraagbaar wees na ander streke in Suid-Afrika. Die uitgebreide literatuuroorsig, die betrokkenheid van kundiges en die navorser se eie ondervinding en kennis in die neonatale intensiewe sorgverpleegkunde, het bygedra tot die vertrouenswaardigheid van die studie. Kundiges op die gebied van neonatale verpleegkunde en bloedtransfusie was betrokke, sowel as ’n biostatistikus verbonde aan die Universiteit van Pretoria. Etiese beginsels is gevolg. Die navorser was nie bewus van, en is ook nie gekonfronteer met enige etiese dilemmas of probleme tydens die studie nie. Konfidensialiteit is deurgaans gehandhaaf in die studie deurdat geen name van die deelnemers of hospitale genoem is nie. Alle inligting met betrekking tot die studie is aan die relevante partye verstrek en die deelnemers het almal uit eie vrye wil ’n ingeligte toestemmingsvorm onderteken. Toestemming om die studie te doen is ook verkry van die genomineerde hospitale se bestuur. Toestemming om die studie te doen is verkry van die Etiese Komittee van die Fakulteit van Gesondheidswetenskappe, Universiteit van Pretoria. Daar was geen risiko’s betrokke aan die studie nie, slegs voordele, aangesien die doel van die studie was om die professionele verpleegkundiges in die neonatale intensiewe sorgeenhede behulpsaam te wees met besluitneming rakende die gebruik van bloedprodukfilters tydens transfusie van bloed of bloedprodukte aan ’n neonaat. Die bevindings van die studie is bedoel om die kliniese praktyk van verpleging in neonatale intensiewe sorgeenhede te verbeter. Gevolglik word ’n aanbeveling gemaak dat hierdie riglyne geïmplimenteer word in neonatale intensiewe sorgeenhede, opleidingsinstansies sowel as die Suid-Afrikaanse Bloedoortappingsdiens. / Dissertation (MCur)--University of Pretoria, 2011. / Nursing Science / unrestricted
63

An in vitro study on the immunotoxicity of sewage effluents discharged into the Eerste River-Kuils river water catchment system

Magcwebeba, Tandeka January 2008 (has links)
Magister Scientiae - MSc / "The aim of the study was to use in vitro human whole blood cultures to screen the water samples collected from the Eerste/Plankenbrug river system for cytotoxicity and inflammatory activity and for the first time investigate the impact on the cell- mediated and humoral immune pathways. Water samples were collected fronm the sites during the dry summer season and rainy winter season. Blood was collected from the healthy male volunteers and diluted with RPMI 1640. For cytotoxicity and inflammatory activity 2.5ul of blood for 18-20 hrs at 37 C... This study shows that waster from the Plankenbrug River is heavily polluted by contaminants from both the agricultural area and informal settlement of Kayamandi. These contaminants can be potentially immunotoxic during the summer season and they can result in inflammatory diarrheal disease and immunosuppression in exposed individuals..."
64

Evaluation of Storage Conditions for Assessing DNA Damage Using the Comet Assay

Villavicencio, Dante 02 November 2006 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / The single cell gel electrophoresis assay (comet assay) is a useful tool for monitoring individuals who may be at risk of DNA damage and the ensuing process of carcinogenesis or other disease states. Leukocytes in blood samples provide a means of obtaining cells for use in the comet assay. However instances may arise when samples must be stored for later analysis. The present study investigated the effects of storage conditions on DNA damage in the form of strand breaks and oxidized bases in rat and human leukocytes using the comet assay. Whole blood and buffy coat samples were stored at room temperature or 4ºC for 1, 2, 24, and 48 hours or cryopreserved at -80ºC for 1 day and 1, 2, 3, and 4 weeks. The results show that the time of storage is limited if the whole blood or buffy coat samples are stored at room temperature or 4ºC. However, if cryopreserved using glycerol or DMSO as the cryoprotectant, the samples may be stored for at least 4 weeks without DNA strand breaks or oxidative damage deviating significantly from the fresh samples.
65

Novel electrochemical aptamer-based sensing mechanism inspired by selection strategies

Lyalina, Tatiana 01 1900 (has links)
Des millions de patients souffrant d’insuffisance cardiaque bénéficieraient d’analyses sanguines hebdomadaires pour surveiller l’évolution de leur état de santé comme c’est le cas avec les personnes atteintes du diabète. Cependant, il n’existe pas de technologies d’analyses sanguines rapides et efficaces pour détecter des marqueurs d’insuffisance cardiaque, telle que la créatinine, la NT-proBNP et la troponine I par exemple. La possibilité pour les patients de surveiller leurs taux de créatinine régulièrement, du confort de chez soi, améliorerait largement leur qualité de vie ainsi que leur taux de survie. En suivant leur taux de créatinine, le patient pourrait prédire des signes d’insuffisance cardiaque, et ainsi faire ajuster leur plan de traitement en conséquence. Pour y arriver, les biocapteurs électrochimiques, dont un exemple est le glucomètre, représentent une classe prometteuse de dispositifs d’analyse sanguine puisqu’ils sont faciles à utiliser, rapides, peu coûteux, sensibles, stables et potentiellement universels. Les biocapteurs électrochimiques à base d’ADN pourraient potentiellement être adaptés en biocapteur de créatinine, par l’entremise d’aptamères. Le but de cette recherche est de développer un nouveau mécanisme de détection universel et efficace pouvant être adapté directement à partir des stratégies de sélection des aptamères. Pour ce faire, nous avons identifié et caractérisé un élément de bioreconnaissance sélectif pour la créatinine. Ensuite, nous avons conçu une nouvelle stratégie de détection et nous avons validé cette nouvelle stratégie par spectroscopie de fluorescence avant de l’adapter pour une détection électrochimique. Par la suite, nous avons optimisé les performances du biocapteur en modulant des paramètres analytiques tels que sa gamme linéaire et son gain de signal, tout en validant ses performances dans une matrice complexe comme le sérum. Les résultats de cette recherche suggèrent que la stratégie de conception du nouveau biocapteur électrochimique à base d’aptamère est prometteuse pour la détection efficace de biomarqueurs sanguins. Ce type de mécanisme pourrait être facilement adapté pour détecter d'autres molécules cliniquement pertinentes en modifiant simplement la stratégie de sélection de l'aptamère. / Millions of patients suffering from heart failure would greatly benefit from weekly blood analysis to help them manage their disease state like patients suffering from diabetes. However, no simple blood monitoring technologies detecting heart failure biomarkers, such as creatinine, NT-proBNP, and troponin I, are available. The ability to determine and regularly monitor the creatinine level in the home setting would greatly improve the patient’s quality of life and survival rate. Knowing the concentration of creatinine help to predict heart failure and to revise the treatment plan if the concentration of creatinine is abnormal. To achieve this, electrochemical sensors, like a glucometer, represent a promising class of blood analysis devices due to their ease of use, fast response, low cost, inherent sensitivity and stability, and potential universality. More specifically, DNA-based electrochemical biosensors could potentially be adapted into a creatinine sensor by using aptamers specific to a biomarker. To achieve this goal, we identified a selective biorecognition element for creatinine detection and characterized it. We also designed a novel sensing aptamer-based strategy and validated this strategy by fluorescent spectroscopy before transposing it into the electrochemical format. We then optimized the performance of the sensor by tuning its signal gain and characterizing the dynamic range while also validating its performance in serum. The results of this work suggest that the electrochemical aptamer-based strategy represents a promising sensing mechanism. We believe this mechanism could be easily adapted to detect other clinically relevant molecules by simply relying on the aptamer’s selection strategy.
66

Analysis of Porcine Pro- and Anti-Inflammatory Cytokine Induction by S. suis In Vivo and In Vitro

Hohnstein, Florian S., Meurer, Marita, de Buhr, Nicole, von Köckritz-Blickwede, Maren, Baums, Christoph G., Alber, Gottfried, Schütze, Nicole 21 April 2023 (has links)
Weaning piglets are susceptible to the invasive Streptococcus (S.) suis infection, which can result in septicemia. The aim of this study was to investigate the cytokine profile induced upon S. suis infection of blood, to determine the cellular sources of those cytokines, and to study the potential effects of the induced cytokines on bacterial killing. We measured TNF-α, IL-6, IFN-γ, IL-17A and IL-10 after an experimental intravenous infection with S. suis serotype 2 in vivo, and analyzed whole blood, peripheral blood mononuclear cells (PBMC) and separated leukocytes to identify the cytokine-producing cell type(s). In addition, we used a reconstituted whole blood assay to investigate the effect of TNF-α on bacterial killing in the presence of different S. suis-specific IgG levels. An increase in IL-6 and IL-10, but not in IFN-γ or IL-17A, was observed in two of three piglets with pronounced bacteremia 16 to 20 h after infection, but not in piglets with controlled bacteremia. Our results confirmed previous findings that S. suis induces TNF-α and IL-6 and could demonstrate that TNF-α is produced by monocytes in vitro. We further found that IL-10 induction resulted in reduced secretion of TNF-α and IL-6. Rapid induction of TNF-α was, however, not crucial for in vitro bacterial killing, not even in the absence of specific IgG.
67

Effects of Graphene Oxide in vitro on DNA Damage in Human Whole Blood and Peripheral Blood Lymphocytes from Healthy individuals and Pulmonary Disease Patients: Asthma, COPD, and Lung Cancer

Amadi, Emmanuel E. January 2019 (has links)
For the past few decades, the popularity of graphene oxide (GO) nanomaterials (NMs) has increased exceedingly due to their biomedical applications in drug delivery of anti-cancer drugs. Their unique physicochemical properties such as high surface area and good surface chemistry with unbound surface functional groups (e.g. hydroxyl - OH, carboxyl /ketone C=O, epoxy/alkoxy C-O, aromatic group C=C, etc) which enable covalent bonding with organic molecules (e.g. RNA, DNA) make GO NMs as excellent candidates in drug delivery nanocarriers. Despite the overwhelming biomedical applications, there are concerns about their genotoxicity on human DNA. Published genotoxicity studies on GO NMs were performed using non-commercial GO with 2-3 layers of GO sheets, synthesized in various laboratories with the potential for inter-laboratory variabilities. However, what has not been studied before is the effects of the commercial GO (15-20 sheets; 4-10% edge-oxidized; 1 mg/mL) in vitro on DNA damage in human whole blood and peripheral blood lymphocytes (PBL) from real-life patients diagnosed with chronic pulmonary diseases [asthma, chronic obstructive pulmonary disease (COPD), and lung cancer], and genotoxic endpoints compared with those from healthy control individuals to determine whether there are any differences in GO sensitivity. Thus, in the present study, we had characterized GO NMs using Zetasizer Nano for Dynamic Light Scattering (DLS) and zeta potential (ZP) in the aqueous solution, and electron microscopy using the Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) in the dry state, respectively. Cytotoxicity studies were conducted on human PBL from healthy individuals and patients (asthma, COPD, and lung cancer) using the Methylthiazolyldiphenyl-tetrazolium bromide (MTT) and Neutral Red Uptake (NRU) assays, respectively. The genotoxicity (DNA damage) and cytogenetic effects (chromosome aberration parameters) induced by GO NMs on human whole blood from healthy individuals and patients were studied using the Alkaline Comet Assay and Cytokinesis-blocked Micronucleus (CBMN) assay, respectively. Our results showed concentration-dependent increases in cytotoxicity, genotoxicity, and chromosome aberrations, with blood samples from COPD and lung cancer patients being more sensitive to DNA damage insults compared with asthma patients and healthy control individuals. Furthermore, the relative gene and protein expressions of TP53, CDKN1A/p21, and BCL-2 relative to GAPDH on human PBL were studied using the Reverse Transcription Quantitative Polymerase Chain Reaction (RT-qPCR) and Western Blot techniques, respectively. Our results have shown altered gene and protein expression levels. Specifically, GO-induced cytotoxicity, genotoxicity, and micronuclei aberrations were associated with TP53 upregulation - a biomarker of DNA damage - in both patients and healthy individuals. These effects show that GO NMs have promising roles in drug delivery applications when formulated to deliver drug payload to COPD and cancer cells. However, the fact that cytotoxicity, genotoxicity, chromosome instability, and gene/protein expressions - biomarkers of cancer risk - were observed in healthy individuals are of concern to public health, especially in occupational exposures at micro levels at the workplace.
68

A Sample-to-Answer Polymer Lab-on-a-Chip with Superhydrophilic Surfaces using a Spray Layer-by-Layer Nano-Assembly Method

Lee, Kang Kug January 2013 (has links)
No description available.
69

<b>TOWARDS QUANTITATIVE MOLECULAR ISOTHERMAL AMPLIFICATION FOR POINT-OF-CARE HIV VIRAL LOAD MONITORING</b>

Emeka Nwanochie (18320661) 22 April 2024 (has links)
<p dir="ltr">Since the beginning of the HIV/AIDS epidemic, 85.6 million people worldwide have become infected with HIV; more than half of whom have died from AIDS-related complications.[1] Sustained viral suppression below the clinically relevant threshold (1000 copies per mL) with highly active antiretroviral therapy (HAART) has proven effective at managing and prolonging the life expectancy of people living with HIV (PLHIV). However, in 2022, 11.3 million PLHIV had still not achieved viral suppression and may become susceptible to both HIV transmission and a variety of opportunistic infections. Of particular importance is the complex issue of patient non-compliance in global HIV management due to social, economic, behavioral, and healthcare access barriers, potentially disconnecting many PLHIV from the HIV care continuum. Therefore, to boost patient engagement in clinical care and to improve overall patient outcomes, new approaches to viral load monitoring practices need to be developed to increase access, particularly in regions of high HIV prevalence.</p><p dir="ltr">Nucleic acid amplification tests (NAATs) have emerged as potent tools for monitoring viral load, with reverse transcription quantitative polymerase chain reaction (RT-qPCR) being recognized as the benchmark due to its sensitivity and ability for real-time quantification enabled by fluorescence signal emission. Nevertheless, RT-qPCR is burdened by drawbacks including extended processing times, high operational costs, and the requirement for specialized laboratory facilities. In this study, we propose a novel method for HIV-1 viral load monitoring by integrating reverse-transcriptase loop-mediated isothermal amplification (RT-LAMP) with real-time particle diffusometry (PD). This approach allows for the continuous monitoring of changes in the diffusion of 400 nm fluorescent particles during RT-LAMP amplification, targeting the <i>p24</i> gene region of HIV-1 RNA. This enables the real-time detection of amplification curves, achieving a detection sensitivity in water samples as low as 25 virus particles per μL within a short duration of 30 minutes. Additionally, to address challenges related to amplification inhibition in complex human specimens, we developed a power-free sample processing system specifically designed for extracting HIV-1 RNA from both whole blood and plasma.Top of FormBottom of FormThis system modifies a commercially available spin-column protocol by integrating a syringe device and handheld bulb dryer, thus eliminating the requirement for a centrifuge. The adaptation allows for the completion of the entire extraction procedure, encompassing viral lysis, RNA capture, washing, and elution of purified HIV-1 RNA, within a timeframe of less than 16 minutes. Subsequent analyses, including RT-LAMP and RT-qPCR, demonstrate a limit of detection of 100 copies per μL and an average RNA recovery of 32% (for blood) and 70% (for plasma) in the elution fraction. Further investigations emphasize the significant presence of purified RNA in the spin column volume (termed as dead volume), and the cumulative recovered RNA copies align with those obtained using the gold standard centrifugation extraction method. Ultimately, we incorporated the real-time quantitative PD-RT-LAMP assay onto a field-compatible handheld portable platform suitable for field use, featuring built-in quality control measures. This platform enables sample-to-answer viral load testing near the point of care (POC). Subsequently, we undertook essential preparatory steps, such as reagent drying to obviate the need for cold storage, initial device calibration, and hands-on training of laboratory personnel regarding device operation, to validate device performance within a cohort of individuals living with HIV (PLHIV). These innovations facilitate quick and comprehensive viral load determination, offering promise for enhanced HIV management and patient care</p>
70

Release kinetics of tumor necrosis factor-α and interleukin-1 receptor antagonist in the equine whole blood

Rütten, Simon, Schusser, Gerald F., Abraham, Getu, Schrödl, Wieland 21 June 2016 (has links) (PDF)
Background: Horses are much predisposed and susceptible to excessive and acute inflammatory responses that cause the recruitment and stimulation of polymorphnuclear granulocytes (PMN) together with peripheral blood mononuclear cells (PBMC) and the release of cytokines. The aim of the study is to develop easy, quick, cheap and reproducible methods for measuring tumor necrosis factor alpha (TNF-α) and interleukin-1 receptor antagonist (IL-1Ra) in the equine whole blood cultures ex-vivo time- and concentration dependently. Results: Horse whole blood diluted to 10, 20 and 50 % was stimulated with lipopolysaccharide (LPS), PCPwL (a combination of phytohemagglutinin E, concanavalin A and pokeweed mitogen) or equine recombinant TNF-α (erTNF-α). TNF-α and IL-1Ra were analyzed in culture supernatants, which were collected at different time points using specific enzyme-linked immunosorbent assays (ELISA). Both cytokines could be detected optimal in stimulated 20 % whole blood cultures. TNF-α and IL-1Ra releases were time-dependent but the kinetic was different between them. PCPwL-induced TNF-α and IL-1Ra release was enhanced continuously over 24–48 h, respectively. Similarly, LPS-stimulated TNF-α was at maximum at time points between 8–12 h and started to decrease thereafter, whereas IL-1Ra peaked later between 12–24 h and rather continued to accumulate over 48 h. The equine recombinant TNF-α could induce also the IL-1Ra release. Conclusions: Our results demonstrate that similar to PCPwL, LPS stimulated TNF-α and IL-1Ra production time-dependently in whole blood cultures, suggesting the suitability of whole blood cultures to assess the release of a variety of cytokines in health and diseases of horse.

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