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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.
51

The Effect of K562-IL21-2 Plasma Membrane Particles on the Proliferation of Natural Killer Cells to Fight Cancer

Prophete, Michelle 01 January 2017 (has links) (PDF)
Immunotherapy has emerged as a current and future paradigm of cancer treatment, which utilizes the body’s immune system to eradicate cancer. Natural Killer (NK) cells as part of the innate immune system have immense potential in their anti-tumor cytotoxic activities and host cell surveillance properties. NK cells comprise approximately five to fifteen percent of peripheral blood lymphocytes and can be proliferated in vitro using recently developed methods with co-cultures with feeder cells (derived from engineered tumor cells) or plasma membrane (PM) particles, produced from the fore mentioned feeder cells, in combination with soluble cytokines. For efficient growth and maintenance of these NK cells, Interleukin-2 (IL-2) is utilized. IL-2 in solution, through receptor mediated signaling, stimulates proliferation of T-cells and NK cells. NK cells have lower responsiveness to IL-2 and consequently require a larger systemic dose to stimulate them as opposed to competing cell populations that have higher expression of receptors for IL-2, such as T-cells, which can have the effect of lower effective stimulation of NK cell growth. Such difference in the stimulatory capability of IL-2 toward NK cells and the short circulation lifetime of soluble IL-2 require higher dosages of soluble IL-2 for effective in vivo NK cell proliferation for therapeutic application against cancer, but is toxic. Therefore establishing another form of IL-2 delivery that improves its specific targeting to NK cells would be beneficial and may be crucial for novel therapeutic improvement. The Copik Laboratory has made an IL-2 fusion protein construct having a membrane anchor for expression of membrane-bound IL-2 on K562-41bbl-21 cells (K562-IL21). K562-IL21 cells are selectively recognized by NK cells and stimulate their proliferation and cytotoxicity. Hence, a K562-IL21 membrane–bound IL-2 form should be targeted to NK cells with IL-2 delivery. K562-IL21-2 cells were then used to prepare PM21-2 particles which have the potential to provide NK cell targeted, long-lived form of IL-2 for use as an injectable drug for in vivo adjuvant stimulation of NK cells. The presence of IL-2 on the in the PM21-2 particle product was verified by Western blot, and ELISA. Particle preparations from the modified K562 cells should possess characteristics that allow them to possibly replace soluble IL-2 and more specifically increase the numbers or anti-tumor activity of NK cell populations. The effect of PM21-2 particles was studied in in vitro culture based experiments, which tested the effectiveness the PM21-2 particles to induce selective NK cells expansion as compared to PM21 particles in the presence or absence of soluble IL-2.
52

Neurocorrelates of the Mirror Neuron System in Children with Chromosome 22q11.2 Deletion Syndrome

Marais, Ade 20 December 2017 (has links)
Activation of brain regions that make up the mirror neuron system (MNS) is thought to reflect processing and perceiving behavior, action, and intentionality of other organisms. Sensing and perceiving motor behavior in others is an important component of understanding and participating in social interactions. Children with chromosome 22q11.2 deletion syndrome (22q11.2DS) are diagnosed with serious medical, cognitive, and socio-emotional symptoms. Atypical development and function of the MNS may underpin some aspects of socio-emotional impairment and autism spectrum disorder (ASD)-like symptomology reported. This study of the MNS investigates differences in activation in the operculum, sensorimotor areas, and basal ganglia (BG) in children with 22q11.2DS compared to typically-developing (TD) controls. Twenty-nine children (22q11.2DS: n=15; TD: n=16) between ages 7-16 viewed videos of a human hand manipulating various household objects during a functional magnetic resonance imaging (fMRI) scan. In Analysis 1, children with 22q11.2DS had less extensive brain activation than TD children in the operculum, sensorimotor areas, and BG. In Analysis 2, children with 22q11.2DS had the same results as Analysis 1 with the exception of sensorimotor areas not being highly active in either group. In both analyses, fMRI signal change from baseline to video did not differ significantly between groups. Processing efficiency in children with 22q11.2DS may be lower or more variable when compared to TD peers. This is the first study comparing children with 22q11.2DS to TD peers specifically looking at MNS activation within the operculum region to assess higher cognitive functioning, somatosensory cortex for sensory interpretation, and basal ganglia for gross motor activity. Future studies should compare brain activation between children with ASD and those with 22q11.2DS during an MNS task as the next step to further clarify the origin of ASD symptoms reported in this population.
53

Illumination of the Golgi apparatus of Pathogenic and Nonpathogenic Naegleria species

Poe, Tyler M, Marciano-Cabral, Francine 01 January 2019 (has links)
In this study, Naegleria fowleri, a pathogenic amoeba and the causative agent of Primary Amebic Meningoencephalitis (PAM), was utilized to determine the presence or absence of classically conserved Golgi molecules featured in the expression of a Golgi apparatus. Previous studies concluded no Golgi expression via light microscopy and transmission electron microscopy, but a recent report on Naegleria gruberi indicated the presence of dispersed Golgi tubules. Non-pathogenic species of the Naegleria genus such as Naegleria gruberi 30540 and Naegleria lovaniensis 30569 were utilized in Western immunoblot analysis compared to reduced whole-cell lysate proteins of two strains of N. fowleri and Vero CCL-81, Chlorocebus sp. kidney epithelial cells, which were utilized as a positive control for Golgi expression. N. fowleri and N. lovaniensis whole-cell lysates had indications of a 110 kDa reduced protein, associated with the predicted molecular weights of the beta-COPI subunit of the COPI cis-Golgi vesicular transport complex with further Western immunoblot indication of a weak band around 25 kDa corresponding to rabbit polyclonal antibodies specific for ARF1. Serial Dilutions of Wheat Germ Agglutinin Alexa Fluor 488TM were performed on Vero cells, Naegleria fowleri 30894, and N. gruberi 30540 with 1:100 dilution of recommended stock dilution of WGA 488 determined for utilization in sequential immunofluorescence. Sequential immunofluorescence with Wheat Germ Agglutinin Alexa Fluor 488TM and then blocked with 3% BSA:PBS [wt/vol] dilution with subsequent incubation in rabbit anti-beta-COPI primary 1:250, and 1:1000 of Alexa Fluor 594 goat anti-rabbit secondary antibody exposure showed strong indications of organized cis- and trans-punctate Golgi body markers in close association in individual and dividing cells of Naegleria fowleri and conserved Golgi expression in the positive control Vero cells, but further experiments are necessary to verify this finding with N. fowleri.
54

Investigation and prosecution of transnational women trafficking: the case of Ethiopia

Beyene, Selam Gebretsion January 2011 (has links)
<p>Human trafficking is a widespread and growing crime in the world. Trafficking by its nature involves movement from one place to another and in most cases, it comprises crossing international borders. Although the estimation of victims of trafficking stretches to 2 450 000, the number of prosecutions is less than 5 000. This indicates the challenges faced by many countries in the investigation and prosecution of trafficking cases. Transnational human trafficking is committed in different places, making investigation and prosecution very complex. This paper examines how investigation and prosecution can be carried out when the criminal acts are committed in different countries. It also examines how the issue of jurisdiction is entertained. Furthermore, it addresses who can be termed as &ldquo / traffickers&rdquo / in dealing with human trafficking issues. Ethiopia is facing a big problem in fighting human trafficking. Like most countries, the issue of human trafficking is closely related to women. Ethiopia uses the criminal justice system as a tool to eradicate women trafficking. The investigation and prosecution of trafficking cases face many problems which have a direct impact on the country‟s efforts to overcome human trafficking. Thus, this research will contribute significantly by highlighting deficits in the criminal justice system as it deals with the investigation and prosecution of women trafficking issues and by making recommendations with regards to them.</p>
55

Investigation and prosecution of transnational women trafficking: the case of Ethiopia

Beyene, Selam Gebretsion January 2011 (has links)
<p>Human trafficking is a widespread and growing crime in the world. Trafficking by its nature involves movement from one place to another and in most cases, it comprises crossing international borders. Although the estimation of victims of trafficking stretches to 2 450 000, the number of prosecutions is less than 5 000. This indicates the challenges faced by many countries in the investigation and prosecution of trafficking cases. Transnational human trafficking is committed in different places, making investigation and prosecution very complex. This paper examines how investigation and prosecution can be carried out when the criminal acts are committed in different countries. It also examines how the issue of jurisdiction is entertained. Furthermore, it addresses who can be termed as &ldquo / traffickers&rdquo / in dealing with human trafficking issues. Ethiopia is facing a big problem in fighting human trafficking. Like most countries, the issue of human trafficking is closely related to women. Ethiopia uses the criminal justice system as a tool to eradicate women trafficking. The investigation and prosecution of trafficking cases face many problems which have a direct impact on the country‟s efforts to overcome human trafficking. Thus, this research will contribute significantly by highlighting deficits in the criminal justice system as it deals with the investigation and prosecution of women trafficking issues and by making recommendations with regards to them.</p>
56

EBV-Specific CD4+ T Cell Responses in Acute Infectious Mononucleosis: a Dissertation

Precopio, Melissa Lynn 01 April 2004 (has links)
Epstein-Barr virus (EBV) is a ubiquitous herpesvirus that establishes a life-long latent infection of B cells. It is usually asymptomatic in healthy individuals; however, individuals with compromised immunity often develop EBV-induced lymphoma. EBV also encodes potential oncogenes that can contribute to tumorigenesis. Therefore, vaccine and immunotherapeutic strategies targeting EBV are desirable. Recent studies have shown that infusion of EBV-specific CD8+T cells can elicit remission of lymphomas arising after administration of immunosuppressive drugs during transplantation, suggesting an important role for T cells in the prevention of EBV-induced malignancy. A better understanding of the cellular immune components involved in the control of EBV will aid in the development of methods to prevent infection and/or treat EBV-associated disease. While EBV infection is usually acquired asymptomatically during childhood, primary infection of adolescents and young adults can result in an illness termed acute infectious mononucleosis (AIM). Because of the characteristic symptoms of the illness, individuals with AIM can be readily identified and diagnosed with acute EBV infection. Thus, primary CD4+ and CD8+ T cell responses against the virus can be evaluated. It has been previously found that there is a marked expansion of lytic EBV protein-specific CD8+ T cells early during AIM, with delayed detection of lower frequencies of latent EBV protein-specific CD8+ T cells. The magnitude and specificity of CD4+T cell responses during AIM has been less well characterized. This thesis dissertation presents data from both functional assays and direct staining experiments documenting the timing, magnitude, and antigen-specificity of CD4+ T cells over the course of primary EBV infection. Lytic and latent protein-specific CD4+ T cells were readily detected by intracellular IFN-γ production at presentation with AIM and declined rapidly thereafter. Blood EBV load was also quantitated and found to decrease over time following AIM. By contrast, CD8+T cell IFN-y responses remained high for several weeks following presentation with AIM. Direct staining of lytic epitope-specific CD4+ T cells during AIM revealed high frequencies of virus-specific cells with low proliferative and IFN-γ-producing potential. Blood EBV load in these patients was persistently high through 6 wk following AIM. These data suggest a relationship between high EBV load during acute infection and impaired EBV-specific CD4+ T cell responses, which are compatible with impaired CD4+ T cell responses reported during high viremia associated with other viral infections. This may represent a mechanism by which persistent viruses, such as EBV, are able to establish a life-long infection in their hosts.
57

Type-Specific Immunity in HIV-1 Vertically Infected Infants

Pikora, Cheryl A. 15 December 1995 (has links)
High frequencies of CTL recognizing laboratory strains of HIV-1 are present in HIV-1 infected adults as early as preseroconversion. The presence of HIV-1 specific CTL during primary infection has been correlated with better control of early viremia and a more delayed onset of CD4 lymphocyte loss. Previous experiments in our laboratory have demonstrated that, unlike HIV-1 infected adults, the majority of vertically infected infants lack CTL which recognize laboratory strains of HIV-1 within the first year of life. ADCC antibody responses against laboratory strains of HIV-1 env gene products are also delayed until at least two years of age. As a possible correlate, disease progression is also more rapid in vertically infected infants. We hypothesized that HIV-1-specific CTL are type-specific in early infancy and that the use of target cells expressing laboratory strain gene products might limit the detection of HIV-1-specific CTL. To address this hypothesis, HIV-1 env genes from early isolates of four infants were PCR amplified, cloned, and used to generate recombinant vaccinia vectors (vv). The frequencies of CTL precursors (CTLp) recognizing env gene products from autologous isolates and the IIIB strain of HIV-1 were measured at time points from early infancy to 19 months using limiting dilution analysis (LDA). ADCC titers were also measured against autologous and IIIB env gene products at 4 time points spanning 2 months to 2 years of age. CTL precursors from 3 of 4 of these patients were specific only for autologous HIV-1 env gene products during the first 6 to 12 months of age. A pattern of CTL responsiveness was observed in these 3 patients in which type-specific CTL precursors observed in early infancy were replaced by cross-reactive, group-specific CTL by 6 to 12 months of age. CTL precursors from a fourth patient at 12 months of age recognized IIIB env and 1 out of 2 envs derived from 2 autologous viral isolates. High titers titers of ADCC antibodies against autologous env were detected in two infants prior to the detection of ADCC antibodies to IIIB. In two other infants, group specific ADCC antibody responses were detected in late infancy. Our results demonstrate that young infants can mount HIV-1 specific CTL and ADCC responses. The ability of young infants to mount cellular immune responses to HIV-1 also provides support for the concept of perinatal vaccination to prevent HIV-1 transmission. Furthermore. the lack of broadly-reactive CTL in early infancy suggests that the use of vaccines based on laboratory strains of HIV-1 may not afford protection from vertical infection.
58

Maternally Derived Anti-Dengue Antibodies and Risk of DHF in Infants: A Case-Control Study

Hatch, Steven 01 August 2010 (has links)
This study proposes to directly test the hypothesis that antibody-dependent enhancement (ADE) is the critical factor in the development of dengue hemorrhagic fever (DHF) in infants. DHF occurs in two distinct clinical settings: a) in children and adults with secondary DENV infection, and b) in infants with primary DENV infection born to mothers with prior DENV infection. The ADE hypothesis proposes that pre-existing serotype-cross-reactive non-neutralizing anti-DENV antibodies bind the heterotypic DENV during secondary infection and enhance its uptake into immune cells, leading to increased viral load and DHF. This model suggests that DHF in DENV-infected infants is caused by the enhancing effect of waning maternal anti-DENV antibodies, thus causing a “physiologic secondary infection” during an infant’s primary infection and thereby increasing the infant’s risk for DHF. The effect of maternal immunity on DHF in infants has been studied exclusively in Southeast Asia. However, the maternal DENV seroprevalence approaches 100% in this part of the world. As a consequence, the ADE model of infant DHF cannot truly be tested in Southeast Asia, because all infants possess anti-DENV antibody at birth. In the Western Hemisphere, by contrast, women may have experienced either a single DENV infection, more than one DENV infection, or no DENV infection at all. The ability to include DENV-seronegative mothers as controls allows for the ADE hypothesis to be directly tested in a clinical study. To our knowledge, no such study has been previously conducted. This thesis presents a case-control study designed to evaluate the influence of positive maternal dengue seroprevalence on the risk of DHF in infants. As the MSCI program provides instruction in study design, this thesis does not present findings. The clinical trial described herein began in May 2010 and enrollment is expected to continue through May 2012 (see Table 4).
59

Investigation and prosecution of transnational women trafficking: the case of Ethiopia

Beyene, Selam Gebretsion January 2011 (has links)
Magister Legum - LLM / Human trafficking is a widespread and growing crime in the world. Trafficking by its nature involves movement from one place to another and in most cases, it comprises crossing international borders. Although the estimation of victims of trafficking stretches to 2 450 000, the number of prosecutions is less than 5 000. This indicates the challenges faced by many countries in the investigation and prosecution of trafficking cases. Transnational human trafficking is committed in different places, making investigation and prosecution very complex. This paper examines how investigation and prosecution can be carried out when the criminal acts are committed in different countries. It also examines how the issue of jurisdiction is entertained. Furthermore, it addresses who can be termed as “traffickers” in dealing with human trafficking issues. Ethiopia is facing a big problem in fighting human trafficking. Like most countries, the issue of human trafficking is closely related to women. Ethiopia uses the criminal justice system as a tool to eradicate women trafficking. The investigation and prosecution of trafficking cases face many problems which have a direct impact on the country‟s efforts to overcome human trafficking. Thus, this research will contribute significantly by highlighting deficits in the criminal justice system as it deals with the investigation and prosecution of women trafficking issues and by making recommendations with regards to them. / South Africa
60

Dissection of α6β4 Integrin-Dependent Signaling and Breast Carcinoma Invasion: A Dissertation

Yang, Xiaoqing 15 July 2011 (has links)
Breast cancer is one of the most prevalent cancers in the world. Each year, over 400,000 women die from breast cancer world wide and metastasis is the main cause of their mortality. Tumor cell invasion into the adjacent tissue is the first step in the multistep process of cancer metastasis and it involves multiple protein changes. The α6β4 integrin, a transmembrane heterodimeric laminin receptor is associated with poor prognosis in many tumor types, including breast cancer. Src family kinase (SFK) activity is elevated in many cancers and this activity also correlates with invasive tumor behavior. The α6β4 integrin can stimulate SFK activation and promote cancer invasion, however the mechanism by which it does so is not known. In the current study, I provide novel mechanistic insight into how the α6β4 integrin selectively activates the Src family kinase member Fyn in response to receptor engagement. Specifically, the tyrosine phosphatase SHP2 is recruited to α6β4 and its catalytic activity is stimulated through a specific interaction of its N-terminal SH2 domain with pY1494 in the β4 subunit. Importantly, both catalytic and non-catalytic functions of SHP2 are required for Fyn activation by α6β4. Fyn is recruited to the α6β4/SHP2 complex through an interaction with phospho-Y580 in the C-terminus of SHP2. In addition to activating Fyn, this interaction with Y580-SHP2 localizes Fyn to sites of receptor engagement, which is required for α6β4-dependent invasion. Moreover, the selective activation of Fyn, but not Src, requires the palmitoylation modification of Fyn on its N-terminus. Of clinical relevance, phospho-Y580-SHP2 and phospho-Y418-SFK could be used as potential biomarkers of invasive breast cancer because their expression are elevated in high-grade breast tumors.

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