<p><span style="font-size: 11.5pt">The blood-brain barrier (BBB) is an interface between the brain parenchyma and the circulating system. This barrier plays a vital role in protecting the CNS by restricting free paracellular diffusion of molecules from the systemic circulation. Methamphetamine (MA) is a highly addictive psychostimulant and has demonstrated neurotoxic properties as well as the ability to compromise the BBB. MA exposure is strongly linked with increased oxidative stress which can result in a decrease in the integrity of the BBB. </span></p> <div><span style="font-size: 11.5pt">The aim of this study was to investigate <i>in vitro </i>effects of pure and street MA &ldquo / tik&rdquo / on DNA proliferation and cell cycles in mouse brain endothelial (bEnd5) cells. </span></div> <div><span style="font-size: 11.5pt">Trypan blue was used to determine effects of MA (0.0001M-1mM) on cell viability and % cell growth. The Cell Titer Glo&reg / luminescent assay and nonradioactive analogue, 5-bromo-2'-deoxyuridine (BrdU) was used to detect ATP and DNA levels, respectively. Cell cycles (propidium iodide incorporation) were analysed using flow cytometry. Statistical analysis was performed using Wilcoxin Rank Sum Test in which P&lt / 0.05 was denoted as significant. </span></div> <div><span style="font-size: 11.5pt">Results of this study showed that: </span></div> <div><span style="font-size: 11.5pt">1. Viability of bEnd5 cells exposed to all selected concentrations of MA were unaffected when compared to controls (P&gt / 0.05)&nbsp / </span><span style="font-size: 11.5pt">&nbsp / </span></div> <div><span style="color: windowtext / font-size: 11.5pt">2. % Cell growth was suppressed by MA exposure at 96hrs in comparison to that of controls (P&le / 0.03). </span></div> <div style="margin: 0cm 0cm 25pt"><span style="color: windowtext / font-size: 11.5pt">3. Cells exposed to MA had significant higher ATP concentrations than control cells at 96hrs (P &le / .0.03) </span><span style="color: windowtext / font-size: 11.5pt">4. DNA synthesis was markedly suppressed in cells exposed to pure MA and street MA sample 4 (P&le / 0.03), while was similar and higher in cells exposed to street MA sample 1 (P=0.39), and street MA sample 2 and 3 (P&le / 0.04), respectively at 96hrs. </span><span style="color: windowtext / font-size: 11.5pt">5. bEnd5 cell were arrested between 72 and 96hrs at the G1-S phase.&nbsp / </span></div> <div style="margin: 0cm 0cm 25pt"><span style="line-height: 115% / font-size: 11.5pt">In conclusion, this study demonstrated pure and illicit samples of MA obtained from forensic police did not affect the viability of bEnd5 cells, however resulted in the significant suppression of their cell numbers. This growth inhibition may be due to MA-induced cell cycle arrest at the G1-S phase. The study also showed that compounds found in the samples of street MA produced results significantly different to that of pure MA.</span></div>

The limited success of HIV vaccine candidates to date highlights our need to better characterize protective cell-mediated immunity. Understanding correlates CD8+ T cell protection against HIV infection and progressive disease is essential for informing effective vaccine development, design and evaluation. CD8+ T cell responses with a robust polyfunctional and proliferative component are strongly linked to better disease outcomes. However, the specificity of polyfunctional and proliferative CD8+ T cell responses has not been thoroughly investigated. Additionally, the specificity of memory subsets and their connection to polyfunctionality and proliferation responses has not been adequately assessed. We address these gaps in knowledge and provide a better understanding of the fine specificity of HIV-specific CD8+ T cell responses. We hypothesize that the epitopes recognized by central memory (TCM) and effector memory (TEM) CD8+ T cells, defined by functional attributes, differ in chronic HIV-1 infection. Additionally, we hypothesize that polyfunctional and proliferative responses will better correlate with protection in HIV disease progression. The qualities of CD8+ T cell responses were evaluated using polyfunctional flow cytometry measuring both functional and phenotypic attributes of both TEM and TCM subsets in HIV infected individuals. We evaluated the quality and evolution of CD8+ T cell responses in HIV infected individuals shortly after seroconversion through to the chronic phase of infection, finding that early polyfunctional responses may result in better HIV disease outcomes. Additionally, we show that epitope-specificity differs between short-term cytokine/chemokine secretion and long-term proliferative assays. Importantly, we show that, at a cohort level, particular epitopes preferentially elicit specific qualities of CD8+ T cell responses in preference to others. This research improves our understanding of HIV pathogenesis and indicates that we can identify specific epitopes that can elicit protective responses and that early polyfunctional responses may slow HIV disease progression. Understanding the polyfunctional and proliferative capacities of HIV-specific effector and memory cells at various stages of HIV infection is of critical importance to the design of vaccines intended to elicit protective cell-mediated responses.

The cell cycle is a highly complex process that is under the control of several pathways.  Failure to regulate and/or complete the cell cycle often leads to cell cycle arrest, which may be followed by programmed cell death (apoptosis). One cell type that has a variety of unique cell cycle properties is the horizontal cell of the chicken retina. In this thesis we aimed to characterize the final cell cycle of retinal horizontal cells. In addition, the regulation of the cell cycle and the resistance to apoptosis of retinal horizontal cells are investigated. Our results show that the final cell cycle of Lim1-expressing horizontal progenitor cells is heterogenic and three different cell cycle behaviors can be distinguished. The horizontal cells are generated by: (i) an interkinetic nuclear migration with an apical mitosis; (ii) a final cell cycle with an S-phase that is not followed by mitosis, such cells remain with a fully or partially replicated genome; or (iii) non-apical (basal) mitoses. Furthermore, we show that the DNA damage response pathway is not triggered during the heterogenic final cell cycle of horizontal progenitor cells. However, chemically induced DNA damage activated the DNA damage response pathway without leading to cell cycle arrest, and the horizontal progenitor cells entered mitosis in the presence of DNA damage. This was not followed by apoptosis, despite the horizontal cells being able to functionally activate p53, p21CIP1/waf1, and caspase-3. Finally, we show that FoxN4 is expressed in horizontal progenitor cells and is required for their generation. Over-expression of FoxN4 causes cell death in several neuronal retinal cell types, except horizontal cells, where it results in an overproduction. In conclusion, in this thesis, a novel cell cycle behavior, which includes endoreplication not caused by DNA damage and a basal mitosis that can proceed in the presence of DNA damage, is described. The cell cycle and cell survival processes are of particular interest since retinal horizontal cells are suggested to be the cell-of-origin for retinoblastoma.

A thorough understanding of beta-cell proliferation, function, death and regeneration under normal condition as well as in the progression of diabetes is crucial to the conquest of this disease. The work presented in this thesis aimed to investigate the expression and role of a novel transcription factor, Zinc finger BED domain-containing protein 6 (ZBED6), in beta-cells. ZBED6 was present in mouse βTC-6 cells and human islets as a double nuclear band at 115/120 kDa and as a single cytoplasmic band at 95-100 kDa, which lacked N-terminal nuclear localization signals. Lentiviral shRNA-mediated stable silencing of ZBED6 in βTC-6 cells resulted in altered morphology, decreased proliferation, a partial S/G2 cell cycle arrest, increased expression of beta-cell specific genes, and higher rates of apoptosis. ChIP sequencing of human islets showed that ZBED6 binding was preferentially to genes that control transcription, macromolecule biosynthesis and apoptosis. We proposed that ZBED6 supported proliferation and survival of beta-cells, possibly at the expense of specialized beta-cell function, i.e. insulin production. To further investigate the role of ZBED6 in beta-cells, ChIP sequencing and whole transcriptome analysis were performed using MIN6 cells. More than 4000 putative target genes of ZBED6 were identified, including Pdx1, MafA and Nkx6.1. ZBED6-silencing resulted in differential expression of more than 700 genes, which was paralleled by an increase in the content and release of insulin in response to a high glucose concentration. Altered morphology/growth patterns as indicated by increased cell clustering were observed in ZBED6 silenced cells. We found also that ZBED6 decreased the ratio between N- and E-cadherin. A lower N- to E-cadherin ratio may hamper the formation of three-dimensional beta-cell clusters and cell-to-cell junctions with neural crest stem cells, and instead promote efficient attachment to a laminin support and monolayer growth. Thus, by controlling beta-cell adhesion and cell-to-cell junctions, ZBED6 might play an important role in beta-cell differentiation, proliferation and survival.

Current revolutions in biotechnology and neuroscience are changing military technologies, necessitating dramatic re-evaluations in arms regulatory regimes. This study assesses how these new technologies can be used in weapons systems - by governments and terrorists alike - and whether this frightening development can be brought under effective international control. Malcolm Dando begins by surveying the existing (and arguably inadequate) control mechanisms for chemical and biological weapons. He then discusses how earlier generations of toxin and bioregulatory weapons have been used by such states as Iraq, the Soviet Union and the USA, and explains, in non-technical terms, the implications for new weapons technology. Considering how international law might be applied to constrain undesirable military developments without restricting technological developments for peaceful purposes, Dando concludes with a proposal for an integrated control regime that would link international agreements, national legislation, and trade regulations.

In November 2013, the Islamic Republic of Iran reached an interim agreement with six world powers, including the United States. After the agreement was implemented in January 2014, Iran froze uranium enrichment in exchange for limited sanctions relief from the United States. This was the first diplomatic exchange between the United States and Iran in over thirty years. Keeping Iran from the Bomb analyzes how each country’s respective domestic politics and stereotypes of the other have, until recently, impeded diplomacy between the two nations. This study examines American-Iranian relations during the hostage crisis, the Bush administration, and the Obama administration to do the following: analyze what has prevented diplomacy in the past, explain the circumstances that made the interim agreement possible, and show what factors threaten this diplomatic progress. The primary argument of this thesis is that the leaders of both the United States and Iran are encouraged, and often rewarded, by various entities to demonize the other nation. If the leaders of the United States and Iran can convince their domestic constituents that continued cooperation with the other country will be beneficial, diplomacy can move forward.

Hematopoietic stem/progenitor cells (HSPC) play main role in constituting the whole hematopoietic system. Furthermore, since recognized in 1960s, HSPC are utilized to protect patients from severe chemo and radio therapy. As time goes, they are also used to treat hematopoietic disorders such as leukemia. Bone marrow, peripheral blood and umbilical cord blood are now the three sources of HSPC. Umbilical cord blood seems optimal because it is easy to obtain, no risk to graft donor and low probability of infection transmission. However, low number of HSPCs in umbilical cord blood is the main limitation. My research focuses mainly on in-vitro proliferation of HSPCs. In addition, I also worked on labeling HSPC in-vitro for tracking these cells after transplantation. The experimental results indicated that HSPCs are effectively labeled and their proliferation rate is significantly enhanced in-vitro. / N/A

No description available.

Thesis (Ph. D.)--University of Hong Kong, 2007. / Also available online.

Universiẗat, Diss., 2007--Frankfurt (Main).