Essay #1 – Factors influencing the risk of falls in the construction industry: a review of the evidence Falls are a significant public health risk and a leading cause of nonfatal and fatal injuries among construction workers worldwide. A more comprehensive understanding of casual factors leading to fall incidents is essential to prevent falls in the construction industry. However, an extensive overview of causal factors is missing from the literature. In this paper, 536 articles on factors contributing to the risk of falls were retrieved. One hundred twenty-one (121) studies met the criteria for relevance and quality to be coded, and were synthesized to provide an overview. In lieu of the homogeneity needed across studies to conduct a structured meta-analysis, a literature synthesis method based on macro-variables was advanced. This method provides a flexible approach to aggregating previous findings and assessing agreement across those studies. Factors commonly associated with falls included working surfaces and platforms, workers’ safety behaviors and attitudes, and construction structure and facilities. Significant differences across qualitative and quantitative studies were found in terms of focus, and areas with limited agreement in previous research were identified. Findings contribute to research on the causes of falls in construction, developing engineering controls, informing policy and intervention design to reduce the risk of falls, and improving research synthesis methods. Essay #2 – Review of quantitative studies of interventions for responding to infectious disease outbreaks We reviewed the modeling and retrospective literature on responding to outbreaks of infectious diseases in humans and animals. Unlike routine immunization and control efforts, outbreak response activities require rapid reactive actions to address an urgent or emergent situation. We focused our review on characterizing the types of diseases analyzed, the interventions used, and the models employed. Out of the 211 studies identified, we find that the majority focus on a few diseases (influenza, foot and mouth disease, smallpox, measles, and hepatitis). We identified 34 distinct interventions explored in these studies that fall under the general categories of vaccination, prophylaxis, quarantine/isolation, contact restriction, exposure reduction, killing/slaughtering, and surveillance. A large number of studies (141) use simulation/analytical models to analyze outbreak response strategies. We identify key factors contributing to the effectiveness of different interventions that target high-risk individuals, trace infected contacts, or use a ring to delineate geographical boundaries for an intervention. Essay #3 – Development of an individual-based model for polioviruses: implications of the selection of network type and outcome metrics We developed an individual-based (IB) model to explore the stochastic attributes of state transitions, the heterogeneity of the individual interactions, and the impact of different network structure choices on the poliovirus transmission process in the context of understanding the dynamics of outbreaks. We used a previously published differential equation-based model to develop the IB model and inputs. To explore the impact of different types of networks, we implemented a total of 26 variations of six different network structures in the IB model. We found that the choice of network structure plays a critical role in the model estimates of cases and the dynamics of outbreaks. This study provides insights about the potential use of an IB model to support policy analyses related to managing the risks of polioviruses and shows the importance of assumptions about network structure. / Ph. D.

A seizure is defined as an abnormal electrical discharge from the brain that results in the affected area losing its normal function and reacting uncontrollably. A particular subset of seizures, known as absence seizures, are characterized by brief, paroxysmal losses of consciousness that are associated with bilaterally synchronous 3 Hz spike and wave discharges (SWDs) on electroencephalography (EEG). The optimal way to understand any disease state is to study it within the human. Unfortunately, well controlled experiments in humans are difficult due to small patient populations, treatment medications which alter the seizure, and the ethical problems associated with invasive experimental procedures. Animal models of absence seizures provide a means of avoiding the above difficulties but the model should mimic, as closely as possible, the human condition. The goal of this thesis was to develop an animal model of absence epilepsy that could be used to explore, non-invasively, the underlying mechanisms of absence seizures. Functional magnetic resonance imaging (fMRI) was used to non-invasively monitor brain activity during absence seizures in various animal models. In this dissertation I report the development of a pharmacological rat model of absence seizures for use in fMRI investigations. Imaging was performed after absence seizure induction using γ-butyrolactone (GBL) and it was found that the cortico-thalamic circuitry, critical for the formation of SWDs, showed robust signal changes consistent with electroencephalographic recordings in the same animals. Since a major disadvantage of the GBL rat model is that it produces acute, drug-induced seizures, a genetic rat model with spontaneous absence seizures was subsequently developed for fMRI. EEG-triggered fMRI was used to identify areas of brain activation during spontaneous SWDs in the epileptic WAG/Rij rat strain under awake conditions. Significant signal changes were apparent in several areas of the cortex and several important nuclei of the thalamus. These results draw an anatomical correlation between areas in which there is increased fMRI signal and those where SWDs have been previously recorded using electrophysiologic techniques. One way in which absences differ between humans and both of these rat models is that the SWD frequency in humans is classically 3 Hz while in rats it varies from 7 to 11 Hz. Marmoset monkeys were found to model the human absence seizure condition better than other animals because GBL administration in these non-human primates results in the formation of 3 Hz SWDs. This monkey model was developed for awake functional imaging and changes in signal intensity in the thalamus and sensorimotor cortex correlated with the onset of 3 Hz SWDs. The change in BOLD signal intensity was bilateral but heterogeneous, affecting some brain areas more than others.

Descrevemos modelo original de sinovite experimental em coelhos imunizados com colágeno V com escasso processo inflamatório, intenso remodelamento matricial e vasculite. Analise morfológica e bioquímica foi realizada em coelhas Nova Zelândia (N=20) imunizadas com colágeno do tipo V, comparadas com controles. Foi observado o aumento dos colágenos I, III e V, oclusão do lúmen vascular e escasso processo inflamatório. A análise bioquímica confirmou a fibrose com aumento da síntese de colágeno. Nós postulamos que as alterações sinoviais descritas neste modelo foram conseqüência das particularidades do colágeno V, que promove manifestações imunológicas e clínicas semelhantes à esclerodermia / We described an original model of experimental synovitis in rabbits immunized with collagen V with scant cellular infiltration, intense matrix remodeling and vasculitis. Morphological and biochemical analysis were realized in New Zealand female rabbits (N=20) immunization with type V collagen, compared with control rabbits. It was observed increase of collagen I, III and V, vascular lumen occlusion and scant inflammatory process. Biochemical analysis confirmed the fibrosis with increased synthesis of collagen. We postulate that synovial changes described in this model are consequence of collagen V particularities, which promotes immunologic and clinical manifestations similar to scleroderma

Dorsal root ganglia (DRG) cell preparations are commonly used to study the properties of sensory neurons in relation to nociception. A typical DRG cell preparation contains both neurons and glial cells, and in addition to a conventional supportive role of glial cells, an increasing volume of literature has reported interactions between neurons and accompanying glial cells. A typical mixed DRG cell preparation can be separated into a neuron-enriched cell fraction and a preparation of purified glial cells. Using these purified cell fractions, we can study the relative contributions and interactions between neurons and glial cells in regulating neurite outgrowth and adenylyl cyclase-dependent cell signalling activity in vitro. / From our previous studies, pretreating DRG cell cultures with pertussis toxin (PTx) caused neurite retraction over a period of 2 h following the initial stimulus of removal from incubator. The purpose of the current study was to investigate whether this PIx-dependent response was specific to anyone of the three subpopulations of DRG neurons. Interestingly, no neurite retraction response was observed in enriched DRG cultures, including cultures enriched with isolectin B4 (IB4)-positive neurons or IB4-negative neurons. Addition of glial cells or conditioned medium from glial cells to IB4-negative cultures was necessary to restore the PTx-dependent neurite retraction response, which was then only observed in large diameter proprioceptive neurons. To conclude, glial cells constitutively release factor/s that stimulate neurite retraction in larger diameter neurons, and is counterbalanced by neuroprotective Gilo protein signalling pathway. / From our studies, we have provided evidence of bidirectional interactions between neurons and glial cells, with glial cells regulating neurite outgrowth and neurons regulating adenylyl cyclase activity in glial cells. These findings reveal the properties of glial cells in regulating neurite outgrowth and in producing prostanoid-stimulated responses. Moreover, our fmdings provide foundation to understand complex neuron-glia interactions in vivo which will eventually help to overcome obstacles in promoting neurite regeneration and in controlling pain. / In a parallel study, we proved that hyperalgesic agents such as prostaglandin E2 (PGE2) and the prostacyclin (PGI2) mimetic (cicaprost) stimulate cAMP production in DRG cell culture via EP4 and IP receptors, respectively. These prostanoids were presumed to act only on the neurons in typical mixed cell cultures, but since we had acquired purified glial cell preparation, we tested for involvement of glial cells in measurement of agonist-stimulated cAMP production. Interestingly, a purified glial cell cultures also produced EP4 and IP-dependent responses. The expression of EP4 and IP receptors by DRG glia was further confirmed by the detection of EP4 and IP-like immunoreactivity and mRNA. Moreover, these agonist-stimulated responses were greatest in the glial cell preparation, and surprisingly weakest in the neuron-enriched cell cultures. Furthermore, the presence of neurons significantly inhibited both EP4 and IP receptor-dependent signalling in glial cells, but was without effect on forskolin (agonist-independent) stimulation of adenylyl cyclase. In order to characterize this neuron-glia interaction, we tested the adenylyl cyclase activities in glial cell cultures which were treated with conditioned medium derived from neurons or were separated from physical contact with neurons plated on transwell membrane. These studies further suggest that the neuron-glia interactions were dependent on both soluble factors and cell-cell contact. / Ng, Kai Yu. / Adviser: Helen Wise. / Source: Dissertation Abstracts International, Volume: 73-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 152-172). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

In conclusion, the results suggested the important role of Ncl in driving the optic vesicle formation during early eye development. / The eye is a complex sense organ. It develops from different embryonic origins that including neural ectoderm, surface ectoderm, neural crest and paraxial mesoderm. Morphogenetic waves occur during eye development involve timely interactions of transcription factors and inductive signaling to ensure the correct temporal and spatial development of different components. Genetic studies of congenital eye defects, especially mutation screening and gene targeting, have provided the information about the molecular regulation in the complex processes of eye development. However, our knowledge of the basic genetic pathways that regulate the normal embryonic eye formation is incomplete. / Though the developing eye is believed to be highly specialized extension from the developing neural tube, the formation of major eye structure involves independent coordination of inductive interactions and regional specifications; formation of neural connections between retina and optic tectum; and maturation to a functional eye. There is not much information about eye-specific expression in early embryonic period. In this study, microarray was used to profile the molecular changes occurring in the developing mouse eye between the stage of optic vesicle evagination at E9.5 and completion of basic eye formation at P0. Differentially expressed transcription factor and signaling molecules, including nucleolin gene (Ncl), in the early developing eye were displayed. Temporal expression patterns were confirmed by quantitative real time PCR and spatial expressions patterns were confirmed by the whole-mount in situ hybridization. siRNA and overexpression vector targeting nucleolin transcript was designed to study their roles in the early eye morphogenesis during mouse embryogenesis in vitro. The loss of function phenotype after nucleolin knockdown was demonstrated by the absence of early optic vesicles with normal neural tube in the developing mouse embryos. Ectopic optic vesicle in developing mouse embryo was resulted under overexpression of Ncl . With the aim to study the biological roles of Ncl in mouse embryonic eye development in vivo, both conventional and conditional knockout techniques were attempted. The expression and functional studies revealed that a new neural tube independent signaling pathway regulated in the induction and formation of optic vesicles in the early eye formation. / Tang, Ling Yin. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3294. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 138-146). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Xie, Xinhui. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 163-193). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

by Yao Hong-Bing. / "January 2002." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (p. 113-135). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Descrevemos modelo original de sinovite experimental em coelhos imunizados com colágeno V com escasso processo inflamatório, intenso remodelamento matricial e vasculite. Analise morfológica e bioquímica foi realizada em coelhas Nova Zelândia (N=20) imunizadas com colágeno do tipo V, comparadas com controles. Foi observado o aumento dos colágenos I, III e V, oclusão do lúmen vascular e escasso processo inflamatório. A análise bioquímica confirmou a fibrose com aumento da síntese de colágeno. Nós postulamos que as alterações sinoviais descritas neste modelo foram conseqüência das particularidades do colágeno V, que promove manifestações imunológicas e clínicas semelhantes à esclerodermia / We described an original model of experimental synovitis in rabbits immunized with collagen V with scant cellular infiltration, intense matrix remodeling and vasculitis. Morphological and biochemical analysis were realized in New Zealand female rabbits (N=20) immunization with type V collagen, compared with control rabbits. It was observed increase of collagen I, III and V, vascular lumen occlusion and scant inflammatory process. Biochemical analysis confirmed the fibrosis with increased synthesis of collagen. We postulate that synovial changes described in this model are consequence of collagen V particularities, which promotes immunologic and clinical manifestations similar to scleroderma

Further in vivo functional studies were also performed. The SLC26A3 antibody was injected into the BALB/C mice seminiferous tubules using micropipette. The animals were sacrificed after three days, and CASA, daily sperm production (DSP) were used to evaluate sperm motility and spermatogenesis. The results showed that sperm motility was increased while there was no significant difference between DSP. Our results indicate that SLC26A3 on sperm does not play a dominant role in spermatogenesis, epididymal maturation and sperm motility. / In the first part of study, guinea pig sperm which were incubated in medium with various concentrations of Cl- resulted in varied percentages of capacitated sperm, in a concentration dependent manner. Depleting Cl-, even in the presence of HCO3 -, abolished sperm capacitation and vice versa, indicating the involvement of both anions in the process. Capacitation-associated HCO 3- dependent events, including cAMP production, protein tyrosine phosphorylation and pHi increase also depend on Cl - concentrations. Similar Cl- dependence was observed for sperm hyperactivated motility and sperm-egg fusion. The capacitation-associated events could also be significantly reduced by inhibitors or antibodies of CFTR and SLC26A3, with a more potent effect observed for niflumate, an inhibitor more selective for SLC26A3, over that of DIDS, an inhibitor more selective for SLC4 exchangers. The expression and localization of CFTR and SLC26A3 in guinea pig sperm were also demonstrated using immunostaining and Western blot analysis. Our results indicate that Cl- is required for the entry of HCO3- necessary for sperm capacitation, implicating the involvement of SLC26A3 in transporting HCO3 - with CFTR providing the recycling pathway for Cl- . / In the second part of study, GC-1 spg cell line that expresses SLC26A6 but not SLC26A3 was used as a negative control. The cells and sperm were pretreated with anion exchanger inhibitors and SLC26A3 antibody, and then membrane potential and intracellular calcium were measured. Our results showed that DIDS could inhibit the HCO3- deficiency induced depolarization of GC-1 spg cells as well as the depolarization induced by Cl- or HCO3- deficiency in sperm. Niflumate could inhibit the HCO3- induced [Ca 2+] i increase of the sperm but not GC-1 spg cells. SLC26A3 antibody had no effect on the GC-1 spg cells but it could block the depolarization caused by C--deficiency in sperm. / Our previous study has demonstrated the involvement of Cystic fibrosis transmembrane conductance regulator (CFTR) in transporting bicarbonate necessary for sperm capacitation. However, whether its involvement is direct or indirect remains unclear. The present study is design to investigate: (1) the possibility of a Cl-/HCO3- exchanger, solute carrier family 26, number 3 (SLC26A3), operating with CFTR during sperm capacitation, (2) the role and the underlying mechanisms of SLC26A3 in other sperm post-testicular processes and spermatogenesis. / Taken together, our results demonstrate the involvement of SLC26A3 in sperm function, particularly in transporting HCO3- necessary for sperm capacitation, which appears to be working with CFTR providing the recycling pathway for Cl- in parallel. The present results also provide an explanation to the observed subfertility in patients with SLC26A3 mutations. Further in vitro and in vivo studies also have shown that SLC26A3 does not play a predominant role in spermatogenesis but may affect other post-testicular maturation processes. / Chen, Wenying. / "November 2009." / Adviser: H.C. Chan. / Source: Dissertation Abstracts International, Volume: 72-01, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 101-109). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Kung, Wing Yee. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 92-115). / Abstracts in English and Chinese. / Abstract --- p.ii / Acknowledgements --- p.vii / Table of contents --- p.ix / List of Tables --- p.xii / List of Figures --- p.xiii / List of Abbreviations --- p.xv / Chapter Chapter 1. --- General introduction --- p.1 / Chapter Chapter 2. --- Literature review --- p.4 / Chapter 2.1 --- Food allergy and its prevalence --- p.4 / Chapter 2.2 --- Mechanism and clinical symptoms of food allergy --- p.6 / Chapter 2.3 --- Tropomyosin as the major allergen in shellfish --- p.15 / Chapter 2.4 --- Cross reactivity and epitope mapping of tropomyosin --- p.21 / Chapter 2.5 --- Novel approaches for the treatment of food allergy --- p.29 / Chapter Chapter 3. --- Expression of shrimp recombinant tropomyosin and sensitization of mice --- p.36 / Chapter 3.1 --- Introduction --- p.36 / Chapter 3.2 --- Materials and Methods --- p.40 / Chapter 3.2.1 --- "Recovery of E, coli with tropomyosin-carrying plasmid" --- p.40 / Chapter 3.2.2 --- Preparation of tropomyosin-carrying plasmid --- p.41 / Chapter 3.2.3 --- Confirmation of DNA sequence of the tropomyosin --- p.41 / Chapter 3.2.4 --- Identification of the recombinant protein --- p.43 / Chapter 3.2.5 --- Purification of the recombinant protein --- p.43 / Chapter 3.2.6 --- Sodium dedecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) --- p.44 / Chapter 3.2.7 --- Concentration measurement of the recombinant tropomyosin --- p.45 / Chapter 3.2.8 --- Mice --- p.46 / Chapter 3.2.9 --- Mice sensitization and challenging --- p.46 / Chapter 3.2.10 --- Tropomyosin-specific IgE level in blood --- p.47 / Chapter 3.2.11 --- Statistical analysis --- p.49 / Chapter 3.3 --- Results --- p.52 / Chapter 3.3.1 --- DNA sequence of the cloned tropomyosin --- p.52 / Chapter 3.3.2 --- Expression and purification of tropomyosin --- p.52 / Chapter 3.3.3 --- Hypersensitivity symptoms after challenge --- p.53 / Chapter 3.3.4 --- Blood tropomyosin-specific IgE level --- p.53 / Chapter 3.4 --- Discussion --- p.62 / Chapter Chapter 4. --- Identification of T cell epitopes --- p.67 / Chapter 4.1 --- Introduction --- p.67 / Chapter 4.2 --- Materials and methods --- p.67 / Chapter 4.2.1 --- Soluble epitope peptide synthesis --- p.68 / Chapter 4.2.2 --- Isolation of spleen cells from mice --- p.69 / Chapter 4.2.3 --- T cell proliferation assay --- p.70 / Chapter 4.3 --- Results --- p.71 / Chapter 4.3.1 --- Splenocyte proliferation to synthetic peptide --- p.72 / Chapter 4.3.2 --- Splenocyte proliferation to synthetic peptides pool --- p.72 / Chapter 4.4 --- Discussion --- p.77 / Chapter Chapter5 --- General conclusion --- p.89 / References --- p.92