VictorJuiz/thesis huggingface dataset:
Molecular cloning of three different Achlya ambisexualis hsp70 cDNAs, and changes in the accumulation of hsp70 transcript populations during hyphal branching

In the filamentous fungus 'Achlya ambisexualis' sexual differentiation is regulated by a set of steroid hormones. During vegetative growth, the hyphae of the organism appear smooth with occasional large branches. In response to the 'Achlya' steroid hormone antheridiol, numerous specialized lateral branches form that subsequently differentiate into gamete bearing structures. Hormone-induced branching is accompanied by changes in a number of transcript populations encoding different HSP70 heat shock proteins. Using both homologous and heterologous hsp70 probes, three different ' A. ambisexualis' hsp70 cDNAs were cloned and characterized. Analyses of the predicted amino acid sequences suggested that these cDNAs, encoded respectively: a cytoplasmic HSP70 protein, an endoplasmic reticulum HSP70 protein and a novel HSP70 protein; This latter HSP70 has a unique N-terminal extension that does not conform to known targetting motifs. The level of the hsp70 transcript population represented detected by this latter hsp70 cDNA was increased when cell cultures were depleted of glucose or treated with agents such as tunicamycin or calcium ionophore A23187. The above treatments have been reported to regulate hsp70 genes that encode proteins localized to the endoplasmic reticulum, or mitochondria. However, the HSP70 protein encoded by these transcripts has a unique N-terminal extension that does not conform to known organelle targetting signals and the ultimate cell location of this protein is not known as yet. The level of each of the three HSP70 transcript populations is altered during branching and differentiation by the hormone antheridiol. Similar changes in the levels of these populations were observed when hyphae underwent vegetative branching i.e. branching not related to sexual differentiation. These results suggest that common morphogenetic events take place during branching in both vegetative and sexually differentiating mycelia and that these events appear to require HSP70 chaperones.
Evolution of extended satellites in massive halos

The evolution of extended satellites in massive halos is studied in the weak and the strong regimes of satellite deformation. In the first part of the thesis we follow the dynamics of a spherical region evolving locally as an Einstein-de Sitter universe (<math> <f> <rm>q<inf>o</inf>=0.5,<g>W</g>=1</rm></f> </math>) and containing overdensities acting as seeds for the formation of a satellite and its future host. We study the dynamics of forming satellites when their hosts are still unvirialized, accreting material, and generating time-varying gravitational potentials (TVGP). The three main dynamical processes affecting the satellite are dynamical friction, the TVGP, and tidal disruption. The internal flow of energy inside a satellite and across its boundary is analyzed with specialized local and global methods, providing information on the nature, the magnitude and the timing of the individual processes. A strongly deformed satellite able to survive a few galaxy crossings forms a compact core from which dynamical friction extracts energy, while its halo is tidally disrupted by the "slingshot" effect. This leads to the formation of systems of external stellar shells and internal energy shells. Their origins and appearances are closely related. Satellite self-gravity and phase wrapping control the emergence of both types of shells from the satellite inner regions once non-linear effects set in. In the second part of the thesis, we analyze the combined effects of dynamical friction, tidal stripping, and 'internal' and 'external' two-body heating on satellites moving inside massive hosts. External two-body heating is a stochastic process that occurs inside a satellite as a back reaction to the scattering of inhomogeneous material in the surrounding stellar system. This type of heating accelerates the evolution of less bound objects by increasing their rate of evaporation. The heating becomes important at low satellite velocities, and when the masses of the perturbing objects are comparable to or greater than the masses of the satellites. We determine how the interplay of dynamical friction, tidal stripping, and internal and external two-body heating drives the evolution of satellite populations and we apply these results to satellites inside dwarf galaxies.
Preparation of human serum albumin microaggregates labelled with §9§9[superscript]m to examine the nasal deposition and clearance of suspended pharmaceutical formulations

In order to simulate the intranasal drug distribution of budesonide suspension aerosol, a tracer particle having a size distribution similar to this parent pharmaceutical was developed. This particle can be easily labelled with the $\gamma$-emitting radionuclide technetium-99m, and permits the study of deposition and subsequent movement of the formulation. Microaggregated human serum albumin (HSA) particles of about 2-3 microns in size were prepared by denaturing human serum albumin with a stabilizer and surfactant in a boiling water bath. By carefully controlling the time of thermal denaturation, microaggregates with the desired particle size distribution were prepared. Microaggregates were labelled with Tc-99m by adding diluted stannous chloride to reduce the $\rm\sp{99m}$Tc(VII) to $\rm\sp{99m}$Tc(V) and subsequently bind the $\rm\sp{99m}$Tc to the albumin. Polycarbonate membrane filters (Nuclepore) were utilized to perform particle size analysis by differential filtration. In addition, a quantitative, non-invasive three-dimensional image of human serum albumin microaggregates was obtained by using the laser confocal scanning microscope (Bio-Rad 600). The aerodynamic size distribution of microaggregates suspended in distilled water were verified by a single-particle, laser sizing system based on the time-of-flight data. Fifty percent of dried, aerosolized microaggregate particles were determined to be smaller than 2.040 microns in aerodynamic size, compared to 2.099 microns of the parent pharmaceutical. The characteristics of the tracer particles in an aqueous vehicle after nebulization was studied with an Andersen Impactor. Using a versatile shear cell, the diffusion coefficients of $\rm\sp{99m}$Tc microaggregates and of the parent pharmaceuticals in a viscous vehicle were compared.
Analysis of presynaptic metabotropic glutamate and adenosine A¦1 receptors

As an initial step towards understanding the mechanism of receptor-mediated suppression of synaptic transmission, I attempted to characterize the G-protein coupling properties of the adenosne A1 receptor and the metabotropic glutamate receptor, mGluR4a, using the baculovirus-Sf9 insect cell expression system. The ability of each receptor to discriminate amongst co-expressed G-protein subunits was explored. Furthermore, a solubilization procedure was established to study the native coupling of metabotropic glutamate receptors and G-proteins in rat brain tissue. Results from radioligand binding experiments demonstrated an increase in agonist affinity, as well as a gain of GTP-sensitivity, when A1 receptors were co-expressed with [alpha]2 and [alpha]3 but not [alpha]s or [alpha]o in Sf9 cells. No significant increase in affinity for the agonist (3H) -L-AP4 was observed when mGluR4a was co-expressed with [alpha]1, [alpha]2, [alpha]3, [alpha]s or [alpha]o. Hence, the results from this study indicate that under the current conditions adenosine A1 receptors, but not mGluR4a, undergo selective coupling to members of the Gi family of G-proteins.
Teacher, student, and parent perceptions of reporting practices in mathematics, a study at the grade 8 level

This study examined teacher, student and parent perceptions of reporting practices in mathematics. The participants for this study included eight Grade 8 teachers, three students from each class for a total of 24 students, and a parent of each student for a total of 24 parents. Teachers were selected from names suggested by the Assistant Superintendent of the Regina Public School District. Students were then selected by their teachers and included students who were doing well in mathematics, students who were achieving satisfactorily and students who were experiencing difficulty in mathematics. In this way, a range from the classroom was represented. This study was conducted using an interview technique, and took place in the spring of 1995, following the second reporting period of that school year. The teachers, students and parents were interviewed in regard three major areas, all with respect to mathematics: (1) The communication that exists among teachers, students, and parents with regard to grading criteria and meanings of reports; (2) Teachers', students', and parents, cognitive understanding about grades, report cards and reporting practices; and (3) Teachers', students', and parents' attitudes and feelings about reporting practices including their opinions about the consequences of reporting. Student interview responses were compared to the interview responses of their respective parent and teacher. Comparative analysis was then used to develop case descriptions. Also, emerging categories and themes were determined through coding of the data. The majority of participants in this study were satisfied with the reporting practices used for Grade 8 mathematics. Most were very comfortable with letter grades and thought they understood them. There was some definite confusion regarding standardization of letter grades. Even though most participants recognized that letter grades in one class did not necessarily mean the same as in another class, this did not appear to be an issue. The confidence that the students and parents had in the teacher was an overriding factor.
Identification and characterization of a homophilic binding and neuritogenic site in the cell adhesion molecule L1

The neural cell adhesion molecule L1 is an integral membrane glycoprotein which mediates cell-cell adhesion and promotes neurite outgrowth from neuronal cells. Mutations in the L1 gene have been implicated in several neurological diseases. To investigate the mechanism and the relationship of these two intrinsic functions of L1, studies were carried out to identify specific domain(s) and sequences involved in homophilic binding and the promotion of neurite outgrowth. Recombinant L1 domain proteins were used to identify the domain involved in L1 homophilic binding. Results based on Covasphere binding assays indicate that the second Ig-like (Ig2) domain of L1 is sufficient and necessary for homophilic interaction. Results from neurite outgrowth assays further demonstrate that the Ig2 domain of L1 is a potent neuritogenic substrate. The colocalization of these two intrinsic activities of L1 suggests a close relationship between homophilic binding and the promotion of neurite outgrowth. Several HSAS/MASA (Hydrocephalus as a result of stenosis of the aqueduct of Sylvius/mental retardation, aphasia, shuffling gait and adducted thumbs) mutations have been localized to L1 Ig2. The effects of two HSAS/MASA mutations on the homophilic binding and neuritogenic activities of recombinant L1 Ig2 were assessed. The HSAS mutation R184Q abolished both Ig2-associated activities, while the MASA mutation H210Q had only modest effects. The deleterious effects of these two mutations thus correlate very well with the severity of their respective clinical phenotype. The results also implicate a role for Arg-184 in L1 homophilic binding The synthetic oligopeptide approach was used to identify the homophilic binding site in L1 Ig2. The peptide containing sequences flanking Arg-184 (HIKQDERVTMGQNG) inhibited both L1-dependent cell aggregation and neurite outgrowth, whereas the peptide consisting of flanking sequences of His-210 had only minor effects. Further analysis using peptide analogues indicates that the charged residues as well as the hydrophobic residues immediately adjacent to Arg-184 may also play an important role in L1 homophilic binding. Peptides that inhibited L1 homophilic binding also inhibited L1-dependent neurite outgrowth, suggesting a direct link between these two intrinsic activities of L1.
Antioxidant therapy for the management and prevention of adult respiratory distress syndrome

The development of the Adult Respiratory Distress Syndrome (ARDS) in the critically ill patient is associated with a significant morbidity and mortality. The pulmonary dysfunction in ARDS is largely secondary to neutrophil-mediated oxidant injury. The purpose of these studies was to examine the effect of the antioxidant N-acetyl cysteine (NAC) on a rodent model of lung injury. We postulated that NAC might attenuate lung injury following intratracheal challenge with endotoxin (LPS). Male Sprague-Dawley rats were administered NAC systemically either before or after intratracheal administration of LPS. Lung injury was assessed by measuring the transpulmonary leakage of $\sp{125}$I-albumin, pulmonary myeloperoxidase (MPO) content, bronchoalveolar lavage (BAL) fluid cell counts, pulmonary lipid peroxidation and histology. NAC administration significantly attenuated the LPS-induced increases in lung albumin leakage (LPS: 0.24 $\pm$ 0.08 vs LPS + NAC: 0.12 $\pm$ 0.03, p $<$ 0.05) and reduced the LPS-dependent increase in lipid peroxidation. However, total and differential BAL cell counts and MPO content were not affected by NAC pretreatment. Although neutrophil influx was unaffected, neutrophil activation as assessed by surface CD11b expression and chemiluminescence was significantly downregulated by NAC. Importantly, NAC administration up to two hours after endotoxin challenge was still able to significantly ameliorate LPS-induced lung injury. Our data suggests that the attenuation of acute lung injury by NAC in our rodent model is related to free radical scavenging and inhibition of the neutrophil oxidative burst, rather than by an effect on inflammatory cell migration. These results suggest novel approaches for therapeutic interventions in acute lung injury.
The role of vascular wall mechanics in the failure of surgical bypass grafts

The long term patency of surgical bypass grafts is reduced by the development of distal anastomotic intimal hyperplasia (DAIH), which can lead to stenosis or thrombosis of the graft-artery junction. The non-physiological structural mechanics of the vascular reconstruction are thought to promote DAIH, however, the exact mechanism of DAIH formation has not yet been elucidated, and is the subject of this thesis. Even though arterial behaviour is nonlinear and anisotropic, and arteries are subject to large strains and deformations 'in vivo', most analyses of vascular mechanics in complex three dimensional geometries use linear, isotropic, small strain models. In the present study, a strain energy density function (SEDF) <math> <f> <g>r</g><inf>0</inf>W=<fr><nu>1</nu><de>2</de></fr>a<b>I<sup> <rm>2</rm></sup><inf><it>E</it></inf>-<it>b<b>II<inf><it>E</it> </inf></b></it></b></f> </math> is used to describe the large strain mechanics of blood vessels. This model is shown to predict the nonlinear stress stiffening behaviour of blood vessels as well as the role of residual stresses in reducing stress gradients through the vessel wall. The applicability of this model to describing the behaviour of blood vessels subjected to physiological axial stretches, inflation pressures and torsion is also demonstrated. The above SEDF is incorporated into an efficient finite element model of vascular mechanics so that the stress distribution in complex 3-D graft-artery anastomoses can be calculated. Stress analyses of graft-artery junctions, which include suture-induced stress concentrations, are presented. These analyses demonstrate that, in the first few months following implantation, large stress concentrations exist around the suture-line. Histological examination of coronary artery bypass grafts (CABG) shows that during this time, DAIH develops mostly around the suture-line. Together, these findings suggest that early hyperplasia development in CABGs is promoted by high suture-induced stresses. A further analysis of the influence of graft-artery compliance mismatch on suture-induced stresses demonstrates that increased compliance mismatch at end-to-end anastomoses ' does not' increase anastomotic stress concentrations, however, in end-to-side anastomoses, it 'does' lead to a substantial increase in anastomotic stresses. This combination of results explains previous experimental findings that increased compliance mismatch 'does not' lead to increased DAIH in end-to-end anastomoses, but in end-to-side anastomoses, it 'does' lead to a profound increase in DAIH. Finally, since high suture-line stresses are found in both end-to-end and end-to-side junctions, elevated intramural stresses may be an important proliferative stimulus for DAIH in all vascular reconstructions.
There must be no drawing back, the Catholic Church's efforts on behalf of non-English-speaking immigrants in Toronto, 1889-1939

This study of Catholic episcopal policy and action towards non-English speaking Catholic immigrants in Toronto during the period 1889-1939 encompasses the administrations of five Archbishops, their personal endeavours to serve a growing Catholic population, and the Catholic institutions that served the Archdiocese of Toronto. Three initiatives served as benchmarks in the local Church's immigrant aid endeavours: Archbishop Neil McNeil's personal efforts to assist Catholic immigrants to Canada; "women's work" for the Church as reflected in the establishment of the Catholic Women's League of Canada and the founding of the Sisters of Service, a new Canadian religious order; and the establishment of Friendship House and Catholic Settlement House under the auspices of lay and religious initiatives. Inspired by religious duty, fear of proselytizing efforts, and a growing sense of Canadian nationalism and civic duty, the Church met the challenge first with cautious support, then later with energetic social action programmes.
Axon guidance along the dorsoventral axis of Caenorhabditis elegans

Axon guidance along the dorsoventral axes of animals belonging to diverse phyla involves secreted netrin/UNC-6 laminin related guidance cues and the UNC-5 and DCC/UNC-40 receptor families. Genetic studies in 'C. elegans ' reveal that both UNC-5 and UNC-40 are required to repel motile cells or axons away from UNC-6, while UNC-40 is required to attract motile cells or axons toward ventral sources of UNC-6. The UNC-5 guidance receptor, in response to the UNC-6/netrin path cue, orients growing axons in a dorsal direction along the epidermis of ' C. elegans'. When ectopically expressed in the touch receptor neurons, which normally extend ventrally or longitudinally, UNC-5 is able to reorient their axons toward the dorsal side in an UNC-6 dependent manner. This property forms the basis of a genetic screen to identify other mutations that, like ' unc-6' mutations, suppress 'unc-5'-induced growth cone guidance. These mutations may identify new components required for pioneer axon guidance by 'unc-5'. In this study, I describe eight genes that are required for ectopic 'unc-5'-induced growth cone steering. Four are the previously known axon guidance genes 'unc-6, unc-40, unc-34 ', and 'unc-44', and four are the novel genes: ' unc-129, seu-1, seu-2', and 'seu-3'. I propose that some or all of these genes may function in a developmentally important ' unc-5' signaling pathway. Mutations in 'unc-129' cause dorsal axon guidance defects that are similar to those exhibited by mutations in 'unc-5, unc-6', and 'unc-40'. I show that 'unc-129' encodes a novel member of the transforming growth factor-ß (TGF-ß) family of secreted signaling molecules and is expressed in a restricted pattern that includes motor neurons and dorsal body wall muscle. By further restricting expression to either motor neurons or to muscle, I found that expression in muscle is required for axon guidance. Ectopic expression studies indicate that asymmetric expression of 'unc-129', with expression in dorsal, but not ventral body wall muscle, is essential for axon guidance. The work discussed here provides the first functional evidence that a TGF-ß is involved in a phylogenetically conserved axon guidance mechanism.
Functional analysis of the homeobox gene Tlx-2 during mouse embryogenesis

This thesis describes the cloning of the 'Tlx-2' homeobox gene, the determination of its developmental expression, the characterization of its function in mouse mesoderm and peripheral nervous system (PNS) development, the regulation of 'Tlx-2' expression in the early mouse embryo by BMP signalling, and the modulation of the function of TLX-2 protein by the 14-3-3 signalling protein during neural development. 'Tlx-2' is a murine homeobox gene related to the human T-cell leukemia oncogene 'HOX11'. During early mouse development, ' Tlx-2' is expressed in the ectoderm, and the primitive streak. ' In vivo' and 'in vitro' experiments demonstrate that BMP2/4 signalling activates the expression of 'Tlx-2', suggesting that during mouse embryogenesis 'Tlx-2' is a downstream target gene in a BMP signalling pathway. A targeted mutation of 'Tlx-2' leads to early embryonic lethality, and the homozygous embryos display severe defects in the primitive streak and in mesoderm formation. The phenotype of ' Tlx-2' mutant embryos demonstrate an essential role of 'Tlx-2 ' in mouse mesoderm formation, a developmental process regulated by BMP 2/4 signalling. These findings suggest a BMP/Tlx-2 signalling pathway required for mammalian mesoderm development. 'Tlx-2' is specifically expressed in the developing PNS after E9.0, including the sensory and autonomic ganglia derived from the neural crest. A role for 'Tlx-2' in PNS development is suggested by the coincidence of the evolution of the 'Tlx-2' expression pattern and the ontogenesis of the PNS. Overexpression of 'Tlx-2' in PC 12 cells suppresses neurite outgrowth induced by NGF, indicating that ' Tlx-2' is a negative regulator of neural differentiation. Furthermore, TLX-2 is a transcription repressor as demonstrated by co-transfection assays. These results suggest that 'Tlx-2' suppresses neuronal differentiation during the early phase of gangliogenesis, probably by its repression of neuronal gene expression. TLX-2 is associated with the 14-3-3 [eta] protein both 'in vitro ' and 'in vivo'. The physiological significance of the physical interaction of TLX-2 and 14-3-3 [eta] is demonstrated at several levels: 'Tlx-2' and '14-3-3' [eta] are co-expressed in the developing PNS and in PC12 cells, 14-3-3 [eta] enhances the nuclear localization of TLX-2, and 14-3-3 [eta] and TLX-2 cooperatively suppress neurite outgrowth of PC 12 cells. These results indicate that the function of the TLX-2 homeodomain is probably regulated by cell signalling mediated by 14-3-3 proteins. This work contributes to an understanding of the function the ' Tlx-2' homeobox gene and of the regulation of the 'Tlx-2' function during mouse embryogenesis, and provides novel insights into the molecular control of mouse mesoderm and PNS development.