A 2 x 2 factorially designed experiment was conducted to study the effects of feeding two levels of calcium and phosphorus alone and in combination, on magnesium utilization in ruminants. Twelve wether lambs were used in two metabolism trials. The two levels of calcium were 0.4 and 1.4% and the two levels of phosphorus were 0.3 and 1.3%. Apparent magnesium absorption, expressed as percent of intake was lower for the high-calcium fed lambs (P< .05) and for the high-phosphorus fed lambs (P< .01). Urinary magnesium excretion was lower (P< .01) for the high-phosphorus fed lambs. Urinary calcium excretion was lower (P< .01) for the high-phosphorus fed lambs. Calcium retention was higher (P< .01) for the high-calcium fed lambs. Apparent phosphorus absorption, phosphorus retention and urinary phosphorus excretion were higher (P< .01) for the lambs fed the high-phosphorus level. Serum magnesium was lower (P< .01) and serum inorganic phosphorus was higher (P< .01) for the high-phosphorus fed lambs. Serum calcium was higher (P< .05) for the high-calcium fed lambs and lower (P< .01) for the lambs receiving the high-phosphorus rations. Apparent digestibility of ether extract, and dry matter content of the feces were higher (P< .05) for the lambs fed the high-calcium level and lower for the high-phosphorus fed lambs (P< .01). The significant (P< .01) interaction between calcium and phosphorus levels on dry matter of feces indicates that high dietary calcium was partially effective in reversing the detrimental effects of high-phosphorus level. / Master of Science

This thesis attempts to demonstrate the harmony between technique and meaning in the work of James Purdy, a contemporary American short story writer and novelist. Four major themes are explored and examined in depth: the universal human need for love and recognition; the desire to escape the past and achieve rebirth; the failure of the family unit to promote the growth of its children; and the dream-like perception of internal human reality. Purdy's use of dialogue, imagery, characterization, grotesque scenes, and written versions serves to complement the analysis of the themes. Among the works discussed are five novels and a novella: Malcolm, The Nephew, Cabot Wright Begins, Eustace Chisholm and the Works, Jeremy's Version, and "63: Dream Palace." Some attention is given to selected short stories in Color of Darkness and Children Is All. In addition, Purdy's importance as a significant voice in American fiction is given consideration. / Master of Arts

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Hoodia gordonii à uma planta da famÃlia das apocinÃceas. OriginÃria do sudeste da Ãfrica, onde tem sido historicamente usada para suprimir o apetite durante longas jornadas de caÃa, sendo utilizada em diversos paÃses com o objetivo de emagrecer. No Brasil foi retirada do mercado devido à falta de estudos que comprovem sua eficÃcia e seguranÃa para o uso. O objetivo deste trabalho foi avaliar as alteraÃÃes comportamentais, neuroquÃmicas e glicolipÃdicas em ratos tratados com Hoodia gordonii. Para a realizaÃÃo deste estudo H. gordonii foi administrada por via oral nas doses de 25 e 50 mg/Kg durante oito dias consecutivos em ratos Wistar machos (160-200g), D-anfetamina 2 mg/Kg foi administrada intraperitonealmente de forma aguda e usada como padrÃo positivo. Os testes aconteceram 60 minutos apÃs o ultimo dia de tratamento com a Hoodia e 30 minutos apÃs o tratamento com D-anfetamina. Foram avaliados a variaÃÃo de peso dos animais durante o tratamento, bem como o consumo de Ãgua e comida. Para os testes comportamentais foram feitos os testes de labirinto em cruz elevado, campo aberto e placa perfurada. Para os estudos neuroquÃmicos foi feito HPLC com detecÃÃo eletroquÃmica. Para os testes glicolipÃdicos foi feita dosagem de Glicose, HDL, LDL, TG, colesterol total, ALT e AST. Os resultados mostraram que H. gordonii à capaz de reduzir o ganho de massa corpÃrea, bem como reduzir o consumo de comida e Ãgua. Os resultados dos testes comportamentais mostraram que ela à capaz de reduzir os parÃmetros observados no teste do labirinto em cruz e placa perfurada sem mostrar alteraÃÃo significante no campo aberto. Os resultados dos experimentos neuroquÃmicos evidenciaram um aumento do conteÃdo de noradrenalina e dopamina em corpo estriado de ratos, detectados eletroquimicamente pelo HPLC. Nos testes bioquÃmicos foi visto que ela tem a capacidade de reduzir os nÃveis de glicose, bem como a concentraÃÃo de triglicerÃdeos e colesterol total em soro de ratos, sem mostrar alteraÃÃo significante da ALT e AST. Foi possÃvel concluir que H. gordonii à capaz de reduzir a ingestÃo de alimentos e que este efeito pode estar de alguma forma ligado à neurotransmissÃo noradrenÃrgica e dopaminÃrgica, possuindo tambÃm atividade ansiogÃnica evidenciada pelos estudos comportamentais. / Hoodia gordonii is a plant of the family apocinaceae. Originally from southeastern Africa, where it has historically been used to suppress appetite during long hunting trips, being used in several countries in order to lose weight. In Brazil was withdrawn from the market due to lack of studies proving its efficacy and safety for use. The aim of this study was to evaluate the behavioral changes and neurochemical glicolipÃdicas in rats treated with Hoodia gordonii. For this study H. gordonii was administered orally at doses of 25 and 50 mg/kg for eight consecutive days in male Wistar rats (160-200g), D-amphetamine 2 mg/kg was intraperitoneally administered acutely and used as a positive standard. The tests took place 60 minutes after the last day of treatment with the Hoodia and 30 minutes after treatment with D-amphetamine. We evaluated the weight change of the animals during treatment, as well as the consumption of water and food. For behavioral tests were performed tests elevated plus-maze, open field and hole board. For neurochemical studies was done HPLC with electrochemical detection. For testing was done glycolipid glucose, HDL, LDL and TG, total cholesterol, ALT and AST. The results showed that H. gordonii is capable of reducing body mass gain and reduce the consumption of food and water. The results of behavioral tests showed that it is able to reduce the parameters observed in the plus-maze test and hole board showing no significant change in the open field. The results of experiments showed an increase in the neurochemical content of noradrenaline and dopamine in the striatum of rats electrochemically detected by HPLC. In biochemical tests it was seen that it has the ability to lower blood glucose levels as well as the concentration of triglycerides and total cholesterol in serum from mice, showing no significant change in ALT and AST. It was concluded that H. gordonii is able to reduce food intake, and this effect may be somehow linked to the dopaminergic and noradrenergic neurotransmission, having also anxiogenic activity evidenced by behavioral studies.

Ce travail de thèse a porté sur l'étude de l'équilibre entre la prolifération et la différenciation dans le cadre de la myogenèse embryonaire et postnatale. Chez l'embryon, le sortie du cycle cellulaire est contrôlé par p57 et p21 pendant la myogenèse. Nous avons montré que la voie de signalisation Notch ainsi que les facteurs de régulation myogéniques (MRFs) régulent l'expression de p57 dans les cellules progénitrices et les myoblastes en différentiation. Chez l'adulte, p21 et p57 ne sont pas exriés dans la population quiescente de cellules souches du muscle (cellules satellites - SCs). p21 et p57 sont rapidement induits après activation et durant la différentiation des SCs. Ex vivo, les myoblastes déficients pour le gène p21 présentent des défauts de prolifération et de différenciation. In vivo, l'étude de la régénération musculaire chez les mutants p21 a montré une réduction précoce des SCs, avec un retard de reconstitution du tissu musculaire. Afin de pouvoir étudier le rôle de p57 après la naissance (les mutants p57 meurent à la naissance) nous avons généré un modèle murin permettant de muter le gène p57 de manière spatio-temporelle avec le système de recombinaison Cre/LoxP. Nous avons combiner notre allèle p57 conditionnel avec une Cre exprimée de manière ubiquitaire, et observé des phénotypes identiques aux phénotypes décrits précédemment chez les souris présentant une perte du p57. L'ablation conditionnelle de p57 dans les SCs adultes, a conduit à une diminution de la différenciation myogénique in vitro. Notre travail suggère que p21 et p57 jouent un rôle important dans la régulation de la différenciation et le cycle cellulaire dans le muscle adulte. / This thesis focuses on the coordination of proliferation and differentiation in embryonic and adult myogenesis. During development, we demonstrated that skeletal muscle progenitors interact with the differentiating myoblasts via the Notch pathway to maintain their pool. It has previously been established that p57 and p21 redundantly promote cell cycle exit in developing muscle and we showed that Notch and Myogenic Regulatory Factors act through muscle-specific regulation of p57. We then examined p21 and p57 in adult skeletal muscle stem cells, called satellite cells (SCs). Although absent from quiescent SCs, p21 and p57 are expressed upon activation (including proliferating myoblasts) and differentiation. p21-null myoblasts exhibited proliferation and differentiation defects in myofiber cultures, implicating p21 at the early activation phase. In vivo muscle regeneration studies with p21 mutants showed an early impact on the SC pool, while SCs and muscle structure were re-established by the end of regeneration. Since p57-deficient mice die at birth, we generated a conditional knock-out (KO) allele for postnatal studies using the loxP/Cre recombination system. With a ubiquitous Cre we observed developmental and perinatal phenotypes similar to previously described KO embryos. The new p57 allele also includes a β-galactosidase reporter and we showed that it recapitulates p57 expression profile in embryonic and adult tissues. Conditional ablation of p57 in adult SCs reduced myogenic differentiation in primary myoblast culture. Our work suggests that p21 and p57 are involved in adult myogenesis and cell cycle exit, working at the early steps of satellite cell activation.

Maintenance of the hematopoietic system is dependent upon the proper regulation and orchestrated functions of the hematopoietic stem cell (HSC) pool. A number of extrinsic signaling pathways and intrinsic regulators have been found to regulate HSC processes. However a full understanding of the ability of HSC to balance the processes of self-renewal, quiescence, and lineage specification is not yet clear. We therefore set out to identify novel HSC regulators by comparative gene expression analysis of whole genome transcriptomes generated for long-term (LT)-HSC (Hoechst low/- Lin- Sca1+ cKit+ CD34-), short-term (ST)-HSC (Hoechst low/- Lin- Sca1+ cKit+ CD34+), and non-HSC (Hoechst+) of the bone marrow. These studies identified IGF2 as one of the most differentially expressed genes within LT-HSC, suggesting a potential role for IGF2 in the regulation of HSC. Using a combination of lentiviral-mediated overexpression and knockdown experiments, we found IGF2 to confer enhanced self-renewal in vitro and in vivo. Overexpression of IGF2 resulted in an increased percentage of multi-lineage colonies within colony-forming unit (CFU) assays without affecting lineage specification. In vivo, serial bone marrow transplantation revealed that IGF2 within HSC enhances short-term and long-term donor contribution. Analysis of the expression of key cell cycle regulators revealed that IGF2 induced upregulation of p57 expression specifically within HSC. This upregulation could be attributed to differences in the methylation status of the p57 promoter in HSC compared to other progenitor and mature blood cell populations. p57, a member of the Cip/Kip family of cyclin dependent kinase inhibitors, has recently been shown to be required for the regulation of HSC quiescence and long-term self-renewal. Analysis of bone marrow obtained from primary and secondary transplant recipients showed that overexpression of IGF2 resulted in an increased percentage of quiescent HSC. Treatment of HSC overexpressing IGF2 with LY294002, a PI3K-Akt inhibitor, prevented IGF2-mediated upregulation of p57 expression. These findings demonstrate that within HSC, IGF2 induces p57 expression through activation of the PI3K-Akt pathway to regulate HSC quiescence. We have identified a novel role for IGF2 in HSC function, providing new insights into the biology of HSC and opening potential platforms for the development of better therapies involving HSC-mediated hematopoietic reconstitution.

This study was an investigation of the perceptions of 65 remarried couples of the issues and tasks set forth in current literature on remarriage that are said to be experienced in common by the remarried family as it integrates into an on-going, stable, supportive unit. Analysis of the survey instrument results indicated that all of the items were perceived as having been experienced in the past by at least 17% of the sample, with often considerable spread between the number experiencing an item and the number experiencing disturbance because of the item. There was strong evidence that the partners perceived a lessening over time in the degree of disturbance experienced in their remarriage and that certain aspects of remarriage family integration processes were more or less troublesome according to the role the individual partner played in the remarriage. Implications for family education and counseling are offered. / M.S.

Dans le cadre de la recherche de composés pouvant stimuler la sécrétion de l’hormone hypoglycémiante GLP-1 (glucagon-like-peptide 1) et sur des critères ethno-pharmacologiques et taxonomiques, différentes Asclepiadoidées ont été criblées sur un modèle cellulaire (lignée STC-1). Cette approche nous a permis de sélectionner deux espèces de Cynanchum malgaches. L’isolement bio-guidé de C. marnierianum a conduit à la purification de 2 nouveaux glycosides prégnaniques, les marnieranosides. L’exploration phytochimique de C. menarandrense a permis l’identification de 5 nouvelles structures prégnaniques et de 2 prégnanes déjà signalés dans un genre taxonomiquement proche et hypoglycémiant : Caralluma. Les prégnanes purifiés ont aussi été évalués pour leur effet sécrétagogue GLP-1 et cytotoxique mais seuls les marnieranosides se sont avérés bioactifs. Des analogies structurales entre les molécules identifiées dans le genre Cynanchum et des molécules bioactives isolées au préalable d’espèces antidiabétiques (genres Hoodia et Caralluma) valident notre stratégie pour la découverte des métabolites secondaires avec un potentiel antidiabétique. / In the framework of our search for antidiabetic compounds capable of stimulating the secretion of the hypoglycemic hormone GLP-1 (glucagon-like-peptide 1), based on ethnopharmacological and taxomic criteria, several Asclepiadoidae plants were screened with an in vitro model (STC-1 cell line). This approach led to the selection of two Malagasy Cynanchum species.Bio-guided fractionation of C. marnierianum led to the purification of two new pregnane glycosides named marnieranosides. The phytochemical study of C. menarandrense led to the identification of 5 new pregnane structures along with 2 pregnanes previously reported in the closely related and hypoglycemic Caralluma genus. The isolated pregnanes were evaluated for their GLP-1 secretagogue and cytotoxic activity but only the marnieranosides were proven bioactive. Structural similarities of the Cynanchum pregnanes with the ones previously isolated from antidiabetic plants (Hoodia and Caralluma), validated our approach for the discovery of secondary metabolites with antidiabetic potential.

Ruthenium-based homogenous catalysis is a broad and extremely useful branch of transition metal catalysis. Surely, the most famous example is olefin metathesis, for which Yves Chauvin, Robert Grubbs and Richard Schrock were awarded the 2005 Chemistry Nobel Prize. Although some of the most well-known catalysts are widely used and considered benchmark catalysts, the research around this topic has not stopped. The modification of known systems to achieve better performance and better understanding of the catalytic mechanism is very important and an example of such modification is reported in this thesis. The newly synthesised catalysts were compared to the parent commercially available catalyst showing better reactivity. Ruthenium catalysis, though, is not limited to olefin metathesis and C-H activation, for example, it has become a useful approach to the functionalisation of organic molecules. In this field, the deuteration of C-H bonds is an interesting transformation, which has many applications. The synthesis of new hydridosilylruthenium complexes and their application in the deuteration of a variety of substrates is reported in this manuscript. The unprecedented synthesis of tetradeuterated Ketoprofene is also reported. Recently, ruthenium-based catalysts have found application in the dehydrogenation of suitable compounds, such as formic acid, ammonia-borane and other hydrogen-rich substances. The driving force behind these discoveries is the use of H2 as an energy vector in place of fossil fuels. A hydrido-ruthenium catalyst was shown to catalyse the decomposition of formic acid in CO2 and H2 and to catalyse the reduction of olefinic substrates. The released CO2 from the reaction did not interfere with the fuel cell due to its inertness. This property makes its employment as C1 source very challenging, although its use would also be extremely attractive because of the abundance of this gas. In these regards, both frustrated Lewis pairs (FLPs) and gold catalysts have shown interesting reactivity in the activation of CO2. A new FLP and a silica supported gold catalyst were synthesised to test them in CO2 activation and the results are reported in this manuscript.