Dissertations / Theses on the topic 'Endō'

Projeto de Pós-Graduação/Dissertação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Medicina Dentária
Introdução: Este trabalho teve como objetivo a realização de uma revisão de literatura sobre a doença endo-perio. Nesta medida, foram exploradas as relações biológicas entre a polpa e o periodonto, nomeadamente as vias de comunicação existentes, os fatores que contribuem para o seu aparecimento, persistência e/ou agravamento, tendo sido sublinhados os factores etiológicos e a influência da patologia pulpar no periodonto e viceversa. Foram, também, referidas as principais classificações das lesões endo-perio e a problemática do diagnóstico, tratamento e prognóstico dos dentes envolvidos. Materiais e métodos: Esta revisão foi realizada com o limite temporal de 1975 a 2014, recorrendo ao motor de busca Google e às bases de dados Medline/ PubMed, B-on, Science direct, utilizando as seguintes palavras-chave: endo-perio lesions, classification of endo-perio lesion, microbiology, pathways of communication, diagnosis in endoperio lesions, treatment of endo-perio lesions. Após a leitura dos resumos, a seleção dos artigos foi efectuada de acordo com a especificidade do tema e com os limites temporais acima referidos. Foram, ainda, consultados livros na área de Endodontia na biblioteca da FCS-UFP. Os critérios de exclusão dos artigos foram os artigos pagos e aos quais não se obteve resposta por parte dos seus autores e os que não abordassem directamente o tema em estudo. Resultados: Na literatura consultada, a principal causa apontada para as lesões é de origem microbiana: a microbiologia de lesões endo-perio combinadas, dominada por anaeróbios facultativos e/ou obrigatórios, reflete a microbiota da lesão endodôntica e periodontal em separado e permite infeção cruzada entre o canal radicular e a bolsa periodontal. Os tratamentos endodônticos inadequados, as infiltrações coronais, o atraso da colocação da restauração definitiva, as características anátomo-morfológicas do sistema de canais radiculares, as obturações anteriores, as técnicas de instrumentação e de obturação e a escolha dos materiais, são factores amplamente referidos na literatura que influenciam as falhas do tratamento. Enquanto a polpa mantém funções vitais, mesmo com infeção, a probabilidade desta causar problemas no periodonto é baixa; pelo contrário, a necrose pulpar já é, frequentemente, associada a inflamação do tecido periodontal. Conclusões: Como principal conclusão, deve ser salientado o facto da polpa e do periodonto se constituírem como uma unidade biológica contínua, com múltiplas vias de comunicação, pelo que as doenças pulpares e as doenças periodontais podem influenciarse mutuamente. Pode, igualmente, ser realçado que as doenças endodôntica, periodontal e endodôntica- -periodontal podem apresentar os mesmos sintomas, aspectos radiográficos e sinais clínicos muito semelhantes, sendo que o tratamento e o prognóstico dependem, em primeiro lugar, do diagnóstico da doença endodôntica e/ou periodontal específica, pelo que os principais fatores a considerar na tomada de decisão do tratamento devem ser a vitalidade pulpar e também o tipo e extensão da doença periodontal. A classificação mais utilizada pela maioria dos autores e nos livros da área é a de Simon et al. 1972, que se baseia nos fatores etiológicos e descreve o desenvolvimento deste tipo de lesões; no entanto, os seus fatores etiológicos e os seus padrões patológicos são muito diversos, facto que, ainda, não permitiu o aparecimento de uma classificação totalmente satisfatória. Introduction: This study aimed to conduct a literature review regarding the perio-endo disease. To this extent, the biological relationship between the pulp and the periodontium were explored, including the existing means of communication, the factors that contribute to its onset, persistence and / or worsening, and highlighting the etiological factors and the influence of pulp pathology in the periodontium and vice versa. The main classifications of endo-perio lesions were presented along with the problem of diagnosing, treating and the prognosis of teeth involved. Materials and Methods: This review was performed with the time limit of 1975 to 2014, using the search engine Google and several databases such as Medline / PubMed, B-on, ScienceDirect using the following keywords: endo-perio lesions, classification of endoperio lesion, microbiology, pathways of communication, diagnosis in endo-perio lesions, treatment of endo-perio lesions. After reading the abstracts, the selection of articles was performed according to the specificity of the topic and the time limits mentioned above. Books in the field of endodontics were also consulted in the FCSUFP library. Excluding criteria was used on articles that needed purchase and to which there was no response on the part of their authors and on the ones that didn’t directly address the topic under study. Results: In this review, the main reason given for the lesions is of microbial origin: the microbiology of combined endo-perio lesions that are dominated by facultative and / or strict anaerobes, reflects the microbiota of endodontic and periodontal lesion separately and allows cross-infection between the root canal and the periodontal pocket. Inadequate endodontic treatment, coronal leakage, delay placing the final restoration, the anatomical and morphological characteristics of the root canal system, previous fillings, technical instrumentation and obturation, and the choice of materials, are widely referred to factors in literature that influence treatment failures. As long as the pulp retains vital functions, even when infected, the likelihood of this infection causing problems in the periodontium is low; in contrast, pulp necrosis is often associated with tissue inflammation of the periodontium. Conclusions: As the main conclusion, it should be emphasized that the pulp and periodontium are constituted as a continuous biological unit, with multiple communication paths, so the pulp diseases and periodontal diseases can have a mutual influence. It may also be noted that the endodontic, periodontal and endodontic-periodontal diseases may present the same symptoms, radiographic features and similar clinical signs, therefore the treatment and prognosis depend, firstly on the diagnosis of the specific endodontic and/or periodontal disease, and the main factors to consider in making the decision to treat should be the pulp vitality and also the type and extent of periodontal disease. The classification used by the majority of authors and books in the area is that of Simon et al. 1972, which is based on etiological factors and describes the development of such injuries; however, their etiological factors and their pathological patterns are very diverse, which makes it difficult to have a fully satisfactory classification.

This project required developing new practical routes towards pyrroles and could help the project of total synthesis of (-)-rhazinilam. In chapter one, the most widely used methods for constructing the pyrrole ring system are reviewed. The origins of this project were to investigate further uses for the iodocyclization reactions developed previously. In chapter 2, a new approach to such highly substituted pyrroles in which the key step is a 5-endo-dig halocyclisation of substituted homopropargylic sulfonamides was successfully achieved. Key to the success of this novel method is the rapid preparation of suitable starting materials, from 1-alkynes by sequential formylation and condensation with a tin(II) enolate of vV-tosyl glycinate. Also, in chapter 2, a transition metal-catalyzed cyclisation using silica-supported silver nitrate was investigated and found to be effective. The reaction is clean and proceeds in quantitative yields. Obviously this fundamental research project is of a great interest because (-)-rhazinilam acts as an antimitotic agent like taxol, which are powerful anticancer agents. Different strategies of this approach are reviewed in chapter 3. In chapter 4 and 5, various aspects of separate approaches to the anti-tumor compound rhazinilam are described. In the former, both the synthesis of suitable 3-arylpyrrole cores and strategies for extending this methodology by the incorporation of a suitable substituent based on a cleavable cyclohexene are outlined. In the second section, chapter 5, similar issues are addressed but, in contrast, the Ag(I) methodology is used to construct a suitable arylpyrrole, the synthesis of which also features construction of the key precusor by aziridine ring hydrolysis. An efficient route to an enantiopure precusor of the necessary side chain is also described. This thesis is completed by a full experimental section and reference list.

Especialista en terapias de arte
Tesis restringida por petición de su autora hasta septiembre 2016.
La práctica profesional se basó en aplicar el arteterapia con uso de materiales artísticos, como una terapia de apoyo, a una mujer de 50 años con severa depresión, en su fase final de tratamiento realizado en un centro de salud mental, consecuencia de una niñez y adolescencia sin el apoyo afectivo, principalmente de su padre hasta los 11 años en que falleció; y de su madre hasta su mayoría de edad. Información obtenida tanto por la profesora de arte como de la ficha médica de la tratada. En base a esto, se definieron los objetivos generales y específicos a realizar para obtener los resultados, para lo cual previo fue necesario describir el proceso terapéutico, analizar los resultados del proceso, así como el comportamiento de la paciente y el terapeuta con el uso de los materiales y con el espacio terapéutico. Se fue observando cómo la materialidad fue importante en este proceso, donde la arpillera y el bordado fueron los principales materiales en el tratamiento de la paciente. Propiedades de los materiales. Tema que irá siendo detallado a través de esta monografía. El objetivo fue lograr que la paciente liberara sus traumas, controlara sus dolores y ordenara sus emociones, para poder comprender sus temores y angustias que darán respuesta a sus temores y angustias, por medio del uso del material y la relación terapéutica. Obteniendo finalmente, comprender los problemas que le aquejaban y aceptar su participación en ellos.

Projeto de Pós-Graduação/Dissertação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Medicina Dentária
A inter-relação entre a doença endodontica e a doença periodontal tem gerado, ao longo do tempo, assim como nos dias de hoje, muitas dúvidas, especulações e controvérsias. Tanto a doença endodontica como a periodontal podem ser bastante difíceis de diagnosticar e, sabemos que ambos assumem a responsabilidade de mais de 50% da morbilidade e perda dentária. O objectivo deste trabalho é assim abordar os vários conceitos relacionados com as lesões endo-perio, mas fundamentalmente a sua classificação e diagnóstico. Para a elaboração deste trabalho foi utilizado o motor de busca MEDLINE/Pubmed, com as seguintes palavras-chave “diagnosis”, “endo-perio injuries”, “classification”, “treatment”, “prognosis”, “pulp” “periodonto” and “etiology”. Estas palavras foram associadas de várias formas, utilizando artigos num intervalo de tempo entre 1974 e 2014. Num dente com sintomatologia, a dor pode ser de origem periodontal e/ou pulpar. A natureza da dor é, normalmente, o primeiro indício para a determinação da etiologia do problema. A avaliação clínica e radiográfica vai ajudar a detectar, com maior certeza, a origem do problema. É comum em alguns casos a patologia pulpar causar o envolvimento periodontal e vice-versa. Isto acontece porque, desde o desenvolvimento do gérmen dentário que se formam estruturas como os túbulos dentinários, canais principais e acessórios que permitem a comunicação entre a polpa e o periodonto. Favorecendo assim, o transporte de substâncias nocivas entre ambos os complexos. Na literatura, existem várias classificações das lesões endo-perio que vão desde as simples às mais complexas, e que se baseiam na sua etiologia e prognóstico. O prognóstico é favorável quando o tratamento é adequado e de acordo com o estado da doença, podendo ser exclusivamente endodontico, periodontal ou combinado. Com a realização deste trabalho podemos concluir que as lesões endo-perio são encontradas em casos de condição dentária comprometida, o seu diagnóstico torna-se por vezes difícil de estabelecer, mas é vital a importância de fazê-lo correctamente para, consequentemente, realizar um plano de tratamento adequado. For a long time now the inter-relation between endodontic disease and periodontal disease had been raising many doubts, speculation and controversy. Either, one or the other, can be quite hard to distinguish and, as we know, both of them are responsible for over 50% of dental morbidity. That said, the main goal of this working paper is to approach the various concepts related to endo-perio injuries, but, mostly, their classification and diagnosis. The search engine MEDLINE/Pubmed was used to elaborate this working paper. The search contained the following key words: “diagnosis”, “endo-perio injuries”, “classification”, “treatment”, “prognosis”, “pulp” “periodonto” and “etiology”. These words were related in several ways, using articles between the years of 1974 and 2014. At a tooth with symptomatology, the pain can have periodontal and/or pulpar origin. The nature of the pain is, usually, the first sign to determinate the problem’s etiology. The clinical examination and radiographic will help diagnose, with more certainly, the nature of the problem. In some cases, it is common that the pulp pathology causes the periodontal envelopment and vice-versa. This happens because the dental germen’s development creates structures such as dentinal tubules, major and accessory canals that allow the communication between the pulp and the periodonto. This way, the transportation of harmful substances between both complexes is facilitated. In literature a various number of endo-perio injuries’ classifications can be found, from the simplest to the most complex, all based in its etiology and prognosis. A prognosis is favorable when the treatment suits the degree of the disease. It can be exclusively endodontic, periodontal or combined. After writing this working paper, we can conclude that the endo-perio injuries are occasionally found in cases of compromised dental conditions and it is sometimes hard to come up with the diagnosis, but do it correctly it’s crucial so that we can provide with an adequate treatment plan.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2011.
Vita. Cataloged from PDF version of thesis.
Includes bibliographical references.
Chapter I. Introduction to the Ladder Polyethers. We introduce the bioactivity of the ladder polyether natural products and provide an overview of the puzzle that is their biogenesis. Cascades of endo-selective epoxide opening inspired by the biosynthetic proposal and promoted by simple neutral water can provide efficient access to these compounds. Chapter II. Water-Promoted Epoxide Opening Accommodates Methyl Substitution. ... Methyl (Me) substitution poses a challenge to the achievement of endo-selective epoxide-opening cascades, as these groups can direct the regioselectivity of epoxide opening. Water as reaction solvent and promoter overcomes such directing effects and enables the incorporation of proximally Me-substituted epoxides into endo-selective cascades. However, Me-substituted epoxides do reduce the overall efficiency of cascades. Chapter III. Kinetics of an Epoxide-Opening Cascade Promoted by Neutral Water. Evidence for a Stepwise Mechanism. ... Detailed investigation of the kinetics of an endo-selective epoxide-opening cascade in water reveals a stepwise mechanism, not a concerted one. While the first step proceeds with poor rate and selectivity, the second cyclization, which is templated by a fused THP diad, proceeds with excellent endo selectivity. Chapter IV. Preliminary Investigation of a Dioxane Template for Endo-Selective Epoxide-Opening Cyclization. ... Use of a 1,3-dioxane as template ring, a methylene acetal engenders endoselective epoxide opening under both acidic and basic conditions. Cyclization in neutral water proceeds with superb endo selectivity. Chapter V. Progress Toward the Synthesis of Gambierol via Endo-Selective Epoxide-Opening Cascades Promoted by Water. ... We report progress toward the biomimetic total synthesis of the ladder polyether gambierol. The FGH ring system has been synthesized in a 20 step longest linear sequence, via an endo-selective epoxide-opening cascade promoted by water. Chapter VI. Conclusion: Potential Implications of the Foregoing Work on the Biosynthesis of the Ladder Polyethers. We summarize lessons learned from in vitro emulation of the hypothesized biosynthesis of the ladder polyethers and speculate on the possibility of ring junction methylation subsequent to the epoxide-opening cascade step.
by Christopher J. Morten.
Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2010.
Vita. Cataloged from PDF version of thesis.
Includes bibliographical references (p. 108-112).
[image] The proposed biogenesis of the ladder polyethers features a dramatic series of epoxide opening reactions, elegantly accounts for the structural and stereochemical features of all related natural products, and, in principle, could significantly simplify the synthesis of these extraordinarily complex molecules. In practice, however, such cascades are strongly disfavored, and non-natural directing groups must be covalently attached to each epoxide to overcome this inherent bias. We report herein a general method for directing group-free cascades that also supports the postulated biosynthesis. The two salient aspects of this strategy are a single design principle (a template) and a promoter that both donates and accepts hydrogen bonds. Water is the superior promoter, and it is most effective at approximately pH 7.
by Ivan Vilotijević.
Ph.D.

The primary objective of this research project was to develop a novel protocol for the synthesis of densely functionalized optically enriched indanes through a chiral cation directed 5-endo-trig ring closure. In chapter two, a convergent strategy for the construction of the cyclization precursors is reported, which employs two easily adapted fragments. In chapter three, a range of quaternary ammonium salts are screened to establish the optimal phase-transfer conditions for this system. A variety of substrates were evaluated to probe the scope and limitations of this methodology. Finally, two potential mechanistic pathways for this enigmatic process are outlined and discussed in chapter four.

Electron Nuclear DOuble Resonance (ENDOR) spectroscopy has been employed in this Thesis to study a range of paramagnetic metal-ligand complex systems. The investigations focussed on the observation of conformational changes, solvatochromic effects and weak diastereomeric interactions of the complexes in frozen solution. Using a combination of angular selective ENDOR spectroscopy and DFT calculations, the structure and conformations of the Vlv=0(acac)2 complex in coordinating and non-coordinating solvents was examined. In the non-coordinating solvent (CD2CI2) the complex was found to adopt the expected square pyramidal structure, where the VOH lg distances and coordinates obtained by DFT and ENDOR were in excellent agreement with each other confirming the expected structure. More importantly, in coordinating solvents (such as pyridine) two different stereoisomers of the resulting Vlv=0(acac)2(C5D< N) adduct, which differed in energy by only 3 kJmol"1, were readily identified and discriminated by ENDOR (PCCP 2002). Subtle changes to metal-ligand structures by solvatochromic effects were also examined using Vlv=0(salen) in both coordinating (DMF) and non-coordinating (CD2CI2) solvents. In the non-coordinating solvent (CD2CI2), the expected square pyramidal symmetry of the V=0 ion above the NNOO plane of the ligand was confirmed both by ENDOR and DFT. However, in the coordinating solvent (DMF), a subtle perturbation from square pyramidal structure was observed suggesting than DMF coordinated trans to the vanadyl oxo-ligand, pulling Vlv=0 back into the ligand plane. This was evidenced through analysis of the VO....H j{j distances determined by ENDOR and confirmed by DFT (Chem. Phys. Lett. 2003). ENDOR was also used to explore the weak enantioselective binding between vanadyl based chiral salen complexes (abbreviated to VO(Jacobsen) ) and chiral propylene epoxide. Differences in epoxide binding by enatiomers of the complex was evidenced by changes to the 'H epoxide derived peaks in the ENDOR spectra. These changes were assigned to the small structural differences between the diastereomeric metal-epoxide adducts. Simulation of the spectra revealed differences in the VO...lHepoxjde distances for the diastereomeric pairs, which was confirmed by DFT. While the epoxide molecule was very weakly coordinated, ENDOR measurements of the racemic complex in racemic epoxide nevertheless indicated the preferential coordination of the /- VO(Jacobsen) to /-epoxide. This demonstrates the unique power of the ENDOR technique to resolve weak chiral interactions for which EPR spectroscopy alone lacks sufficient resolution (./ACS 2004). Finally, the diastereomeric interactions between chiral amines and copper based chiral salen complexes (abbreviated to Cu(Jacobsen) ) was investigated, as a comparison with the previous weak interactions in the VO(Jacobsen)-epoxide case. Diastereomeric discrimination was once again evidenced by ENDOR. The slight differences in the Cu-amine distances, constrained by the chirality of the anchoring site, resulted in subtle difference in the spin densities to the ligand nitrogens, which was detected in the ENDOR experiment.

Nous avons synthétisé différentes dyades donneurs-accepteurs (D-A) π-conjuguées à base de fullerène pour des applications photovoltaïques dans lesquelles les unités D étaient soit des oligophenylenevinylenes (OPV) soit des oligophenyleneethynylene (OPE) et les unités A étaient le C60 ou un endofullerène du type Y3N@C80. Il y avait une exigence supplémentaire pour nos matériaux, à savoir qu’ils devaient s’auto-organiser en phases liquides-cristallines. Pour ce faire, toutes les unités D contenaient un promoteur mésogène afin d'induire le mésomorphisme de la dyade D- et donc de contrôler la morphologie des couches minces nécessaires à l’élaboraiton des cellules photovoltaïques grâce à une organisation supramoléculaire. En dehors de cela, nous avons étudié l’influence de la nature chimique du donneur (par exemple lyophile ou amphiphile), de la longueur des oligomères et de la multiaddition sur les propriétés photophysiques et sur l'auto-assemblage. Nous avons synthétisé une dyade OPE-Y3N@C80 qui est le premier dérive mésomorphe et photosensible de ce type de métallofullerène endohédral
We have synthesized different π-conjugated system-fullerene dyads for photovoltaic applications, where the donor units were either oligophenylenevinylene (OPV) or oligophenyleneethynylene (OPE) derivatives and for the acceptor, C60 or Y3N@C80 was used. There was an additional requirement for our materials: liquid crystallinity. All the donor units contained a mesogenic promoter in order to induce mesomorphism in the D-A dyad and to control the morphology of the prepared film through supramolecular organization. Apart from that, we investigated the effect of the chemical nature of the donor moiety (ie. lyophilic or amphiphilic), the oligomeric length and multiaddition on the photophysical properties and on the self-assembly. We have synthesized an OPE-Y3N@C80 dyad which is the first trimetallic nitride template endohedral metallofullerene derivative with mesomorphic and photoactive properties

Erwinia carotovora subsp. Carotovora (Ecc) and Erwinia carotovora subsp. Atroseptica (Eca) are plant pathogenic bacteria that cause soft rot disease of many plant species and blackleg disease of potatoes, respectively. Ecc and Eca attack plants by means of a group of extracellular plant tissue-degrading enzymes. which rapidly breaks down the pectic polymers that form a structurally important part of the plant cell wall, is considered central to soft rot pathogenesis. In this work, I isolated and studied the genes encoding this enzyme from Ecc and Eca. A clone library of Ecc strain EC14 was constructed using cosmid PLAFR3. This library contains 2,200 clones with an average insert size of 27 kilobases of DNA and included a proteolytic clone, five cellulolytic clones, and ten pectolytic clones. The proteolytic clone was used to complement a Tn5-induced protease mutant of Ecc; the complemented mutant was restored to near-wild type phenotype. Six of the pectolytic clones hybridized to a probe from a. previously isolated extracellular endo-pectate-pectate lyase gene from Ecc; one pectolytic clone had homology to a previously isolated clone encoding endo-polygalacturonase: three clones showed no relationship to either of the previously characterized Ecc pectolytic enzyme genes. A clone encoding the major endo-pectate lyase gene from Ecc was chosen for subcloning and further study. I used the plasmid vector pBR322 to construct a clone bank of Eca strain SRB; of the 1700 clones screened, five were pectolytic. Two of the Eca pectolytic. clones had homology to the Ecc endo-pectate lyase gene; upon examination, they proved to contain the same insert in opposite orientations. The Ecc endo-pectate lyase had a pI of 9. 5 and a molecular weight of 33,000; the analogous Eca endo-pectate lyase had a pI of 9.2 and a molecular weight of 31,000. Both enzymes required a divalent cation for activity (preferring Ca2+ over Mg2+ over Mn2+. The restriction endonuclease maps of the two clones did not have any tested sites in common. These differences suggest that although these two genes may have originated from a common ancestral gene, considerable divergence has taken place. I analyzed the fine structure of the Ecc endo-pectate lyase gene by DNA sequencing. The coding region of the gene is preceded by E. coli-type -10 and -35 sequences and encodes an unmodified protein of 281 amine acids. A typical secretion signal peptide is not present.
Ph. D.

The following thesis discusses the combined use of electron paramagnetic resonance (EPR) spectroscopy, electron nuclear double resonance (ENDOR) spectroscopy and density functional theory (DFT) calculations to investigate a number of transition metal catalyst systems the binding of epoxide molecules by a vanadyl analogue of the catalytically important metallosalen class of compounds the binding of a chiral aryl amine by a copper salen complex and the incorporation of copper(II) ions in aluminophosphate materials. Two classes of epoxide selectivity by a vanadyl salen derivative are presented here, the discrimination of the geometric isomers of 2,3-epoxybutane, cw-2,3-epoxybutane and /ra 5-2,3-epoxybutane by Ar,Ar'-bis(3,5-di-tert-butylsalicylidene)-l,2-diaminocyclohexa- ne-vanadium(IV) oxide ( VO(l) ) 1 and the stereoselectivity of epoxypropane, 1,2- epoxybutane, chloromethyloxirane and fluoromethyloxirane by VO(l) . In both cases it is shown that hydrogen-bonding interactions, including interactions between the epoxide oxygen atom and a hydrogen atom bonded to a stereocentre carbon atom of the complex are important in determining the binding mode, thus implicating the given stereocentre carbon atom in the transfer of chirality. In the geometric isomerism of 2,3-epoxybutane, steric arguments regarding the obstruction caused by the methyl groups made on the basis of the DFT structures explain the selectivity observed in the EPR/ENDOR spectra. In the chiral selectivity of the other epoxides, more complicated reasoning, based on tripodal weak hydrogen-bonding configurations involving the hydrogen atoms of the epoxide ring and the oxygen atoms of the complex ligand is required to fully explain the selectivity observed, with different selectivity effects in the more electronegative halogenated epoxides compared to the alkyl cases. The coordination of methyl benzyl amine to a series of analogues of Cu(l) with various levels of tert-butylation, to model the steric effects in this interaction is studied here using DFT methods to explain the coordination preference for heterochiral pairings observed in the EPR spectra. Reasoning based on the preference of each enantiomer of the MBA to become involved in % - n interaction with alternate benzene rings of the complex, along with a slightly increased crowding of one ring over the other caused by the same hydrogen atom as implicated in determining selectivity in the epoxide study (above), namely the hydrogen atom bonded to one of the stereocentre C atoms, explains the selectivity observed in terms of n n interactions, also identifying the role of the stereocentre C atoms in conferring chirality. In combination, these studies demonstrate the importance of weak interactions, namely hydrogen-bonding andn-n interactions, in determining the binding configurations, and by extension the selectivity of these transition metal complexes. They also describe the nature of the involvement of the stereocentres of the complex in directing that selectivity, delineating a link between the chirality of the complex and that of the bound species in each case. The importance of using both EPR/ENDOR and DFT techniques in such studies, namely of explaining selectivity observed by EPR in terms of ENDOR and DFT derived geometry parameters is further explored in this thesis in the development of genetic algorithm routines to modify DFT-derived structures, by means of the ENDOR spectra simulated with the hyperfine parameters derived from a simple point-dipole model applied to the coordinates. The application of this process to a sample axial system, VO(acac)2, demonstrates the effectiveness of exploiting the complementary nature of the ENDOR and DFT techniques in this manner. Finally, a second copper study is reported here. This example is of a microporous aluminophosphate material, and concerns the incorporation of Cu11 ions into framework vs. extra-framework sites, a subject of some controversy. Here, evidence is presented for the ability of copper to distort the tetrahedral lattice into a distorted octahedral and a square- based pyramidal environment in which one or both of the remaining coordination sites is/are occupied by the templating molecules and water molecules, without rendering the lattice unstable, arguing in favour of framework site incorporation.

There has recently been an increase in the amount of work on the theoretical side of ENDOR spectroscopy which has tried to give a more detailed understanding of the complex spectra obtained from solid solutions. The work presented here is an attempt to show how much more information can be extracted from such spectra with only a minimal increase in the amount of experimentation required. A simulation program is presented which, based on a simple model, predicts the form of the variation of the ENDOR spectra when the field Bo, at which the experiment is performed, is varied within the span of the ESR spectrum. These theoretical results are compared with the results from a study of the complex bis-(pentan-2, 4-dionato) oxovanaduim (IV). The results indicate that not only can we obtain more accurate values for the principal elements of the hyperfine interaction tensors, but that we can extract information as to the relative orientation of the g axis system and the axis system of the hyperfine interaction tensor. two copper complexes, bis-(pentan-2,4-dionato) copper (II) and bis-(2,2,6,6-tetramethylheptan-3,5-dionato) copper (II), and these results are compared with results from solid solution ENDOR spectra of the two complexes obtained by the author and by other workers. The comparison indicates that a certain amount of reinterpretation is required in the case of the published work on the bis-(pentan-2,4-dionato) copper (II) complex.

Trabajo de Investigación Requisito para optar al Título de Cirujano Dentista
En patologías pulpares irreversibles, la endodoncia es el tratamiento de elección para evitar la extracción de la pieza afectada. Su éxito se basa principalmente en la desinfección del sistema de conductos radiculares. El propósito de este trabajo fue evaluar el efecto de Endox®, sobre la desinfección de conductos radiculares de piezas con necrosis pulpar séptica, sin el uso adicional de otros agentes comúnmente empleados para este fin. El principio por el que actúa Endox® se denomina electrofulguración, que consiste aplicar una corriente eléctrica de alta frecuencia en una fracción de segundo, que generaría daño a la materia orgánica. Objetivo: Establecer in vitro que el sistema Endox® produce una disminución de la microbiota total obtenida de conductos radiculares, en piezas con necrosis pulpar séptica, mediante el recuento de la microbiota total cultivada antes y después de su aplicación. Materiales y Métodos: Se seleccionaron 40 pacientes con diagnostico de necrosis pulpar séptica total en una de sus piezas dentarias. Se realizó la exodoncia correspondiente conformando 2 grupos de 20 dientes. Grupo 1: Endox®, Grupo 2: Hipoclorito de Sodio 5,25%. Se trepanaron las piezas y se tomaron muestras con conos de papel estériles, para cuantificar su contaminación inicial. Grupo Endox®, aplicación siguiendo instrucciones del fabricante. Grupo 2, irrigación con 5 ml de hipoclorito de sodio 5,25% por 2 minutos. Para los 2 grupos se tomaron nuevas muestras bajo las mismas condiciones que en el paso inicial. Todas las muestras fueron depositadas en medio de transporte RTF, frío, y llevados al laboratorio para su procesamiento. Fueron cultivadas por 10 días para realizar recuento de colonias formadas. Se comparó el resultado obtenido, antes y después de utilizar los métodos de desinfección. Resultados: La aplicación de Endox® disminuyó significativamente el recuento de UFC/ml de microbiota total, el que fue evaluado antes y después de la aplicación de este sistema (P=0,004). Existe diferencia significativa entre el recuento de la microbiota total antes y después de aplicar Endox® Conclusiones: Se obtuvo una diferencia significativa entre el recuento de la microbiota total antes y después de aplicar el sistema de desinfección mediante pulsos eléctricos de alta frecuencia Endox®

Les travaux présentés dans ce manuscrit ont permis dans un premier temps de développer avec succès deux nouvelles méthodes pour réaliser des cyclisations radicalaires 5-endo et dans un second temps d'illustrer le potentiel synthétique de la chimie radicalaire des xanthates, mise au point au sein du laboratoire, par son application à la synthèse de substances biologiquement actives. Dans la première partie, différentes approches permettant un accès aux γ-lactames par cyclisation radicalaire 5-endo sans l'utilisation de métaux lourds toxiques tel que l'hydrure de tributylétain ont été étudiées. L'originalité des deux systèmes développés réside dans l'oxydation du radical issu de la cyclisation. Ainsi, contrairement aux réactions induites par l'hydrure de tributylétain, différents γ-lactames insaturés peuvent être obtenus après déprotonation. Les travaux réalisés dans la deuxième partie ont permis l'élaboration de nombreux analogues des duocarmycines, qui ont fait l'objet de tests biologiques. Ces différents composés ont pu être préparés grâce à une synthèse convergente et efficace qui consiste à coupler un noyau alkylant avec un bras intercalant par formation d'une hydrazone. Différentes parties alkylantes ont été synthétisées rapidement grâce à l'application de la séquence d'addition-cyclisation radicalaire à partir de xanthate, précédemment développée au laboratoire. Une étude a également été menée pour tenter d'apporter des modifications à ces molécules. Enfin, nous avons préparé divers bras intercalants selon plusieurs méthodes. Nous avons ensuite couplé les différentes parties. Les molécules ainsi synthétisées ont révélé des activités cytotoxiques très prometteuses (IC50 ~ 0.5-1.2 µM). Cette étude prouve donc l'intérêt synthétique de la chimie radicalaire des xanthates.

Endo-β-mannanase is an endohydrolase enzyme responsible for the breakdown of mannan-containing polysaccharides common in the cell walls of many plants. The action of endo-β-mannanase in barley, its optimum temperature and pH for action, temporal and spatial localization, activity in the presence of hormones and sugars and its effect on the seed's mechanical strength were assayed. The development of a spectrophotometric assay for endo-β-mannanase detection was also trialed. The optimum temperature and pH for these experiments were found to be 37℃ and pH 7. Using these parameters, the endo-β-mannanase enzyme was found to be initially localized in the seed coat and moved through to the endosperm over time. The detected level of enzyme activity increased in the presence of gibberellic acid and glucose, or decreased when abscisic acid was added. Similar results were seen when the embryo was removed and the endosperm and seed coat were incubated in hormone- and sugar-containing media. The presence of exogenous endo-β-mannanase did not affect the mechanical strength of the seed but there was a strong correlation between increasing endo-β-mannanase activity and decreasing mechanical strength over time. The spectrophotometric assay for quantifying endo-β-mannanase in extracts showed promise but did not reach fruition due to unexplained sources of variation. The localization and regulation of endo-β-mannanase in barley were similar to those seen in other plants, such as tomato, lettuce and coffee. These findings have biotechnological applications within the brewery industry. By increasing the mobilization of reserves such as mannan, it is thought that the seedling can utilize this secondary carbohydrate source instead of, or at least supplementing, glucose which was mobilized from starch. This will theoretically reduce the starch and glucose lost during the malting period leaving a higher sugar content free for fermentation.

The principal aim of this project was to synthesise a range of functionalised heterocycles using novel transition metal promoted radical cyclisation reactions as an alternative to the well-established tin hydride method. On achieving this we hoped to successfully apply these methods towards the synthesis of natural product templates. In chapter two, a series of copper(l)-amine catalysts were employed to mediate the 5- endo-trig radical cyclisation of trichloroacetamides, which led to the formation of a variety of highly functionalised bicyclic y-Iactams in good to excellent yield. A variety of cyclisation precursors were examined. This work was also extended towards the synthesis of analogues of the heterocyclic ring fragment of non-peptide bradykinin inhibitor, L-755,807. In chapter 3, the reaction of a series of tertiary bromoacetamides with catalytic copper(I) bromide/N,N,N',N',N",N" -hexamethyltriethylenetetramine (Me6-tren) at room 'temperature is described. This reaction furnished regioisomeric mixtures of unsaturated pyrrolidinones via a highly efficient 5-endo-trig radical cyclisation reaction. We also illustrated that a variety of less activated secondary bromoacetamides undergo efficient 5-endo-trig radical cyclisation reactions to give a,l3-unsaturated monoene lactams under atom transfer conditions mediated by copper(l) bromide and tripyridylamine (TP A) in refluxing toluene. Changing the solvent for this reaction to 1,2-dichloroethane caused a,l3-unsaturated diene lactams to be produced instead. This approach was used towards the synthesis of analogues of the sesquiterpenic alkaloid, eremophilene y-Iactam. Chapter 4 describes an alternative route to constrained bicyclic ring systems mediated by ceric ammonium nitrate (CAN). In addition, the first reported 5-endo-trig radical cyclisation of l3-amido esters to afford functionalised y-Iactams was developed. This methodology was exploited in the production of analogues of the heterocyclic ring fragments of a' number of biologically active natural products.

Perchloroethylene (PCE) is a toxic contaminant that has been introduced into the environment over many years through industrial and agricultural wastes. Research has been done in the past to investigate PCE degradation by zero-valent iron (ZVI), green rust (GR) and a mixture of both. The combination of ZVI and green rust has been reported to be more effective for degrading PCE than either of them alone. Forming green rust electrochemically has the potential for depositing GR more effectively on the surface of ZVI where it will be able to more easily transfer electrons from ZVI to contaminants such as PCE. Therefore, the goal of this research was to determine the feasibility of electrochemically depositing green rust on zero-valent iron and to characterize it in terms of its composition, crystal properties and amount produced. XRD analysis was conducted to determine composition and crystal properties and a procedure was developed to measure the amount produced. Equipment was constructed to deposit green rust electrochemically onto ZVI. A chain of experiments with varying voltage, pH, time and amounts of ZVI were conducted to determine feasible experimental conditions for GR formation. Then, a method was developed to accurately measure the amount of surface oxides of iron deposited on the zero-valent iron substrate. This method was tested and found useful for measuring iron in: i) standard solutions of soluble iron with different concentrations of reagents; ii) suspensions with solid iron hydroxides by themselves; and iii) suspensions with solid iron hydroxides and ZVI. Electrochemical experiments were conducted and the amounts of iron hydroxides deposited on the ZVI surface were measured. XRD analysis of the deposits on the surface was conducted and the patterns of XRD-peaks were compared to that of type 2 – sulfate green rust.

Electron Paramagnetic Resonance (EPR) and Electron Nuclear Double Resonance (ENDOR) spectroscopies have been used to study the fundamental nature of chromium-based selective oligomerisation catalysts. A series of 'pre-catalyst' complexes were fully characterised CW-EPR revealed each complex to possess an axial g matrix (g > ge > g ) and superhyperfine coupling to two equivalent 31P nuclei, consistent with a low-spin cf species of approximate Cjv symmetry, where the metal contribution to the SOMO is primarily dxy. The isotropic component to the 31P coupling was of a larger magnitude in those Cr(I) complexes bearing PNP ligands than those bearing PCP, indicating that the phosphorus 3s character in the SOMO was higher for the former. CW-ENDOR demonstrated that subtle structural differences in the complexes, namely in the phenyl ring conformations, occurred as a function of ligand type. Pulsed experiments proved that the technique is valid and viable for further work on the activated system. Upon activation of the pre-catalyst with an alkylaluminium, four distinct paramagnetic centres were identified. A Cr(I) bis-arene complex was firstly detected it was found to form either via intramolecular co-ordination of the ligand phenyl groups, or preferentially via solvent-based arene co-ordination, if such groups were available. Two further species (I and III) were subsequently observed at low temperatures the spin Hamiltonian parameters extracted for both showed that a significant modification to the structure of the pre-catalyst had occurred. Half-field transitions indicated the possibility of a dimeric nature to Species III. ENDOR measurements detected an exceptionally large proton coupling in the activated system, possibly due to the co ordination of alkyl fragments to the metal centre. A final, fourth paramagnetic centre (Species IV), was detected and classed as an intermediate species, due to the greater similarity between its g and A matrices with those of the parent complex, than the other activated species. Finally, a preliminary investigation into analogous pre-catalyst complexes bearing N-heterocyclic carbene ligands was performed, due to their similar employment in oligomerisation catalysis CW-EPR spectra revealed information on both their electronic and structural natures.

O presente estudo teve por objetivo avaliar a difusão da temperatura desenvolvida na parede dentinária de raízes pelo uso de um aparelho eletrônico, recentemente lançado no mercado, denominado ENDOX® . É um sistema de tratamento endodôntico digital de eletrofulguração e que tem duas finalidades:- a) localizador apical por impedância, marcando o comprimento de trabalho – no terço apical assinala quanto se está próximo da constrição apical; e, b) desinfecção do canal radicular por meio de corrente de alta freqüência (600 kHz), vaporizando o eventual conteúdo do canal, devido a fulguração eletrônica de alta intensidade e freqüência, em menos de um décimo de segundo. Foram utilizados 40 caninos escolhidos pela sua anatomia, ápices afilados e arredondados. Cada grupo de 20 dentes foi subdividido em dois variando a intensidade da radiofreqüência aplicada nos diversos pontos da raiz: terços cervical, médio, apical e ápice. A freqüência aplicada foi a recomendada pelo fabricante, 600 kHz por 1/10 de segundo chamada de padrão e com um aumento de intensidade de 20%, 720 kHz. Os resultados obtidos foram submetidos a tratamento estatístico com nível de significância de 5%, utilizando análise de variância (ANOVA) e teste de Tukey. A diferença de temperatura entre os tipos de raízes é de aproximadamente 1ºC quando se compara as afiladas com as arredondadas. Entre os terços radiculares há um aumento progressivo da temperatura de cervical para o ápice. As médias da diferença de temperatura em ºC foram avaliados de acordo com as interações entre formato, terços radiculares e intensidade de radiofreqüência. Nas condições do experimento verificou-se que a diferença entre as temperaturas iniciais e finais não gerou calor excessivo na superfície radicular, não havendo diferença estatística significante entre raízes arredondadas e afiladas. Há uma progressão das temperaturas médias do terço cervical até o ápice sendo significantes independentemente do formato das raízes e da radiofreqüência. Houve diferença estatística significante observada nas interações de terços, formato radicular e diferente intensidade de radiofreqüência, entre ápice e terço médio. Nas raízes afiladas com aumento de radiofreqüência há diferença entre todos os seus terços. Concluiu-se que, nas limitações do experimento in vitro, o aumento de temperatura variou em média 10ºC, independente do formato radicular e intensidade de freqüência, portanto dentro dos limites tolerados para a reparação óssea. É recomendável utilizar a intensidade de freqüência padrão para melhor controle da temperatura em níveis baixos.
The present study aimed to evaluate the temperature diffusion on the dentin wall of root canals, using an electronic device recently placed in the market denominated ENDOX®. A digital electro fulguration system for endodontic therapy designed to reach two purposes:- a) defining the correct endodontic work length through an impedance apical locator; and, b) promote root canal disinfection, vaporizing root canal content in less then a decimal of a second by electronic fulguration of high intensity and frequency current (600 kHz). This study comprised 20 maxillary canines and 20 mandible canines, chosen for their apical taper or rounded anatomic characteristic. Each group of 20 teeth was then subdivided in two, varying the radiofrequency intensity applied on the diverse root points. Four different root areas were established for radiofrequency application: cervical third, medium third, apical third and the apex itself. Following the manufactures recommendation, the frequency applied, was the standard one, that is, 600 kHz for 1/10 of a second and with an increase of 20%, 720 kHz. The results were submitted to statistical treatment at 5%significance, variance analysis (ANOVA) and Tukey test. When comparing taper to rounded root types, the temperature difference between them was approximately 1°C. As to the radicular root thirds, progressive temperature increase was observed from cervical area to the apex. The average differences of temperature in °C were evaluated considering shape, radicular thirds, and radiofrequency intensity. Under the experiment condition, it was observed that the difference between initial and final temperature did not generate excessive heat on the root surface and also revealed no significant statistical difference between taper or round roots. There is a progressive rise of average temperatures from the cervical to the apical third that is significant, independently from root shape or radiofrequency. Significant statistical findings were noted involving the interaction of the root thirds, root shape and different radiofrequency intensity between the apex and the root’s medium third area. An increase of radiofrequency on the taper root shapes caused differences in all its roots areas. It was concluded that, within the limitations of this in vitro experiment, the temperature rise varied in average 10ºC, independently of root shape and frequency intensity therefore, under tolerable limits for bone repair. The standard frequency intensity is recommended in order to control temperature at lower levels.

Orientador: Daniele Botticelli
Banca: Wilson Roberto Poi
Banca: Idelmo Rangel Garcia Júnior
Banca: Luiz Antônio Salata
Banca: Thais da Silveira Rodrigues
Resumo: Objetivo: avaliar a influência da instalação de implantes em alvéolos imediatamente após a extração do elemento dental na regeneração dos tecidos peri-implantares com implantes de diferentes configurações Material e métodos: Nos alvéolos distais dos quartos pré-molares mandibulares de cães, imediatamente após as extrações das raízes dentais, foram instalados implantes cilíndricos com 3,3 mm de diâmetro (grupo controle) e implantes cônicos com 5,0 mm de diâmetro (grupo teste). Foram avaliados histologicamente a regeneração dos tecidos duros e moles peri-implantares após 4 meses do procedimento cirúrgico. Resultados: Todos os implantes apresentaram-se osseointegrados ao tecido ósseo maduro mineralizado. A crista óssea alveolar sofreu reabsorção tanto no grupo teste como controle. A superfície óssea vestibular dos implantes do grupo teste (cônico; 3,6 mm) apresentou maior grau de reabsorção em comparação ao grupo controle (cilíndrico; 1,6 mm). As dimensões dos tecidos moles apresentaram-se semelhantes em ambos os grupos. No entanto, em relação ao ombro do implante, a mucosa peri-implantar localizou-se mais apicalmente no grupo teste em relação ao grupo controle. Conclusão: Este estudo confirmou que a distância entre a superfície do implante e o contorno externo da crista óssea alveolar vestibular influenciou no grau de reabsorção da tábua óssea vestibular. Conseqüentemente, em relação ao ombro do implante, a mucosa peri-implantar será estabelecida em um nível mais apical, se a distância entre a superfície do implante e o contorno externo da crista óssea alveolar for menor
Abstract: Aim: the aim of the present experiment was to study the influence of implant installation into sockets immediately after tooth extraction on the healing periimplant tissues with implants of various configurations. Material & methods: Transmucosal cylindrical 3.3mm in diameter implants in the control sites, and conical 5.0mm in diameter in the test sites, were installed into the distal socket of the forth mandibular premolars in dogs immediately after tooth extraction. After 4 months, the hard and soft tissue healing was evaluated histologically. Results: All implants were integrated in mineralized mature bone. Both at the test and control sites, the alveolar crest underwent resorption. The buccal bony surface at the implant of the test sites (conical; 3.6mm) was more resorbed compared to the control sites (cylindrical; 1.6mm). The soft tissue dimensions were similar in both groups. However, in relation to the implant shoulder, the periimplant mucosa was located more apically at the test compared to the control sites. Conclusion:The present study confirmed that the distance between the implant surface and the outer contour of the buccal alveolar bony crest influenced the degree of resorption of the buccal bone plate. Consequently, in relation to the implant shoulder, the peri-implant mucosa will be established at a more apical level if the distance between the implant surface and the outer contour of the alveolar crest is small
Doutor

Les nucleases formen una família de gens conservats evolutivament, que s’han involucrat en la mort cel·lular programada i en la proliferació cel·lular en eucariotes. Una de les nucleases mitocondrials més estudiades és EndoG, la qual va ser identificada pel nostre grup com a nucleasa implicada en degradació de l’ADN al miocardi durant la isquèmia. Tot i així, també presenta una funció rellevant en la fisiologia del cor, ja que la pèrdua de funció d’Endog en cardiomiòcits causa un augment de la massa ventricular esquerra. Recentment, el nostre laboratori ha descobert una funció d’EndoG relacionada amb la proliferació cel·lular. En els darrers anys s’ha suggerit que la nucleasa mitocondrial ExoG, paràleg d’EndoG en eucariotes superiors, podria dur a terme funcions similars a EndoG. Tot i així, encara no s’ha investigat la possible interdependèndia entre ExoG i EndoG tant a nivell d’expressió com en la seva funció sobre la proliferació. D’altra banda, TatD va ser descoberta com una nucleasa relacionada amb l’execució de la mort cel·lular programada en C. elegans. La disminució de TatD en el nematode produeix un fenotip semblant a l’observat amb el silenciament d’Endog. No obstant això, la seva funció en mamífers és desconeguda. En aquest treball es demostra que EndoG, ExoG i TatD tenen una expressió tissular diferencial entre elles. De les tres nucleases, només ExoG es troba més expressada en teixits neonatals respecte als adults (a excepció del cervell) suggerint un paper en el desenvolupament. Dels teixits analitzats, EndoG abunda principalment en el cor, ExoG en cervell i TatD té una distribució homogènia entre els diferents teixits. En quant a la localització subcel·lular, EndoG i ExoG són mitocondrials mentre que TatD, sorprenentment, és citosòlica. Tant la reducció d’Endog com Exog limita la proliferació cel·lular en línies no tumorals i en cultius primaris tridimensionals de glàndules d’un model de càncer d’endometri. En canvi, la disminució de l’expressió de Tatd no té cap efecte en la proliferació. A diferència d’EndoG, ExoG i TatD no canvien de compartiment cel·lular ni participen en la degradació de l’ADN nuclear sota isquèmia experimental en cardiomiòcits ni tampoc en models cel·lulars depenents de caspases. També hem demostrat que ExoG i EndoG regulen la mida dels cardiomiòcits probablement per mecanismes comuns, mentre que TatD no hi és implicada. La generació i estudi del nou model murí Tatd-/- demostra que aquest gen no és essencial per la viabilitat i fertilitat del ratolí. Els ratolins Tatd-/- presenten canvis en l’expressió de diversos transcrits a cor i a cervell que suggereixen un rol en processos que impliquen transport de proteïnes i senyalització cel·lular en aquests teixits. L’anàlisi conductual d’aquest model de ratolí revela dèficits locomotors compatibles amb la fatiga, sense símptomes de depressió i ansietat. En conjunt, les nostres dades mostren que ExoG i EndoG tenen funcions comunes en la regulació del creixement dels cardiomiòcits i en la proliferació cel·lular i que TatD podria estar implicada en la regulació de processos de transport de proteïnes al cor i al cervell, essent important per una correcta funció motora.
Las nucleasas forman una familia de genes conservados evolutivamente, que se han involucrado en la muerte celular programada y en la proliferación celular en eucariotas. Una de las nucleasas mitocondriales más estudiadas es EndoG, la cual fue identificada por nuestro grupo como nucleasa implicada en degradación del ADN en el miocardio durante la isquemia. Sin embargo, también presenta una función relevante en la fisiología del corazón, ya que la pérdida de función de Endog en cardiomiocitos causa un aumento de la masa ventricular izquierda. Recientemente, nuestro laboratorio ha descubierto una función de EndoG relacionada con la proliferación celular. En los últimos años se ha sugerido que la nucleasa mitocondrial ExoG, paráloga de EndoG en eucariotas superiores, podría llevar a cabo funciones similares a EndoG. Sin embargo, aún no se ha investigado la posible interdependencia entre ExoG y EndoG tanto a nivel de expresión como en su función sobre la proliferación. Por otra parte, TatD fue descubierta como una nucleasa relacionada con la ejecución de la muerte celular programada en C. elegans. La disminución de TatD en el nematodo produce un fenotipo similar al observado con el silenciamiento de Endog. Sin embargo, su función en mamíferos es desconocida. En este trabajo se demuestra que EndoG, ExoG y TatD tienen una expresión tisular diferente entre ellas. De las tres nucleasas, sólo ExoG se encuentra más expresada en tejidos neonatales respecto a los adultos (a excepción del cerebro) sugiriendo un papel en el desarrollo. De los tejidos analizados, EndoG abunda principalmente en el corazón, ExoG en cerebro y TatD tiene una distribución homogénea entre los diferentes tejidos. En cuanto a la localización subcelular, EndoG y ExoG son mitocondriales mientras que TatD, sorprendentemente, es citosólica. Tanto la reducción de Endog como Exog limita la proliferación celular en líneas no tumorales y en cultivos primarios tridimensionales de glándulas de un modelo de cáncer de endometrio. En cambio, la disminución de la expresión de Tatd no tiene ningún efecto en la proliferación. A diferencia de EndoG, ExoG y TatD no cambian de compartimento celular ni participan en la degradación del ADN nuclear bajo isquemia experimental en cardiomiocitos ni tampoco en modelos celulares dependientes de caspasas. También hemos demostrado que ExoG y EndoG regulan el tamaño de los cardiomiocitos probablemente por mecanismos comunes, mientras que TatD no está implicada. La generación y estudio del nuevo modelo murino Tatd-/- demuestra que este gen no es esencial para la viabilidad y fertilidad del ratón. Los ratones Tatd-/- presentan cambios en la expresión de varios transcritos en corazón y cerebro que sugieren un rol en procesos que implican transporte de proteínas y señalización celular en estos tejidos. El análisis conductual de este modelo de ratón revela déficits locomotores compatibles con la fatiga, sin síntomas de depresión y ansiedad. En conjunto, nuestros datos muestran que ExoG y EndoG tienen funciones comunes en la regulación del crecimiento de los cardiomiocitos y en la proliferación celular y que TatD podría estar implicada en la regulación de procesos de transporte de proteínas en el corazón y el cerebro, siendo importante para una correcta función motora.
Nucleases are a family of evolutionarily conserved genes, which have been implicated in programmed cell death and cell proliferation in eukaryotes. One of the most studied mitochondrial nuclease is EndoG, which was identified by our group as a nuclease involved in DNA degradation in the myocardium during ischemia. However, it also plays an important role in the physiology of the heart, as the loss of Endog function in cardiomyocytes causes an increase in left ventricular mass. Recently, our laboratory has discovered a novel EndoG function related to cell proliferation. It has been suggested in recent years that ExoG mitochondrial nuclease, a paralog of EndoG in higher eukaryotes, may perform similar functios to EndoG. However, the interdependence between ExoG and EndoG both in terms of expression and its function on proliferation has not yet been investigated. On the other hand, TatD was discovered as a nuclease related to the execution of programmed cell death in C. elegans. TatD silencing in the nematode produces a phenotype similar to that observed with Endog silencing. However, its function in mammals is unknown. EndoG, ExoG and TatD have different tissue expression between them. Interestingly, ExoG is found to be more expressed in neonatal tissues than in adults (except the brain) suggesting a role in development. EndoG is mainly expressed in heart, whereas ExoG is highly expressed in brain, and TatD has a homogeneous distribution among the analyzed tissues. In terms of subcellular localization, EndoG and ExoG are found in mitochondria, but TatD is a cytosolic protein. Both Endog and Exog reduction limit cell proliferation in non-tumor lines and in three-dimensional primary cultures of an endometrial cancer model. In contrast, decreased Tatd expression has no effect on proliferation. Unlike EndoG, ExoG and TatD do not change cell compartment or participate in the degradation of nuclear DNA under experimental ischemia in cardiomyocytes or in caspase-dependent cell models. We have also shown that ExoG and EndoG, but not TatD, regulate the size of cardiomyocytes probably through common mechanisms. The generation and study of the new mouse model Tatd-/- shows that this gene is not essential for the viability and fertility of the mouse. Tatd-/- mice exhibit changes in the expression of various heart and brain transcripts that suggest a role in several processes involved in protein transport and cell signaling in these tissues. Behavioral analysis of this mouse model revealed locomotor deficits compatible with fatigue, without symptoms of depression and anxiety. Taken together, our data show that ExoG and EndoG have common functions in cardiomyocyte growth and cell proliferation, and TatD could be involved in the regulation of protein transport in heart and brain, being important for a normal motor function.