Magister Chirurgiae Dentium - MChD / Aim: The aim of the study was to investigate whether a correlation exists between the intra- operative position of the Inferior Alveolar Nerve (IAN) and the nerve position as noted on a pre-operative Cone Beam Computer Tomography (CBCT) scan in patients requiring Bilateral Sagittal Split Osteotomy (BSSO) of the mandible. Introduction: The BSSO of the mandible is of fundamental importance in the correction of dental facial deformities. The main post-operative complication of a BSSO of the mandible is Neurosensory Impairment (NSI). To avoid possible NSI it is important to have as much pre- operative information as possible. In this regard, pre-operative CBCT scans can provide the surgeon with an important assessment of the mandibular canal. This information on the buccolingual, superior and inferior position of the canal, especially in the region of the planned osteotomy, could help the surgical team to avoid IAN injury. Materials and Methods: This study correlates the pre-operative position of the IAN as indicated on a CBCT scan with the intra-operative IAN position in patients requiring BSSO of the mandible. Ten standardised cases were included in a prospective case series where twenty mandibular sides were assessed. Results: The variables assessed in this study were location of the nerve, age, sex, type of movement and side of mandible operated on. It was found that only the distance between the Inferior Alveolar Canal (IAC) and the lower border of the mandible are predictive of whether the IAN will be attached to - or free from - the proximal segment of the mandible. Conclusion: From the study it can be concluded that a CBCT scan is a useful and reliable modality in the pre-operative evaluation of patients undergoing BSSO especially with regard to the assessment and mapping of the mandibular canal.

Early prosensory specification to develop competence in the otic epithelium is disrupted by mutations of Eya1, Pax2, Sox2, Jag1, and Gata3. Mutations in these genes apparently disrupt sensory competence and may affect Atoh1 upregulation, a gene known to be necessary for sensory cell differentiation within the ear. How these genes interact with each other and other factors within the genetic network of the ear to refine and restrict sensory specification and impart competence to the developing organ of Corti is not known. These genes also interact with other factors expressed adjacent to or within the developing organ of Corti and provide the context to allow prosensory cells, after cell cycle exit, to appropriately respond to Atoh1 expression and differentiate as hair cells. Gata3 is expressed throughout the early placode. As ear development continues Gata3 is restricted to all prosensory areas except that of the saccule. In addition, it is expressed in a subset of delaminating neuroblasts. Gata3 continues to be highly expressed in the cochlear sensory epithelia as cells differentiate, and is expressed in all cells of the organ of Corti through adult. The human disorder caused by haploinsufficiency of Gata3 is known as Hypoparathyriodism, Deafness, and Renal dysplasia syndrome, and has been linked in mice to early hair cell death. I investigated the role of Gata3 in cochlear neurosensory specification utilizing a mouse Gata3 knockout model and a conditionally deleted Gata3 line combined with two cre driver lines (Foxg1cre and Pax2cre). Although both cre lines are expressed in the inner ear with only a slight difference in onset of expression there are major phenotypic differences. While the Foxg1cre:Gata3f/f deletion resulted in an ear closely matching that of the null mutant with a cochlear duct devoid of neurosensory cells, the Pax2cre:Gata3f/f cochlear duct contained patches of partially differentiated hair cells. Through the use of qRT-PCR and in situ hybridization of both mutants I was able to paint a picture of how Gata3 interacts with other prosensory genes to upregulate downstream genes. In particular, Atoh1, was downregulated but not absent with the loss of Gata3. Indicating that Gata3 is one of a set of factors necessary for the proper upregulation of Atoh1 in the cochlea.

To coordinate visual perception and motor control in daily life where we are constantly surrounded by motion, we are dependent on normal visuomotor capacity. One essential prerequisite for normal visuomotor capacity is smooth pursuit eye movements (SP). Infants born very preterm (VPT = born <32 gestational weeks) are at high risk of developing disabilities in higher brain functions i.e. perception, cognition, concentration and coordination. In this thesis visuomotor capacity was investigated in a cohort of VPT infants (n = 113) and compared to control groups of full term (FT) infants. Levels of SP were measured at 2 and 4 months’ corrected age (CA). At 8 months’ CA reaching capacity toward a moving object was evaluated as this represents an executive activity guided by vision that develops at an early age. Lower levels of SP were found in the VPT infants compared to FT controls. The VPT boys showed higher levels of SP compared to the VPT girls. In VPT infants without major neonatal morbidities lower levels of SP was found compared to the FT controls. No difference in total capacity of gaze tracking was found, although the VPT infants lagged the object more at 4 months’ CA and used more saccades at 2 months’ CA. With age the VPT infants’ SP levels increased, but with a wider dispersion compared to the FT controls, and the levels of SP at 4 months’ CA corresponded to the levels of the FT infants at 2 months.  A number of perinatal risk factors were found to be negatively associated to lower levels of SP, and this effect was more pronounced in VPT infants with multiple risk factors,.  When evaluating the capacity to reach a moving object at 8 months’ CA, the VPT infants showed significantly more bimanual reach and more curved reaching paths to catch the object as compared to the FT control group. In conclusion, a delayed visuomotor capacity was found in VPT infants compared to FT control infants at 2, 4 and 8 months’ CA. Some VPT infants with perinatal risk factors did not develop in levels of SP between 2 and 4 months’ CA.

La surdité neurosensorielle est définie par une atteinte de l’oreille interne, il résulte principalement d’une perte de cellules ciliées (CC). Chez les mammifères, ce processus est malheureusement irréversible. Le développement de la thérapie cellulaire a fait naître de nouveaux espoirs pour le traitement des surdités neurosensorielles. Les cellules souches d’origine embryonnaire ou adulte seraient capables de se différencier in vitro en progéniteurs otiques et de restaurer partiellement les fonctions auditives in vivo après transplantation. Cependant, les protocoles de différenciation in vitro des CC à partir de cellules souches sont insatisfaisants, et les signaux qui contrôlent ce phénomène restent mal connus. Ainsi, l’objectif de ce travail de thèse était d’étudier in vitro la différenciation des CC à partir de cellules souches pluripotentes induites humaines (hiPSC). Nous nous sommes intéressés à deux voies de signalisation majeures impliquées dans le développement de l’oreille interne in vivo, la voie Notch et la voie Wnt. Dans une première partie, nous avons montré que l’inhibition tardive de la voie Notch favorise la différenciation des hiPSC en CC. Dans une seconde partie, nous avons étudié le rôle de la voie Wnt dans la différenciation des hiPSC en cellules otiques. Nos résultats indiquent que l'inhibition de la voie Wnt durant la première phase d’induction favorise l'expression des marqueurs de la placode otique et initie la spécification des CC.Les travaux présentés dans cette thèse améliorent ainsi les protocoles de différenciation des hiPSC et suggèrent que ce type de cellules serait parfaitement adapté pour traiter les surdités neurosensorielles. / Neurosensory hearing loss is associated to inner ear disorders and degeneration of hair cells (HCs). Unfortunately, this process is irreversible in mammals. Currently, no curative treatment allows these cells to regenerate. For this reason, the development of cell therapy arose new hopes for the treatment of neurosensory hearing loss. Stem cells, either of embryonic or adult origin, seem able to differentiate in vitro into otic progenitors and to partially restore auditory functions in vivo. However, current protocols for in vitro differentiation of stem cells into HCs are unsatisfactory, and the signals that control this phenomenon remain poorly understood. Thus, the objective of this thesis was to study in vitro HC differentiation from human induced pluripotent stem cells (hiPSCs). We were particularly interested in two major signaling pathways involved in vivo in inner ear development, the Notch and Wnt signaling pathways.In a first part, we demonstrated that Notch inhibition during late otic differentiation enhances hiPSC differentiation into hair cell-like cells. In a second part, we studied the role of the Wnt signaling pathway during otic induction and HC specification. Our results indicate that Wnt inhibition during early otic induction promotes the expression of otic placode markers and initiate HC specification. The work presented here thus propose improved protocols to obtain HCs from hiPSCs, and suggest that this cell type is perfectly adapted for the treatment of neurosensory hearing loss.

No description available.

L’infection congénitale à CMV est la première cause de retard psychomoteur et de surdité, toutes causes confondues. En France, la prévalence de l’infection congénitale à CMV en France est estimée entre 0,6 et 0,7%. Parmi les enfants présentant une infection symptomatique, 10-20% des nourrissons font une forme sévère et décèdent, et 50 à 60% développent des lésions cérébrales avec un handicap neurologique parfois lourd consécutif à une microcéphalie, des calcifications intracrâniennes, des dilatations ventriculaires ou des convulsions. Certains parmi ceux-ci développeront aussi des séquelles neurosensorielles consécutives à une atteinte visuelle, auditive ou vestibulaire. La première partie de ce travail permet de décrire l’histoire et la physiopathologie des lésions de l’oreille interne chez l’homme. Les lésions de l’oreille interne sont évaluées chez 6 fœtus ayant une infection congénitale à CMV, âgés de 21 à 35 semaines d’aménorrhée, et corrélées aux atteintes centrales et viscérales. Dans la cochlée, les lésions prédominent au niveau de la strie vasculaire alors que l’infection est moins fréquente au niveau des cellules de l’organe de Corti. Les lésions vestibulaires sont plus florides que les lésions cochléaires et prédominent au sein de l’épithélium non sensoriel, en particulier des cellules sombres du saccule et de l’utricule, et de l’épithélium des canaux semi-circulaires. Ces lésions du compartiment endolymphatique de l’oreille interne pourraient être responsables d’une altération de la sécrétion du potassium et ainsi d’une modification de l’homéostasie de la cochlée et du vestibule par atteinte de la strie vasculaire et des cellules sombres. Secondairement, cela pourrait être responsable d’une dégénérescence de l’organe de Corti et des organes sensoriels vestibulaires. La survenue de la surdité neurosensorielle et de l’atteinte vestibulaire dépend très certainement de la durée et de l’intensité de l’infection virale et de l’inflammation. La deuxième partie de ce travail analyse les atteintes du système nerveux central qui n'ont pas fait l'objet d'étude détaillée. Nous avons sélectionné 9 fœtus de 23 SA à 38 SA dont la gestation a été interrompue devant une suspicion d’infection congénitale par le CMV. Ils ont été étudiés sur le plan foetopathologique standard, neuropathologiques, immunohistochimiques et morphométriques. La réplication virale productive prédomine dans le cortex et dans la région périventriculaire. Le virus infecte préférentiellement les cellules GFAP-positive et nestine-positive, mais aussi à un moindre degré les neurones, les cellules endothéliales et la microglie. La réaction immune microgliale et cellulaire cytotoxique semble insuffisante pour contrer l’importance de la dissémination virale suggérant son immaturité. Les malformations corticales sont de mécanismes variés et il existe une atteinte préalablement méconnue des bulbes olfactifs. Une troisième partie est consacrée au développement d’un modèle murin d’infection congénitale par le CMV visant à mieux comprendre les mécanismes physiopathologiques d'atteintes auditives et vestibulaires et à définir les modalités thérapeutiques. Les souriceaux infectés par injection intra-amniotique de virus MCMV développent une surdité dont le profil évolutif s’apparente à la clinique humaine. Les lésions histologiques se caractérisent par des atteintes de la strie vasculaire, de l’organe de Corti et du ganglion spiral. Ces différents axes de recherche complémentaires permettent de comprendre les mécanismes centraux et périphériques participant aux handicaps neurosensoriels chez les enfants atteints d’infection congénitale par le CMV. Les études cliniques et physiopathologiques complémentaires qui en découlent permettront d'affiner les cascades lésionnelles mis en jeu et d'optimiser la prise en charge de ces enfants / Congenital CMV infection is the leading cause of mental retardation and neurosensory-hearing loss. In France, the prevalence of congenital CMV infection is estimated between 0.6 and 0.7%. Amongst the children presenting with a symptomatic infection,10-20% of newborns will have a severe manifestation and die and 50-60% will develop cerebral lesions with a neurological handicap due to microcephaly, intracranial calcifications, ventricular dilations or convulsions. Some amongst these will also develop neurosensory sequelae such as visual, auditory or vestibular lesions. The first part of this work describes the history and the physiopathology of the inner ear lesions in human. The lesions were evaluated in 6 fetuses presenting with a congenital CMV infection, aged 21 to 35 gestational weeks and correlated to central and visceral lesions. In the cochlea, the lesions predominated in the stria vascularis whereas the lesions were les frequent in the organ of Corti. The vestibular lesions were more florid than cochlear lesions and predominated in the non-sensory epithelium in particular the dark cells of the saccula and the utricule and the epithelium of the semi-circular canals. These lesions of the endolymphatic compartment may be responsible of the alteration of the potassium secretion in the inner ear and therefore a modification of the homeostasis of the cochlea and the vestibule by lesion of the stria vascularis and the dark cells. With time, this could be responsible of the degeneration of the organ of Corti and of the vestibular sensory organs. The onset of neurosensory hearing loss and vestibular disorder probably depend upon the duration and the intensity of viral infection and inflammation. The second part of this work analyses the central nervous system lesions that have seldom been detailed. We have selected 9 fetuses aged 23-28 gestational weeks whose pregnancy has been interrupted due to congenital CMV infection. Standard fetopathological examination was completed with neuropathological, immunohistochemical and morphometric assessment. Viral replication predominated in the cortex and in the periventricular zone. The virus infects preferentially GFAP positive and nestin positive cells, but also, to a lesser degree, neurons, endothelial cells and microglia. Immune microglial and cytotoxic cellular responses seem insufficient to counter the importance of the viral dissemination suggesting immaturity. Cortical malformations are due to several mechanisms and olfactory bulbs are frequently infected. The third part describes the development of a murine model for congenital CMV infection in order to better understand the physiopathological mechanisms of the auditory and vestibular lesions and to define the guidelines for management. Infected newborn mice developed neurosensory-hearing loss with characteristics similar to human deafness. Histological lesions were mainly observed in the stria vascularis, the organ of Corti and the spiral ganglia. These different complementary research axes led to a better understanding of the central and peripheral mechanisms participating in the neurosensory handicaps of children with congenital CMV infection. Further clinical and physipathogical studies will allow a more precise comprehension of the lesional cascades and a optimization of the medical management of these children

Made available in DSpace on 2016-06-02T19:46:00Z (GMT). No. of bitstreams: 1 DissCKMRF.pdf: 3015571 bytes, checksum: cb74604e50a6fa10a49cf31400d74604 (MD5) Previous issue date: 2003-11-18 / Universidade Federal de Sao Carlos / Early identification of developmental delays in preterm infants is notable in various studies which emphasize the prevention of disabilities through the possibility of a better prognosis through specialized special education services or other rehabilitation measures. Intervention programs emphasize the integration of parental participation so they may take on coresponsibility for their children's development as an integral part of the treatment. The objective of this research was to evaluate the effectiveness of a program of early intervention with babies preterm with and without the parents' training. The participants in this study were 8 preterm infants with an average gestational age of 32 weeks and an average chronological age of 3 months and 6 days and their respective families. The study was done at the Neuropediatric Physiotherapy Unit at UFSCar and approved by the University Research Ethics Committee. The experimental research method was used and the participants were randomly divided into two separate groups: Control and Experimental. The Control Group was composed of 4 infants who received physiotherapy treatment but whose parents did not receive any orientation or training to work with their children at home. The Experimental Group was composed of 4 infants who received physiotherapy treatment and whose parents received orientation and training to continue the physiotherapy program at home. This four month study utilized the Operational Portage Inventory (OPI) and the Alberta Infant Motor Scale (AIMS) to measure the infants'development. All data from evaluation charts and videotapes of monthly evaluations and weekly sessions were registered and analyzed for two aspects: infant and parent behavior. The categories for the analysis of motor sensory development were in accord with the items proposed in AIMS and the training items were in accord with the OPI. The statistical treatment utilized the regression method to compare the evolution between the control and experimental groups. Analysis of parent participation in the intervention program was evaluated in three aspects: behaviors installed in the mediators, the performance of mediators as observers and the mediators opinion of the intervention program. The results demonstrated that both groups had significant improvement in all developmental areas analyzed and when compared to each other, the experimental group's evolution was superior to the control group. In relation to family participation in the program, the results verified that parents in the experimental group demonstrated a good level of involvement with behavior in installed in relation to training with the infant and both groups demonstrated satisfaction in participation in the study based on the evolution obtained by their children. Based on these results it can be stated that the participation of parents associated with the intervention program significantly benefited the sensory motor development of the infants in the present study. / A identificação precoce dos desvios do desenvolvimento em bebês pré-termo vem se destacando em vários estudos que enfatizam a prevenção de deficiências pela possibilidade de um melhor prognóstico por meio de serviços educacionais especializados ou outras medidas de reabilitação. Alem disso, os programas de intervenção vêm enfatizando a participação dos pais a fim de tornálos parte integrante e co-responsáveis do desenvolvimento de seus filhos. O objetivo desta pesquisa foi avaliar a eficácia de um programa de intervenção precoce com bebês pré-termo com e sem o treinamento dos pais. Participaram do estudo 08 bebês pré-termo, de ambos os sexos, com idade gestacional média de 32 semanas, idade cronológica média de 3 meses e 6 dias e suas respectivas famílias. O estudo foi desenvolvido no setor de Fisioterapia em Neuropediatria da UFSCar e aprovado pelo Comitê de Ética em Pesquisa da Universidade. O delineamento usado foi do tipo experimental e os participantes foram divididos aleatoriamente em dois grupos distintos: controle e experimental. O grupo controle era formado por quatro bebês que realizavam a fisioterapia e os pais não receberam orientação e treinamento para trabalharem os filhos em domicílio. O grupo experimental era composto de quatro bebês que receberam o tratamento de fisioterapia e cujos pais foram orientados e treinados para a continuação do programa em casa. O estudo teve um duração total de 4 meses e foram utilizados como instrumentos de medida do desenvolvimento dos bebês o Inventário Portage Operacionalizado (IPO) e a Alberta Infant Motor Scale (AIMS). Todos os dados das fichas de avaliação e filmagens das avaliações mensais e sessões semanais foram registrados e analisados em dois aspectos: comportamentos do bebê e comportamento dos pais. As categorias de análise do desenvolvimento sensório-motor foram de acordo com os itens propostos na AIMS e nos itens de treino do IPO. O tratamento estatístico utilizado foi o método de regressão para comparar a evolução obtida entre os grupos controle e experimental. A análise da participação dos pais no programa de intervenção foi avaliada em três aspectos: comportamentos instalados nos mediadores; desempenho dos mediadores enquanto observadores; opinião dos mediadores sobre o programa de intervenção. Os resultados demonstraram que os dois grupos de bebês tiveram evoluções significativas em todas as áreas do desenvolvimento analisadas e quando comparados os grupos verificou-se que o grupo experimental apresentou uma evolução superior à apresentada pelo grupo controle. Em relação à participação das famílias no programa de intervenção verificou-se que os pais do grupo experimental apresentam um bom nível de envolvimento, com instalação de comportamentos em relação aos treinos com a criança e os dois grupos demonstraram satisfação em participar da pesquisa com base na evolução obtida pelos filhos. Com base nestes resultados pode-se afirmar que a participação dos pais associada ao programa de intervenção aplicado beneficiou significativamente o desenvolvimento motor dos bebês do presente estudo.