NCube/papyrus huggingface dataset:
L’effet des différents facteurs de croissance sur la viabilité et la prolifération des ostéoblastes scoliotiques

Abstract: The Adolescent Idiopathic Scoliosis (AIS) is a debilitating condition and as a result often produces significant pain, impaired daily functioning and a deterioration of the quality of life. For patients who do not respond to conservative treatment, spinal fusion using bone grafts has become a treatment of choice to stabilize the spine.  The more accurate knowledge of the factors involved in osteogenesis and the bone formation can shorten the healing process and reintegrate patients into their daily activities in a shorter period of time. Platelets can play an important role in the first stage of the healing of fractures and they are a source of several autologous growth factors that support the proliferation and differentiation of osteoblasts in vivo and in vitro.   A wide variety of techniques and approaches have been investigated for performing spinal fusion, yet surgeons continue to investigate alternative methods with the goal of improving surgical outcome and minimizing morbidity. We can use these methods to:  1.Reduce the relatively long time needed for healing fractures   2. Patients with prosthesis could benefit of a shorter convalescent time 3. Several congenital diseases could be easier to correct and 4. We could stimulate the vertebral fusion 5. Develop new therapeutic techniques, including that of the processes regulating bone remodelling and regeneration of bone tissue. In the present study, we tried to find whether the insulin growth factor (IGF) and the vascular endothelial growth factor (VEGF) have an influence on the scoliotic osteoblasts in vitro cell cultures and we compared the results with those obtained in the same condition but by stimulating osteoblasts with melatonin. This preliminary study was performed on osteoblasts cultured from four patients affected by Adolescent Idiopathic Scoliosis (AIS) and four controls. In all cases of AIS, bone specimens were obtained from the vertebral body or spinous process (in accordance with the surgical procedure performed). Our results show that IGFs as well as VEGF have an inhibitive effect on the proliferation of scoliotic and non-scoliotic cells and the effect is proportional with the growth factor concentration. In general osteoblasts cultured from scoliotic patients have an in vitro osteogenesis quicker than the subject without scoliosis. Moreover, it appears that melatonin plays a physiological role in the differentiation of scoliotic osteoblasts and it appears to help differentiate earlier than in the untreated group. We found that the expression of IGF 1 and IGF 1R in scoliotic osteoblasts was impaired in the presence of melatonin. In conclusion, VEGF A and IGF both can influence the cell differentiation and proliferation of human scoliotic osteoblasts in primary cell culture.

Keyphrases: IGF, VEGF, Adolescent idiopathic scoliosis, growth factors, osteoblasts, IGF, VEGF, melatonin
Caractérisation structurale de la molécule HLA-DO

Classical MHC class II molecules present antigenic peptides to CD4+ T cells.  This presentation is regulated by two non-classical molecules: HLA-DM catalyzes CLIP release and peptide loading and HLA-DO mediates the DM activity.  An insufficient expression in insect cells did not allow DO crystal production experiments, probably because of its conformation, rendering DO unstable and unable to leave the endoplasmic reticulum (ER).  DM corrects the conformation of DO and allows its egress from the ER. Also, because of its unique disulfide bonds, DM has a stable conformation and can egress from the ER without binding another molecule.  We tried to correct the conformation of DO by introducing cysteines to create disulfide bonds homologous to those of DM.  However, its conformation was not corrected.  Also, we increased DO expression by inserting a partial Kozak sequence.  We also studied the effect of DM on DO expression.  DM favoured DO expression, probably by reducing its degradation.  Each chain of the DMαβ dimer plays a role in the oxidation of its partner chain.  The non-optimal conformation of DO might result from an incapacity of its α and β chains to direct each other’s oxidation; DM would correct this problem.  Our Western blot analysis showed, however, that DM does not modify the oxidation state of DOα and DOβ.  Finally, we studied the DO-DM interaction.  The DOαE41 amino acid is involved in this interaction, as some of the α80 to α84 might be.  We mutated amino acids in this region of DO.  Tested amino acids did not seem involved in DO-DM binding.  The tridimensional structure of DO and the characterization of its oxidative state and its DM binding will allow a better understanding of its function.

Keyphrases: Conformation, CMH II, HLA-DM, HLA-DO, Structure, MHC II, Antigen presentation
Étude de l’activité de Staufen1 dans la régulation traductionnelle de certains ARNm

Transport and local translation of RNA are found in several organisms and are required for multiple phenomena such as memory, asymmetric cell division and establishment of the axis during development. Staufen, a double-stranded RNA binding protein, was first identified in Drosophila melanogaster. In the fruitfly, it was shown that Staufen is required for the proper localization of the bicoid and oskar transcripts to the anterior and posterior ends of the oocyte, respectively. It was also found that Staufen is important for the translational derepression of oskar once it is adequately localized. In mammals, Stau1 is a ubiquitous protein found in granules in the dendrites of neurons. Also, Stau1 can bind the ribosome in a RNA-independent manner and cofractionates with both ribosomal subunits in a sucrose gradient. The implication of Stau1 in a mechanism allowing translational derepression of certain RNAs in mammals was therefore an interesting path to explore. Accordingly, we decided to verify if mammalian Stau1 had the capacity to stimulate the translation of cellular RNAs through a regulated mechanism. When this thesis was initiated, no cellular RNA target of Stau1 had been identified in mammals. Therefore, double-stranded RNA structures were used to repress the translation of a reporter mRNA. With this model, we showed that Stau1 can stimulate the translation of a transcript when it is bound to its 5’ UTR. With the use of DNA microarrays, we identified cellular mRNAs which distribution in heavy polysomes was altered by Stau1. When Stau1 is overexpressed, this group of mRNAs is enriched heavy polysomes, suggesting a translational stimulation of this population by Stau1. To identify a regulatory mechanism that could influence Stau1’s translational activity, we studied the self-association capacity of this protein. We showed that Stau1, like several double-stranded RNA binding proteins, can self-associate in a RNA-independent manner. We have identified the determinants required for this interaction that as the potential to be important for the regulation of the cellular activities of Stau1. The results presented in this thesis suggest that Stau1 can stimulate the translation of a specific subset of mRNAs in the cell, letting us look at Stau1’s implication in different processes from a new point of view.

Keyphrases: Stau1, Messenger RNA, Translation, Double-stranded RNA, Self-Association, Double-stranded RNA binding domain
Caractérisation du co-transporteur Na+/myo-inositol SMIT2 dans les membranes en bordure en brosse de rein de lapin et d’intestin de rat

Myo-inositol (MI) is an organic solute involved in various aspects of cell physiology, including cell signaling. It is also known as a compatible osmolyte. Three secondary active MI cotransporters have been identified; two are Na+- coupled (SMIT1 and SMIT2) and one is H+-coupled (HMIT). The main aim of this study was to characterize MI uptake throught SMIT2 as expressed in epithelial cells and in Xenopus laevis oocytes. In order to achieve the characterization of this transport system, we used purified brush border membrane vesicles (BBMv) isolated from rabbit kidney and rat intestine. We first performed a quantification of mRNA levels in rabbit kidney using real time PCR for both SMIT1 and SMIT2. We found that SMIT1 is mainly expressed in the renal medulla while SMIT2 is mainly localized in the renal cortex. This result was confirmed on Western blots using an antibody raised against SMIT2. Through inhibition studies using selective substrates for SMIT1 (inhibited by L-fucose) and SMIT2 (inhibited by D-chiroinositol), we showed that SMIT2 seems to be responsible for all the apical transport of MI into the proximal convoluted tubule with a Km of 57 ± 14 µM. By transport studies we established that rabbit intestine seems to lack apical transport of MI while rat intestine has a very active uptake of this molecule. qRT-PCR quantification confirmed the absence of MI transporters in rabbit intestine. As for kidney, SMIT2 seems to be the only transporter responsible for apical MI uptake in enterocytes with a Km of 150 ± 40 µM. Functional analysis of rat SMIT2 activity, via electrophysiological studies in Xenopus oocytes, demonstrated similarities to the activities of SMIT2 from rat intestine and rabbit kidney. SMIT2 displays high affinities for MI (270 ± 19 µM), DCI (310 ± 60 µM) and no affinity for L-fucose. SMIT2 is very sensitive to phlorizin (Pz; 16 ± 7 µM). Although these functional characteristics essentially confirmed those found in rat intestine, a iv discrepancy exists between the two systems studied. Indeed, the affinity constant for glucose was approximately 40-fold lower in vesicles than in oocytes. We also tested the ability of SGLT1 and GLUT5, other sugar transport systems present in enterocytes apical membranes, to perform MI uptake. Because the inhibition of these transporters did not alter radiolabeled MI uptake, we concluded that they had no significant contribution to MI transport in rat intestine. Finally, the basolateral efflux of MI was not mediated by GLUT2 because when expressed in oocytes, this transporter was not able to transport MI.

Keyphrases: Smit2, Myo-inositol, Smit1, Glucose, transport membranaire, Smit2, Myo-inositol, Phlorizin, Smit1, Glucose, Brush-border membrane vesicles, Oocytes, Membrane transport
Associations between Exposure to Socio-Cultural Influences in Proximal Environments and Weight Concerns among Urban-Dwelling Women

Abstract Weight and eating-related disorders and behaviours are common among adolescent girls and young women in Western societies, where thin bodies are highly valued.  The goal of this study was to examine whether or not more frequent exposure to places promoting thinness is associated with greater weight concerns among women.   This study was part of a larger investigation entitled ¨Social, cultural, and economic disparities and disordered eating: Understanding the contribution of neighbourhood and individual level factors¨ (Gauvin, Steiger, & Brodeur, 2009). A sample of 1288 women aged 20 to 40 years and living in Montreal for at least 12 months responded to a telephone survey. Logistic regression analyses were performed comparing women in the highest quintile of weight concerns to women in other quintiles on frequentations of thin-promoting places 15 days or more. Further, a sensitivity analysis was performed to verify whether or not an association exists between high weight concerns and different levels of exposure to places promoting socio-cultural standards for thinness. A series of confounding variables were statistically controlled.  Results showed that exposure to places promoting socio-cultural standards for thinness at least 15 days per month was significantly associated with greater weight concerns among women despite controlling for confounding variables.  Further, going to places promoting thinness between at least 15 through 20 days/month was also associated greater weight concerns among women. Public health interventions could aim at reducing societal pressures to thinness.

Keyphrases: Weight perceptions, Obesity, Eating disorders, Thinness, Mass media, Social environments, Population-based study, Women
Modulation différentielle par la privation de sommeil des processus attentionnels frontaux et pariétaux: une étude de potentiels évoqués cognitifs

The objective of the present study was to assess the differential effects of sleep deprivation (SD) on cognitive functions relying on distinct cerebral networks, involved in the fronto-parietal attentional network, during a relatively simple and short cognitive task. Multi-sites recording event-related-potentials (ERP) were used in order to evaluate the effect of SD on rapid cognitive activity and its topographical correlates. The morning following a night of total SD and a night of sleep, 20 participants were administered a 3-stimuli visual oddball paradigm. Amplitudes and latencies of the P200 and N200 ERP components were analyzed as frontal indexes, whereas P300 was analyzed as a mixed frontal and parietal component. Following TSD, a non specific increase in P200 amplitude for the left hemisphere, as well as a loss of lateralisation in response to target stimuli, were observed. Contrarily, P300 amplitude was predominantly reduced in the parietal region in response to target stimuli. Moreover, N200 and P300 latencies were delayed non specific to the type of stimuli and performance (reaction time and accuracy) was altered. These results confirm the deleterious effect of a moderate duration SD on attention processes that can be objectified by means of behavioural and electrophysiological measures. Each stages of information processing was altered by SD, as shown by its effect on P2, N2 and P3 components. Moreover, SD affected differently components caracterized by a predominant frontal or parietal distribution.

Keyphrases: Attention, P200, N200, P300, Sleep deprivation, Cognitive functions, Information processing, Frontal lobes, Parietal lobes
Rapport à la nature et stratégies intégrées de conservation et développement : le cas de São Tomé et Principe

Since the beginning of the 1990s, Integrated Conservation and Development Projects have offered a functional model of sustainable development for specific sites within the perspective of particular projects. Their goal has been to integrate biological aspects of conservation to the social and economic aspects of development. Protected areas represent a particular vision of the relationship between man and nature, appeared in the American context with the creation of the first national parks. Currently, the wish to involve the population in the creation of protected areas faces the challenge of reconciling the management of these spaces with the local practices, needs and interests. Obô Natural Park, which occupies 30% of the territory of Sao Tome and Principe, follows the difficult process of integrating both local uses and representations of nature to the global objectives of conservationist policies while considering the touristic and economic interests of local and foreign investors. Social representations of nature, understood as a form of practical knowledge, determine the vision of the world and the relationship that a particular social group may have with its territory. Thus, based on this system, each community has its own mechanisms of environmental adaptation. In the case of the Saotomean communities, nature presents a strong spiritual (associated with beliefs, rituals and traditional medical practices) and utilitarian character (nature provides, through farming, collecting or hunting, all you need to live). The aim of this thesis is to understand the synergies between endogenous knowledge and management of biodiversity to adapt the land management process to the reality of the people who live in the particular territory of Sao Tome and Principe.

Keyphrases: Integrated conservation and development projects, Traditional ecological knowledge, Social representations, Biological diversity, São Tomé and Principe
Associations between area-level unemployment, body mass index, and risk factors for cardiovascular disease in an urban area

INTRODUCTION: Little is known about whether area-level unemployment is independently associated with individual-level Cardiovascular Disease (CVD) in an urban setting.  Furthermore, it is unclear whether this relationship differs by sex. This thesis examined the direction and magnitude of the association between area-level unemployment (ALU) and Body Mass Index (BMI) and a marker for CVD risk, and whether this association differs by sex. METHODS: A sample of 342 individuals from the Montreal Neighbourhood Survey of Lifestyle and Health (MNSLH) self-reported behavioural and socioeconomic information. A registered nurse collected biochemical and anthropometric data. ALU was operationalised within a 250 m radius buffer centered on individual residence using a Geographic Information System (GIS). Generalized Estimating Equations were used to determine if body mass index (BMI), and a cumulative score for total cardiometabolic risk (TCR) representing elevated values for total cholesterol, triglycerides, high-density lipoprotein cholesterol, and glycosylated hemoglobin, were associated with ALU. RESULTS: After adjustment for age, gender, smoking status, behavioural, and socioeconomic covariates, living in an area in the upper ALU quartiles was associated with an elevated BMI [Q4 beta = 2.1 kg/m2 (95% CI: 1.02-3.20)] and greater TCR [Q4 RR = 1.82 (95 % CI: 1.35-2.44); Q3 RR = 1.66 (95% CI: 1.33-2.06)] relative to the 1st quartile. Sex-by-ALU interaction revealed a 1.99 kg/m2 (95% CI: 0.00-4.01) difference in BMI and 1.39-fold (95% CI: 1.06-1.81) greater TCR Score for women compared to men. CONCLUSIONS: Area-level unemployment is associated with greater CVD risk in men and women but associations are stronger among women.

Keyphrases: Body Mass Index, Cardiometabolic Risk, Area-Level Unemployment, Social Context
Les mécanismes synaptiques et intrinsèques qui sous-tendent l’activité des cellules
réticulospinales (RS) en réponse à une stimulation sensorielle de type cutané chez la lamproie

In various animal species, sensory information can initiate locomotion. This relies on the integration of sensory inputs by the central nervous system. In lampreys, the spinal locomotor networks are activated and controlled by the reticulospinal cells (RS) which constitute the main descending system. In turn, RS cells receive information coming from various synaptic inputs such as the sensory afferents. Once activated by a brief cutaneous stimulation of sufficient strength, RS cells display sustained depolarizations of various durations that rely on calcium-dependant intrinsic properties and lead to the onset of escape swimming. During the course of this Ph.D, we aimed at determining whether synaptic inputs can modulate the duration of the sustained depolarizations and if the different populations of RS cells share the same integrative properties, possibly involving the internal calcium stores. First, our results show for the first time that excitatory glutamatergic inputs, including ascending spinal feedback, contribute to prolong the sustained depolarizations for long periods of time. Cutaneous inputs do not contribute to maintain the sustained depolarizations and inhibitory glycinergic and GABAergic inputs are not sufficient to stop them. Second, we show that in response to cutaneous stimulation, the RS located in the four reticular nuclei display a similar activation pattern and can all produce sustained depolarizations which do not depend on internal calcium release to be maintained. Finally, the results obtained during this Ph.D allowed us to better understand the cellular mechanisms by which the RS cells integrate and transform a brief sensory information into a sustained response associated with a motor command.

Keyphrases: locomotion, glutamate, CNQX, AP-5, glycine, strychnine, Sensorimotor integration, locomotion, reticulospinal cells, sensory relay cells, brainstem, cutaneous stimulation, trigeminal nerve, sustained depolarization, plateau potential, glutamate, CNQX, AP-5, glycine, strychnine, calcium imaging, lamprey
Imagerie par résonance magnétique spectroscopique et exploration neurochimique de régions cérébrales d'individus atteints d'un trouble léger de la cognition

Background: Mild cognitive impairment (MCI) characterizes individuals who present some cognitive impairment without criteria for dementia. Known as a highly plausible transitional stage between normal aging and Alzheimer’s disease (AD), the majority of individuals with MCI will eventually evolve to AD. Objective: The general aim of this multiple-cases study is to explore the contribution of magnetic resonance spectroscopy (MRS) to the neurochemical identification individuals with MCI in the process of evolving toward an AD. Methodology: Eight individuals were compared to eight age and education matched-controls. For each participant, MRS measures for XX neurometabolites were  taken from the left prefrontal and left posterior cingulate gyrus. Results: Among all the MCI participants, one of them converted to AD during the time of the study. The spectral analysis of this participant showed higher glutamate/glutamine ratios in both regions. Although a reduction of Naa/Cr is often/generally observed among the MCI population moving/headed toward dementia, the obtained/experimental results show/demonstrate nothing in this sense. Discussion/Conclusion: The role of glutamate in pathological processes is not well-known. These results suggest the probable existence of excitotoxicity mechanisms in MCI subjects who will convert to AD, a mechanism that could express the presence of some compensatory processes. While reporting the challenge of MRS measures in this population, this study provide indications of its potential for the early detection of AD in a MCI population.

Keyphrases: Mild cognitive impairment, Alzheimer's disease, Magnetic resonance spectroscopy, glutamate, glutamate
Impact de l’évolution des formes de croissance urbaine sur l’identité de la ville et de ses citoyens

The evolution of urbanization in the world motivated us to develop our research around this raging growth of cities and their resulting multitudes of urban forms. The object of this work is to analyze these spatial forms of growth and their impact on the city’s identity. The objective is to demonstrate in which measure they favour the proliferation of new identities in the suburb region of the city. Our research then focuses on a socio-spatial study of the capital of Tunisia. Tunis, this enlarging metropolis, occupies a strategically positioned location in the Mediterranean and plays an important role in European-African exchanges. The pertinence of the study of the evolution of the urban domain of Tunis results from the fact that this city experienced different types of growth. The variety of modes of development of the urban area makes Tunis a pertinent example which is worth being studied, especially since the space includes planned, spontaneous, historical suburbs, and many others which result from the informality linked from the heritage up to the construction of a plural urban identity. This work will thus include a spatial study of the evolution of the urban area of Tunis, based principally on maps and satellite pictures, complemented with a social analysis based on an in situ investigation, accomplished with the inhabitants of the suburbs with the intention of making a census of their degree of attachment to the space as well as their relationship with the downtown area. Our research allowed us to conclude that the inhabitants of the suburbs end up identifying themselves with new forms of growth and develop over the years a sense of belonging and attachment to their district. This contributes to the numerous proliferation of identity in the city.

Keyphrases: Tunis, Tunisia, extension, Forms of urban growth, sprawls, space development, identity, urban space expansion, suburban urban spreading, periphery, suburbs, suburban urban spreading