NCube/papyrus huggingface dataset:
The Origin and Stimuli Implicated in the Expression of Nestin(+) Cardiac Myocyte-like Cells in the Ischemic Heart

Studies from our lab demonstrated that scar formation and healing was associated with the appearance of nestin(+) cardiac myocyte-like cells predominantly at the peri-infarct region. The focus of the present study was to identify the underlying mechanism(s) (e.g. hypoxia, neurohormones) implicated in their recruitment and their cellular origin. The presence of these cells was detected as early as 1-week post-myocardial infarction (MI) and persisted 9 months after complete coronary artery ligation. Furthermore, nestin(+) cardiac myocyte-like cells were also detected in the infarcted human heart. Hypoxia represents a predominant stimulus following MI, however the exposure of normal rats to a hypoxic environment failed to promote the re-appearance of nestin(+) cardiac myocyte-like cells. By contrast, the infusion of the non-selective  -adrenergic agonist isoproterenol (ISO) in the normal adult Sprague-Dawley rat increased nestin expression in the left ventricle and was associated with the reappearance of nestin(+) cardiac myocyte-like cells. However, the reappearance of nestin(+) cardiac myocyte-like cells may not represent a direct effect but was apparently secondary to cardiac myocyte necrosis mediated by isoproterenol. Lastly, we identified a subpopulation of nestin-immunoreactive cells in the normal rat heart that coexpressed cardiac progenitor cell markers Nkx-2.5 and GATA-4. This subpopulation of nestin/Nkx-2.5/GATA-4 cells may represent the progenitor pool that differentiates to a nestin(+) cardiac myocyte-like cell following an ischemic insult.  Key words: nestin, isoproterenol, cardiac myocyte, cardiac progenitor, necrosis

Keyphrases: Isoproterenol, Cellule Progenitrice, Necrose, Nestin, Isoproterenol, Cardiac Myocyte, Cardiac Progenitor, Necrosis
Plasticité présynaptique et gliale à long-terme en réponse à un changement chronique de l’activité synaptique,à la jonction neuromusculaire d’amphibien

Synaptic plasticity is a major property of the nervous system, believed to be at the basis of neuronal information processing.  This plasticity has been generally described with pre and postsynaptic adaptations.  Notably, presynaptic efficacy, referring to the probability of transmitter release associated with the quantal content of a synapse, can be increased or decreased according to the previous history of synapses.  Despite this characterization, the mechanisms implicated in the activity-dependent determination of synaptic efficacy remain unknown.  Moreover, synaptic plasticity has never been described in terms of glial adaptations, thus limiting our comprehension of neuronal information processing.  Nevertheless, the past decade has lead to a redefinition of glial cells functions. Relegated to a passive role of neuronal support in the past, glial cells are now known to be involved in the regulation of neurotransmission.  For instance, at the neuromuscular junction (NMJ), perisynaptic Schwann cells (PSCs) are believed to modulate synaptic efficacy and plasticity.  Such an active role requires, however, that PSCs adapt to the changing needs of NMJs.  Thus, synaptic plasticity must underlie glial plasticity.  At the NMJ, changes in synaptic activity result in several morphological and physiological adaptations.   Among others, chronic nerve stimulation was shown to decrease synaptic efficacy and short-term depression.  Conversely, chronic blockade of postsynaptic nicotinic receptors increases synaptic efficacy.  Given that PSCs can detect and respond to neurotransmission with a calcium elevation and that they react to environmental stimuli with morphological, physiological and gene expression adaptations, we propose that prolonged changes in synaptic efficacy, induced by chronic nerve stimulation or chronic blockade of nicotinic receptors, would lead to PSCs adaptations.  Thus, in this thesis, we studied, in parallel, long-term presynaptic and glial plasticity, in response to chronic changes in synaptic activity, at the amphibian NMJ.   Our results show presynaptic adaptations of synaptic efficacy, short-term plasticity, mitochondrial content and calcium signalling.  They also reveal several adaptations of PSCs, related to their sensitivity to neurotransmitters and their calcium responses properties.  These presynaptic and glial adaptations are discussed, in parallel, in terms of possible mechanisms and functions in the regulation of neurotransmission.  Our work also confirms the coincidence of presynaptic and glial plasticity and, therefore, raises the importance of glial adaptations for the maintenance of synaptic function.

Keyphrases: Mitochondries, Frequenine, Perisynaptic Schwann cell, Neuromuscular junction, Synaptic plasticity, Synaptic depression, Post-tetanic potentiation, Mitochondria, Frequenin, Chronic nerve stimulation, Chronique blockade of nicotinic receptors, Calcium imaging
Caractérisation électro-clinique des convulsions fébriles et risque d’épilepsie

The incidence of epilepsy in children with febrile seizures (FS) varies from 2 to 3%, but available clinical tools do not allow the identification of those children who will later develop epilepsy. Evidences have shown quantitative EEG abnormalities, more particularly revealed by intermittent photic stimulation (IPS), in patients with epilepsy. No studies have yet examined quantitative EEG parameters in children with FS. It is not known either whether they can be relevant to the evaluation of FSs prognosis. The objectives of this research program were to identify, first, clinical risk factors for developing epilepsy after FS and, second, to determine quantitative EEG markers that differentiate FS patients from normal controls and may aid to evaluate their prognosis. In order to meet our first objective, we reviewed the charts of 482 children with FS, aged 3 months to 6 years. Using survival statistics, we described risk factors for developing partial (prenatal antecedents, developmental delay, prolonged and focal FS) and generalized (family history of epilepsy, recurrent FS and FS after the age of 4 years) epilepsy after FS. In addition, we identified several distinct clinical phenotypes related to the prognosis of FS: (i) simple FS with a family history of FS, not related to a subsequent epilepsy, (ii) recurrent FS with a family history of epilepsy and an increased risk of generalised epilepsy and (iii) focal FS with a family history of epilepsy and an increased risk of partial epilepsy.  In order to meet our second objective, we analyzed the steady-state visual potentials (SSVEP) evoked by IPS (5, 7.5, 10 and 12.5 Hz) as a function of age. The high density EEG (128 channels) was recorded in 61 normal children between 6 months and 16 years of age and 8 adults. We showed different topographical development of low (5-15 Hz) and high (30-50 Hz) frequency SSVEP components phase alignment. Thus, low frequency phase alignment increased with age only over the frontal and occipital regions, whereas high frequency phase alignment increased over all cerebral regions.  Then, using the same methodology, we investigated whether children with FS show abnormalities of gamma frequency SSVEP components. We show an increase of both magnitude and phase alignment of the gamma frequency SSVEP components in 12 FS patients compared to 5 siblings of FS patients and 15 control children between 6 and 36 months of age. This study has identified distinct electro-clinical phenotypes that differentiate FS patients from the group of siblings and controls. Future studies should investigate whether detected abnormalities are associated with the clinical presentation of FS and their prognosis. This could help identify children with FSs who will later develop epilepsy and would eventually allow the institution of an early neuroprotective treatment.

Keyphrases: Phase, Oscillations, Risk factors, Epidemiology, Child, Electroencephalography, Steady-state visual evoked potentials, Quantitative EEG analysis, Phase, Oscillations, Gamma activity, Development
Le libre accès pour les bibliothèques de la santé : des ressources à découvrir

This talk is aimed at health information specialists and discusses the following aspects of Open Access: 1. The world of Open Access: definitions and statistics; 2. Using the resources; 3. Open Access publishing (CIHR and FRSQ policies on access to research outputs); 4. Roles and opportunities for health libraries.

Keyphrases: Open Access, health library, CIHR Policy on Access to Research Outputs, Open access Journals, Open access publishing, statistics, Open access repositories
Étude de la fonction ovarienne chez les souris déficientes des enzymes hyaluronidases

Female mammals are born with a large number of ovarian primordial follicles, though the vast majority of these never reach the preovulatory stage and undergo atresia, mainly through granulosa cell apoptosis. Our laboratory has established that mammalian hyaluronidases induce apoptosis of ovarian granulosa cells and that they are involved in follicular atresia but that their apoptotic effect is not due to their enzymatic activity. Our model suggests that mammalian hyaluronidases might have a role in follicles not destined to ovulate. The aim of this study was to evaluate the folliculogenesis and fertility of mice devoid of these enzymes. Our results showed that Hyal-3 KO mice have normal folliculogenesis, which could be explained by a compensatory effect of Hyal-1 since its expression is upregulated in these mice. In contrast, Hyal-1 KO mice had increased numbers of primordial, primary and secondary follicles, particularly in young mice, and lower levels of granulosa cell apoptosis. In order to investigate the effect of the three hyaluronidases, Hyal-1, -2 and -3, without a compensatory effect by one another, we decided to create a transgenic mouse deficient in all these three hyaluronidases but only in the gonads by using the Cre/loxP system. We successfully created a plasmid containing the Cre sequence under the control of Inhibin-α promoter, which conducts gene expression in somatic cells of the gonads. In conclusion, the present work demonstrates that Hyal-3 does not have any effect on ovarian function, but that deletion of Hyal-1 in mice promotes increased folliculogenesis and lowers granulosa cell apoptosis.

Keyphrases: Hyaluronidase, Hyaluronidase, Folliculogenesis, Follicular atresia, Hyal deficient mice, Apoptosis, Cre/loxP system
La transplantation d’hépatocytes chez le rat Long Evans Cinnamon, modèle animal de la maladie de Wilson

Wilson’s disease (WD) is a hereditary metabolic disease caused by a deficiency of copper-transporting ATP7B, resulting in copper accumulating to toxic levels in the liver.  Its manifestations range from acute or chronic hepatic insufficiency to fulminant liver failure. The mainstay of therapy is the use of chelating agents.  However selected patients may also require orthotopic liver transplantation (OTL), an invasive and complex procedure with life-long implications.  Hepatocyte transplantation  is an appealing alternative to OLT.  Its safety and efficacy  were evaluated in the animal model of WD, the Long Evans Cinnamon (LEC) rat.  Twelve LEC rats received an intrasplenic injection of 2,6 x 105 – 3,6 x 107 hepatocytes obtained from LE donor rats.  They were followed for 6 months before sacrifice.  They were then compared to a control group of twelve rats.  No difference was found when comparing their weights, biochemical parameters such as liver function tests and bilirubin, as well as their biliary and hepatic copper concentrations.  However, the ceruloplasmin oxydase activity was improved in the transplanted rats (49,6 ± 31,5 versus 8,9 ± 11,7).  After sacrifice, histologic evaluation and demonstration of atp7b mRNA in the recipient liver were performed.  There was evidence of histological improvement and atp7b mRNA was found in 58% of transplanted rats with an expression of 11,9% ± 13,6 when compared to a normal LE rat.  Evidence of successful engraftment of the transplanted cells was found in every transplanted rat using the technique of immunohistochemistry.  These encouraging results are in accordance with previous studies on hepatocyte transplantation in the LEC rat.  Its application to the human clinical setting is the next step, as it has already been tried in other metabolic liver diseases.

Keyphrases: Wilson, ATP7B, Hepatocyte transplantation, LEC rat, Metabolic disease
Estimation des longueurs de branche et artefact sur la datation moléculaire

Molecular phylogeny provides an additional tool complementary to paleontological and geological studies, allowing the reconstruction of phylogenetic relationships between species and the estimate of their divergence time. Researchers are mainly focusing on the topology of a phylogenetic tree; i.e. the relative connection between different nodes. Whereas, the branch lengths of this phylogeny are often considered as secondary, i.e. as additional parameters containing little information. However, the branch lengths are the primary information for molecular dating. Importantly, saturation, the presence of multiple substitutions at the same position, is an artifact that leads to an underestimation of the branch length. We are therefore interested in estimating the magnitude of this phenomenon and its impact on divergence time.  We chose to study the mammalian mitochondrial genome, which is available for many species and displays a high level of saturation. Furthermore, the phylogenetic relationships of mammalians are known, thus allowing us to fix the topology, thus eliminating one of the parameters influencing the branch lengths. We used two main approaches to improve the detection of multiple substitutions: (i) an increase in the number of species breaks the longest branches of the tree, (ii) more realistic models of sequence evolution. The results demonstrate that there is a very pronounced underestimation of branch lengths (up to a factor of 3). Furthermore, the use of a large number of species is the factor that influences most the detection of multiple substitutions, not the improvement of the model of sequence evolution. This suggests that even the most complex evolutionary models currently available, like the CAT+ Covarion model, which takes into account the heterogeneity of the substitution process between sites and the rates of evolution over time, are still far from taking the entire complexity of biological processes into account. Despite the important underestimation of branch lengths, the impact on dating appeared to be relatively limited, because the underestimation is more or less homothetic. This is obviously true for the complex evolutionary models. Since multiple substitutions are most effectively detected when breaking the long internal branches via the addition of species. This raises the problem of bias in the taxonomic sampling, due to the impact of extinction on the history of life on earth. Because this kind of bias leads to a non-homothetic underestimation, we consider it essential to improve models of sequence evolution and suggest that the protocol developed in this work will allow to evaluate their effectiveness towards saturation.

Keyphrases: Phylogeny, Molecular dating, Branch lengths, Evolutionary models
L'activation des mères seules prestataires d'aide sociale : quels effets sur leur santé et leur bien-être?

This research is about the impact of the active policy designed for social assistance recipients on lone mother’s health and well being. In Quebec, a social assistance recipient who has a child aged less than 5 receives a temporarily limited capacity allowance. When the child begins school, the lone mother is no longer considered to have limitations to work. Indeed, Emploi-Québec considers this time as the most suitable time to return to work. As part of this research, I analyzed what this moment of transition represented for lone mothers in terms of new employment relationships and possible employment strain. I have met 13 lone mothers who received social assistance within the past year. The data obtained via the interviews helped me meeting my research objectives, which were: 1) reconstruct the insertion trajectories of the lone mothers in the labour market, with emphasis on the moment of transition, and 2) understand the process by which these insertion trajectories have an impact on the health and well being of this population. I first found that the “social assistance relationship” had negative impact on the respondents’ health and well being. The causes for this are fundamentally the social assistance program’s standards that underlie the low level of allowances. Regarding the impact of the activation process itself on the health and well being of the lone mothers I met, I noted that the participation to active measures in community-based organizations specialized in employability programs had positive impact on them, especially on their well being. However, the activation process has also been recognized as having a negative impact on their health and well being because of the strain linked to Emploi-Québec’s demands related to the participation in active measures and to the lack of resources available to lone mothers participating to these measures.

Keyphrases: activation, emploi, activation, social policies, employment, lone mothers, social assistance, poverty, health, well being
La sécurité des xénogreffons : une normativité à bâtir

Xenotransplantation that is, the transplantation of non-human animal cells, tissues and organs into humans, is considered a solution to the organ shortage problem. However, this technology could be the source of new diseases; therefore, it is necessary to have measures aimed at assuring the health of animal donors as well as the quality and safety of the xenografts in order to minimize the risks of disease transmission from animal to human, called xenozoonosis. The subject of this master's thesis is to verify if the standards that exist in Canada and in Quebec are appropriate to assure the safety of the recipients and the population. In the first place, we have examined the standards that could apply to the surveillance and control of the health of animal donors. These standards that apply to known diseases do not meet the specificities of xenotransplantation. As for the xenografts, their qualification is problematic: drugs or medical devices? This possibility of a double status could affect the uniformity of the decisions relative to their quality and safety. We have also studied the Proposed Canadian Standard for Xenotransplantation. The latter may resolve the unsuitability of normative standards that exists in Canada. A comparison of such a Canadian standard with the WHO recommendations and the measures in place in the United States allows us to recommend on how to improve it. Our study reveals that a Canadian normative standard that focuses on the security of the xenografts is still to be implemented. An essential element to be considered in its development, is the need to establish a worldwide compatible and suitable control system.

Keyphrases: Law, Ethics, Norms, Quality control, Health of the animaIs, Public health, Safety, Organ transplantation, Xenotransplantation, Xenozoonosis
Convergence of corporate governance : comparative study in Canada and in China

This thesis aims to consider the debates in the field of corporate governance in the fact that there have been and will be dramatic changes in the structure of corporate activities, such as the nature of work and the organization of corporations, as well as the influences of reforms in the financial reforms. Moreover, the emergence of institutional investment in the financial markets, the process of globalization and the development of electronic commerce have the influences on the corporate governance both in Canada and in China. There is an immense magnitude of discussion on various aspects of corporate governance in the academic field. This thesis will focus on comparing two rather distinctive systems of corporate governance, with respect to three specific aspects of the corporate governance. Those are: the board of directors, the role of shareholders, the roles of banks and investors in the two countries, also the reforms in China. Moreover, the convergence of the two corporate governance systems is introduced.

Keyphrases: Convergence, Canada, Corporate governance, Board of directors, Shareholder, Reform, China
Une analyse de la sanction économique en droit international

The fundamental criticism addressed to internationallaw denounces the weaknesses of its sanctions mechanisms. For this reason, severallegal thinkers conc1uded to the inexistence of international law. The present text studies the rhetoric behind this statement and examines its validity. To do so, we analyze in the first place the relationship between sanction and law through the positivist framework of the XIXth Century. We examine in turn the so-called fundamental elements of sanction. We compare these elements with different non-Iegal orders so that we can ultimately reject the positivist theory according to which coercion and centralization ofpower are the fundamental elements of sanction. Chapter II examines the United Nations Security Council framework for adopting economic sanctions. This step allows us to underline the main sources ofweaknesses and limitations of internationallaw. In this respect we observe that the lack of international cooperation is the major weakness of internationallaw. Furthermore, an analysis of the relevant dispositions of the United Nations Charter shows that the veto right and the principle of international sovereignty are two elements that hamper international cooperation. We then study the objectives behind the adoption of sanctions as well as their effectiveness. Finally, we study general embargoes as well as arms embargos. This inquiry allows us to focus on the effects of economic sanctions on both civilians and third States. It also helps us understand the problems with regard to the administration of a sanction, as well as the ways to bypass the prohibitions.

Keyphrases: Sanction, Arms embargo, International cooperation, International law, National sovereignty, Positivism, Right Veto, Security Council, United Nations
L'utilisation des cellules souches embryonnaires à des fins thérapeutiques

The embryonic stem cells discovery and the immense therapeutic potential glven to them has created big hopes in the world of today. The appearance of new revolutionary therapies to treat sorne of the most serious known diseases are now conceivable. However, the treatment of life to its earliest stage is questionned. The legal status recognized to the foetus and the embryo has, in fact, a direct effect to the research area and industry as weil as to its therapeutic use. Therefore, we have examined and studied the CUITent canadian law with respect to the legal status of the foetus and embryo. Following this study, we have noticed the uncertainty that prevails in Canada concerning the said legal status. Afierwards, we have examined ail the different canadian norms and regulations already established regarding the use of embryonic stem cells for therapeutic ends. We also did the comparaison between those norms and regulations so as to see their differences and similarities. It appears from our analysis that ail the canadian litterature generally treat the subject in the same way and that there have been few changes from 1993 up until now with respect to the forbidden researchs activities in Canada. We also have analysed the foreign law standards and regulations in United States and Great Britain concerning those forbidden researchs activities. We did the exercise of comparing the state of the law in these three countries with different parameters. It emerges from that that Great Britain is the most liberal country, United States being the most conservative and Canada being in between them.

Keyphrases: Canada, Embryon, Foetus, Embryo, Embryonic stem cells, Great Britain, Legal status, Norms, Regulations, Stem cells, Therapeutic ends, United States