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Nicolas Bertrand

Publications and source records attributed to Nicolas Bertrand.

5 recordsLinked to original sources
PubMed2006

Sonic hedgehog signaling in forebrain development and its interactions with pathways that modify its effects.

During the development of the nervous system and other organs in the embryo, a limited set of master signaling pathways are used repeatedly for induction, patterning and growth. Among these, the Sonic hedgehog (Shh) pathway is crucial for the development of many structures in the brain. How the context-specific interplay between these various signaling pathways produces distinct temporal and spatial outcomes is not clear. Resolving this problem is a major goal in the study of cell and organ development. Here, we focus on signaling events during dorso-ventral patterning of the embryonic forebrain in vertebrates. In particular, we discuss the role of the Shh pathway in this process and on its interactions with the FGF, retinoic acid and Nodal pathways and other information cascades that modify its effects.

Animals↗
PubMed2006

[Linguistic validation of the "Brief Index of Sexual Functioning for Women"].

UNLABELLED: Application to the study of sexuality in a population of 93 French women. OBJECTIVES: This study was designed to linguistically validate the French version of the BISF-W (Brief Index of Sexual Functioning for Women) which provides a quantitative and qualitative assessment of female sexuality according to 7 dimensions. This version was then used to study the impact of recognized factors of sexual dysfunction on a control population. MATERIAL AND METHOD: The BISF-W a self-administered quality of life questionnaire developed by Rosen, was translated and linguistically validated. This questionnaire comprises 22 questions in 7 dimensions investigating all aspects of female sexuality: D1 (desire), D2 (arousal), D3 (frequency of sexual activity), D4 (receptiveness), 05 (pleasure, orgasm), D6 (relational satisfaction), D7 (problems affecting sexuality), Composite Score (CS) D1+D2+D3+D4+D5+D6+07. The French version was administered to a study population of 93 women: 49 derived from gynaecology or urology departments and 44 derived from the general population. We calculated and compared the scores of the various dimensions of the BISF-W according to factors able to modify sexuality, such as menopause, age or parity. RESULTS: The results of our study show an alteration of the various dimensions of sexuality in elderly patients (D2, D5, D6, CS; p<0.05) or postmenopausal patients (D2, D5, D6, CS, p<0.05) and in multiparous women. CONCLUSION: The French version of the BISF-W gives results in line with the literature and demonstrates changes of sexuality as a function of the above mentioned variables.

Adult↗
PubMed2004

Specific regulation of cyclins D1 and D2 by FGF and Shh signaling coordinates cell cycle progression, patterning, and differentiation during early steps of spinal cord development.

In the vertebrate embryo, spinal cord elongation requires FGF signaling that promotes the continuous development of the posterior nervous system by maintaining a stem zone of proliferating neural progenitors. Those escaping the caudal neural stem zone, which is expressed to Shh signal, initiate ventral patterning in the neural groove before starting neuronal differentiation in the neural tube. Here we investigated the integration of D-type cyclins, known to govern cell cycle progression under the control of extracellular signals, in the program of spinal cord maturation. In chicken embryo, we find that cyclin D2 is preferentially expressed in the posterior neural plate, whereas cyclin D1 appears in the neural groove. We demonstrated by loss- and gain-of-function experiments that FGF signaling maintains cyclin D2 in the immature caudal neural epithelium, while Shh activates cyclin D1 in the neural groove. Moreover, forced maintenance of cyclin D1 or D2 in the neural tube favors proliferation at the expense of neuronal differentiation. These results contribute to our understanding of how the cell cycle control can be linked to the patterning programs to influence the balance between proliferation and neuronal differentiation in discrete progenitors domains.

Animals↗
PubMed2002

Proneural genes and the specification of neural cell types.

Certain morphological, physiological and molecular characteristics are shared by all neurons. However, despite these similarities, neurons constitute the most diverse cell population of any organism. Recently, considerable attention has been focused on identifying the molecular mechanisms that underlie this cellular diversity. Parallel studies in Drosophila and vertebrates have revealed that proneural genes are key regulators of neurogenesis, coordinating the acquisition of a generic neuronal fate and of specific subtype identities that are appropriate for the location and time of neuronal generation. These studies reveal that, in spite of differences between invertebrate and vertebrate neural lineages, Drosophila and vertebrate proneural genes have remarkably similar roles.

Animals↗