Pascale Garnier

Presence of norepinephrine and other biogenic amines in stonefish venom

Although fish venoms exert a cardiovascular effect, the presence of adrenergic substances was not previously demonstrated. Chromatographic analysis with electrochemical detection showed the presence of substances co-migrating with norepinephrine, dopamine and tryptophan. Serotonin, which was thought to be implicated in the intense pain following fish envenomation, was not detected. Norepinephrine was identified as a component of the stonefish Synanceia verrucosa venom by gas chromatography-mass spectrometry.

Does crude venom of the stonefish (Synanceia verrucosa) activate β-adrenoceptors in the frog heart muscle?

Venom isolated from the stonefish Synanceia verrucosa was assayed in concentrations of 0.07 and 5.7 micrograms/ml on frog atrial fibres and myocytes. Venom, less than 2.9 micrograms/ml, dose-dependently increased the amplitude and the duration of the stimulated peak tension, lengthened the time constant of the relaxation phase and shortened the duration of the action potential (AP). The concentration of venom 5.7 micrograms/ml decreased the amplitude of the peak tension, induced a contracture, reduced the amplitude of the plateau and shortened its duration as well as the repolarizing phase of the AP. The positive inotropic effect induced by the venom (2.9 micrograms/ml) on the contraction was inhibited dose-dependently by propranolol but was unchanged by the alpha-adrenergic antagonists urapidil and yohimbine, the adenyl cyclase activity remaining sensitive to forskolin. Venom, adrenalin and propranolol competed for a common site. Venom (2.9 micrograms/ml) increased both the Ca and the delayed outward K currents of enzymatically isolated atrial myocytes. The data suggest that the venom activates adrenoceptors, essentially beta-adrenoceptors.

Cardiotoxicity of verrucotoxin, a protein isolated from the venom of Synanceia verrucosa

Freshly purified but unstable verrucotoxin (VTX) and a more stable proteic complex of the toxin (p-VTX) were isolated from the venom of the stonefish Synanceia verrucosa and applied to frog atrial fibres. VTX and p-VTX decreased the amplitude and the duration of the stimulated peak tension and accelerated the relaxation phase of the contraction. The negative inotropic effect of p-VTX decreased with increasing the external Ca concentration ([Ca]o) in the Ringer solution. The negative chronotropic effect induced by p-VTX was insensitive to change in [Ca]o. It is reversed by glibenclamide. p-VTX shortened the duration of the plateau and the repolarizing phase of the action potential. Glibenclamide but not tetraethylammonium reversed the p-VTX-induced shortening of the AP repolarizing phase. The data suggest that the toxin isolated from the venom of S. verrucosa inhibits Ca channels and might activate ATP-sensitive potassium channels in frog atrial heart muscle.

The scholarisation of the French école maternelle: institutional transformations since the 1970s

The transformations that have taken place in the French école maternelle (nursery school) over the last 30 years may be characterised by a dual dynamic, internal and external, of scholarisation. Firstly, the analysis of its changing position with regard to primary school and within early childhood education and care shows a relative erasure of its specific nature and an increased dependency with regard to compulsory education. Secondly, an examination of the changes of its institutional curriculum and of the development of knowledge on school learning shows a growing focus on the mastering of language as it relates to the issues of educational success. This question of the influence of the école maternelle on childrens future school career also contributes to its definition as part of the first cycle of formal education. International comparisons of pre-primary education serve to underline this process of scholarisation and also the continued diversity of social functions performed by the école maternelle.

Children of Two to Three Years of Age in France: Early Childhood Settings and Age Divisions.

ABSTRACT In a French early childhood care and education system that is strongly divided by age and institution, the current research studies the collective life of children at the pivotal age of two to three years of age in four different early childhood settings: 1) a group of ‘grands’ (nursery) in a crèche (daycare centre), 2) a jardin maternel, 3) a classe passerelle and 4) a group including ‘tout-petits’ in an école maternelle (nursery school). Our methods combine the observation of children and the point of view of professionals, obtained using visual aids (photos and videos). We analyse successively the institutional organisation of ages, material culture and professional practices. Depending on the ways in which their age is defined by these settings, we show how these settings create different experiences for children, which make them ‘petit’ (at the école maternelle) or ‘grand’ (at the crèche). The interest of the jardin maternel and the classe passerelle is to show intermediate ways of framing the age of children two to three years old.

Objects for a ''healthy lifestyle'': children's material culture and physical activities

Purpose – The aim of the research is to emphasise the role of material culture, and especially the role of objects related to physical activities, in childrens socialization. It involves childrens bodies but also symbolic meanings and values which introduce children to the universe of sports consumption. Design/methodology/approach – The research is grounded on the construction of a system of objects related to childrens physical activities in France. The production of a corpus of objects involves a methodological circle where the choice of the objects goes together with a reflexive analysis about the operations of categorization of objects. The analysis of objects require both technological and semiotical approaches. Findings – In the context of globalization and commodification of childhood, but also of the globalization and mediatization of sports, the research shows that objects for childrens physical activities are inscribed in a double transformation: sportification of childrens games and chil...

Between Young Children and Adults: Practical Logic in Families’ Lives

Bourdieu devotes little attention to childhood in his empirical Studies, and inscribes it in a theoretical conception of socialisation.1 It seems that for him, the younger the child, the more strongly the structure of the social world is internalised, shaping the future social trajectory of the adult (Bourdieu 1977). This is evident in Distinction (1984), where Bourdieu highlights the importance of early childhood in the constitution of dispositions in relation to the position of the family in the social space. I would like to show that this conception of socialisation can be developed, through considering my empirical work concerning family practices in the field of early childhood education and using Bourdieu’s theory of practice. His large and consistent theoretical concern contrasts a practical logic engaged in by individuals acting in the midst of a situation with a theoretical logic that considers social practices from a distance as objects of thought. Articulating the empirical research study and the theoretical thinking is a necessity in Bourdieu’s idea of sociological research. In contrast to the division of labour, which is also a division of power, between ‘theoricism’ and ‘methodologism’, between the ‘great theorists’ who are not concerned about facts and avoid fieldwork, and the empiricists who lean toward the illusion that the facts speak by and for themselves, Bourdieu argues that research must be at the same time empirically and theoretically grounded, including an explanation of the philosophical anthropology that it involves.

OS OBJETOS ESPORTIVOS NA CULTURA INFANTIL: DIMENSÕES MATERIAIS E REPRESENTAÇÕES

Sports objects intended for children are part of children’s material culture. They put into play the child’s body with its actual physical, psychological, intellectual and social characteristics, and representations on the child at the time of the design and production of objects most suitable to each age. The aim of this article was to conduct, through qualitative research, an assessment of sports objects, considering their materiality and influence on children’s bodies, and to unveil ways to signify childhood and sports.

Transitions dans la petite enfance

In the changing political context of early learning and childcare in Scotland it is important to gather knowledge in order to understand the work of childminders and to make it more visible. The small scale scoping study presented here seeks to explore the role played, in Scotland, by childminders as they welcome and care for young children. In Scotland there are currently 6,102 people registered as childminders to provide day care in their own homes: they provide for 34,600 children (Care Inspectorate, 2015). Many of these childminders (about 80%) are members of the Scottish Childminding Association (SCMA). Their work is equivalent to that of day-carers and home-based carers in other countries. Typically, the children who benefit from their services have working parents who often choose this form of home-based care as the next-best choice to having their children at home.

Petite enfance et scolarisation

Ce dossier presente des travaux recents, emanant de champs disciplinaires differents, concernant la petite enfance et la prescolarisation. S’interrogeant sur les evolutions de l’ecole maternelle et de son positionnement par rapport a l’ecole elementaire et aux structures non scolaires d’accueil et d’education des jeunes enfants, Pascale Garnier fait le constat d’une emprise croissante des orientations proprement scolaires, c’est-a-dire liees a l’ecole elementaire de l’ecole maternelle. Christophe Joigneaux analyse quant a lui, les processus de differenciation et de production d’inegalites des l’ecole maternelle, au sens ou ces processus apparaissent a ce niveau de la scolarite dans des domaines et des pratiques relevant de la raison graphique et de la forme scolaire, et qui sont a la fois pregnants des ce niveau de la scolarite et de plus en plus importants dans la suite du cursus. Ceci conduit l’auteur a interroger et a nuancer la pertinence de la distinction ou du Grand Partage entre formes orales pratiques et formes scripturo-scolaires, pour rendre compte de ces processus de differenciation precoces et des suivants. Enfin, Pierre Roques et al. ont etudie les modes de gestion et d’usage de l’espace interpersonnel chez les enfants de petite section de maternelle. Ils ont mis en evidence trois modes de gestion de cet espace, dont la stabilite durant l’annee scolaire et la mise en relation avec les modalites de participation sociale permettent de penser qu’ils relevent d’un developpement comportemental contribuant a la construction et a la differenciation des capacites interactives des enfants. Ce dossier apporte donc des connaissances et reflexions nouvelles sur un objet, l’ecole maternelle, qui a ete recemment au centre de debats et controverses, qu’il ne manquera pas d’eclairer.