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In the interspecific hybridizations Phaseolus polyanthus (or Phaseolus coccineus cv.) x Phaseolus vulgaris, embryo abortion appears in 60 per cent of studied cases at globular stage, 4 to 8 days after pollination according to the crosses. From a bibliographic review, a histological study of the Phaseolus ovule development brings to the fore the major part of integuments and nucellus in the nutrition of the embryo and the albumen. The monitoring of Phaseolus ovular structure modifications allows the identification of nutriments transfer modes from zygote up to cotyledon stage. Comparison between the P. polyanthus female parent and P. polyanthus x P. vulgaris hybrid ovule development, enables structures responsible for disturbances in the feeding of the hybrid embryo to be defined. These are located essentially in the nucellus and the endothelium. The embryo rescue relies on the existence of a suitable in vitro culture technique. This technique has been developed for the early heart-s haped embryos of P. vulgaris, and is efficient for P. coccineus, P. polyanthus and for the intraspecific or interspecific hybrids which are easiest to obtain. Improving this technique is being examined to enable the regeneration of plants from globular embryos. An in vitro medium with a composition which varies over a period of time and which meets the globular embryo osmotic and nutritive needs, has been developed. The continual variation of the embryo nutrition during its in vitro development is achieved by a system, where two gelified media come into contact. In this setup, a diffusion of the components occurs from the richer to the poorer medium, until the concentrations reach a steady state. A study of the nutritional needs of the globular and heart shaped-embryos of P. vulgaris, was carried out to determine the role of plant growth regulators in embryo growth and morphological evolution. The contribution of magnesium, iron and calcium in the normal differentiation of globular emb ryos has been emphasized. The reduced nitrogen and carbon hydrate sources have been examined. Glutamin and asparagin appeared to be the preferential way for nitrogen assimilation. According to their concentrations, sucrose, maltose and glucose exert a different impact on globular embryos growth and development. For each studied embryonic stage globular and early heart-shaped, an improved medium has been suggested. The application of a brief dark period at the start of the culture followed by a light period, besides using a design that ensures the variation of the medium composition and which integrates the previously formulated inferences, enables 60 per cent of cultivated globular embryos to reach the cotyledon stage and 13 per cent to germinate. Interactions between on the one hand, the light conditions and on the other, the osmotic pressure and the hormonal composition are highlighted. Thanks to preliminary studies concerning the pre-acclimatization medium composition, the use of ho rmonal components will not be needed in the future.

Phaseolus --- Embryonic development --- in vitro. --- in vitro

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La phototoxicité (photo-irritation) cutanée est définie comme une réaction toxique aiguë causée par des produits chimiques photoréactifs après administration de ces produits par la peau et exposition de la peau à la lumière ambiante. L'essai in vitro de phototoxicité sur épiderme humain reconstitué (EhR) vise à identifier le potentiel phototoxique d'un produit chimique d'essai administré par voie topique sur des tissus épidermiques humains reconstitués, avec ou sans exposition à la lumière solaire simulée. On évalue le potentiel phototoxique en calculant la réduction relative de la viabilité cellulaire, c'est-à-dire le rapport entre les viabilités des cellules exposées au produit chimique d'essai en présence de lumière solaire simulée et en l'absence de cette lumière. Les produits chimiques identifiés par cet essai sont susceptibles d'être phototoxiques in vivo, après administration par voie topique sur la peau, les yeux ou d'autres épithéliums externes exposés à la lumière.

Toxicity testing --- In vitro.

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Fertilization in vitro, Human

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The birth of Louise Joy Brown - the world's first baby born following in-vitro fertilization - heralded a medical revolution. Forty years later, many thousands of babies are born each year following IVF. Assisted reproduction is a global industry with a multi-billion dollar turnover. It is a complex mix of science, clinical management, bioethics, and commercial imperatives. Many of the pioneers of IVF are still with us and have a fascinating tale to tell. Here, they relate the story of the development of IVF and related technologies in a way that will prove invaluable to future generations of practitioners seeking to understand the genesis of the specialty. This is not an academic history: rather it takes an informal and anecdotal approach; informing and entertaining for generations of past, present and future medical and scientific specialists of IVF, alongside the millions of parents, who celebrated the successes of IVF treatment worldwide.

Fertilization in vitro, Human.

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Fertilization in Vitro --- economics