Retinoids early development

As in the case of chicks, various methods have been used to treat amphibians with retinoids and for two experimental purposes first, to study early development, and second, to study limb development and regeneration. Obviously, these two types of experiments involve treatment at widely differing stages, and a large number of different species of amphibians have been used for limb regeneration studies. 

Wendling O, Chambon P, and Mark M (1999) Retinoid X receptors are essential for early mouse development and placentogenesis. Proceedings of the National Academy of Sciences of the USA9S, 547-51. 

Ruberte, E., Dolle, P., Chambon, P., Morriss-Kay, G. 1991a. Retinoic acid receptors and cellular retinoid binding proteins II. Their differential pattern of transcription during early morphogenesis in mouse embryos. Development 111, 45-60. 

Kraft, J. C., Schuh, T, Juchau, M., and Kimelman, D. (1994) The retinoid X receptor ligand, 9-cw-retinoic acid is a potential regulator of early Xenopus development. 

More background information can be found in two books dedicated to ISH (11,12). Note that retinoid receptor or binding-protem transcript distribution may also be analyzed by whole-mount ISH of digoxigenm-labeled riboprobes, a method that is particularly informative at early stages of development and is described in Chapter 5 and in refs. 12 and 22, In Chapter 18, Xu and Lotan describe the use of digoxigenin-labeled RAR riboprobes for ISH of paraffin-embedded tissue sections. 

The developing eye is not only highly vulnerable to vitamin A deficiency, but also an excess of exogenous RA is known to cause severe eye malformations [1, 2, 13, 25]. We analyzed the mechanism of retinoid-related ocular teratology and its normal correlate in early zebrafish and mouse embryos, and we conclude that for the proper formation of the ventro-dorsal retina dimension, the eye anlage has to contain both a RA-rich and a RA-poor region. 

Lammer EJ, Armstrong DL (1992) Malformations of hindbrain structures among humans exposed to isotretinoin (13-cw-retinoic acid) during early embryogenesis. In GM Monis-Kay (ed.) Retinoids in normal development and teratogenesis. Oxford University Press, Oxford, 281-295... 

In animals, both vitamin A deficiency and an excess of dietary vitamin A or retinoid analogs, at specific critical periods of development, can result in severe developmental defects, and may be lethal to the embryo. The differentiation of cells in the neural crest and the development of the head and sensory organs, nervous system, heart, limbs, and skeleto-muscular system are often affected. Birth defects of a similar nature have occurred in women exposed to excessive dietary vitamin A, or to pharmacologic retinoids for treatment of skin diseases, in early pregnancy. 

Treatment of cutaneous T-cell lymphoma can be topical skin-directed or systemic. Topical options are used in the early skin-localized stage of the disease and include emollients, steroids, UVB radiation, retinoids, and PUVA. PUVA can produce relatively long-lived remissions. However, it is also associated with short-term side effects of oral psoralen intake, including nausea, vomiting, inconsistent gastrointestinal absorption, and long-term complications such as photosensitivity and the potential for development of skin cancer... 

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