The molecular changes associated with the transition of melanoma cells from radial growth phase to vertical growth phase (metastatic phenotype) are not very well defined. Expression of the tyrosine-kinase receptor c-KIT progressively decreases during local tumor growth and invasion of human melanoma
Molecular mechanisms of parturition
✍ Scribed by F. Ferré
- Publisher
- Hindawi Publishing Corporation
- Year
- 1997
- Tongue
- English
- Weight
- 68 KB
- Volume
- 5
- Category
- Article
- ISSN
- 1064-7449
No coin nor oath required. For personal study only.
✦ Synopsis
The initial signal for triggering human parturition might be fetal but of trophoblastic origin. Concomitantly, this placental signal would have as its target not only the uterus but also the fetus by activating its hypothalamo-pituitary-adrenocortical axis. The latter would represent a second fetal signal which, at the fetomaternal interface, would amplify and define in time the mechanisms responsible for the onset of labor, implying changes in the myometrial and cervical extracellular matrix associated with the accession of the contractile phenotype for myometrial cells. At each phase of these processes in the utero-feto-placental system, the nature of these signals remains to be identified. Is there a single substance, or rather, and more likely, a combination of several?
We appear to be in the presence of dynamic systems of a neuro-immuno-hormonal type which are difficult to describe. Nevertheless, steroid hormones appear to coordinate their successive equilibriums until they become irreversible. Such irreversibility constitutes the essential sign of parturition. Infect. Dis. Obstet. Gynecol. 5:98-105, 1997.
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