The embryology of gut rotation.

Reconstitutive ability of axial tissue in early rat embryos after operations and culture in vitro.

Longitudinal incisions have been made in the axis of 10-day-old rat embryos (post-neurula stage with 5-10 pairs of somites) at mid-trunk levels, dividing the axis into right and left halves. The embryos have then been cultured in vitro by New's method and their ability to reconstitute tissues in each half has been studied. After 20 h culture at 37 degrees C, there was no longer any external sig...

Further analysis of the effect of ultra-violet irradiation on the formation of the germ line in Xenopus laevis.

Ultra-violet (u.v.) irradiation of the vegetal pole of newly fertilized eggs has three documented effects: reduction of primordial germ cells (PGCs), cytological damage to the vegetal hemisphere and disruption of the normal mechanism by which the vegetal yolk mass induces the formation of the dorsal axis of the embryo. In this study, we find that 90 degrees rotation of the egg for various perio...

Gut and nerve-cord interaction in sabellid regeneration.

Intestinal malrotations: a review and report of thirty cases.

Intestinal malrotation is a developmental anomaly affecting the position and peritoneal attachments of the small and large bowels during organogenesis in foetal life. It has been defined as absent or incomplete rotation and fixation of the embryonic gut around the superior mesenteric artery. In the present paper, we review the definition, history, embryology/aetiology, epidemiology, symptoms an...

The distribution of endocrine cell progenitors in the gut of chick embryos.

The aim of this experiment was to find out whether or not, at early stages of development, progenitors of the various types of gut endocrine cells are localized to one or more specific regions of the gastrointestinal tract. Transverse strips of blastoderm two to four somites in length were excised between the levels of somites 5 and 27 in chick embryos at 5- to 24-somite stages and were culture...