Method for treating and processing whole chick embryos for autoradiography, immunocytochemistry and other techniques.

A method is presented for in situ treatment of whole chick embryos with drugs and immunocytochemical and fixative reagents that resembles conditions "in ovo." The chick embryo is placed in a "shell-less" culture system where it is contained by an agar ring allowing for treatment in vivo. The conceptus (embryo+membranes) is then mounted on a microporous membrane and inserted into a filter device connected to a three-way stopcock that permits fluids to be changed using syringes. The embryo is then processed in toto or after embedding and sectioning for light or electron microscopy. The proposed handling system decreases technical artifacts and changes in the topographic microanatomy produced by conventional manipulation of chick embryos. This method is useful also for directly observing and recording changes in the embryo during drug treatments and allows processing with dangerous reagents without their direct contact with the operator. It is simple, inexpensive and requires only minimal technical training.

Role of early migratory neural crest cells in developmental anomalies induced by ethanol.

The purpose of this work was to study the dispersion of early migratory neural crest cell (NCC) of chick embryos treated with ethanol concentration known to induce the Fetal Alcohol Syndrome (FAS). After a direct treatment with ethanol (250 mg/dl), there was a higher number of abnormal embryos than in the control group, showing neural and cardiac anomalies. After NC-1 immunostaining, ethanol-treated embryos showed smaller number of NCC at all neuraxis levels and presumptive NCC were frequently seen flowing towards the lumen of the neural tube. Present data support the view that ethanol impairment of migratory behaviour of NCC may explain certain anomalies of FAS such as those found at the cephalic end of the body, which is known to be largely derived from NCC.