effect of gamma irradiation on the developing medulla oblongata of the chick embryo

The morphological and histological changes following one integral dose [100 rads] of gamma rays of the developing medulla oblongata were evaluated in chick embryos. The study was carried out on 120 eggs [40 control and 80 irradiated]. Half of the embryos [control and irradiated] were sacrificed on the 12th day of incubation and the other half on the 16th day. Histopathological examination of the irradiated embryos in both ages showed evidence of retardation of growth in the form of reduction in the size of the medulla of 12 days irradiated embryo with changes in the shape of the fourth ventricle. Also, there was reduction in the size of some nuclei with decrease in the cell density. Other nuclei were ill defined with necrotic neuroblastic cells and shrinked neuroglial cells in between. In 16 days irradiated embryos the medulla increased in size. Some nuclei became dispersed, irregular in shape and hardly seen. Also, the neuroblastic and the neuroglial cells were surrounded by clear cavitation [edema]. Moreover, there were gliosis [fibrosis] and edema in between the neuroblastic cells of both ages. These changes resulted in loss of the cytoarchitectural pattern of the irradiated medulla oblongata. The present results were compared to those of previously published investigations

Effect of gamma-irradiation on the development of the femur of the chick embryo

In this work 90 fresh fertile Dokki-4 eggs were used. The eggs were divided into two groups. The first group [30 eggs] was regarded as control. The second group [60 eggs] was irradiated with a single dose [50 rads] of gamma rays on the 48 hours of incubation. The embryos were extracted on the 14th and 19th days of incubation, decalcified and fixed in Bouin's fluid for 7 days. Paraffin sections were prepared in the usual manner and stained with Hx and E. The femur of 14 and 19 days irradiated chick embryos showed evidence of retardation of growth, as diminution of the length and deformity of the shape of the femur. Thin periosteum with interrupted bone trabeculae were present among the changes seen in the femur. Also, wideness of the bone marrow cavity with necrosis of its content were found. The osteoblasts and the osteocytes appeared small in size with decrease in their number