摘要:

Systematic investigations on time, site and mechanism of the periderm development are not yet available, although this superficial layer also appears to be of morphogenetic importance.Therefore, we investigated the surface epithelium (epidermis) of mouse embryos of days 9–12 of gestation using light- and electron-microscopic techniques. On early day 9 it is one-layered. On late day 9 the periderm starts to develop in the region of the upper limb buds, on early day 10 in the region of the lower limb buds, on late day 10 in the back and head regions, and on early day 11 in the ventral region. On day 11 the surface of the limb buds is completely covered by a periderm, in the other regions the periderm development is not yet completed on day 12. The formation of this surface layer starts in many regions and from many cells. The cells form flat, squamous processes that push over neighbouring cells. Subsequently, they detach from the basal lamina, migrate to the surface and adopt an endothelium-like shape. In the contact areas of the periderm cells we find almost exclusively tight junctions. From these findings it can be concluded that the periderm does not have a general protective function against the amniotic fluid, but that it initially protects against regions with a morphogenetically ‘active’ basal epithelium. A linkage at the basal layer via desmosomes and a well-developed cytoskeleton speak for an additional mechanical function. The occurrence of a protein-synthesizing and secreting apparatus suggests an influence on the composition of the amniotic fluid. Aresorbing activity cannot be demonstrated with morphological techn

ISSN:1422-6405    

DOI:10.1159/000146662

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

Albino mice were bled through the hearts by cardiac puncture and ½, 1/3 and ¼ mis of blood were taken out from 3 groups of animals, respectively. Half of the experimental animals were reinfused with 5% dextrose 1 h after bleeding. All were killed either 2, 5, 9, 24, 48 or 72 h after bleeding, and the phagosome numbers per 5 pigment cells counted and compared with control retinae. A severe decrease was evident after bleeding and the decrease leveled off 48 h afterwards. Reinfusion with dextrose had a positive beneficial effec

ISSN:1422-6405    

DOI:10.1159/000146663

出版商:S. Karger AG    

年代:1988

数据来源: Karger

ISSN:1422-6405    

DOI:10.1159/000146664

出版商:S. Karger AG    

年代:1988

数据来源: Karger

ISSN:1422-6405    

DOI:10.1159/000146665

出版商:S. Karger AG    

年代:1988

数据来源: Karger

ISSN:1422-6405    

DOI:10.1159/000146666

出版商:S. Karger AG    

年代:1988

数据来源: Karger

ISSN:1422-6405    

DOI:10.1159/000146651

出版商:S. Karger AG    

年代:1988

数据来源: Karger