The distribution of fibronectin (FN), laminin (LM), hyaluronic acid (HA) and chondroitin sulfate (CS) were examined by peroxidase immunocytochemistry in long-tailed monkey embryos during the period of neural tube and notochord formation (stages 8-11). Reactivity for each component in the neuroepithelial basement membrane (BM) increased with advancing development. Discontinuous staining was observed in areas of epithelial-to-mesenchymal transformation, i.e. in dorsolateral sites of neural crest emigration and in the axial region of the primitive streak. The BM forming around the developing notochord also showed increased reactivity for FN, LM, HA and CS between stages 8 and 11. No staining occurred within the notochord. Stage-related increases in reactivity in the mesenchymal matrix was particularly notable for FN and HA which were ubiquitous throughout the mesoderm by stage 11. The results of this study are consistent with the proposed role of these components in maintaining epithelial integrity and providing a permissive substrate for cell migration during development. The observed temporal and regional staining patterns suggest that these glycoproteins and glycosaminoglycans are important morphogenetic factors in the macaque.
The distribution of integrin subunits alpha 6 and beta 1, and the alpha 6 beta 1 integrin ligand, laminin, was examined during somitogenesis in developmental stages 11, 13, and 16 in the long-tailed macaque, using peroxidase immunocytochemistry. Within differentiating somites in stage 11, alpha 6 expression was observed in the sclerotome, basal surface of dermamyotomal cells adjacent to the basal lamina and on scattered cells throughout the dermamyotome. In further advanced somites in stages 13 and 16, alpha 6 immunoreactivity became restricted to the myotome. alpha 6 was expressed on mesenchymal core cells within the myocele of undifferentiated epithelioid somites and the ventromedial wall of somites commencing differentiation at each stage. beta 1 distribution resembled that of alpha 6 in stage 11 somitic tissue, however, it remained present on myotome and sclerotome cells in the later stages, and was also expressed on dermatomal cells in stage 16. Laminin immunoreactivity, while more intense and prevalent than alpha 6 and beta 1 in each stage examined, occurred on the same somite cell populations as the 2 integrin subunits. These results show a defined distribution of alpha 6 on somitic tissue, and suggest this integrin is involved in somite differentiation. They also support a possible role for alpha 6 in myoblast formation and migration. Overlapping of beta 1 and laminin immunoreactivity with that of alpha 6 further suggests that alpha 6 pairs with beta 1 as a functional heterodimer for laminin in defined somitic regions.
Ovarian lymphatics of flying-foxes were traced to determine if they could transport hormones directly from ovary to ipsilateral uterine horn, thereby stimulating the localised endometrial growth which is characteristic of these animals. Intra-ovarian injections of ink and serial histological sections did not reveal any such connection. All major ovarian lymphatics and those from the cranial tip of each uterine horn drain cranially, terminating in 1 or 2 lymph nodes lying caudal to the ipsilateral kidney. For much of their course, the major ovarian lymphatics run in the adventitia of the ovarian venous sinus. This sinus encloses the coiled ovarian artery, which provides the major blood supply to the cranial end of the ipsilateral uterine horn. Some fine ovarian lymphatics run in the adventitia of the coiled ovarian artery. The enclosure of the coiled ovarian artery by the ovarian venous drainage is thought to provide the main route for transfer of steroids from ovarian vein to ovarian artery and thence to ipsilateral uterine horn. The ovarian lymphatics described here do not bypass the vascular pathway but provide an additional route for counter- or cross-current transfer of ovarian steroids to the ovarian arterial supply to the uterus.
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