9 research outputs found
The use of sulfur hexafluoride microbubbles for contrastâenhanced ocular ultrasonography of the pecten oculi
Morphological aspects and expression of estrogen and progesterone receptors in the interdigital sinus in cyclic ewes
A comparative ultrastructural study of the pecten oculi in adult, juvenile, and nestling yellowâlegged gulls, Larus michahellis (Naumann, 1840)
This study aimed at examining the histological structure of the pecten oculi in the adult yellowâlegged gull, Larus michahellis, and at two moments of postnatal development: during the posthatch (nestling) and juvenile periods. Particular attention was paid to differences in the diameter of vessels, the thickness of the basement membrane, and ultrastructural features of endothelial and pigmented stromal cells. Capillary endothelial cells displayed numerous microvillousâlike folds projecting from their internal and external surfaces. Intercellular spaces between capillaries were occupied by pigmented stromal cells. The ultrastructure of pecten oculi underwent noticeable changes during postnatal development. The examination of the capillaries in nestlings, juveniles, and adults revealed that the formation process of vessels and pigmented stromal cells did not complete itself in the posthaching phase. The prominent feature of endothelial cells of capillaries in nestlings was that the microvilli were longer than in juvenile and adult cells, and the capillary lumen was therefore reduced. In this sense, their pigmented stromal cells showed fewer melanosomes, lacked intercellular spaces, and cellular junctions could still be observed. These results provide evidence that the pecten oculi during the posthatching phase maintains immature morphological features consistent with a role of pigmented stromal cells in the bloodâretina barrier.This research was supported by the University of Alicante VIGROBâ186 and UAUSTI16â06 grants