Topic
Pecten oculi
About: Pecten oculi is a research topic. Over the lifetime, 101 publications have been published within this topic receiving 1922 citations.
Papers published on a yearly basis
Papers
TL;DR: The data suggest that endogenous BMPs have significant effects on the development of ventral optic cup structures, and are implicated in the regulation of signalling molecules such as retinoic acid and sonic hedgehog.
Abstract: The ventral region of the chick embryo optic cup undergoes a complex process of differentiation leading to the formation of four different structures: the neural retina, the retinal pigment epithelium (RPE), the optic disk/optic stalk, and the pecten oculi. Signaling molecules such as retinoic acid and sonic hedgehog have been implicated in the regulation of these phenomena. We have now investigated whether the bone morphogenetic proteins (BMPs) also regulate ventral optic cup development. Loss-of-function experiments were carried out in chick embryos in ovo, by intraocular overexpression of noggin, a protein that binds several BMPs and prevents their interactions with their cognate cell surface receptors. At optic vesicle stages of development, this treatment resulted in microphthalmia with concomitant disruption of the developing neural retina, RPE and lens. At optic cup stages, however, noggin overexpression caused colobomas, pecten agenesis, replacement of the ventral RPE by neuroepithelium-like tissue, and ectopic expression of optic stalk markers in the region of the ventral retina and RPE. This was frequently accompanied by abnormal growth of ganglion cell axons, which failed to enter the optic nerve. The data suggest that endogenous BMPs have significant effects on the development of ventral optic cup structures.
99 citations
TL;DR: In this paper a morphological study of the retinal vascular patterns in various species of domestic animals is reported and a classification of these patterns into four well-defined groups is described.
96 citations
TL;DR: Ultrasonography (US) and computed tomography (CT) were performed after routine ophthalmologic and ophthalmoscopic examinations in 190 eyes of six various diurnal raptor species and proved US to be a quick noninvasive imaging technique for detailed ocular diagnoses.
Abstract: Ultrasonography (US) and computed tomography (CT) were performed after routine ophthalmologic and ophthalmoscopic examinations in 190 eyes of six various diurnal (common buzzard [Buteo buteo L., 1758], n=20; common kestrel [Tinnunculus tinnunculus L., 1758], n=20) and nocturnal raptor species (barn owl [Tyto alba L., 1758], n=22; tawny owl [Strix aluco L., 1758], n=8; long-eared owl [Asio otus L., 1758], n=5; horned owl [Bubo bubo L., 1758], n=1); and domestic pigeons (Columba livia, Gmel., 1789; n=19), with a total of 95 individuals. Pathologic findings such as lens subluxation and luxation, intravitreal hemorrhage, detached retina, post-traumatic partial sequestration, or malformation of the pecten could be demonstrated with diagnostic imaging tools, while opacities of cornea or lens constrained direct ophthalmoscopic examination. The results proved US to be a quick noninvasive imaging technique for detailed ocular diagnoses. CT provided detailed information of the bony skull and bony scleral rings as well as adequate visualization of shape, size, and margination of the eye and lens. Nevertheless, CT was unable to differentiate subtle structures within the vitreous like the pecten oculi or hemorrhage. Biometric measurements were carried out to objectify imaging results. Results showed good correlation of depth and width of the anterior eye chamber, lens and vitreous, length of the bulbus, and the pecten but no correlation of cornea and posterior wall thickness was found.
70 citations
Book•
1 Jan 1965
61 citations
TL;DR: The question is discussed whether the avascularity of the avian retina may be due to the specific metabolic activity of the pecten, and whether the inverse transdifferentiation processes may be triggered by the peculiar microenvironment in the vitreous body.
Abstract: The pecten oculi is a convolute of blood vessels in the vitreous body of the avian eye. This structure is well known for more than a century, but its functions are still a matter of controversies. One of these functions must be the formation of a blood-retina barrier because there is no diffusion barrier for blood-borne compounds available between the pecten and the retina. Surprisingly, the blood-retina barrier characteristics of this organ have not been studied so far, although the pecten oculi may constitute a fascinating model of vascular differentiation and barrier maturation: Pectinate endothelial cells grow by angiogenesis from the ophthalmotemporal artery into the pecten primordium and consecutively gain barrier properties. The pectinate pigmented cells arise during development from retinal pigment epithelial cells and subsequently lose barrier properties. These inverse transdifferentiation processes may be triggered by the peculiar microenvironment in the vitreous body. In addition, the question is discussed whether the avascularity of the avian retina may be due to the specific metabolic activity of the pecten.
58 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 3 |
| 2020 | 2 |
| 2019 | 4 |
| 2017 | 4 |
| 2016 | 3 |
| 2013 | 3 |