PubMed Health⌕ Search

Biomedical subjects

J Sebag

Publications and source records attributed to J Sebag.

76 records · Page 5Linked to original sources
PubMedDate not supplied

Diabetic retinopathy. Pathogenesis and the role of retina-derived growth factor in angiogenesis.

Diabetic retinopathy results from a combination of systemic and ocular abnormalities. Vasodilation, basement membrane pathology, microaneurysms, abnormal blood flow and tissue oxygenation, connective tissue abnormalities, and retinal ischemia are all components of early diabetic retinopathy. The pathogenesis of neovascularization is discussed with respect to the effects of vasodilation, vascular leakage, vitreous changes, and retinal ischemia. The evidence supporting Michaelson's hypothesis that a chemical messenger from the retina provides the stimulus for neovascularization is cited. The sequence of events involved in angiogenesis are cellular and basement membrane changes, endothelial cell migration, endothelial cell proliferation, and vessel formation. The experimental evidence in support of a role for retina-derived growth factor as a mediator of these cellular events is reviewed.

Basement Membrane↗
PubMedDate not supplied

Seeing the invisible: the challenge of imaging vitreous.

Imaging the vitreous is an attempt to view what is by design invisible. The inability to adequately image vitreous hinders a more complete understanding of its normal structure and function and how these change in aging and disease. The combined use of more than one technique could provide better imaging for investigational and clinical purposes. Past and present imaging methodologies are summarized and research and clinical techniques that are currently in development for future applications, are discussed. Dark-field slit microscopy has been used to characterize vitreous anatomy, both within the vitreous body as well as at the vitreo-retinal interface. In addition to this methodology, slit-lamp biomicroscopy; direct, indirect, and scanning laser ophthalmoscopies; ultrasonography; optical coherence tomography; magnetic resonance and Raman spectroscopies; and dynamic light-scattering methodologies for noninvasive evaluation are presented. Dark-field slit microscopy enables in vitro imaging without dehydration or tissue fixatives. Optical coherence tomography enables better in vivo visualization of the vitreo-retinal interface than scanning laser ophthalmoscopy and ultrasonography, but does not image the vitreous body. Dynamic light scattering can determine the average sizes of vitreous macromolecules within the vitreous body as well as possibly image the posterior vitreous cortex once detached, while Raman spectroscopy can detect altered vitreous molecules, such as glycated collagen and other proteins in diabetic vitreopathy.

Eye Diseases↗
PubMedDate not supplied

Interfaces.

There are important similarities in molecular composition and structural organization of the interface between the vitreous and retina and that between the retina and retinal pigment epithelium. It is striking that the two most common causes of severe vision loss in the western world involve neovascularization at these interfaces; i.e., proliferative diabetic vitreo-retinopathy at the vitreo-retinal interface and exudative age-related macular degeneration at the retina-retinal pigment epithelium interface. Improved knowledge of the physiology of these interfaces will lead to a better understanding of the effects of aging and diseases, especially those that involve neovascularization. Such advances will no doubt result in new treatment strategies offering more effective therapy, and, even more importantly, perhaps providing prevention from these devastating causes of blindness.

Bruch Membrane↗