Ocular Size And Shape Regulation During Development
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Ocular Size And Shape Regulation During Development
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Author : S.R. Hilfer
language : en
Publisher: Springer Science & Business Media
Release Date : 2012-12-06
Ocular Size And Shape Regulation During Development written by S.R. Hilfer and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012-12-06 with Science categories.
The eye has fascinated scientists from the earliest days of biological investigation. The diversity of its parts and the precision of their interac tion make it a favorite model system for a variety of developmental studies. The eye is a particularly valuable experimental system not only because its tissues provide examples of fundamental processes, but also because it is a prominent and easily accessible structure at very early embryonic ages. In order to provide an open forum for investigators working on all aspects of ocular development, a series of symposia on ocular and visual de velopment was initiated in 1973. A second purpose has been to foster communication between the basic research worker and the clinical community. It is our feeling that much can be learned on both sides from this interaction. The idea for an informal meeting allowing a maximum exchange of ideas originated with Dr. Leon Candeub, who supplied the necessary driving force that made the series a reality.
Role Of Growth Regulatory Pathways In Eye Development And Differentiation
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Author : Erika Lynn Wittkorn
language : en
Publisher:
Release Date : 2014
Role Of Growth Regulatory Pathways In Eye Development And Differentiation written by Erika Lynn Wittkorn and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014 with Cell differentiation categories.
Key genetic pathways are utilized for multiple functions within organisms. The novel functions of such pathways provide organisms with the ability to have increased complexity. During development, growth regulation and differentiation work together to sculpt the final shape of an organ. For this reason it makes sense why key genetic pathways would have function in not only growth regulation, but also differentiation. One pathway that may have this capability is the Hippo signaling pathway, a known growth regulatory pathway. This is a highly conserved pathway between insects and humans. Since Drosophila melanogaster is a favored genetic model in studying patterning and growth, we employ the use of this model system in order to understand the role of this known growth regulatory pathway's involvement in not only growth, but also in retinal development and differentiation. There are five major genes within the Hippo pathway, hippo (hpo), salvador (sav), warts (wts), mob as tumor suppressor (mats) and yorkie (yki). These components have been shown to be involved in growth, cell survival and are required to control organ size. Though the Hippo signaling pathway has been well researched for its involvement in growth and cell survival, its involvement in other developmental processes, such as differentiation is still unknown. This project aims to define the Hippo signaling pathways involvement in differentiation of the developing eye and deciphers the mechanism by which this pathway regulates differentiation. This was done by utilizing techniques such as the GAL4/UAS system and the `Flp-out' clone method. These techniques allowed us to assay the effects of Hippo pathway components on the differentiation of developing eye imaginal disc cells. Results displayed that the Hippo signaling pathway was indeed involved in the process of differentiation within the developing eye field. We found that when there was a loss of function of the Hippo signaling pathway, the co-activator yki was activated and in turn activated the downstream component wg, while suppressing the expression of retinal determination genes. wg can then suppress the progression of the morphogenetic furrow. This genetic signaling regulates the suppression of retinal differentiation within the developing eye. These results display that the Hippo signaling pathway has a novel function in cell differentiation.
Cellular Communication During Ocular Development
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Author : J. B. Sheffield
language : en
Publisher: Springer Science & Business Media
Release Date : 2012-12-06
Cellular Communication During Ocular Development written by J. B. Sheffield and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012-12-06 with Science categories.
The eye has fascinated scientists from the earliest days of biological investigation. The diversity of its parts and the precision of their interac tion make it a favorite model system for a variety of developmental studies. The eye is a particularly valuable experimental system not only because its tissues provide examples of fundamental processes. but also because it is a prominent and easily accessible structure at very early embryonic ages. In order to provide an open forum for investigators working on all aspects of ocular development. a series of symposia on ocular and visual development was initiated in 1973. A major objective of the symposia has been to foster communication between the basic research worker and the clinical community. It is our feeling that much can be learned on both sides from this interaction. The idea for an informal meeting allowing maximum exchange of ideas originated with Dr. Leon Canbeub. who supplied the necessary driving force that made the series a reality. Each symposium has concentrated on a different aspect of ocular development. Speakers have been selected to approach related topics from different perspec tives.
Current Catalog
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Author : National Library of Medicine (U.S.)
language : en
Publisher:
Release Date : 1982
Current Catalog written by National Library of Medicine (U.S.) and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1982 with Medicine categories.
First multi-year cumulation covers six years: 1965-70.
National Library Of Medicine Current Catalog
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Author : National Library of Medicine (U.S.)
language : en
Publisher:
Release Date : 1982
National Library Of Medicine Current Catalog written by National Library of Medicine (U.S.) and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1982 with Medicine categories.
Development Of The Ocular Lens
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Author : Frank J. Lovicu
language : en
Publisher: Cambridge University Press
Release Date : 2011-02-17
Development Of The Ocular Lens written by Frank J. Lovicu and has been published by Cambridge University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011-02-17 with Medical categories.
This book provides a comprehensive view of research in lens developmental biology, emphasising technical and molecular breakthroughs. Elucidation of the mechanisms that govern lens development has enabled us to understand how the normal lens forms and how developmental processes are involved in the maintenance of its normal structure, function and growth throughout life. This knowledge is fundamental to our understanding of many lens disorders. The ocular lens has also become a model for understanding the developmental biology of more complex organ systems. In this 2004 book, leading experts in lens cell biology and development discuss lens evolution, induction, morphology, the regulation of the lens cell cycle and fiber cell differentiation, as well as lens regeneration. This book is an authoritative treatment of the subject that will serve as a reference for graduate students and research scientists in developmental biology and in the visual sciences, as well as for ophthalmologists.
Investigation Of The Lens Regulated Signalling Pathway Controlling Embryonic Eye Growth
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Author : Jonathan Norman Smith
language : en
Publisher:
Release Date : 2015
Investigation Of The Lens Regulated Signalling Pathway Controlling Embryonic Eye Growth written by Jonathan Norman Smith and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with Crystalline lens categories.
The developing vertebrate lens is crucial for co-ordinating eye development and eye growth. It is thought that the lens controls eye growth through vitreous production – the gel-like fluid that fills and maintains correct eye shape. The ciliary body resides in the peripheral retina and is the main site of production of the vitreal components. It is proposed that the lens controls eye growth indirectly by controlling the development of the ciliary body and subsequently the vitreous. I have shown that WNT2B and RDH10 expression, genes involved in early eye development, is lost 3 hours after lens removal before overt reduction in eye size. The lens acts directly or indirectly to regulate WNT2B expression in the peripheral retina of the chick eye. It is unclear if the lens controls the expression of these genes individually or in a pathway. The expression of the retinal pattering genes, FOXG1, VAX1 and TBX5, are maintained in lens-less eyes demonstrating that the retina is correctly pattering in absence of the lens. I have found that in the chicken eye apoptosis is significantly up-regulated 3 and 6 hours after lens removal, however, previous work shows that apoptosis is normal in retinas 24 hours after lens removal indicating that up-regulation of apoptosis is transient. I have demonstrated that collagen II, a major component of the vitreous, is reduced in lens-less eyes before overt defects in eye size demonstrating that the lens is required for vitreal development. Tenascin, another vitreal component, is located in the peripheral retina showing that some aspects of ciliary body identity are maintained in les-less eyes and argues against peripheral tissue loss due to early apoptosis. Overall, the above work further supports the idea that the lens controls eye growth indirectly, through regulation of vitreous production, by controlling development of the ciliary body.
Scanning Electron Microscopy Studies Of Embryogenesis
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Author : Gary C. Schoenwolf
language : en
Publisher: Scanning Electron Microscopy
Release Date : 1986
Scanning Electron Microscopy Studies Of Embryogenesis written by Gary C. Schoenwolf and has been published by Scanning Electron Microscopy this book supported file pdf, txt, epub, kindle and other format this book has been release on 1986 with Science categories.
Understanding The Biological Pathways That Regulate Ocular Growth
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Author : Cindy Karouta
language : en
Publisher:
Release Date : 2020
Understanding The Biological Pathways That Regulate Ocular Growth written by Cindy Karouta and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020 with Eye categories.
Abstract: "The visual disorder myopia (short-sightedness) is brought about by a mismatch between the optical power of the eye and its axial length. This is due most commonly to excessive elongation of the eye which causes objects viewed at a distance to appear blurred as the focal plane falls in front of the neural layer of the eye (the retina) instead of on it. Myopia is now recognised as the leading cause of visual impairment and low vision world-wide, with some estimates indicating that half of the world's population may be myopic by 2050. Although our understanding of this visual disorder has dramatically improved over the past three decades, several critical questions remain. Central to this, and forming the basis of this thesis, is to understand the biological pathways controlling eye growth and how such pathways are modulated by external cues. Animal models have demonstrated that a diverse array of treatments, broadly categorised as optical, pharmacological and environmental, can inhibit the excessive growth associated with experimental myopia. Although diverse in their mechanisms of action, each of these treatments leads to a common set of biological outcomes when inhibiting myopia development, that of choroidal expansion and reduced scleral growth. Therefore, this thesis tests the hypothesis that, irrespective of the means by which growth is inhibited, such common physiological changes are driven by a conserved set of retinal signals. One retinal molecule that is consistently reported to be associated with the modulation of growth across several species is the immediate early gene (IEG) early growth response-1 (Egr-1). Therefore, this thesis explored if Egr-1 represents a conserved component of the growth regulatory pathway emanating from the retina by investigating whether its expression is consistently altered across a wide variety of growth modulating paradigms (Aim 1). Expanding on this, using whole-transcriptome analysis, this thesis investigated what other molecules, in addition to Egr-1, show a conserved response across five well-characterised growth inhibitory paradigms also investigated in Aim 1 (Aim 2). Following this, and expanding on Aim 1, this thesis investigates if the unexpected differences seen in the expression of Egr-1 between the two forms of myopic defocus (growth suppression), that of positive lens-wear and recovery from experimental myopia, could suggest mechanistic differences (Aim 3). This thesis tests if such differences may be explained by the previous state of eye growth and/or the initial size of the eye at treatment onset. Finally, this thesis examines whether the two primary forms of experimental myopia, namely form-deprivation myopia (FDM) and lens-induced myopia (LIM), are affected in a similar manner by the external environmental cue of light, and tests whether this response is driven by the same underlying mechanism, that of retinal dopamine release (Aim 4).This thesis reports the following major findings: Aim 1 - The retinal expression of Egr-1 showed a robust bi-directional response to a wide range of growth modulating paradigms. Specifically, its expression was down- regulated in response to enhanced growth, while being up-regulated in response to suppressed growth.Aim 2 - In addition to Egr-1, at the transcriptome level, significant overlap was observed in the expression profiles seen across the five diverse growth inhibitory treatments investigated. This overlap was even greater at the pathway level, with a distinct enrichment in processes associated with cell signalling and circadian entrainment. More broadly,the molecular profile of the retina during the onset and prevention of FDM was indicative of IEG activity, particularly the activity of Egr-1.Aim 3 - The unexpected down-regulation of Egr-1 mRNA levels seen following positive lens-wear remained even after adjusting for differences in the state of the eye before treatment onset. Instead, it appears that the retinal expression of Egr-1, although a powerful biomarker of changes in growth rates, may be insensitive to the direction of growth. Therefore, this aim will test whether a down-regulation in Egr-1 levels is the default response to any initial stimulus that alters ocular growth rates, irrespective of the direction of growth. Aim 4 - Exposure to bright light inhibits the development of LIM in a similar intensity- dependent manner as that seen for FDM, with this protective effect abolished byblocking the dopaminergic system using a pharmacological antagonist."
Principles And Practice Of Clinical Electrophysiology Of Vision Second Edition
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Author : John R. Heckenlively
language : en
Publisher: MIT Press
Release Date : 2006-04-07
Principles And Practice Of Clinical Electrophysiology Of Vision Second Edition written by John R. Heckenlively and has been published by MIT Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006-04-07 with Medical categories.
The long-awaited second edition of an authoritative reference on electrophysiologic vision testing, including detailed information on techniques and problems, basic physiology and anatomy, theoretical concepts, and clinical findings; with extensive new material. This authoritative text is the only comprehensive reference available on electrophysiologic vision testing, offering both practical information on techniques and problems as well as basic physiology and anatomy, theoretical concepts, and clinical correlations. The second edition, of the widely used text, offers extensive new material and updated information: 65 of the 84 chapters are completely new, with the changes reflecting recent advances in the field. The book will continue to be an essential resource for practitioners and scholars from a range of disciplines within vision science. The contributions not only cover new information—important material that is likely to become more important in the next decade—but also offer a long-range perspective on the field and its remarkable development in the last century. After discussing the history and background of clinical electrophysiology, the book introduces the anatomy of the retina and principles of cell biology in the visual pathways at the molecular, physiological, and biochemical levels. It relates these new findings to the techniques and interpretations of clinical tests, including the electro-oculogram (EOG), electroretinogram (ERG), and visual evoked potentials (VEP), which are discussed in detail, as are equipment, data acquisition and analysis, principles and protocols for clinical testing, diseases and dysfunction, and animal testing. Notable additions for this edition include chapters on the origin of electroretinogram waveforms, multifocal techniques, testing in standard laboratory animals, recent advances in analysis of abnormalities in disease, and the applications of these techniques to the study of genetic abnormalities.