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Microscopy Research and Technique Dec 1996The interphotoreceptor matrix (IPM) has in recent years been receiving much attention due to its delicate localization between the photoreceptors and the retinal pigment... (Review)
Review
The interphotoreceptor matrix (IPM) has in recent years been receiving much attention due to its delicate localization between the photoreceptors and the retinal pigment epithelium (RPE). The IPM is a resilient, structure forming and hydrophilic matrix composed of large glycoproteins and proteoglycans, which occupies the subretinal space between the photoreceptors. The IPM is most likely assembled with components synthesized by all the surrounding cell types: the photoreceptor cells, the RPE cells, and the Müller cells. It has been implied to be involved in the development and maintenance of photoreceptors, and as a major factor in retinal adhesion. Therefore, it has been thoroughly studied also in several models of photoreceptor degeneration. Comparative studies have revealed some remarkably consistent features between different species, such as the presence of the rod and cone specific matrix domains. Studies made in the IPM of several species have measured large fluctuations in ion concentrations as a result of changes in illumination. In some species, these ionic fluctuations coincide with the intriguing dynamic redistributions of IPM constituents that can be visualized with histochemical techniques. It can be hypothesized that because of the intensive biochemical activity and the frequent changes in metabolic states of rods and cones the IPM may act as a kind of "buffer." These studies have brought a new extracellular aspect to photoreceptor studies and a new perspective to photoreceptor-RPE research.
Topics: Animals; Extracellular Matrix; Humans; Photoreceptor Cells; Pigment Epithelium of Eye; Retinal Degeneration
PubMed: 9016449
DOI: 10.1002/(SICI)1097-0029(19961215)35:6<463::AID-JEMT5>3.0.CO;2-J -
Scientific Reports Feb 2016We developed new optic devices - singly-doped luminescence glasses and nanoparticle-coated lenses that convert UV light to visible light - for improvement of visual...
We developed new optic devices - singly-doped luminescence glasses and nanoparticle-coated lenses that convert UV light to visible light - for improvement of visual system functions. Tb(3+) or Eu(3+) singly-doped borate glasses or CdS-quantum dot (CdS-QD) coated lenses efficiently convert UV light to 542 nm or 613 nm wavelength narrow-band green or red light, or wide-spectrum white light, and thereby provide extra visible light to the eye. In zebrafish (wild-type larvae and adult control animals, retinal degeneration mutants, and light-induced photoreceptor cell degeneration models), the use of Tb(3+) or Eu(3+) doped luminescence glass or CdS-QD coated glass lenses provide additional visible light to the rod and cone photoreceptor cells, and thereby improve the visual system functions. The data provide proof-of-concept for the future development of optic devices for improvement of visual system functions in patients who suffer from photoreceptor cell degeneration or related retinal diseases.
Topics: Animals; Disease Models, Animal; Light; Nanoparticles; Optical Devices; Photoreceptor Cells; Retinal Degeneration; Ultraviolet Rays; Zebrafish
PubMed: 26860393
DOI: 10.1038/srep20821 -
Photochemistry and Photobiology 2012The human eye is constantly exposed to sunlight and artificial lighting. Light transmission through the eye is fundamental to its unique biological functions of... (Review)
Review
The human eye is constantly exposed to sunlight and artificial lighting. Light transmission through the eye is fundamental to its unique biological functions of directing vision and circadian rhythm and therefore light absorbed by the eye must be benign. However, exposure to the very intense ambient radiation can pose a hazard particularly if the recipient is over 40 years of age. There are age-related changes in the endogenous (natural) chromophores (lipofuscin, A2E and all-trans-retinal derivatives) in the human retina that makes it more susceptible to visible light damage. Intense visible light sources that do not filter short blue visible light (400-440 nm) used for phototherapy of circadian imbalance (i.e. seasonal affective disorder) increase the risk for age-related light damage to the retina. Moreover, many drugs, dietary supplements, nanoparticles and diagnostic dyes (xenobiotics) absorb ocular light and have the potential to induce photodamage to the retina, leading to transient or permanent blinding disorders. This article will review the underlying reasons why visible light in general and short blue visible light in particular dramatically raises the risk of photodamage to the human retina.
Topics: Aging; Gene Expression Regulation; Humans; Light; Photoreceptor Cells; Retina
PubMed: 22582903
DOI: 10.1111/j.1751-1097.2012.01174.x -
Harvest and storage of adult human photoreceptor cells: the vibratome compared to the excimer laser.Current Eye Research Jul 1998To develop a method using the vibratome and the excimer laser to harvest a sheet of human photoreceptor cells from the retinas of cadaveric donors.
PURPOSE
To develop a method using the vibratome and the excimer laser to harvest a sheet of human photoreceptor cells from the retinas of cadaveric donors.
METHODS
Adult human photoreceptor cells were harvested as intact sheets from the retinas of cadaver eyes using a vibratome or excimer laser. The sheets were embedded in 50% gelatin (in minimum essential medium and 300 mM sucrose) and stored at 4 degrees C. The morphology, integrity, viability and sterility of the harvested photoreceptor cells was studied.
RESULTS
Light and scanning electron microscopy demonstrated sheets of adult human photoreceptor cells with an outer nuclear layer and inner and outer segments with either method of harvest. The initial viability of the outer nuclear layer, harvested an average of 28.2 h after death, was > or =94.7%. Sheets stored up to 72 h after harvest maintained a viability of > or =86.5%. The sheet of cells harvested with the vibratome frequently fragmented (n = 25, 35%) during passage through the delivery cannula in contrast to the excimer laser. Harvested sheets were sterile when the gelatin powder was irradiated prior to reconstitution.
CONCLUSIONS
Intact, viable adult human photoreceptor cell sheets can be isolated from the retina of a cadaver using either the vibratome or the excimer laser and stored up to 72 h at 4 degrees C. With the vibratome, there is damage to the outer segments of the photoreceptors, the sheets are fragile, and the harvest of specimens is time-consuming as only one or two specimens can be harvested from a single donor retina. These technical limitations are avoided with the excimer laser.
Topics: Cadaver; Cell Survival; Esterases; Humans; Lasers; Microscopy, Electron, Scanning; Photoreceptor Cells; Preservation, Biological; Specimen Handling
PubMed: 9678421
DOI: No ID Found -
The Journal of Neuroscience : the... Oct 1992We have generated transgenic flies expressing R7 cell-specific opsins in the major class of photoreceptor cells of the Drosophila retina and characterized their spectral...
We have generated transgenic flies expressing R7 cell-specific opsins in the major class of photoreceptor cells of the Drosophila retina and characterized their spectral properties using high-resolution microspectrophotometry and sensitivity recordings. We show that the Rh3 and Rh4 opsin genes encode UV-sensitive opsins with similar spectral properties (lambda max = 345 nm and 375 nm), and that Rh3 corresponds to the R7p and R7marg class of visual pigments. We have also generated Rh3 and Rh4 isoform-specific antibodies and present an R7 cell map of the Drosophila retina. In a related set of experiments, we show that it is possible to coexpress two different visual pigments functionally in the same cell and produce photoreceptors that display the summed spectral response of the individual pigments. These findings open up the possibility of tuning an animal's visual behavior by targeted expression of combinations of opsin genes to selective types of photoreceptors.
Topics: Animals; Animals, Genetically Modified; Color Perception; Drosophila melanogaster; Photoreceptor Cells; Promoter Regions, Genetic; Rhodopsin; Rod Opsins
PubMed: 1403087
DOI: 10.1523/JNEUROSCI.12-10-03862.1992 -
Nature Oct 1979
Topics: Action Potentials; Adaptation, Physiological; Animals; Calcium; Cytosol; Dark Adaptation; Photoreceptor Cells
PubMed: 481607
DOI: 10.1038/281407c0 -
Biological Reviews of the Cambridge... Feb 2003Over a century ago workers such as J. Lubbock and K. von Frisch developed behavioural criteria for establishing that non-human animals see colour. Many animals in most... (Review)
Review
Over a century ago workers such as J. Lubbock and K. von Frisch developed behavioural criteria for establishing that non-human animals see colour. Many animals in most phyla have since then been shown to have colour vision. Colour is used for specific behaviours, such as phototaxis and object recognition, while other behaviours such as motion detection are colour blind. Having established the existence of colour vision, research focussed on the question of how many spectral types of photoreceptors are involved. Recently, data on photoreceptor spectral sensitivities have been combined with behavioural experiments and physiological models to study systematically the next logical question: 'what neural interactions underlie colour vision?' This review gives an overview of the methods used to study animal colour vision, and discusses how quantitative modelling can suggest how photoreceptor signals are combined and compared to allow for the discrimination of biologically relevant stimuli.
Topics: Animals; Behavior, Animal; Color Perception; Photoreceptor Cells; Photoreceptor Cells, Invertebrate
PubMed: 12620062
DOI: 10.1017/s1464793102005985 -
Quarterly Reviews of Biophysics May 1975
Review
Topics: Adenosine Triphosphatases; Amino Acids; Animals; Cell Membrane; Light; Mathematics; Membranes; Molecular Conformation; Photoreceptor Cells; Protein Conformation; Retinal Pigments; Rhodopsin; Species Specificity; Spectrophotometry; Spectrophotometry, Ultraviolet; X-Ray Diffraction
PubMed: 127191
DOI: 10.1017/s0033583500001785 -
International Review of Neurobiology 1993
Review
Topics: Adaptation, Ocular; Animals; Humans; Photoreceptor Cells; Retina; Vertebrates
PubMed: 8463064
DOI: 10.1016/s0074-7742(08)60568-1 -
BioEssays : News and Reviews in... Apr 2006Light can kill the photoreceptors of the eye, not only very bright direct sunlight, but more moderate illumination if the light is present continuously. Recent... (Review)
Review
Light can kill the photoreceptors of the eye, not only very bright direct sunlight, but more moderate illumination if the light is present continuously. Recent experiments show that rod apoptosis can be triggered by strong and constant activation of transduction, and that death can be prevented if transduction is inhibited even though the eye is illuminated. Vitamin A deficiency and genetically inherited diseases, such as some forms of retinitis pigmentosa and Leber congenital amaurosis, appear to kill like this: transduction is activated at a high rate and continuously, and this causes the rods to die. Why does transduction kill? Our best guess is that continuous activation produces a prolonged lowering of the Ca(2+) concentration, which is also thought to kill neurons in tissue culture and during the development of the nervous system. To prevent death in constant light, rods have evolved protective mechanisms including modulation of channels and ion transport to keep the Ca(2+) from going too low. Prolonged light exposure also causes migration of transduction proteins from one part of the cell to another and a reversible shortening of the rod outer segments, the part of the cell that contains the pigment rhodopsin. All of these mechanisms are at work in the normal eye to reduce transduction and prevent the Ca(2+) concentration from dropping too low for too long a time. That most of us retain our vision our entire lives is a testament to their effectiveness.
Topics: Animals; Cell Death; Humans; Light; Photoreceptor Cells; Retinal Rod Photoreceptor Cells; Signal Transduction; Vitamin A
PubMed: 16547945
DOI: 10.1002/bies.20382