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The shape of the eye: why the eye is round
Title
The shape of the eye: why the eye is round.
Creator
Liebovitch, Larry S.
Date Issued
2005
PURL
http://purl.flvc.org/fau/165914
Subject Headings
Eye, Eye--Anatomy, Eye--Physiology
Format
Document (PDF)
A novel vertebrate eye using both refractive and reflective optics
Title
A novel vertebrate eye using both refractive and reflective optics.
Creator
Wagner, Hans-Joachim, Douglas, Ron H., Frank, Tamara M., Roberts, Nicholas W., Partridge, Julian C., Harbor Branch Oceanographic Institute
Date Issued
2009-01-27
PURL
http://purl.flvc.org/FCLA/DT/1779078
Subject Headings
Eye, Eye --Anatomy, Eye --Movements --physiology, Fishes --Sense organs, Marine animals --Physiology, Vision --Physiology
Format
Document (PDF)
New insights into the neuromodulatory role and potential action site of taurine in retinal neurons
Title
New insights into the neuromodulatory role and potential action site of taurine in retinal neurons.
Creator
Bulley, Simon, Charles E. Schmidt College of Science, Department of Biomedical Science
Abstract/Description
Taurine is the second most abundant amino acid in the CNS after glutamate and its functions have been found largely related to intracellular calcium ([Ca2+]i) modulation, osmoregulation, membrane stabilization, reproduction and immunity. The action of taurine has also been implicated in neurotransmission and neuromodulation though its specific sites of action are not fully understood. Isolated retinal neurons from the larval tiger salamanders (Ambystoma tigrinum) were used as a model to study...
Show moreTaurine is the second most abundant amino acid in the CNS after glutamate and its functions have been found largely related to intracellular calcium ([Ca2+]i) modulation, osmoregulation, membrane stabilization, reproduction and immunity. The action of taurine has also been implicated in neurotransmission and neuromodulation though its specific sites of action are not fully understood. Isolated retinal neurons from the larval tiger salamanders (Ambystoma tigrinum) were used as a model to study the neuromodulatory role of taurine in the CNS and to gain insights into its potential sites of action. A combination of techniques was used, including whole-cell patch clamp recording to study taurine's regulation of voltage-gated potassium (K+) and Ca2+ channels and Fluo-4AM Ca2+-imaging to study taurine's regulation of glutamate-induced [Ca2+] I,. Taurine was shown to suppress of glutamate-induced [Ca2+] l, in a dose dependent manner. This suppression was mostly sensitive to the glycine rece ptor antagonist Strychnine but insensitive to any GABA receptor antagonist. The remaining strychnine-insensitive effect was inhibited with the protein kinase A (PKA) inhibitor, PKI, suggesting that there was an additional metabotropic pathway. Moreover, using the protein kinase C (PKC) inhibitor, GF109203X, there was an enhancement in strychnine-insensitive taurine's regulation. Taurine inhibits voltage-gated Ca2+ channels in the retinal neurons and has a dual effect on voltage-gated K+ channels. Taurine causes an increase in K+ current amplitude which is further enhanced with PKI and blocked with GF109203X, suggesting that it is through a PKC-dependent pathway negatively controlled by PKA-dependent pathway., There is a suppression of K+ current by taurine with intracellular application of GF109203X, suggesting that the reduction is through a PKA-dependent pathway. With both PKC and PKA inhibitors there is no longer an enhancement in maximum amplitude but a shift of volt dependence on a hyperpolarizing direction. Taurine's enhancement of K+ current is blocked by the Kv1.3 subtype antagonist Margatoxin, with Kv1.3 accounting for the majority of delayed-rectifier sustained current in bipolar and amacrine cells, as well as 50% of ganglion cells. Interestingly, the enhancement of K+ current by taurine is blocked by 5HT2A antagonist MDL11939, suggesting that activation of PKC is through this metabotropic serotonin receptor subtype. The suppression of voltage-gated Ca2+ channels is reversed with a combination of MDL11939 and the 5HT1A antagonist NAN-190. These results provide the evidence that the natural effect of taurine in the retinal neurons might be dependent on the activation of both 5HT1A and 5HT2A receptors. The high apparent activity of taurine on 5HT receptors could have important implication for the actions of taurine in central brain in which taurine has been known to be beneficial for improving mental health, as well as learning and memory processes.
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Date Issued
2010
PURL
http://purl.flvc.org/FAU/2953206
Subject Headings
Biological transport, Eye, Physiology, Taurine, Physiological effect, Taurine, Therapeutic use, Central nervous system, Physiology
Format
Document (PDF)
effect of spatial attention on pupil dynamics
Title
The effect of spatial attention on pupil dynamics.
Creator
Daniels, Lori B., Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description
Although it is well known that the pupil responds dynamically to changes in ambient light levels, the results from this dissertation show for the first time that the pupil also responds dynamically to changes in spatially distributed attention. Using a variety of orientating tasks, subjects alternated between focusing attention on a central stimulus and spreading attention over a larger area. Fourier analysis of the fluctuating pupil diameter indicated that: 1) pupil diameter changed at the...
Show moreAlthough it is well known that the pupil responds dynamically to changes in ambient light levels, the results from this dissertation show for the first time that the pupil also responds dynamically to changes in spatially distributed attention. Using a variety of orientating tasks, subjects alternated between focusing attention on a central stimulus and spreading attention over a larger area. Fourier analysis of the fluctuating pupil diameter indicated that: 1) pupil diameter changed at the rate of attention variation, dilating with broadly spread attention and contracting with narrowly focused attention, and 2) pupillary differences required changes in attentional spread; there were no differences in pupil diameter between sustained broad and sustained spread attention. Given that broadly spread attention increases the relative activation of large receptive fields and narrowly focused attention increases the relative activation of small receptive fields (Balz & Hock, 1997), the results of this study indicate that these attentional effects on receptive field activation can be mediated by changes in pupil diameter. That is, under broad attention, the corresponding pupillary dilation observed would increase spherical aberration, blurring the image thereby reducing high spatial frequency information and decreasing the activation of relatively small cortical receptive fields compared to relatively large receptive fields. This increased perception of low spatial frequencies would be beneficial in cases where attention is spread over a large area. Alternatively, under narrow attention the resulting pupillary constriction reduces spherical aberration sharpening the image and preserving high spatial frequency information resulting in a relatively increased response of small receptive fields.
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Date Issued
2010
PURL
http://purl.flvc.org/FAU/1870692
Subject Headings
Visual perception, Eye, Physiology, Optics, Adaptive, Visual pathways
Format
Document (PDF)
Regulation of tear lipocalin and MMPs by sex hormones in rabbit lacrimal gland: Implication in dry eye disease
Title
Regulation of tear lipocalin and MMPs by sex hormones in rabbit lacrimal gland: Implication in dry eye disease.
Creator
Vellala, Kavyasri, Florida Atlantic University, Azzarolo, Ana Maria
Abstract/Description
Tear lipocalin (TL) (~18kDa), is one of the major proteins in rabbit lacrimal fluid. The aim was to study the regulation of tear lipocalin by sex hormones. Results indicate that sexually mature female rabbits have a significantly higher expression of TL than sexually mature male rabbits. TL expression was higher in sexually mature rabbits than the juvenile rabbits. No significant difference was seen among the juvenile female and male rabbits. Rabbits were also sham operated, ovariectomized...
Show moreTear lipocalin (TL) (~18kDa), is one of the major proteins in rabbit lacrimal fluid. The aim was to study the regulation of tear lipocalin by sex hormones. Results indicate that sexually mature female rabbits have a significantly higher expression of TL than sexually mature male rabbits. TL expression was higher in sexually mature rabbits than the juvenile rabbits. No significant difference was seen among the juvenile female and male rabbits. Rabbits were also sham operated, ovariectomized and ovariectomized followed by either estrogen or androgen treatment. Androgen treated rabbits expressed significantly higher amounts of TL when compared to the other groups. This study also focused on sex hormone regulation of the gelatinases MMP-2 and MMP-9. All four treated groups expressed MMP-2, but the estrogen treated rabbit showed the highest expression; however, only the estrogen treated rabbit expressed MMP-9 and no expression was seen in the other three groups.
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Date Issued
2005
PURL
http://purl.flvc.org/fcla/dt/13306
Subject Headings
Lacrimal apparatus--Diseases, Dry eye syndromes, Tears--Physiology, Rabbits--Physiology, Rabbits as laboratory animals
Format
Document (PDF)
Peroxiredoxin 3 and Methionine sulfoxide reductase A are Essential for Lens Cell Viability by Preserving Lens Cell Mitochondrial Function through Repair of Cytochrome c
Title
Peroxiredoxin 3 and Methionine sulfoxide reductase A are Essential for Lens Cell Viability by Preserving Lens Cell Mitochondrial Function through Repair of Cytochrome c.
Creator
Lee, Wanda, Florida Atlantic University, Kantorow, Marc, Charles E. Schmidt College of Science, Department of Biomedical Science
Abstract/Description
The central premise of this dissertation is that mitochondrial antioxidant enzymes are essential to lens cell viability by preserving lens cell mitochondria and protecting and/or repairing lens cell proteins, and two mitochondrial-specific antioxidant enzymes, Peroxiredoxin 3 (PRDX3) and Methionine sulfoxide reductase A (MsrA), are explored. In this dissertation, we will examine the expression ofPRDX3 in the human lens, its colocalization to the lens cell mitochondria, its ability to be...
Show moreThe central premise of this dissertation is that mitochondrial antioxidant enzymes are essential to lens cell viability by preserving lens cell mitochondria and protecting and/or repairing lens cell proteins, and two mitochondrial-specific antioxidant enzymes, Peroxiredoxin 3 (PRDX3) and Methionine sulfoxide reductase A (MsrA), are explored. In this dissertation, we will examine the expression ofPRDX3 in the human lens, its colocalization to the lens cell mitochondria, its ability to be induced by H20 2-oxidative stress, and speculate how PRDX3 function/sf could affect the lens. We will also examine the reduced levels of MsrA by targeted gene silencing and its effect on reactive oxygen species production and mitochondrial membrane potential in human lens cells to determine its role in mitochondrial function in the lens. Lastly, we will examine the ability of MsrA to repair and restore function to a critical mitochondrial protein, Cytochrome c. The collective evidence strongly indicates that the loss of mitochondrial-specific enzymes, such as PRDX3 and MsrA, are responsible for increased reactive oxygen species levels, decreased mitochondrial membrane potential, protein aggregation and lens cell death, and further indicates that mitochondrial repair, protective, and reducing systems play key roles in the progression of age-related cataract and other agerelated diseases.
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Date Issued
2008
PURL
http://purl.flvc.org/fau/fd/FA00000868
Subject Headings
Genetic regulation, Proteins--Chemical modification, Cellular signal transduction, Eye--Physiology, Mitochondrial pathology
Format
Document (PDF)
Spatial analysis and functional gene clustering between lens epithelium and fiber cells
Title
Spatial analysis and functional gene clustering between lens epithelium and fiber cells.
Creator
Cowell, Tracy L., Florida Atlantic University, Kantorow, Marc
Abstract/Description
Purpose. To identify genes important for maintaining the specialized functions of lens epithelial and fiber cells. Methods. The expression profiles of 22,215 genes between human lens epithelial and fiber cells were analyzed using oligonucleotide microarray hybridization and RT-PCR. Selected genes were functionally clustered using the EASE bioinformatics software package. Results. Analysis of microarray hybridizations revealed 1430 transcripts that were significantly increased and 901...
Show morePurpose. To identify genes important for maintaining the specialized functions of lens epithelial and fiber cells. Methods. The expression profiles of 22,215 genes between human lens epithelial and fiber cells were analyzed using oligonucleotide microarray hybridization and RT-PCR. Selected genes were functionally clustered using the EASE bioinformatics software package. Results. Analysis of microarray hybridizations revealed 1430 transcripts that were significantly increased and 901 transcripts that were significantly decreased. Microarray data was confirmed using RT-PCR on 11 randomly selected genes. Functional clustering of the identified gene expression patterns revealed altered gene expression in cellular pathways including oxidative stress, cell proliferation, and apoptosis. The methionine sulfoxide reductase class of enzymes were further analyzed and demonstrated to be expressed throughout the human body, indicating a significant protective role. Conclusions. These data reveal novel and previously identified gene expression differences that provide insight into those mechanisms that may be important for lens cell differentiation.
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Date Issued
2004
PURL
http://purl.flvc.org/fcla/dt/13193
Subject Headings
Gene mapping--Statistical methods, Eye--Physiology, Epithelium--Culture and culture media, Cell culture--Analysis
Format
Document (PDF)