Browsing by Subject "Eye"

Now showing 1 - 10 of 11
  • Thumbnail Image
    Item
    Compensatory Role of Inositol 5-Phosphatase INPP5B to OCRL in Primary Cilia Formation in Oculocerebrorenal Syndrome of Lowe
    (Public Library of Science, 2013-06-21) Luo, Na; Kumar, Akhilesh; Conwell, Michael; Weinreb, Robert N.; Anderson, Ryan; Sun, Yang; Ophthalmology, School of Medicine
    Inositol phosphatases are important regulators of cell signaling, polarity, and vesicular trafficking. Mutations in OCRL, an inositol polyphosphate 5-phosphatase, result in Oculocerebrorenal syndrome of Lowe, an X-linked recessive disorder that presents with congenital cataracts, glaucoma, renal dysfunction and mental retardation. INPP5B is a paralog of OCRL and shares similar structural domains. The roles of OCRL and INPP5B in the development of cataracts and glaucoma are not understood. Using ocular tissues, this study finds low levels of INPP5B present in human trabecular meshwork but high levels in murine trabecular meshwork. In contrast, OCRL is localized in the trabecular meshwork and Schlemm's canal endothelial cells in both human and murine eyes. In cultured human retinal pigmented epithelial cells, INPP5B was observed in the primary cilia. A functional role for INPP5B is revealed by defects in cilia formation in cells with silenced expression of INPP5B. This is further supported by the defective cilia formation in zebrafish Kupffer's vesicles and in cilia-dependent melanosome transport assays in inpp5b morphants. Taken together, this study indicates that OCRL and INPP5B are differentially expressed in the human and murine eyes, and play compensatory roles in cilia development.
  • Thumbnail Image
    Item
    Generation of mice carrying a knockout-first and conditional-ready allele of transforming growth factor beta2 gene
    (Wiley, 2014-09) Ahmed, A. S. Ishtiaq; Bose, Gracelyn C.; Huang, Li; Azhar, Mohamad; Department of Pediatrics, Indiana University School of Medicine
    Transforming growth factor beta2 (TGFβ2) is a multifunctional protein which is expressed in several embryonic and adult organs. TGFB2 mutations can cause Loeys Dietz syndrome, and its dysregulation is involved in cardiovascular, skeletal, ocular, and neuromuscular diseases, osteoarthritis, tissue fibrosis, and various forms of cancer. TGFβ2 is involved in cell growth, apoptosis, cell migration, cell differentiation, cell-matrix remodeling, epithelial-mesenchymal transition, and wound healing in a highly context-dependent and tissue-specific manner. Tgfb2(-/-) mice die perinatally from congenital heart disease, precluding functional studies in adults. Here, we have generated mice harboring Tgfb2(βgeo) (knockout-first lacZ-tagged insertion) gene-trap allele and Tgfb2(flox) conditional allele. Tgfb2(βgeo/βgeo) or Tgfb2(βgeo/-) mice died at perinatal stage from the same congenital heart defects as Tgfb2(-/-) mice. β-galactosidase staining successfully detected Tgfb2 expression in the heterozygous Tgfb2(βgeo) fetal tissue sections. Tgfb2(flox) mice were produced by crossing the Tgfb2(+/βgeo) mice with the FLPeR mice. Tgfb2(flox/-) mice were viable. Tgfb2 conditional knockout (Tgfb2(cko/-) ) fetuses were generated by crossing of Tgfb2(flox/-) mice with Tgfb2(+/-) ; EIIaCre mice. Systemic Tgfb2(cko/-) embryos developed cardiac defects which resembled the Tgfb2(βgeo/βgeo) , Tgfb2(βgeo/-) , and Tgfb2(-/-) fetuses. In conclusion, Tgfb2(βgeo) and Tgfb2(flox) mice are novel mouse strains which will be useful for investigating the tissue specific expression and function of TGFβ2 in embryonic development, adult organs, and disease pathogenesis and cancer. genesis
  • Thumbnail Image
    Item
    High index of suspicion: diagnosing a carotid-cavernous fistula
    (BMJ, 2023-03-02) Sarkis, Yara; Worden, Astin; Schreiber, Torsten; Lapitz, Alvaro; Medicine, School of Medicine
    A woman in her 70s presented with acute bilateral retro-orbital headache, diplopia, chemosis and eye swelling. Ophthalmology and neurology were consulted after detailed physical examination and diagnostic workup including laboratory analysis, imaging and lumbar puncture. The patient was diagnosed with non-specific orbital inflammation and was started on methylprednisolone and dorzolamide-timolol for intraocular hypertension. The patient's condition improved slightly, but a week later, she developed subconjunctival haemorrhage in the right eye, which prompted investigation for a low-flow carotid-cavernous fistula. Digital subtraction angiography showed bilateral indirect carotid-cavernous fistula (Barrow type D). The patient underwent bilateral carotid-cavernous fistula embolisation. Her swelling improved considerably on day 1 after the procedure and her diplopia improved over the following weeks.
  • Thumbnail Image
    Item
    How Chlamydia trachomatis conquered gut microbiome-derived antimicrobial compounds and found a new home in the eye
    (National Academy of Sciences, 2019-06-18) Banerjee, Arkaprabha; Nelson, David E.; Microbiology and Immunology, School of Medicine
  • Thumbnail Image
    Item
  • Thumbnail Image
    Item
    Interstrain differences in the development of pyometra after estrogen treatment of rats
    (American Association for Laboratory Animal Science, 2009-09) Brossia, Lisa Jane; Roberts, Christopher Sean; Lopez, Jennifer T.; Bigsby, Robert M.; Dynlacht, Joseph R.; Pharmacology and Toxicology, School of Medicine
    This case report describes the unanticipated development of pyometra in Brown Norway rats after treatment with estrogen. Sprague Dawley and Brown Norway rats were ovariectomized and randomly assigned to treatment groups (subcutaneous implantation of either a capsule containing 20 mg 17beta-estradiol or an empty capsule, as a control). After irradiation of only the right eye, the rats were followed for several months in an attempt to determine the effects of estrogen on radiation cataractogenesis and investigate potential strain differences in this phenomenon. However, all Brown Norway rats that received estradiol treatment developed pyometra, whereas none the Sprague Dawley or control Brown Norway rats did. This case demonstrates the potential adverse effects of exogenous estrogen therapy, which are strain-specific in the rat. Caution should be taken when designing estrogen-related experiments involving Brown Norway rats and other potentially sensitive strains.
  • Thumbnail Image
    Item
    A NEW APPROACH FOR HUMAN IDENTIFICATION USING THE EYE
    (2010) Thomas, N. Luke; Du, Yingzi; Rizkalla, Maher; King, Brian
    The vein structure in the sclera, the white and opaque outer protective covering of the eye, is anecdotally stable over time and unique to each person. As a result, it is well suited for use as a biometric for human identification. A few researchers have performed sclera vein pattern recognition and have reported promising, but low accuracy, initial results. Sclera recognition poses several challenges: the vein structure moves and deforms with the movement of the eye and its surrounding tissues; images of sclera patterns are often defocused and/or saturated; and, most importantly, the vein structure in the sclera is multi-layered and has complex non-linear deformation. The previous approaches in sclera recognition have treated the sclera patterns as a one-layered vein structure, and, as a result, their sclera recognition accuracy is not high. In this thesis, we propose a new method for sclera recognition with the following contributions: First, we developed a color-based sclera region estimation scheme for sclera segmentation. Second, we designed a Gabor wavelet based sclera pattern enhancement method, and an adaptive thresholding method to emphasize and binarize the sclera vein patterns. Third, we proposed a line descriptor based feature extraction, registration, and matching method that is scale-, orientation-, and deformation-invariant, and can mitigate the multi-layered deformation effects and tolerate segmentation error. It is empirically verified using the UBIRIS and IUPUI multi-wavelength databases that the proposed method can perform accurate sclera recognition. In addition, the recognition results are compared to iris recognition algorithms, with very comparable results.
  • Thumbnail Image
    Item
    Ocular Hemodynamics and Glaucoma: The Role of Mathematical Modeling
    (Sage, 2013) Harris, Alon; Guidoboni, Giovanna; Arciero, Julia C.; Amireskandari, Annahita; Tobe, Leslie A.; Siesky, Brent A.; Ophthalmology, School of Medicine
    Purpose: To discuss the role of mathematical modeling in studying ocular hemodynamics, with a focus on glaucoma. Methods: We reviewed recent literature on glaucoma, ocular blood flow, autoregulation, the optic nerve head, and the use of mathematical modeling in ocular circulation. Results: Many studies suggest that alterations in ocular hemodynamics play a significant role in the development, progression, and incidence of glaucoma. Although there is currently a limited number of studies involving mathematical modeling of ocular blood flow, regulation, and diseases (such as glaucoma), preliminary modeling work shows the potential of mathematical models to elucidate the mechanisms that contribute most significantly to glaucoma progression. Conclusion: Mathematical modeling is a useful tool when used synergistically with clinical and laboratory data in the study of ocular blood flow and glaucoma. The development of models to investigate the relationship between ocular hemodynamic alterations and glaucoma progression will provide a unique and useful method for studying the pathophysiology of glaucoma.
  • Thumbnail Image
    Item
    Phenylthiourea Specifically Reduces Zebrafish Eye Size
    (Public Library of Science, 2012) Li, Zeran; Ptak, Devon; Zhang, Liyun; Walls, Elwood K.; Zhong, Wenxuan; Leung, Yuk Fai; Biochemistry and Molecular Biology, School of Medicine
    Phenylthiourea (PTU) is commonly used for inhibiting melanization of zebrafish embryos. In this study, the standard treatment with 0.2 mM PTU was demonstrated to specifically reduce eye size in larval fish starting at three days post-fertilization. This effect is likely the result of a reduction in retinal and lens size of PTU-treated eyes and is not related to melanization inhibition. This is because the eye size of tyr, a genetic mutant of tyrosinase whose activity is inhibited in PTU treatment, was not reduced. As PTU contains a thiocarbamide group which is presented in many goitrogens, suppressing thyroid hormone production is a possible mechanism by which PTU treatment may reduce eye size. Despite the fact that thyroxine level was found to be reduced in PTU-treated larvae, thyroid hormone supplements did not rescue the eye size reduction. Instead, treating embryos with six goitrogens, including inhibitors of thyroid peroxidase (TPO) and sodium-iodide symporter (NIS), suggested an alternative possibility. Specifically, three TPO inhibitors, including those that do not possess thiocarbamide, specifically reduced eye size; whereas none of the NIS inhibitors could elicit this effect. These observations indicate that TPO inhibition rather than a general suppression of thyroid hormone synthesis is likely the underlying cause of PTU-induced eye size reduction. Furthermore, the tissue-specific effect of PTU treatment might be mediated by an eye-specific TPO expression. Compared with treatment with other tyrosinase inhibitors or bleaching to remove melanization, PTU treatment remains the most effective approach. Thus, one should use caution when interpreting results that are obtained from PTU-treated embryos.
  • Thumbnail Image
    Item
    Protocadherin-17 Function in Zebrafish Retinal Development
    (Wiley, 2013) Chen, Yun; Londraville, Richard; Brickner, Sarah; El-Shaar, Lana; Fankhauser, Kelsee; Dearth, Cassandra; Fulton, Leah; Sochacka, Alicja; Bhattarai, Sunil; Marrs, James A.; Liu, Qin; Biology, School of Science
    Cadherin cell adhesion molecules play crucial roles in vertebrate development including the development of the retina. Most studies have focused on examining functions of classic cadherins (e.g. N-cadherin) in retinal development. There is little information on the function of protocadherins in the development of the vertebrate visual system. We previously showed that protocadherin-17 mRNA was expressed in developing zebrafish retina during critical stages of the retinal development. To gain insight into protocadherin-17 function in the formation of the retina, we analyzed eye development and differentiation of retinal cells in zebrafish embryos injected with protocadherin-17 specific antisense morpholino oligonucleotides (MOs). Protocadherin-17 knockdown embryos (pcdh17 morphants) had significantly reduced eyes due mainly to decreased cell proliferation. Differentiation of several retinal cell types (e.g. retinal ganglion cells) was also disrupted in the pcdh17 morphants. Phenotypic rescue was achieved by injection of protocadherin-17 mRNA. Injection of a vivo-protocadherin-17 MO into one eye of embryonic zebrafish resulted in similar eye defects. Our results suggest that protocadherin-17 plays an important role in the normal formation of the zebrafish retina.