title: Analysis of high-angle synchrotron x-ray diffraction patterns obtained from macular dystrophy corneas.
abstract: Six macular dystrophy corneas from six individuals were investigated by synchrotron x-ray diffraction. Immunochemical evidence demonstrated that five of the patients had type I macular corneal dystrophy and that one had type II. Analysis of the high-angle x-ray diffraction patterns showed that the intermolecular spacing of macular dystrophy corneal collagen increases with hydration from the dry state in a fashion similar to the intermolecular spacing of normal human corneal collagen. The high-angle x-ray diffraction pattern from all six corneas contained two "extra reflections" not obtained from other human corneas, normal or pathologic. The reflections, which arise from 4.61 and 9.62 A periodic structures, are independent of the type of macular dystrophy. Furthermore, their position is independent of corneal hydration. We propose that a glycosaminoglycan structure is the origin of the unique extra reflections.
authors.affiliation: Biophysics Group, Open University, Oxford Research Unit, Boars Hill, England.
authors.forename: A J
authors.initials: AJ
authors.lastname: Quantock
authors.forename: K M
authors.initials: KM
authors.lastname: Meek
authors.forename: E J
authors.initials: EJ
authors.lastname: Thonar
mesh_terms: D003094:Collagen / Q000737:chemistry*; D003315:Cornea / Q000737:chemistry*; D003317:Corneal Dystrophies, Hereditary / Q000378:metabolism*; D005260:Female; D006025:Glycosaminoglycans / Q000032:analysis; D006801:Humans; D007632:Keratan Sulfate / Q000378:metabolism; D008297:Male; D014961:X-Ray Diffraction / Q000379:methods*
chemical_list: D006025:Glycosaminoglycans; D003094:Collagen; D007632:Keratan Sulfate