摘要:

Five neutral glycosphingolipids were isolated from human cataracts using silicic acid column chromatography and preparative thin-layer chromatography. Three of these glycolipids were partially identified by gas-liquid chromatography as glucosylceramide, lactosylceramide, and trihexosyl-ceramide. Two glucosamine-containing glycosphingolipids (one of which contained fucose) were also detected. One of these two lipids contained galactose, glucose, N-acetylglucosamine in the molar ratio of 2:1:1, while the other contained fucose, galactose, glucose, and N-acetylglucosamine with the molar ratio of 1:2:1:1. Dihydrosphingosine (sphinganine) was the major long-chain base detected in all these fractions. The fatty acids of these neutral glycosphingolipids were variable in chain length, although the majority of them were greater than 20 carbons. This represents the first time whereby a family of neutral glycosphingolipids has been detected in human cataracts. This is also the first demonstration of the existence of a neutral fucolipid in the lenses of any species.

ISSN:0271-3683    

DOI:10.3109/02713688208996345

出版商:Taylor&Francis    

年代:1982

数据来源: Taylor

摘要:

We attempted to induce corneal flattening in a baboon model by implanting donut-shaped hydrogel lenses in an intralamellar pocket created by a microkeratome. 7mm diameter hydrogels in five eyes produced corneal steepening from 3.4 to 22.5 diopters. Three to five months postoperatively the study was terminated and the corneas studied with correlative microscopy. There was an absence of inflammation, but the intralamellar pocket was lined with keratocytes, focal areas of epithelial implantation were found and the overlying corneal cap was normal.

ISSN:0271-3683    

DOI:10.3109/02713688208996346

出版商:Taylor&Francis    

年代:1982

数据来源: Taylor

摘要:

To better compare possible changes in soluble protein content during human cataractogenesis, microdissected sections from opaque and highly pigmented versus transparent parts of the lens were analyzed by high pressure liquid chromatography, isoelectric focusing, sodium dodecylsul-fate polyacrylamide gel electrophoresis, and tryptic mapping of radioiodinated peptides. Using this methodology, resolution of proteins and their tryptic peptides can be obtained from individual lens sections containing as little as 5–10μg of protein. Furthermore, the origin of each protein analyzed by these methods can be verified by comparison with tryptic peptide maps of previously purified human crystallins. Included are examples of how this technique can be used to characterize differences in protein composition from opaque versus transparent sections from different human lenses, as well as brunescent vs lightly-pigmented sections from the same human lens.

ISSN:0271-3683    

DOI:10.3109/02713688208996347

出版商:Taylor&Francis    

年代:1982

数据来源: Taylor

摘要:

We have measured the effects of hydrogen peroxide on the ability of the isolated rabbit cornea to maintain normal hydration during perfusion, on the structure of the endothelial cells, and on the redox state of glutathione and the activity of the hexose monophosphate shunt in these cells. Swelling of isolated corneas was immediate and severe upon exposure to 50μM H2O2in the absence of glucose, or to 200μM H2O2in the presence of glucose. The presence of glucose with 50μM H2O2delayed the onset of swelling for two hours and markedly decreased its severity. The concentration of glutathione in the endothelium, and its redox state, were unaltered by 50μM H2O2in the presence of glucose, but in its absence glutathione loss was significant and the fraction in the oxidized state was greatly increased. H2O2was removed from the medium by reaction with the cornea at a concentration-dependent rate. It was calculated that the reaction rate at 50μH H2O2was about twice that which could be accounted for by the increased yield of WADPH generated by the stimulation of the hexose monophosphate shunt. H2O2 may also react with endothelial cell membranes, which could account for the marked changes in cell structure seen in the scanning electron microscope.

ISSN:0271-3683    

DOI:10.3109/02713688208996348

出版商:Taylor&Francis    

年代:1982

数据来源: Taylor

摘要:

An ELISA method has been used to document antibody production by the ocular and lymph node cells of rabbits immunized intravitreally with ovalbumin. Simultaneous plaque assays were performed on many of the tissues. We found plaque forming cells in the ocular tissues by day 7. IgG producing cells, as detected by the ELISA assay, were not detected until day 10. Both IgG and IgM producing cells were present in the corneal and uveal tract suspensions throughout the remainder of the observation period. Lymph node and spleen IgG production was usually only detected early in the antibody response.

ISSN:0271-3683    

DOI:10.3109/02713688208996349

出版商:Taylor&Francis    

年代:1982

数据来源: Taylor

摘要:

Myeloperoxidase (MPO) activity was measured in rabbit cornea and iris-ciliary body to quantitate the infiltration and accumulation of polymorphonuclear leucocytes (PMN's) following an inflammatory stimulus.Following injection of clove oil into the cornea, MPO activity could be detected in the cornea at 6 hr, reaching a maximum at 12 hr, and falling to non-detectable levels at 72 hr., MPO activity was only detected in the iris-ciliary body 24 hr after intracorneal clove oil injection.MPO activity in the iris-ciliary body increased in a dose-dependent manner following intravitreal injection of endotoxin. No MPO activity could be detected in cornea.Topical administration of dexamethasone inhibited MPO activity in cornea and irisciliary body 24 hr after intracorneal clove oil and intravitreal endotoxin injection, respectively.Measurement of MPO activity in ocular tissues could provide a useful tool to quantitatively evaluate the severity and time course of inflammation.

ISSN:0271-3683    

DOI:10.3109/02713688208996350

出版商:Taylor&Francis    

年代:1982

数据来源: Taylor

摘要:

Low angle synchrotron X-ray diffraction patterns were obtained from the demembranated human corneal stroma. These patterns showed differences in the relative intensities of the meridional reflections compared to those obtained using bovine corneas. In particular, the first order reflection, conspicuously absent in the bovine pattern, is present in the human, although it is still only one third as intense as the first order in the pattern from rat tail tendon.Using phases deduced from the electron-optical images of negatively stained corneal collagens, a difference electron density map between bovine and human corneal collagen was drawn. The features in this map are explained in terms of a different inter-relationship between collagen and proteoglycans in the two species. The function of these species differences is unknown.

ISSN:0271-3683    

DOI:10.3109/02713688208996351

出版商:Taylor&Francis    

年代:1982

数据来源: Taylor

摘要:

After extraction of bovine corneal stroma with 1M CaC12and subsequent digestion of the insoluble residue with purified bacterial collagenase, two crude structural glycoprotein (SPG) fractions were obtained; one which precipitated upon dialysis against water of the collagenase solubilized material and the other which was extracted by 8M urea from the collagenase insoluble material. Amino acid analyses of these crude SGP fractions indicated that they were primarily non-collagenous but that very small amounts of collagen-derived amino acids were present. Upon gel filtration of these SGP fractions on Sepharose 4B-CL, void volume fractions were isolated from each of the crude fractions which were enriched, relative to the original crude fractions, in the collagen-derived amino acids. Carbohydrate analysis indicated that the void volume fractions had the properties of glycoproteins rather than proteoglycans. Upon disulfide reduction and SDS-PAGE, each of these fractions was resolved into five major protein bands with molecular weights of 155,000, 137,000, 117,000 82,000 and 34,000. Only the three largest bands contained the collagen derived amino acids. These data are consistent with the presence within bovine corneal stroma of a large structural glycoprotein complex comprised of at least five protein components associated through disulfide bonds. Collagen apparently is associated with three of these, either through covalent crosslinkage, or as part of the primary structure.

ISSN:0271-3683    

DOI:10.3109/02713688208996352

出版商:Taylor&Francis    

年代:1982

数据来源: Taylor

摘要:

Raman spectra were measured for cac-strain mouse (Nakano mouse) lenses in the various stages of cataract formation. The spectra were compared with those of normal mouse lenses of the corresponding ages. A significant difference was observed in the intensity of the Raman band due to an OH stretching mode of lens water (3390 cirri) between the spectra of cataractous lenses and those of normal lenses. The difference was already obvious in the very incipient stage of hereditary cataract and became more pronounced with cataract development. These observations clearly show that changes in lens water occur during cataractogenesis. We propose in this communication that the intensity change of the Raman band at 3390 cm−1may beveryuseful for the diagnostic marker of cataractous signatures.

ISSN:0271-3683    

DOI:10.3109/02713688208996353

出版商:Taylor&Francis    

年代:1982

数据来源: Taylor

摘要:

Lens epithelial cells were isolated from samples of C57BL/6 and CD-I mice at different ages between 1 and 5 months, and assayed for the level of N-acetyl-β-glucosaminidase and their ability to replicatein-vitro. The lens epithelial cells from C57BL/6 mice had a reduced replicative potential compared to other normal strains. A statistically significant decrease in active enzyme levels was demonstrated to be associated with increased animal age of C57BL/6 mice.

ISSN:0271-3683    

DOI:10.3109/02713688208996354

出版商:Taylor&Francis    

年代:1982

数据来源: Taylor