摘要:

Dendritic ulcers, the commonest manifestation of herpes simplex epithelial keratitis (HSEK) are fractals. It is likely that their fractal properties alter if they progress to a geographic appearance.This study investigates the relationship of maximum ulcer diameter (Feret's diameter) to area (Dm) and perimeter fractal dimensions (Ds), parameters of the complexity of their areas and outlines respectively.For dendritic ulcers in the size range of 1.6–3.2 mm, Dm = 1.41±0.06 and Ds = 1.40±0.04 (mean±SD). With increasing ulcer size, a progressive divergence of the values of Dm and Ds occurred, such that values of 1.75 and 1.22 respectively were found at a maximum diameter of 8.4 mm. These results imply that as ulcers enlarge, their outlines become less irregular and they fill more of a 2-dimensional plane.Dm and Ds are useful parameters in quantifying the progression of HSEK from dendritic to amoeboid morphology and could have a role in the assessment of ulcer response to pharmacological intervention. A knowledge of the fractal properties of HSEK may increase understanding of the mechanisms of ulcer formation and viral spread.

ISSN:0271-3683    

DOI:10.3109/02713689309029221

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

The full-length cDNA of mouse K12 keratin was characterized by sequencing overlapping cDNA clones isolated from a mouse cornea cDNA library. Using Northern blot hybridization, the radio-labeled cDNA hybridized to a 1.9 kb mRNA from adult cornea, but not from other mouse tissues including snout, esophagus, tongue, and skin. During mouse development, corneas do not express K12 mRNA until 4 days postnatal when the epithelium begins to stratify as judged by Northern blot andin situhybridization.In situhybridization with3H-labeled cDNA probe and immunohistochemical studies with antibodies against a synthetic oligo-peptide deduced from rabbit K12 cDNA demonstrate that this mouse K12 keratin is expressed in all cell layers of adult corneal epithelium, and the suprabasal layers, but not the basal layer of the limbal epithelium. Epidermal growth factor (EGF) has been shown to promote epithelium stratification of cultured chicken and human corneasin vitro.To examine whether EGF can promote K12 expression, EGF was administered to neonatal mice. The results indicate that EGF retards K12 expression by corneal epithelial cells, even though it promotes corneal epithelial stratification during mouse development. Taken together, our results demonstrate that the expression of K12 keratin is cornea-specific, differentiation-dependent, and developmentally regulated.

ISSN:0271-3683    

DOI:10.3109/02713689309029222

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

Topical application of sulprostone, a preferential prostaglandin EP3receptor agonist, caused a dose-dependent reduction of the circadian elevation of intraocular pressure (IOP) in New Zealand albino rabbits which were entrained to 12-hr/12-hr light-dark environment. Corresponding to the effect on IOP, 0.2μg, 2μg, and 20μg sulprostone decreased the norepinephrine (NE) concentration in the aqueous humor in the dark phase. There was no breakdown of the blood-aqueous barrier. Bilateral applications of 2μg and 20μg sulprostone to entrained rabbits that had undergone unilateral, preganglionic transection of the cervical sympathetic trunk reduced the circadian IOP elevation in the intact eye, but caused little IOP change in the decentralized eye. These results indicate that the lOP-lowering effect of topical sulprostone in rabbits is dependent on sympathetic neural activity and that prejunctional inhibition of NE release may be an important mechanism of action.

ISSN:0271-3683    

DOI:10.3109/02713689309029223

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

Evidence has shown an activation of phosphatidylinositol 4,5-bisphosphate (PIP2) specific phospholipase C (PtdIns-PLC) by light in the vertebrate retina and rod outer segments (ROS), suggesting important roles for its two metabolites, 1,2-diacylglycerol (DG) and inositol-1,4,5-trisphosphate [Ins(1,4,5)P3]. DG activates protein kinase C (PKC) and Ins(1,4,5)P3releases bound intracellular calcium. Since Ca2+plays an important role in light adaptation, the presence of Ins(1,4,5)P3receptors in ROS may indicate a regulatory role of Ins(1,4,5)P3to the free Ca2+content. In the present study, we investigated the Ins(1,4,5)P3receptors in whole retinal membranes and several subcellular fractions prepared from bovine retinas. Scatchard analyses of binding data for retinal membrane preparations showed a single, high-affinity binding site with equilibrium dissociation constant (Kd) of 24±2 nM and maximal binding capacity (Bmax) of 353±15 fmol/mg protein at pH 7.4. Specific binding was found in both small and large synaptosomal preparations representing inner and outer plexiform layers, respectively. A detectable, but low abundance of Ins(1,4,5)P3-specific binding in ROS was observed at both pH 7.4 and 8.3, but no specific binding of Ins(1,4,5)P3was found in isolated outer segment discs. The binding of Ins(1,4,5)P3in ROS was reduced by addition of ATP, suggesting a regulatory role for this nucleotide. Addition of calcium, sodium, and potassium ions also reduced specific binding of Ins(1,4,5)P3. Immunocytochemical studies indicate intense staining in the inner segment and extending to the ROS. Inner and outer plexiform layers were also stained. These findings show that the Ins(1,4,5)P3receptor is present in photoreceptor cells and inner and outer plexiform layers in the vertebrate retina.

ISSN:0271-3683    

DOI:10.3109/02713689309029224

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

Previous studies have reported the expression of acidic fibroblast growth factor (aFGF) by rat, bovine, and human retinal pigment epithelium (RPE)in vivo.To critically examine the expression of aFGF by RPE cells, we studied the density dependence of steady-state levels of mRNA and protein expressionin vitro.Northern blot analysis demonstrated 5 transcripts ranging from 4.5 kB to 1 kB. Steady-state levels of all the transcripts decreased as a function of culture density. A polyclonal antibody was raised against recombinant human aFGF and affinity purified on aFGF coupled to AffiGel-10. The resulting antibody crossreacted with bFGF but not FGF-5, but this crossreactivity could be eliminated by absorption of the antibody on bFGF coupled to AffiGel-10. The final antibody preparation recognized only a single band at approximately 18.5 kD in lysates of RPE. Immunohistochemical staining with this antibody preparation demonstrated a marked dependence on cell density after 3 days in culture. Low culture density yielded cells staining moderately for aFGF, while confluent cells exhibited little or no staining. The reduction of aFGF from RPE cells in culture in a density-dependent fashion could also be demonstrated by Western blot analysis.

ISSN:0271-3683    

DOI:10.3109/02713689309029225

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

Overnight eye closure induces a shift in the nature and composition of the tear film, from a dynamic reflex tear-rich to a stagnant secretory IgA-rich layer. This is accompanied by the induction of a state of sub-clinical inflammation, as evidenced by increases in albumin levels, plasminogen activation, conversion of complement C3 to C3c, and the recruitment of polymorphonuclear (PMN) cells into the tear film. To determine the time course and functional relationship between these potentially interdependent processes, tear samples were collected from ten non-contact lens wearers after 1, 2, 3 and 5 hours of sleep. A subgroup of 6 subjects also self-collected tear samples after 8 hours of sleep. Tear samples were analysed for albumin by quantitative immunofixation assay, secretory IgA (sIgA) by radial immunodiffusion assay, plasmin-like activity using a chromogenic substrate, and complement C3 to C3c conversion by immunoblot assay. Epithelial and PMN cells in the precornea! tear film were recovered from corneal washings from the same subjects after 1, 3, 5 and 8 hours of sleep, and quantified. Results revealed that, unlike epithelial cells which exhibited a slow progressive accumulation as a function of the period of sleep, PMN cell concentration exhibited a lag phase, with recruitment occurring after between 3 and 5 hours of eye closure. This was preceded by plasminogen activation, increases in albumin and sIgA levels, and complement C3 to C3c conversion, all of which occurred within 1 to 3 hours after eye closure. Plasmin-like activity appeared to plateau after 3 hours and then decreased. These findings reveal a temporal sequence in the induction of sub-clinical inflammation in the closed eye, and suggest that complement conversion may produce the chemotactic factor(s) responsible for PMN cell recruitment in the closed-eye tear film.

ISSN:0271-3683    

DOI:10.3109/02713689309029226

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

The clinical impression that pre-existing diabetes exacerbates radiation injury to the retinal vasculature was studied in STZ diabetic rats. Half of 2 groups of streptozotocin (STZ)-induced diabetic rats and 1 group of normal animals had their right eyes irradiated with 1000 cGy of 90 KVP x-rays. The prevalence of acellular capillaries in trypsin digests of the retinal vasculature was quantified for cach of the 6 groups of animals at 6.5 months post-irradiation.The prevalence of acellular capillaries in both non-irradiated diabetic groups was significantly higher than in controls while the irradiated animals in cach of the three main categories showed a statistically significant increase compared to their non-irradiated equivalents. However, the net increase in acellular capillaries following irradiation was much greater in rats with an 8 month term of pre-existing diabetes (180%) than in those which had only been diabetic for 3 months (36%). The results of this study suggest a synergistic relationship between pre-existing diabetes and ionising radiation in the development of retinal vasculopathy, and that the potentiation of the vascular damage is dependent on the duration of diabeks prior to radiation exposure.

ISSN:0271-3683    

DOI:10.3109/02713689309029227

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

A confocal scanning laser ophthalmoscope was used to image the human fundusin vivoat a series of 32 sections from near the retinal surface to deep within the optic nerve head. The optical sections were digitized and aligned to compensate for eye movement during image acquisition and stored on a computer. This registered stack of optical sections was reconstructed using specialized computational software. The three-dimensional volume rendering of the stack of optical sections results in a new way to view thein vivooptic nerve in three dimensions. This technique is of clinical importance since structural factors of thelamina cribrosaof the optic nerve may be important in glaucomatous damage. There may be diagnostic potential in thein vivoobservation of the three-dimensional structure of the optic nerve.

ISSN:0271-3683    

DOI:10.3109/02713689309029228

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

We assigned the gene for tear lipocalin to the long arm of human chromosome 9. Polyadenylated RNA was extracted from lacrimal gland. The coding region for tear lipocalin was amplified, sequenced and used to probe a panel of somatic cell hybrid DNA by Southern blot analysis. Regional mapping was accomplished by probing a panel of subfragments of the indicated chromosome. Restriction of genomic DNA with EcoRI failed to reveal any bands corresponding to the human tear lipocalin gene in mouse-human hybrids all of which lack chromosome 9. Southern blot analysis of human-hamster hybrids demonstrated a human 5.6 kb TaqI restriction fragment that segregated to the q34-qter region of chromosome 9 and assigned the gene for tear lipocalin to this region. Structurally homologous proteins of the lipocalin family, human placental protein 14, human alpha 1 microglobulin, and human brain prostaglandin synthase, have been mapped to this region. We suggest that the gene for tear lipocalin is part of an important lipocalin superfamily gene cluster on chromosome 9 within band q34.

ISSN:0271-3683    

DOI:10.3109/02713689309029229

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

This study examines the high capacity binding of intact and carboxyl-terminal-truncated alpha A(αA) crystallin to two types of lens membrane preparations; membrane stripped of extrinsic protein and some lipid by extraction with urea and alkali and unextracted membrane isolated by centrifugation of total water insoluble protein on a sucrose gradient (native membrane). High capacity binding ofαA crystallin to the urea-treated membrane was seen once theαA substrate concentration reached about 1 mg/ml of media. The membrane bound up to one mg ofαA per mg of intrinsic protein (MP26) at a concentration of 5 mgαA/ml media, binding 5 to 10 times greater than that seen by others at saturation of the high affinity but low capacity binding sites. No apparent differences were seen between high capacity binding of carboxyl terminal-truncatedαA (by trypsin) and intactαA, although each crystallin could antagonize binding of the other. However, once membrane bound, neither crystallin appeared to grossly displace the other.Using the carboxyl terminal-truncated alpha crystallin as a model substrate, native membrane was seen to have a higher capacity to bind the truncated alpha crystallin than urea-extracted membrane and binding was better correlated with the preexistingαA content of the native membrane than its MP26 content. An artificial native membrane was prepared by prebinding the truncatedαA to urea-extracted membrane. This preparation bound more intactαA than urea-extracted membrane bearing no prebound crystallin. We conclude that lens native membrane possesses a high capacity to bind alpha crystallins and that this binding could be mediated through protein-protein interactions with alpha crystallin boundin situto the membrane as extrinsic protein.

ISSN:0271-3683    

DOI:10.3109/02713689309029230

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor