摘要:

Previous studies have suggested that the plasminogen activator (PA)/plasmin system has important roles in the pathogenesis of epithelial defects and stromal ulceration. The current studies were performed to localize PA species and identify them as tissue-type PA (tPA) or urokinase-like PA (uPA) as the two have distinct regulatory properties potentially related to the mechanisms of defect formation and ulceration. To determine the locations and types of PA species, antibodies to tPA or to uPA or the drug amiloride (a drug that inhibits uPA but not tPA) were incorporated into fibrin/fib-ronectin (Fn) clots overlying frozen sections to block regional fibrinolysis. Normal rabbit eyes showed tPA activity in association with corneal epithelium, corneal endothelium, and ciliary body/iris. After epithelial scrape or alkali burn, corneal tPA activity was detected initially in the defect zone colinear with fibrin/Fn and was symmetrical to resurfacing epithelium. The observation that initial fibrinolysis occurs in the defect zone, known to contain fibrin/Fn, suggests that tPA from blood (limbal vascular endothelium) and/or from corneal epithelium has become bound to (and activated on) the fibrin/Fn. PA activity was also associated with the leading edges of migrating epithelium post-scrape and post-burn and was not inhibited by antibodies to either tPA or uPA but was inhibited by amiloride. After complete closure of the primary defect post-scrape, only tPA appeared to be associated with the epithelium in that all PA activity was inhibited by antibodies to tPA. The observation that leading edge activity post-burn, in correlation with the formation of secondary defects, continues to be inhibitable by amiloride but not by antibodies to tPA suggests that uPA remains abnormally on the leading edge, and that sustained uPA activity in that location results in inappropriate degradation of subepithelial fibrin/Fn to result in a defect. Successful regulation of uPA activity at the leading edge of corneal epithelium post-burn would be expected to be useful therapeutically in the healing of epithelial defects and the prevention of stromal ulceration.

ISSN:0271-3683    

DOI:10.3109/02713689109001747

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

Cyclic AMP production in response to agonists which act at a variety of receptors to either stimulate or inhibit cyclic AMP production has been studied in intact, dissected ciliary processes from rabbit eyes after unilateral surgical removal of the cervical ganglion. Cyclic AMP responses to stimulatory ligands vasoactive intestinal peptide (VIP), isoproterenol, and forskolin and inhibitory agonists neuropeptide Y (NPY), the synthetic somatostatin analogue SMS 201-995, and alpha-adrenergic agents were investigated in tissues from normal eyes and compared to the same responses in tissues from sympathetically denervated eyes. Neither stimulated cyclic AMP production nor inhibition of stimulated cyclic AMP production was significantly different in tissues from denervated vs. normal eyes. Inhibition of VIP-stimulated cyclic AMP production by epinephrine and paraaminoclonidine in tissues from both normal and denervated eyes was blocked by the alpha2-adrenergic antagonist yohimbine but not by the alphai-adrenergic antagonist prazosin. These data indicate that the VIP, NPY, somatostatin, and alpha2- and betaa-adrenergic receptors which regulate cyclic AMP production in rabbit ciliary processes are postjunctional and suggest that ligands known to modulate cyclic AMP levels in this tissue may exert effects on aqueous humor formation independently of adrenergic innervation.

ISSN:0271-3683    

DOI:10.3109/02713689109001748

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

Nonpigmented epithelial (NPE) and pigmented epithelial (PE) cells were carefully dissected from both human and rabbit ciliary processes and have been maintained in vitro and partially characterized by morphology and immunocytorhemical techniques using polyclonal and monoclonal antibodies against S-100 proteins, collagen type I and type III. The tissue distribution of these proteins was studied in formalin fixed deparaffinized tissue sections of human and rabbit eyes by immunoperoxidase staining techniques. Both NPE and PE cell lines from human and rabbit showed hexagonal morphology by light microscopy; distinct granules containing pigment could be visualized in the PE cell lines, but not in the NPE cells. Antibodies against S-100 proteins stained NPE layer intensely and PE layer slightly in the human tissue sections. The staining was less intense in rabbit tissues than human tissues. The ciliary body stroma was positive for collagen type TTI and negative for collagen type I or S-100.

ISSN:0271-3683    

DOI:10.3109/02713689109001749

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

Monoclonal antibodies to the bovine aA-crystallin were developed and used to probe the relationship between aA-crystallin and the bovine lens fiber cell Plasma Membrane-Cytoskeleton Complex (PMCC). Superficial bovine lens cortex was washed by repeated homogenization/centrifugation to remove“soluble protein.”The resulting Plasma Membrane-Cytoskeleton Complex was covalently immobilized to inert resin, and extensively buffer washed. SDS PAGE and immunoblot analysis of both the covalently immobilized PMCC and of the sequentially-generated subcellular fractions shows that most of the lens alpha crystallin is“soluble”, and readily extracted with physiologic buffers. However, this data also shows that 1) Non-alpha crystallins are progressively and quantitatively extracted from the PMCC with buffer, 2) An irreducible level of non-covalently bound alpha crystallin is achieved which cannot be readily extracted from the PMCC, even with 2 M urea, 1% NP40 or 0.4M KC1.Electron microscope level immunocytochemistry was performed on both the covalently immobilized PMCC, as well as on buffer-extracted thick frozen sections, using monoclonal antibodies to theαA-crystallin. The results show a very heavy labelling of both intermediate filaments and beaded filaments, but little or no labelling of fiber cell membranes.The data presented argues that a subtraction of the totalαA-crystallin is strongly associated with the fiber cell cytoskeleton complex, and constitutes a quantitatively major component of the lens cytoskeleton fraction.

ISSN:0271-3683    

DOI:10.3109/02713689109001750

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

Cynomolgus monkeys underwent unilateral panretinal scatter photocoagulation (PRP) and/or nasal and temporal horizontal retinal meridional photocoagulation (HRMP) with xenon arc or argon or krypton laser light. Shortly thereafter, in the PRP-treated eyes, accommodative responsiveness to topical eserine and electrical stimulation of the Edinger-Westphal nucleus (EWN) was diminished, accommodative responsiveness to intramuscular (i.m.) pilocarpine was enhanced, and the number of muscarinic receptors in the ciliary muscle was reduced compared to the contralateral controls. In most instances, these parameters returned to normal over 6–12 wks and the abnormalities could be induced again by another round of PRP. However, in some PRP-treated eyes, accommodative responsiveness to EWN stimulation and topical eserine remained subnormal permanently (>1 yr). Shortly after HRMP alone, accommodative responses to i.m. pilocarpine, topical eserine, and central stimulation did not differ markedly in the treated and control eyes. Morphologic studies 1 to 78 wk following PRP revealed that myelinated and unmyelinated nerves within the entire circumference of the choroid and ciliary muscle were severely damaged early on. The number of unmyelinated nerves between the individual ciliary muscle fibers was drastically reduced, those which remained were swollen or deteriorated, and agranular synaptic vesicles were rarely seen. Thereafter, the nerves in the choroid and ciliary muscle gradually regenerated. Following HRMP, only the choroidal nerves which passed through the photocoagulated areas and the ciliary muscle nerves in the corresponding meridians showed signs of deterioration, and there was minimal effect on the physiologic responses examined. These findings collectively indicate that intraocular parasympathetic denervation of the ciliary muscle is produced by PRP, although all nerve types are likely damaged.

ISSN:0271-3683    

DOI:10.3109/02713689109001751

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

The pearl mutant mouse is hypopigmented and exhibits a significantly elevated dark-adapted (DA) threshold in comparison to the congenic wild-type mouse. The primary cause of the elevated DA threshold is not known. The subcellular immunolocalization of arrestin/S-antigen reflects the state of adaptation of rod photoreceptors. In this study, quantitative immunoelectron microscopy was used to examine the subcellular distribution of arrestin in wild-type and pearl rods as a function of light exposure. The goal was to determine whether arrestin distribution within rods of pearl and wild-type mice responds to background luminance in a comparable manner. The level of arrestin immunolabeling in DA (unilluminated) rods of pearl retinas was indistinguishable from that measured in wild-type rods. By contrast, arrestin immunolabeling in light-adapted (LA) pearl rod outer segments (ROS) was significantly greater than in wild-type LA ROS. Relative to DA ROS, arrestin labeling density increased 1.6 fold in wild-type ROS following light adaptation, as compared to a 4 fold increase in pearl ROS. These data suggest that although arrestin levels in DA pearl rods are indistinguishable from that of DA wild-type rods, net changes in arrestin immunolocalization inresponse to light exposurereflect the effects of the pearl mutation at the level of the rod outer segment. The possible implication of this finding is discussed in view of the proposed role of arrestin in the down-regulation of the enzymatic cascade of phototransduction.

ISSN:0271-3683    

DOI:10.3109/02713689109001752

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

The polyamines putrescine, spermidine and spermine are necessary for cellullar growth and directly involved in cellular differentiation and cell death. The hypothesis that extracellular polyamine levels in rabbit aqueous humor could be used as biomarkers for trauma after eye surgery was investigated.Changes in polyamine levels in rabbit aqueous humor were measured after anterior chamber lens implantation and compared to normals. The measurements were made by reversed phase HPLC and 9-fluo-renylmethyl chloroformate and fluorescence detection.An increase in protein concentration followed by a white blood cell mobilization in the aqueous humor is a response to trauma to the eye. Therefore, the polyamine levels were compared to the aqueous levels of protein and leukocytes. Three days postoperatively a significant increase in spermidine was observed and a significant correlation between elevated protein levels and elevated spermine as well as total polyamines were noticed. No correlation between a high number of leukocytes and high polyamine levels were found.The results suggest that polyamines are evident markers for surgical trauma response, but not necessarily correlated to the postoperative inflammatory phase and the infiltration of inflammatory cells.

ISSN:0271-3683    

DOI:10.3109/02713689109001753

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

Lenses were obtained from the eyes of four different classes of Chordates, including Mammalia (rat, mouse, cow, human), Aves (chicken), Amphibia (tiger salamander), and Osteichthyes (steelhead), as well as from one Mollusca (squid). Buffer soluble, urea soluble and urea insoluble fractions were prepared from each, and probed by western blot analysis for the presence of the lens fiber cell 115 and 49 kD beaded filament proteins. Application of both polyclonal and monoclonal antibodies revealed that an immunologic homologue to the bovine fiber cell 115 kD protein is present in all examples of Chordates tested, and that this homologue possessed properties very similar to those of its bovine counterpart. Both monoclonal and polyclonal antibodies revealed an immunologically cross-reactive homologue in squid as well, but suggested that the squid protein had a native molecular weight of closer to 70–80 kD.A monoclonal antibody to the bovine 49 kD beaded filament protein was successful at identifying an immunologic homologue to this protein in mouse, chicken, and tiger salamander.Ultrastructural analysis of rat, human, and fish lenses showed that a beaded filament was present in these lenses, which was indistinguishable from that seen in the bovine lens. In the squid a filamentous, beaded structure was observed, but it differed from that seen in the bovine lens.We conclude from the data presented that the beaded filament, and its constituent proteins, are well-conserved. This data should facilitate the identification of lens cytoskeletal proteins and structure in a wide range of animal models, and establish that probes for these proteins may be of broad applicability.

ISSN:0271-3683    

DOI:10.3109/02713689109001754

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

Understanding tumor growth patterns has implications for prognosis as well as for response and susceptiblity to treatment. The antibody Ki-67 was used as a marker of cycling cells and bromodeoxyuridine (BrdUrd) was used as a marker of proliferating cells to characterize the cycling and proliferative rates of cells from human choroidal melanoma. The BrdUrd labeling indices varied from 0–1.1% and the Ki-67 labeling indices ranged from 0–3.03%. Linear regression modeling showed good correlation defined by the equation: Ki-67 index−0.237 + 1.63×BrdUrd labeling index with r = 0.919. Correlations between these indices and clinical and histologic parameters were not significant.

ISSN:0271-3683    

DOI:10.3109/02713689109001755

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

Enzymatically active lens multicatalytic proteinase complex bound [HJiPr.P-F after incubation for 3 hours at ambient temperature. Label was associated with the lowest molecular weight band (Mr22,000) on sodium dodecyl sulfate polyacrylamide gels. This binding was inhibited by preincubation of the enzyme with the cysteine-directed reagent, p-chloromercuri-benzoate, which inhibits all three hydrolytic activities of the enzyme. Leupeptin, which inhibits the arginyl-hydrolyzing component, but not the iP2-P-F-inhibitable leucyl-hydrolyzing component of the enzyme, does not inhibit [H]iPr2P-F binding. These data suggest that the leucyl-hydrolyzing component of the lens multicatalytic proteinase complex is localized to the 22,000 Mrsubunit and is a member of the thiol-dependent subclass of serine proteinases.

ISSN:0271-3683    

DOI:10.3109/02713689109001756

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor