Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.3 (collagenase)
 18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have previously recovered herpes simplex virus type 1 (HSV) from the corneas of latently infected mice by cultivation in vitro. It could be argued, however, that these data do not definitively distinguish between persistent and latent corneal infection. We have now used RNA hybridization in situ to resolve this question by determining the expression of HSV genes in the corneas of BALB/c mice during latent infection. Two to four months after topical corneal inoculation with HSV, when no active ocular disease or infectious virus was present, corneas were removed and digested with collagenase. Dissociated cells pooled from two corneas were hybridized with 3H- or 35S-labeled 2.6-kb single-stranded RNA probes to detect sense and antisense ICP-0 transcripts. Twenty-five percent of the pools hybridized with the probe for antisense ICP-0 (latency-associated transcript, LAT), while only 3% hybridized with the probe for ICP-0 (p less than 0.03). Of the cells in positive pools, 0.6-7.0% showed a positive hybridization signal for LAT. No infectious virus was found by culture of supernatants from the probed pools or control latently infected corneas. These data provide further evidence that HSV can establish a true latent infection in the mouse cornea.
Cornea 1992 Sep
PMID:Detection of herpes simplex virus type 1 latency-associated transcripts in corneal cells of inbred mice by in situ hybridization. 133 Apr 38

We report the occurrence of sterile corneal ulceration in 11 eyes of eight patients with collagen vascular diseases and dry eyes after cataract extraction with intraocular lens implantation. Keratolysis occurred after both extracapsular and intracapsular cataract extraction and appeared unrelated to the type of intraocular lens. Despite aggressive lubrication and other medical treatment, including systemic immunosuppressive agents, penetrating keratoplasty was often required. Although all eyes were saved, visual outcome was usually poor. The histopathologic finding of polymorphonuclear leukocytes localized near the areas of corneal dissolution provides evidence for the role of polymorphonuclear leukocyte-derived collagenase as a contributing factor in the pathogenesis of sterile corneal ulceration in these patients.
Cornea 1990 Oct
PMID:Sterile corneal ulceration after cataract extraction in patients with collagen vascular disease. 207 56

Cationic glucose oxidase, prepared by amidation of its free carboxylic groups, has prolonged retention in tissues, resulting in sustained release of hydrogen peroxide generated during oxidation of endogenous glucose. Increased levels of hydrogen peroxide can inhibit superoxide dismutase activity, thereby promoting reduction of transition metal ions, particularly iron and copper, by superoxide anions. Therefore, hydrogen peroxide can generate highly reactive hydroxyl radicals through a superoxide-driven Fenton reaction. Amidated glucose oxidase injected into rabbit cornea produces corneal opacification within 3-4 days and severe corneal damage by 7 days. Ultrastructural studies revealed typical tissue lesions observed in corneal melting. Heat-inactivated amidated glucose oxidase had no effect during the first 3-4 days. However, a gradual opacification occurred thereafter, resulting in some cases, in a severe opacity by 7 days. These results are consistent with an oxidative attack on corneal glycoconjugates by radicals derived from glucose oxidase-generated hydrogen peroxide during the first 3-4 days. Invading phagocytic cells are responsible for lesions observed with the inactive enzyme and for the progression of the initial lesions caused by the active enzyme. Stimulated phagocytic cells not only produce active oxygen species during the respiratory burst, but also release neutral collagenase and acid lysosomal hydrolases that contribute to and amplify the degradation of the extracellular matrix.
Cornea 1990 Apr
PMID:Role of active oxygen species in corneal ulceration. Effect of hydrogen peroxide generated in situ. 215 13

In a series of experiments, Golub et al. demonstrated that tetracyclines, but not other antibiotics, can inhibit mammalian collagenases and proposed that this property could be useful in treating diseases, such as periodontal disease (but also included certain medical conditions, e.g., corneal ulcers) characterized by excessive collagen degradation (J Periodont Res 1983, 1984 and 1985; Experientia 1984; Cornea 1984). One effect was the dramatic reduction of tissue collagenase activity within the gingival crevicular fluid (GCF) of periodontal pockets after administering a standard regimen of a tetracycline (e.g., 200 mg minocycline or 1000 mg tetracycline/day). The preliminary studies described below determined the effect of (1) low-dose (LD; 40-80 mg/day) orally administered minocycline on GCF collagenase activity and on the subgingival microflora (Exp. I), and (2) tetracycline-loaded monolithic fibers (TF) on collagenase activity in vitro (Exp. II). In Exp. I, GCF collagenase activity was reduced by 45 to 80% 2 weeks after initiating LD minocycline therapy, an effect that lasted for at least several weeks after stopping drug treatment. No consistent change in the relative proportions of G(+), G(-) and motile subgingival microorganisms was detected as a result of LD treatment suggesting that the reduction in GCF collagenase activity was a direct inhibition of the enzyme by the drug. In Exp. II, 3- and 6-mm lengths of TF in vitro established tetracycline concentrations in 250 microliters of 132 micrograms/ml, from 3-mm lengths, and 265 micrograms/ml, from 6-mm lengths, after an 18-hour incubation.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Tetracyclines inhibit tissue collagenases. Effects of ingested low-dose and local delivery systems. 300 Dec 66

Cornea cells were isolated from bovine corneae after collagenase treatment. Subcellular fragments were fractionated by density gradient centrifugation. The density gradient run was monitored by determination of the marker enzyme activities for mitochondria, plasma membranes, lysosomes and endoplasmatic reticulum, of the enzyme activities involved in keratan sulfate synthesis and of the protein content. The fractions were further investigated by electron microscopy. Two membrane fractions with keratan sulfate-synthesizing activity (UDP-N-acetylglucosamine:keratan-N-acetylglucosaminyl-transferase, UDPgalactose:keratan galactosyltransferase and keratan sulfotransferase) were detected: a heavy fraction separated from the other organells investigated and a light fraction exhibiting the same density as plasma membranes. The activities of the three enzymes were found in the same density gradient fractions with a similar distribution pattern between the fractions, which suggests a joint localization of these 3 enzymes at the same intracellular sites.
 ...
PMID:Biosynthesis of proteokeratan sulfate in the bovine cornea. 2) Isolation of subcellular membrane fragments from bovine cornea cells with keratan sulfate synthesizing activity. 622 57

Polymorphonuclear leukocytes (PMN) are important in corneal disease because of their role as effector cells in inflammation and ulceration. The favorable effect of citrate on corneal ulceration appears to result from inhibition of the PMN. Citrate does not enter the cells but chelates Ca2+ in the extracellular fluid and may promote a loss of some intracellular Ca2+. Isocitrate is the only tricarboxylic acid cycle intermediate that inhibits PMN, also by Ca2+ chelation. When isobutylcyanoacrylate is polymerized, a substance, probably formaldehyde, inhibitory to PMN, continuously leeches from the plastic. Although acetylcysteine has been reported to inhibit collagenase in vitro it has a direct effect of enhancing the respiratory burst and possibly degranulation of PMN stimulated by opsonized zymosan. Dexamethasone had no effect on PMN stimulation while prednisolone was partially inhibitory at high concentrations. Indomethacin exerts an inhibitory effect on all parameters of PMN stimulation. These studies clarify the site and mechanism of citrate action as well as show the importance of knowing the effect of drugs on the PMN.
Cornea
PMID:The effect of citrate and other compounds on PMN incubated in vitro: further studies on the site and mechanism of action of citrate. 657 89

Eleven patients with severe corneal disease have been operated with a collar-button-shaped keratoprosthesis and have been followed for 9-36 months. Two of the devices have been removed, but the remainder are securely in place. Six of the patients have benefitted substantially in terms of improved vision. The complications have been reviewed, and some factors for success have been identified. Thus, to keep the keratoprosthesis temporarily buried beneath tissue (conjunctiva or skin), application of collagenase-suppressing medication and reduction of evaporative damage to the wound around the device seem particularly important.
Cornea 1994 May
PMID:Some factors influencing outcome after keratoprosthesis surgery. 803 70

Cytochalasins B (CB), dihydroB (H2CB), and D (CD) were found to cause loss of fibronectin (Fn) from the cell surface of normal rabbit corneal fibroblasts, breakdown of F-actin-containing microfilament bundles ("stress fibers"), and increase levels of type I interstitial collagenase (MMP-1) in the medium. In contrast to the effects of plasmin, the cytochalasins caused withdrawal of cells from the Fn mesh but not total loss of the mesh, and the collagenase was essentially all in latent form. The results are consistent with the possibility that cytochalasins, like plasmin, perturb the alpha 5 beta 1 integrin (Fn) receptor. Unlike plasmin, which degrades Fn to result in such a perturbation, however, the cytochalasins are thought to do so by directly disrupting cytoplasmic F-actin microfilaments associated with focal contact adhesive structures, to result in changes in the Fn receptor that cause loss of Fn. Thus, plasmin acting extracellularly and cytochalasins acting intracellularly are both thought to be able to modulate the secretion (and possibly also the synthesis) of MMP-1 by corneal fibroblasts by perturbing the Fn receptor located in the focal contact. The presence of all active collagenase after treatment with plasmin, as opposed to latent collagenase after treatment with cytochalasin, supports the interpretation that the events of secretion and activation of collagenase can be uncoupled.
Cornea 1994 Jan
PMID:Regulation of corneal fibroblast MMP-1 secretion by cytochalasins. 813 7

Keratoconus is a noninflammatory corneal disorder characterized by gradual stromal thinning and astigmatism. Altered degradation of corneal extracellular matrix is a suggested etiology for this disorder. In the present study we established keratocyte cultures from normal and keratoconus corneas and investigated the roles that matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMP, TIMP-2) may play. After chemical modification (reduction and alkylation) to remove the inhibitor and activation of enzyme with p-aminophenylmercuric acetate (APMA), keratoconus-conditioned media displayed a significant increase (p < 0.05) in the total potential gelatinolytic activity when compared with normal culture media treated in a similar manner. Basal levels of gelatinolytic activity in keratoconus culture media (no reduction, alkylation, or APMA treatment), determined by two different assay methods, tended to be about twice that of normal cell cultures. By zymography, both keratoconus and normal cultures showed identical enzyme patterns, which represented MMP-2 (72 kDa) in its proform and, depending on the treatment of the media, varying amounts of activated MMP-2 (65 kDa). This suggests that the increased gelatinolytic activity in keratoconus was not correlated with an increased appearance of either the 65-kDa-activated form of MMP-2 or a new MMP species. In addition, no differences in the amount of MMP-2 were detected that could account for the increased activities in keratoconus cultures. However, a relative decline in the detectable TIMP levels in keratoconus cultures resulted in an apparent three-fold increase in the ratio of MMP-2/TIMP. Northern blots showed no significant changes in mRNA levels for MMP-1, MMP-2, MMP-3, TIMP, or TIMP-2. These data suggest that a possible alteration in the interaction between MMP-2 and TIMP may play a role in the increased gelatinolytic activity seen in keratoconus tissues.
Cornea 1994 Mar
PMID:Increased gelatinolytic activity in keratoconus keratocyte cultures. A correlation to an altered matrix metalloproteinase-2/tissue inhibitor of metalloproteinase ratio. 815 82

We examined the effects of doxycycline hyclate on epithelial healing in vivo in the rabbit alkali-burn model. Twelve 2-3-kg Dutch belted rabbits were divided into three groups and received standard bilateral alkali burns (1 N sodium hydroxide for 30 s in an 11-mm circular plastic well). In group 1, two rabbits (four eyes) served as untreated controls. In group 2, five rabbits (10 eyes) received doxycycline hyclate (1.5 mg/kg) orally daily for 14 days. In group 3, five rabbits (10 eyes) received doxycycline hyclate (5 mg/kg) orally daily for 14 days. The epithelial defects were drawn and photographed on alternate days, after fluorescein staining. At conclusion, extracts of the corneas were evaluated for collagenase activity. At 14 days, the mean percentage of epithelial defects results in groups 1-3 were 50.0, 50.7, and 7.1%, respectively. Using the Wilcoxon rank sum test (two tailed), the differences were found to be statistically significant (p = 0.0015). Preliminary data indicated that oral doxycycline administration also decreased the collagenase activity in corneas obtained from these animals. Our preliminary findings indicated that systematically administered doxycycline hyclate, 5 mg/kg/day, promotes corneal reepithelialization in the rabbit alkali-burn model, a result, perhaps, of the drug's ability to inhibit excessive collagenase activity.
Cornea 1993 Sep
PMID:Effect of doxycycline hyclate on corneal epithelial wound healing in the rabbit alkali-burn model. Preliminary observations. 830 57


1 2 Next >>