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Query: UMLS:C0022568 (keratitis)
 5,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Since the early 1960s, axenic culture and the development of procedures for the induction of encystation have made Acanthamoeba spp. superb experimental systems for studies of cell biology and differentiation. More recently, since their roles as human pathogens causing keratitis and encephalitis have become widely recognized, it has become urgent to understand the parameters that determine differentiation, as cysts are much more resistant to biocides than are the trophozoites. Viability of trophozoites of the soil amoeba Acanthamoeba castellanii (Neff), is conveniently measured by its ability to form plaques on a lawn of Escherichia coli. Use of confocal laser scanning microscopy with Calcofluor white, Congo Red or the anionic oxonol dye, DiBAC4(3) or flow cytometry with propidium iodide diacetate and fluorescein or oxonol provides more rapid assessment. For cysts, the plaque method is still the best, because dye exclusion does not necessarily indicate viability and therefore the plate count method has been used to study the sequence of development of biocide resistance during the differentiation process. After two hours, resistance to HCl was apparent. Polyhexamethylene biguanide, benzalkonium chloride, propamidine isethionate, pentamidine isethionate, dibromopropamine isethionate, and H2O2 and moist heat, all lost effectiveness at between 14 and 24 h after trophozoites were inoculated into encystation media. Chlorhexidine diacetate resistance was observed at between 24 and 36 h. The molecular biology and biochemistry of the modifications that underlie these changes are now being investigated.
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PMID:Encystation in Acanthamoeba castellanii: development of biocide resistance. 1124 85

An 8-month-old 3-kg (6.6-lb) sexually intact male cat was evaluated for chronic refractory keratitis and a corneal plaque that developed after treatment with a corticosteroid-containing ophthalmic preparation. Pertinent ophthalmic findings included blepharospasm, conjunctivitis, corneal vascularization, and a tan raised corneal plaque with a dense and gritty composition. Lamellar keratectomy was performed to excise the plaque. The cornea healed with mild scarring. Histologic examination revealed extensive coagulation necrosis and mineralization of the corneal stroma with increased inflammatory cells, blood vessels, and fibrosis, which is compatible with a diagnosis of mineralized corneal sequestrum. The history suggested chronic feline herpesvirus-1 (FHV-1)-induced keratoconjunctivitis as the underlying cause. Topical corticosteroid administration may have potentiated the preexisting corneal necrosis and initiated mineralization. To our knowledge, mineralization of a corneal sequestrum in a cat has not been reported in a clinical case but has been reported in cats experimentally infected with FHV-1.
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PMID:Mineralized corneal sequestrum in a cat. 1175 95

Recently it has been shown that selective subconjunctival macrophage depletion reduced the incidence and severity of stromal herpes simplex virus (HSV) keratitis in mice. In this study, we examined the effect of conjunctival macrophage depletion on the corneal and systemic T-cell-mediated immune response. BALB/c mice were treated with subconjunctival injections of dichloromethylene diphosphonate (Cl2MDP)-liposomes (Cl2MDP-LIP) or phosphate-buffered saline (PBS) 7 and 2 days before corneal infection with 105 plaque-forming units (PFU) of HSV-1 (KOS strain). Interferon (IFN)-gamma, interleukin (IL)-2, and IL-4 production in the cornea was analysed by enzyme-linked immunosorbent assay (ELISA), and cytokine mRNA levels (IFN-gamma, IL-4) were measured by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). Cell culture supernatants from submandibular lymph nodes were analysed by ELISA for expression of IFN-gamma, IL-2, and IL-4 and by bioassay for IL-6. The HSV-1-specific proliferative response of lymphocytes from regional lymph nodes and the delayed-type hypersensitivity (DTH) response were tested after corneal infection. Virus-neutralizing antibody titres and HSV-1-specific immunoglobulin G (IgG)2a/IgG1-ratios were measured. Cytokine mRNA expression (IFN-gamma, IL-4) and secretion (IFN-gamma, IL-2, IL-4) in the corneas were decreased after HSV-1 corneal infection in the macrophage-depleted mice. The secretion of IFN-gamma and IL-2 was decreased in the regional lymph nodes from Cl2MDP-LIP-treated animals (P<0.05). Furthermore, Cl2MDP-LIP-treated mice had decreased HSV-1 specific proliferative responses (P<0.05) and DTH response after corneal HSV-1 infection (P<0.05). The virus-neutralizing serum-antibody levels (P<0.05) increased while the HSV-1 specific IgG2a/IgG1-ratio was unaffected after macrophage depletion. Macrophage depletion did not induce a shift between the T helper 1 (Th1) and Th2 response in this HSK model. The data suggest that conjunctival macrophage functions are enhancing the T-cell-mediated immune response after corneal infection. This effect is at least in part responsible for the impaired course of herpetic keratitis after macrophage depletion.
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PMID:Conjunctival macrophage-mediated influence of the local and systemic immune response after corneal herpes simplex virus-1 infection. 1222 70

In the retrospective study the authors evaluate clinical results of phototherapeutic keratectomy (PTK) that is one of the alternative methods used in treatment of some of the superficial corneal diseases. The authors present the group of 89 eyes of 63 patients with diagnose: dry spot corneae in 69 eyes (77.5%), recurrent corneal erosion in 13 eyes (14.5%), corneal dystrophy in 2 eyes (1.8%), recurrent herpes simplex keratitis in 3 eyes (2.7%), recurrent pterygium in 2 eyes (1.8%), atopic keratoconjunctivitis with mucous plaque in 1 eye (0.9%). The average age was 45.2 years (14-84 years) and average follow-up period was 29 months (3-52 months). The operation was done with the use of device Keracor 117 (ArF excimer laser) in topical anaesthesia, with the average zone of ablation 4.1 mm and average depth of ablation 24 mu in one go. In ten cases was the operation carried out repeatedly. We evaluated the postoperative complications, postoperative changes of refraction and final the best corrected visual acuity. For low percentage of postoperative complications, decrease or disappearance of subjective difficulties and improvement of visual acuity with minimal stress for the patient we can recommend PTK as save and efficient method in treatment of corneal diseases mentioned above.
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PMID:[Phototherapeutic keratectomy in the treatment of superficial corneal diseases]. 1282 1

To determine the distribution and activities of metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) during the course of experimental herpes simplex virus (HSV) type-1 keratitis, BALB/c mice were corneally infected with 10(5) plaque-forming units (PFU) of HSV-1 (KOS strain) and then observed for the clinical signs of keratitis. Corneas were harvested at days 0, 2, 7 and 14 post-infection (p.i.). MMP-2, MMP-9, MMP-8, TIMP-1 and TIMP-2 were detected by immunohistochemistry and the Western blot technique. The enzymatic activities were analyzed by zymography. Epithelial HSV keratitis was present at day 2 after corneal infection and healed by day 5 p.i. While the expression and activity of MMP-2, MMP-8 and MMP-9 increased in the corneas at day 2 p.i., it was reduced at day 7 p.i. TIMP-1 and -2 were expressed in the corneas before and seven days after infection. Necrotizing stromal keratitis with corneal ulceration and dense polymorphonuclear leukocyte (PMN) infiltration was present at day 14 p.i. This correlated with increased expression of MMP-2, MMP-8 and MMP-9 in the corneas. MMP-8, MMP-9 and MMP-2 staining was particularly intense in the proximity of the ulcers and in areas of PMN infiltration. At day 14 p.i., MMP-2, -8 and -9 activities were upregulated, and TIMP-2 was expressed. These data suggest that MMPs produced by resident corneal cells and PMNs may possibly play a role in early epithelial keratitis and in the ulcerative process in the late phase after corneal HSV-1 infection. The ratio of MMPs to TIMPs may be important for the course of necrotizing HSV keratitis. TIMPs might participate in the repair process.
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PMID:Matrix metalloproteinases (MMP-2 and 9) and tissue inhibitors of matrix metalloproteinases (TIMP-1 and 2) during the course of experimental necrotizing herpetic keratitis. 1287 54

Rapp, Fred (Baylor University College of Medicine, Houston, Tex.). Variants of herpes simplex virus: isolation, characterization, and factors influencing plaque formation. J. Bacteriol. 86:985-991. 1963.-Variants of herpes simplex virus were isolated which differed in plaque size and in virulence for rabbits and mice. Keratitis on the rabbit cornea and generalized disease were associated with the large, but not the small, plaque variants. The large plaque variants were about as neurovirulent as was the parent strain for weanling mice, but the majority of the small plaque variants were only 1% as virulent for mice as was the parent virus. Agar inhibited the formation of plaques by the parent strain and all variants tested; development of plaques was retarded and the number of plaques was approximately 60% less than those developing under an overlay in which methyl cellulose had been substituted for the agar. Rabbit kidney cells and human embryonic lung fibroblasts were more sensitive than mouse embryo fibrolasts to infection with all variants tested.
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PMID:VARIANTS OF HERPES SIMPLEX VIRUS: ISOLATION, CHARACTERIZATION, AND FACTORS INFLUENCING PLAQUE FORMATION. 1408 Aug 11

This article reviews conditions that primarily affect the corneal epithelium as distinct from corneal stromal diseases. Corneal ulceration is discussed elsewhere in this issue. The other corneal conditions include a variety of more subtle epithelial disease,which might colloquially be termed epitheliopathies, as well as uninfected indolent superficial ulcerations, corneal neoplasia, and eosinophilic keratitis. The fungal plaque is an unusual and somewhat chronic form of epithelial infection. Although less common than corneal ulcers, this collection of lesions may present uniquely challenging obstacles to diagnosis and identification of a cure. Newer therapies and surgical strategies are discussed.
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PMID:Corneal epithelial disease. 1527 26

This study aimed to evaluate the efficacy of topical ophthalmic aciclovir applied five times daily as a treatment for feline herpesvirus type 1 (FHV-1) keratitis in a group of cats in a first-opinion practice setting. Cats with ocular signs indicative of FHV-1 or Chlamydophila species infection, predominantly conjunctivitis and keratitis, were tested for FHV-1 antigen using an immunofluorescent technique on air-dried conjunctival swabs. They were first treated with topical chlortetracycline with efficacy against Chlamydophila species and then, in cases positive for FHV-1, with topical aciclovir. The time to recovery was determined and illustrated using a Kaplan-Meier plot. Three cats were infected with Chlamydophila species and showed a median time to recovery of 14 days (95 per cent confidence interval [CI] 10 to 18 days), while 30 cats infected with FHV-1 showed a median time to recovery of 12 days (95 per cent CI 10 to 14 days). The drug dose at which 50 per cent plaque reduction (ED50) occurred in a standard plaque reduction assay was determined in an in vitro study. This showed a mean (SD) ED50 of aciclovir of 25 (3.5) mg/ml compared with 0.4 (0.05) mg/ml for trifluorothymidine, a drug known to be efficacious against FHV-1. The study shows that even though aciclovir is generally considered to lack efficacy against ocular FHV-1 infection, when used frequently it can have a beneficial effect in FHV-1 conjunctivitis and keratitis.
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PMID:Efficacy of topical aciclovir for the treatment of feline herpetic keratitis: results of a prospective clinical trial and data from in vitro investigations. 1612 35

Fumaric acid derivates have been shown to stimulate T helper-2-cytokines (interleukin (IL)-4, -5) without affecting the T-helper-1-cytokine (IL-2, interferon (IFN)-gamma)-response. Herein, the influence of systemic treatment with the fumaric acid derivate dimethylfumarate (DMF) on the secretion of T helper-cytokines and the development of HSV-1 stromal keratitis (HSK) was studied in mice. The corneas from BALB/c mice were infected with 10(5) PFU of HSV-1 (KOS strain). While one group of mice was treated intraperitoneally with PBS, another group of mice received DMF at 15 mg/kg of body weight. Expression of IL-2, -4, -10 and IFN-gamma was analysed in HSV-1 activated lymphocytes by ELISA. The severity of epithelial and stromal herpetic keratitis was investigated clinically. Corneas were studied for the inflammatory cell infiltration, and the CD3-, CD4- and CD8-positive cells were analysed by immunohistochemistry. The IL-2, -4, 10 and IFN-gamma content was measured in the corneas. Virus replication in the eyes was analysed by a plaque-assay. The DTH-response, the HSV-specific T cell proliferation and the serum neutralizing antibody-titres were investigated. DMF increased IL-4 and IL-10, but not IL-2 and IFN-gamma, secretion in activated lymphocytes from the spleen. Incidence and severity of stromal HSV-1 keratitis was reduced in the DMF group (P < 0.01). In the corneas from DMF-treated mice, the numbers of CD3+ and CD4+ cells were decreased and IL-4 was increased. Severity of epithelial disease and the virus-clearance from the eyes did not differ between the PBS and DMF group of mice. DTH, HSV-specific T cell proliferation and the neutralizing antibody-titres were not impaired. DMF increased the T helper-2-cytokine secretion in activated lymphocytes. After corneal HSV-1 infection, corneas from DMF treated mice had increased IL-4 content. This is associated with an improvement of herpetic stromal keratitis and reduced corneal T cell infiltration. DMF did not impair the systemic antiviral response.
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PMID:Improvement of herpetic stromal keratitis with fumaric acid derivate is associated with systemic induction of T helper 2 cytokines. 1617 74

To compare the efficacies of valacyclovir (VCV) and acyclovir (ACV) on murine herpetic epithelial keratitis, mice inoculated with herpes simplex virus type 1(HSV-1) strain McKrae were divided into 6 treatment groups: oral VCV 50 mg/kg and 100 mg/kg, oral ACV 50 mg/kg, ACV eye ointment (EO), ACV eye drops (ED), and placebo. Keratitis scores showed that oral VCV 50 mg/kg, oral ACV, and ACV ED had equivalent efficacies, while oral VCV 100 mg/kg was as efficacious as ACV EO during acute infection. Each treatment group was further divided into the stimulated group with HSV-1 reactivation by immunosuppressant drugs and hyperthermia, and the non-stimulated group without reactivation. We assessed the virus titers in tissues by plaque assay and HSV DNA copy number in the trigeminal ganglia (TG) by real time polymerase chain reaction (PCR). Results showed that the virus titers in the tissues were lowered after reactivation, and the oral VCV group with reactivation had significantly reduced DNA copy number in the TG than the same treatment group without reactivation. In conclusion, oral VCV is as efficacious as ACV EO and significantly suppresses HSV-1 reactivation.
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PMID:Effects of anti herpetic drugs on mice with herpetic epithelial keratitis after reactivation of herpes simplex virus type 1. 1858 62


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