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

Although Acanthamoeba keratitis has been recognized as one of the important infectious diseases of the cornea, especially in contact lens wearers in recent years, its taxonomy has not been well established. We carried out mitochondrial DNA (mtDNA) analysis of the Acanthamoeba organisms isolated from corneal lesions in four eyes of three patients who had suffered from keratitis. The mtDNA was analyzed by restriction fragment length polymorphism (RFLP) using restriction enzymes Bg/II and EcoRI. The RFLP analyses revealed that the DNA phenotypes of the Acanthamoeba organisms were identical to those of the Ma strain in two patients and to the Castellani strain in one patient.
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PMID:Restriction enzyme analysis of mitochondrial DNA of Acanthamoeba strains isolated from corneal lesions. 950 61

Reverse transcription polymerase chain reaction (RT-PCR) was applied in the detection of herpes simplex virus-1 (HSV-1) mRNA from tear film and corneal epithelium in a murine herpetic keratitis model. The diagnostic value of this new technique for acute herpetic keratitis was evaluated in comparison with direct PCR for genomic DNA and viral culture. On day 2 postinfection (PI) of HSV, all mice showed dendritic keratitis, and PCR, RT-PCR, and viral culture were positive in all samples. On day 8 PI, no dendritic keratitis was observed in any mouse, PCR was positive in all samples, while RT-PCR was positive in only 5 of 12 samples and viral culture in only 2 of 12. The sensitivity of RT-PCR was lower than that of PCR, and approximately the same as viral culture; however, the findings of RT-PCR more closely concurred with clinical observations than the findings of PCR. These results show the potential of RT-PCR for rapid, specific diagnosis of acute herpetic keratitis.
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PMID:Detection of HSV mRNA using reverse transcription-polymerase chain reaction for diagnosis in murine herpetic keratitis model. 950 59

To assess the current epidemiologic status of onchocerciasis in Colombia two surveys were undertaken in 1995 in a suspected new focus on the border between Colombia and Ecuador and in the known focus located on the Micay River. No new focus was found along the Colombia-Ecuador border. In the known focus, communities along the upper Micay River and its tributaries were surveyed; 655 adults underwent physical examinations and skin biopsies. Infected individuals were found almost exclusively in the community of Naiciona, where prevalence of infection was 40% (36 of 91). Polymerase chain reaction detection of onchocercal DNA in skin snips correlated with the skin-snip biopsy results. The prevalence of punctate keratitis, the only ocular manifestation found, was 33%. A rapid entomologic assessment demonstrated Simulium exiguum infected with Onchocerca volvulus. This is the first finding in Colombia of naturally infected black flies and confirms S. exiguum as a vector species. These data will be used for implementing a control program using periodic ivermectin distribution.
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PMID:Current status of onchocerciasis in Colombia. 959 47

In the tissues of the herpes-infected eye of a rabbit the content of adenosine triphosphoric acid (ATP), glucose and pyroracemic acid decreases and the level of lactic acid rises, i.e. anaerobic glycolysis prevails over the aerobic decomposition of glucose. A sharp decrease in the amount of ATP in the cornea and the iris in herpetic keratitis is due to the increased consumption of ATP for the synthesis of DNA and polypeptides of herpes simplex virus, as well as to disturbances in the oxidation transformations of glucose linked with the increased proportion of anaerobic glycolysis.
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PMID:[Glycolytic metabolites and adenosine triphosphoric acid in the herpes-infected eye]. 966 12

PAX6 is a transcription factor with two DNA-binding domains (paired box and homeobox) and a proline-serine-threonine (PST)-rich transactivation domain. PAX6 regulates eye development in animals ranging from jellyfish to Drosophila to humans. Heterozygous mutations in the human PAX6 gene result in various phenotypes, including aniridia, Peter's anomaly, autosomal dominant keratitis, and familial foveal dysplasia. It is believed that the mutated allele of PAX6 produces an inactive protein and aniridia is caused due to genetic haploinsufficiency. However, several truncation mutations have been found to occur in the C-terminal half of PAX6 in patients with Aniridia resulting in mutant proteins that retain the DNA-binding domains but have lost most of the transactivation domain. It is not clear whether such mutants really behave as loss-of-function mutants as predicted by haploinsufficiency. Contrary to this theory, our data showed that these mutants are dominant-negative in transient transfection assays when they are coexpressed with wild-type PAX6. We found that the dominant-negative effects result from the enhanced DNA binding ability of these mutants. Kinetic studies of binding and dissociation revealed that various truncation mutants have 3-5-fold higher affinity to various DNA-binding sites when compared with the wild-type PAX6. These results provide a new insight into the role of mutant PAX6 in causing aniridia.
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PMID:Truncation mutations in the transactivation region of PAX6 result in dominant-negative mutants. 970 83

Herpes simplex virus type 1 (HSV-1) causes chronic blepharitis and conjunctivitis as well as keratitis in humans. The pathogenesis of these inflammatory ocular and dermal lesions is not well understood. We have examined the persistence of HSV-1 DNA and its relationship to inflammatory lesions in the conjunctiva and eyelid skin of mice which were inoculated with HSV-1 by the corneal route. Viral DNA was detected by in situ PCR in the conjunctiva and eyelid tissue of infected mice at 5, 11, 23, and 37 days postinfection (p.i.). This DNA was localized in the epithelial cells of the conjunctiva and hair follicles and in the epidermal cells of the eyelid skin. Viral proteins were not detected in the conjunctiva or the eyelid skin after 5 days p.i., even though histopathological lesions were found at 23 and 37 days p.i. in both tissues. The DNA-containing cells were adjacent to sites of inflammation in the chronic lesions in both the conjunctiva and the eyelid skin. A similar temporal and spatial relationship between HSV-1 DNA and inflammatory lesions has been previously reported for the cornea. Our data suggest that the lesions in the cornea, conjunctiva, and eyelid skin progress similarly. Further studies are required to determine whether the long-term presence of HSV-1 is involved in the mechanism by which these chronic inflammatory lesions develop. The presence of HSV-1 DNA in these extraocular tissues for extended periods may constitute persistent viral infection of nonneuronal cells.
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PMID:Persistence of herpes simplex virus type 1 DNA in chronic conjunctival and eyelid lesions of mice. 976 63

The identification of pathogens in patients with bacterial keratitis remains problematic because standard diagnostic tests are negative for 40 to 60% of patients. A cross-sectional study was undertaken to determine if PCR and sequence analysis of 16S ribosomal DNA (rDNA) could be used to detect bacterial pathogens in patients with keratitis. Corneal specimens were collected for culture and rDNA typing. Variable segments of each rDNA specimen were amplified by PCR, sequenced, and aligned with the sequences in GenBank. Eleven patients had microbiologically documented bacterial keratitis, while 17 patients had keratitis due to other causes. Nine (82%) of 11 bacterial keratitis patients were PCR positive; each sequencing result matched the culture results. Seventeen (100%) patients with nonbacterial keratitis were PCR negative. Our data suggest that 16S rDNA typing holds promise as a rapid alternative to culture for identifying pathogens in patients with bacterial keratitis.
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PMID:16S ribosomal DNA typing for identification of pathogens in patients with bacterial keratitis. 981 60

HIV infection destroying cellular immunity system creates prerequisites for herpesvirus involvement of the anterior and posterior segments of the eye. A total of 370 HIV-infected patients were examined. Ocular diseases were detected in 53 (14.35%). The most prevalent conditions were retinal angiopathy (most often with cotton-like foci--in 7.3% and cytomegalovirus (CMV) retinitis in 4.1%). Cotton-like foci in the presence of CMV activation (evidenced by high level of CMV DNA in peripheral blood) are a sign of probable CMV infection manifesting by retinitis or involvement of other organs. Intravenous gancyclovir in a dose of 7.5 mg/kg twice a day and its combination with interferon inductor poludan are effective methods for therapy of CMV infection, preventing blindness or poor vision. Moreover, combination of chemotherapy with interferon inductors cured involvement of the anterior segment of the eye--herpetic keratitis and iridocyclitis, which sometimes develop in the presence of HIV infection.
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PMID:[Viral lesions of the eye in human immunodeficiency virus infection]. 986 83

The modern local antibiotics, such as the aminoglycosides and quinolones, are very successful in treating infectious conjunctivitis and keratitis. More notably in some Third World countries, however, suppurative keratitis is found in more than half of the infectious disease cases caused by Fusarium species. Here, of course, treatment should be antifungal. The emergence of some problematic microorganisms is related to contact lens wear. Pseudomonas, for example, have the ability to adhere to contact lenses and thus form microcolonies, which are protected by biofilm that predisposes to infection. Acanthamoeba infections of the cornea are a direct consequence of inappropriate or inadequate disinfection of contact lens systems. Occasionally the diagnosis of herpes simplex manifestations of the outer eye can be very difficult. Even more confusing is the delayed appearance of zoster manifestations, such as pseudodendrites, particularly in cases of zoster sine herpete eruptione. The polymerase chain reaction is of particular value in demonstrating the presence of varicella zoster DNA. Although infectious disease of the outer eye remains common, the incidence and complications have increased because of frequent use of antimicrobial agents. In the under-developed areas of the world, however, infections are still very common, are frequently caused by fungi, and are the cause of serious ocular complications. In the Western World infectious eye disease does not seem to be a major diagnostic or therapeutic point at present. Some organisms that have been in the environment all along, however, have emerged in the past half century as a major problem. Thus, in the past years a number of new techniques in diagnosis as well as new insights in pathophysiology and new developments in treatment have emerged that are of interest.
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PMID:Infectious diseases of the conjunctiva and cornea. 1016 42

The genus Acanthamoeba comprises free-living amebae identified as opportunistic pathogens of humans and other animal species. Morphological, biochemical and molecular approaches have shown wide genetic diversity within the genus. In an attempt to determine the genetic relatedness among isolates of Acanthamoeba we analyzed randomly amplified polymorphic DNA (RAPD) profiles of 11 Brazilian isolates from cases of human keratitis and 8 American type culture collection (ATCC) reference strains. We found that ATCC strains belonging to the same species present polymorphic RAPD profiles whereas strains of different species show very similar profiles. Although most Brazilian isolates could not be assigned with certainty to any of the reference species, they could be clustered according to pattern similarities. The results show that RAPD analysis is a useful tool for the rapid characterization of new isolates and the assessment of genetic relatedness of Acanthamoeba spp. A comparison between RAPD analyses and morphological characteristics of cyst stages is also discussed.
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PMID:Random amplified polymorphic DNA profiles as a tool for the characterization of Brazilian keratitis isolates of the genus Acanthamoeba. 1062 70


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