Eales' disease, first described by the British ophthalmologist Henry Eales in 1880, is characterized by three overlapping stages of venous inflammation (vasculitis), occlusion, and retinal neovascularization. Diagnosis is mostly clinical and requires exclusion of other systemic or ocular conditions that could present with similar retinal features. In recent years, immunological, molecular biological, and biochemical studies have indicated the role of human leukocyte antigen, retinal autoimmunity, Mycobacterium tuberculosis genome, and free radical-mediated damage in the etiopathogenesis of this disease. However, its etiology appears to be multifactorial. The management depends on the stage of the disease and consists of medical treatment with oral corticosteroids in the active inflammatory stage and laser photocoagulation in the advanced retinal ischemia and neovascularization stages.
A clinical suspicion of infection by RGNTM in delayed-onset postoperative endophthalmitis should be considered when resistance to standard therapy is encountered.
Purpose:
To standardize a novel duplex polymerase chain reaction (PCR) targeting 18S rRNA gene and internal transcribed spacer region for the identification of Pythium insidiosum isolates and also to detect P. insidiosum genome directly from corneal specimens of patients with suspected ocular pythiosis.
Methods:
A total of 42 nonsporulating molds culturally and morphologically resembling suspected unidentified fungal isolates (corneal buttons 33 and corneal scrapings 9) and 14 clinical specimens (corneal buttons 7 and corneal scrapings 7) clinically suspected to be ocular pythiosis were included in the present study. Standardization of uniplex PCRs and duplex PCRs targeting 18S rRNA gene and internal transcribed spacer region and further application of the standardized PCRs on both clinical isolates and clinical specimens suspected to have fungal keratitis. The sensitivity and specificity of the standardized duplex PCR were calculated using Medcal.net software.
Results:
The standardized uniplex and duplex PCRs were found specific for the detection of only P. insidiosum DNA, and the analytical sensitivities of the primers were 1.36 Zg. Of the 14 clinical specimens analyzed, 13 were positive in both corneal specimens and their respective P. insidiosum isolates. The specificity of the novel duplex PCR was 100% when applied on corneal specimens and clinical isolates, but the sensitivity was 92.8% (13/14) and 100% (42/42), respectively, for the clinical specimens and fungal isolates from suspected ocular pythiosis patients included in the study.
Conclusions:
The novel duplex PCR developed in this study will aid in rapid identification of P. insidiosum clinical isolates and clinical specimens from suspected ocular pythiosis specimens, which in turn will help the ophthalmologists to initiate appropriate treatment.
Background:
Dengue fever is the most prevalent form of flavivirus infection in humans. We have investigated whether corneoscleral tissue of the donor affected by dengue virus (DENV) harbors the virus.
Purpose:
To identify the risk for viral transmission through corneal transplants in areas where DENV circulates.
Methods:
Excised corneoscleral tissue from a cadaver with a history of viral hemorrhagic fever was analyzed using reverse transcriptase-polymerase chain reaction for the presence of DENV and chikungunya virus (CHIV).
Results:
DENV was detected in RNA extracted from the donor corneoscleral rim. Further genotyping of the viral isolate from the virus-infected cell harvest revealed DENV type 3 as the causative agent. CHIV was not detected.
Conclusions:
The data presented in this study recommend the implementation of polymerase chain reaction for detection of DENV and CHIV to analyze excised corneoscleral tissue of a donor with viral hemorrhagic fever.
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