Insights into the molecular pathogenesis of ocular tuberculosis.

Unclear pathogenic mechanisms underlying the ocular tuberculosis (OTB) has resulted in perplexity related to the diagnosis and management of the disease. Developments in experimental research and innovations in molecular diagnostics have recently provided a new understanding of disease pathogenesis and natural history. The current review focuses on the new insights into OTB pathogenesis, derived from in vivo and in vitro studies on Mycobacterium tuberculosis dissemination and localization into the eye, in combination with histopathological studies on chorioretinal tissue and vascular network. Advances in the knowledge of OTB have influenced disease management in the clinical setting and lead to reconsideration of the role of existing treatments and suggesting potential new therapeutic approaches.

Ocular Autoimmune Systemic Inflammatory Infectious Study (OASIS) - Report 2: Pattern of Uveitis Investigations in Singapore.

Purpose: To analyze the pattern of laboratory investigations of uveitis at a tertiary referral eye care center in Singapore.Methods: Retrospective analysis of 2040 uveitis cases from the Ocular Autoimmune Systemic Inflammatory Infectious Study (OASIS) database over a 12-year period (2004 - 2015).Results: Patients with retinal vasculitis (RV) had the most tests utilized per patient (6.79), followed by intermediate uveitis (IU) (5.25), panuveitis (Pan) (5.12), posterior uveitis (PU) (4.17), anterior uveitis (AU) (2.75), and keratouveitis (KU) (1.10). The most frequently utilized test for infective etiology were the VDRL (41.3%), Syphilis IgG (29.5%), and T-SPOT.TB (24.6%). For autoimmune tests, ANA was most utilized (18.2%), followed by anti-dsDNA (14.8%), and HLA-B27 (12.4%).Conclusion: There was high utilization of autoimmune tests such as ANA, anti-dsDNA, RF, and ANCA, despite its limited yield. Rationalization of investigations in patients with ocular inflammation via a stepladder approach may help optimize the use of limited resources.

Ocular Syphilis: An Update.

This review aims to provide an update on the clinical presentation, diagnosis, and treatment of ocular syphilis. While ocular syphilis is not a new phenomenon, recent resurgence in the incidence of overall syphilis, particularly among HIV-positive individuals, has sparked a new interest in an old disease. The challenge of ocular syphilis is manifold: firstly, it manifests in a spectrum of ways that can occur at any stage of the disease, with the most common finding being panuveitis. It may occur as early as 6 weeks after transmission and may be the only presenting feature of systemic syphilis; secondly, the relationship between HIV and syphilis has been established, as primary syphilis facilitates HIV transmission and HIV may modify the natural course of syphilis, increasing the propensity of the disease to progress to neurosyphilis. The authors present the latest updates to the changing landscape of ocular syphilis.

Ocular Autoimmune Systemic Inflammatory Infectious Study (OASIS) - Report 1: Epidemiology and Classification.

PURPOSE: To report the epidemiology and classification of ocular inflammation at a tertiary eye care center in Singapore. METHODS: Retrospective cohort study of the clinical records of consecutive new cases from the Ocular Autoimmune Systemic Inflammatory Infectious Study (OASIS) database from 2004-2015. RESULTS: A total of 2200 patients were studied from the OASIS database. The most common anatomic diagnosis was anterior uveitis (55.9%), posterior uveitis (17.5%), panuveitis (9.6%), and intermediate uveitis (4.7%). In addition, scleritis (6.1%), keratouveitis (2.8%), retinal vasculitis (2.2%), and episcleritis (1.2%) were observed. Etiology was established in 65.1%, with 35.2% of patients associated with non-infectious etiologies. The most common etiologies found were presumed tuberculosis (7.2%), followed by cytomegalovirus infection (6.9%), herpetic infection (6.3%), HLA-B27-associated anterior uveitis (4.2%), and ankylosing spondylitis (3.8%). CONCLUSIONS: The pattern of ocular inflammation in Singapore has similarities with both Western and Asian populations. Anterior uveitis was the most common, with non-infectious etiologies being slightly more common than infectious etiologies.

Retrotransposons Are the Major Contributors to the Expansion of the Drosophila ananassae Muller F Element.

The discordance between genome size and the complexity of eukaryotes can partly be attributed to differences in repeat density. The Muller F element (∼5.2 Mb) is the smallest chromosome in Drosophila melanogaster, but it is substantially larger (>18.7 Mb) in D. ananassae To identify the major contributors to the expansion of the F element and to assess their impact, we improved the genome sequence and annotated the genes in a 1.4-Mb region of the D. ananassae F element, and a 1.7-Mb region from the D element for comparison. We find that transposons (particularly LTR and LINE retrotransposons) are major contributors to this expansion (78.6%), while Wolbachia sequences integrated into the D. ananassae genome are minor contributors (0.02%). Both D. melanogaster and D. ananassae F-element genes exhibit distinct characteristics compared to D-element genes (e.g., larger coding spans, larger introns, more coding exons, and lower codon bias), but these differences are exaggerated in D. ananassae Compared to D. melanogaster, the codon bias observed in D. ananassae F-element genes can primarily be attributed to mutational biases instead of selection. The 5' ends of F-element genes in both species are enriched in dimethylation of lysine 4 on histone 3 (H3K4me2), while the coding spans are enriched in H3K9me2. Despite differences in repeat density and gene characteristics, D. ananassae F-element genes show a similar range of expression levels compared to genes in euchromatic domains. This study improves our understanding of how transposons can affect genome size and how genes can function within highly repetitive domains.