Total Anterior Staphyloma Secondary to Acanthamoeba Keratitis.

ABSTRACT: There are very few published cases of total anterior staphyloma, all of which have been reported as secondary to fungal keratitis. This study reports the clinical and histopathological findings and subsequent management of a 27-year-old healthy female patient who developed total anterior staphyloma after poor compliance with treatment for clinically diagnosed acanthamoeba keratitis. She underwent a successful evisceration with good long-term results. This case highlights that total anterior staphyloma may also result from untreated keratitis which is not fungal in origin. In cases of fungal and acanthamoeba keratitis, patient compliance with both treatment and follow-up is paramount to avoid vision-threatening sequelae that present significant challenges in their management.

Role of Temporal artery biopsy in a sequential Giant Cell Arteritis fast-track pathway: a 5-year prospective study.

BACKGROUND: Increasing number of centres are establishing sequential fast track pathways (FTP) for management of giant cell arteritis (GCA), with temporal artery ultrasound (US) replacing temporal artery biopsy (TAB) as the first investigational method. Biopsy is performed as second investigation, when US is negative/inconclusive. This study investigates the role of TAB in a sequential GCA-FTP and its utility in those with negative/inconclusive US. METHODS: Prospective study of patients referred for TAB as part of Coventry sequential GCA-FTP May 2014-June 2019. Analysis included sensitivity and specificity of TAB, impact of arterial specimen length and duration of treatment with corticosteroids on sensitivity of TAB and the clinical predictors for a positive biopsy. RESULTS: A total of 1149 patients with suspected GCA were referred to this GCA-FTP, with 109 (9.5%) referred for TAB. Overall sensitivity of TAB was 47% (specificity: 100%) and in patients with negative/inconclusive US sensitivity was 39% (specificity:100%). Post-fixation arterial specimen length <15 mm showed lower sensitivity (14%), which increased to 52% when specimen length was ≥15 mm. Sensitivity of TAB was highest in first 7 (60%) to 10 days (59%) from starting corticosteroids. Predictors of positive biopsy using univariate logistic regression analysis were jaw claudication (OR = 5.40; p = 0.0057), elevated erythrocyte sedimentation rate (OR = 5.50; p = 0.013) and elevated C-reactive protein (OR = 23.7; p = 0.0043). CONCLUSION: This is the first study to look at the role of TAB in a sequential GCA-FTP. Biopsy plays an important role in GCA-FTP, when US is negative/inconclusive. Sensitivity of TAB improved when specimen length was ≥15 mm and performed within 10 days of commencing corticosteroids.

CO2-dependent opening of connexin 26 and related ß connexins.

We have previously shown connexin mediated CO(2)-dependent ATP release from the surface of the medulla oblongata. Given the localization of connexin 26 (Cx26) to the chemosensing areas of the medulla, we have tested in a heterologous expression system (HeLa cells) whether Cx26 may be sensitive to changes in PCO2. Cx26 responded to an increase in PCO2 at constant extracellular pH by opening and to a decrease in PCO2 by closing. Furthermore, Cx26 was partially activated at a physiological PCO2 of around 40 mmHg. Cx26 in isolated patches responded to changes in PCO2, suggesting direct CO(2) sensitivity of the hemichannel to CO(2). Heterologous expression of Cx26 in HeLa cells was sufficient to endow them with the capacity to release ATP in a CO(2)-sensitive manner. We have examined other heterologously expressed connexins for their ability to respond to changes in PCO2. The closely related ß connexins Cx30 and Cx32 also displayed sensitivity to changes in PCO2, but with slightly different characteristics from Cx26. The more distant Cx43 exhibited CO(2)-dependent closing (possibly mediated through intracellular acidification), while Cx36 displayed no CO(2) sensitivity. These surprising findings suggest that connexins may play a hitherto unappreciated variety of signalling roles, and that Cx26 and related ß connexins may impart direct sensitivity to CO(2) throughout the brain.