Comparison of two different optical coherence tomography angiography devices in detecting healthy versus glaucomatous eyes - an observational cross-sectional study.

BACKGROUND: To understand the differences between two different optical coherence tomography angiography (OCTA) devices in detecting glaucomatous from healthy eyes by comparing their vascular parameters, diagnostic accuracy and test-retest reliability. METHODS: A cross-sectional observational study was performed on healthy and glaucoma subjects, on whom two sets of OCTA images of optic disc and macula were acquired using both AngioVue (Optovue, USA) and Swept Source (Topcon, Japan) OCTA devices during one visit. A novel in-house software was used to calculate the vessel densities. Diagnostic accuracy of the machines in differentiating healthy versus glaucomatous eyes was determined using area under the receiver operating characteristic curve (AUROC) and test-retest repeatability of the machines was also evaluated. RESULTS: A total of 80 healthy and 38 glaucomatous eyes were evaluated. Glaucomatous eyes had reduced mean vessel density compared to healthy controls in all segmented layers of the optic disc and macula using AngioVue (p ≤ 0.001). However, glaucomatous eyes had higher mean vessel density on optic disc scans using Swept Source, with lack of statistically significant difference between healthy and glaucomatous eyes. The AUROC showed better diagnostic accuracy of AngioVue (0.761-1.000) compared to Swept Source (0.113-0.644). The test-retest reliability indices were generally better using AngioVue than Swept Source. CONCLUSIONS: AngioVue showed better diagnostic capability and test-retest reliability compared to Swept Source. Further studies need to be undertaken to evaluate if there is any significant difference between the various machines in diagnosing and monitoring glaucoma.

Identification of amino acid residues essential for catalytic activity of gentisate 1,2-dioxygenase from Pseudomonas alcaligenes NCIB 9867.

Gentisate 1,2-dioxygenase (GDO, EC 1.13.11.4) is a ring cleavage enzyme that utilizes gentisate as a substrate yielding maleylpyruvate as the ring fission product. Mutant GDOs were generated by both random mutagenesis and site-directed mutagenesis of the gene cloned from Pseudomonas alcaligenes NCIB 9867. Alignment of known GDO sequences indicated the presence of a conserved central core region. Mutations generated within this central core resulted in the complete loss of enzyme activity whereas mutations in the flanking regions yielded GDOs with enzyme activities that were reduced by up to 78%. Site-directed mutagenesis was also performed on a pair of highly conserved HRH and HXH motifs found within this core region. Conversion of these His residues to Asp resulted in the complete loss of catalytic activity. Mutagenesis within the core region could have affected quaternary structure formation as well as cofactor binding. A mutant enzyme with increased catalytic activities was also characterized.

Development of a patient specific artificial tracheal prosthesis: design, mechanical behavior analysis and manufacturing.

There is a need to create patient specific organ replacements as there are differences in the anatomical dimensions among individuals. High failure rates in tracheal prosthesis are attributed to the lack of mechanical strength and flexibility, slow rate of growth of ciliated epithelium and leakage of interstitial fluid into the lumen. This paper proposes a methodology of design, simulations and fabrication of a patient specific artificial tracheal prosthesis for implantation to closely mimic the biomechanical properties of the natural trachea, and describes the prototype device and its materials. Results show that the patient-specific trachea prosthesis has mechanical properties approximate that of normal tracheal rings. The user centric tracheal prosthesis is demonstrated to be a promising candidate for tracheal replacement.

Outcome of off-pump coronary artery bypass in renal dialysis patients.

BACKGROUND: Renal dialysis patients are a subgroup at major operative risk when undergoing coronary artery bypass grafting (CABG). Even though CABG without cardiopulmonary bypass (CPB) has decreased the surgical risk and provided good short-term results, the long-term survival seems uncertain. We report here on the long-term outcome of CABG without CPB in renal dialysis patients. METHODS: From 1998 to 2002, 44 renal dialysis patients underwent elective CABG without CPB, including 17 minimally invasive direct coronary artery bypass (MIDCAB) and 27 off-pump CABG (OPCAB) procedures. There were 5 one-vessel, 12 two-vessel and 27 multi-vessel coronary artery disease patients, who mainly had left internal thoracic artery (LITA) to left anterior descending coronary artery (LAD) grafting with an additional saphenous vein graft to non-LAD coronaries. RESULTS: All 44 patients were followed up for 44.4 +/- 31.2 months. Three (6.8 %) surgical deaths within 30 days occurred and 25 late mortalities happened over a period of 2 - 79 months. The 5-year cumulative rate of total survival is 38.2 % and the freedom from cardiac death is 70.9 %. Using hazard analysis, old age (> 60 years) and incomplete coronary revascularization was found to significantly affect the total survival. CONCLUSIONS: CABG without CPB provided an acceptable surgical mortality and morbidity. The high incidence of non-cardiac death associated with dialysis complications had an adverse impact on the overall outcome. The LITA bypass operation method combined with intensive care for dialysis complications would hopefully fulfill the goal to improve the short- and long-term results in this subgroup.

Iris metastasis: an unusual cause of anterior uveitis.

We report a case of anterior uveitis due to iris metastasis in a patient with known carcinomatosis.