[OCT-Angiography in diabetic maculopathy : Comparison between microaneurysms and the foveal avascular zone with flourescein angiography]. / OCT-Angiographie bei der diabetischen Maculopathie : Vergleich von Mikroaneurysmata und der foveolären avaskulären Zone mit der Fluoreszeinangiographie.

BACKGROUND: Optical coherence tomography angiography allows an exact visualization of retinal vascular changes. To interpret the possibilities and limitations using OCTA in clinical practice, we analysed the quality of OCTA findings concerning the evaluability. Furthermore, we correlated our OCTA findings with fluorescein angiography (FAG) in relation of the presence of microaneurysms (MA) and enlargement of the foveal avascular zone (FAZ) in diabetic maculopathy. PATIENTS AND METHODS: 30 eyes from 15 patients with diabetic maculopathy were imaged in 3 × 3mm volume scans and were depicted in OCTA mode (SSADA algorithm). By using the automatic segmentation we analysed the vascular changes in the superficial and deep capillary plexus and classified them concerning their qualitative evaluability. We analysed the number of MA in OCTA and fluorescein angiography and correlated them using an overlay technique. We analysed the presence of MA in the superficial and deep capillary plexus in OCTA as well. Furthermore we measured the enlargement of the foveal zone with both methods. RESULTS: In a large number of eyes we could not identifiy MA or measure the enlargement of the FAZ because of poor OCTA or FA quality. In the morphological analysis of our findings we identified a comparable number of MA in both methods, although the localization of the MA was different in both methods in a large number of eyes. The majority of MA was located in the deep capillary plexus. The extension of the foveal avascular zone measured in FA revealed a good correlation to the automatically measured "nonflow area" in the OCTA. CONCLUSION: OCTA allows a good visualization of characteristic vascular changes in diabetic maculopathy. In spite of technical limitations OCTA generates a three-dimensional visualisation of avascular changes. The majority of microaneurysms detected by OCTA showed a corresponding finding in FA. The central avascular zone (FAZ) in OCTA correlates well with the findings from FA. OCTA represents an important additional diagnostic tool to interpret vascular changes in DM.

Hydrogen peroxide is involved in the sclerotial differentiation of filamentous phytopathogenic fungi.

AIMS: The purpose of this study was to investigate the role of H(2) O(2) and the related oxidative stress markers catalase (CAT) and lipid peroxidation in the sclerotial differentiation of the phytopathogenic filamentous fungi Sclerotium rolfsii, Sclerotinia minor, Sclerotinia sclerotiorum and Rhizoctonia solani. METHODS AND RESULTS: Using the H(2) O(2) -specific scopoletin fluorometric assay and the CAT-dependent H(2) O(2) consumption assays, it was found that the production rate of intra/extracellular H(2) O(2) and CAT levels in the sclerotiogenic fungi were significantly higher and lower, respectively, than those of their nondifferentiating counterpart strains. They peaked in the transition between the undifferentiated and the differentiated state of the sclerotiogenic strains, suggesting both a cell proliferative and differentiative role. In addition, the indirect indicator of oxidative stress, lipid peroxidation, was substantially decreased in the nondifferentiating strains. CONCLUSIONS: These findings suggest that the differentiative role of H(2) O(2) is expressed via induction of higher oxidative stress in the sclerotiogenic filamentous phytopathogenic fungi. SIGNIFICANCE AND IMPACT OF THE STUDY: This study shows that the direct marker of oxidative stress H(2) O(2) is involved in the sclerotial differentiation of the phytopathogenic filamentous fungi S. rolfsii, S. minor, S. sclerotiorum and R. solani, which could have potential biotechnological implications in terms of developing antifungal strategies by regulating intracellular H(2) O(2) levels.