Deep learning segmentation of hyperautofluorescent fleck lesions in Stargardt disease.

Stargardt disease is one of the most common forms of inherited retinal disease and leads to permanent vision loss. A diagnostic feature of the disease is retinal flecks, which appear hyperautofluorescent in fundus autofluorescence (FAF) imaging. The size and number of these flecks increase with disease progression. Manual segmentation of flecks allows monitoring of disease, but is time-consuming. Herein, we have developed and validated a deep learning approach for segmenting these Stargardt flecks (1750 training and 100 validation FAF patches from 37 eyes with Stargardt disease). Testing was done in 10 separate Stargardt FAF images and we observed a good overall agreement between manual and deep learning in both fleck count and fleck area. Longitudinal data were available in both eyes from 6 patients (average total follow-up time 4.2 years), with both manual and deep learning segmentation performed on all (n = 82) images. Both methods detected a similar upward trend in fleck number and area over time. In conclusion, we demonstrated the feasibility of utilizing deep learning to segment and quantify FAF lesions, laying the foundation for future studies using fleck parameters as a trial endpoint.

Sensory experience-dependent formation of perineuronal nets and expression of Cat-315 immunoreactive components in the mouse somatosensory cortex.

Perineuronal nets (PNNs) are structures of extracellular matrix molecules surrounding the cell bodies and proximal dendrites of certain neurons. While PNNs are present throughout the mouse cerebral cortex, recent studies have shown that the components differ among cortical sub-regions and layers, suggesting region-specific functions. Parvalbumin-expressing interneurons (PV neurons) may be important regulators of cortical plasticity during the early "critical period" that is sensitive to sensory input. Here we examined the distribution and developmental functions of PNN components associated with PV neurons in the somatosensory cortex during the critical period. Aggrecan, brevican, neurocan, phosphacan, and tenascin-R were identified as PNN components in the mouse somatosensory cortex. High-magnification analysis revealed that some lectin Wisteria floribunda agglutinin (WFA)-reactive molecules did not co-localize with monoclonal antibody Cat-315 recognition molecules around the cell body. During postnatal development, Cat-315-positive (Cat-315+) PNNs appeared later than PNNs binding to the lectin WFA (WFA+ PNNs). These WFA+ PNNs changed from granular-like to reticular-like structures during normal cortical development, while this transition was delayed by sensory deprivation. This study indicates that the formation of reticular-like WFA+ PNNs is dependent on sensory experience in the mouse somatosensory cortex. We suggest that Cat-315+ molecules and WFA expression in PNNs are involved in the early critical period of input-dependent cortical plasticity.

Effect of ultrasonic ZnPO-4 cement removal on band adhesion and cement solubility under orthodontic bands.

The use of ultrasonic energy to remove excess ZnPO-4 cement from orthodontic bands reduces the solubility of the cement but does not affect band adhesion unless excessive band contact is made. Excessive band contact weakens band-to-tooth adhesion. The solubility of the cement is increased by decreasing the pH and is increased when organic anions capable of binding metal ions are present.