Glutathione-Depleting Nanoenzyme and Glucose Oxidase Combination for Hypoxia Modulation and Radiotherapy Enhancement.

Nanoenzymes perceive the properties of enzyme-like catalytic activity, thereby offering significant cancer therapy potential. In this study, Fe3 O4 @MnO2 , a magnetic field (MF) targeting nanoenzyme with a core-shell structure, is synthesized and applied to radiation enhancement with using glucose oxidase (GOX) for combination therapy. The glucose is oxidized by the GOX to produce excess H2 O2 in an acidic extracellular microenvironment, following which the MnO2 shell reacts with H2 O2 to generate O2 and overcome hypoxia. Concurrently, intracellular glutathione (GSH)-which limits the effects of radiotherapy (RT)-can be oxidized by the MnO2 shell while the latter is reduced to Mn2+ for T1 -weighed MRI. The core Fe3 O4 , with its good magnetic targeting ability, can be utilized for T2 -weighed MRI. In summary, the work demonstrates that Fe3 O4 @MnO2 , as a dual T1 - and T2 -weighed MRI contrast agent with strong biocompatibility, exhibits striking potential for radiation enhancement under magnetic targeting.

Using Deep Convolutional Neural Networks for Neonatal Brain Image Segmentation.

INTRODUCTION: Deep learning neural networks are especially potent at dealing with structured data, such as images and volumes. Both modified LiviaNET and HyperDense-Net performed well at a prior competition segmenting 6-month-old infant magnetic resonance images, but neonatal cerebral tissue type identification is challenging given its uniquely inverted tissue contrasts. The current study aims to evaluate the two architectures to segment neonatal brain tissue types at term equivalent age. METHODS: Both networks were retrained over 24 pairs of neonatal T1 and T2 data from the Developing Human Connectome Project public data set and validated on another eight pairs against ground truth. We then reported the best-performing model from training and its performance by computing the Dice similarity coefficient (DSC) for each tissue type against eight test subjects. RESULTS: During the testing phase, among the segmentation approaches tested, the dual-modality HyperDense-Net achieved the best statistically significantly test mean DSC values, obtaining 0.94/0.95/0.92 for the tissue types and took 80 h to train and 10 min to segment, including preprocessing. The single-modality LiviaNET was better at processing T2-weighted images than processing T1-weighted images across all tissue types, achieving mean DSC values of 0.90/0.90/0.88 for gray matter, white matter, and cerebrospinal fluid, respectively, while requiring 30 h to train and 8 min to segment each brain, including preprocessing. DISCUSSION: Our evaluation demonstrates that both neural networks can segment neonatal brains, achieving previously reported performance. Both networks will be continuously retrained over an increasingly larger repertoire of neonatal brain data and be made available through the Canadian Neonatal Brain Platform to better serve the neonatal brain imaging research community.

Analysis of the Correlation Between Cerebrospinal Fluid Space and Outcomes of Anterior Controllable Antedisplacement and Fusion for Cervical Myelopathy Due to Ossification of the Posterior Longitudinal Ligament.

OBJECTIVE: We investigated whether the cerebrospinal fluid (CSF) space on magnetic resonance imaging (MRI) correlates with the outcomes of anterior controllable antedisplacement and fusion (ACAF) for ossification of the posterior longitudinal ligament (OPLL). METHODS: A total of 53 patients with OPLL who had undergone ACAF were enrolled. The Japanese Orthopaedic Association (JOA) scale, visual analog scale, and neck disability index were used to evaluate the clinical outcomes. The area of CSF space and spinal cord on T2-weighted MRI, the occupying rate of the CSF space and spinal cord, and the postoperative MRI score of the CSF space were measured. The patients were divided into 2 groups according to the JOA score improvement rate (IR). The relationship between the postoperative MRI score and the JOA score IR was analyzed. RESULTS: The patients in group A experienced better recovery compared with those in group B regarding the JOA, visual analog scale, and neck disability index score at the final follow-up visit. On both axial and sagittal T2-weighed MRI, patients in group A experienced lower improvement of the area of the spinal cord than in group B (P > 0.05). However, the mean improvement in the CSF space in group A was better than that in group B (62.86 ± 30.05 mm2 vs. -6.36 ± 24.58 mm2; P < 0.05), with a greater occupying rate of CSF space in group A at the final visit. A strong correlation was noted between the JOA score IR and postoperative CSF space score (P < 0.01). CONCLUSION: These results suggest that ACAF could provide good decompression of the spinal cord and neurological improvement. Also, recovery of the CSF space correlated closely with the surgical ACAF outcomes for cervical myelopathy due to OPLL.