HDAC1/2-Dependent P0 Expression Maintains Paranodal and Nodal Integrity Independently of Myelin Stability through Interactions with Neurofascins.

The pathogenesis of peripheral neuropathies in adults is linked to maintenance mechanisms that are not well understood. Here, we elucidate a novel critical maintenance mechanism for Schwann cell (SC)-axon interaction. Using mouse genetics, ablation of the transcriptional regulators histone deacetylases 1 and 2 (HDAC1/2) in adult SCs severely affected paranodal and nodal integrity and led to demyelination/remyelination. Expression levels of the HDAC1/2 target gene myelin protein zero (P0) were reduced by half, accompanied by altered localization and stability of neurofascin (NFasc)155, NFasc186, and loss of Caspr and septate-like junctions. We identify P0 as a novel binding partner of NFasc155 and NFasc186, both in vivo and by in vitro adhesion assay. Furthermore, we demonstrate that HDAC1/2-dependent P0 expression is crucial for the maintenance of paranodal/nodal integrity and axonal function through interaction of P0 with neurofascins. In addition, we show that the latter mechanism is impaired by some P0 mutations that lead to late onset Charcot-Marie-Tooth disease.

A simple method of bronchial occlusion with silicone spigots (Endobronchial Watanabe Spigot; EWS®) using a curette.

BACKGROUND: Bronchial occlusion with an Endobronchial Watanabe Spigot (EWS) has been shown to be useful in managing prolonged bronchopleural fistulas and intractable hemoptysis. EWS bronchial occlusion using a curette is less technically demanding. This retrospective study evaluated the clinical utility and simplicity of this method. METHODS: A total of 18 consecutive patients (15 men, 3 women, aged 47-85 years) who underwent bronchial occlusion using an EWS from April 2012 to August 2014 were evaluated. The method involves sticking the tip of a curette into an EWS to the first joint, allowing it to be turned in any direction or at any angle. The time required to occlude the target bronchus was measured on routinely recorded digital videos. Other parameters evaluated included success rates, complications, and clinical outcomes. RESULTS: Of the 18 patients, 11 underwent bronchial occlusion for intractable pneumothorax, 5 for postoperative bronchopleural fistula, two for intractable empyema, and one for hemoptysis. Each patient required 1-7 EWSs (median 4). Target bronchi included the right upper (n = 8), left upper (n = 5), right lower (n = 2), left lower (n = 2), and right middle (n = 1) bronchi. The success rate of EWS insertion into the target bronchus was 100%. Time per EWS occlusion ranged from 65-528 sec (median 158.5 sec). Of the 62 insertions, 36 (58.1%) were completed within 3 min, and 58 (93.5%) within 5 min. Successful outcomes were observed in 15 (83.3%) of the 18 patients. CONCLUSIONS: EWS bronchial occlusion using a curette is a simple method for managing intractable bronchopleural fistulas in daily clinical settings.