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Summary Background Dermal papilla cells (DPCs) play a key role in hair regeneration and morphogenesis. Therefore, tremendous efforts have been made to promote DPC hair inductivity. Objectives The aim of this study was to investigate the mitogenic and hair inductive effects of hypoxia on DPCs and examine the underlying mechanism of hypoxia‐induced stimulation of DPCs. Methods DPCs' hair inductivity was examined under normoxia (20% O2) and hypoxia (2% O2). Results Hypoxia significantly increased the proliferation and delayed senescence of DPCs via Akt phosphorylation and downstream pathways. Hypoxia upregulated growth factor secretion of DPCs through the mitogen‐activated protein kinase pathway. Hypoxia‐preconditioned DPCs induced the telogen‐to‐anagen transition in C3H mice, and also enhanced hair neogenesis in a hair reconstitution assay. Injected green fluorescent protein‐labelled DPCs migrated to the outer root sheath of the hair follicle, and hypoxia‐preconditioning increased survival and migration of DPCs in vivo. Conditioned medium obtained from hypoxia increased the hair length of mouse vibrissa follicles via upregulation of alkaline phosphatase, vascular endothelial growth factor, and glial cell line‐derived neurotrophic factor. We examined the mechanism of this hypoxia‐induced stimulation, and found that reactive oxygen species (ROS) play a key role. For example, inhibition of ROS generation by N‐acetylcysteine or diphenyleneiodonium treatment attenuated DPCs' hypoxia‐induced stimulation, but treatment with ROS donors induced mitogenic effects and anagen transition. NADPH oxidase 4 is highly expressed in the DPC nuclear region, and NOX4 knockout by CRISPR‐Cas9 attenuated the hypoxia‐induced stimulation of DPCs. Conclusions Our results suggest that DPC culture under hypoxia has great advantages over normoxia, and is a novel solution for producing DPCs for cell therapy. Whatʼs already known about this topic? Dermal papilla cells (DPCs) play a key role in hair regeneration and morphogenesis, but they are difficult to isolate and expand for use in cell therapy. Tremendous efforts have been made to increase proliferation of DPCs and promote their hair formation ability. What does this study add? Hypoxia (2% O2) culture of DPCs increases proliferation, delays senescence and enhances hair inductivity of DPCs. Reactive oxygen species play a key role in hypoxia‐induced stimulation of DPC. What is the translational message? Preconditioning DPCs under hypoxia improves their hair regenerative potential, and is a novel solution for producing DPCs for cell therapy to treat hair loss.

Frequent arousals during sleep degrade the quality of sleep and result in sleep fragmentation. Visual inspection of physiological signals to detect the arousal events is inconvenient and time-consuming work. The purpose of this study was to develop an automatic algorithm to detect the arousal events. We proposed the automatic method to detect arousals based on time-frequency analysis and the support vector machine (SVM) classifier using a single channel sleep electroencephalogram (EEG). The performance of our method has been assessed using polysomnographic (PSG) recordings of nine patients with sleep apnea, snoring and excessive daytime sleepiness (EDS). By the proposed method, we could obtain sensitivity of 87.92% and specificity of 95.56% for the training sets, and sensitivity of 75.26% and specificity of 93.08% for the testing sets, respectively. We have shown that proposed method was effective for detecting the arousal events.

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ORR in T790M+ patients Dose QD 20 mg 40 mg 80 mg 120 mg 160 mg 240 mg Evaluable patients*, n 2 25 18 22 18 8 ORR, n (%)