Central sleep apnea treated by a constant low-dose CO2 supplied by a novel device.

CO2 inhalation has been previously reported as a treatment for central sleep apnea both when associated with heart failure or where the cause is unknown. Here, we evaluated a novel CO2 supply system using a novel open mask capable of comfortably delivering a constantly inspired fraction of CO2 ([Formula: see text]) during sleep. We recruited 18 patients with central sleep apnea (13 patients with cardiac disease, and 5 patients idiopathic) diagnosed by diaphragm electromyogram (EMG) recordings made during overnight full polysomnography (PSG) (night 1). In each case, the optimal [Formula: see text] was determined by an overnight manual titration with PSG (night 2). Titration commenced at 1% CO2 and increased by 0.2% increments until central sleep apnea (CSA) disappeared. Patients were then treated on the third night (night 3) with the lowest therapeutically effective concentration of CO2 derived from night 2. Comparing night 1 and night 3, both apnea-hypopnea index (AHI; 31 ± 14 vs. 6 ± 3 events/h, P < 0.01) and arousal index (22 ± 8 vs. 15 ± 8 events/h, P < 0.01) were significantly improved during CO2 treatment. Sleep efficiency improved from 71 ± 18 to 80 ± 11%, P < 0.05, and sleep latency was shorter (23 ± 18 vs. 10 ± 10 min, P < 0.01). Heart rate was not different between night 1 and night 3. Our data confirm the feasibility of our CO2 delivery system and indicate that individually titrated CO2 supplementation with a novel device including a special open mask can reduce sleep disordered breathing severity and improve sleep quality. Randomized controlled studies should now be undertaken to assess therapeutic benefit for patients with CSA.NEW & NOTEWORTHY A novel device using a special mask was developed and proved that CO2 therapy using the device could eliminate central sleep apnea (CSA) events and improve sleep quality including reducing arousal index in patients with heart failure. The device would become a useful clinical treatment for heart failure patients with CSA.

Molecular cloning and characterization of two pathogenesis-related ß-1,3-glucanase genes ScGluA1 and ScGluD1 from sugarcane infected by Sporisorium scitamineum.

KEY MESSAGE: Two ß-1,3-glucanase genes from sugarcane were cloned and characterized. They were all located in apoplast and involves in different expression patterns in biotic and abiotic stress. Smut caused by Sporisorium scitamineum is a serious disease in the sugarcane industry. ß-1,3-Glucanase, a typical pathogenesis-related protein, has been shown to express during plant-pathogen interaction and involves in sugarcane defense response. In this study, ß-1,3-glucanase enzyme activity in the resistant variety increased faster and lasted longer than that of the susceptible one when inoculated with S. scitamineum, along with a positive correlation between the activity of the ß-1,3-glucanase and smut resistance. Furthermore, two ß-1,3-glucanase genes from S. scitamineum infected sugarcane, ScGluA1 (GenBank Accession No. KC848050) and ScGluD1 (GenBank Accession No. KC848051) were cloned and characterized. Phylogenetic analysis suggested that ScGluA1 and ScGluD1 clustered within subfamily A and subfamily D, respectively. Subcellular localization analysis demonstrated that both gene products were targeted to apoplast. Escherichia coli Rosetta (DE3) cells expressing ScGluA1 and ScGluD1 showed varying degrees of tolerance to NaCl, CdCl2, PEG, CuCl2 and ZnSO4. Q-PCR analysis showed up-regulation of ScGluA1 and slight down-regulation of ScGluD1 in response to S. scitamineum infection. It suggested that ScGluA1 may be involved in the defense reaction of the sugarcane to the smut, while it is likely that ScGluD1 was inhibited. The gene expression patterns of ScGluA1 and ScGluD1, in response to abiotic stresses, were similar to sugarcane response against smut infection. Together, ß-1,3-glucanase may function in sugarcane defense mechanism for S. scitamineum. The positive responses of ScGluA1 and the negative responses of ScGluD1 to biotic and abiotic stresses indicate they play different roles in interaction between sugarcane and biotic or abiotic stresses.