TAMI-13. MODULATION OF REDUCTIVE CARBOXYLATION FLUX OF GLUTAMINE IN GLIOBLASTOMA CELLS BY USING OSCILLATING MAGNETIC FIELD

Increased cell proliferation in glioblastoma (GBM) leads to hypoxia in the tumor microenvironment. This is a major concern in GBM patients as it promotes tumor invasion. Glutaminolysis is a hallmark of cancer cells and under hypoxic conditions glutamine metabolism proceeds through reductive carboxylation pathway. Recently, we have shown that oscillating magnetic field (OMF) produces oncolytic effects which can influence cellular metabolism. Here, we have explored the effect of OMF on glutamine metabolism in GBM cells. Patient-derived GBM cells were grown in high glucose (25 mM) DMEM supplemented with 20% fetal bovine serum (FBS), 2.0 mM glutamine and 1.0 mM pyruvate at 37 °C under humidified air and 5% CO2. Cells were divided into 2 groups (Test and Sham; n = 4 each group). When reached confluency (~2.0×106 cells/mL), cells in both groups were treated with 4.0 mM of [U-13C]glutamine in DMEM (supplemented with 20% FBS, and 1.0 mM pyruvate). The “Test” group was subjected to OMF for 3 hours, and the “Sham” group was treated similar to the “Test” group but with non-magnetic rods of the same dimensions as the magnets in the Test group. After 3 h, cells were harvested in 50% methanol analyzed by GC-MS. The 13C-isotopomer analysis showed that glutamine metabolism in GBM cells proceeds through reduction carboxylation, confirmed by the higher levels of M+5 citrate (15.42 ± 1.28 % ) than M+4 citrate (2.05 ± 0.28 %). When GBM cells were treated with OMF, a statistically significant decrease in the citrate M+5 was observed, compared to the “Sham” treated group (15.42 ± 1.28 % vs. 8.89 ± 1.30 %; p = 0.0003). This decrease in M+5 citrate upon OMF treatment clearly indicates that the OMF decreases the reductive carboxylation flux of glutamine in GBM cells which would have therapeutic value in treating GBM patients.

Rhinothermy delivered by nasal high flow therapy in the treatment of the common cold: a randomised controlled trial

BackgroundThe common cold is the most common infectious disease affecting humans and has a substantial economic impact on society. Human rhinoviruses, which cause almost two-thirds of colds, have demonstrated temperature-dependent replication which is optimal between 33°C and 35°C.MethodsThis randomised, single-blind, parallel-group trial completed at a single-centre in New Zealand, recruited 170 participants aged 18–75 years (mean age 27.5 years) who were within 48 hours of common cold symptom onset and had a symptom score (the Modified Jackson Score (MJS)) ≥7 and a negative point-of-care test for influenza. Participants were blinded to the intervention and randomised (1:1) to 5 days of either nasal high flow rhinothermy (rNHF) (100% humidified air delivered at 35 L/min and 41°C for 2 hours daily) (n=85) or ‘sham’ rhinothermy (100% humidified air delivered at 10 L/min and 31°C for 10 min daily) (n=85) and completed daily symptom diaries, which included the MJS, for 14 days, to investigate whether rNHF reduced common cold symptom severity and duration compared with ‘sham’ rhinothermy.ResultsAn intention-to-treat superiority analysis included all randomised participants and showed no difference between treatment groups for the primary outcome, the day 4 MJS analysed by analysis of covariance: mean (SD) 6.33 (3.97) for rNHF vs 5.8 (3.15) for ‘sham’; estimated difference (95% CI) 0.37 (−0.69 to 1.42), p=0.49. There was no difference in time until resolution of symptoms: mean (SD) 5.96 (4.47) days for rNHF vs 6.42 (4.09) days for ‘sham’; estimated difference (95% CI) 1.02 (0.75 to 1.38), p=0.91. There were no serious adverse events related to the study treatments.ConclusionsThis well-powered, single-blind randomised controlled trial does not provide evidence that 5 days of rNHF (100% humidified air heated to 41°C delivered at 35 L/min for 2 hours daily) reduces common cold symptom severity or duration. However, investigation of rNHF in the treatment of influenza is warranted.Trial registration numberACTRN12617001340325.

Effect of Total Pressure and Furnace Tube Material on the Oxidation of T22 in Humidified Air

Oxidation of the Fe-base alloy T22 in humid air at 500 °C was investigated. The samples were exposed for up to 1000 h at 1 bar and 20 bar. The influence of three furnace tube materials, alumina, ET45 and quartz glass, on the oxide scale morphology was investigated. Samples and their cross sections were examined using optical microscopy, scanning electron microscopy, electron probe micro analysis and Raman spectroscopy. Multilayered oxide scales consisting of hematite, magnetite and Fe–Cr spinel were found on all samples. However, the composition and morphology of the oxide scales depend on the furnace tube material and on the system pressure. The system pressure is assumed to change the reaction equilibria and adsorption rates. The tube material changed the initial gas composition by formation of volatile Cr species. This volatilization rate increased at higher system pressures.

Rapid changes in mucociliary transport in the tracheal epithelium caused by unconditioned room air or nebulized hypertonic saline and mannitol are not determined by frequency of beating cilia

Background Inspired air is heated and humidified in the nose before it reaches lower airways. This mechanism is bypassed during tracheostomy, directly exposing the airways to colder and drier air from the environment, known to negatively affect mucociliary transport; however, little is known about how quickly mucociliary transport deteriorates. This study determines the short-term effect of flowing room air and nebulized hypertonic saline and mannitol on mucociliary transport in the trachea. In an ovine perfused in vitro tracheal model (N = 9) the epithelium was exposed to 25 L/min of flow, heated to lamb body temperature (38 °C) and fully saturated with water vapor as the control, followed by either room air (22 °C and 50% relative humidity) or nebulized solutions of NaCl 7% and mannitol 20% up to 1 min for a short duration, until mucociliary transport had visually changed. Mucus transport velocity (MTV) and cilia beat frequency (CBF) were continuously measured with video-microscopy. Results Exposing the tracheal epithelium to air heated to body temperature and fully humidified had stable MTV 9.5 ± 1.1 mm/min and CBF 13.4 ± 0.6 Hz. When exposed to flow of room air, MTV slowed down to 0.1 ± 0.1 mm/min in 2.0 ± 0.4 s followed by a decrease in CBF to 6.7 ± 1.9 Hz, after 2.3 ± 0.8 s. Both MTV and CBF recovered to their initial state when heated and humidified air-flow was re-introduced. Exposing the tracheal epithelium to nebulized hypertonic saline and nebulized mannitol for 1 min increased MTV without a subsequent increase in CBF. Conclusions This study demonstrates mucociliary transport can deteriorate within seconds of exposing the tracheal epithelium to flowing room air and increase rapidly when exposed to nebulized hypertonic solutions. The reduction in MTV precedes slowing of CBF with room air and MTV increases without a subsequent increase in CBF during the nebulization. Their relationship is non-linear and a minimum CBF of approximately 6 Hz is required for MTV > 0, while MTV can reach 10.9 mm/min without CBF increasing. Clinically these findings indicate a potential rapid detrimental effect of breathing with non-humidified air via bypassed upper airways and the short-term effects of nebulized osmotic agents that increase MTV.

Trans-nasal high-flow dehumidified air in acute migraine headaches: A randomized controlled trial

Background Intranasal high flow of dehumidified (dry) air results in evaporative cooling of nasal passages. In this randomized clinical trial, we investigated the effect of dry gas induced nasal cooling on migraine headaches. Methods In this single-blind study, acute migraineurs were randomized to either nasal high-flow dry oxygen, dry air, humidified oxygen or humidified air (control) at 15 L/min for 15 min. All gases were delivered at 37°C. Severity of headache and other migraine associated symptoms (International Classification for Headache Disorders, 3rd edition criteria) were recorded before and after therapy. The primary endpoint was change in pain scores, while changes in nausea, photosensitivity and sound sensitivity scores served as secondary endpoints. A linear regression model was employed to estimate the impact of individual treatment components and their individual interactions. Results Fifty-one patients (48 ± 15 years of age, 82% women) were enrolled. When compared to the control arm (humidified air), all therapeutic arms showed a significantly greater reduction in pain scores (primary endpoint) at 2 h of therapy with dry oxygen (−1.6 [95% CI −2.3, −0.9]), dry air (−1.7 [95% CI −2.6, −0.7)]), and humidified oxygen (−2.3 [95% CI −3.5, −1.1]). A significantly greater reduction in 2-h photosensitivity scores was also noted in all therapeutic arms (−1.8 [95% CI −3.2, −0.4], dry oxygen; −1.7 [95% CI −2.9, −0.4], dry air; (−2.1 [95% CI −3.6, −0.6], humidified oxygen) as compared to controls. The presence of oxygen and dryness were independently associated with significant reductions in pain and photosensitivity scores. No adverse events were reported. Conclusion Trans-nasal high-flow dry gas therapy may have a role in reducing migraine associated pain. Clinical Trial registration: NCT04129567

Rapid changes in mucociliary transport in the tracheal epithelium caused by unconditioned room air or nebulized hypertonic saline and mannitol are not determined by frequency of beating cilia

BACKGROUND: Inspired air is heated and humidified in the nose before it reaches lower airways. This mechanism is bypassed during tracheostomy, directly exposing the airways to colder and drier air from the environment, known to negatively affect mucociliary transport; however, little is known about how quickly mucociliary transport deteriorates. This study determines the short-term effect of flowing room air and nebulized hypertonic saline and mannitol on mucociliary transport in the trachea. In an ovine perfused in vitro tracheal model (N=9) the epithelium was exposed to 25 L/min of flow, heated to lamb body temperature (38°C) and fully saturated with water vapor as the control, followed by either room air (22°C and 50% relative humidity) or nebulized solutions of NaCl 7% and mannitol 20% up to 1 min for a short duration, until mucociliary transport had visually changed. Mucus transport velocity (MTV) and cilia beat frequency (CBF) were continuously measured with video-microscopy. RESULTS: Exposing the tracheal epithelium to air heated to body temperature and fully humidified had stable MTV 9.5±1.1mm/min and CBF 13.4±0.6Hz. When exposed to flow of room air, MTV slowed down to 0.1±0.1mm/min in 2.0±0.4seconds followed by a decrease in CBF to 6.7±1.9Hz, after 2.3±0.8 second. Both MTV and CBF recovered to their initial state when heated and humidified air- flow was re-introduced. Exposing the tracheal epithelium to nebulized hypertonic saline and nebulized mannitol for 1 min increased MTV without a subsequent increase in CBF.CONCLUSIONS: This study demonstrates mucociliary transport can deteriorate within seconds of exposing the tracheal epithelium to flowing room air and increase rapidly when exposed to nebulized hypertonic solutions. The reduction in MTV precedes slowing of CBF with room air and MTV increases without a subsequent increase in CBF during the nebulization. Their relationship is non-linear and a minimum CBF of approximately 6Hz is required for MTV>0, while MTV can reach 10.9mm/min without CBF increasing. Clinically these findings indicate a potential rapid detrimental effect of breathing with non-humidified air via bypassed upper airways and the short-term effects of nebulized osmotic agents that increase MTV.

Variability in tracheal mucociliary transport is not controlled by beating cilia in lambs in vivo during ventilation with humidified and non-humidified air

Mucociliary transport in the respiratory epithelium depends on beating of cilia to move a mucus layer containing trapped inhaled particles towards the mouth. Little is known about the relationship between cilia beat frequency (CBF) and mucus transport velocity (MTV) in vivo under normal physiological conditions and when inspired air is dry or not fully humidified. This study was designed to use video-microscopy to simultaneously measure CBF and MTV in the tracheal epithelium through an implanted optical window in mechanically ventilated lambs. The inspired air in 6 animals was heated to body temperature and fully saturated with water for 4 hours as a baseline. In another series of experiments, 5 lambs were ventilated with air at different temperatures and humidities while the mucosal surface temperature was also monitored with infrared macro-imaging. In the baseline experiments during ventilation with fully humidified air at body temperature CBF remained fairly constant, mean 13.9±1.6Hz but MTV varied considerably between 0.1 and 26.1mm/min with mean 11.0±3.9mm/min, resulting in a maximum mucus displacement of 34.2µm/cilia beat. Fully humidified air at body temperature prevented fluctuations in the surface temperature during breathing indicating a thermodynamic balance in the airways. When lambs were ventilated with dryer air, the mucosal surface temperature and MTV dropped without a significant change in CBF. When inspired air was dry, mainly latent heat (92%) was transferred to air in the trachea, reducing the surface temperature by 5°C. Reduced humidity of the inspired air lowered the surface temperature and reduced MTV in the epithelium during ventilation.