Photocatalytic reduction of carbon dioxide by BiTeX (X = Cl, Br, I) under visible-light irradiation.

In this study, a series of BiTeX (X = Cl, Br, I) photocatalysts were successfully synthesized via a simple hydrothermal method. The synthesis process involved dissolving BiX3 and Te powder in toluene to identify the most efficient material for photocatalytic activity. The main objective of this approach is to facilitate the conversion of carbon dioxide into sustainable solar fuels, such as alcohols and hydrocarbons, offering an appealing solution to address environmental concerns and energy crises. The BiTeX photocatalysts demonstrated significant proficiency in converting CO2 into CH4, particularly BiTeCl exhibited a notable photocatalytic conversion rate of up to 0.51 µmolg-1h-1. The optimized BiTeX photocatalysts displayed a gradual and selective transition from CO2 to CH4, ultimately producing valuable hydrocarbons (C2+). Furthermore, owing to their ability to reduce CO2, these photocatalysts show promise as materials for mitigating environmental pollution.

Photoreduction of carbon dioxide and photodegradation of organic pollutants using alkali cobalt oxides MCoO2 (M = Li or Na) as catalysts.

The recycling of lithium batteries should be prioritized, and the use of discarded alkali metal battery electrode materials as photocatalysts merits research attention. This study synthesized alkali metal cobalt oxide (MCoO2, M = Li or Na) as a photocatalyst for the photoreduction of CO2 and degradation of toxic organic substances. The optimized NaCoO2 and LiCoO2 photocatalysts increased the photocatalytic CO2-CH4 conversion rate to 21.0 and 13.4 µmol g-1 h-1 under ultraviolet light irradiation and to 16.2 and 5.3 µmol g-1 h-1 under visible light irradiation, which is 17 times higher than that achieved by TiO2 P25. The rate constants of the optimized reactions of crystal violet (CV) with LiCoO2 and NaCoO2 were 2.29 × 10-2 and 4.35 × 10-2 h-1, respectively. The quenching effect of the scavengers and electron paramagnetic resonance in CV degradation indicated that active O2•-, 1O2, and h+ play the main role, whereas •OH plays a minor role for LiCoO2. The hyperfine splitting of the DMPO-•OH and DMPO-•CH3 adducts was aN = 1.508 mT, aHß = 1.478 mT and aN = 1.558 mT, aHß = 2.267 mT, respectively, whereas the hyperfine splitting of DMPO+• was aN = 1.475 mT. The quenching effect also indicated that active O2•- and h+ play the main role and that •OH and 1O2 play a minor role for NaCoO2. The hyperfine splitting of the DMPO-•OH and DMPO+• adducts was aN = 1.517 mT, aHß = 1.489 mT and aN = 1.496 mT, respectively. Discarded alkali metal battery electrode materials can be reused as photocatalysts to address environmental pollution.

Controlled hydrothermal synthesis of BiOxCly/BiOmBrn/g-C3N4 composites exhibiting visible-light photocatalytic activity.

The first systematic synthesis of bismuth oxychloride/bismuth oxybromide/graphitic carbon nitride (BiOxCly/BiOmBrn/g-C3N4) nano-composites used a controlled hydrothermal method. The structure, morphology and characteristic of BiOxCly/BiOmBrn/g-C3N4 photocatalyst were measured by XRD, UV-vis-DRS, FT-IR, FE-TEM, FE-SEM-EDS, PL, BET, HR-XPS and EPR. Under visible light irradiation, the photodegradation activity was evaluated for the decolorization of crystal violet (CV) and 2-hydroxybenzoic acid (2-HBA) in aqueous solution. The catalytic performance showed that, when using sample BB2C1-4-250-30 wt% g-C3N4 composite as a photocatalyst, the best reaction-rate-constant (k) was 0.071 h-1. It was 1.5 times higher than the k value of BB2C1-4-250 as a photocatalyst. From the scavenging effect of various scavengers, the results of EPR showed that reactive OH was the main scavenger, while O2-, h+ and 1O2 were the second scavenger in CV degradation. In this study, a possible photodegradation mechanism was proposed and discussed. In this work, our method of BiOxCly/BiOmBrn/g-C3N4 preparation could be used for future mass production and the BiOxCly/BiOmBrn/g-C3N4 composite materials could be applied to the environmental pollution control in future.

[Hypobaric hypoxia increases the expression of death receptor 5 and inhibits that of FLICE-like inhibitory protein in the rat testis].

OBJECTIVE: To evaluate the effects of hypobaric hypoxia on the expressions of death receptor 5 (DR5) and cellular FLICE-like inhibitory protein (c-FLIP) and the distribution of c-FLIP in the rat testis. METHODS: Forty adult male SD rats were randomly divided into four groups of equal number: normoxia control, 3 d hypoxia, 15 d hypoxia and 30 d hypoxia. The control rats were raised at 300 m above the sea level, while the latter three groups of rats in a hypobaric chamber at a simulated altitude of 4000 m for 5, 15 and 30 days, respectively. Then the expressions of DR5 and c-FLIP were detected by immunoblotting and the distribution of c-FLIP in the testis observed by immunofluorescence. RESULTS: The expressions of DR5 were 2.04 +/- 0.11, 1.97 +/- 0.12 and 2.34 +/- 0.11 in the 3 d, 15 d and 30 d hypoxia groups, respectively, significantly higher than 1.78 +/- 0.09 in the normoxia group (P < 0.05). The expressions of c-FLIP were 0.87 +/- 0.03 and 0.74 +/- 0.07 in the 15 d and 30 d hypoxia groups, respectively, significantly lower than 1.03 +/- 0.02 in the normoxia group (P < 0.05). CONCLUSION: Simulated hypobaric hypoxia at 4000 m above the sea level increased the expression of DR5 and inhibited that of c-FLIP in the rat testis.

Fabrication and characterization of ZnGa1.01Te2.13/g-C3N4 heterojunction with enhanced photocatalytic activity.

The extensive consumption of fossil fuels increases CO2 concentration in the atmosphere, resulting in serious global warming problems. Meanwhile, the problem of water contamination by organic substances is another significant global challenge. We have successfully synthesized ZnGa1.01Te2.13/g-C3N4 (ZGT/GCN) composites for the first time as effective photocatalysts for both pollutant degradation and CO2 reduction. ZGT/GCN composites were synthesized by a simple hydrothermal method. The prepared photocatalysts were characterized by XRD, SEM, TEM-EDS, DRS, BET, PL, and XPS. The ZGT/GCN heterojunction exhibited considerably enhanced photocatalytic activity in the degradation of crystal violet (CV) as well as in the photoreduction of CO2 when compared to pure ZGT and GCN semiconductors. The optimal rate constant for CV degradation was obtained with the ZGT-80%GCN composite (0.0442 h-1), which is higher than the constants obtained with individual ZGT and GCN by 7.75 and 1.63 times, respectively. Moreover, the CO2 reduction yields into CH4 by ZGT-80%GCN was 1.013 µmol/g in 72 h, which is 1.21 and 1.08 times larger than the yields obtained with ZGT and GCN. Scavenger and ESR tests were used to propose the photocatalytic mechanism of the ZGT/GCN composite as well as the active species in the CV degradation.

Visible-light-driven photocatalysis of carbon dioxide and organic pollutants by MFeO2 (M = Li, Na, or K).

In recent years, lithium-containing ceramic materials have attracted considerable research attention as high-temperature adsorbents of carbon dioxide. The recycling of electrode materials from spent lithium-ion batteries for use as photocatalysts in recovering CO2 and degrading organic pollutants is worthy of exploration. Solid, magnetic ferrite-containing photocatalysts are easily separated from reaction solutions by using magnetic devices. Solid catalysts (e.g., LiFeO2, LiFe5O8, NaFeO2, and K2Fe2O4) were prepared through the calcination of Fe2O3 and M2CO3. CO2 was photoreduced and crystal violet (CV) and 2-hydroxybenzoic acid (2-HBA) were photodegraded under visible light irradiation. The optimized K2Fe2O4 photocatalyst increased the rate of photocatalytic conversion from CO2 to methane at 20.9 µmol g-1 h-1. The catalytic efficiency indicated that the optimized reaction rate constants of CV with LiFeO2, NaFeO2, and K2Fe2O4 were 2.98 × 10-1, 5.32 × 10-1, and 4.36 × 10-1 h-1, respectively. The quenching effect achieved through the use of various scavengers and the electron paramagnetic resonance in CV degradation revealed the substantial contribution of the reactive superoxide anion radical O2- and the minor roles of h+ and the OH radical. Its usefulness in the synthesis of solid-base catalyst MFeO2 is promising for environmental control and relevant applications, particularly in solar energy manufacturing.

Author Correction: Neuroprotectants attenuate hypobaric hypoxia-induced brain injuries in cynomolgus monkeys.

Following the publication of our paper (Zhang et al., 2020), it has come to our attention that we erroneously listed two funding sources unrelated to this study in the "ACKNOWLEDGEMENTS" section. Hereby, we wish to update the "ACKNOWLEDGEMENTS" section as a correction.

Hypoxic training increases metabolic enzyme activity and composition of alpha-myosin heavy chain isoform in rat ventricular myocardium.

Cardiac muscle adaptation is essential for maintaining physical capacity after ascending to high altitude. This study examines the effects of high altitude training on myocardial metabolic enzyme activity and composition of alpha-myosin heavy chain (MHC). Rats were randomly divided into normobaric sedentary (NS) and training (NT) groups, and hypobaric sedentary (HS) and training (HT) groups. HS and HT rats were exposed to hypobaric hypoxia (simulated 4,000-5,000 m) for 5 weeks (24 h/day), and HT rats simultaneously received swim training. Hypoxia exposure for 5 weeks led to a decrease in succinate dehydrogenase (SDH) and citrate synthase (CS) activities in the left ventricle (LV), and a decrease in CS, hexokinase (HK) and total lactate dehydrogenase (LDH) activities in the right ventricle (RV) (p < 0.05, HS vs. NS). Furthermore, 1 h/day swim training during hypoxia exposure enhanced the CS activity in LV and the SDH and CS activities in RV (p < 0.05, HT vs. HS). The percentages of alpha-MHC in both ventricles in HT were higher than those in HS (p < 0.05). We conclude that exercise training at high altitude is beneficial for cardiac muscle adaptation to hypoxia by increasing activities of enzymes and percentage of alpha-MHC. This may contribute to improved cardiac function and work capacity at high altitude.

Lead bismuth oxybromide/graphene oxide: Synthesis, characterization, and photocatalytic activity for removal of carbon dioxide, crystal violet dye, and 2-hydroxybenzoic acid.

A novel lead bismuth oxybromide/graphene oxide (PbBiO2Br/GO) composite photocatalyst were prepared using a controlled and nontemplate hydrothermal technique with PbBiO2Br and GO as the starting material. The heterojunction photocatalysts were characterized through XRD, FE-SEM-EDS, HR-TEM, XPS, DR-UV-vis, BET, PL, EPR, and UPS. Under the optimal synthesis conditions, the photocatalytic activity of PbBiO2Br/GO composites was much higher than that of PbBiO2Br. Under 25 °C, 1 atm, and 432-nm visible light irradiation at, the optimized PbBiO2Br/GO increased the rate (at 1.913 µmol g-1 h-1) of photocatalytic conversion from carbon dioxide (CO2) to methane (CH4). This conversion rate was higher than that of the original PbBiO2Br material (0.957 µmol g-1 h-1). Therefore, PbBiO2Br/GO is superior for CH4 production and has great potential as CO2 photoreduction catalysts. In addition, such catalytic performance (when using 0.05 wt%-GO/PbBiO2Br composite as a photocatalyst) indicates that the optimal reaction rate constants of crystal violet (CV) and 2-hydroxybenzoic acid (2-HBA) are 0.1278 and 0.0093 h-1, respectively, which are 1.82 and 1.24 times the reaction rate constant of PbBiO2Br as a photocatalyst, respectively. Our findings are useful for PbBiO2Br/GO synthesis and in its future environmental applications, particularly in solar fuel manufacture.

Neuroprotectants attenuate hypobaric hypoxia-induced brain injuries in cynomolgus monkeys.

Hypobaric hypoxia (HH) exposure can cause serious brain injury as well as life-threatening cerebral edema in severe cases. Previous studies on the mechanisms of HH-induced brain injury have been conducted primarily using non-primate animal models that are genetically distant to humans, thus hindering the development of disease treatment. Here, we report that cynomolgus monkeys ( Macacafascicularis) exposed to acute HH developed human-like HH syndrome involving severe brain injury and abnormal behavior. Transcriptome profiling of white blood cells and brain tissue from monkeys exposed to increasing altitude revealed the central role of the HIF-1 and other novel signaling pathways, such as the vitamin D receptor (VDR) signaling pathway, in co-regulating HH-induced inflammation processes. We also observed profound transcriptomic alterations in brains after exposure to acute HH, including the activation of angiogenesis and impairment of aerobic respiration and protein folding processes, which likely underlie the pathological effects of HH-induced brain injury. Administration of progesterone (PROG) and steroid neuroprotectant 5α-androst-3ß,5,6ß-triol (TRIOL) significantly attenuated brain injuries and rescued the transcriptomic changes induced by acute HH. Functional investigation of the affected genes suggested that these two neuroprotectants protect the brain by targeting different pathways, with PROG enhancing erythropoiesis and TRIOL suppressing glutamate-induced excitotoxicity. Thus, this study advances our understanding of the pathology induced by acute HH and provides potential compounds for the development of neuroprotectant drugs for therapeutic treatment.

[Effects of liquids with different osmotic pressure and different oxygen concentration on resuscitation of hemorrhagic shock at high altitude in rat].

OBJECTIVE: To compare the effects of liquids with different osmotic pressure and different oxygen concentration on resuscitation of hemorrhagic shock at high altitude. METHODS: Hemorrhagic shock model of Sprague-Dawley (SD) rats was reproduced by Weigger method at the altitude of 3,658 meters. After 1 hour blood loss, the rats were treated either with normal saline, 75 g/L hypertonic saline solution, 60 g/L dextran 40 solution, solution of 75 g/L hypertonic saline solution with 60 g/L dextran 40, or hypertonic sodium chloride hydroxyethyl starch 40 solution, and all the above solutions were oxygenated with oxygen by high pressure. All the solutions were infused via external jugular vein (4 ml/kg) to resuscitate the rats, and the effects of different solutions on blood pressure (BP), blood gas, intraventricular pressure, water contents of lung or brain, survival time and survival rates were observed. RESULTS: The BP, mean arterial pressure (MAP), partial pressure of oxygen in artery (PaO2), left ventricular systolic pressures (LVSP), maximum upstroke velocity (+dp/dt max) and maximum descending velocity (-dp/dt max) of intraventricular pressure, survival time and survival rate were increased (P<0.05 or P<0.01), but the survival time of the rats in groups treated with hypertonic solutions or hypertonic colloid solutions was obviously prolonged. In particular, survival time and survival rate of the rats in the groups treated with hypertonic colloid solutions were raised more significantly than those of other groups. Besides, the results showed that BP rose steadily in all the groups, PaO2 and LVSP of these groups significantly increased, but partial pressure of carbon dioxide in artery (PaCO2) showed no significant change. Infusion of 4 ml/kg of liquids did not increase water contents of lung or brain. Hyperoxic solutions had no effect on the right ventricular pressure, but the oxygenated liquids could lower the right ventricular pressure at the beginning of resuscitation, suggesting that oxygen transfer through the vein could lower the pulmonary artery pressure and improve the right ventricle function. CONCLUSION: Liquids with different osmotic pressure and at different oxygen concentration showed therapeutical effect on hemorrhagic shock at high altitude in rat, with hypertonic colloid solution being the best among the liquids under examination.

Bismuth oxyfluoride/bismuth oxyiodide nanocomposites enhance visible-light-driven photocatalytic activity.

This is the first paper to report a series of bismuth oxyfluoride/bismuth oxyiodide (BiOpFq/BiOxIy) nanocomposites with different F/I molar ratios, pH values, and reaction temperatures that were synthesized through a template-free and controlled hydrothermal method. These nanocomposites were characterized through scanning electron microscope energy dispersive microscopy (SEM-EDS), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier-transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), and diffuse reflectance spectroscopy (DRS). Under visible-light irradiation, the BiOpFq/BiOxIy composites exhibited excellent photocatalytic activities in the degradation of crystal violet (CV) and 2-hydroxybenzoic acid (HBA). The order of rate constants was BiOF/BiOI > BiOI ≫ BiOF. The photocatalytic activity of BiOF/BiOI composites reached a maximum rate constant of 0.2305 h-1, 1.2 times higher than that of BiOI and 100 times higher than that of BiOF. Thus, the derived BiOF/BiOI is crucial for photocatalytic activity enhancement. After the removal of CV in the third cycle, no apparent deficits in photocatalytic activity were observed, and the observed deficit was 8.2% during the fifth run. Overall, the catalytic activity and stability observed for the proposed composites were determined to be adequate under visible-light irradiation. For various scavengers, the noted quenching effects demonstrated that reactive O2- has a notable role in the degradation of the applied CV.

[The clinical significance of leucocytosis and increase in interleukin content in acute mountain sickness complicated with multiple organ dysfunction syndrome].

OBJECTIVE: To study the role of white blood cell (WBC) and interleukins (ILs) in acute mountain sickness (AMS) complicated with multiple organ dysfunction syndrome (MODS). METHODS: Three thousand one hundred and eighty-four patients suffering from severe AMC in the past 50 years were surveyed with questionnaire. Correlation analysis was done to explore the relationship between differential count of WBC and elevation of ILs contents and MODS. RESULTS: There was no difference in differential count of WBC between essential high altitude pulmonary edema (HAPE) and secondary HAPE. No difference was also found between simple HAPE and high altitude cerebral edema (HACE). However, obvious difference in WBC was found between HACE accompanied by HAPE and simple HAPE or simple HACE in the differential counts of WBC, counts of WBC and neutrophil were significantly elevated, while lymphocyte was significantly declined (all P < 0.05). The count of WBC in people suffering from AMS accompanied by MODS was higher than patients only suffering from AMS, lymphocyte was significantly decreased, the difference was obviously (both P < 0.01). The content of tumor necrosis factor-alpha (TNF-alpha), IL-1, IL-2, IL-6 and IL-8 of severe AMS patients were obviously higher than that of normal people, therefore the content of IL-4 in severe AMS patients was obviously lower than that normal people the difference were obvious (all P < 0.01). CONCLUSION: People suffering from AMS also exist systemic inflammatory response syndrome (SIRS). SIRS play an important part in MODS which is a major cause of AMS, and it's a critical factor of high altitude MODS.

[Analysis of 3,184 cases with acute mountain sickness complicated by multiple organ dysfunction syndrome].

OBJECTIVE: To investigate and analyze the probability of acute mountain sickness (AMS) [including high-altitude cerebral edema (HACE) and high-altitude pulmonary edema (HAPE)] complicated by multiple organ dysfunction syndrome (MODS) and its pathogenetic mechanisms. METHODS: Questionnaire survey was made to retrospectively study the hospitalization cases in the past 50 years, and the incidence of high-altitude MODS (H-MODS) were statistically analyzed to determine the main causes and pathogenic mechanism of MODS. RESULTS: Among 3 184 cases with severe AMS, 83 cases conformed to the diagnostic criteria of diagnosis of H-MODS, and the incidence was 2.6%. The pathogenesis of acute H-MODS might be related to the activation of inflammation pathways, activation of blood clotting pathways and the damage to gastrointestinal mucosa barrier. Therefore, improving the diagnosis and the treatment effects of H-MODS is an important measure to increase cure rate of AMS and to decrease its death rate. CONCLUSION: AMS complicated by multiple organ damage (MOD) is the main factor that influences the therapeutic efficacy. Prompt effective remedy on the spot is a significant measure to reduce incidence of MOD.

[Nitrogen Removal Effect and Conversion Characteristics of Nitrous Oxide in Single-stage and Multi-stage A/O Processes].

The single-stage A/O and multi-stage A/O processes were simulated by sequencing batch reactors (SBRs) with alternate stirring and aeration. The removal efficiency of nitrogen and the release mechanism of N2O were studied under the identical conditions of influent quality, hydraulic retention time (HRT), sludge retention time(SRT), temperature and anoxic/oxic (A/O) retention time ratio. Experimental results showed that COD or ammonia-nitrogen removal had no significant difference between the single-stage and the multi-stage A/O processes for the influent quality equivalent to municipal wastewater. However, TN removal efficiency of the former was better than the later with 72.1% and 52.2%, respectively. In the conversion of total nitrogen, during the typical cycle in the single-stage A/O and multi-stage A/O processes, the yields of N2O were 16.95 mg and 3.95 mg, respectively. The conversion rate, which is the ratio of N2O yield and TN removal, was respectively 11.47% and 4.11%. N2O production and emission occurred mainly in aerobic (nitrification) phase while there was little N2O emission in anoxic (denitrification) phase. Although the dominant species of AOB was both Nitrosomonas in the single-stage A/O and the multi-stage A/O processes under the same operating conditions, it was more conducive to the growth of nitrifying bacteria (AOB, NOB) in the single-stage A/O process with the greater abundance of Nitrosomonas. Meanwhile, the type and abundance of NOB in the single-stage A/O process were significantly more than in the multi-stage A/O process too. Therefore, it is more competitive to deal with the high-strengthening ammonia-nitrogen wastewater in the single-stage A/O process. In the actual operation of wastewater treatment, using appropriate partitions of A/O or oxygen-supplying modes can not only result in better nitrogen removal but also decrease the secondary pollution caused by N2O to the atmosphere.

Intermittent Oxygen Inhalation with Proper Frequency Improves Overall Health Conditions and Alleviates Symptoms in a Population at High Risk of Chronic Mountain Sickness with Severe Symptoms.

BACKGROUND: Oxygen inhalation therapy is essential for the treatment of patients with chronic mountain sickness (CMS), but the efficacy of oxygen inhalation for populations at high risk of CMS remains unknown. This research investigated whether oxygen inhalation therapy benefits populations at high risk of CMS. METHODS: A total of 296 local residents living at an altitude of 3658 m were included; of which these were 25 diagnosed cases of CMS, 8 cases dropped out of the study, and 263 cases were included in the analysis. The subjects were divided into high-risk (180 ≤ hemoglobin (Hb) <210 g/L, n = 161) and low-risk (Hb <180 g/L, n = 102) groups, and the cases in each group were divided into severe symptom (CMS score ≥6) and mild symptom (CMS score 0-5) subgroups. Severe symptomatic population of either high- or low-risk CMS was randomly assigned to no oxygen intake group (A group) or oxygen intake 7 times/week group (D group); mild symptomatic population of either high- or low-risk CMS was randomly assigned to no oxygen intake group (A group), oxygen intake 2 times/week group (B group), and 4 times/week group (C group). The courses for oxygen intake were all 30 days. The CMS symptoms, sleep quality, physiological biomarkers, biochemical markers, etc., were recorded on the day before oxygen intake, on the 15th and 30th days of oxygen intake, and on the 15th day after terminating oxygen intake therapy. RESULTS: A total of 263 residents were finally included in the analysis. Among these high-altitude residents, CMS symptom scores decreased for oxygen inhalation methods B, C, and D at 15 and 30 days after oxygen intake and 15 days after termination, including dyspnea, palpitation, and headache index, compared to those before oxygen intake (B group: Z = 5.604, 5.092, 5.741; C group: Z = 4.155, 4.068, 4.809; D group: Z = 6.021, 6.196, 5.331, at the 3 time points respectively; all P < 0.05/3 vs. before intake). However, dyspnea/palpitation (A group: Z = 5.003, 5.428, 5.493, both P < 0.05/3 vs. before intake) and headache (A group: Z = 4.263, 3.890, 4.040, both P < 0.05/3 vs. before intake) index decreased significantly also for oxygen inhalation method A at all the 3 time points. Cyanosis index decreased significantly 30 days after oxygen intake only in the group of participants administered the D method (Z = 2.701, P = 0.007). Tinnitus index decreased significantly in group A and D at 15 days (A group: Z = 3.377, P = 0.001, D group: Z = 3.150, P = 0.002), 30 days after oxygen intake (A group: Z = 2.836, P = 0.005, D group: Z = 5.963, P < 0.0001) and 15 days after termination (A group: Z = 2.734, P = 0.006, D group: Z = 4.049, P = 0.0001), and decreased significantly in the group B and C at 15 days after termination (B group: Z = 2.611, P = 0.009; C group: Z = 3.302, P = 0.001). In the population at high risk of CMS with severe symptoms, oxygen intake 7 times/week significantly improved total symptom scores of severe symptoms at 15 days (4 [2, 5] vs. 5.5 [4, 7], Z = 2.890, P = 0.005) and 30 days (3 [1, 5] vs. 5.5 [2, 7], Z = 3.270, P = 0.001) after oxygen intake compared to no oxygen intake. In the population at high risk of CMS with mild symptoms, compared to no oxygen intake, oxygen intake 2 or 4 times/week did not improve the total symptom scores at 15 days (2 [1, 3], 3 [1, 4] vs. 3 [1.5, 5]; χ2 = 2.490, P = 0.288), and at 30 days (2 [0, 4], 2 [1, 4.5] vs. 3 [2, 5]; χ2 = 3.730, P = 0.155) after oxygen intake. In the population at low risk of CMS, oxygen intake did not significantly change the white cell count and red cell count compared to no oxygen intake, neither in the severe symptomatic population nor in the mild symptomatic population. CONCLUSIONS: Intermittent oxygen inhalation with proper frequency might alleviate symptoms in residents at high altitude by improving their overall health conditions. Administration of oxygen inhalation therapy 2-4 times/week might not benefit populations at high risk of CMS with mild CMS symptoms while administration of therapy 7 times/week might benefit those with severe symptoms. Oxygen inhalation therapy is not recommended for low-risk CMS populations.

Metabolite Modulation in Human Plasma in the Early Phase of Acclimatization to Hypobaric Hypoxia.

The exposure of healthy subjects to high altitude represents a model to explore the pathophysiology of diseases related to tissue hypoxia. We explored a plasma metabolomics approach to detect alterations induced by the exposure of subjects to high altitude. Plasma samples were collected from 60 subjects both on plain and at high altitude (5300 m). Metabolite profiling was performed by gas chromatography-mass spectrometry (GC-MS) and ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOFMS) in conjunction with univariate and multivariate statistical analyses. ELISA assays were further employed to measure the levels of several relevant enzymes together with perturbed metabolic pathways. The results showed that hypobaric hypoxia caused significant and comprehensive metabolic changes, as represented by significant changes of 44 metabolites and 4 relevant enzymes. Using MetaboAnalyst 3.0, it was found that several key metabolic pathways were acutely perturbed. In addition, 5 differentially expressed metabolites in pre-exposure samples from the acute mountain sickness-susceptible (AMS-S) group compared with those from the AMS-resistant (AMS-R) group are identified, which warrant further validation as potential predictive biomarkers for AMS-S individuals. These results provide new insights for further understanding the pathophysiological mechanism of early acclimatization to hypobaric hypoxia and other diseases correlated to tissue hypoxia.

Astragalus on the anti-fatigue effect in hypoxic mice.

OBJECTIVE: Astragalus is a traditional Chinese medicine to improve the function of the body. The purpose of this study is to investigate the effect of astragalus on improvement of anti-fatigue capacity in mice under simulated plateau environment. METHODS: Male Kunming mice were randomly divided into the following groups: the control group, astragalus treatment groups in low dosage (LD) (1.0 g/kg·d), mid dosage (MD) (3.0 g/kg·d), and high dosage (HD) (30 g/kg·d). The control group were fed under normoxia environment, and hypoxic mice were fed at a stimulated elevation of 5000 meters. After continuous intragastric administration for 10 days, exhaustive swimming experiment was conducted in the anoxic environment. The swimming time, glucose and lactic acid concentration in blood, glycogen contents in liver, SOD and MDA were determined. RESULTS: Compared with the control group, the swimming time of each astragalus treated group was evidently prolonged (P < 0.05), and the area under the blood lactic acid curve was significantly decreased (P < 0.05). In the high and middle dose of astragalus group, liver glycogen was obviously increased. After exhausted swimming, glycogen contents in blood and SOD were significantly increased, while MDA was evidently reduced (P < 0.05). CONCLUSION: Astragalus can alleviate physical fatigue in mice under simulated plateau environment. It has an obvious anti-fatigue effect and it's worthy of further study.

Over-starvation aggravates intestinal injury and promotes bacterial and endotoxin translocation under high-altitude hypoxic environment.

AIM: To study whether over-starvation aggravates intestinal mucosal injury and promotes bacterial and endotoxin translocation in a high-altitude hypoxic environment. METHODS: Sprague-Dawley rats were exposed to hypobaric hypoxia at a simulated altitude of 7000 m for 72 h. Lanthanum nitrate was used as a tracer to detect intestinal injury. Epithelial apoptosis was observed with terminal deoxynucleotidyl transferase dUTP nick end labeling staining. Serum levels of diamino oxidase (DAO), malondialdehyde (MDA), glutamine (Gln), superoxide dismutase (SOD) and endotoxin were measured in intestinal mucosa. Bacterial translocation was detected in blood culture and intestinal homogenates. In addition, rats were given Gln intragastrically to observe its protective effect on intestinal injury. RESULTS: Apoptotic epithelial cells, exfoliated villi and inflammatory cells in intestine were increased with edema in the lamina propria accompanying effusion of red blood cells. Lanthanum particles were found in the intercellular space and intracellular compartment. Bacterial translocation to mesenteric lymph nodes (MLN) and spleen was evident. The serum endotoxin, DAO and MDA levels were significantly higher while the serum SOD, DAO and Gln levels were lower in intestine (P < 0.05). The bacterial translocation number was lower in the high altitude hypoxic group than in the high altitude starvation group (0.47 ± 0.83 vs 2.38 ± 1.45, P < 0.05). The bacterial translocation was found in each organ, especially in MLN and spleen but not in peripheral blood. The bacterial and endotoxin translocations were both markedly improved in rats after treatment with Gln. CONCLUSION: High-altitude hypoxia and starvation cause severe intestinal mucosal injury and increase bacterial and endotoxin translocation, which can be treated with Gln.

p300 expression is induced by oxygen deficiency and protects neuron cells from damage.

Low oxygen level or oxygen deficiency (hypoxia) is a major factor causing neuronal damage in many diseases. Inducing cell adaptation to hypoxia is an effective method for neuroprotection that can be achieved by either inhibiting the death effectors or enhancing the survival factors. Transcription coactivator p300 is necessary for hypoxia-induced transcriptional activation and plays an important role in neuron survival. However, the alteration of p300 expression under hypoxia condition and its role in hypoxia-induced neuronal damage remain unclear. In this study, the distribution of p300 in rat brain and the alteration of its expression in rat hippocampus during hypobaric hypoxia exposure were detected. In addition, the role of p300 in neuronal-like PC12 cell damage induced by oxygen deficiency (3% oxygen) was evaluated. Our results showed that p300 protein was mainly expressed in the cells expressed beta-tubulin III in the cerebral cortex, hippocampus, cerebellum cortex, medulla oblongata and hypothalamus. Less or no positive signal of p300 expression was observed in beta-tubulin III negative cells. This indicated that p300 was predominantly expressed in neurons of rat brain. Furthermore, p300 expression was up-regulated in rat hippocampus during hypoxia exposure and in neuronal-like PC12 cells under 3% oxygen condition. Interestingly, neuronal-like PC12 cell damage induced by oxygen deficiency (3% oxygen) was increased by suppression of p300 expression with short hairpin RNA (shRNA). These data indicate that p300 is an important molecule for neuroprotection under hypoxia.