Effect Of H2 Gas Research Articles

Impact of hydrogen gas inhalation during therapeutic hypothermia on cerebral hemodynamics and oxygenation in the asphyxiated piglet

We previously reported the neuroprotective potential of combined hydrogen (H2) gas ventilation therapy and therapeutic hypothermia (TH) by assessing the short-term neurological outcomes and histological findings of 5-day neonatal hypoxic-ischemic (HI) encephalopathy piglets. However, the effects of H2 gas on cerebral circulation and oxygen metabolism and on prognosis were unknown. Here, we used near-infrared time-resolved spectroscopy to compare combined H2 gas ventilation and TH with TH alone. Piglets were divided into three groups: HI insult with normothermia (NT, n = 10), HI insult with hypothermia (TH, 33.5 ± 0.5 °C, n = 8), and HI insult with hypothermia plus H2 ventilation (TH + H2, 2.1–2.7%, n = 8). H2 ventilation and TH were administered and the cerebral blood volume (CBV) and cerebral hemoglobin oxygen saturation (ScO2) were recorded for 24 h after the insult. CBV was significantly higher at 24 h after the insult in the TH + H2 group than in the other groups. ScO2 was significantly lower throughout the 24 h after the insult in the TH + H2 group than in the NT group. In conclusion, combined H2 gas ventilation and TH increased CBV and decreased ScO2, which may reflect elevated cerebral blood flow to meet greater oxygen demand for the surviving neurons, compared with TH alone.

Fixation of CO2, electron donor and redox microenvironment regulate succinic acid production in Citrobacter amalonaticus

Biological sequestration of CO2 for generating value added products is an emerging strategy. Succinic acid (SA) is an important C4 building block chemical, and its biological production via CO2 sequestration, holds many practical applications. This study presents an in-depth insight on SA production using isolated strain belonging to genus Citrobacter, more closely related to Citrobacter amalonaticus by considering critical process parameters such as different carbon sources at various initial concentrations, buffering agent (NaHCO3) concentrations and different pH conditions. The effect of H2 gas as an electron donor and availability of CO2 during SA production was also evaluated. The results from this work demonstrated that the isolated strain depicted the ability to utilize diverse carbon sources and highest SA production was achieved with sucrose as a substrate, indicating that reduced carbon substrates help in maximizing the redox potential. Incorporation of CO2 and H2 not only enhanced the production of SA but also affected the total acids profile favoring the production of SA over lactic, formic and acetic acids. Additional supply of CO2 and H2 led to maximum SA production of 12.07 gL−1, productivity of 0.36 gL−1 h−1 and SA yield of 48.5%. In control operation when no gases were supplied and in other test conditions where either of the gases were supplied, lactic acid was the major end product followed by acetic acid. The positive effect of CO2 for SA production provides scope for sustainable integration of SA and the CO2-generating biofuel industries or industrial side streams.

Hydrogen gas improves left ventricular hypertrophy in Dahl rat of salt-sensitive hypertension

ABSTRACTPurpose: Hypertension is an important risk factor for death resulting from stroke, myocardial infarction, and end-stage renal failure. Hydrogen (H2) gas protects against many diseases, including ischemia-reperfusion injury and stroke. The effects of H2 on hypertension and its related left ventricular (LV) function have not been fully elucidated. The purpose of this study was to investigate the effects of H2 gas on hypertension and LV hypertrophy using echocardiography.Methods: Dahl salt-sensitive (DS) rats were randomly divided into three groups: those fed an 8% NaCl diet until 12 weeks of age (8% NaCl group), those additionally treated with 2% H2 gas (8% NaCl + 2% H2 group), and control rats maintained on a diet containing 0.3% NaCl until 12 weeks of age (0.3% NaCl group). H2 gas was supplied through a gas flowmeter and delivered by room air (2% hydrogenated room air, flow rate of 10 L/min) into a cage surrounded by an acrylic chamber. We evaluated interventricular septal wall thickness (IVST), LV posterior wall thickness (LVPWT), and LV mass using echocardiography.Results: IVST, LVPWT, and LV mass were significantly higher in the 8% NaCl group than the 0.3% NaCl group at 12 weeks of age, whereas they were significantly lower in the 8% NaCl + 2% H2 group than the 8% NaCl group. There was no significant difference in systolic blood pressure between the two groups.Conclusion: Our findings suggest that chronic H2 gas inhalation may help prevent LV hypertrophy in hypertensive DS rats.

Protective Effects of Hydrogen Gas on Experimental Acute Pancreatitis

Acute pancreatitis (AP) is an inflammatory disease mediated by damage to acinar cells and pancreatic inflammation. In patients with AP, subsequent systemic inflammatory responses and multiple organs dysfunction commonly occur. Interactions between cytokines and oxidative stress greatly contribute to the amplification of uncontrolled inflammatory responses. Molecular hydrogen (H2) is a potent free radical scavenger that not only ameliorates oxidative stress but also lowers cytokine levels. The aim of the present study was to investigate the protective effects of H2 gas on AP both in vitro and in vivo. For the in vitro assessment, AR42J cells were treated with cerulein and then incubated in H2-rich or normal medium for 24 h, and for the in vivo experiment, AP was induced through a retrograde infusion of 5% sodium taurocholate into the pancreatobiliary duct (0.1 mL/100 g body weight). Wistar rats were treated with inhaled air or 2% H2 gas and sacrificed 12 h following the induction of pancreatitis. Specimens were collected and processed to measure the amylase and lipase activity levels; the myeloperoxidase activity and production levels; the cytokine mRNA expression levels; the 8-hydroxydeoxyguanosine, malondialdehyde, and glutathione levels; and the cell survival rate. Histological examinations and immunohistochemical analyses were then conducted. The results revealed significant reductions in inflammation and oxidative stress both in vitro and in vivo. Furthermore, the beneficial effects of H2 gas were associated with reductions in AR42J cell and pancreatic tissue damage. In conclusion, our results suggest that H2 gas is capable of ameliorating damage to the pancreas and AR42J cells and that H2 exerts protective effects both in vitro and in vivo on subjects with AP. Thus, the results obtained indicate that this gas may represent a novel therapy agent in the management of AP.

H 2 Gas Improves Functional Outcome After Cardiac Arrest to an Extent Comparable to Therapeutic Hypothermia in a Rat Model

BackgroundAll clinical and biological manifestations related to postcardiac arrest (CA) syndrome are attributed to ischemia–reperfusion injury in various organs including brain and heart. Molecular hydrogen (H2) has potential as a novel antioxidant. This study tested the hypothesis that inhalation of H2 gas starting at the beginning of cardiopulmonary resuscitation (CPR) could improve the outcome of CA.Methods and ResultsVentricular fibrillation was induced by transcutaneous electrical epicardial stimulation in rats. After 5 minutes of the subsequent CA, rats were randomly assigned to 1 of 4 experimental groups at the beginning of CPR: mechanical ventilation (MV) with 2% N2 and 98% O2 under normothermia (37°C), the control group; MV with 2% H2 and 98% O2 under normothermia; MV with 2% N2 and 98% O2 under therapeutic hypothermia (TH), 33°C; and MV with 2% H2 and 98% O2 under TH. Mixed gas inhalation and TH continued until 2 hours after the return of spontaneous circulation (ROSC). H2 gas inhalation yielded better improvement in survival and neurological deficit score (NDS) after ROSC to an extent comparable to TH. H2 gas inhalation, but not TH, prevented a rise in left ventricular end-diastolic pressure and increase in serum IL-6 level after ROSC. The salutary impact of H2 gas was at least partially attributed to the radical-scavenging effects of H2 gas, because both 8-OHdG- and 4-HNE-positive cardiomyocytes were markedly suppressed by H2 gas inhalation after ROSC.ConclusionsInhalation of H2 gas is a favorable strategy to mitigate mortality and functional outcome of post-CA syndrome in a rat model, either alone or in combination with TH.

Effect of H<sub>2</sub> Gas on Carbon Nanotubes Synthesis

The effect of H2 gas during the carbon nanotubes (CNTs) synthesis with CO-H2 gas mixture was investigated using by mass measurement, and scanning electron microscopy (SEM). The maximum weight and yield of the synthesized carbon (C) were obtained when the mixture ratio of H2:CO was 3:7 and 9:1, respectively. In case of 100% carbon monoxide (CO) without hydrogen (H2) addition, the weight of carbon increased, but CNTs were not observed. The CNTs were formed when the contents of H2 reaches at least 10%, and their structures became more distinct with an increase of H2 addition, and then the shapes of CNTs were more thin and straight. When the contents of H2 was 80% (H2:CO = 8:2), the shapes and growth of CNTs showed an optimal condition. On the other hand, when the contents of H2 was higher than the critical value, the shapes of CNTs became worse due to transition into inactive surface of catalyst. It was found that H2 played a major role in the shapes and structures of CNTs.

H2-assisted control growth of Si nanowires

Large-scale desired silicon nanowires without amorphous silicon oxide sheath have been synthesized by thermal chemical vapor deposition using SiH4 gas at 650°C in a flow mixture of H2 and N2, compared with the short and thick Si nanowires with amorphous SiOx coating obtained in N2. Scanning electron microscopy (SEM), Energy dispersive X-ray spectrometry (EDX) analysis, and high-resolution transmission electron microscopy (HRTEM) have been employed to characterize the Si nanowires. The effects of H2 gas on the catalytic particle size and on the formation of Si nanowires are discussed in detail. Photoluminescence (PL) characteristics further demonstrate the large differences between the H2-assisted grown Si nanowires and the Si nanowires grown in N2.