Nitrous Oxide Levels Research Articles

Exposure control practices for administering nitrous oxide: A survey of dentists, dental hygienists, and dental assistants

ABSTRACTEngineering, administrative, and work practice controls have been recommended for many years to minimize exposure to nitrous oxide during dental procedures. To better understand the extent to which these exposure controls are used, the NIOSH Health and Safety Practices Survey of Healthcare Workers was conducted among members of professional practice organizations representing dentists, dental hygienists and dental assistants. The anonymous, modular, web-based survey was completed by 284 dental professionals in private practice who administered nitrous oxide to adult and/or pediatric patients in the seven days prior to the survey. Use of primary engineering controls (i.e., nasal scavenging mask and/or local exhaust ventilation (LEV) near the patient's mouth) was nearly universal, reported by 93% and 96% of respondents who administered to adult (A) and pediatric (P) patients, respectively. However, adherence to other recommended precautionary practices were lacking to varying degrees, and were essentially no different among those administering nitrous oxide to adult or pediatric patients. Examples of work practices which increase exposure risk, expressed as percent of respondents, included: not checking nitrous oxide equipment for leaks (41% A; 48% P); starting nitrous oxide gas flow before delivery mask or airway mask was applied to patient (13% A; 12% P); and not turning off nitrous oxide gas flow before turning off oxygen flow to the patient (8% A; 7% P). Absence of standard procedures to minimize worker exposure to nitrous oxide (13% of all respondents) and not being trained on safe handling and administration of nitrous oxide (3%) were examples of breaches of administrative controls which may also increase exposure risk. Successful management of nitrous oxide emissions should include properly fitted nasal scavenging masks, supplemental LEV (when nitrous oxide levels cannot be adequately controlled using nasal masks alone), adequate general ventilation, regular inspection of nitrous oxide delivery and scavenging equipment for leaks, availability of standard procedures to minimize exposure, periodic training, ambient air and exposure monitoring, and medical surveillance.

Nitrous Oxide and Methane Fluxes from Smallholder Farms: A Scoping Study in the Anjeni Watershed

While agricultural practices are widely reported to contribute to anthropogenic greenhouse gas (GHG) emissions, there are only limited measurements available for emission rates in the monsoon climate of the African continent. We conducted a scoping study to measure nitrous oxide (N2O-N) and methane (CH4) emission rates from 24 plots constructed on smallholder agricultural farms along the slope catena of three transects in the sub-humid Anjeni watershed in the Ethiopian highlands. Greenhouse gas flux samples were collected in 2013, before, towards the end, and after the rainy monsoon phase. At each location, three plots were installed in groups: two plots grown with barley (one enriched with charcoal and the other without soil amendment) and lupine was grown on the third plot without any soil amendment. Preliminary study results showed that nitrous oxide emission rates varied from −275 to 522 μg·m−2·h−1 and methane emissions ranged from −206 to 264 μg·m−2·h−1 with overall means of 51 and 5 μg·m−2·h−1 for N2O-N and CH4, respectively. Compared with the control, charcoal and lupine plots had elevated nitrous oxide emissions. Plots amended with charcoal showed on average greater methane uptake than was emitted. While this study provides insights regarding nitrous oxide and methane emission levels from smallholder farms, studies of longer durations are needed to verify the results.

Modelling levels of nitrous oxide exposure for healthcare professionals during EMONO usage.

BackgroundComputational fluid dynamics (CFD) has been used to compute nitrous oxide (N2O) levels within a room during the administration of an equimolar mix of N2O/oxygen (EMONO) in the clinical setting. This study modelled realistic scenarios of EMONO usage in hospital or primary care, in order to estimate the potential N2O exposure of healthcare professionals (HCP) with routine EMONO use and to provide guidance for EMONO users.MethodsSixteen scenarios were defined by carrying out a survey of practitioners. CFD simulations were performed for each scenario and N2O concentrations over time were calculated. N2O exposures (time-weighted average of concentration over 8 h [TWA-8 h]) were calculated at the HCPs’ mouth to be compared with a predefined occupational exposure limit (OEL).ResultsAdministration duration and ventilation type were the main factors influencing N2O levels; ventilation type also influenced wash-out time between EMONO administrations. N2O concentration showed a plume distribution towards the ceiling and was highly heterogeneous, highlighting the importance of measurement location. Although estimated TWA-8 h varied widely, 13 of the 16 scenarios had an N2O TWA-8 h of <100 parts per million.ConclusionsData demonstrate that EMONO usage in well ventilated rooms – as recommended – helps to ensure that N2O exposure does not exceed the OEL and does not signal any major risks for HCPs when recommendations are followed. Although these data are numerical simulations and should be considered as such, they can provide guidance for EMONO users.

Antidepressant-like effect of the saponins part of ethanol extract from SHF

Ethnopharmacological relevanceSuanzaorenhehuan Formula (SHF) has been used for treating depression-like disorders for many years in China. The saponins part of the SHF (SSHF) extract was the antidepressant effective component. Aim of studyTo investigate the antidepressant-like effect of SSHF and its possible mechanisms. Materials and methodsExperimental approaches including the forced swim test (FST), the tail suspension test (TST) and unpredictable chronic mild stress (UCMS) were used to evaluate the effects of SSHF. The possible mechanisms were explored by measuring monoamine neurotransmitter in mice frontal cortex and hippocampus, testing monoamine oxidase enzyme (MAO) activities, antioxidant enzyme activities and free radicals levels in the brains of UCMS-exposed mice. ResultsThe results showed that SSHF (10, 20, 40mg/kg) significantly decreased the immobility period in FST and TST in mice after two-week treatment. Whereas, SSHF had no significant effect on locomotor activity in mice. It was also found that the serotonin (5-HT) and noradrenaline (NE) levels in the hippocampus and frontal cortex were significantly increased only in 40mg/kg SSHF treated mice. In addition, SSHF (10, 20, 40mg/kg) significantly inhibited monoamine oxidase-A (MAO-A) and monoamine oxidase-B (MAO-B) after 21-day UCMS exposure. SSHF (10, 20, 40mg/kg) significantly decreased the nitrous oxide (NO) levels, and increased the activities of total antioxidant capability (T-AOC), glutathione peroxidase (GSH-PX), and catalase (CAT) in different degrees in the brains of UCMS-exposed mice. ConclusionsOur results suggested that SSHF may effectively produce an antidepressant-like effect, which appeared to involve the serotonergic, noradrenergic, monoamine oxidase enzyme and antioxidant systems.

Assessment of ADMA, estradiol, and progesterone in severe preeclampsia

ABSTRACTBackground: Decreased nitrous oxide (NO) levels are crucial factors in severe preeclampsia (sPE), and asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of NO synthetase. Steroid hormones are closely related to the vascular endothelium. This study determined the levels of and correlations between ADMA, estradiol (E2), and progesterone (Pg) in sPE to investigate the roles of these factors in this disease. Methods: Sixty-two sPE patients (sPE group) were divided into the sPE1 subgroup (28+1–32+0 weeks of pregnancy), the sPE2 subgroup (32+1–36+0 weeks), and the sPE3 subgroup (36+1–40+0 weeks) and 75 normal pregnant women (NC group) were divided into the NC1 subgroup (28+1–32+0 weeks of gestation), the NC2 subgroup (32+1–36+0 weeks), and the NC3 subgroup (36+1–40+0 weeks). Serum and placental ADMA levels were measured by enzyme-linked immunosorbent assay (ELISA), and serum E2 and Pg concentrations were determined by the chemilumineseent immunoassay (CLIA). Results: ADMA concentrations in both the placenta and the maternal serum were significantly higher in the sPE group (p < 0.05). Higher ADMA contents were observed in the placenta relative to the maternal serum (p < 0.05). Serum E2 levels were significantly lower in the sPE group (p < 0.05). For Pg, the only significant difference was observed between the sPE1 and NC1 subgroups (p < 0.05). The Pg/E2 ratios in the sPE groups were significantly higher, with a significant high positive correlation between Pg/E2 ratios and serum ADMA levels. Conclusion: Increased serum levels of ADMA in sPE may result from increased secretion from the placenta, and the increased Pg/E2 ratio may play a role in the development of sPE by aggravating ADMA.

Bifunctional H2WO4/TS-1 catalysts for direct conversion of cyclohexane to adipic acid: Active sites and reaction steps

Adipic acid production may account for 10% of the annual increase in atmospheric nitrous oxide level. Here we developed a hollow H2WO4/TS-1 bifunctional catalyst with excellent catalytic activity for the direct transformation of cyclohexane to adipic acid with 30% hydrogen peroxide by a non-HNO3 route. XRD diffraction, N2 physisorption, TEM, NH3-TPD and Raman, XPS, Infrared, and UV–visible spectroscopies were used to characterize catalysts to increase understanding of the structure of active species on the hollow TS-1 support. The enhanced catalytic activity in comparison of reference catalysts (H2WO4, H2WO4/Silicate-1 and TS-1) was explained in terms of their bifunctional catalytic sites and perfect hollow morphology with large intraparticle voids. Experimental results on the product distribution indicated that the tetrahedral Ti and surface W sites played important roles in the synergistic effect: tetrahedral Ti worked in oxidation of cyclohexane to intermediates (cyclohexanone and cyclohexanol) and surface W worked in further oxidation of late intermediates to adipic acid. Theoretical calculation results on catalytic activity of the TiOOH and WOOH active sites in the H2WO4/TS-1 for different reaction steps validate the experimental results. The catalytic activity was also correlated to the strong interaction between W sites and HTS-1 surface induced increase in acidity of the materials. Increasing calcination temperature led to structural evolution of supported active species and subsequent activity change. A cyclohexane conversion of 31% with 78% adipic acid selectivity was achieved over this catalyst calcinated at 500 ∘C. Based on the catalytic and characterization results, possible reaction pathways were thus proposed to explain high adipic acid yield over hollow H2WO4/TS-1 catalysts.

Pathways and key intermediates required for obligate aerobic ammonia-dependent chemolithotrophy in bacteria and Thaumarchaeota

Chemolithotrophic ammonia-oxidizing bacteria and Thaumarchaeota are central players in the global nitrogen cycle. Obligate ammonia chemolithotrophy has been characterized for bacteria; however, large gaps remain in the Thaumarchaeotal pathway. Using batch growth experiments and instantaneous microrespirometry measurements of resting biomass, we show that the terrestrial Thaumarchaeon Nitrososphaera viennensis EN76(T) exhibits tight control over production and consumption of nitric oxide (NO) during ammonia catabolism, unlike the ammonia-oxidizing bacterium Nitrosospira multiformis ATCC 25196(T). In particular, pulses of hydroxylamine into a microelectrode chamber as the sole substrate for N. viennensis resulted in iterative production and consumption of NO followed by conversion of hydroxylamine to nitrite. In support of these observations, oxidation of ammonia in growing cultures of N. viennensis, but not of N. multiformis, was inhibited by the NO-scavenger PTIO. When based on the marginal nitrous oxide (N2O) levels detected in cell-free media controls, the higher levels produced by N. multiformis were explained by enzyme activity, whereas N2O in N. viennensis cultures was attributed to abiotic reactions of released N-oxide intermediates with media components. Our results are conceptualized in a pathway for ammonia-dependent chemolithotrophy in Thaumarchaea, which identifies NO as an essential intermediate in the pathway and implements known biochemistry to be executed by a proposed but still elusive copper enzyme. Taken together, this work identifies differences in ammonia-dependent chemolithotrophy between bacteria and the Thaumarchaeota, advances a central catabolic role of NO only in the Thaumarchaeotal pathway and reveals stark differences in how the two microbial cohorts contribute to N2O emissions.

Assessment of N2O Emission Factor of Autumn Chinese Cabbage Fields at Three Different Geographical Location in South Korea

The level of nitrous oxide (N₂O), a long-lived greenhouse gas, in atmosphere has increased mainly due to anthropogenic sources, especially application of nitrogen fertilizers. Quantifying N₂O emission in the agricultural field is essential to develop national inventories of greenhouse gases (GHGs) emission. The objective of this study was to develop an emission factor to estimate the direct N₂O emission from an agricultural field cultivated with the Chinese cabbage during autumn season in 2010-2012. Emission factor of N₂O calculated over three years experiment using accumulated N₂O emission, nitrogen fertilization rate, and background N₂O emission was 0.0058±0.00254 kg N₂O-N kg -1 N. More extensive studies need to be conducted to develop N₂O emission factors for other upland crops in the various regions of Korea because N₂O emission is influenced by many factors including climate characteristics, soil properties, and agricultural practices as well as crop species.

5,7-Dihydroxy-3,4,6-Trimethoxyflavone Attenuates Ischemic Damage and Apoptosis in Mouse Islets

BackgroundThe transplantation of isolated pancreatic islets is a promising treatment for diabetes. 5,7-dihydroxy-3,4,6-trimethoxyflavone (Eupatilin), a pharmacologically active flavone derived from the Artemisia plant species, has been reported to have antioxidant and anti-inflammatory activities. This study examines the hypothesis that preoperative eupatilin treatment can attenuate ischemic damage and apoptosis before islet transplantation. MethodsIslets isolated from Balb/c mice were randomly divided into 2 groups, and cultured in medium supplemented with or without eupatilin. In vitro islet viability and function were assessed. After treatment with a cytokine cocktail consisting of tumor necrosis factor (TNF)-α, interferon (INF)-γ, and interleukin (IL)-1β, islet cell viability, function, and apoptotic status were determined. The glutathione (GSH) and nitrous oxide (NO) levels were also measured. Proteins related to apoptosis were analyzed using Western blotting. ResultsThere was no difference in cell viability between the 2 groups. Islets cultured in the medium supplemented with eupatilin showed 1.4-fold higher glucose-induced insulin secretion than the islets cultured in the medium without eupatilin. After treatment with a cytokine cocktail, glucose-induced insulin release and the total insulin content of the islets were significantly improved in eupatilin-pretreated islets compared with islets not treated with eupatilin. Apoptosis was significantly decreased, and GSH levels were elevated in the eupatilin-pretreated group. Cytokine-only treated islets produced significantly higher levels of NO, iNOS, and caspase-3 than islets pretreated with eupatilin before cytokine treatment. ConclusionsThese results suggest that preoperative eupatilin administration enhances islet function before transplantation and attenuates the cytokine-induced damage associated with NO production and apoptosis.

Developing N2O Emission Factor in Red Pepper Fields to Quantify N2O Emission of Agricultural Field

The level of nitrous oxide (<TEX>$N_2O$</TEX>), a long-lived greenhouse gas, in atmosphere has increased mainly due to anthropogenic sources, especially application of nitrogen fertilizers. Quantifying <TEX>$N_2O$</TEX> emission in the agricultural field is essential to develop National inventories of greenhouse gases (GHGs) emission. The objective of this study was to develop emission factor to estimate direct <TEX>$N_2O$</TEX> emission from agricultural field by measuring <TEX>$N_2O$</TEX> emissions in the red pepper cultivating field from 2010 to 2012. Emission factor of <TEX>$N_2O$</TEX> calculated from accumulated <TEX>$N_2O$</TEX> emission, nitrogen fertilization rate, and background <TEX>$N_2O$</TEX> emission was <TEX>$0.0086{\pm}0.00043kg$</TEX> <TEX>$N_2O-N\;kg^{-1}$</TEX> N resulted from three year experiment of the research sites. More extensive studies need to be conducted to develop <TEX>$N_2O$</TEX> emission factors for other upland crops in the various regions of Korea because <TEX>$N_2O$</TEX> emission is influenced by many factors including climate characteristics, soil properties, and agricultural practices.

Biodiesel production, characterization, diesel engine performance, and emission characteristics of methyl esters from Aphanamixis polystachya oil of Bangladesh

This paper presents the prospect of biodiesel derived from Aphanamixis polystachya oil in diesel engine. The study deals with the physicochemical properties of A.polystachya methyl ester (APME) and its blends followed by evaluation of performance and emission characteristics of APME5 and APME10 in a multi-cylinder diesel engine. It has been observed that the properties of biodiesel and its blends are compatible with the ASTM D6751 and ASTM D7467 standards, respectively. It was found that, APME5 and APME10 showed an average 0.9% and 1.81% reduction in torque and 0.9% and 2.1% reduction in brake power (BP), and 0.87% and 1.78% increase in brake specific fuel consumption (BSFC) compared to diesel. In the case of engine emissions, diesel blends of APME gave an average reduction in carbon monoxide (CO) and hydrocarbon (HC) emissions compared to pure diesel. However, APME blends emitted higher levels of nitrous oxide compared to diesel. It was found that APME5 and APME10 could be used as a diesel fuel substitute without any engine modifications.

Sources of variation in home lawn soil nitrogen dynamics.

Urban, suburban, and exurban lawns are an increasingly important ecosystem type in the United States. There is great concern about the environmental performance of lawns, especially nitrate (NO) leaching and nitrous oxide (NO) flux associated with nitrogen (N) fertilizer use. Previous studies of lawn N dynamics have produced conflicting results, with some studies showing high NO leaching and NO flux and others showing lower losses and high retention and cycling of N inputs. We hypothesized that this variation is caused by differences in lawn management and soil properties that control root and soil organic matter (SOM) dynamics that influence N cycling processes. We tested these hypotheses by making measurements of soil NO, root biomass, rates of potential net N mineralization and nitrification, NO flux, and SOM levels in samples from the front and backyards of residential homes in suburban and exurban neighborhoods with contrasting soil types in the Baltimore metropolitan area. There were no differences between front and backyards, between suburban and exurban neighborhoods, or between different soil types. Further, there were no significant relationships between root biomass, SOM, soil NO levels, and NO fluxes. These results suggest that lawns have uniformly high rates of plant productivity that underlies high levels of SOM and N retention in these ecosystems across the Baltimore metropolitan area.

Effect of Mixed Treatment of Urea Fertilizer and Zeolite on Nitrous Oxide and Ammonia Emission in Upland Soil

Ammonia loss from urea significantly hinders efficient use of urea in agriculture. The level of nitrous oxide (<TEX>$N_2O$</TEX>) a long-lived greenhouse gas in atmosphere has increased mainly due to anthropogenic source, especially application of nitrogen fertilizers. There are reports in the literature showing that the addition of zeolite to N sources can improve the nitrogen use efficiency. This study was conducted to evaluate nitrous oxide (<TEX>$N_2O$</TEX>) and ammonia (<TEX>$NH_3$</TEX>) emission by mixed treatment of urea and zeolite in upland crop field. Urea fertilizer and zeolite were applied at different rates to study their effect on <TEX>$N_2O$</TEX> emission during red pepper cultivation in upland soils. The <TEX>$N_2O$</TEX> gas was collected by static closed chamber method and measured by gas chromatography. Ammonia concentration was analyzed by closed-dynamic air flow system method. The total <TEX>$N_2O$</TEX> flux increased in proportion to the level of N application. Emission of <TEX>$N_2O$</TEX> from the field increased from the plots applied with urea-zeolite mixture compared to urea alone. But urea-zeolite mixture treatment reduced about 30% of <TEX>$NH_3$</TEX>-N volatilization amounts. These results showed that the application of urea and zeolite mixture had a positive influence on reduction of <TEX>$NH_3$</TEX> volatilization, but led to the increase in <TEX>$N_2O$</TEX> emission in upland soils.

Subchronic safety evaluation of CMS-1 (a botanical antihypertensive product derived from Semen Cnidium monnieri) in Sprague–Dawley rats and beagle dogs

CMS-1, mainly composed of imperatorin as its active compound, is a partially purified fraction of a Chinese herbal medicine, Semen Cnidium monnieri. CMS-1 has the potential to be further developed as a new treatment for hypertension. Thus, we studied its toxicity in both Sprague–Dawley rats and beagle dogs. Rats (0–900mg/kg/day) and dogs (0–450mg/kg/day) received CMS-1 orally for 30 consecutive days, followed by a 15-day recovery period. The major target organs of CMS-1 toxicity are the GI (inappetence), liver (hepatocellular necrosis, enzyme elevation), thymus (atrophy), cardiovascular (hypotension), changes in ECG T and P waveforms, elevation of nitrous oxide levels and hematological (RBC parameters disturbances) systems. Most treatment-induced adverse effects were reversible or showed a progressive recovery upon discontinuation of the treatment. The No Observed Adverse Effect Level (NOAEL) was 100mg/kg/day for rats and 50mg/kg/day for dogs. This non-clinical study suggests that clinical monitoring of CMS-1 in patients should focus on the gastrointestinal system, blood tests for liver functions, electrolytes, and blood homeostasis, cardiovascular functions, and immune functions.

Metabolic Syndrome and its Impact on Cardiovascular Diseases

Over the past decade, metabolic syndrome has gained recognition as a significant contributor to cardiovascular mortality. Isolated metabolic syndrome, without diabetes mellitus, plays an increasingly essential role in the pathogenesis of Coronary Artery Disease (CAD). The risk factors for metabolic syndrome act synergistically to promote the development of Cardiovascular Disease (CVD); the more the risk factors, the higher the likelihood of developing CVD. Among these risk factors, obesity is the biggest culprit as it leads to an increase in the levels of free fatty acids (FFAs), thereby resulting in insulin resistance. This, in turn, causes impaired intracellular glucose metabolism and consequent production of free radicals that reduce nitrous oxide levels and cause endothelial dysfunction, leading to atherosclerosis. Also, visceral fat, being a source of C-reactive protein, indirectly promotes inflammation and atherosclerosis. However, in certain races, insulin resistance is fairly common, even in non-obese individuals. This implies the possibilities of multiple complex mechanisms at the microcellular level, causing insulin resistance over and above the aforementioned mechanisms occurring due to obesity. In spite of this fact, control of obesity still remains the first line of defense against metabolic syndrome and resulting cardiovascular mortality. Measures like proper diet and physical exercise, and medications such as statins, fibrates, niacin, and ACE inhibitors are the cornerstones of management of metabolic syndrome. Additionally, clinical trials using medications affecting peroxisome proliferator-activated receptors (PPARs) and intestinal enteropeptidases have shown promising results for treatment of metabolic syndrome. Moreover, current research is also focused on the role of adipokines, semicarbazide-sensitive amine oxidase/vascular adhesion protein-1 (SSAO/VAP-1), 5-HT2c receptors, and the LKB1/AMPK pathway in influencing the mechanisms of insulin resistance. In the near future, newly discovered mechanisms and highly potent novel drugs may reduce the prevalence of metabolic syndrome and subsequent cardiovascular mortality.

Nitrous Oxide Emissions from Red Pepper, Chinese Cabbage, and Potato Fields in Gangwon-do, Korea

The level of nitrous oxide (<TEX>$N_2O$</TEX>), a long-lived greenhouse gas, in atmosphere has increased mainly due to anthropogenic source, especially application of nitrogen fertilizers. Quantifying <TEX>$N_2O$</TEX> emission from agricultural field is essential to develop national inventories of greenhouse gases (GHGs) emission. The objective of the study was to develop emission factor to estimate direct <TEX>$N_2O$</TEX> emission from agricultural field in Gangwon-do, Korea by measuring <TEX>$N_2O$</TEX> emissions from potato (Solanum tuberosum), red pepper (Capsicum annum L.), and Chinese cabbage (Brassica campestris L.) cultivation lands from 2009 to 2012. Accumulated <TEX>$N_2O$</TEX> emission was <TEX>$1.48{\pm}0.25kg$</TEX> <TEX>$N_2O-N\;ha^{-1}$</TEX> for red pepper, <TEX>$1.27{\pm}0.27kg$</TEX> <TEX>$N_2O-N\;ha^{-1}$</TEX> for potato, <TEX>$1.49{\pm}0.06kg$</TEX> <TEX>$N_2O-N\;ha^{-1}$</TEX> for Chinese cabbage cultivated in spring, and <TEX>$1.14{\pm}0.22kg$</TEX> <TEX>$N_2O-N\;ha^{-1}$</TEX> for fall Chinese cabbage. Emission factor of <TEX>$N_2O$</TEX> calculated from accumulated <TEX>$N_2O$</TEX> emission, nitrogen fertilization rate, and background <TEX>$N_2O$</TEX> emission was <TEX>$0.0051{\pm}0.0016kg$</TEX> <TEX>$N_2O-N\;ha^{-1}$</TEX> N for cropland in Gangwon province. More extensive study is deserved to be conducted to develop <TEX>$N_2O$</TEX> emission factor for upland crops in Korea through examining the emission factors from various regions and crops because <TEX>$N_2O$</TEX> emission is influenced by many factors including climate characteristics, soil properties, and agricultural practices.

A cancer vaccine based on the marine antimicrobial peptide pardaxin (GE33) for control of bladder-associated tumors

The marine antimicrobial peptide (AMP) GE33, also known as pardaxin, possesses antimicrobial and anticancer properties, and modulates host signaling. GE33 has cytotoxic effects on murine bladder carcinoma (MBT-2) cells. Here, we investigated the potential of GE33 combined with inactivated MBT-2 as a cancer vaccine. The presence of up to 12.5 μg of GE33 did not inhibit the proliferation or endogenous nitrous oxide (NO) levels of RAW264.7 cells. However, the secretion of MCP-1, IL-6, and IL-12 by RAW264.7 cells was affected by GE33. We proceeded to test the effectiveness of the vaccine by immunizing mice at 7, 14, and 21 days of age, and injecting live MBT-2 cells on the 28th day. Tumor growth by the 58th day was attenuated in mice treated with the vaccine, as compared to the control group. Induction of MBT-2 specific-tumor antigens was increased in mice immunized with our vaccine. Furthermore, activation of T-cell receptors, cytotoxic T-cells, and NK cells was enhanced, and these showed high specificity for targeting tumor cells. Finally, immunization controlled excess recruitment of monocytes, lymphocytes, T-helper cells, and NK cells, and decreased the expression of VEGF. This report provides empirical evidence that our GE33-based vaccine enhances antitumor immunity in mice.

The Effect of the Double Mask on Anesthetic Waste Gas Levels During Pediatric Mask Inductions in Dental Offices

A significant portion of office-based general anesthesia for pediatric patients is performed in dental offices and involves mask inductions with inhaled drugs. This can lead to significant pollution with waste gases. We assessed occupational exposure to anesthetic drugs during pediatric general anesthesia in dental offices and assessed the effectiveness of the "double mask." Nine freestanding dental offices had measurements of anesthetic waste gas levels taken before and immediately after implementation of a double-mask system. Levels of nitrous oxide decreased from a median of 40.0 parts per million (ppm; interquartile range [IQR] = 23.0-46.0 ppm, n = 9) to 3.0 ppm, (IQR = 2.3-4.7 ppm, n = 9, P = 0.0055) and exceeded 25 ppm in 0% of the 9 offices (upper 95% confidence limit 34%) when using the double mask. Levels of sevoflurane decreased from a median of 4.60 ppm (IQR = 3.10-7.00 ppm, n = 9) to 0 ppm (IQR = 0-0.39 ppm, n = 9, P = 0.0024) and exceeded 2 ppm in 0% of the 9 offices (upper 95% confidence limit 34%) when using the double mask. We demonstrated in our study that the double-mask system, when used with dental "high-volumes" suctions (high-volume evacuators producing approximately 12 m(3)/h) in freestanding dental offices, was sufficient to decrease the exposure to anesthetic waste gas during pediatric mask induction in at least two thirds of offices when compared with the traditional mask.

Insights into Denitrification in Methylotenera mobilis from Denitrification Pathway and Methanol Metabolism Mutants

We investigated phenotypes of mutants of Methylotenera mobilis JLW8 with lesions in genes predicted to encode functions of the denitrification pathway, as well as mutants with mutations in methanol dehydrogenase-like structural genes xoxF1 and xoxF2, in order to obtain insights into denitrification and methanol metabolism by this bacterium. By monitoring the accumulation of nitrous oxide, we demonstrate that a periplasmic nitrate reductase, NAD(P)-linked and copper-containing nitrite reductases, and a nitric oxide reductase are involved in the denitrification pathway and that the pathway must be operational in aerobic conditions. However, only the assimilatory branch of the denitrification pathway was essential for growth on methanol in nitrate-supplemented medium. Mutants with mutations in each of the two xoxF genes maintained their ability to grow on methanol, but not the double XoxF mutant, suggesting that XoxF proteins act as methanol dehydrogenase enzymes in M. mobilis JLW8. Reduced levels of nitrous oxide accumulated by the XoxF mutants compared to the wild type suggest that these enzymes must be capable of donating electrons for denitrification.

Antioxidant and Anti-Inflammatory Effects of Peanut Skin Extracts

Peanut skins are regarded as a low economic value by-product of the peanut industry; however, they contain high levels of bioactive compounds including catechins and procyanidins, which are known for their health-promoting properties. The in vitro antioxidant activity of peanut skin extracts (PSE) has been reported but the associated anti-inflammatory properties have not been widely examined. This study investigated the anti-inflammatory effects of PSE on the pro-inflammatory enzyme, Cyclooxygenase-2 (COX-2) protein expression, on its downstream product, prostaglandin E2 (PGE2), and on nitrous oxide (NO) levels. Defatted peanut skins were extracted using two aqueous solvent mixtures (50% acetone and 90% ethanol), in order to compare the effects of the two solvent systems on antioxidant and anti-inflammatory properties. PSE antioxidant activity was determined by the hydrophilic oxygen radical absorbance capacity (H-ORAC) assay, while total phenolics were determined by the Folin-Ciocalteu assay and flavan-3-ols and procyanidins were quantified by HPLC. Acetone extracted PSE (A-PSE) exhibited numerically, but not statistically higher H-ORAC and total phenolic values than the ethanol extracted PSE (E-PSE) (1836 μmol Trolox/100 g and 67.9 mg GAE/g, and 1830 μmol Trolox/100 g and 51.8 GAE/g respectively). A-PSE also had higher levels of flavan-3-ols and procyanidins than E-PSE. RAW 264.7 cells were pretreated with 1.0%, 2.5% and 5.0% (v/v) of A-PSE or E-PSE and induced with the inflammatory marker, lipopolysaccharide (LPS) for 12 hours. COX-2 protein expression, measured by Western blotting was significantly (p 2 and NO levels measured by ELISA, were significantly (p < 0.05) decreased with increasing added levels of A-PSE and E-PSE suggesting that A-PSE and E-PSE not also possess similar antioxidant properties, but also exhibit similar anti-inflammatory effects.