Filter blot method: A simple method for measuring 3-nitrotyrosine in proteins of atmospheric particulate matter.

Air pollutants, such as nitrogen dioxide (NO2), ozone (O3), and particulate matter (PM), have been epidemiologically reported to contribute to the onset and exacerbation of asthma. We have previously shown that several proteins in atmospheric PM are allergenic in mouse asthma models and that these proteins are nitrated by atmospheric NO2 and O3 in chemical reactions. Based on these results, the amount of 3-nitrotyrosine (3-NT) in atmospheric PM could be an air pollution marker integrating NO2, O3, and PM. We established a method to measure 3-NT by high-performance liquid chromatography electrochemical detection (HPLC-ECD). Although this method is accurate, it requires a filter treatment process, which is time-consuming and costly for an environmental monitoring tool, in which many samples are measured simultaneously. Therefore, in this study, we investigated a simple immunoblotting method in which atmospheric PM proteins were directly transferred to a polyvinylidene fluoride (PVDF) membrane and measured using an anti-3-NT antibody (the filter blot method). The 3-NT value obtained from this method was significantly correlated (r = 0.809, p < 0.001) with that of the HPLC-ECD method, with a detection power of 0.1 µg/mL for tyrosine nitrated bovine serum albumin equivalents. Multiple regression analysis using the filter blot method showed that the amount of 3-NT in atmospheric PM was significantly associated with the published environmental measurements of O3 and PM in the region. Therefore, the filter blot method may be useful for the environmental monitoring of 3-NT in atmospheric PM.

Periodontal diseases assessed by average bone resorption are associated with microvascular complications in patients with type 2 diabetes.

Periodontal disease often develops in patients with diabetes, and further exacerbated with diabetic complications. It would be clinically important to clarify the relationship between diabetic microvascular diseases and periodontal disease. This study aimed to evaluate the association between periodontal disease and diabetic complications in patients with type 2 diabetes with poor glycemic control. A total of 447 patients with type 2 diabetes hospitalized at Rakuwakai Otowa Hospital, Japan, were initially recruited in this study. After excluding 134 patients who lacked clinical data or were edentulous, 312 were included in our study. The severity of periodontal disease was evaluated based on the average bone resorption rate. Patients with diabetic nephropathy developed severe periodontal disease (multivariate-adjusted odds ratio, 3.00 [95% CI 1.41-5.19]). Diabetic neuropathy was positively associated with the severity of periodontal disease; the multivariate-adjusted odds ratio (95% CI) was 1.62 (0.87‒2.99) for moderate and 4.26 (2.21‒8.20) for severe periodontal disease. In contrast, diabetic retinopathy was linked with moderate periodontal disease (multivariate-adjusted odds ratio 2.23 [95% CI 1.10-4.10]), but not with severe conditions (multivariate-adjusted odds ratio 0.92 [95% CI 0.67-3.07]). In conclusion, periodontal disease, evaluated by average bone resorption rate, was associated with diabetic nephropathy and neuropathy. Supplementary Information: The online version contains supplementary material available at 10.1007/s13340-022-00591-0.

Airborne fine particulate matter in Japan induces lipid synthesis and inhibits autophagy in HepG2 cells.

Inhalation of particulate matter with a diameter less than 2.5 µm has been reported to exacerbates fatty liver disease. However, the components and mechanisms of particulate matter involved in hepatic lipid metabolism and autophagy have not been fully elucidated. We found that atmospheric particulate matter in Japan stimulated lipogenesis in hepatocytes even when its lipid component was removed. Furthermore, we demonstrated that particulate matter did not promote autophagosome formation but inhibited autophagic degradation in hepatocytes. In previous toxicity experiments, particulate matter collected from atmosphere often contained contaminants originating from filters. In this study, we exposed the powdery particulate matter with less contaminants collected using a cyclone and impactor system to HepG2 cells, human hepatocyte. This particulate matter induced lipogenesis and endoplasmic reticulum stress in HepG2 cells as well as previous reports of particulate matter in the USA and China. On the other hand, when autophagic flux were examined in detail, the particulate matter did not promote autophagosome formation, but inhibited autophagic degradation. Since these effects were similar to those of palmitate, a fatty acid, we prepared particulate matter in which lipid component was removed by acetone and compared the effects on HepG2 cells with those of untreated one. The particulate matter without lipid component induced lipid droplets as well as did the untreated one although it induced less endoplasmic reticulum stress. These results suggest that hepatic lipid synthesis is stimulated not only by the uptake of lipid but also by other components in the particulate matter.

SOD2 mRNA as a potential biomarker for exercise: interventional and cross-sectional research in healthy subjects.

The health-promoting effects of exercise are explained by the biological adaptation to oxidative stress via maintenance of mitochondrial function especially in muscles. Although the induction of antioxidant enzymes in muscle is a useful indicator of exercise, it is not widely used due to the invasiveness of muscle biopsies. To explore more suitable biomarkers for exercise, we examined mRNA levels of antioxidant enzymes in peripheral blood mono-nuclear cells of 14 volunteers in an exercise intervention study. These results were validated in a cross-sectional study of 392 healthy individuals, and we investigated the association between exercise habits, smoking, alcohol consumption, mitochondrial DNA, malondialdehyde, and various clinical features. The 2-week exercise increased superoxide dismutase 1 at the end of exercise and superoxide dismutase 2 from week 4 onwards. In the cross-sectional study, superoxide dismutase 2 correlated positively with exercise habits and number of mitochondrial DNA, and negatively with malondialdehyde levels. Multivariate binominal regression analysis showed that superoxide dismutase 2 was positively associated with exercise habits in nonsmoking individuals. These results suggest that mRNA levels of superoxide dismutase 2 in blood might be a potentially useful biomarker for exercise in healthy individuals. This study was registered with University Hospital Medical Information Network (No: 000038034).

Compromised glutathione synthesis results in high susceptibility to acetaminophen hepatotoxicity in acatalasemic mice.

Acatalasemia is caused by genetic defect in the catalase gene. Human achatalasemia patients are able to scavenge physiological hydrogen peroxide but are vulnerable to exogenous oxidative stress. In the present study, we used an acetaminophen-induced hepatotoxicity model in acatalasemic mice to explore this vulnerability. Interestingly, the acetaminophen-induced decrease in total glutathione levels was more prolonged in acatalasemic mice. While the subunits of glutamate-cysteine ligase, a glutathione synthase enzyme, were increased by acetaminophen in the liver of wild-type mice, their expression was lower and was further reduced by acetaminophen in acatalasemic mice. This feature was also observed in immortalized hepatocytes derived from the livers of these mice. However, when catalase was knocked down in HepG2 cells, a cultured human liver cell line, the expression of glutamate-cysteine ligase subunits was increased, suggesting that the low expression of glutamate-cysteine ligase subunits in acatalasemia may be due to other mechanism than catalase deficiency. Therefore, when other factors were investigated, it was found that transforming growth factor-ß1 was up-regulated by acetaminophen in the liver of acatalasemic mice, which may inhibit the expression of glutamate-cysteine ligase subunits. The results of this study suggest a new toxic mechanism of acetaminophen-induced liver injury in patients with acatalasemia.

Possible contribution of hepatocyte secretion to the elevation of plasma exosomal arginase-1 in high-fat diet-fed mice.

AIMS: The elevation of arginase in vascular tissues decreases nitric oxide production, which is considered as an early step of atherosclerosis in obesity. Previously, we found that arginase-1, one of arginase isozymes, was elevated in the blood plasma of obese adults. The purpose of this study is to elucidate the mechanism by which obesity increases arginase-1 levels in the blood. MAIN METHODS: C57/BL6J male mice fed a high-fat diet (HFD) for 12 weeks were analyzed for factors related to nitric oxide/arginine metabolism and plasma exosomes. To explore the arginase secretory organs, the protein expression levels were analyzed in several organs. To further investigate the relationship between exosomal arginase-1 in plasma, blood glucose levels and arginase-1 in the liver, HepG2 (the human hepatoma cell line) was analyzed after treatment with high glucose. KEY FINDINGS: The increase in arginase activity in the plasma of HFD-fed mice was positively corelated with blood glucose levels and was accompanied by an increase in exosomal arginase-1 levels. Among the organs that highly express arginase, the liver of HFD-fed mice showed a significant increase in arginase-1. The expression of arginase-1 in exosomes and total lysates of HepG2 cells were increased by high glucose exposure. SIGNIFICANCE: Increased exosomal arginase-1 in plasma contributes to increased plasma arginase activity in obesity. The liver is a candidate organ for the secretion of exosomal arginase-1 into plasma, and the p38 pathway induced by high glucose levels may be involved.

Antibacterial Effects of Disulfiram in Helicobacter pylori.

BACKGROUND: Helicobacter pylori infection poses a risk of the occurrence of gastrointestinal diseases, such as gastric cancer. Its incidence rate is significantly reduced by eradication, and thereby, eradication therapy is generally performed. Disulfiram is an oral prescription drug mainly used for the treatment of alcohol dependence. In recent years, reports have been made on its anticancer and antibacterial effects, and thus, it has recently become an interesting subject. This study aimed to examine the antibacterial activity of disulfiram, investigate the presence or absence of its antibacterial activity on H. pylori, and determine whether it could be a new bactericidal drug against drug-resistant H. pylori. MATERIALS AND METHODS: Drug-sensitive strains of H. pylori and amoxicillin-resistant, clarithromycin-resistant, and metronidazole-resistant strains were used, and a growth inhibition test of H. pylori using disulfiram was performed. Furthermore, the expression of urease, vacuolating cytotoxin A (VacA), and CagA, the virulence proteins of H. pylori, was quantitatively analyzed using the Western blotting method. In addition, for H. pylori used in this study, the 16SrDNA sequence, a ribosomal gene involved in protein production, was analyzed to examine the presence or absence of gene mutation. RESULTS: Disulfiram suppressed the growth of 7 out of 12 H. pylori strains at 1 µg/mL, and no correlation was observed between their susceptibility/resistance to current eradication antimicrobial drugs and disulfiram resistance. Disulfiram reduced the expression levels of urease, VacA, and CagA proteins. H. pylori, which showed resistance to disulfiram, tended to have fewer gene deletions/insertions in the 16S rDNA sequence; however, no specific mutation was detected. CONCLUSION: Disulfiram has a bactericidal effect on H. pylori at low concentrations, suggesting that it can be used as a supplement for current H. pylori eradication drugs.

Role of HO-1 against Saturated Fatty Acid-Induced Oxidative Stress in Hepatocytes.

Increased circulating levels of free fatty acids, especially saturated ones, are involved in disease progression in the non-alcoholic fatty liver. Although the mechanism of saturated fatty acid-induced toxicity in the liver is not fully understood, oxidative stress may be deeply involved. We examined the effect of increased palmitic acid, the most common saturated fatty acid in the blood, on the liver of BALB/c mice via tail vein injection with palmitate. After 24 h, among several anti-oxidative stress response genes, only heme oxygenase-1 (HO-1) was significantly upregulated in palmitate-injected mice compared with that in vehicle-injected mice. Elevation of HO-1 mRNA was also observed in the fatty liver of high-fat-diet-fed mice. To further investigate the role of HO-1 on palmitic acid-induced oxidative stress, in vitro experiments were performed to expose palmitate to HepG2 cells. SiRNA-mediated knockdown of HO-1 significantly increased the oxidative stress induced by palmitate, whereas pre-treatment with SnCl2, a well-known HO-1 inducer, significantly decreased it. Moreover, SB203580, a selective p38 inhibitor, reduced HO-1 mRNA expression and increased palmitate-induced oxidative stress in HepG2 cells. These results suggest that the HO-1-mediated anti-oxidative stress compensatory reaction plays an essential role against saturated fatty acid-induced lipotoxicity in the liver.

Plasma Arginase-1 Level Is Associated with the Mental Status of Outpatients with Chronic Liver Disease.

While plasma arginase-1 has been suggested as a biomarker of mental status in healthy individuals, it has not been evaluated in patients with chronic liver disease. This cross-sectional study investigated the utility of plasma arginase-1 for screening mental status in patients with chronic liver disease. This study included outpatients with chronic liver disease who underwent regular check-ups at Okayama University Hospital between September 2018 and January 2019. In addition to the standard blood tests, the plasma arginase-1 level was analyzed. The patients' mental status was assessed using the Japanese version of the General Health Questionnaire-28 (GHQ-28). The associations between mental status and various parameters, including plasma arginase-1, were investigated using logistic regression analysis. Among 114 participating patients, 8 were excluded, comprising 6 with insufficient blood samples for plasma arginase-1 measurement and 2 with incomplete questionnaires. Multivariate binomial logistic regression analysis revealed that plasma arginase-1 was significantly and negatively associated with the GHQ-total score, especially somatic symptoms. Therefore, plasma arginase-1 may be a useful biomarker for assessing the mental status of outpatients with chronic liver disease.

Association between Psychological Factors and Evacuation Status and the Incidence of Cardiovascular Diseases after the Great East Japan Earthquake: A Prospective Study of the Fukushima Health Management Survey.

Evidence regarding the effect of psychological factors and evacuation on cardiovascular disease occurrence after large-scale disasters is limited. This prospective study followed up a total of 37,810 Japanese men and women aged 30-89 years from the Fukushima Prefecture with no history of stroke or heart disease at baseline (2012), until 2017. This period included 3000 cardiovascular events recorded through questionnaires and death certificates. The participants' psychological distress, trauma reaction, and evacuation status were defined, and divided into four groups based on combinations of psychological factors and evacuation status. We calculated the hazard ratios and 95% confidence intervals for only psychological, only evacuation, or both of them compared with neither using Cox proportional hazard models. Psychological factors along with evacuation resulted in approximately 5% to 25% higher magnitude of stroke and heart disease risk than psychological factors only among men. Compared to neither, the multivariable hazard ratios of those with both psychological distress and evacuation were 1.75 for stroke and 1.49 for heart disease, and those of both trauma reaction and evacuation were 2.01 and 1.57, respectively, among men. Evacuation combined with psychological factors increased the risk of stroke and heart disease risks especially in men after the Great East Japan Earthquake.

Low Consultation Rate of General Population with Atrial Fibrillation.

In order to prevent ischemic stroke, it is important to identify and treat patients with atrial fibrillation (AF) who do not consult a doctor in a medical institution. The aim of this study was to determine the consultation rate at medical institutions for patients with AF in group medical examinations conducted in a city in western Japan. Of 6101 examinees of group medical examinations (40 years of age or older) conducted in Ibara City, Okayama Prefecture, Japan, from 2012 to 2014, 4338 participants (71.1%) who were evaluated by electrocardiogram (ECG) gave written informed consent and responded to surveys in the form of questionnaires through a personal interview conducted by nurses were included in the Ibara-AF study. A cumulative total of 82 subjects were diagnosed as having AF by ECG (prevalence of AF = 1.89%), and 51 individuals had AF during the three-year period.15 (29.4%) of the 51 patients with AF did not regularly visit medical institutions. Among them, 46.7% (n = 7) and 53.3% (n = 8) of the patients were symptomatic and asymptomatic, respectively, and 73.3% of the patients had a CHADS2 score of more than one point. There were no significant differences in patients' characteristics between regular and non-regular visit groups. In conclusion, about one-third of the patients with AF did not regularly see a doctor in a medical institution and most of them had a CHADS2 score of more than one point in a Japanese rural area. Educating the public about the risks of AF is required.

Human albumin augmented airway inflammation induced by PM2.5 in NC/Nga mice.

The synergic allergic inflammatory effects of particulate matter (PM) 2.5 and human albumin were investigated in NC/Nga mice, which are hypersensitive to mite allergens. PM2.5 or PM2.5 plus human albumin with aluminum oxide was injected twice intraperitoneally for sensitization. After 7 days, PM2.5 or PM2.5 plus human albumin was administered five times intranasally to mice for further sensitization. Subsequently, PM2.5 was administered as a challenge on the 11th day. On the 12th day, mice were examined for airway hyperresponsiveness (AHR), bronchoalveolar lavage fluid (BALF) cell count, mRNA expression of Th1 , Th2 cytokines, chemokines, and mucus proteins (MUC5AC and MUC5B) in the lung tissue and histopathology. Although PM2.5 or human albumin alone did not induce allergic airway inflammation, simultaneous inoculation of PM2.5 and human albumin-induced airway inflammation showing increase in AHR, total BALF cell numbers, mRNA levels of IL-13, eotaxin 1, eotaxin 2, and MUC5AC, and anti-IG against human serum albumin. Inflammation was observed around the bronchus in PM2.5 plus human albumin-induced lungs. These results demonstrate that PM2.5 can induce allergic airway inflammation through the synergistic action with human albumin in NC/Nga mice.

Head cooling during sleep improves sleep quality in the luteal phase in female university students: A randomized crossover-controlled pilot study.

Although selective head-cooling has been reported to decrease scalp and tympanic temperature and improve sleep quality, whether head-cooling during sleep can improve sleep quality in women during the luteal phase has not been elucidated. This randomized, controlled crossover open trial aimed to investigate the effect of head cooling during sleep on sleep quality in women during the luteal phase. Female university students aged 19-25 years with increased daytime sleepiness during the luteal phase were recruited by poster advertisement at their university from May to June 2016 and from May to June 2017. Fourteen women aged 19-22 years participated in this study. The temperature-controllable cooling sheet containing tubes filled with circulating water was used for head-cooling, and the head-cooling and the controlled temperature were set at 25°C and 35°C, respectively. Electroencephalogram data were obtained using a single-channel portable electroencephalogram device. The difference in sleep-related variables and tympanic temperature between head-cooling and control were analyzed using a linear mixed model. The proportion of arousal was lower with head cooling than with the control. In contrast, the proportion of non-REM3 and the delta power were higher with head cooling than with the control. The proportion of non-REM2 and non-REM3 among sleep EEG stages were positively and negatively correlated with the mean tympanic temperature during sleep, respectively. However, arousal and REM were not correlated with tympanic temperature. We considered the reduction of arousal time by head-cooling might be related to scalp temperature rather than tympanic temperature. Further, our results suggested that head-cooling also improved subjective sleep comfort. In conclusion, head-cooling during sleep could improve sleep quality in young women during the luteal phase.

Detection of 3-Nitrotyrosine in Atmospheric Environments via a High-performance Liquid Chromatography-electrochemical Detector System.

3-nitrotyrosine (3-NT) is generated from the tyrosine residue in atmospheric bio-aerosol proteins via a reaction with ozone (O3) and nitrogen dioxide (NO2). Stable 3-NT is a specific marker for oxidative damage and is reported to have a promotive effect to elicit allergies. In the present study, we report the development of a highly sensitive assay to quantify 3-NT in air sampler filters to collect < 2.5 µm of particulate matter (PM2.5) from urban environmental air, including bio-aerosol. In this method, a 6 mm-diameter round hole was cut from the filters of air samplers and mixed with a nonspecific protease cocktail in order to hydrolyze proteins. Protein samples digested to the amino acid level were tested for 3-NT using a high-performance liquid chromatography-electrochemical detector (HPLC-ECD). The maximum 3-NT content was detected in a prefilter for PM of sizes from 4.5 to 7.3 µm, with a detection limit of 1.13 pg/m3.

Association of night eating habits with metabolic syndrome and its components: a longitudinal study.

BACKGROUND: Night time eating is a risk factor for metabolic syndrome and obesity. The aim of this study was to investigate whether dinner immediately before bed, snacks after dinner, or combinations of both were associated with metabolic syndrome and its components in a large Japanese cohort. METHODS: We enrolled 8153 adults aged 40-54 years who participated in specific medical checkups in an Okayama facility from 2009 to 2010 and from 2013 to 2014. Age-adjusted and multivariable-adjusted odds ratios of metabolic syndrome and its components in participants with both night eating habits for an average of 3.9 years were evaluated. The relative excess risk due to interaction (RERI) was utilized to determine the supra-additive interaction of both eating habits on metabolic syndrome and its components. RESULTS: The multivariable-adjusted odds ratio for obesity for those with both eating habits compared to those with neither habit was 2.11 (95% confidence interval [CI], 1.42-3.15) for men and 3.02 (95%CI, 1.72-5.29) for women. Both habits had a supra-additive interaction effect on obesity development in women (RERI, 1.67; RERI%, 85.0; p = 0.058), although this result was not significant. In women, there was an association between eating habits at night and metabolic syndrome, but in men it was unrelated. Both night eating habits were associated with dyslipidemia in men and women. CONCLUSIONS: These findings suggest the need for intervention and awareness among individuals with night eating habits to mitigate further complications.

Association between Occupational Dysfunction and Metabolic Syndrome in Community-Dwelling Japanese Adults in a Cross-Sectional Study: Ibara Study.

The purpose of this study was to investigate the relationship between occupational dysfunction and metabolic syndrome (MetS) and its component factors in community-dwelling Japanese adults (N = 1,514). Self-reported lifestyle behaviors, Classification and Assessment of Occupational Dysfunction (CAOD) scores, and metabolic traits were measured. CAOD levels were divided into tertiles (low, moderate, and high), and their associations with MetS and its components were evaluated through logistic regression analysis. The association of MetS with CAOD was demonstrated in the total number of individuals [OR = 1.92 (95% CI 1.17⁻3.17)] and in older individuals [OR = 1.90 (95% CI 1.04⁻3.46)]. The association of dyslipidemia and CAOD was evident for overweight individuals [OR = 2.08 (95% CI 1.17⁻3.68)]. A higher association of high blood pressure with CAOD was evidenced in younger individuals [OR = 2.02 (95% CI 1.05⁻3.89)] who belonged to the highest-CAOD-score group in comparison to those who registered the lowest-CAOD-score group. The evaluation of MetS and interventions related to its prevention may be more effective if the viewpoint of occupational dysfunction is taken into account.

"Ikigai", Subjective Wellbeing, as a Modifier of the Parity-Cardiovascular Mortality Association　- The Japan Collaborative Cohort Study.

BACKGROUND: Nulliparity is associated with an excess risk of cardiovascular disease (CVD). "Ikigai", subjective wellbeing in Japan, is associated with reduced risk of CVD. The impact of ikigai on the association between parity and the risk of CVD, however, has not been reported.Methods and Results:A total of 39,870 Japanese women aged 40-79 years without a history of CVD, cancer or insufficient information at baseline in 1988-1990, were enrolled and followed until the end of 2009. They were categorized into 7 groups according to parity number 0-≥6. Using Cox regression hazard modeling, the associations between parity and mortality from stroke, coronary artery disease, and total CVD were investigated. During the follow-up period, 2,121 total CVD deaths were documented. No association was observed between parity and stroke and CVD mortality in women with ikigai, but there was an association in those without ikigai. The multivariable hazard ratios of stroke and total CVD mortality for nulliparous women without ikigai vs. those with 1 child were 1.87 (95% CI: 1.15-3.05) and 1.46 (95% CI: 1.07-2.01), respectively, and that for stroke mortality in high parity women without ikigai was 1.56 (95% CI: 1.00-2.45). CONCLUSIONS: Nulliparous or high parity women without ikigai had higher mortality from stroke and/or total CVD, suggesting that ikigai attenuated the association between parity and CVD mortality in Japanese women.

Early obesity leads to increases in hepatic arginase I and related systemic changes in nitric oxide and l-arginine metabolism in mice

Obesity is a risk factor for vascular endothelial cell dysfunction characterized by low-grade, chronic inflammation. Increased levels of arginase I and concomitant decreases in l-arginine bioavailability are known to play a role in the pathogenesis of vascular endothelial cell dysfunction. In the present study, we focused on changes in the systemic expression of arginase I as well as l-arginine metabolism in the pre-disease state of early obesity prior to the onset of atherosclerosis. C57BL/6 mice were fed a control diet (CD; 10% fat) or high-fat diet (HFD; 60% fat) for 8 weeks. The mRNA expression of arginase I in the liver, adipose tissue, aorta, and muscle; protein expression of arginase I in the liver and plasma; and systemic levels of l-arginine bioavailability and NO2 − were assessed. HFD-fed mice showed early obesity without severe disease symptoms. Arginase I mRNA and protein expression levels in the liver were significantly higher in HFD-fed obese mice than in CD-fed mice. Arginase I levels were slightly increased, whereas l-arginine levels were significantly reduced, and these changes were followed by reductions in NO2 − levels. Furthermore, hepatic arginase I levels positively correlated with plasma arginase I levels and negatively correlated with l-arginine bioavailability in plasma. These results suggested that increases in the expression of hepatic arginase I and reductions in plasma l-arginine and NO2 − levels might lead to vascular endothelial dysfunction in the pre-disease state of early obesity

Relationship of particulate matter and ozone with 3-nitrotyrosine in the atmosphere.

The prevalence of allergic diseases has increased in the past few decades. Bio-aerosol proteins and their chemical modifications, such as 3-nitrotyrosine (3-NT), in the atmosphere have been attracting attention due to their promotive effects on allergies. 3-NT is generated from the amino acid, tyrosine, through a reaction with ozone (O3) and nitrogen dioxide (NO2). However, the underlying mechanisms have not yet been elucidated in detail. Therefore, we measured 3-NT and evaluated the relationships among 3-NT and various pollutants such as sulfur dioxide (SO2), NOx (NO + NO2), ozone (O3), PM7, total suspended particulate matter (TSP) containing proteins, humidity, and temperature. 3-NT positively correlated with O3, SO2, humidity, and temperature, and negatively correlated with NOx. A multiple regression analysis showed that 3-NT positively associated with O3, humidity, and PM7. O3 positively associated with 3-NT and PM7, and negatively associated with NOx and humidity. These results suggest that 3-NT is generated from PM proteins through a reaction with O3 under high humidity conditions, and that the measurement of 3-NT is important and useful for the research of O3.

Early obesity leads to increases in hepatic arginase I and related systemic changes in nitric oxide and L-arginine metabolism in mice.

Obesity is a risk factor for vascular endothelial cell dysfunction characterized by low-grade, chronic inflammation. Increased levels of arginase I and concomitant decreases in L-arginine bioavailability are known to play a role in the pathogenesis of vascular endothelial cell dysfunction. In the present study, we focused on changes in the systemic expression of arginase I as well as L-arginine metabolism in the pre-disease state of early obesity prior to the onset of atherosclerosis. C57BL/6 mice were fed a control diet (CD; 10% fat) or high-fat diet (HFD; 60% fat) for 8 weeks. The mRNA expression of arginase I in the liver, adipose tissue, aorta, and muscle; protein expression of arginase I in the liver and plasma; and systemic levels of L-arginine bioavailability and NO2- were assessed. HFD-fed mice showed early obesity without severe disease symptoms. Arginase I mRNA and protein expression levels in the liver were significantly higher in HFD-fed obese mice than in CD-fed mice. Arginase I levels were slightly increased, whereas L-arginine levels were significantly reduced, and these changes were followed by reductions in NO2- levels. Furthermore, hepatic arginase I levels positively correlated with plasma arginase I levels and negatively correlated with L-arginine bioavailability in plasma. These results suggested that increases in the expression of hepatic arginase I and reductions in plasma L-arginine and NO2- levels might lead to vascular endothelial dysfunction in the pre-disease state of early obesity.