Molecular hydrogen consumption in the human body during the inhalation of hydrogen gas.

Inhaling or ingesting hydrogen (H2) gas improves oxidative stress-induced damage in animal models and humans. We previously reported that H2 was consumed throughout the human body after the ingestion of H2-rich water and that the H2 consumption rate ([Formula: see text]) was 1.0 µmol/min/m(2) body surface area. To confirm this result, we evaluated [Formula: see text]during the inhalation of low levels of H2 gas. After measuring the baseline levels of exhaled H2 during room air breathing via a one-way valve and a mouthpiece, the subject breathed low levels (160 ppm) of H2 gas mixed with purified artificial air. The H2 levels of their inspired and expired breath were measured by gas chromatography using a semiconductor sensor. [Formula: see text] was calculated using a ventilation equation derived from the inspired and expired concentrations of O2/CO2/H2, and the expired minute ventilation volume, which was measured with a respiromonitor. As a result, [Formula: see text] was found to be approximately 0.7 µmol/min/m(2)BSA, which was compatible with the findings we obtained using H2-rich water. [Formula: see text] varied markedly when pretreatment fasting to reduce colonic fermentation was not employed, i.e., when the subject's baseline breath hydrogen level was 10 ppm or greater. Our H2 inhalation method might be useful for the noninvasive monitoring of hydroxyl radical production in the human body.

Breath hydrogen produced by ingestion of commercial hydrogen water and milk.

OBJECTIVE: To compare how and to what extent ingestion of hydrogen water and milk increase breath hydrogen in adults. METHODS: Five subjects without specific diseases, ingested distilled or hydrogen water and milk as a reference material that could increase breath hydrogen. Their end-alveolar breath hydrogen was measured. RESULTS: Ingestion of hydrogen water rapidly increased breath hydrogen to the maximal level of approximately 40 ppm 10-15 min after ingestion and thereafter rapidly decreased to the baseline level, whereas ingestion of the same amount of distilled water did not change breath hydrogen (p < 0.001). Ingestion of hydrogen water increased both hydrogen peaks and the area under the curve (AUC) of breath hydrogen in a dose-dependent manner. Ingestion of milk showed a delayed and sustained increase of breath hydrogen in subjects with milk intolerance for up to 540 min. Ingestion of hydrogen water produced breath hydrogen at AUC levels of 2 to 9 ppm hour, whereas milk increased breath hydrogen to AUC levels of 164 ppm hour for 540 min after drinking. CONCLUSION: Hydrogen water caused a rapid increase in breath hydrogen in a dose-dependent manner; however, the rise in breath hydrogen was not sustained compared with milk.

Effect of dietary turmeric on breath hydrogen.

Turmeric is widely used in Indian cuisine. The main constituents of turmeric are curcumin and its analogues, which are well-known antioxidant compounds. In the present study, we hypothesized that turmeric in curry might increase bowel motility and activate hydrogen-producing bacterial flora in the colon, thereby increasing the concentration of breath hydrogen. Eight healthy subjects fasted for 12 h and ingested curry and rice with or without turmeric (turmeric knockout curry). Breath-hydrogen concentrations were analyzed every 15 min for 6 h by gas chromatography with a semiconductor detector. Curry with turmeric significantly increased the area under the curve of breath hydrogen and shortened small-bowel transit time, compared with curry not containing turmeric. These results suggested that dietary turmeric activated bowel motility and carbohydrate colonic fermentation.

High-throughput assay of nitric oxide metabolites in human plasma without deproteinization by lab-on-a-chip electrophoresis using a zwitterionic additive.

In order to develop a high-throughput assay for nitric oxide metabolites, nitrite (NO2-) and nitrate (NO3-), in biological fluids, we have investigated the simultaneous determination of them using an electrophoretic lab-on-a-chip (microchip capillary electrophoresis, MCE) technique. In this study, in order to establish an MCE assay process without deproteinization, the addition of a zwitterionic additive into the running buffer to reduce the adsorption of protein onto the surface of channel was investigated. Initially, some zwitterionic additives were investigated by making a comparison of relative standard deviations (RSDs) of the migration times for NO2(-) and NO3(-) on capillary electrophoresis. From the results of our comparison of the RSD values, 2% (w/w) N-cyclohexyl-2-aminoethanesulfonic acid (CHES) was selected. As a result of the application of the running buffer with CHES to the MCE process, the complete separation of NO2(-) and NO3(-) in human plasma without deproteinization was achieved within 1 min. Since the RSD values of the positions of the peaks were less than 2.3%, beneficial reduction effects on MCE were suggested. When we used an internal standard method in order to correct the injection volume, the RSDs of the peak heights and areas were less than 10%, and the correlation coefficients of spiked calibration curves ranging from 0 to 350 microM were 0.999 and 0.997 for NO2(-) and NO3(-), respectively. The limits of detection (S/N=3) were 53 microM for NO2(-) and 41 microM for NO3(-). Moreover, the correlation coefficients in excess of 0.99 between the MCE method and a conventional Griess method were achieved for both NO2(-) and NO3(-). Consequently, the possibility of establishing a high-throughput assay process was obtained by utilizing 2% (w/w) CHES to reduce protein adsorption.

Identification of brominated and chlorinated phenols as potential thyroid-disrupting compounds in indoor dusts.

Our previous study demonstrated that compounds in indoor dusts strongly inhibit thyroxine (T4) binding to the human thyroid hormone transport protein transthyretin (TTR) in vitro. Exposure assessment indicated that house dust is an important medium of exposure of children to TTR-binding compounds when binding potency and dust ingestion rates are high. Here, we used chemical fractionation with in vitro competitive human TTR-binding assay and GC-MS to analyze the TTR-binding compounds in a sulfuric-acid-treated dust extract. 2,4,6-Tribromophenol (TriBPh) and 2,3,4,5,6-pentachlorophenol (PeCPh) were potent TTR-binding compounds in all dust samples. 2,4,6-TriBPh- and 2,3,4,5,6-PeCPh-derived theoretical T4 equivalents (T4EQs), calculated arithmetically from the concentrations and relative potencies, accounted for about 40-70% of experimental T4EQs detected in indoor dusts, indicating that these compounds contributed strongly to the TTR-binding potency of indoor dust. Indoor sources of 2,4,6-TriBPh might be brominated flame retardants currently used in household materials such as electrical appliances. In contrast, the 2,3,4,5,6-PeCPh might be trace evidence of past use in agricultural chemicals and preservatives in indoor or outdoor environments, because its use has been banned since 1990 in Japan. 2,4,6-TriBPh and 2,3,4,5,6-PeCPh are ubiquitous potential thyroid-disrupting compounds in the home and work environments of Japan and other countries.

Case study on changes in exhalation of carbon monoxide and nitrogen oxide in breath and skin gas during 2-day smoking cessation and restart.

It is generally accepted that the breath of current smokers contains higher carbon monoxide (CO) and lower nitric oxide (NO) and that smoking cessation increases NO and decreases CO in breath. However, it remains unknown whether cigarette cessation reversibly changes breath NO/CO levels and how smoking cessation and restart could modify CO/NO-producing abilities in breath and skin gas. In the present case study, a so-called healthy smoker repeatedly performed 2-day smoking cessation and restart. To compare breath and skin exhalation, minute exhalation volumes per body surface of CO (VCO), NO (VNO) and nitrogen oxide (NO(x), VNO(x)) in breath and skin gas were calculated using gas chromatography with a semiconductor sensor, chemiluminescence method and respiro-monitor. We found a rapid decrease of breath VCO during smoking cessation and an increase of breath VCO after restart, insignificant changes in skin VCO, insignificant changes in breath and skin VNO, and significant biphasic and reversible changes in breath and skin VNO(x)/VNO(2) (= VNO(x) - VNO). Dominant NO(x) was NO in breath and NO(2) in skin gas. These results suggested that CO and NO(x) in breath and skin gas could be reversibly and acutely altered during 2-day smoking cessation and restart even in the case of a long-term cigarette smoker.

Dioxin-like and transthyretin-binding compounds in indoor dusts collected from Japan: average daily dose and possible implications for children.

Many researchers are increasingly interested in human exposure to house dust containing household compounds such as polybrominated diphenylethers (PBDEs). Nevertheless, no investigations have addressed the endocrine-disrupting potencies of compounds contained in indoor dust. This study specifically addresses endocrine-disrupting potencies such as dioxin-like activity and human transthyretin (TTR)-binding potencies. Using in vitro bioassays, we investigated these activity levels in indoor dusts. We performed exposure assessments of active compounds that are contained in house dust for subsequent evaluation of house dusts' risks to humans. Dioxin-like and TTR-binding activities in sulfuric acid treatment extracts of house and office dust were investigated using Dioxin-Responsive Chemical-Activated LUciferase gene eXpression assay (DR-CALUX) and TTR-binding assay (in vitro competitive human TTR-binding assay). Dioxin-like activities in indoor dust were 38-1400 pg CALUX-TEQ (2,3,7,8-TCDD equivalent)/g (median 160 pg CALUX-TEQ/g) and TTR-binding potencies were 300-5000 pmol T4EQ (thyroxine (T4) equivalent)/g (median 1000 pmol T4EQ/g), which are higher values than those in other environmental samples, e.g., contaminated sediments. These exposure results suggest that children might be affected by both dioxin-like compounds and TTR-binding compounds via house dust. When the ingestion rate, CALUX-TEQ, and T4EQ for house dust are high, thyroid hormone homeostasis in children may be disrupted.

Degradation pathways of decabromodiphenyl ether during hydrothermal treatment.

The hydrothermal degradation pathways of decabromodiphenyl ether during hydrothermal treatment were investigated. After an initial "Heating time", the reaction runs were carried out at constant temperature (heating to 300 degrees C and keeping temperature) and pressure (8MPa) in a SUS316 stainless steel micro autoclave filled with water. Some decomposition of decabromodiphenyl ether was observed over 200 degrees C, and it was decomposed by more than 99% after 10 min at 300 degrees C. The reactivities of bromine on para and meta substituents were relatively high, while its reactivity on ortho bromine was extremely low. The formations of polybrominated dibenzo-p-dioxins and furans (PBDD/DFs) were observed in the early stages of the reactions at around 300 degrees C. The TCDD toxicity equivalency (TCDD-EQs) of the by-products was determined based on relative potencies (REPs EC(5TCDD)) with the Dioxin-Responsive-Chemical Activated Luciferase gene eXpression (DR-CALUX) bioassays technology. These results indicated that the risk of formation of PBDD/DFs in the hydrothermal degradation of deca-BDE was low, and it would be possible to reduce the TCDD-EQs value by adding some catalyst or alkali, or extending processing time.

Relationship between skin acetone and blood beta-hydroxybutyrate concentrations in diabetes.

BACKGROUND: Acetone is emitted from the skin and acetone concentrations correlate with blood beta-hydroxybutyrate. METHODS: Skin acetone concentrations of 63 patients with diabetes and 32 control subjects were measured by cold trapping followed by gas chromatography. RESULTS: Skin acetone concentrations of patients with diabetes (188+/-17 ppb; mean+/-SE) were significantly higher than those of the control subjects (87+/-10 ppb, p<0.01). There was no significant difference in skin acetone concentrations among patients with diabetes with regard to mode of treatment. Skin acetone concentrations were correlated with blood beta-hydroxybutyrate (r=0.669, p<0.01), blood glucose (r=0.608, p<0.01), and HbA1c (r=0.292, p<0.05) in patients with diabetes. Skin acetone concentration was high (940 ppb) in a patient with diabetic ketoacidosis, and it fell to 80 ppb after insulin therapy. CONCLUSION: Measurement of skin acetone can be used as a screening test for ketoacidosis provided the analytical methods and tools become simpler. Moreover, it could become a marker of diabetic control and of ketone production in diabetes and other ketogenic conditions.

Effects of Hypoxia on Nitric Oxide (NO) in Skin Gas and Exhaled Air.

This study confirmed the effects of hypoxia on nitric oxide (NO) concentrations in skin gas and exhaled air. NO concentrations in skin gas and exhaled air were measured by a chemiluminescence analyzer. Arterial oxygen saturation (SpO2) of the right forefinger was determined using an oxygen saturation monitor. The M ± SEM of NO concentrations in skin gas at 20.93% (control), 15.1% and 14.8% oxygen concentrations were 23.7 ± 3.6, 32.3 ± 4.7 and 36.2 ± 5.2 ppb, respectively. M ± SEM of NO concentrations in exhaled air at 20.93% (control), 15.1%, and 14.8% were 25.0 ± 5.1, 35.01 ± 5.6 and 44.9 ± 7.2 ppb, respectively. There was no significant difference in NO concentration at the absolute value of skin gas and exhaled air between normoxia and hypoxia. But significant increase was found at relative changes in skin gas at 15.1% (p<0.01) and 14.8% (p<0.01) oxygen content compared with control. Significant increase was also found at relative changes in exhaled air at 15.1% (p<0.01) and 14.8% (p<0.01) oxygen content compared with control. In conclusion, we confirmed that exposure to hypoxia elicits an increase in NO concentrations at relative changes of skin gas and exhaled air compared to normoxia.

Identification of ammonia in gas emanated from human skin and its correlation with that in blood.

Identifying and measuring the ammonia gas that emanates from human skin, which we called skin gas, has been achieved using a modified gas chromatographic system with a nitrogen-selective detector (flame-thermoionic detector: FTD). The skin gas is collected with a home-made sampling probe or bag, which is used to cover the skin surface of a subject's wrist, or a finger, for 5 min. It was proved that ammonia was present in skin gas for healthy persons and patients with hepatic disease. The average amounts of ammonia were 1.7 +/- 0.4 and 2.7 +/- 0.8 ng/cm2; furthermore, there was a significant difference between them (p < 0.05). In addition, the ammonia levels present in skin gas were correlated with that in blood (r = 0.64, p < 0.05).

Identification of gas emanated from human skin: methane, ethylene, and ethane.

We investigated whether methane, ethylene and ethane gas can be detected in gas emanating from human skin, which is called skin gas. Skin gas was collected with a homemade stainless-steel trap system, which was cooled with liquid nitrogen, and analyzed with a gas chromatograph fitted with a flame ionization detector (FID). Skin-gas samples were obtained by covering a hand for 30 min with a polyfluorovinyl bag in which pure helium gas was introduced. The bag, the trap system and GC were set up online to avoid any contamination by air. Methane, ethylene and ethane in skin gas were successfully collected at an average amount emanated for 30 min (from ten subjects) of 150 +/- 63, 20 +/- 11 and 17 +/- 8 [mean +/- SD] pg/cm2, respectively.

Remediation of soil contaminated with dioxins by subcritical water extraction.

The effectiveness of subcritical water extraction (SCWE) was examined for removing dioxins from contaminated soil. Most dioxins in the soil sample were reduced at 300 degrees C or more, but decreased dioxin concentrations were also observed at 150 degrees C. After 4 h of extraction, 99.4%, 94.5% and 60% of PCDDs were removed from samples at 350, 300 and 150 degrees C, respectively. It was also determined that degradation of dioxins had occurred, since the sum of dioxins in the soil plus water extracts after the experiments had considerably decreased. This study revealed that pressurizing is not essential for the removal of dioxins. Reduction was complete within 30 min at 350 degrees C; however, it took a much longer time at lower temperatures. The results of addition experiments in which OCDDs were added to different types of soil samples have shown that dechlorination is one of the major reaction pathways. After addition of OCDD to soil samples, experiments were carried out to examine in detail the degradation pathways of PCDDs. The removal rates and congener profiles varied among soil types. Although it was previously assumed that removal rates and congener profiles depended on the chemical components in soil, nonparametric statistical analysis revealed no significant relationship between the rate of reduction and elements present in the soil. It was confirmed from isomer patterns that dechlorination of the 2,3,7,8-positions in PCDDs takes place somewhat faster than for the 1,4,6,9-positions.