Hydrogen Sulfide Levels Research Articles

Treatment-resistant schizophrenia: focus on the transsulfuration pathway.

Treatment-resistant schizophrenia (TRS) is a severe form of schizophrenia. The severity of illness is positively related to homocysteine levels, with high homocysteine levels due to the low activity of the transsulfuration pathway, which metabolizes homocysteine in synthesizing L-cysteine. Glutathione levels are low in schizophrenia, which indicates shortages of L-cysteine and low activity of the transsulfuration pathway. Hydrogen sulfide (H2S) levels are low in schizophrenia. H2S is synthesized by cystathionine β-synthase and cystathionine γ-lyase, which are the two enzymes in the transsulfuration pathway. Iron-sulfur proteins obtain sulfur from L-cysteine. The oxidative phosphorylation (OXPHOS) pathway has various iron-sulfur proteins. With low levels of L-cysteine, iron-sulfur cluster formation will be dysregulated leading to deficits in OXPHOS in schizophrenia. Molybdenum cofactor (MoCo) synthesis requires sulfur, which is obtained from L-cysteine. With low levels of MoCo synthesis, molybdenum-dependent sulfite oxidase (SUOX) will not be synthesized at appropriate levels. SUOX detoxifies sulfite from sulfur-containing amino acids. If sulfites are not detoxified, there can be sulfite toxicity. The transsulfuration pathway metabolizes selenomethionine, whereby selenium from selenomethionine can be used for selenoprotein synthesis. The low activity of the transsulfuration pathway decreases selenoprotein synthesis. Glutathione peroxidase (GPX), with various GPXs being selenoprotein, is low in schizophrenia. The dysregulations of selenoproteins would lead to oxidant stress, which would increase the methylation of genes and histones leading to epigenetic changes in TRS. An add-on treatment to mainline antipsychotics is proposed for TRS that targets the dysregulations of the transsulfuration pathway and the dysregulations of other pathways stemming from the transsulfuration pathway being dysregulated.

Association of serum hydrogen sulphide with hypertension and proteinuria in pre-eclampsia

Background: Preeclampsia is a hypertensive disorder of pregnancy affecting multiple systems and characterized chiefly by hypertension and proteinuria in a previously normotensive and non proteinuric women. The main underlying cause for its pathophysiology is an imbalance between the physiological vasoconstrictor and vasodilator molecules in circulation leading to maternal endothelial dysfunction. Hydrogen sulphide (H2S) is a physiological vasodilatory gasotransmitter which plays an important role in the development of hypertension and proteinuria in preeclampsia.
 Aims and Objectives: The aim of this study was to determine the serum level of hydrogen sulphide and spot urinary protein levels in preeclampsia cases and compare it with age matched controls which were normal pregnant women and to find any correlation, if exists, between these two parameters.
 Materials and Methods: Serum level of H2S and spot urinary protein level were measured in one hundred pregnant women with preeclampsia and the values were compared with age matched controls.
 Results: The mean serum H2S level was 32.31 ± 12.62μmol/L in patients which was significantly lower (p<0.001) when compared to controls where mean was 114.50 ±20.35μmol/L. The mean spot urinary protein level was found to be 11.83 ± 5.06 mg/dl in preeclampsia cases which was significantly higher (p<0.001) than in controls where it was 7.18 ± 2.38 mg/dl. A negative correlation was found between the serum level of H2S and both the systolic BP (r=-0.725, p<0.001) and diastolic BP (r= - 0.639, p<0.001) in preeclampsia patients.A negative correlation was also observed between the serum levels of H2S and spot urinary protein in preeclampsia (r=-0.541, p<0.001).
 Conclusion: The present study has elucidated that the serum levels of hydrogen sulphide decreases and the spot urinary protein levels increases in preeclampsia when compared to normal pregnant women and hydrogen sulphide shows a negative correlation with both systolic and diastolic BP in preeclampsia. This study also demonstrates that,there exists a negative correlation between the serum H2S level and spot urinary protein level in preeclampsia patients.

Hydrogen sulfide-mediated resistance against water avoidance stress-induced gastritis by maintenance of gastric microbial homeostasis.

Chronic persistent stress is an important cause of gastritis, but the underlying mechanism remains to be further researched, especially the role of the gastric microbiota in this process. Here, we used the water avoidance stress (WAS) test in mouse models for chronic stress‐induced gastritis to investigate the underlying mechanisms of this disease. The effect of stress on the gastric microbiota was analyzed based on 16S rRNA sequencing; the changes in hydrogen sulfide (H2S) and inflammatory cytokine levels in gastric tissues were detected by Western blotting, ELISA, immunofluorescence, and qRT‐PCR. Hematoxylin and eosin staining was used as an indicator of the gastritis histological score. This finding is consistent with previous studies showing that gastric H2S is negatively associated with the inflammatory index and might protect the gastrointestinal tract from inflammation. WAS‐induced gastritis was associated with a reduction in H2S release, which appeared to affect the homeostasis of the gastric microbiota of mice. Inflammation and microbial dysbiosis were partially reversed by sodium hydrosulfide (NaHS) and vitamin B6 (VB6) supplementation, suggesting the therapeutic potential of VB6 supplementation for the treatment of stress‐induced gastritis. Gastritis has a serious impact on health and quality of life. An increasing number of people are suffering from chronic gastritis linked to a high‐stress lifestyle, and our research provides clues for the prevention and treatment of stress‐induced gastritis.

Expression of nicotinamide adenine dinucleotide phosphate-reduced oxidase-4/reactive oxygen species and cystathionine-γ-lyase/hydrogen sulfide in patients with chronic obstructive pulmonary disease-related pulmonary hypertension

Objective: To observe the levels of serum reactive oxygen species (ROS) and hydrogen sulfide(H(2)S) in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD), and nicotinamide adenine dinucleotide phosphate-reduced (NADPH) oxidase 4 (NOX4) and cystathionine-γ-lyase (CSE) in lung tissue of patients with stable chronic obstructive pulmonary disease (COPD). Methods: (1) A total of 60 patients with AECOPD admitted to the Department of Respiratory Medicine at Ningxia Hui People's Hospital from November 2015 to December 2016 were recruited. According to the results of pulmonary function and echocardiography, the participants were divided into AECOPD-related pulmonary hypertension (PH) group(A) and AECOPD non-PH group (B).Other 30 healthy subjects were selected as the control group (C).Serum ROS and H(2)S of group A, B and C were detected by enzyme-linked immunosorbent assay (ELISA).(2)The lung tissues of patients undergoing lobectomy for lung cancer from November 2012 to April 2017 were collected, who were divided into COPD-related PH group (D), COPD non-PH group (E) and negative control (F). The expression of NOX4 and CSE protein in lung tissue was detected by immunohistochemistry and the thickness of pulmonary arteriole wall was measured. Results: (1)The serum ROS level in group A was higher than group B and C which were (613.52±69.66)IU/ml,(565.76±71.33)IU/ml, (294.63±60.39)IU/ml, respectively with that in group B higher than that in group C (P<0.05). Serum H(2)S level in group A was lower than group B and C, with that in group B lower than group C [(18.59±5.50) nmol/ml, (20.49±4.97) nmol/ml, (38.03±4.43) nmol/ml, respectively P<0.05]. ROS level was positively correlated with pulmonary systolic pressure (PASP) (r=0.59, P<0.05), H(2)S level was negatively correlated with PASP(r=-0.62, P<0.05).(2)The lung tissue expression of NOX4 in group D was higher than group E and F (P<0.05), which were 0.08±0.01,0.06±0.01,0.03±0.01, respectively,while the level of NOX4 in group E was higher than group F (P<0.05). The expression of CSE between group D, E and F were all significantly different (P<0.05),which were 0.03±0.01, 0.07±0.02,0.12±0.02, respectively.(3)Smooth muscle thickness of pulmonary arterioles as a percentage of vascular diameter (WT%) between group D, E and F was all different(P<0.05), which were (40.58±6.63)%,(36.87±5.60)%,(31.27±6.24)%, respectively; so was smooth muscle area of pulmonary arterioles as a percentage of total vascular area(WA%) with (32.33±6.27)%, (30.20±5.28)%, (25.20±4.31)%, respectively (P<0.05). (4)The expression of NOX4 was positively correlated with WT% and WA%, r was 0.81 and 0.66, respectively (P<0.05). The expression of CSE was negatively correlated with WT% and WA%, r was -0.55 and -0.39 respectively (P<0.05). Conclusions: NOX4/ROS and CSE/H(2)S signaling pathways may play an important role in the pathogenesis of COPD related PH.

Biomineralization-Driven Ion Gate in TiO2 Nanochannel Arrays for Cell H2S Sensing.

The level of hydrogen sulfide in the brain and vasculature has long been associated with human health and diseases. Hence, simple and robust analytical tools allowing determination of hydrogen sulfide levels are highly desirable. In this work, a biomineralization-driven ion gate in TiO2 nanochannel arrays for H2S sensing was designed and developed. The formed CuS precipitation decreased the transmembrane current in the presence of bovine serum albumin used as biological mineralizer. Label-free assay for sensing of intracellular S2- was achieved based on changes in ionic current with a detection limit of 56 MCF-7 cells. More importantly, the proposed sensing strategy was promising for reusable application through dissolution of CuS in an acidic media (pH = 1).

Influence of melatonin introduction on the state of glutathione system and the level of hydrogen sulfide in blood of rats with alloxan induced diabetes mellitus

Influence of melatonin introduction on the state of glutathione system and the level of hydrogen sulfide in blood of rats with alloxan induced diabetes mellitus

The correlation between different techniques for the evaluation of oral malodour in children with and without orthodontic treatment.

The aim of this work was to evaluate the correlation between different methods (organoleptic evaluation, gas chromatography, salivary ?-galactosidases activity) for the evaluation of halitosis in children. The secondary purpose was to investigate the influence of orthodontic treatment on halitosis. Study Design: Oral malodour was detected with different methods in 50 children in the Paediatric Dentistry Unit, University of Rome Tor Vergata, Rome, Italy. During the dental visit, level of oral hygiene, tongue coating scores and presence of an orthodontic device, fixed or mobile, were recorded. Two trained and calibrated operators performed the organoleptic evaluation; the Oral ChromaTM device was used for the volatile sulfur compounds (VSCs) quantification and salivary ?-galactosidases (S?-g) activity was evaluated through the spectrophotometric method. The Cohen's Kappa score was used to evaluate the level of agreement between the operators. The Pearson's correlation coefficient was used to evaluate the linear relationship between continuous variables (e.g. S?-g vs. VSCs values) and the Spearman's correlation coefficient was calculated for ordinal variables (e.g. organoleptic scores) vs. other parameters. The LSD test was used to compare the parameters analysed in the study. A positive and significant correlation between the organoleptic evaluation, the S?-g, the levels of hydrogen sulfide (H2S) and methyl mercaptan (CH3SH) was found. The Spearman's correlation has shown that organoleptic scores were significantly correlated with S?-g (0.664, p<0.001) and the Oral ChromaTM measurements of H2S (0.538, p<0.001) and Ch3SH (0.316, p=0.026). The Pearson's correlation showed that S?-g was statistically significantly correlated with the Oral ChromaTM measurements of H2S (0.379 p=0.007) and Ch3SH (0.299, p=0.0035). Stratifying results for orthodontic treatment, it was possible to show that children under orthodontic treatment, both fixed or removable, were characterised by higher level of S?-g. The organoleptic evaluation and Oral ChromaTM measurements showed that children wearing fixed orthodontic were characterised by higher scores. There was a significant correlation between the three different techniques for the evaluation of oral malodour in children. Like in the adult population, the increase of S?-g activity was associated with oral malodour. The presence of fixed orthodontic appliances was correlated to increased scores of all methods for the evaluation of halitosis.

Electrochemical-photoelectrochemical dual-mode sensing platform based on advanced Cu9S8/polypyrrole/ZIF-67 heterojunction nanohybrid for the robust and selective detection of hydrogen sulfide

The detection of hydrogen sulfide by sensing platform is desirable but highly challenged in a single-response mode due to the obstacle of low precision. In this work, a novel dual-mode electrochemical - photoelectrochemical (PEC) sensor based on Cu9S8/polypyrrole/ZIF-67 (Cu9S8/PPy/ZIF-67) nanohybrid as a double signal probe was designed for highly selective detection of hydrogen sulfide. Interestingly, the as-prepared nanohybrid with excellent peroxidase - mimicking activities show remarkable electrocatalytical activity for hydrogen sulfide oxidation by using amperometric i-t. Importantly, another mode of PEC sensing platform was also constructed based on the increase of photocurrent of the modified photoactive electrodes in response to the in-situ generation of cobalt sulfide and oxidation of hydrogen sulfide. This nanohybrid-based dual-signal transduction mode hydrogen sulfide sensor provides a highly selective and relatively wide linear range for real-time tracking hydrogen sulfide levels, which will open a new pathway in bio-sensing system, clinical disease prevention and diagnosis.

Characteristics of pro- and antioxidant processes in blood plasma of patients with chronic renal failure before and after hemodialysis

The aim of the work was to analyze changes of prooxidant and antioxidant processes in blood of patients with chronic renal failure before and after hemodialysis.Material and methods. It was performed the evaluation of pro-and antioxidant processes in plasma of 16 patients with stage 5 of chronic renal failure (CRF) (glomerulonephritis), and 20 donors (comparison group). In blood plasma were determined the levels of oxidatively modified proteins (OMP) and TBA-active products, superoxide dismutase (SOD) and catalase (CAT) activities, the levels of hydrogen sulfide (Н2S) and vitamic С.Results. The imbalance in pro-antioxidant system in plasma of patients with chronic renal insufficiency intensified before the dialysis procedure, as the content of TBA-active products and oxidatively modified proteins in blood plasma of these patients increased on the background of key antioxidant protection enzyme SOD activities and non-enzymatic antioxidants Н2S and vitamin C significant decreasing. After the dialysis procedure, the content of TBA-active products increased, but the level of oxidatively modified proteins almost didn’t change, that pointed to significant degree of degradation of protein molecules. Both SOD and catalase activities and the levels of Н2S and vitamine С were reduced, that pointed to exhaustion of their reserves in patients with chronic renal failure, before and after the dialysis procedure.Conclusions. After hemodialysis the activity of lipoperoxidation processes in blood of patients decreases, that is a favorable prognosis for the stabilization of homeostasis and improvement of the general patients’ condition, but oxidative modification of proteins remains intense, that leads to exhaustion of enzymatic and non-enzymatic antioxidant system reserves.

Correlations between weather parameters, atmospheric hydrogen sulphide level and vitamin B12 administration to H2S exposed workers

Abstract Hydrogen sulphide, a highly toxic gas, can be used in crenotherapy to balance all metabolic processes (minerals, fats and proteins). The main aims of this study were to correlate the weather characteristics with the atmospheric H2S level and to evaluate the antidote activity of B12 Vitamin in the case of prolonged exposure to this compound. 46 volunteers, people from the medical staff of an important Romanian thermal water spring spa, with professional exposure at H2S, were enrolled in this study; numerical data about their blood pressure, atmospheric H2S concentration and about the weather conditions were collected every month for one year. The results indicate an improvement in the blood pressure of volunteers treated with Vitamin B12; no significant correlation between the concentration of total urinary sulphur and the concentration of atmospheric H2S level was found.

Gas Phase Electrodeposition Enabling the Programmable Three-Dimensional Growth of a Multimodal Room Temperature Nanobridge Gas Sensor Array.

Parallel three-dimensional (3D) growth of different nanomaterials with submicrometer resolution is a promising approach to overcome some technological and economic limits encountered in planar integrated homogeneous films. The programmable multimaterial gas phase nanoparticle electrodeposition concept enables the fabrication of a 3D multimodal conductometric gas sensor array. The approach requires the deposition of more than one nanomaterial to achieve orthogonal sensing capabilities and multigas sensitivity and selectivity. The demonstrated "electronic nose"-like array contains 1080 self-aligning 3D nanobridge-based electrical connections of platinum, nickel oxide, and gold on a single chip. The nanobridges form through a nearest neighbor Coulombic interaction. Each gas sensitive bridge is a 3D structure composed of a porous but electrically conducting nanoparticle network. It was found that this architecture is unique, because it does not require external heating to operate. A trimodal sensor array will be demonstrated to detect various levels of ammonia (NH3), carbon monoxide (CO), and hydrogen sulfide (H2S). A 3 × 3 transfer matrix will be discussed to correlate the recorded signals with the gas composition.

Effects of altered maternal folate and vitamin B12 on neurobehavioral outcomes in F1 male mice

Maternal folate and vitamin B12 status during pregnancy may influence development of central nervous system (CNS) in the offspring. Very little attention has been paid to understand the combined effects of both the vitamins during pregnancy. The present study was designed to evaluate the biochemical and behavioral outcomes following alterations in folate and vitamin B12 levels in C57BL/6 mice. The female mice were fed with different combinations of folate and vitamin B12 whereas; males were fed with normal diet for 4 weeks. The mice were mated and the pregnant mice received the same diets as before pregnancy. The F1 male mice were further continued on maternal diet for 6 weeks following neurobehavioral and biochemical assessment. The body weight of the F1 male mice was significantly decreased in the mice that received folate and vitamin B12 deficient diet. Altered cognitive functions were observed in the folate and B12 deficient F1 male mice as assessed by Morris water maze and novel object recognition tests. Spontaneous locomotor activity was decreased in F1 male mice fed with folate and B12 deficient diets. Elevated homocysteine levels and decreased hydrogen sulfide levels were also observed in the brain of F1 male mice on folate and B12 deficient diets. However, GSH and GSSG levels were increased in the brain of the animals supplemented with folate deficient diet with different combinations of B12. The study suggests that exposure of female mice to folate and vitamin B12 deficiency during pregnancy effects in-utero development of fetus, which further leads to behavioral anomalies in adult life and is sufficient to cause impaired cognitive behavior in the subsequent generation. Thus, elucidating the role and importance of maternal dietary folate and B12 ratio during pregnancy.

Acid reactions in hub systems consisting of separate non-reactive CO2 transport lines

Corrosion in carbon steel pipelines is a major threat for safe CO2 transport, and there have been several projects studying the corrosivity of impurities which could be found in captured CO2. Often only two or three of these impurities have been present while performing the experiments. Although these experiments have delivered valuable knowledge, there are still questions of what happens when impurities are present together. Furthermore, several transport pipelines may deliver CO2 to a main pipeline through a hub system for storage or utilization, and while these streams may be safe individually, the blend in the main pipeline could create components that are hazardous for carbon steel.The present study used a novel experimental setup to realistically simulate a CO2 hub. Three individual “pipelines” were joined inside a glass tube in a transparent autoclave. The three “pipelines” were connected to three different reservoir pumps, simulating different capturing sources with dissimilar types of impurities. This gave a mix of low (ppmv) levels of oxygen (O2), sulphur dioxide (SO2), hydrogen sulphide (H2S), nitrogen dioxide (NO2), and water (H2O). Three different experiments were performed with concentrations ranging from 5 to 35 ppmv of the impurities and a total pressure of 100 bar at 25 °C. All impurities were measured before and after the streams were mixed in the autoclave.The experiments revealed that reactions between certain species occured even at concentrations as low as 5 ppmv, but the reaction products were not considered detrimental in terms of corrosion. If the impurity concentrations were increased to about 35 ppmv, acids and solids were produced, and the situation became unacceptable for carbon steel.

Impact of Pharmacological Inhibition of Hydrogen Sulphide Production in the SOD1G93A-ALS Mouse Model.

A number of factors can trigger amyotrophic lateral sclerosis (ALS), although its precise pathogenesis is still uncertain. In a previous study done by us, poisonous liquoral levels of hydrogen sulphide (H2S) in sporadic ALS patients were reported. In the same study very high concentrations of H2S in the cerebral tissues of the familial ALS (fALS) model of the SOD1G93A mouse, were measured. The objective of this study was to test whether decreasing the levels of H2S in the fALS mouse could be beneficial. Amino-oxyacetic acid (AOA)—a systemic dual inhibitor of cystathionine-β-synthase and cystathionine-γ lyase (two key enzymes in the production of H2S)—was administered to fALS mice. AOA treatment decreased the content of H2S in the cerebral tissues, and the lifespan of female mice increased by approximately ten days, while disease progression in male mice was not affected. The histological evaluation of the spinal cord of the females revealed a significant increase in GFAP positivity and a significant decrease in IBA1 positivity. In conclusion, the results of the study indicate that, in the animal model, the inhibition of H2S production is more effective in females. The findings reinforce the need to adequately consider sex as a relevant factor in ALS.

EFFECTS OF LEUCAS CEPHALOTES EXTRACT ON INSULIN RESISTANCE AND ASSOCIATED METABOLIC SYNDROME IN TYPE II DIABETIC RATS

Background: Type II diabetes is the most common metabolic disorder caused by inadequate insulin secretion by pancreatic β-cells to compensate for insulin resistance in peripheral tissues, which leads microvascular and macrovascular complications. Novel treatment strategies for the management of insulin resistance and associated metabolic syndromes, plant based medicines contributing much with minimal side effects like lactic acidosis. Objective: As Insulin resistance and associated metabolic syndrome contributes to the pathogenesis of type 2 diabetes mellitus, we investigated whether methanolic extract of whole plant Leucas cephalotes (MELC) plays any role in preventing type-2 diabetes mellitus and associated metabolic syndrome in streptozotocin (STZ) induced diabetic rats. Materials and Methods: The MELC was prepared by solvent extraction procedure. Rat pups of age 5 days were divided into 4 groups, with 6 animals in each. Group-I pups served as vehicle control and received 1% sodium carboxy methyl cellulose (CMC), Group-II served as diabetic control and was treated only with single dose of streptozotocin (80mg/kg, i.p), Group-III & Group-IV served as test groups were treated with MELC at doses of 150mg/kg and 300mg/kg respectively for about 45 days after single dose administration of STZ (80mg/kg, i.p). On 30th and 45th day, blood samples were collected from all animals and levels of fasting glucose, fasting insulin, uric acid, Hydrogen Sulphide (H2S), triglycerides and total cholesterol levels in plasma were estimated. Results: The plasma fasting glucose levels were found to be significantly (p<0.001) elevated in single dose streptozotocin treated diabetic control than vehicle control. However, in low dose and high dose test groups, fasting glucose levels, fasting insulin levels, insulin resistance, all the biochemical parameters associated with metabolic syndrome such as fasting insulin values, Triglyceride, Total cholesterol, H2S and Uric acid levels were significantly (p<0.01and p<0.001) decreased after chronic administration of MELC for 45 days and the decrease was more prominent with higher dose. Conclusions: The present investigation reveals that MELC administration shows significant effect on insulin resistance and associated metabolic syndrome in a dose dependent manner. So, hereby the beneficial action of MELC on human type-II diabetes may be suggested. Keywords: Leucas cephalotes; Insulin resistance; metabolic syndrome; Streptozotocin; Type-2 Diabetes mellitus.

Hydrogen Sulfide in the Physiological Processes of Jawless Cyclostomes and Jawed Fishes

This review summarizes data on the involvement of hydrogen sulfide as an active signal molecule in the physiological processes of jawless cyclostomes and jawed fishes, which are the most ancient members of vertebrates, and its interaction with the hypoxia factor in an aquatic habitat. The characteristics of the adaptation of jawed fishes to an increased level of hydrogen sulfide are discussed.

The interrelationship between gasotransmitters and lead-induced renal toxicity in rats

This study explored the role of gasotransmitters in lead-induced nephrotoxicity. Long-term exposure of rats to lead resulted in its accumulation in kidney. The accumulated metal impaired kidney function and structure. Lead intoxication resulted in oxidative stress, inflammation and apoptosis in kidney. In addition, it resulted in nitric oxide (NO) overproduction and decrease in hydrogen sulfide (H2S) level and heme oxygenase (HO-1) concentration in kidney. Inhibition of NO overproduction by L–N(G)-nitroarginine methyl ester (L–NAME) and increasing of H2S level by sodium hydrosulfide (NaHS) and CO level by carbon monoxide-releasing molecule-A1 (CORM-A1) inhibited lead-induced impairment of kidney function and structure. These agents inhibited lead-intoxication induced oxidative stress, inflammation, apoptosis, nitrosative stress and reduction of H2S level and HO-1 concentration. Also, concomitant treatment with these agents inhibited lead intoxication-induced increase in protein expressions of inducible NO synthase (iNOS), tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β) and caspase-3 as well as decrease in protein expressions of HO-1 and cystathionine- γ-lyase (CSE) in kidney. The NO donor, L-arginine and the H2S and CO biosynthesis inhibitors, trifluoro-DL-alanine and zinc deutroporphyrin, respectively produced opposite effects and aggravated the toxic effects of lead. These results demonstrate, for the first time, that gasotransmitters play an important role in lead-induced nephrotoxicity.

Comprehensive analysis of how experimental parameters affect H2S measurements by the monobromobimane method

A rapidly increasing number of studies report on widespread biological functions for endogenous hydrogen sulfide. However, the use of multiple, chemically distinct analytical methods to measure free hydrogen sulfide levels in biological samples accumulate data that are not in agreement with each other. In this work a widely appreciated technique, the monobromobimane method, was thoroughly investigated with the overall aims i) to demonstrate how results obtained by different versions of the method should be interpreted and ii) to provide an easy protocol for the community in order to obtain reliable and comparable results. We demonstrate that none of the previously published versions of the method measure free sulfide concentrations in blood serum or plasma samples due to significant interferences with the biomolecule-bound sulfide pool. On the other hand, we stress the biological relevance of these measurements in cases in which they are carefully conducted. To aid future studies, we extensively investigated the entire procedure from sample withdrawal through handling and storing of injection-ready samples until the detection protocol in order to pinpoint all parameters that can affect the final readouts. Based on our rigorous analytical investigations a set of recommendations were compiled that are necessary to ensure reliable, reproducible and comparable results in the field and a detailed standardized protocol is provided.

Effects of hydrogen sulfide on carbohydrate metabolism and blood pressure in obese type‐2 diabetic rats

AimDiabetes is associated with altered endogenous hydrogen sulfide levels, which plays an important role in regulating glucose homeostasis. Here we report on the long‐term effects of sodium hydrosulfide (NaSH) administration on carbohydrate metabolism in obese type 2 diabetic rats.MethodType‐2 diabetes was established using high fat‐low dose streptozotocin. Rats were treated for 9 weeks with intraperitoneal injections of NaSH (0.28, 0.56, 1.6, 2.8, and 5.6 mg/kg) or vehicle. Serum fasting glucose was measured weekly for one month and then at the end of the study. Fasting serum insulin was measured before and after the treatment. At the end of the study, glucose tolerance, pyruvate tolerance, and insulin secretion were determined and blood pressure was measured.ResultsIn diabetic rats, NaSH at 1.6–5.6 mg/kg increased serum glucose and decreased serum insulin; NaSH at 0.28 and 0.56 mg/kg had no effect on these parameters. High doses of NaSH in diabetic rats decreased glucose and pyruvate tolerance as well as insulin secretion; 0.28 mg/kg had no effect, 0.56 mg/kg improved glucose tolerance but not pyruvate tolerance and insulin secretion. Diabetic rats had higher BP than controls; all doses of NaSH decreased blood pressure in these cohorts. In controls, NaSH (5.6 mg/kg) decreased insulin secretion as well as glucose and pyruvate tolerance, while increased serum glucose. NaSH at 1.6–5.6 mg/kg decreased blood pressure in controls.ConclusionIn diabetic rats high doses of NaSH increased serum glucose level, decreased serum insulin and impaired glucose and pyruvate tolerance, a low dose decreased serum glucose during glucose tolerance. NaSH decreased blood pressure at all doses.Support or Funding InformationKK: Supported in part by the National Institutes of Health [R24DA018055; R01GM123508]. SG, SJ, AG: Supported in part by Shahid Beheshti University of Medical Sciences[grant No. 1396/D/93065], Tehran, Iran.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Periodic deprivation of gaseous hydrogen sulfide affects the activity of the concrete corrosion layer in sewers

Sulfide induced concrete corrosion significantly reduces the service life of the sewer systems. Gaseous hydrogen sulfide (H2S) levels are a key factor affecting the corrosion rate and these fluctuate due to the diurnal flow pattern of sewers. Currently, there is little known about how such fluctuations, in particular the periodic deprivation of H2S, may affect the corrosion activity. This study investigated the impact of the deprivation of H2S on the sulfide uptake rate (SUR) of concrete coupons incubated in laboratory corrosion chambers. After systematic evaluation of the gaseous H2S concentration profiles of two sewer systems, two types of profiles, i.e. short- (1 h) and long- (12 h) term deprivation of H2S, were applied to the concrete coupons. In comparison to the baseline SUR, exposing the concrete coupon to 0 ppm of H2S for 1 h consistently caused a temporary increase of the SUR (i.e. 3.2%–12.5%) following re-supply of H2S at baseline levels. With the continuous re-supply of H2S, there was gradual and steady decrease of SUR to the level close to the baseline SUR. However, for the case after deprivation of H2S for 12 h, the SUR was 5.1% lower than baseline SUR and gradually increased to a level similar to the baseline SUR during the 20–30 min of continuous re-supply of H2S. In addition, the simultaneous deprivation of H2S and O2 for 1 h had negligible impact on the SUR. Further analysis suggests that the historically accumulated intermediates of sulfide oxidation could act as electron donors for sulfide oxidizing bacteria (SOB). The replenishment of the intermediates upon the re-supply of H2S could play a key role in the increase of SUR after short-term deprivation of H2S. However, the activity of SOB could be diminished after long-term deprivation of H2S, although the sulfur intermediates still could be available. Estimating the sulfide uptake by concrete using the SUR of the average H2S concentration could lead to overestimation of the sulfide uptake. There could be more significant overestimation for the case with longer deprivation of H2S.