Donor Heart Preservation with Hydrogen Sulfide:A Systematic Review and Meta-Analysis

Preclinical studies have shown that postconditioning with hydrogen sulfide (H(2)S) exerts cardioprotective effects against myocardial ischemia-reperfusion injury (IRI). The aim of this study was to appraise the current evidence of the cardioprotective effects of H(2)S against IRI in order to explore the future implementation of H(2)S in clinical cardiac transplantation. The current literature on H(2)S postconditioning in the setting of global myocardial ischemia was systematically reviewed and analyzed, performing meta-analyses. A literature search of the electronic databases Medline, Embase and Cinahl identified 1835 studies that were subjected to our pre-defined inclusion criteria. Sixteen studies were considered eligible for inclusion. Postconditioning with H(2)S showed significant robust effects with regard to limiting infarct size (standardized mean difference (SMD) = −4.12, 95% CI [−5.53–−2.71], p < 0.00001). Furthermore, H(2)S postconditioning consistently resulted in a significantly lower release of cardiac injury markers, lower levels of oxidative stress and improved cardiac function. Postconditioning with slow-releasing H(2)S donors offers a valuable opportunity for novel therapies within cardiac preservation for transplantation. Before clinical implication, studies evaluating the long-term effects of H(2)S treatment and effects of H(2)S treatment in large animal studies are warranted

Crossed molecular beam: I. Photoionization studies of hydrogen sulfide and its dimer and trimer, II. A rotating source crossed molecular beam apparatus

Photoionization efficiency data for H(,2)S(\u27+), S(\u27+) and HS(\u27+) have been obtained in the region 645-1190 (ANGSTROM) using the molecular beam method. The ionization energy of H(,2)S was determined to be 10.4607 (+OR-) 0.0026 eV (1185.25 (+OR-) 0.30 (ANGSTROM)). The observed autoionizing vibrational progressions are tentatively assigned to the Rydberg transitions: 5a(,1) (---\u3e) nsa(,1) (n = 5 and 6) and 2b(,2) (---\u3e) nda(,1) (n = 4 and 5). The internal energy effects and the energetics of the ion-molecule reactions H(,2)S(\u27+) + H(,2)S (---\u3e) S(,2)(\u27+) + 2H(,2), HS(,2)(\u27+) + H(,2) + H, H(,3)S(\u27+) + HS, and H(,3)S(,2)(\u27+) + H have been studied by photoionization of hydrogen sulfide dimers which were synthesized by the molecular beam method. The appearance energy (AE) for H(,3)S(\u27+) from (H(,2)S)(,2) was determined to be 10.249 (+OR-) 0.012 eV (1209.7 (+OR-) 1.5 (ANGSTROM)). This value allows the calculation of the absolute proton affinity for H(,2)S at 0 K to be 167.2 (+OR-) 1.4 kcal/mol. Using the measured ionization energies for (H(,2)S)(,2)(\u27+) (9.596 (+OR-) 0.022 eV) and (H(,2)S)(,3)(\u27+) (0.467 (+OR-) 0.022 eV) and the estimated bonding energies for H(,2)S(.)H(,2)S and (H(,2)S)(,2)(.)H(,2)S(0.05 eV), the bond dissociation energies for H(,2)S(\u27+)(.)H(,2)S and (H(,2)S)(,2)(\u27+)(.)H(,2)S are deduced to be 0.92 (+OR-) 0.04 and 0.18 (+OR-) 0.04 eV, respectively. The AE for H(,3)S(\u27+)(.)H(,2)S from (H(,2)S)(,3) (9.84 (+OR-) 0.04 eV) also makes possible the calculation of the bond dissociation energy for H(,3) H(,3)S(\u27+)(.)H(,2)S to be 0.46 (+OR-) 0.10 eV;In the second part, a unique experimental apparatus is described for crossed neutral-neutral molecular beam studies; a rotating source crossed molecular beam apparatus. Each of the two independently rotatable beam sources is provided with two stages of differential pumping. The present beam source chambers permit any molecular beam crossing angle between 180 and 60 degrees. The detector chamber has three differentially pumped regions, the innermost of which contains the electron bombardment ionizer, quadrupole mass filter, and ion counting system which constitute the detector. This stationary detector chamber permits strong differential pumping in all regions and allows the entire detector to be translated, in vacuo over a distance of (TURN)60 cm beginning (TURN)27 cm from the beam crossing region. A particularly attractive feature of;this flexible design is the expected ease with which techniques utilizing lasers may be incorporated; (\u271)USDOE Report IS-T-1113. This work was performed under Contract W-7405-Eng-82 with the U.S. Department of Energy

Hydrogen sulfide and the vasculature: a novel vasculoprotective entity and regulator of nitric oxide bioavailability?

This is a freely-available open access publication. Please cite the published version which is available via the DOI link in this record.Hydrogen sulfide (H(2)S) is a well known and pungent toxic gas that has recently been shown to be synthesised in man from the amino acids cystathionine, homocysteine and cysteine by at least two distinct enzymes; cystathionine-gamma-lyase and cystathionine-beta-synthase. In the past few years, H(2)S has emerged as a novel and increasingly important mediator in the cardiovascular system but delineating the precise physiology and pathophysiology of H(2)S is proving to be complex and difficult to unravel with disparate findings reported with cell types, tissue types and animal species reported. Therefore, in this review we summarize the mechanisms by which H(2)S has been proposed to regulate blood pressure and cardiac function, discuss the mechanistic discrepancies reported in the literature as well as the therapeutic potential of H(2)S. We also examine the methods of H2S detection in biological fluids, processes for H(2)S removal and discuss the reported blood levels of H(2)S in man and animal models of cardiovascular pathology. We also highlight the complex interaction of H(2)S with nitric oxide in regulating cardiovascular function in health and disease

Some studies on a solid state sulfur probe for coal gasification systems

Measurements on the solid electrolyte cell (Ar + H(2) + H(2)S/CaS + CaF(2) + (Pt)//CaF(2)//(Pt) + CaF(2) + CaS/H(2) + H(2)+Ar) show that the emf of the cell is directly related to the difference in sulfur potentials established at the Ar + H(2) + H(2)S/electrode interfaces. The electrodes convert the sulfur potential gradient across the calcium fluoride electrolyte into an equivalent fluorine potential gradient. Response time of the probe varies from approximately 9 hr at 990 K to 2.5 hr at 1225 K. The conversion of calcium sulfide and/or calcium fluoride into calcium oxide is not a problem anticipated in commercial coal gasification systems. Suggestions are presented for improving the cell for such commercial applications

Hydrogen Sulfide Attenuates Carbon Tetrachloride-Induced Hepatotoxicity, Liver Cirrhosis and Portal Hypertension in Rats

BACKGROUND : Hydrogen sulfide (H(2)S) displays vasodilative, anti-oxidative, anti-inflammatory and cytoprotective activities. Impaired production of H(2)S contributes to the increased intrahepatic resistance in cirrhotic livers. The study aimed to investigate the roles of H(2)S in carbon tetrachloride (CCl(4))-induced hepatotoxicity, cirrhosis and portal hypertension.METHODS AND FINDINGS : Sodium hydrosulfide (NaHS), a donor of H(2)S, and DL-propargylglycine (PAG), an irreversible inhibitor of cystathionine &gamma;-lyase (CSE), were applied to the rats to investigate the effects of H(2)S on CCl(4)-induced acute hepatotoxicity, cirrhosis and portal hypertension by measuring serum levels of H(2)S, hepatic H(2)S producing activity and CSE expression, liver function, activity of cytochrome P450 (CYP) 2E1, oxidative and inflammatory parameters, liver fibrosis and portal pressure. CCl(4) significantly reduced serum levels of H(2)S, hepatic H(2)S production and CSE expression. NaHS attenuated CCl(4)-induced acute hepatotoxicity by supplementing exogenous H(2)S, which displayed anti-oxidative activities and inhibited the CYP2E1 activity. NaHS protected liver function, attenuated liver fibrosis, inhibited inflammation, and reduced the portal pressure, evidenced by the alterations of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), hyaluronic acid (HA), albumin, tumor necrosis factor (TNF)-&alpha;, interleukin (IL)-1&beta;, IL-6 and soluble intercellular adhesion molecule (ICAM)-1, liver histology, hepatic hydroxyproline content and &alpha;-smooth muscle actin (SMA) expression. PAG showed opposing effects to NaHS on most of the above parameters.CONCLUSIONS :&nbsp; Exogenous H2S attenuates CCl4-induced hepatotoxicity, liver cirrhosis and portal hypertension by its multiple functions including anti-oxidation, anti-inflammation, cytoprotection and anti-fibrosis, indicating that targeting H2S may present a promising approach, particularly for its prophylactic effects, against liver cirrhosis and portal hypertension.<br /

Gas emissions, minerals, and tars associated with three coal fires, Powder River Basin, USA.

Ground-based surveys of three coal fires and airborne surveys of two of the fires were conducted near Sheridan, Wyoming. The fires occur in natural outcrops and in abandoned mines, all containing Paleocene-age subbituminous coals. Diffuse (carbon dioxide (CO(2)) only) and vent (CO(2), carbon monoxide (CO), methane, hydrogen sulfide (H(2)S), and elemental mercury) emission estimates were made for each of the fires. Additionally, gas samples were collected for volatile organic compound (VOC) analysis and showed a large range in variation between vents. The fires produce locally dangerous levels of CO, CO(2), H(2)S, and benzene, among other gases. At one fire in an abandoned coal mine, trends in gas and tar composition followed a change in topography. Total CO(2) fluxes for the fires from airborne, ground-based, and rate of fire advancement estimates ranged from 0.9 to 780mg/s/m(2) and are comparable to other coal fires worldwide. Samples of tar and coal-fire minerals collected from the mouth of vents provided insight into the behavior and formation of the coal fires