2,4-dinitrophenyl ether-containing chemodosimeters for the selective and sensitive 'in vitro' and 'in vivo' detection of hydrogen sulfide

[EN] Four probes (i.e. D1¿D4) for the selective and sensitive fluorogenic detection of HS2 have been prepared and characterised. HEPES (10 mM, pH 7.4)¿DMSO 99:1 v/v solutions of D1¿D4 are essentially non-fluorescent. Changes in the emission using D1¿D4 in the presence of anions (F2, Cl2, Br2, I2, N2 3 , CN2, SCN2, AcO2, CO22 3 , PO22 4 , SO22 4 , HS2 and OH2), biothiols (GSH, Cys, Hcy, Me ¿Cys and lipoic acid), reducing agents (SO22 3 and S2O22 3 ) and oxidants (H2O2) demonstrated that only HS2 is able to induce the appearance of intense emission bands in the 400¿ 520 nm range in the four probes. The selectivity observed was ascribed to a unique hydrogen sulfide-induced hydrolysis of the 2,4-dinitrophenyl ether moiety that yielded the corresponding free highly fluorescent alcohols. The potential detection of intracellular HS2 was also studied.Financial support from the Spanish Government (Project MAT2012-38429-C04-01) and the Generalitat Valencia (Project PROMETEO/2009/016) is gratefully acknowledged. S.E. is grateful to the Generalitat Valenciana for his Santiago Grisolia fellow. L.E.S.F. also thanks the Carolina Foundation and UPNFM-Honduras for his doctoral grant.El Sayed Shehata Nasr, S.; De La Torre, C.; Santos Figueroa, LE.; Martínez-Máñez, R.; Sancenón Galarza, F.; Orzáez, M.; Costero, AM.... (2015). 2,4-dinitrophenyl ether-containing chemodosimeters for the selective and sensitive 'in vitro' and 'in vivo' detection of hydrogen sulfide. Supramolecular Chemistry. 27(4):244-254. https://doi.org/10.1080/10610278.2014.977286S24425427

Effectiveness of bailouts in the EU

Governments in the EU frequently bail out firms in distress by granting state aid. I use data from 86 cases during the years 1995-2003 to examine two issues: the effectiveness of bailouts in preventing bankruptcy and the determinants of bailout policy. The results are threefold. First, the estimated discrete-time hazard rate increases during the first four years after the subsidy and drops after that, suggesting that some bailouts only delayed exit instead of preventing it. The number of failing bailouts could be reduced if European control was tougher. Second, governments’ bailout decisions favored state-owned firms, even though state-owned firms did not outperform private ones in the survival chances. Third, subsidy choice is an endogenous variable in the analysis of the hazard rate. Treating it as exogenous underestimates its impact on the bankruptcy probability. Several policy implications of the results are discussed in the paper

Effects of hydrogen sulfide on hemodynamics, inflammatory response and oxidative stress during resuscitated hemorrhagic shock in rats

Introduction Hydrogen sulfide (H2S) has been shown to improve survival in rodent models of lethal hemorrhage. Conversely, other authors have reported that inhibition of endogenous H2S production improves hemodynamics and reduces organ injury after hemorrhagic shock. Since all of these data originate from unresuscitated models and/or the use of a pre-treatment design, we therefore tested the hypothesis that the H2S donor, sodium hydrosulfide (NaHS), may improve hemodynamics in resuscitated hemorrhagic shock and attenuate oxidative and nitrosative stresses. Methods Thirty-two rats were mechanically ventilated and instrumented to measure mean arterial pressure (MAP) and carotid blood flow (CBF). Animals were bled during 60 minutes in order to maintain MAP at 40 ± 2 mm Hg. Ten minutes prior to retransfusion of shed blood, rats randomly received either an intravenous bolus of NaHS (0.2 mg/kg) or vehicle (0.9% NaCl). At the end of the experiment (T = 300 minutes), blood, aorta and heart were harvested for Western blot (inductible Nitric Oxyde Synthase (iNOS), Nuclear factor-κB (NF-κB), phosphorylated Inhibitor κB (P-IκB), Inter-Cellular Adhesion Molecule (I-CAM), Heme oxygenase 1(HO-1), Heme oxygenase 2(HO-2), as well as nuclear respiratory factor 2 (Nrf2)). Nitric oxide (NO) and superoxide anion (O2 -) were also measured by electron paramagnetic resonance. Results At the end of the experiment, control rats exhibited a decrease in MAP which was attenuated by NaHS (65 ± 32 versus 101 ± 17 mmHg, P < 0.05). CBF was better maintained in NaHS-treated rats (1.9 ± 1.6 versus 4.4 ± 1.9 ml/minute P < 0.05). NaHS significantly limited shock-induced metabolic acidosis. NaHS also prevented iNOS expression and NO production in the heart and aorta while significantly reducing NF-kB, P-IκB and I-CAM in the aorta. Compared to the control group, NaHS significantly increased Nrf2, HO-1 and HO-2 and limited O2 - release in both aorta and heart (P < 0.05). Conclusions NaHS is protective against the effects of ischemia reperfusion induced by controlled hemorrhage in rats. NaHS also improves hemodynamics in the early resuscitation phase after hemorrhagic shock, most likely as a result of attenuated oxidative stress. The use of NaHS hence appears promising in limiting the consequences of ischemia reperfusion (IR)

Expression of Cystathionine β-synthase and Cystathionine γ-lyase in Human Pregnant Myometrium and Their Roles in the Control of Uterine Contractility

BACKGROUND: Human uterus undergoes distinct molecular and functional changes during pregnancy and parturition. Hydrogen sulfide (H(2)S) has recently been shown to play a key role in the control of smooth muscle tension. The role of endogenous H(2)S produced locally in the control of uterine contractility during labour is unknown. METHODOLOGY/PRINCIPAL FINDINGS: Human myometrium biopsies were obtained from pregnant women undergoing cesarean section at term. Immunohistochemistry analysis showed that cystathionine-γ-lyase (CSE) and cystathionine-β-synthetase (CBS), the principle enzymes responsible for H(2)S generation, were mainly localized to smooth muscle cells of human pregnant myometrium. The mRNA and protein expression of CBS as well as H(2)S production rate were down-regulated in labouring tissues compared to nonlabouring tissues. Cumulative administration of L-cysteine (10(-7)-10(-2) mol/L), a precursor of H(2)S, caused a dose-dependent decrease in the amplitude of spontaneous contractions in nonlabouring and labouring myometrium strips. L-cysteine at high concentration (10(-3) mol/L) increased the frequency of spontaneous contractions and induced tonic contraction. These effects of L-cysteine were blocked by the inhibitors of CBS and CSE. Pre-treatment of myometrium strips with glibenclamide, an inhibitor of ATP-sensitive potassium (K(ATP)) channels, abolished the inhibitory effect of L-cysteine on spontaneous contraction amplitude. The effects of L-cysteine on the amplitude of spontaneous contractions and baseline muscle tone were less potent in labouring tissues than that in nonlabouring strips. CONCLUSION/SIGNIFICANCE: H(2)S generated by CSE and CBS locally exerts dual effects on the contractility of pregnant myometrium. Expression of H(2)S synthetic enzymes is down-regulated during labour, suggesting that H(2)S is one of the factors involved in the transition of pregnant uterus from quiescence to contractile state after onset of parturition