Sodium Thiosulfate in Acute Myocardial Infarction: A Randomized Clinical Trial.

In this proof-of-principle trial, the hypothesis was investigated that sodium thiosulfate (STS), a potent antioxidant and hydrogen sulfide donor, reduces reperfusion injury. A total of 373 patients presenting with a first ST-segment elevation myocardial infarction received either 12.5 g STS intravenously or matching placebo at arrival at the hospital and 6 hours later. The primary outcome, infarct size, measured by cardiac magnetic resonance at 4 months after randomization, did not differ between the treatment arms. Secondary outcomes were comparable as well, suggesting no clinical benefit of STS in this population at relatively low risk for large infarction.

Superfast degradation of refractory organic contaminants by ozone activated with thiosulfate: Efficiency and mechanisms.

Thiosulfate (S2O32-) is frequently used as an ozone (O3) quenching agent when investigating the ozonation of organic contaminants and the kinetics thereof. In this study, however, O3 is activated by S2O32-, resulting in a superfast degradation of O3-refractory contaminants. Therefore, the focus of this study is the exploration into the enhancing role of S2O32- in the degradation of refractory organic contaminants by O3, which has been overlooked thus far. Results obtained from scavenging experiments and electron paramagnetic resonance (EPR) spectra verify that •OH generated from the reaction of S2O32- with O3 is mainly responsible for the superfast degradation of O3-refractory contaminants. The •OH yield from the O3/S2O32- process is determined to be 0.216. A plausible mechanism for the generation of •OH from the O3/S2O32- process is proposed with the implementation of density functional theory (DFT). Initially, ozone reacts with a sulfur of S2O32- to form OOOSSO32-. The adduct then rearranges to OO(O)SSO32- or HOO(O)SSO32- in the presence of H+, which cleaves to give a sulfoxide radical cation and O2•-/HO2•. O2•-/HO2• is rapidly transformed into •OH by O3 through a series of steps. Degradation efficiency of O3-refractory contaminants of this process highly depends on the molar ratio of S2O32- and O3 ([S2O32-]:[O3]). The optimal [S2O32-]:[O3] is pH dependent in synthetic water (e.g. 0.3 at pH 7). The presence of bicarbonate inhibits the degradation of refractory contaminants by the O3/S2O32- process. Humic acid exhibits a slight enhancing effect at low concentrations (0.1-0.2 mg-C/L), and an inhibiting effect at higher concentrations (≥0.4 mg-C/L). In addition, the efficacy of the O3/S2O32- process in real water matrices is also confirmed.

Toxic inhalational injury.

A middle-aged patient presented with toxic inhalational injury, and was resuscitated prehospitally and treated in the emergency department for smoke inhalation, carbon monoxide (CO) exposure and cyanide poisoning with the use of antidotes. Due to the CO effects on spectrophotometry, an anaemia initially identified on blood gas analysis was thought to be artefactual, but was later confirmed by laboratory testing to be accurate. In addition, cyanide can confound haemoglobin testing due to its use in the analytical process and non-cyanide analysis is required when there is suspected exposure. Although no consensus exists on a first-line cyanide antidote choice, hydroxocobalamin is the only antidote without a serious side effect profile and/or deleterious cardiovascular effects. We propose prehospital enhanced care teams consider carrying hydroxocobalamin for early administration in toxic inhalational injury.

Efficacy of intralesional sodium thiosulfate for the treatment of dystrophic calcinosis cutis: A double-blind, placebo-controlled pilot study.

BACKGROUND: Intralesional injection of sodium thiosulfate has emerged as a promising therapy for calcinosis cutis, but to our knowledge there are no randomized controlled trials evaluating its efficacy as a treatment. OBJECTIVE: Conduct a prospective, double-blinded investigation of intralesional sodium thiosulfate versus normal saline in the treatment of dystrophic calcinosis cutis. METHODS: This prospective pilot study injected normal saline or sodium thiosulfate at 0.1 mL/cm2 into lesions at baseline and at 1- and 2-month follow-up. Subjects were followed for a total of 12 weeks. An in-person Physician Global Assessment score was assigned by the injecting physician at each visit and was repeated by an independent observer. RESULTS: Of 4 subjects who completed the study, only 1 experienced improvement in the size and Physician Global Assessment score of the lesion. By 3-month follow-up, there was no difference between the average size of the treatment and control lesions (P = .39). LIMITATIONS: This was a small single-center study with limited demographic diversity and a short follow-up period. Only dystrophic calcinosis cutis subjects were included, and subjects received only 3 monthly injections of sodium thiosulfate. CONCLUSIONS: With only 1 positive response, our results highlight the need for further study of sodium thiosulfate treatment for dystrophic calcinosis.

Liberation of Hydrogen Sulfide from Dicysteinyl Polysulfanes in Model Wine.

Diorganopolysulfanes can be generated when hydrogen sulfide (H2S) and thiols are oxidized in the presence of Cu(II) under conditions usually aimed at removing H2S from wine. This work sought to understand if polysulfanes could act as latent sources of H2S during postbottling storage. The stability of the polysulfanes formed in situ in model wine containing cysteine, H2S, and transition metals was dependent both on the number of sulfur linking atoms (Sn) and on the presence of a reducing agent, such as sulfur dioxide or ascorbic acid. A polysulfane containing three linking sulfur atoms was the most stable, with 84% of the relative initial amount remaining in solution after six months, compared to polysulfanes containing four or more linking sulfur atoms that decomposed rapidly, with 26% remaining after six months. Importantly, sulfur dioxide was associated with the rapid degradation of polysulfanes and subsequent liberation of H2S. Three cysteine- S-sulfonates were also tentatively identified, which gives insight into the possible release mechanisms involved with H2S reappearance.

Na2S, a fast-releasing H2S donor, given as suppository lowers blood pressure in rats.

BACKGROUND: Hydrogen sulfide (H2S) is involved in blood pressure control. The available slow-releasing H2S-donors are poorly soluble in water and their ability to release H2S in biologically relevant amounts under physiological conditions is questionable. Therefore, new slow-releasing donors or new experimental approaches to fast-releasing H2S donors are needed. METHODS: Hemodynamics and ECG were recorded in male, anesthetized Wistar Kyoto rats (WKY) and in Spontaneously hypertensive rats (SHR) at baseline and after: 1) intravenous (iv) infusion of vehicle or Na2S; 2) administration of vehicle suppositories or Na2S suppositories. RESULTS: Intravenously administered vehicle and vehicle suppositories did not affect mean arterial blood pressure (MABP) and heart rate (HR). Na2S administered iv caused a significant, but transient (2-5min) decrease in MABP. Na2S suppositories produced a dose-dependent hypotensive response that lasted ∼45min in WKY and ∼75-80min in SHR. It was accompanied by a decrease in HR in WKY, and an increase in HR in SHR. Na2S suppositories did not produce a significant change in corrected QT, an indicator of cardiotoxicity. Na2S suppositories increased blood level of thiosulfates, products of H2S oxidation. CONCLUSIONS: Na2S administered in suppositories exerts a prolonged hypotensive effect in rats, with no apparent cardiotoxic effect. SHR and WKY differ in hemodynamic response to the H2S donor. Suppository formulation of fast-releasing H2S donors may be useful in research, if a reference slow-releasing H2S donor is not available.

Mechanistic Study of a Photocatalyzed C-S Bond Formation Involving Alkyl/Aryl Thiosulfate.

This study presents thioether construction involving alkyl/aryl thiosulfates and diazonium salt catalyzed by visible-light-excited [Ru(bpy)3 Cl2 ] at room temperature in 44-86 % yield. Electron paramagnetic resonance studies found that thiosulfate radical formation was promoted by K2 CO3 . Conversely, radicals generated from BnSH or BnSSBn (Bn=benzyl) were clearly suppressed, demonstrating the special property of thiosulfate in this system. Transient absorption spectra confirmed the electron-transfer process between [Ru(bpy)3 Cl2 ] and 4-MeO-phenyl diazonium salt, which occurred with a rate constant of 1.69×10(9) M(-1) s(-1) . The corresponding radical trapping product was confirmed by X-ray diffraction. The full reaction mechanism was determined together with emission quenching data. Furthermore, this system efficiently avoided the over-oxidation of sulfide caused by H2 O in the photoexcited system containing Ru(2+) . Both aryl and heteroaryl diazonium salts with various electronic properties were investigated for synthetic compatibility. Both alkyl- and aryl-substituted thiosulfates could be used as substrates. Notably, pharmaceutical derivatives afforded late-stage sulfuration smoothly under mild conditions.