Toxicology of Hydrogen Sulfide

Abstract

Significant progress has been made in determining the action of sulfide on the primary target organs. It is reasonably clear that sulfide causes both K(+)-channel-mediated hyperpolarization of neurons and potentiation of other inhibitory mechanisms. It is not clear whether these processes are similar to those that occur in anoxia. Changes in perinatal and adult brain neurotransmitter content and release may be related to clinical impairment of cognition. H2S exposures at concentrations below the current occupational limits cause physiological changes in pulmonary function, thus suggesting that asthmatics are at risk. Studies of fetal and neonatal brain tissue have shown an abnormal development, and the long-term consequences of these neuronal changes have not yet been assessed. Finally, new approaches to therapy are required, such as the use of agents that actively remove sulfide from its sites of action. This may prove more useful in preventing some of the long-term adverse sequelae than the use of nitrites and hyperbaric O2, although the latter should be used in cases of pulmonary edema.

Acute Inhalation Injury

“…It is a colorless, highly flammable and explosive gas. Being a respiratory irritant and asphyxiant, also known as "sewer or swamp gas" with its "rotten egg" odor that is detectable at concentrations as low as 0.5 ppm, it may not provide adequate warning of hazardous concentrations since the victim may suffer olfactory fatigue [28][29][30].…”

“…Pulmonary edema can occur at concentrations of 250 ppm. Systemic and neurologic effects develop at higher concentrations, with sudden loss of consciousness and even death due to asphyxia above 700 ppm and 1000 ppm, respectively [28][29][30].…”

Calculation of Conditional Equilibrium in Serial Multiple Precipitation of Metal Sulfides With Hydrogen Sulfide Stream Generated From Sodium Sulfide: A Didactic Tool for Chemistry Teaching

“…Practically it can be expressed as a sum of all (deprotonated and (5) and (6) we will obtain: (9) or (10) Further (11) and the conditional equilibrium concentration of sulfide anion is…”

“…Immediate death caused by total breath paralyzation comes by breathing air with hydrogen sulfide concentration of 1.5 mg dm -3 because hydrogen sulfide is bonded to Fe in enzymes necessary for breathing in cell mitochondria, blocking oxygen. [9][10][11] However, hydrogen sulfide is not just toxic, but has some positive effects on human health. It is present in blood or plasma serum, however biological concentrations of H 2 S are very low due to difficulties with its detection.…”

Possible chemical mechanisms underlying the antitumor activity of S-deoxyleinamycin

“…It seems likely that thiol-mediated generation of H 2 S contributes to the generation of reactive oxygen species and to the biological activities of polysulfides and persulfides. [52][53][54][55][56][57] The presence of H 2 S in our DNA-cleavage assays may contribute to the substantial increase in the yield of strand breaks observed upon addition of SOD (Table 1). Typically, SOD catalyzes the disproportionation of two molecules of O 2 • − to H 2 O 2 and O 2 .…”