Pharmacokinetics of sodium thiosulfate in Guinea pig perilymph following middle ear application

Hypothesis： To determine the pharmacokinetics of sodium thiosulfate in the inner ear perilymph following middle ear application in Guinea pigs. Background： Cisplatin chemotherapy is often associated with a dose-dependent high frequency senso- rineural hearing loss. Sodium thiosulfate has been shown to reduce cisplatin-induced ototoxicity when given intravenously, but this may limit the tumoricidal effects of the chemotherapy. Recent animal studies looking at middle ear application of sodium thiosulfate have shown prevention of outer hair cell and hearing loss, but the perilymph pharmacokinetics have not yet been established. Methods： Twenty Guinea pig ears were split into two groups and administered sodium thiosulfate to the middle ear at either a concentration of 250 mg/mL or 50 mg/mL for 30 min. Perilymph samples were then obtained serially through the round window over 6 h. Sodium thiosulfate concentrations were obtained using high-pressure liquid chromatography. Results： The 250 mg/mL group had a maximum perilymph concentration of 7.27 mg/mL （±0.83） that decreased to 0.94 mg/mL （±0.03） over 6 h. The 50 mg/mL group had an initial concentration of 1.63 mg/mL （±0.17） and was undetectable after 1 h. The half-life of sodium thiosulfate within perilymph was 0.74 h. Conclusions： and Relevance： The results of this study show that sodium thiosulfate is capable of diffusing through round window and into the inner ear perilymph. Peak levels decline over several hours after exposure. This has a potential application as a localized therapy in the prevention of cisplatin induced ototoxicity.

Novel Reduction of Sodium Alkyl Thiosulfates to Disulfides with TiCl_4/Sm System

Sodium alkyl thiosulfates(Bunte salts) can be readily reduced to the corresponding disulfides with TiCl4/Sm system in good to excellent yields under mild conditions

Novel Reduction of Arylsulfonyl Chlorides and Sodium Alkyl Thiosulfates to Disulfides with TiCl_4/Zn System

T1Cl4/Zn system reduces arylsulfonyl chlorides and sedium aldyl thiosulfates to corresponding disulfides in moderate to good yields

Oxidation inhibition of sulfite in dual alkali flue gas desulfurization system

A laboratory-scale well-mixed thermostatic reactor with continuously blasting air was used to investigate the oxidation inhibition of sulfite in dual alkali flue gas desulfurization （FGD） system. The effects of operating parameters such as pH value and catalyst concentration on the oxidation were studied. Sodium thiosulfate was used in the system, and was found that it significantly inhabited the sulfite oxidation. In the absence of catalyst, sodium thiosulfate at 12.67 mmol/L had an inhibition efficiency of approximately 98%. While in the presence of catalyst, sodium thiosulfate at 26.72 mmol/L had an inhibition efficiency less than 85.0%. The oxidation reaction order of sulfite in the sodium thiosulfate was determined to be -1.90 and 4）.55 in the absence and presence of the catalyst, respectively. Apparent activation energy of oxidation inhibition was calculated to be 53.9 kJ/mol. Pilot tests showed that the consumption rate of thiosulfate agreed well with the laboratory-scale experimental results.

Effect of α-Ketoglutarate on Cyanide-induced Biochemical Alterations in Rat Brain and Liver

Objective To investigate the biochemical changes in rat brain and liver following acute exposure to a lethal dose of cyanide, and its response to treatment of α-ketoglutarate （α-KG） in the absence or presence of sodium thiosulfate （STS）. Methods Female rats were administered 2.0 LD50 potassium cyanide （KCN; oral） in the absence or presence of pre-treatment （-10 rain）, simultaneous treatment （0 rain） or post-treatment （＋2-3 min） of α-KG （2.0 g/kg, oral） and/or STS （1.0 g/kg, intraperitoneal, -15 min, 0 rain or ＋ 2-3 min）. At the time of onset of signs and symptoms of KCN toxicity （2-4 min） and at the time of death （5-15 min）, various parameters particularly akin to oxidative stress viz. cytochrome oxidase （CYTOX）, superoxide dismutase （SOD）, glutathione peroxidase （GPx）, reduced glutathione （GSH） and oxidized glutathione （GSSG） in brain, and CYTOX, sorbitol dehydrogenase （SDH）, alkaline phosphatase （ALP）, GSH and GSSG in liver homogenate were measured. Results At both time intervals brain CYTOX, SOD, GPx, and GSH significantly reduced （percent inhibition compared to control） to 24%, 56%, 77%, and 65%, and 44%, 46%, 78%, and 57%, respectively. At the corresponding time points liver CYTOX and GSH reduced to 74% and 63%, and 44% and 68%, respectively. The levels of GSSG in the brain and liver, and hepatic ALP and SDH were unchanged, Pre-treatment and simultaneous treatment of α-KG alone or with STS conferred significant protection on above variables. Post-treatment was effective in restoring the changes in liver but failed to normalize the changes in the brain. Conclusions Oral treatment with α-KG alone or in combination with STS has protective effects on cyanide-induced biochemical alterations in rat brain and liver.

Basic requirements of dunk tank settings and verification of the disinfection effect in high-level biosafety laboratories

This study presents the structure and application of dunk tanks in high-level biosafety laboratories.The test methods and sterilization effects of dunk tanks were evaluated by using Bacillus subtilis as indicator.Results showed that sterilization effects of dunk tanks could be achieved by immersing the goods in 0.5%sodium hypochlorite disinfectant solution for 30 min at room temperature.Neutralizer sodium thiosulfate had no effect on the growth of Bacillus subtilis,and thus would not affect the disinfection results of sodium hypochlorite.Furthermore,suggestions for safe operation of dunk tanks are also provided in this study.