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Hydrogen sulfide is a toxic gas but also recognized as an endogenously produced metabolite in humans playing key roles. We previously identified trimethylsulfonium, which can be a methylation product of hydrogen sulfide but the stability in the production of trimethylsulfonium has not been investigated. In the present work, the intra- and inter-individual variability in the excretion of trimethylsulfonium over 2 months in a group of healthy volunteers was investigated. Urinary levels of trimethylsulfonium (mean: 56 nM, 95% CI: 48-68 nM) were > 100-fold lower than the conventional hydrogen sulfide biomarker thiosulfate (13 µM, 12-15 µM) and the precursor for endogenous hydrogen sulfide production cystine (47 µM, 44-50 µM). There was no correlation between urinary trimethylsulfonium and thiosulfate. Higher intra-individual variability in the excretion of trimethylsulfonium (generally 2-8 fold) than that for cystine (generally 2-3 fold) was found. Trimethylsulfonium displayed significant inter-individual variability with two concentration clusters at 117 nM (97-141) and 27 nM (22-34). In conclusion, the observed inter- and intra-individual variability must be considered when using urinary trimethylsulfonium as a biomarker., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Hydrogen sulphide (H 2 S) is one of the most toxic natural gas and represents a not rare cause of fatal events in workplaces. We report here a serious accidental poisoning by hydrogen sulphide inhalation involving six sailors. Three of them died while the other three survived and were transported to the emergency room. No greenish discolouration of the body, that could be a feature of these type of deaths, was observed at autopsy. Given that blood and/or urine H 2 S detection does not allow to discriminate if it is related to inhalation or to putrefactive processes, the determination of thiosulphate, H 2 S main metabolite, is decisive. The succession of fatal events reported here can be rebuilt by toxicological data interpretation: the subject 1 died after a longer interval of time as demonstrated by the highest blood and urine thiosulfate concentrations; the subject 2 died after a short interval of time as showed by a lower blood and urine thiosulfate concentrations than subject 1; the subject 3 died almost immediately after H 2 S inhalation since he showed the lowest blood thiosulfate concentration, and no trace of sulphide and thiosulfate was found in the urine., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Aims: Thiosulfate and sulfate are metabolites of hydrogen sulfide (H 2 S), a gaseous signaling molecule with cardiovascular (CV) protective properties. Urinary thiosulfate excretion and sulfate excretion are associated with favorable disease outcome in high-risk patient groups. We investigated the relationship between urinary excretion of sulfur metabolites, and risk of CV events and all-cause mortality in the general population. Results: Subjects ( n  = 6839) of the Prevention of Renal and Vascular End-stage Disease (PREVEND) study were followed prospectively. At baseline, 24-h urinary excretion of thiosulfate and sulfate was determined. Median urinary thiosulfate and sulfate excretion values were 1.27 (interquartile range [IQR] 0.89-2.37) μmol/24 h and 15.7 (IQR 12.0-20.3) mmol/24 h, respectively. Neither thiosulfate nor sulfate excretion showed an independent association with risk of CV events. Sulfate, but not thiosulfate, was inversely associated with risk of all-cause mortality, independent of potential confounders (hazard ratio 0.73 [95% confidence interval 0.63-0.84], p  < 0.001). This association appeared most pronounced for normolipidemic subjects ( p interaction  = 0.019). Innovation: The strong association between sulfate excretion and mortality in the general population emphasizes the (patho)physiological importance of sulfate or its precursor H 2 S. Conclusion: We hypothesize that urinary sulfate excretion, which is inversely associated with all-cause mortality in the general population, holds clinical relevance as a beneficial modulator in health and disease. Antioxid. Redox Signal. 30, 1999-2010.

Being a stable metabolite of hydrogen sulfide, thiosulfate has been utilized as an index for hydrogen sulfide poisoning (HSP). Thiosulfate analysis is mainly performed using gas chromatography/mass spectrometry (GC-MS) due to its high sensitivity and specificity. The GC-MS analysis requires two-step derivatizations of thiosulfate, and the derivative is not stable in solution as it has a disulfide moiety. To resolve this stability issue, we developed a novel analytical method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for monitoring the pentafluorobenzyl derivative of thiosulfate (the first reaction product of the GC-MS method) in this study. The established method exhibited high reproducibility despite being a more simplified and rapid procedure compare to the GC-MS method. Phenyl 4-hydroxybenzoate was used as an internal standard because 1,3,5-tribromobenzene which had been used in the GC-MS method was not suitable compound for LC-MS/MS with Electrospray ionization (ESI) negative detection. The linear regression of the peak area ratios versus concentrations was fitted over the concentration ranges of 0.5-250μM and 0.25-250μM in blood and urine, respectively. The validation results satisfied the acceptance criteria for intra- and inter-day accuracy and precision. Blood and urine samples from 12 suspected HSP cases were tested using this method. The thiosulfate concentration detected in the sample coincided well with that determined at the scene of each HSP accident., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

A new method for determination of thiosulfate in human urine has been developed and validated. Analytical procedure is very simple and consists of only few steps: derivatization of thiosulfate with 2-chloro-1-methylquinolinium tetrafluoroborate, centrifugation of a mixture, separation of so-formed derivative by micellar electrokinetic chromatography with sweeping and UV detection at 375 nm. A fused-silica capillary with an inlet to detector length of 51.5 cm and a total length of 60 cm (75 μm id) was served as a separation column. The separation voltage of 20.5 kV (∼160 mA) and buffer solution consisting of 0.055 mol/L sodium phosphate (pH 8), 25% acetonitrile, and 0.035 mol/L sodium dodecyl sulfate were found to be the most suitable conditions for the effective separation. The limit of quantification for thiosulfate was 4 μmol/L urine. The method was validated and calibrated for thiosulfate in the range of 4-64 μmol/L (R(2) = 0.9997). The relative standard deviation of the points of the calibration curve varied from 1.2 to 4.8% RSD., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Background: In 2013, thiosulfate in urine has been proposed as promising prostate cancer (PCa) biomarker. However, a missing comparison with other proven PCa markers suggested a re-evaluation study. Therefore, together with the authors from the initial study, the diagnostic accuracy of thiosulfate was compared with that of urinary prostate cancer associated 3 (PCA3), serum prostate health index (Phi), and percent free prostate-specific antigen (%fPSA). Thiosulfate was further measured in a multicenter approach to exclude center-related biases., Methods: Thiosulfate, calculated as ratio of thiosulfate to urinary creatinine (TS/Crea ratio), was measured in two cohorts in a total of 269 patients. In the retrospective study (n=160) PCA3, Phi, PSA, and %fPSA were compared with the TS/Crea ratio between patients with and without PCa according to the prostate needle biopsy results. The second prospective cohort included 109 patients from four centers., Results: The median TS/Crea ratio was not statistically different between the patients with and without PCa. The receiver-operating characteristics showed that the TS/Crea ratio was unable to discriminate between patients with and without PCa in contrast to %fPSA, Phi, and PCA3. In all four centers, the low median TS/Crea ratios (<1 mmol/mol) in both patient cohorts were confirmed and thiosulfate was again not able to distinguish between them (p-values, 0.13-0.90)., Conclusions: This study could not confirm the previously observed high median TS/Crea ratio in PCa patients in comparison to non-PCa patients. Thiosulfate subsequently failed as PCa biomarker while PCA3 and Phi showed the expected diagnostic improvement.

The UK Health and Safety Executive has investigated several incidents of workplace accidents involving hydrogen sulphide exposure in recent years. Biological monitoring has been used in some incidents to determine the cause of unconsciousness resulting from these incidents and as a supporting evidence in regulatory enforcement. This paper reports on three case incidents and discusses the use of biological monitoring in such cases. Biological monitoring has a role in identifying hydrogen sulphide exposure in incidents, whether these are occupational or in the wider environment. Sample type, time of collection and sample storage are important factors in the applicability of this technique. For non-fatal incidents, multiple urine samples are recommended at two or more time points between the incident and 15 h post-exposure. For routine occupational monitoring, post-shift samples should be adequate. Due to endogenous levels of urinary thiosulphate, it is likely that exposures in excess of 12 ppm for 30 min (or 360 ppm/min equivalent) would be detectable using biological monitoring. This is within the Acute Exposure Guideline Level 2 (the level of the chemical in air at or above which there may be irreversible or other serious long-lasting effects or impaired ability to escape) for hydrogen sulphide., (Crown Copyright © 2014. Published by Elsevier Ireland Ltd. All rights reserved.)

Background: Urinary sulfate (SO4(2-)) and thiosulfate (S2O3(2-)) can potentially bind with calcium and decrease kidney stone risk. We modeled the effects of these species on the concentration of ionized calcium (iCa) and on supersaturation (SS) of calcium oxalate (CaOx) and calcium phosphate (CaP), and measured their in vitro effects on iCa and the upper limit of stability (ULM) of these salts., Methods: Urine data from 4 different types of stone patients were obtained from the Mayo Nephrology Clinic (Model 1). A second data set was obtained from healthy controls and hypercalciuric stone formers in the literature who had been treated with sodium thiosulfate (STS) (Model 2). The Joint Expert Speciation System (JESS) was used to calculate iCa and SS. In Model 1, these parameters were calculated as a function of sulfate and thiosulfate concentrations. In Model 2, data from pre- and post STS urines were analyzed. ULM and iCa were determined in human urine as a function of sulfate and thiosulfate concentrations., Results: Calculated iCa and SS values for all calcium salts decreased with increasing sulfate concentration. Thiosulfate had no effect on these parameters. In Model 2, calculated iCa and CaOx SS increased after STS treatment, but CaP SS decreased, perhaps due to a decrease in pH after STS treatment. In confirmatory in vitro experiments supplemental sulfate, but not thiosulfate, significantly increased the calcium needed to achieve the ULM of CaP and tended to increase the oxalate needed to reach the ULM of CaOx. Sulfate also significantly decreased iCa in human urine, while thiosulfate had no effect., Conclusion: Increasing urinary sulfate could theoretically reduce CaOx and CaP stone risk. Although STS may reduce CaP stone risk by decreasing urinary pH, it might also paradoxically increase iCa and CaOx SS. As such, STS may not be a viable treatment option for stone disease.

In post-transplant conditions, sulfur may be protective by intermediate conversion to hydrogen sulfide and thiosulfate. However, sulfate, the end product of sulfur-containing amino acids (SAAs), contributes to metabolic acid load and may adversely influence acid-base homeostasis. We investigated the association of urinary sulfur metabolites with cardiometabolic parameters in renal transplant recipients (RTRs) and analyzed their predictive capacity for mortality. We studied urinary sulfate and thiosulfate excretion in 24-hour urine samples from 707 RTRs at a median 5.4 years (interquartile range, 1.9 to 12.2) after transplantation as well as from 110 controls. Diet was assessed for SAA content and various risk factors were measured. Urinary sulfate was similar, whereas thiosulfate was higher in RTRs versus controls. SAA intake was lower in RTRs compared with controls and correlated with sulfate but not thiosulfate excretion. Sulfate beneficially associated with eGFR, net acid excretion, systolic BP, high-sensitivity C-reactive protein, N-terminal probrain natriuretic peptide, and proteinuria (all P≤0.01). Thiosulfate beneficially associated with eGFR, serum acidity, high-sensitivity C-reactive protein, and N-terminal probrain natriuretic peptide (all P≤0.001). During a median 27 months (interquartile range, 22-36) of follow-up, 47 RTRs died. After adjustment for age, sex, and eGFR, hazard ratios for mortality were 0.87 (95% confidence interval, 0.82 to 0.92; P<0.001) for urinary sulfate and 0.60 (95% confidence interval, 0.41 to 0.59; P=0.01) for thiosulfate. Thus, despite the association of urinary sulfate with metabolic acid load, urinary sulfate and thiosulfate beneficially associated with survival in RTRs, possibly by influencing cardiovascular parameters. Intervention studies with exogenous sulfur are warranted to elucidate mechanisms underlying these promising associations in RTRs., (Copyright © 2014 by the American Society of Nephrology.)

The Occupational Medicine Forum is prepared by the ACOEM Occupational and Environmental Medical Practice Committee and does not necessarily represent an official ACOEM position. The Forum is intended for health professionals and is not intended to provide medical or legal advice, including illness prevention, diagnosis or treatment, or regulatory compliance. Such advice should be obtained directly from a physician and/or attorney.

Background: The aim of this study was to examine the level of thiosulfate in the urine of prostate cancer (PCa) patients and evaluate its usefulness in the diagnosis and monitoring of prostate malignant transformation. Thiosulfate is a naturally occurring product of hydrogen sulfide (H2S) metabolism. H2S is involved in many physiological and pathological processes including inflammation and tumorigenesis., Methods: The determination of thiosulfate in the urine of PCa patients and healthy controls was performed by reverse-phased liquid chromatography using 2-chloro-1-methylquinolinium tetrafluoroborate as a derivatization reagent. Thiosulfate concentrations were normalized to urinary creatinine levels to compensate for variable diuresis., Results: In the urine samples of PCa patients, the mean thiosulfate level was almost 50 times higher than in the control groups and five times higher than in the benign prostatic hyperplasia group. The level of thiosulfate did not correlate with the serum prostate-specific antigen (PSA) level or PSA density. Neither tumor stage nor tumor grade was associated with thiosulfate level., Conclusions: The results suggest that thiosulfate concentration in urine may be a good facilitator in the diagnostics of PCa. The predictive accuracy of this method is particularly valuable for the diagnosis of patients with low serum PSA level and negative digital rectal examination and transrectal ultrasound results.

Lime sulfide poisoning by the oral route is rarely encountered in the practice of forensic science, whereas hydrogen sulfide poisoning is seen frequently. We report here two cases of fatal lime sulfide poisoning with several related cases and in addition induced histological damage with acute inflammation in animal models under at similar concentrations. We also evaluated sulfide and thiosulfate concentrations and speculated as to the cause of pancreatic damage in these cases., (Copyright © 2012 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.)

To determine if ruminal hydrogen sulfide, urine thiosulfate, or blood sulfhemoglobin could be used as diagnostic indicators for sulfur-induced polioencephalomalacia, 16 steers (8 cannulated, 368 ± 12 kg; 8 unmodified, 388 ± 10 kg; mean ± standard error) were fed 1 of 2 dietary treatments. Diets consisted of a low sulfate (0.24% S; control) wheat midd-based pellet or the control pellet with sodium sulfate added to achieve a high-sulfate (0.68% S) pellet. As designed, intake did not differ (P = 0.80) between treatments. At 8 hr postfeeding, ruminal hydrogen sulfide was not affected by cannulation (P = 0.35) but was greater (P < 0.01) in high S (6,005 ± 475 mg/l) than control (1,639 ± 472 mg/l) steers. Time of day of sampling affected (P = 0.01) ruminal hydrogen sulfide, with peak concentrations occurring 4-12 hr after feeding. Urine was collected prefeeding (AM) and 7-9 hr postfeeding (PM). Urine thiosulfate concentrations of high S steers sampled in the PM were greater (P > 0.01) than in the AM. However, there was no difference due to time of sampling for control. In both the AM and PM, urine thiosulfate concentrations of high S were greater (P > 0.01) than control. Although hydrogen sulfide and thiosulfate were elevated by increased dietary S intake, a concentration at which polioencephalomalacia is likely to occur could not be determined. Sampling urine for thiosulfate or rumen gas for hydrogen sulfide of nonsymptomatic pen mates 4-8 hr after feeding may be useful to assess sulfur exposure and differentiate between causes of polioencephalomalacia.

Background and Objectives: Vascular calcification is a major cause of morbidity and mortality in dialysis patients. Human and animal studies indicate that sodium thiosulfate (STS) may prevent the progression of vascular calcifications. The pharmacokinetics of STS in hemodialysis patients has not been investigated yet., Design, Setting, Participants, & Measurements: STS was given intravenously to 10 hemodialysis patients on- and off-hemodialysis. Additionally, STS was applied to 9 healthy volunteers once intravenously and once orally. Thiosulfate concentrations were measured by using a specific and sensitive HPLC method., Results: In volunteers and patients, mean endogenous thiosulfate baseline concentrations were 5.5 ± 1.82 versus 7.1 ± 2.7 μmol/L. Renal clearance was high in volunteers (1.86 ± 0.45 ml/min per kg) and reflected GFR. Nonrenal clearance was slightly, but not significantly, higher in volunteers (2.25 ± 0.32 ml/min per kg) than in anuric patients (2.04 ± 0.72 ml/min per kg). Hemodialysis clearance of STS was 2.62 ± 1.01 ml/min per kg. On the basis of the nonrenal clearance and the thiosulfate steady-state serum concentrations, a mean endogenous thiosulfate generation rate of 14.6 nmol/min per kg was calculated in patients. After oral application, only 4% of STS was recovered in urine of volunteers, reflecting a low bioavailability of 7.6% (0.8% to 26%)., Conclusions: Given the low and variable bioavailability of oral STS, only intravenous STS should be prescribed today. The biologic relevance of the high hemodialysis clearance for the optimal time point of STS dosing awaits clarification of the mechanisms of action of STS.

In late 2007 and early 2008 two gentlemen were found dead in, or near to, enclosed hot pools fed with Rotorua's geothermal waters. Amidst much publicity the Coroner has ruled that the deaths were related to hydrogen sulphide poisoning. Following post mortem examinations, blood and urine samples were frozen and sent to the Toxicology Unit of ESR. These were then stored frozen until analysis. Hydrogen sulphide (H(2)S) is a potentially deadly gas at elevated levels, but is rapidly eliminated from the body and is unstable post mortem. Thiosulphate is a marker for the exposure to H(2)S, and as it is stable post mortem the samples were analysed to determine the thiosulphate levels present. The urine thiosulphate levels detected were above those seen in the urine samples measured from the only previous study of people exposed to the Rotorua thermal area and the blood levels were similar to literature values from fatalities exposed in workplaces such as sewage treatment plants., (Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.)

Ethylmalonic encephalopathy (EE, OMIM # 602473) is an autosomal recessive metabolic disorder of infancy affecting the brain, the gastrointestinal tract and peripheral vessels. It is caused by a defect in the ETHE1 gene product, which was recently shown to be part of a metabolic pathway devoted to sulphide detoxification. We report the application of improved biochemical and molecular approaches to the diagnosis of three cases of EE from two unrelated Cypriot families. The children presented all the typical biochemical hallmarks of the disease including elevated lactate and butyrylcarnitine in blood and elevated urinary excretion of ethylmalonic acid, 2-methylsuccinate, isobutyrylglycine and isovalerylglycine. We also detected an elevated level of thiosulphate in urine, which we propose as an additional biochemical marker of the disease. The proband of the first family was shown to be a compound heterozygote for a missense mutation in exon 5, L185R, and a deletion of exon 4. The deletion was identified using quantitative real-time polymerase chain reaction (qRT-PCR). Using the same technique, the proband of the second family was found to be homozygous for the exon 4 deletion. A prenatal diagnosis was performed for the second family using qRT-PCR, thus establishing the usefulness of RT-PCR in prenatal diagnosis., (© 2010 John Wiley & Sons A/S.)

The current work aimed at investigating the cognitive functions impairment among workers of sewer networks due to exposure to hydrogen sulfide (H(2)S) and the relation of this impairment, if any, to the level of H(2)S exposure biomarker 'urinary thiosulfate.' Besides, the validity of using Mini Mental State Examination (MMSE) as screening test for cognitive impairment among the exposed workers was tested. The work was conducted among 33 sewage network maintenance male workers and a matched unexposed control group (n = 30). The participants were subjected to clinical neurological history, estimation of urinary thiosulfate, and assessment of cognitive dysfunction by using neurophysiological (simple reaction time, P300 test) and neuropsychological tests (Wechsler Memory Scale) and frontal executive functions tests. Clinical neurological history revealed significantly higher neurological symptoms (headache, memory defects, lack of concentration) among exposed workers compared to their controls (p < 0.05). Exposed workers had significantly prolonged simple reaction time and delayed P300 latency and showed poor performance of most of neuropsychological tests. Marked elevation of urinary thiosulfate was observed among the exposed workers (p < 0.001) but this elevation was not correlated with the duration of exposure or any of the other measured parameters. Exposed workers had significantly lower mean value of MMSE scoring than that of the controls (p < 0.001). In conclusion, exposure to H( 2)S among sewer network workers is associated with cognitive impairment, which can be screened by applying MMSE as a simple rapid test for H( 2)S occupationally exposed workers.

Thiosulfate is a sulfate analogue with a thiosulfur substituent and is found in human samples. Its concentration in urine is increased in some diseases and after exposure to hydrogen sulfide gas. We have developed a sensitive, simple and cheap method for thiosulfate determination in urine. The method is based on precolumn derivatization with 2-chloro-1-methylquinolinium tetrafluoroborate followed by reversed-phase liquid chromatography separation and ultraviolet detection of 1-methyl-2-thioquinolone at 375 nm. The calibration curve for thiosulfate was linear in the tested range 0.5-50 micromol L(-1) with correlation coefficient better than 0.999. The analytical recovery and relative standard deviation values for precision within the calibration range were from 90.1% to 104.2% and from 2.39% to 5.59%, respectively. The lower limit of detection and quantitation were 0.3 and 0.5 micromol L(-1), respectively. The mean (range) concentration of thiosulfate normalized against creatinine for apparently healthy seven women and six men was 2.21 (1.45-2.77) and 2.51 (1.36-4.89)mmol mol(-1) creatinine, respectively. We monitored thiosulfate in urine samples from one volunteer for 24 h. The urinary excretion of thiosulfate was 21.4 micromol per 24 h. This method can be used for routine clinical monitoring thiosulfate in urine. Cysteine and cysteinylglycine can be measured concurrently, if needed.

An uncontrolled trial reported that sodium thiosulfate reduces formation of calcium kidney stones in humans, but this has not been established in a controlled human study or animal model. Using the genetic hypercalciuric rat, an animal model of calcium phosphate stone formation, we studied the effect of sodium thiosulfate on urine chemistries and stone formation. We fed genetic hypercalciuric rats normal food with or without sodium thiosulfate for 18 wk and measured urine chemistries, supersaturation, and the upper limit of metastability of urine. Eleven of 12 untreated rats formed stones compared with only three of 12 thiosulfate-treated rats (P < 0.002). Urine calcium and phosphorus were higher and urine citrate and volume were lower in the thiosulfate-treated rats, changes that would increase calcium phosphate supersaturation. Thiosulfate treatment lowered urine pH, which would lower calcium phosphate supersaturation. Overall, there were no statistically significant differences in calcium phosphate supersaturation or upper limit of metastability between thiosulfate-treated and control rats. In vitro, thiosulfate only minimally affected ionized calcium, suggesting a mechanism of action other than calcium chelation. In summary, sodium thiosulfate reduces calcium phosphate stone formation in the genetic hypercalciuric rat. Controlled trials testing the efficacy and safety of sodium thiosulfate for recurrent kidney stones in humans are needed.

An adult Japanese man (A) entered a pit to remove sludge in a drainage pipe at a dye works in Japan. When he took off a joint of the pipe, the sludge in the pipe flowed into the pit. As he suddenly lost consciousness, three colleagues (B, C, D) entered the pit to rescue him. All of these (A, B, C and D) lost consciousness in the pit, and died soon after the accident. Since hydrogen sulfide gas was detected in the sludge of the pit, gas poisoning was suspected. Toxicological analyses of sulfide and thiosulfate, a metabolite of sulfide, in blood and urine of the victims were made, using the extractive alkylation technique combined with gas chromatography/mass spectrometry. Sulfide and thiosulfate were detected in whole blood of the four workers at levels of 0.32-9.36 mg/l and 0.11-0.23 mmol/l, respectively. These concentrations were at least 6-187 times higher in sulfide and 37-77 times higher in thiosulfate than those in healthy persons, and were similar to values found in fatal cases of hydrogen sulfide poisoning. Thiosulfate was not detected in the urine of four workers, which indicated acute death. Based on these results, all four patients were victims of hydrogen sulfide poisoning, who died soon after the exposure.

Urinary calcium excretion increases by 1-2-fold during gestation in normal, uncomplicated pregnant women. Hypercalciuria occurs in all trimesters and elevates urine supersaturation with regards to calcium oxalate. However, crystalluria has not been a frequent clinical finding and stone formation is not a common complication of pregnancy. To elucidate this discrepancy we measured various chemical entities (i.e. calcium, oxalate, uric acid, phosphorous, magnesium, citrate, sulfate and thiosulfate) in urine at the end of each trimester of 25 pregnant women. Twenty-five healthy women served as controls. Our observations show that endogenous thiosulfate, a natural component of urine, increased considerably during pregnancy to approximately 36, 38 and 40 microM/24 hour at the end of each three trimesters. One month after delivery, endogenous thiosulfaturia and hypercalciuria, in parallel, returned to initial normal values. Consequently, it seems that gestational hyperthiosulfaturia protects hypercalciuric normal pregnant women from the risk of nephrolithiasis.

In two earlier publications we reported excellent therapeutic results in patients with recurrent calcium nephrolithiasis, using oral or intravenous i.v. sodium thiosulfate on the one hand, and on treatment of tumorus-soft periarticular tissues calcifications on the other. Thus, we considered useful to measure endogenous thiosulfaturia, using a specific HPLC method, in 25 healthy adult males and 25 patients with recurrent calcium nephrolithiasis. Healthy adult males excreted between 11 and 16 microM/24 hour of endogenous thiosulfate, while patients with recurrent calcium nephrolithiasis excreted significantly lower amounts of 6 and 10 microM/24 hour, except one patient, who did not excrete endogenous thiosulfate, reflecting probably a genetic abnormality. Thiosulfate is a unique agent for treatment of recurrent calcium nephrolithiasis as well as some other abnormal calcium depositions. Two doses of 5 mM sodium thiosulfate daily are therapeutically sufficient.

An adult man (A) entered a pit to collect seepage at an industrial waste site in Japan. As he suddenly lost consciousness, three colleagues (B, C, D) entered the pit to rescue him. All of these men lost consciousness in the pit. Two workers (A and B) died soon after the accident, one worker (C) died 22 days after the accident, and one worker (D) survived. Since hydrogen sulfide gas was detected in the atmosphere of the pit, gas poisoning was suspected. Toxicological analyses of sulfide and thiosulfate, a metabolite of sulfide, in blood and urine of the victims were made using the extractive alkylation technique combined with gas chromatography/mass spectrometry (GC/MS). Sulfide was detected in the blood of A and B at levels of 0.13 and 0.11 mg/L, respectively, somewhat higher than in healthy persons. Thiosulfate was detected in whole blood of deceased victims A and B, in the plasma of deceased victim C, at concentrations of 10.53, 4.59, and 4.14 mg/L, respectively. These values were similar to those found in fatal cases of hydrogen sulfide poisoning. Thiosulfate was not detected in the plasma of survivor D. With respect to urine samples, thiosulfate was the highest in the non-acute death victim C (137.20 mg/L), followed by that in the survivor D (29.34 mg/L), and low (0.90 mg/L) and not detected in the acute death victims, A and B, respectively. Based on these results, all four patients were victims of hydrogen sulfide poisoning. The concentrations of thiosulfate in blood and urine were more useful than that for sulfide for determining hydrogen sulfide poisoning. Thiosulfate in urine was the only indicator of hydrogen sulfide poisoning in the non-fatal victim.

Background: Hydrogen sulfide is a toxic gas about which much has been written. We discuss here several issues we believe would benefit from further clarification., Conclusions: We conclude that: 1) Certain neurotoxic effects of exposure are probably due to a direct toxic effect on the brain, while others are almost certainly a result of hypoxia secondary to H2S-induced respiratory insufficiency; 2) pulmonary edema is a common consequence of poisoning and there is suggestive evidence of hyperactive airway responses in some individuals following brief H2S-induced unconsciousness (knockdown); 3) criteria for acceptable community levels are very different than those governing occupational standards; 4) urinary thiosulfate determinations can be useful for monitoring occupational exposure; and 5) determination of sulfide ion concentrations in blood or major organs can be useful in corroborating a diagnosis of fatal H2S toxicity, but there are many pitfalls in collecting, storing, and analyzing tissue and fluid samples.

Thiosulfate is a naturally occurring product of sulfur metabolism. Assays of urinary thiosulfate have been based on the reaction with cyanide to form thiocyanate. However, matrix interferences and background variation in endogenous thiocyanate excretion place serious constraints on this method for determination of physiological amounts of thiosulfate in urine. We describe a column-switching ion chromatographic separation for urinary thiosulfate that allows for sensitive and accurate detection by ion conductimetry. In 20 adult volunteers, we found a lower urinary thiosulfate (8.50 +/- 7.39 mumol/24 h, mean +/- S.D.) than others have described, although the upward skew of the results (median, 6.90; range, 0.84-32 mumol/24 h) was similar. However, we have not observed any of the interferences and the sensitivity of our technique (< 0.2 mumol/24 h) allows for detection of thiosulfate in all control samples. This sort of methodological improvement will be essential for any study of physiological thiosulfate metabolism.

A simple and sensitive method to determine thiosulfate in human blood and urine was devised. Thiosulfate was first alkylated with pentafluorobenzyl bromide, with L-ascorbic acid as the stabilizer and sodium chloride as the catalyst. The alkylated thiosulfate was oxidized with iodine to obtain bis(pentafluorobenzyl)disulfide, which was then subjected to gas chromatography and gas chromatography/mass spectrometry. Mass fragmentography was used to identify the disulfide, and gas chromatography with an electron capture detector was used for quantitative determination. The lower limit of detection was 0.003 mumol/mL.

To establish the usefulness of the bovine clinical renal function tests, experimental glomerulonephritis was experimentally induced in calves and some renal clearance tests were performed. Two (No. 1, 2) of three calves were injected intravenously with anti-bovine kidney rabbit serum (antiserum) and the other (No. 3) with normal rabbit serum (control serum). The early stage of proliferative glomerulonephritis was observed in the kidneys of Nos. 1 and 2. The degree of lesions in No. 1 was severer than that in No. 2. No remarkable change was observed in the kidneys of No. 3. Endogenous creatinine clearance value (CCRE), thiosulfate clearance value (CTHIO) and maximal tubular secretion of para-amino hippuric acid (TmPAH) of all calves did not show remarkable changes after the injection of antiserum or control serum. In the phenolsulfonphthalein (PSP) test, PSP excretion of Nos. 1 and 2 was disposed to delay after the injection, and in No. 3 there was no significant change after the injection. PAH clearance value (CPAH) of No. 1 decreased from 10.24 to 6.96 ml/min/kg (-32%). A small change was noted in the CPAH of Nos. 2 and 3. These results suggest that the simplified method for measuring CPAH performed in this study could assess the lesions formed in No. 1, which was pathologically diagnosed as the early stage of proliferative glomerulonephritis.

A method using high-performance liquid chromatography with mercury-based electrochemical detection has been developed for the determination of thiosulphate in urine. The chromatographic separation is based upon ion-pair formation between thiosulphate and tetrabutylammonium and reversed-phase chromatography. The method was compared with an earlier reported colorimetric assay and found to be superior with respect to specificity and sensitivity.

A simple technique using reverse-phase ion-pair liquid chromatography for measurement of exogenous thiosulfate is described. Accurate measurement of thiosulfate in plasma and urine was permitted by precolumn derivatization with monobromobimane, a substance that readily yields fluorescent compounds upon reaction with a variety of biologically important nucleophiles including glutathione, cysteine, and sulfite. Using an injection volume of 50 microliters, as little as 0.16 nmol of thiosulfate was reliably measured. The interassay precision of the method was reflected by a coefficient of variation of 7.7% while the coefficient of variation for interassay analysis was 2.6%. Recovery of thiosulfate from plasma was 96.9 +/- 3.2% and greater than 98% from urine. The simplicity, sensitivity, and precision of the method make it ideal for the study of thiosulfate and other important nucleophiles in body fluids.

Anti-cyanide action by sodium thiosulfate (ST) was enhanced by prior administration of chlorpromazine (CPZ). However, CPZ (alone) provided no protection against cyanide lethality. To investigate the possibility that CPZ enhances thiocyanate formation in ST-pretreated mice, the effects of CPZ on rhodanese activity and the time course of plasma thiocyanate concentrations were investigated. CPZ did not alter hepatic rhodanese kinetics nor did it enhance plasma thiocyanate concentrations in ST-pretreated mice. The effect of CPZ and ST on the time course of cytochrome oxidase inhibition and recovery, in vivo, was also investigated. At 4 mg KCN/kg, maximal inhibition of brain (40%) and heart (60%) cytochrome oxidase occurred 10 to 20 min post-challenge in control and CPZ-pretreated mice, while no inhibition occurred in ST- and CPZ/ST-pretreated mice. Twenty milligrams KCN/kg caused 100% lethality in control and CPZ-pretreated mice and 6/25 and 4/20 deaths were observed in ST- and CPZ/ST-pretreated mice, respectively. No significant inhibition of brain, heart, and liver cytochrome oxidase activities was observed in surviving ST- and CPZ/ST-pretreated mice challenged with 20 mg KCN/kg. Control and CPZ-pretreated mice died within 5 min of KCN challenge and had almost the same degree of inhibition of brain (35 and 29%, respectively) and heart (60 and 55%, respectively) cytochrome oxidase as did similarly pretreated mice 5 min after challenge with a nonlethal cyanide dose (4 mg/kg). Our results suggest that CPZ does not enhance the formation of thiocyanate in ST-pretreated mice. In addition, the similar degree of cytochrome oxidase inhibition noted after both lethal and nonlethal KCN treatments raises questions as to the ultimate target in cyanide-induced lethality.

Urinary thiosulphate analysed as its bromobimane complex by liquid chromatography revealed quantitatively a preceding hydrogen sulphide gas exposure. The highest thiosulphate concentrations were detected 15 h after the exposure. Controls without a contact to sulphides showed low excretion rates of thiosulphate so that exposures clearly below the fatal hydrogen sulphide gas concentrations could be detected. The urinalysis can therefore be used in the occupational health care as well as for forensic ends.

Thirty-four idiopathic rapid calcium stone formers (24 male/10 female) were studied. Their ages ranged from 20 to 60 years (40 +/- 11) and all had good renal function. The trial comprised two consecutive periods of 3 years and 4 years duration respectively. In the first (control period), the patients were maintained on a customary diet with an adequate fluid intake sufficient to produce about 2 liters of urine daily. In the second (treatment period), they received a similar diet plus 20 mmol of sodium thiosulphate daily. New stone development fell from 100 in the control period to 15 in the treatment period, corresponding to a rate of 0.98 and 0.11 per year (p less than 0.001). It is suggested that the benefit from sodium thiosulphate results from calcium thiosulphate formation in urine, a salt with a molar solubility of 250 to 100.000-fold greater than that of other urinary calcium salts.

Thiosulfate concentrations and pharmacokinetics were studied in relation to sodium nitroprusside before, during, and after anesthesia. Normal thiosulfate concentrations were 1.13 +/- 0.11 mg/dl and 0.28 +/- 0.02 mg/dl in plasma and urine, respectively. Cholecystectomy patients had similar concentrations during surgery, with bile thiosulfate concentration of 13.72 +/- 2.95 mg/dl. Fasting patients and children had significantly higher plasma and urine thiosulfate concentrations. Over 99% of endogenous filtered thiosulfate was reabsorbed by the kidney in the average case. Coronary bypass patients had decreased plasma thiosulfate levels and increased excretion postoperatively. Disappearance of injected thiosulfate was biphasic; the distribution phase was dependent on the initial rate of injection, and the elimination phase depended on extracellular fluid turnover and renal excretion. Cholecystectomy patients on diuretics had a markedly increased rate of excretion, 56% within 100 min, versus normal subjects who excreted less than 50% in up to 18 h. In children, plasma thiosulfate did not change significantly, while blood cyanide concentration increased significantly during sodium nitroprusside administration and surgery. Thiosulfate did not change during recovery while cyanide decreased. Normal production of thiosulfate in humans may be limited; hence, continuous thiosulfate infusion may be required during sodium nitroprusside administration.

The urinary excretion of sulfur-containing compounds was studied in 11 burned patients during the first 10 days after injury. They were all given carbohydrate and fat by parenteral nutrition. Two patients also received large amounts of amino acids including methionine, whereas five patients were given amino acids including moderate amounts of methionine and cysteine. A sustained high excretion of mercaptolactate occurred in most patients. The excretion was not influenced by the type of parenteral nutrition, but related to the area of burned skin. A normal excretion of methionine, cyst(e)ine, inorganic sulfate, taurine, mercaptoacetate, thiosulfate, and thiocyanate was found at the end of the observation period in patients without amino acid therapy. Increased amounts of inorganic sulfate and methionine were excreted in patients receiving high doses of methionine, whereas an increased cyst(e)ine and taurine excretion was the most prominent finding in patients receiving moderate amounts of methionine and cysteine. These results indicate that burned patients have an unimpaired ability to metabolize sulfur amino acids. Patients not receiving amino acids or receiving moderate amounts of cysteine and methionine showed a negative sulfur balance, whereas patients given high doses of methionine maintained sulfur balance at near-zero levels. However, since signs of hepatic dysfunction appeared in the latter group, parenteral nutrition with amino acid mixtures containing high amounts of methionine is not recommended during the catabolic phase for burned patients.

A method is described for the determination of thiosulphate in urine. After removal of interfering compounds, including endogenous thiocyanate by ion exchange, thiosulphate is converted to thiocyanate in the presence of cyanide and cupric ions. The thiocyanate formed is concentrated by ion exchange, eluted with an acid solution of ferric ions and the ferric thiocyanate complex determined colorimetrically. Healthy human subjects excreted 31.7 +/- 12.8 mumol/24 h (mean +/- SD) thiosulphate.