Objective: To establish an ultrahigh performance liquid chromatography tandem mass spectrometry method for the determination of creatinine (Cre) and 2-thiothiazolidine-4-carboxylic acid (TTCA) in urine. Methods: In October 2020, the end-of-shift urine samples of the monitored subjects were taken, and the filtrate was prepared by centrifugation. After separated by ultra high performance liquid chromatography C18 column, acetonitrile and 0.2% acetic acid aqueous solution were used as mobile phases for gradient elution, the three quadrupole tandem mass spectrometry adopted an electrospray ion source (ESI) , the ion source temperature was 500 ℃ , and the air curtain gas flow rate was 31.4 L/min, qualitative and quantitative analysis of Cre and TTCA were carried out under the multiple reaction monitoring mode. Results: The linear range of Cre was 1.0-1 000.0 μg/L, the linear equation was y=947.3x-1605.6, and the correlation coefficient was 0.9994. The detection limit and the limit of quantitation were 0.3, 1.0 μg/L. When the addition concentrations were 50.0, 150.0 and 450.0 μg/L, the recovery rates were 92.8%-94.6% , the intra assay precisions were 3.6%-5.7% , and the inter assay precisions were 3.4%-5.4%. The linear range of TTCA was 0.1-200.0 μg/L, the linear equation was y=1164.7x-2243.9, and the correlation coefficient was 0.9991. The detection limit and the limit of quantitation were 0.03, 0.1 μg/L. When the addition concentrations were 10.0, 40.0 and 160.0 μg/L, the recovery rates were 90.8%-93.6%, the intra assay precisions were 4.6%-7.4%, and the inter assay precisions were 4.4%-6.9%. Conclusion: The sample pretreatment process of the ultra high performance liquid chromatography tandem mass spectrometry method for the determination of Cre and TTCA in urine is simple, and the continuous determination of Cre and TTCA in urine can be realized only by switching mass spectrometry parameters under the same chromatographic conditions, which is accurate and efficient, and each performance index of the method meets the determination requirements.
Chromatography, High Pressure Liquid ; Creatinine ; Humans ; Tandem Mass Spectrometry ; Thiazolidines

OBJECTIVETo synthesize epalrestat and to improve the method of synthesis.

METHODSGlycine reacted with carbondisulfide,then with ClCH(2)COONa to give 3-carboxymethylrhodanine. PhCHO reacted with CH(3)CH(2)CHO in NaOH/EtOH solution to produce 2-methylcinnamaldehyde.3-carboxymethylrhodanine and 2-methylcinnamaldehyde were treated with NH(3).H(2)O to obtain epalrestat.

RESULTThe described method was effective in synthesis of Epalrestat and the yield was higher than that of in references.

CONCLUSIONThe results suggest that this method is suitable for industrial production.

Aldehyde Reductase ; antagonists & inhibitors ; Enzyme Inhibitors ; chemical synthesis ; Rhodanine ; analogs & derivatives ; chemical synthesis ; Thiazolidines

OBJECTIVETo study the urinary excretion pattern for of 2-thio-thiazolidine-4-carboxylic acid (TTCA) in workers exposed to CS2, so as to provide experimental basis for working out biomonitoring measures for short-term exposure to CS2.

METHODSSixty-nine subjects were divided into three groups: (1) fourteen volunteers who had not been exposed to CS2 before were exposed to CS2 for 2 hours, their urine samples were collected and analyzed at different time points; (2) The urine samples of 15 occupational exposure workers were collected on pre-shift, mid-shift, post-shift; (3) The relationship between 8 h time weighted average CS2 exposure concentrations (PC-TWA) and TTCA levels of post-shift urine was studied among 40 workers chronically exposed to CS2.

RESULTS(1) In the 1st group, urine TTCA level reached the peak [(1.03 +/- 0.72) mg/gCr] 4 h after exposure; (2) In the 2nd group, urine TTCA level on pre-shift [(0.37 +/- 0.28) mg/gCr] was lower than that on mid-shift [(1.23 +/- 0.71) mg/gCr, P<0.01] and post-shift [(1.31 +/- 0.78) mg/gCr, P<0.01]; (3) In the 3rd group, there was a linear relationship between the post-shift urine TTCA level and 8 h CS2 exposure concentrations dose (PC-TWA). The regression equation is Y(TTCA mg/gCr)=1.163 6X(CS2 mg/m3)-5.411 6.

CONCLUSIONThe post-shift urine TTCA levels may be regarded as a bio-monitoring index for workers exposed to CS2.

Adult ; Carbon Disulfide ; metabolism ; Environmental Monitoring ; Humans ; Male ; Middle Aged ; Occupational Exposure ; Thiazoles ; urine ; Thiazolidines

OBJECTIVEEstablishment of determination method of 2-thiothiazolidine-4-carboxylic acid (TTCA) in urine with HPLC.

METHODSA volume of 0.5 ml hydrochloric acid (2 mol/L) and 0.5 ml pure water was added into 1 ml urine, and then extracted by 4 ml of diethyl ether by shaking for 2 min. Remove the water phase in a tube with plug and extract again, mix the two extraction diethyl ether together, take 4 ml by adding 2 ml borax-monopotassium phosphate buffer and shaking for 2 min to extract, then take the water phase to detect. A C(18) column and UV detector were used for separating and detecting. The wavelength was 273 nm, the flow rate was 1.0 ml/min, and the injection volume was 20 µl.

RESULTSTTCA has a good linearity (r = 0.9995) over the concentration of1 1 ∼ 10 µg and the minimum detectable concentration of TTCA in urine was 0.1 µg/ml. The within-day precision (RSD) were 8.4%, 3.0% and 1.7%, the between-day precision (RSD) were 11%, 3.8%, 1.9%, respectively. The extraction recovery were between 80% ∼ 102%.

CONCLUSIONThe method was accurate and sensitive to detect TTCA in urine.

Carbon Disulfide ; urine ; Chromatography, High Pressure Liquid ; methods ; Humans ; Thiazolidines ; urine

Objective: To establish a high performance liquid chromatography method for the determination of 2-thioxothiazolidine-4-carboxylic acid (TTCA) in urine. Methods: After acidification with hydrochloric acid, TTCA in urine was first extracted by ethyl acetate with excessive sodium chloride, then gradient separated by a symmetry C18 column and then detected by a diode array detector. The quantification was based on a working curve of external standard method. Results: The linear relationship of TTCA in urine was good in the range of 0.03-10.00 mg/L, and the correlation coefficient was 0.9999. The detection limit and minimum quantitative concentration of TTCA in urine were 0.008 mg/L and 0.027 mg/L. The intra-assay precision of the method was 0.9%-1.4%, the inter-assay precision was 1.3%-3.5%, and the average recovery was 85.0%-92.7% while the concentrations of TTCA in urine was 0.8, 2.0 and 8.0 mg/L, respectively (n=6) . Conclusion: The gradient elution high performance liquid chromatography method has simple operation and high sensitivity, and it is suitable for the determination of TTCA on a low level in urine for occupational workers exposure to carbon disulfide.
Carbon Disulfide ; Chromatography, High Pressure Liquid/methods* ; Humans ; Thiazoles/urine* ; Thiazolidines ; Thiones

AIMTo study the four diastereomers of leucogen and structure of the related substances.

METHODSLC-DAD, LC-MS/MS and LC- 1H NMR were used. LC was carried out with a Phenomnex Luna C18 (250 mm x 4.60 mm ID, 5 microm) column and a mobile phase of water-acetonitrile-glacial acetic acid (58:42: 0.3).

RESULTSThe structures of leucogen and its related substances were identified. Leucogen and the related substances were found to have four diastereomers in solution state separately. The stability and transformation of the four diastereomers were analyzed and 3R4S5R was found to be more stable than the others according to quantum calculations.

CONCLUSIONLeucogen have four diastereomers in solution state and it can transform from one diastereomer to the others, and the 3R4S5R is more stable than the others.

Chromatography, Liquid ; Magnetic Resonance Spectroscopy ; Molecular Structure ; Quantum Theory ; Solutions ; Spectrometry, Mass, Electrospray Ionization ; Stereoisomerism ; Thiazolidines ; analysis ; chemistry

OBJECTIVETo study the biological exposure index of carbon disulfide in China.

METHODSHigh-performance liquid chromatography (HPLC) was used to detect the levels of 2-thiothiazolidine-4-carboxylic acid (TTCA) in the urine of the workers after working shift end, Gas chromatography was used to detect the concentrations of the carbon disulfide in the workplace air. The relationship between the urine TTCA levels and the concentrations of the carbon disulfide was analyzed, the biological exposure index and judgement result from PC-TWA were compared.

RESULTSThe levels of TTCA in urine of workers occupationally exposed to carbon disulfide were closely and positively related with the concentrations of the carbon disulfide in the workplace air. The regression equation was Y = 0.265X - 0.165, The biological exposure index of carbon disulfide were calculated by regression equation according to occupational exposure limits of carbon disulfide in China.

CONCLUSIONThe biological exposure index of CS(2) in China might be revised for 1.2 mg/g Cr.

Carbon Disulfide ; analysis ; Chromatography, Gas ; Environmental Monitoring ; Humans ; Occupational Exposure ; analysis ; Thiazolidines ; urine ; Threshold Limit Values ; Workplace

OBJECTIVETo evaluate the efficacy and safety of sodium copper chlorophyllin (trademarked as "Yebaike Tablet which is abbreviated as YBK in treating leukopenia.

METHODSOne hundred and five patients with leukopenia caused by various factors were randomized into 3 groups. The 60 patients in the YBK group took orally YBK Tablets at the dose of 40 mg, three times per day, the 30 patients in the leucogen group were treated with Leucogen Tablets at the dose of 20 mg, three times per day, and the 15 patients in the placebo group were administered with vitamin C tablets 100 mg, three times per day. All the subjects were treated for 1 month. The change of peripheral leucocytes count after treatment and adverse drug reaction that occurred in patients were studied.

RESULTSIn the 60 patients treated with YBK, the treatment proved to be markedly effective in 34 cases, effective in 17 and ineffective in 9, the total effective rate being 85%, which was significantly higher than that in the placebo group (26.7%, P < 0.01) and similar to that in the leucogen group (83.3%, P > 0.05). No adverse reaction was found in the treatment course.

CONCLUSIONYBK can be used in the treatment of leukopenia caused by various factors, satisfactory in efficacy and safe in use.

Adolescent ; Adult ; Ascorbic Acid ; administration & dosage ; Chlorophyllides ; administration & dosage ; adverse effects ; Female ; Humans ; Leukocyte Count ; Leukopenia ; drug therapy ; Male ; Middle Aged ; Tablets ; Thiazoles ; administration & dosage ; Thiazolidines ; Treatment Outcome

OBJECTIVE: To observe the protective effects of epalrestat (EPS) on interstitial fibrosis in unilateral ureteral obstruction (UUO) rats and its mechanism. METHODS: Rats were randomly divided into four groups: sham group, UUO group, UUO + epalrestat (50 or 100 mg/kg), 8 rats in each group.Rats in UUO and UUO + epalrestat group were obstructed left ureter.In the sham group, rats had their left ureters exposed and manipulated without ligation.Animals for epalrestat treatment received daily drug via gavage for 3 weeks, the rats of sham and UUO groups received equal amount of sodium carboxymethyl cellulose with the same regimen.Renal tissues pathological changes and collagen deposition were observed by HE and Masson's staining.The aldose reductase(AR) expression in renal tissues was measured by immunohistochemisty.The expression levels of collagen I, collagen III, alpha-smooth muscle actin (α-SMA), fibroblast-specific protein1 (FSP-1), fibronectin (FN), epithelial cadherin (E-cadherin), transforming growth factor-β1 (TGF-β1) and AR from kidney tissues were measured by real-time RT-PCR or Western blot. RESULTS: Compared with the sham group, the renal tissues of the UUO group showed significant fibrosis, including renal tubular epithelial cell atrophy and vacuolated degeneration, collagen deposition, fibroblasts and myofibroblasts proliferation and inflammatory cell infiltration, and concomitantly with the expressions of collagen I, collagen III, TGF-β1, AR, α-SMA, FSP-1 and FN were remarkably up-regulated, but E-cadherin was significantly reduced in UUO group.Compared with the UUO group, after 3 weeks epalrestat administration, the level of renal interstitial fibrosis was obviously ameliorated and the expressions of collagen I, collagen III, TGF-β1, AR, α-SMA, FSP-1 and FN were remarkably down-regulated, but E-cadherin was significantly increased in rats of epalrestat groups. CONCLUSION These results suggest that epalrestat attenuates renal interstitial fibrosis possibly through inhibition of EMT via inhibiting TGF-β1 and AR expression.
Animals ; Enzyme Inhibitors ; pharmacology ; Fibrosis ; complications ; drug therapy ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Rhodanine ; analogs & derivatives ; pharmacology ; Thiazolidines ; pharmacology ; Ureteral Obstruction ; complications ; drug therapy

OBJECTIVETo study the impact of the chloride channel dysfunction of the cystic fibrosis transmembrane conductance regulator (CFTR) on the cytoskeleton of Sertoli cells in the mouse.

METHODSTM4 Sertoli cells were cultured and treated with CFTR(inh)-172 at the concentrations of 1, 5, 10 and 20 μmol/L for 48 hours. Then the cytotoxicity of CFT(inh)-172 was assessed by CCK-8 assay, the expressions of F-actin and Ac-tub in the TM4 Sertoli cells detected by immunofluorescence assay, and those of N-cadherin, vimentin and vinculin determined by qPCR.

RESULTSCFTR(inh)-172 produced cytotoxicity to the TM4 Sertoli cells at the concentration of 20 μmol/L. The expressions of F-actin and Ac-tub were decreased gradually in the TM4 Sertoli cells with the prolonging of treatment time and increasing concentration of CFTR(inh)-172 (P < 0.05). The results of qPCR showed that different concentrations of CFTR(inh)-172 worked no significant influence on the mRNA expressions of N-cadherin, vimentin and vinculin in the Sertoli cells.

CONCLUSIONThe CFTR chloride channel plays an important role in maintaining the normal cytoskeleton of Sertoli cells. The reduced function and expression of the CFTR chloride channel may affect the function of Sertoli cells and consequently spermatogenesis of the testis.

Actins ; metabolism ; Animals ; Benzoates ; pharmacology ; Chloride Channels ; physiology ; Cystic Fibrosis Transmembrane Conductance Regulator ; antagonists & inhibitors ; Cytoskeleton ; drug effects ; Male ; Mice ; Sertoli Cells ; drug effects ; metabolism ; Spermatogenesis ; Thiazolidines ; pharmacology ; Time Factors