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

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

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 clinical effect of pidotimod oral liquid as adjuvant therapy for infectious mononucleosis and its effect on T lymphocyte subsets.

METHODSA total of 76 children with infectious mononucleosis, who were admitted to the hospital between July 2016 and June 2017, were enrolled and randomly divided into two groups: conventional treatment and pidotimod treatment (n=38 each). The children in the conventional treatment group were given antiviral therapy with ganciclovir for injection and symptomatic treatment. Those in the pidotimod treatment group were given pidotimod oral liquid in addition to the treatment in the conventional treatment group. The course of treatment was two weeks for both groups. The two groups were compared in terms of the recovery of clinical indices and the changes in peripheral blood T lymphocyte subsets.

RESULTSCompared with the conventional treatment group, the pidotimod treatment group had significantly shorter fever clearance time, time to the disappearance of isthmopyra, time to the relief of lymph node enlargement, time to the relief of hepatosplenomegaly, and length of hospital stay (P<0.05). After treatment, the pidotimod treatment group had significant reductions in the percentages of CD3 and CD8 T cells and had significantly lower percentages of CD3 and CD8 T cells than the conventional treatment group (P<0.001). The pidotimod treatment group had significant increases in the percentage of CD4 T cells and CD4/CD8 ratio after treatment, which was significantly higher than those in the conventional treatment group (P<0.001). The conventional treatment group had no significant changes in T lymphocyte subsets after treatment (P>0.05).

CONCLUSIONSPidotimod oral liquid has a good clinical effect as the adjuvant therapy for infectious mononucleosis and can improve cellular immune function, so it holds promise for clinical application.

Adjuvants, Immunologic ; administration & dosage ; Administration, Oral ; Antiviral Agents ; administration & dosage ; CD4-CD8 Ratio ; Drug Therapy, Combination ; Female ; Ganciclovir ; administration & dosage ; Humans ; Infectious Mononucleosis ; drug therapy ; immunology ; Male ; Pyrrolidonecarboxylic Acid ; administration & dosage ; analogs & derivatives ; T-Lymphocyte Subsets ; drug effects ; immunology ; Thiazolidines ; administration & dosage ; Treatment Outcome

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

Mammalian pancreatic β-cells play a pivotal role in development and glucose homeostasis through the production and secretion of insulin. Functional failure or decrease in β-cell number leads to type 2 diabetes (T2D). Despite the physiological importance of β-cells, the viability of β-cells is often challenged mainly due to its poor ability to adapt to their changing microenvironment. One of the factors that negatively affect β-cell viability is high concentration of free fatty acids (FFAs) such as palmitate. In this work, we demonstrated that Yes-associated protein (Yap1) is activated when β-cells are treated with palmitate. Our loss- and gain-of-function analyses using rodent insulinoma cell lines revealed that Yap1 suppresses palmitate-induced apoptosis in β-cells without regulating their proliferation. We also found that upon palmitate treatment, re-arrangement of F-actin mediates Yap1 activation. Palmitate treatment increases expression of one of the Yap1 target genes, connective tissue growth factor (CTGF). Our gain-of-function analysis with CTGF suggests CTGF may be the downstream factor of Yap1 in the protective mechanism against FFA-induced apoptosis.
Actins ; metabolism ; Adaptor Proteins, Signal Transducing ; antagonists & inhibitors ; genetics ; metabolism ; Animals ; Apoptosis ; drug effects ; physiology ; Bridged Bicyclo Compounds, Heterocyclic ; pharmacology ; Cell Line, Tumor ; Connective Tissue Growth Factor ; genetics ; metabolism ; pharmacology ; Cytochalasin D ; pharmacology ; Fatty Acids, Nonesterified ; pharmacology ; HEK293 Cells ; Humans ; Immunohistochemistry ; Insulin-Secreting Cells ; cytology ; drug effects ; metabolism ; Mice ; Microscopy, Fluorescence ; Palmitic Acid ; pharmacology ; Phosphoproteins ; antagonists & inhibitors ; genetics ; metabolism ; RNA Interference ; RNA, Small Interfering ; metabolism ; Rats ; Recombinant Proteins ; genetics ; metabolism ; pharmacology ; Thiazolidines ; pharmacology

Aim of the present study is to investigate activation effect of nobiletin on cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel activity. CFTR-mediated iodide influx assay and patch-clamp tests were done on FRT cells stably co-transfected with human CFTR and EYFP/H148Q. Nobiletin potently activated CFTR chloride channel activity in a dose- and time-dependent manner. The CFTR blocker CFTR(inh)-172 could completely reverse the effect. Preliminary mechanism study indicated that nobiletin activated CFTR chloride channel through a direct binding way. In addition, ex vivo tests done on mice trachea showed that nobiletin time-dependently stimulated submucosal gland fluid secretion. Nobiletin may be a therapeutic lead compound in treating CFTR-related diseases including disseminated bronchiectasis.
Animals ; Benzoates ; pharmacology ; Cystic Fibrosis Transmembrane Conductance Regulator ; antagonists & inhibitors ; drug effects ; metabolism ; Dose-Response Relationship, Drug ; Epithelial Cells ; metabolism ; Exocrine Glands ; secretion ; Flavones ; administration & dosage ; pharmacology ; Humans ; Mice ; Patch-Clamp Techniques ; Rats ; Rats, Inbred F344 ; Thiazolidines ; pharmacology ; Thyroid Gland ; cytology ; Time Factors ; Trachea ; secretion

OBJECTIVETo study the protective effect of epalrestat against endothelial cell injuries induced by high glucose.

METHODSHuman umbilical vein endothelial cells were pretreated with epalrestat (0.1 µmol/L) for 30 min followed by exposure to high glucose for 8 h. NO concentration in the cell culture supernatant was assayed using chemiluminescence method following the exposure. Real-time PCR and Western blotting were used to detect eNOS mRNA and protein expression levels and the protein expressions of AR gene (the target gene of epalrestat) and NOX4 (the upstream gene of NO).

RESULTSCompared with mannitol treatment, an 8-h exposure to high glucose caused significantly decreased NO levels and eNOS mRNA and protein expression in the vascular endothelial cells (P<0.05). Pretreatment with epalrestat prior to high glucose exposure resulted in elevated eNOS mRNA and protein expression levels and NO up-regulation in the cell culture as compared with the glucose exposure alone group (P<0.05), causing also decreased expression of AR and NOX4 in the cells.

CONCLUSIONSHigh glucose can induce endothelial cell damage characterized by a lowered level of NO secretion. Epalrestat can protect the endothelial cells against high glucose-induced injury by inhibiting the expression of AR and NOX4.

Aldehyde Reductase ; antagonists & inhibitors ; Cells, Cultured ; Endothelium, Vascular ; drug effects ; metabolism ; Enzyme Inhibitors ; pharmacology ; Glucose ; adverse effects ; Human Umbilical Vein Endothelial Cells ; cytology ; drug effects ; Humans ; NADPH Oxidase 4 ; NADPH Oxidases ; metabolism ; Nitric Oxide Synthase Type III ; metabolism ; RNA, Messenger ; genetics ; Rhodanine ; analogs & derivatives ; pharmacology ; Thiazolidines ; pharmacology

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

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