Progress on the relationship between hyperoxia exposure and renal development in premature infants / 国际儿科学杂志

Oxygen therapy is a common therapeutic method to improve oxygenation of premature infants, but long-term exposure to high oxygen can cause damage to immature organs and abnormal development.In addition to bronchopulmonary dysplasia and retinopathy, high oxygen levels will increase the risk of chronic kidney disease and hypertension in adulthood.High oxygen exposure can lead to kidney damage and developmental abnormalities in premature infants, including reduced number and increased volume of glomeruli, renal cell apoptosis, and abnormal development of renal tubules.The mechanism may be related to abnormal signaling pathways related to renal development.This article reviews the relationship between hyperoxia and kidney development and the possible mechanism of kidney disease, in an attempt to provide theoretical reference for early clinical intervention.

The role of hyperoxia-induced cellular senescence in bronchopulmonary dysplasia / 国际儿科学杂志

Bronchopulmonary dysplasia(BPD)is a chronic respiratory system disease that causes respiratory failure and death in premature infants, and hyperoxic exposure is the main risk factor for its occurrence.Cellular senescence describes a state of cell cycle blockade, and in recent years studies have confirmed that exposure to hyperoxia can cause cellular senescence.Cellular senescence plays a crucial role in the development of the lung epithelium, lung interstitium, pulmonary vasculature, and airways, and abnormal development of these tissues is associated with the development of BPD.Therefore, this paper takes cellular senescence and BPD as the starting point to review the mechanism of hyperoxia-induced cellular senescence in the occurrence and development of BPD and the anti-aging drugs currently applied in clinical practice, in order to provide a new direction for the prevention and treatment of BPD.

Intense venous reflux, quantified by a new software to analyze presurgical ultrasound, is associated with unfavorable outcomes of microsurgical varicocelectomy / 亚洲男科学杂志(英文版)

The hemodynamic characteristics of venous reflux are associated with infertility in patients with varicocele; however, an effective method for quantifying the structural distribution of the reflux is lacking. This study aimed to predict surgical outcomes using a new software for venous reflux quantification. This was a retrospective cohort study of a consecutive series of 105 patients (age range: 22-44 years) between July 2017 and September 2019. Venous reflux of the varicocele was obtained using the Valsalva maneuver during scrotal Doppler ultrasonography before microsurgical varicocelectomy. Using this software, the colored reflux signals were segmented, and the gray scale of the color pixels representing the reflux velocity was comprehensively quantified into the mean reflux velocity of the green layer (MRVG) and the reflux velocity standard deviation of the green layer (RVSDG). Spontaneous pregnancy and changes from baseline in the semen parameters were assessed during a 12-month follow-up period. Data were analyzed using logistic regression analysis. An association of the high MRVG group with impaired progressive motility (odds ratio [OR] = 2.868, 95% confidence interval [CI]: 1.133-7.265) and impaired sperm concentration (OR = 2.943, 95% CI: 1.196-7.239) was found during multivariate analysis. High MRVG (OR = 2.680, 95% CI: 1.086-6.614) and high RVSDG (OR = 2.508, 95% CI: 1.030-6.111) were found to be independent predictors of failure to achieve pregnancy following microsurgical repair. In summary, intense venous reflux is an independent predictor of impaired progressive motility, sperm concentration, and pregnancy outcomes after microsurgical varicocelectomy.

Insulin resistance in women with recurrent miscarriage: a systematic review and meta-analysis.

PURPOSE: This review aimed to investigate the association of insulin resistance (IR) in women with recurrent pregnancy loss compared to women with normal pregnancy history. METHODS: PubMed, EMBASE, the Web of Science and Google Scholar databases were accessed to collect published observational studies that compared IR of recurrent pregnancy loss women with healthy women until the 6th of October 2022. Outcomes assessed in this review and meta-analysis included fasting blood glucose, fasting plasma insulin, homeostasis model assessment for IR, glucose to insulin ratio. Mean differences, odds ratios with 95% confidence interval were pooled using the fixed or random effect models. Sensitivity analyses were performed to validate the robustness of the results. Review Manager version 5.4.1 and Stata version 8.0 were used. RESULTS: A total of nineteen studies involving 4453 individuals were included. Recurrent pregnancy loss patients presented significantly higher fasting blood glucose, fasting plasma insulin, homeostasis model assessment for IR, and lower glucose to insulin ratios. Additionally, recurrent pregnancy loss patients had higher rates of IR as defined by abnormal fasting plasma insulin, homeostasis model assessment for IR, and glucose to insulin ratio. Sensitivity analyses validated the robustness of the results. CONCLUSION: In the current review, we show that recurrent pregnancy loss is associated with a higher degree of IR and highlight the importance of screening and treatment of IR.

Association between Uric Acid and In-Hospital Heart Failure in Patients with Acute Myocardial Infarction Undergoing Percutaneous Coronary Intervention.

OBJECTIVE: To investigate the association of serum uric acid levels with in-hospital heart failure (HF) in patients with acute myocardial infarction (AMI) who are undergoing percutaneous coronary intervention (PCI). METHODS: Two hundred sixteen patients with AMI who were treated with PCI were enrolled in our study. Univariate and multivariate logistic regression analyses were performed to estimate the associations between uric acid levels and the risk of in-hospital HF in AMI patients. Analyses of the areas under the receiver operating characteristic (ROC) curve were performed to determine the accuracy of uric acid levels in predicting in-hospital HF. RESULTS: A dose-response relationship was found for the incidence of in-hospital HF and levels of uric acid, showing increased HF from the lowest to the highest tertile of uric acid. Compared with subjects in the bottom tertile, the adjusted odds ratio for in-hospital HF was 1.92 (95% CI 0.70-5.24) and 3.33 (95% CI 1.18-9.46) in the second tertile group and the third tertile group, respectively. Every 1 mg/dl increase in the serum uric acid level was associated with a 1.60-fold increased risk of incident in-hospital HF (OR, 1.60; 95% CI 1.22-2.11; P = 0.001). ROC curve analysis showed that the optimal cut-off value of uric acid to predict in-hospital HF was 5.75 mg/dl with a sensitivity of 69.2% and specificity of 56.3%. CONCLUSIONS: Our study showed that the serum uric acid level on admission is an independent predictor of in-hospital heart failure in patients with AMI.

Celebrex adjuvant therapy on COVID-19: An experimental study

BackgroundThe world is under serious threat with the spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes the coronavirus disease 2019 (COVID-19). However, there is no effective drug for the treatment of COVID-19. Based on analyses of available data, we deduced that the excessive prostaglandins E2 (PGE2) accumulation mediated by cyclooxygenase-2 (COX-2) was the key pathological basis of COVID-19. MethodsThe urine PGE2 levels were measured by mass spectrometry. An experimental study about Celebrex to treat COVID-19 was conducted based on routine treatment. A total of 44 confirmed COVID-19 patients were enrolled (Experimental group n=37, Control group n=7). Patients in experimental group were given Celebrex once or twice a day (0.2 g/time) for 7-14 days. The dosage or duration was modified for individuals. Clinical outcomes of Celebrex adjuvant therapy were evaluated by vital signs, laboratory tests, and computed tomography upon the discontinuance of Celebrex. ResultsWe found that the concentrations of PGE2 in urine samples of COVID-19 patients were significantly higher than that of healthy individuals (mean value is 170 ng/ml vs 18.8 ng/ml, p<0.01) and positively correlated with the progression of COVID-19. Among the experimental group (ordinary n=29, severe n=7, critical n=1), 25 cases were treated with full dose and 11 cases with half dose of Celebrex, and 1 case with Ibuprofen. The remission rate were 100%, 82% and 57% in full dose, half dose and control group respectively. Celebrex significantly reduced the PGE2 levels and promoted recovery of ordinary or severe COVID-19. ConclusionOur study suggests that Celebrex adjuvant treatment may be helpful for the therapy of COVID-19.

A microRNA disease signature associated with lymph node metastasis of lung adenocarcinoma.

Background: Lymph node metastasis (LNM) of lung cancer is an important factor associated with prognosis. Dysregulated microRNAs (miRNAs) are becoming a new powerful tool to characterize tumorigenesis and metastasis. We have developed and validated a miRNA disease signature to predict LNM in lung adenocarcinoma (LUAD). Method: LUAD miRNAs and clinical data from The Cancer Genome Atlas (TCGA) were obtained and divided randomly into training (n = 259) and validation (n = 83) cohorts. A miRNA signature was built using least absolute shrinkage and selection operator (LASSO) (λ =-1.268) and logistic regression model. The performance of the miRNA signature was evaluated using the area under curve (AUC) of receiver operating characteristic curve (ROC). We performed decision curve analysis (DCA) to assess the clinical usefulness of the signature. We also conducted a miRNA-regulatory network analysis to look for potential genes engaged in LNM in LUAD. Result: Thirteen miRNAs were selected to build our miRNA disease signature. The model showed good calibration in the training cohort, with an AUC of 0.782 (95% CI: 0.725-0.839). In the validation cohort, AUC was 0.691 (95% CI: 0.575-0.806). DCA demonstrated that the miRNA signature was clinically useful. Conclusion: The miRNA disease signature can be used as a noninvasive method to predict LNM in patients with lung adenocarcinoma objectively and the signature achieved high accuracy for prediction.

Silencing of ATP2B1-AS1 contributes to protection against myocardial infarction in mouse via blocking NFKBIA-mediated NF-κB signalling pathway.

Myocardial infarction (MI) is an acute coronary syndrome that refers to tissue infarction of the myocardium. This study aimed to investigate the effect of long intergenic non-protein-coding RNA (lincRNA) ATPase plasma membrane Ca2+ transporting 1 antisense RNA 1 (ATP2B1-AS1) against MI by targeting nuclear factor-kappa-B inhibitor alpha (NFKBIA) and mediating the nuclear factor-kappa-B (NF-κB) signalling pathway. An MI mouse model was established and idenepsied by cardiac function evaluation. It was determined that ATP2B1-AS1 was highly expressed, while NFKBIA was poorly expressed and NF-κB signalling pathway was activated in MI mice. Cardiomyocytes were extracted from mice and introduced with a series of mouse ATP2B1-AS1 vector, NFKBIA vector, siRNA-mouse ATP2B1-AS1 and siRNA-NFKBIA. The expression of NF-κBp50, NF-κBp65 and IKKß was determined to idenepsy whether ATP2B1-AS1 and NFKBIA affect the NF-κB signalling pathway, the results of which suggested that ATP2B1-AS1 down-regulated the expression of NFKBIA and activated the NF-κB signalling pathway in MI mice. Based on the data from assessment of cell viability, cell cycle, apoptosis and levels of inflammatory cytokines, either silencing of mouse ATP2B1-AS1 or overexpression of NFKBIA was suggested to result in reduced cardiomyocyte apoptosis and expression of inflammatory cytokines, as well as enhanced cardiomyocyte viability. Our study provided evidence that mouse ATP2B1-AS1 silencing may have the potency to protect against MI in mice through inhibiting cardiomyocyte apoptosis and inflammation, highlighting a great promise as a novel therapeutic target for MI.

Analysis on epidemic characteristics of COVID-19 in Qingpu District of Shanghai / 上海预防医学

Objective To analyze epidemic characteristics of COVID-19 epidemic in Qingpu District of Shanghai and provide evidence for prevention and control of COVID-19. Methods The COVID-19 cases diagnosed in the medical facilities in Qingpu District were included in the study.Descriptive epidemiology was employed to describe diagnosis, clinical symptoms and possible exposure. Results There were 53 suspected cases identified in Qingpu District, 47 of which were excluded and 6 were confirmed.Two confirmed cases were identified when seeking medical treatment and 4 by other means.Of the confirmed cases, 83.3% were male and 66.7% were imported.Their initial symptom was mainly cough.The 75.0% of the confirmed cases had underlying diseases.By PCR testing of SARS-CoV-2, 100.0% of the sputum specimens tested positive, 50.0% of the nasopharyngeal swabs were positive, whereas 100.0% of the throat swabs were negative. Conclusion COVID-19 is more common in men than in women.The positive rate of SARS-CoV-2 in sputum samples is highest, followed by nasopharyngeal swabs and throat swabs.It is crucial to implement the countermeasures at earlier stages, such as strengthening the road entrance monitoring, at-home or intensive health observation of foreign visitors for early identification of suspected COVID-19 cases.

Rapid magnetic solid-phase extraction based on alendronate sodium grafted mesoporous magnetic nanoparticle for the determination of trans-resveratrol in peanut oils.

In the present study, a rapid and effective method based on alendronate sodium grafted mesoporous magnetic nanoparticle (Fe3O4@ANDS) extraction for the determination of trans-resveratrol (TRA) in peanut oils was developed by coupling with HPLC-UV detection. The Fe3O4@ANDS was prepared via Lewis acid/base interaction which was simply carried out in mild aqueous condition without the using of organic solvent. The resultant Fe3O4@ANDS encompassed amino group on its surface, and it was employed as magnetic solid-phase extraction adsorbent for purification and enrichment of TRA from peanut oils through hydrogen bond interaction. Under the optimized conditions, the whole pretreatment process could be accomplished within 10 min without time-consuming concentrated and reconstituted process. The linearity range of the proposed method was 1-10,000 ng/g with satisfactory correlation coefficient (R2) of 0.9992. The recoveries in spiked oil samples were in the range of 78.6-118.9% with the RSDs less than 3.3% (intra-day) and 15.2% (inter-day). The limit of detection for TRA in peanut oils was 0.3 ng/g which was comparative to the reported methods by using LC-MS/MS detection. Finally, the established method was successfully applied to the analysis of TRA in several peanut oils with different brands from local market as well as other kinds of vegetable oils.

Expression of cyclin A2 and its inhibitory factor in BPD neonatal rats and its effect on alveolar development / 国际儿科学杂志

Objective To investigate the effects of cyclinA2 and its inhibitor p21 on alveolar development in bronchopulmonary dysplasia (BPD) neonatal rats.Methods Eighty newborn rats were randomly divided into a model group (FiO2 =80％-85％) and a control group (FiO2 =21％).The degree of alveolar development was evaluated by radial alveolar count (RAC) and alveolar septal thickness.The distribution and expression of cyclinA2 and p21 were detected by immunohistochemistry and Western blot.Results The RAC value of the model group was lower than that of the control group from 3 days.The thickness of the alveolar seprum was higher than that of the control group from 7 days (P ＜0.05).The expression of p21 protein in the model group began to increase from 3d,peaked on 14d,and lasted for 21d.The expression of cyclinA2 protein in model group was higher than that in control group at 14d and 21d (P ＜0.05).There was a negative correlation between RAC and p21 protein expression in model group (r =-0.5966,P ＜0.01),and no correlation with cyclinA2 (r=0.7276,P＞0.05);there was no correlation between RAC and p21 in the control group (r =-0.2929,P ＞ 0.05),and positively correlated with cyclinA2 (r =0.8476,P ＜ 0.01).The alveolar septal thickness of the model group and the control group were both positively correlated with p 21 (r =0.4291,P＜0.05;r=0.4447,P ＜0.05),and negatively correlated with cyclinA2 (r=-0.6814,P ＜0.01;r=-0.7636,P ＜0.01).Conclusion The imbalance of cell cycle regulatory protein cyclinA2 and its inhibitor p21 expression in neonatal rats exposed to hyperoxia may be one of the related factors that interfere with the development of BPD alveoli.

Risk factors for postoperative nausea and vomiting after endoscopic retrograde cholangio-pancreatography under total intravenous anesthesia / 临床麻醉学杂志

Objective To determine the independent risk factors for postoperative nausea and vomiting (PONV) after endoscopic retrograde cholangio-pancreatography (ERCP) under total intravenous anesthesia.Methods Ninety patients,47 males and 43 females,aged 18 years old or more,falling into ASA physical status Ⅰ-Ⅲ,undergoing ERCP under total intravenous anesthesia from July 18,2016 to August 31,2016 in Ruijin Hospital were included in our study.General information and intraoperative situation of patients were collected.The incidence of PONV within 24 h was recorded.A multivariate Logistic regression model was performed to analyze the independent risk factors of PONV after ERCP under total intravenous anesthesia.Results In total,90 patients were included in this study,with 33 patients (36.7%) suffering PONV.Logistic analyses showed that female (OR=3.73,95%CI 1.36-10.27),history of PONV/motion sickness(OR=4.39,95%CI 1.40-13.76),and serum-amylase greater than 3 times the normal value (OR=5.22,95%CI 1.30-20.95) were the independent risk factors for PONV after ERCP under total intravenous anesthesia.Conclusion Female,history of PONV/motion sickness,and serum-amylase greater than 3 times the normal value were the independent risk factors for PONV after ERCP under total intravenous anesthesia.

Piezo Voltage Controlled Planar Hall Effect Devices.

The electrical control of the magnetization switching in ferromagnets is highly desired for future spintronic applications. Here we report on hybrid piezoelectric (PZT)/ferromagnetic (Co2FeAl) devices in which the planar Hall voltage in the ferromagnetic layer is tuned solely by piezo voltages. The change of planar Hall voltage is associated with magnetization switching through 90° in the plane under piezo voltages. Room temperature magnetic NOT and NOR gates are demonstrated based on the piezo voltage controlled Co2FeAl planar Hall effect devices without the external magnetic field. Our demonstration may lead to the realization of both information storage and processing using ferromagnetic materials.

[Luminescence Mechanism of Near-Infrared Quantum Dots].

Near-infrared quantum dots have unique optical properties, such as high fluorescence quantum yield, long fluorescent life, tunable fluorescence emission wavelength, half peak width and large stokes shift, resisting light bleaching etc. The advantage of "near infrared biological window" gives them great potential application value in biological fluorescent tags, solar cells, quantization calculation, photocatalysis, chemical analysis, food detection, vivo imaging and other fields. At present, the luminescence mechanism research of near-infrared quantum dots is still not comprehensive enough. In this paper, the luminescent principle of three different types of near-infrared quantum dots is summarized, including core/shell structure quantum dots (CdTe/CdSe, CdSe/CdTe/ZnSe, etc), ternary quantum dots (Cu-In-Se, CuInS2, etc) and doped quantum dots (Cu∶InP, etc). The luminescence mechanism of Type Ⅱ core/shell structure is most likely to attribute to the interband recombination luminescence, the ternary structure of quantum dots light emitting mechanism is considered to be due to the intrinsic structure defects, and the luminescence mechanism of doped quantum dots is deemed to result from the impurity defects. The existing problems of near-infrared luminescent principle of quantum dots are also discussed and their development tendency is explored t in this review. A systematic study of luminescence mechanism of near-infrared quantum dots will not only help to understand the luminescent properties of near infrared quantum dots, but also contribute to improve the synthesis methods of quantum dots with similarly high quality.

Expression of EphB4 and VEGF in esophageal cancer tissues and their relationship with microvessel density and the curative effect under thoracoscope / 重庆医学

Objective To explore the expression of EphB4 and VEGF in esophageal cancer tissues and their relationship with microvessel density (MVD ) ,and analysis the curative effect of postoperative esophageal cancer radical under thoracoscope . Methods Theexpression of EphB4 and VEGF was detected by immunohistochemistry in tumor specimens from 76 cases of esopha-geal squamous cell carcinoma and paratumor normal specimens ,used CD34 as marker to count MVD .According to the situation of expression of EphB4 and VEGF ,we analysis their relationship with lymph node metastasis rate ,recurrence and 5-year survival rate . Results The positive expression rate of EphB4 and VEGF in cancerous tissue (57 .89% and 61 .84% ) ,were significantly higher than that in tissue adjacent to carcinoma(0 and 7 .89% )(P<0 .05) .The positive expression rate ofEphB4 and VEGF in high MVD values of patients (67 .44% and 76 .19% ) ,were significantly higher than thatin low MVD values of patients (45 .45% and 44 .11% )(P<0 .05) .The positive expression rate ofEphB4 and VEGF in the patientswith lymph node metastasis group and associ-ated with recurrence ,were significantly higher than that of group without lymph node metastasis and group without recurrence (P<0 .05) .The positive expression rate of EphB4 and VEGF in patients of greater than or equal to 5 years of survival rate(45 .00% and 45 .45% ) ,were significantly lower than in patientsof Less than 5 years of survival rate (80 .36% and 85 .19% )(P<0 .05) .Conclu-sion EphB4 and VEGF are highly expressed in esophageal cancer tissue ,which may be closely associated withmicrovessel density , and lymph node metastasis ,recurrence and 5 years survival rate ;the curative effect of positive expression rate of EphB 4 and VEGF is poor .

Expression of Occludin in lung tissues of newborn rats with bronchopulmonary dysplasia and its influence on pulmonary epithelial permeability / 中华实用儿科临床杂志

Objective To explore the dynamic changes of Occludin gene and protein levels in lung tissues of newborn rats with hyperoxia-induced bronchopulmonary dysplasia (BPD) in the early phase and its effect on pulmonary epithelial permeability.Methods One hundred and sixty newborn Wistar rats were randomly assigned to hyperoxia group (900 mL/L oxygen)and normoxia group (210 mL/L oxygen) according to different oxygen concentrations,80rats in each group.Rats were sacrificed and lung tissues were removed on 1,3,5,7 d after treatment.Bronchoalveolar lavage fluid (BALF):serum FD4 ratio was detected;location and expression of Occludin were examined by immunofluorescence staining and Western blot; messenger RNA (mRNA) was studied by reverse transcription-PCR.Results There was no obvious difference in the BALF and serum FD4 ratio (1.533 ±0.122 vs 1.575 ± 0.140,P ＞ 0.05) between the hyperoxia group and the normoxia group on the first day.After 3 days of hyperoxia exposure,the ratio of FD4between BALF and serum was significantly higher than that in the normoxia group(1.365 ±0.159 vs 1.615 ±0.196,P ＜ 0.05).And after 5 or 7 days of hyperoxia exposure,the ratio of FD4 between BALF and serum was dramatically increased(1.245 ±0.152 vs 3.211 ±0.799,1.178 ± 0.594 vs 5.15 ± 0.967,all P ＜ 0.01).On the 7 day,immunofluorescence staining showed Occludin distribllted in a consecutive line along lung epithelial cell membrane in the normoxia group,while in the hyperoxia group Occludin was distributed in a discontinuous line and lacking intensity.There was no obvious difference in Occludin mRNA level between the hyperoxia group and normoxia group on the first day(2.15 ±0.33 vs 2.23 ± 0.39,P ＞ 0.05).Compared to the normoxia group,the decrease in Occludin mRNA level was statistically significant after 3 or 5 days of hyperoxia exposure(2.46 ± 0.27 vs 2.00 ± 0.19,2.62 ± 0.28 vs 2.15 ± 0.20,all P ＜ 0.05),and after 7 days of hyperoxia exposure,the Occludin mRNA level dramatically declined (3.08 ± 0.43 vs 2.01 ±0.34,P ＜0.01).There was no obvious difference in Occludin protein level between the hyperoxia group and normoxia group on the 1 st and the 3th day(1.00 ± 0.05 vs 1.05 ± 0.03,1.24 ± 0.06 vs 1.17 ± 0.04,all P ＞ 0.05).Compared to the normoxia groups,the decrease in Occludin protein level was statistically significant after 5 days of hyperoxia exposure (1.03 ± 0.04 vs 0.93 ± 0.05,P ＜ 0.05),and after 7 days of hyperoxia exposure,the Occludin protein level dramatically declined(0.96 ± 0.14 vs 0.65 ± 0.07,P ＜ 0.01).There was a significantly negative correlation between Occludin protein expression and pulmonary epithelial permeability after hyperoxia exposure (r =-0.755,P ＜0.01).Conclusions Downregulation of Occludin hyperoxia-induced may lead to the increase of pulmonary epithelial paracellular permeability,which participates in the development of pulmonary edema in the early phase of BPD induced by hyperoxia.

[The optimization of 2-thiothiazolidine-4-carboxylic acid back extraction in urine and determination by HPLC].

OBJECTIVE: Establishment of determination method of 2-thiothiazolidine-4-carboxylic acid (TTCA) in urine with HPLC. METHODS: A 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. RESULTS: TTCA 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%. CONCLUSION: The method was accurate and sensitive to detect TTCA in urine.

[The rervising of biological exposure index for carbon disulfide exposuring].

OBJECTIVE: To study the biological exposure index of carbon disulfide in China. METHODS: High-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. RESULTS: The 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. CONCLUSION: The biological exposure index of CS(2) in China might be revised for 1.2 mg/g Cr.

The optimization of 2-thiothiazolidine-4-carboxylic acid back extraction in urine and determination by HPLC / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>Establishment of determination method of 2-thiothiazolidine-4-carboxylic acid (TTCA) in urine with HPLC.</p><p><b>METHODS</b>A 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.</p><p><b>RESULTS</b>TTCA 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%.</p><p><b>CONCLUSION</b>The method was accurate and sensitive to detect TTCA in urine.</p>