[The method of determination for 2, 3-Butanedione in the air of workplace by high performance liquid chromatography with derivatization].

Objective: To establish a method for the determination of 2, 3-Butanedione (BUT) in the air of workplace, which including the process of collection by absorption in phosphoric acid aqueous solution and the process of analysis and detection by high performance liquid chromatography with derivatization. Methods: In October 2022, a porous glass plate absorption tube containing 10 ml of 0.01% phosphoric acid solution was used to collect BUT in the air of the workplace at a flow rate of 0.2 L/min. The absorption solution was derived by 2, 4-dinitrophenylhydrazine for 75 min and separated on a SB-C18 column (250 mm×4.6 mm, 5 µm) . At the column temperature of 30 ℃, the mixture of acetonitrile-water (V∶V, 1∶1) was eluted at the flow rate of 1.0 ml/min. It was detected by UV detector (λ=365 nm) , qualitatived by retention time and quantitatived by external standard. Results: It showed that BUT in phosphoric acid aqueous solution could be stored for at least 7 d at 4 ℃. There was a linear relationship within the determination range of 0.05-6.00 µg/ml, the linear regression equation was y=89.610x+0.133, r=0.9999. The sampling absorption efficiencies were 98.33%-100.00%, the detection limit of the method was 0.005 µg/ml, the minimum detection concentration was 0.016 mg/m(3) (based on V(0)=3.0 L) . The recovery rates were 95.96%-102.44%, the intra batch precision were 4.36%-7.78%, and the inter batch precision were 4.96%-6.06%. Conclusion: The method has the advantages of simple operation, high sensitivity and good accuracy. It can prevent the loss and degradation of BUT. It can be used for the determination of BUT in the air of workplace.

[Meta-analysis on the contents of trace elements in workers with occupational exposure to lead].

Objective: To quantitatively evaluate the content differences of trace elements in workers with occupational exposure to lead. Methods: In January 2021, relevant literatures on the contents of trace elements in workers with occupational exposure to lead published from 1990 to 2020 were searched through CNKI, Wanfang, VIP, PubMed, web of science and Embase. Screened and extracted the literatures, and evaluated the quality of the included literatures with Newcastle Ottawa Scale. Meta analysis was performed with Review Manager 5.3 software, and standardized mean difference (SMD) and its 95% confidence interval were used as effect indicators. Results: A total of 20 literatures were included, and the quality scores were 5-7. The results of Meta-analysis showed that compared with the control group, the contents of blood zinc (SMD=-1.01, 95%CI: -1.53, -0.49) , hair zinc (SMD=-0.17, 95%CI: -0.33, -0.01) , hair copper (SMD=-0.50, 95%CI: -1.01, 0) , hair iron (SMD=-3.91, 95%CI: -5.80, -2.03) and hair manganese (SMD=-1.09, 95%CI: -2.02, -0.15) in occupational lead exposure group were significantly lower (P<0.05) . Compared with the control group, the content of cobalt in hair of occupational lead exposure group (SMD=1.41, 95%CI: 0.72, 2.10) was higher, and the difference was statistically significant (P<0.05) . There was no significant difference in the contents of blood chromium, blood copper, blood iron, blood manganese, blood selenium and hair nickel between the two groups (P>0.05) . Conclusion: Workers with occupational exposure to lead have abnormal trace elements.

[Determination of methyl isobutyl ketone in urine by headspace coupled with gas chromatography-mass spectrometry].

Objective: To establish a method for the determination of methyl isobutyl ketone (MIBK) in urine samples by headspace-gas chromatography-mass spectrometry. Methods: Automatic headspace sampling technique was adopted to optimize the headspace conditions (headspace bottle heating temperature and equilibration time) and gas chromatographic conditions. A total of 5 ml samples were taken and added with 3.0 g ammonium sulfate into a 20 ml headspace bottle. After heated at 60 ℃ for 30 mins, gas from the upper part of headspace bottle was injected into gas chromatography with an injection volume of 100 µl. The target was separated by HP-5MS UI (30 m×0.25 mm×0.25 µm) capillary column and then detected by mass spectrometry detector. The retention time and external standard method were used for qualitative and quantitative analysis of MIBK in samples, respectively. Results: The standard curve of MIBK showed significant linearity between 20.0-1 000.0 µg/L. The standard curve was y=62.9x-652.5, and the correlation coefficient r=0.9998. The detection limit of MIBK was 5.0 µg/L and the quantification limit of MIBK was 16.0 µg/L. The average recovery rate was 95.3%~100.2% at three spiked concentrations of low (50.0 µg/L) , medium (200.0 µg/L) and high (500.0 µg/L) . The intra-day and inter-day precisions were 1.7%~3.8% (n=6) and 1.2%~4.0% (n=6) respectively. This method was stable for the determination of MIBK, and the urine could be kept 14 d at -20 ℃ without significantly loss. Conclusion: This method is proved to be simple, practical and highly sensitive. It can satisfy the request for the determination of urine samples of workers exposed to MIBK.

TRPP2 promotes the proliferation of nasopharyngeal carcinoma through upregulating Skp2/c-Myc.

OBJECTIVE: To elucidate the promotive role of TRPP2 in nasopharyngeal carcinoma (NPC) proliferation by targeting Skp2/c-Myc, thus accelerating the malignant progression. PATIENTS AND METHODS: TRPP2 levels in NPC patients with different T stages were detected. Correlation between TRPP2 level and clinical features of NPC patients was analyzed. Kaplan-Meier curves were depicted for assessing the prognostic value of TRPP2 in NPC. Subsequently, regulatory effects of TRPP2 on viability and 5-ethynyl-2'-deoxyuridine (EdU)-positive ratio were determined by cell counting kit-8 (CCK-8) and EdU assay, respectively. Relative levels of Skp2 and c-Myc in NPC cells transfected with si-TRPP2 were examined. At last, the involvement of c-Myc in TRPP2-regulated proliferative ability of NPC was evaluated by performing rescue experiments. RESULTS: TRPP2 was upregulated in NPC tissues. TRPP2 level was higher in NPC patients with T3+T4 than those with T1+T2. Worse survival was observed in NPC patients expressing high level of TRPP2. TRPP2 level was correlated to T stage, N stage, M stage, and locoregional failure of NPC patients. Knockdown of TRPP2 reduced viability and EdU-positive ratio in NPC cells. In addition, relative levels of Skp2 and c-Myc in NPC cells transfected with si-TRPP2 were downregulated. Overexpression of c-Myc could partially reverse the regulatory effects of TRPP2 on NPC proliferation. CONCLUSIONS: TRPP2 stimulates NPC cells to proliferate by upregulating expressions of Skp2/c-Myc, thus deteriorating the development of NPC.

[Determination of the butanone in urine by gas chromatography with precolumn derivation].

Objective: To establish a method for determination of the butanone in urine by gas chromatography (GC) with pre-column derivation. Methods: For detecting of butanone in urine, potassium iodide and potassium dichromate were added into urine under acidic condition, sample derivatization was undertaken in 50 ℃ water bath for 60 min and the iodine butanone was extracted with n-hexane. After the sodium thiosulfate solution was used to remove excess iodine, urine samples were centrifuged at 10000 r/min for 5 min, then the supernatant was analyzed using temperature rising programming with the Agilent Hp-5 column (30 m×0.32 mm, 0.25 µm) and electron capture detector (ECD) as the detector. The detector temperature was 300 ℃, the inlet temperature was 200 ℃, and the carrier gas was nitrogen. Results: For detecting of butanone in urine, potassium iodide and potassium dichromate were added for derivatization under the acidic condition. After extraction and centrifugation, the supernatant directly put through column and detected by ECD. In present study, the sample pretreatment condition was optimized, the relative standard deviations of intra-day and inner-day, the spiked samples and its recovery were evaluated for analyzing the accuracy of the proposed method. Conclusion: This method has proved to be simple, efficient and highly sensitivity, it can be utilized for butanone detection in occupational population.

[Applications of the Fe(3)O(4) nanocomposite modified by Humic Acid in determination of S-phenylmercapturic acid in urine by dispersive solid-phase extraction and HPLC].

Objective: To establish a method for determination the S-phenylmercapturic acid in urine by dispersive solid-phase extraction using Humic Acid/Fe(3)O(4) magnetic nanocomposite as adsorbent. Methods: The 5 ml of urine samples were adjusted to pH 1.0 and extracted by Fe3O4@HA. Then the analytes were separated on EC-C(18) capillary column and detected by HPLC-VWD. The S-phenylmercapturic acid was characterized by the retention time and quantified by peak area and external standard method. Results: The standard curves of SPMA showed significant linearity between 0.04~1.00 mg/L (r=0.999 7) . The average recovery was 94.2%~102.4%. The intra-day and inter-day precisions (RSD) were 2.9~6.7% (n=6) and 3.1~7.5% (n=6) respectively. The detect limit of SPMA was 0.012 g/L (S/N=3) . Conclusion: This method is simple, rapid, sensitive and accurate. It is applicable for determination of SPMA in the urine of works who were exposed to benzene.

Over-expression of MEOX2 promotes apoptosis through inhibiting the PI3K/Akt pathway in laryngeal cancer cells.

The early-stage diagnosis and treatment for the recurrence of larynx carcinoma needs further investigation. Mesenchyme homeobox 2 (MEOX2) was speculated as a novel suppressor gene in larynx carcinoma in our study, the molecular mechanism was studied. Real-time quantitative PCR (RT-qPCR) and Western blot were used to detect mRNA and protein levels of MEOX2 in laryngeal cancer tissues and cells (Hep-2, TU212, AMC-NH-8 and TU686 cells), and also apoptosis and phosphoinositide 3-kinase (PI3K)/protein kinase (Akt) related factors in TU212 cells transfected with MEOX2. Cell counting kit-8 (CCK8) assay and Annexin-Ⅴ/PI staining assay were conducted to determine cell viability and apoptosis rates respectively.46 patients with larynx carcinoma were involved in this study. The expression of MEOX2 was lower in larynx carcinoma tissues than normal tissues, correlated with clinical stages, differentiated degrees, and survival times. The expression of MEOX2 was the lowest among those laryngeal cancer cells, and was chosen to be transfected with MEOX2 in the following study. Over-expression of MEOX2 inhibited cell viability and promoted apoptosis of TU212 cells, via increasing the expression levels of Caspase-3, and decreasing levels of C-Myc, XIAP, PI3K p110α, PI3K p110ß, PI3K class III and p-Akt. In summary, the expression levels of MEOX2 were inhibited in larynx carcinoma than normal tissues, correlated with the progression of the cancer. Over-expression of MEOX2 in laryngeal cancer cells inhibited cell viability and promoted apoptosis, via regulating apoptosis and PI3K/Akt pathway related factors. It would provide evidence for MEOX2 to be used as a therapeutical gene in larynx carcinoma.

[Giant cell reparative granuloma originating from the paranasal sinus: a case report].

A 40-year-old man presented with a 10-year history of nasal obstruction of his left nose, a 1-year history of headache and orbital pain. Radiologically, an extensive paranasal sinus mass was seen. Superiorly ,the cribriform plate was demineralized, and the lesion had intracranial extension with mild mass effect over the basal frontal lobes. Histologic examination revealed a central giant cell reparative granuloma. After endoscopic removal, the patient was symptom free at the 2-month follow-up.

[Simultaneous determination of trichloroethylene and trichloroethanol in blood by liquid-liquid extraction-gas chromatography].

Objective: To establish a method for determing the trichloroethylene(TCE)and trichloroethanol(TCOH)in blood samples by liquid-liquid extraction-gas chromatography with electron capture detector. Methods: With this method,ether was used as extraction solvent and trichloromethane was used as an internal standard. The whole blood sample was extracted with ether, and dehydrated by anhydrous sodium sulfate. Then the analytes were separated on HP-5 capillary column(30m×0.32mm×0.15µm)and detected byECD.The retention time was for qualitative analysis and the internal standard was for quantitation. Results: The standard curves of TCE and TCOH showed significant linearity between 95.5µg/L-7640.0µg/L(r=0.9997)and 19.0µg/L-1520.0µg/L(r=0.9992). The average recovery was 95.5%-103.6%.The intra-day and inter-day precisions(RSD)were 2.5%-6.8%(n=6)and 1.6%-4.3%(n=6) respectively. The detect limit of TCE and TCOH were 2.10 µg/L and 0.56µg/L(S/N=3)respectively.The blood can be kept 7 days at-20℃ refrigerator without significantly loss. Conclusion: This method is proved to be simple,practical and highly sensitive. It can satisfy the request for the determination of blood samples of humans exposed to TCE.

[Chromosome aberration and micronucleus frequency in peripheral blood lymphocytes in radiation workers].

OBJECTIVE: To investigate chromosome aberration and micronucleus frequency in peripheral blood lymphocytes in workers engaged in radiation for a long time, to reduce occupational hazard caused by ionizing radiation, and to further strengthen health surveillance. METHODS: A total of 366 members of medical staff engaged in radiation work who underwent physical examinations in Hangzhou Hospital of Prevention and Treatment of Occupation Diseases from 2014 to 2015 were enrolled as radiation group, consisting of staff engaged in X-ray diagnosis, diagnostic radiology, radiotherapy, and interventional radiology. Another 100 members of medical staff without exposure to radiation were enrolled as control group. Whole blood culture was used to measure chromosome aberration and micronucleus frequency in peripheral blood lymphocytes. RESULTS: The radiation group had a significantly higher rate of chromosome aberration than the control group (0.30% vs 0.09% , χ(2)= 13.43, P<0.01), as well as a significantly higher micronucleus frequency than the control group (2.09‰ vs 0.08‰, χ(2)=74.4, P<0.01). The abnormal rates of chromosome aberration and micronucleus showed no significant differences across radiation workers with different working years (P>0.05). The staff engaged in X-ray diagnosis, diagnostic radiology, radiotherapy, and interventional radiology had rates of chromosome aberration of 0.25%, 0.25%, 0.23%, and 0.41%, respectively, which showed a significant difference between the staff at these four posts (χ(2)=8.22, P<0.05); the micronucleus frequencies in the staff at these four posts were 1.36‰, 1.28‰, 1.14‰, and 3.79‰, respectively, and showed a significant difference between the staff at these four posts (χ(2)=251.09, P<0.01). CONCLUSION: Radiation workers are exposed to lowdose ionizing radiation for a long time, which may cause significant increases in the rate of chromosome aberration and micronucleus frequency in peripheral blood lymphocytes.

A spin labeling study of pig cardiac tropomyosin.

Tropomyosin (TM) extracted from pig cardiac muscle was spin-labeled with 2,2,6,6-tetramethyl-4-(dichlorotriazin)-aminopiperidine-1-oxyl. The ESR spectra of the product (SL-TM) were of a type of weak immobilization. Effects of three means for the denaturation were observed on the above spectra. The ESR spectrum obtained for SL-TM after enzymatic degradation was found to be analogous to that for the label itself in a dilute solution and thereby the quantity of labels bound in SL-TM estimated. The Arrhenius plots attained through variable temperature measurement for SL-TM's exhibited two inflexion points (the conformational transition temperatures for TM) around 45 degrees C and 74-75 degrees C, the latter temperature having not been reported in literature so far. However, the enzymatic degradation product from SL-TM behaved quite differently from it in the response to microwave power saturation and temperature variation.