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Objective To investigate the photodynamic antitumor activity and chemical characteristics of pheophorbide A (PPBa)in vitro. Methods Breast cancer cells (MCF-7), lung cancer cells (A549), cervical cancer cells (HeLa), and three kinds of hepatoma cells (HepG2, hep3B and sk-Hep1) were planted in 96-well plates.The effects of light and dark toxicity, light intensity, and drug concentration on the phototoxicity of PPBa were investigated by MTT, and the uptake of PPBa was observed by Hoechst staining under a confocal microscope.The production of singlet oxygen was observed by flow cytometry and confocal microscopy with the reactive oxygen species detection kit.The photobleaching of PPBa was investigated by measuring the absorbance by a microplate reader according to the luminescence characteristics of PPBa. Results PPBa showed strong phototoxicity and low dark toxicity to six kinds of cancer cells, and IC50 values to cancer cells were as follows: MCF-7:1.033 μmol/L, A549:1.911 μmol/L, HeLa: 2.319 μmol/L, HepG2:2.015 μmol/L, Hep3B: 2.089 μmol/L, sk-Hep1:2.467 μmol/L.The main uptake site of PPBa was the cytoplasm.The production of singlet oxygen was strongly dependent on the administration concentration, and photobleaching was very low. Conclusion For the six kinds of cancer cells, PPBa has the highest phototoxicity to breast cancer cells (MCF-7), with excellent properties and ideal photosensitizer characteristics.
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OBJECTIVE: To establish a headspace gas chromatography-mass spectrometry method for the determination of 14 chlorinated hydrocarbons in urine. METHODS: The urine sample 4.00 mL and anhydrous sodium sulfate 3.00 g were added into a 10.00 mL headspace bottle, then the headspace bottle was maintained at 70 ℃ for 40.0 min. After headspace pretreatment, 14 chlorinated hydrocarbons in headspace air were separated in the DB-5 MS capillary column of the gas chromatography and detected by mass spectrometer. RESULTS: There was a good linear relationship of 14 chlorinated hydrocarbons in urine in the range of 0.62-1 630.00 μg/L. The linear correlation coefficient was greater than 0.999 0.The minimum detectable concentration was 0.19-0.43 μg/L and the minimum quantitative concentration was 0.62-1.44 μg/L. The average recovery rate was 89.8%-107.1%. The within-run relative standard deviation(RSD) was 4.0%-8.5% and the between-run RSD was 6.3%-9.1%. Urine samples can be stored at 4 ℃ or-8 ℃ for 3 days and below-20 ℃ for 7 days. CONCLUSION: This method is rapid, simple, sensitive, accurate and has little interference,which can be used as a method for detecting 14 kinds of chlorinated hydrocarbons in urine samples of patients with occupational poisoning.
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Objective@#This study aims to explore the influence of birth order and age difference on the emotional and behavioral problems among children from two-child family, so as to provide advice on parenting.@*Methods@#A total of 482 students in grades 2 to 5 from the 5 primary schools in Guangzhou were selected, all of whom came from two-child families (excluding twin children). Emotional and behavioral problems were investigated by using the Conner’s Parental Symptom Questionnaire (PSQ).@*Results@#Among children from two-child families, higher prevalence of behavioral problems, learning problems, impulsive hyperactivity and hyperactivity index in older compared with younger children (β=-0.09，-0.16，-0.09，-0.10,P<0.05). The scores of behavioral problems and hyperactivity index were significantly higher among those of children who were 6-9 years older than young siblings, compared to those who were 0-3 years older than younger siblings(β=0.20,0.21,P<0.05). No similar pattern was found among the younger siblings(P>0.05).@*Conclusion@#Among school-age children from two-child families, emotional and behavioral problems of the elder ones were more serious than the younger ones’. Age difference between siblings shows impact on the emotional and behavioral development among elder children, however no significant impact is noticed among the younger ones.
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OBJECTIVE: To establish a method for detecting dichloromethane,trichloromethane and 1,2-dichloroethane in blood by gas chromatography-mass spectrometry. METHODS: Using static headspace analysis, three halogenated hydrocarbons in blood samples were separated by DB-5 MS elastic capillary column and detected by gas chromatographymass spectrometry. RESULTS: There was a good linear relationship in the selected range of dichloromethane,trichloromethane and 1,2-dichloroethane in blood. The linear correlation coefficient was greater than 0. 999 8. The detection limit and the lower limit of quantitation was 0. 19-0. 28 and 0. 64-0. 93 μg/L,respectively. The average recovery rate was 95. 1%-106. 6%. The within-run and between-run relative standard deviation was 2. 9%-4. 9% and 5. 0%-7. 0%,respectively. The samples could be preserved at room temperature or 4 ℃ for 3 days and at-8 ℃ or below for7 days. CONCLUSION: With the features of high sensitivity,precision,accuracy,easy operation and less interference,this method is suitable for detecting dichloromethane,trichloromethane and 1,2-dichloroethane in the blood.
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OBJECTIVE: To establish a method for detecting human urinary thiocyanate by gas chromatographic and pre-column derivatization with 2,3,4,5,6-pentafluorobenzyl bromide( PFB-Br). METHODS: A total of 20. 0 μL of urine was taken and 1. 0 m L of acetonitrile and 100. 0 μL of PFB-Br were added for derivative reaction. The gas chromatography was directly used for measurement. RESULTS: The urinary thiocyanate concentration showed a good linear range of 1. 000-10. 000 mg/L. The linear correlation coefficient was 0. 999 6. The minimum detection concentration was 0. 112 mg/L,and the minimum quantitative concentration was 0. 411 mg/L( 20. 0 μL urine sample). The standard recovery rate was 97. 22%-102. 04%.The within-run relative standard deviation( RSD) of this method was 1. 56%-5. 35%. The between-run RSD was 1. 46%-5. 10%. Hydrocyanic acid ions interfered with the measurement. Other common inorganic ions such as chloride,sulfate,and nitrate ions did not interfere with the measurement results. The samples can be stored at 4 ℃ for at least 15 days. CONCLUSION: This method is suitable for detecting human urinary thiocyanate.