Research on the effect and mechanism of hepatoma cells HepG2 exosome on its own methylation / 医学研究生学报

ObjectiveThe prognosis of patients with advanced liver cancer is poor and there is no effective treatment so far. This paper observed the effect of hepatoma cells HepG2 exosomes on its own methylation and attempted to explore its mechanism.MethodsThere was experimental group and control group in the research. The medium has been changed when the cells grow to 60% in a DMEM culture dish with 10% serum. Cells in the control group were cultured in serum-free DMEM medium while the experimental group were cultured in serum-free DMEM medium added 100 L (0.5mg/mL) exosomes, and the supernatant was retained after incubation for 48h. HepG2 cells were cultured and exosomes were extracted by overspeed differential centrifugation, and identified by particle size analysis, transmission electron microscopy, Western blot and other methods. The effect of exosomes of hepatocellular carcinoma cells HepG2 on cell proliferation was analyzed by scratch test. Fluorescence antibody staining was used to observe the change of automethylation level. Fluorescence quantitative PCR was used to detect mRNA expression levels of methyltransferase-related genes DNMT3A, DNMT3B, DNMT1, and apoptosis-related genes Bax and BcI2.ResultsUnder inverted fluorescence microscope, red fluorescent exosomes could be seen entering the cell, surrounding the blue fluorescent nucleus or on the nucleus, indicating that DiI entered the cell membrane or cytoplasm. The area ratio of 6 and 12 h in the experimental group [(57.25±2.06, 83.92±3.17) %] was significantly higher than that in the control group [(28.32±1.22, 40.03±1.74) %] (P<0.05). The genes expressions of Bax, DNMT3A and DNMT3B in the experimental group were higher than those in the control group (P<0.05). The expression of BcI2 was lower than that of the control group (P<0.05).ConclusionThe exosomes of hepatoma cell HepG2 can enhance DNA methylation level by changing the transcriptional expression of DNMT3A, DNMT3B and other genes to affect the expression of apoptose-related genes Bax and BcI2, and to promote the proliferation and growth capacity of hepatoma cell HepG2.

An investigation of oxidative DNA damage in pharmacy technicians exposed to antineoplastic drugs in two Chinese hospitals using the urinary 8-OHdG assay / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate oxidative DNA damage in pharmacy technicians preparing antineoplastic drugs at the PIVAS (Pharmacy Intravenous Admixture Service) in two Chinese hospitals.</p><p><b>METHODS</b>Urinary 8-OHdG served as a biomarker. 5-Fluorouracil (5-FU) concentrations in air, masks and gloves were determined. The spill exposure of each PIVAS technician to antineoplastic drugs was investigated. Eighty subjects were divided into exposed group I, II, and control group I, II.</p><p><b>RESULTS</b>5-FU concentration ratios for gloves and masks in exposed group I were significantly higher than those in exposed group II (P<0.05 or P<0.01). The average urinary 8-OHdG concentrations in exposed group I, control group I, exposed group II, and control group II were 14.69±0.93, 10.68±1.07, 10.57±0.55, and 11.96±0.73 ng/mg Cr, respectively. Urinary 8-OHdG concentration in exposed group I was significantly higher than that in control group I or that in exposed group II (P<0.01). There was a significant correlation between urinary 8-OHdG concentrations and spill frequencies per technician (P<0.01).</p><p><b>CONCLUSION</b>There was detectable oxidative DNA damage in PIVAS technicians exposed to antineoplastic drugs. This oxidative DNA damage may be associated with their spill exposure experience and contamination of their personal protective equipment.</p>

Investigation on occupational exposure to 5-fluorouracil in pharmacy intravenous admixture service of a hospital / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the level of occupational exposure to 5-fluorouracil (5-Fu) in the pharmacy intravenous admixture service (PIVAS) of a hospital, and identify the sources of 5-Fu contamination.</p><p><b>METHODS</b>The 5-Fu concentrations in air, on the surface of different areas in PIVAS and personal protective equipments were detected using UV-vis spectrophotometry.</p><p><b>RESULTS</b>The 5-Fu in air could not be detected. The 5-Fu concentrations on five different surfaces of biological safety cabinets were (22.00 +/- 6.35), (13.99 +/- 2.46), (14.13 +/- 0.72), (7.25 +/- 1.19) and (9.87 +/- 1.23) ng/cm2, respectively, which were significantly higher than those [(3.14 +/- 0.04), (5.43 +/- 0.65), (2.26 +/- 0.17), (2.26 +/- 0.17) and (3.63 +/- 0.46) ng/cm2] of corresponding controls (P < 0.05 or P < 0.01). The 5-Fu concentrations of the floor under cabinets [(18.19 +/- 5.22) ng/cm2], the floor in front of cabinets [(10.25 +/- 2.57)ng/cm2], the office floor [(11.64 +/- 2.53) ng/cm2], the terrace floor [(99.89 +/- 14.06 ) ng/cm2], the floor beside trash can in dressing room [(24.54 +/- 0.23) ng/cm2] were significantly higher than those of control [(3.36 +/- 0.11 ) ng/cm2] (P < 0.05 or P < 0.01). The 5-Fu concentrations of the tables in preparation room [(7.22 +/- l.04) ng/cm2] and the tables in office [(11.81 +/- 1.18) ng/cm2] were significantly higher than those of control [(5.56 +/- 0.14) ng/cm2] (P < 0.05 or P < 0.01). The 5-Fu concentrations of the indoor handle in preparation room were significantly higher than those of controls (P < 0.05 or P < 0.01). 5-Fu concentrations on the surfaces of outdoor handle and floor beside door in preparation room were not significantly increased compared with controls (P > 0.05). The 5-Fu concentrations on the surfaces of infusion bags, transfer box, transfer trays were significantly higher than those of controls (P < 0.05). The differences of 5-Fu concentrations between outer and inner masks and controls were not significant (P > 0.05). The 5-Fu concentrations of gloves of preparing and checking staffs were significantly higher than those of controls (P < 0.05 or P < 0.01).</p><p><b>CONCLUSION</b>The preparing and checking process of 5-Fu and the treatment of medical wastes are major sources of 5-Fu contamination.</p>

Using real-time PCR to evaluate the effect of viral inactivation by Methylene Blue with visible light / 病毒学报

To investigate the feasibility of using Real-Time PCR to evaluate the effectiveness of Sindbis virus inactivation by Methylene Blue with visible light. Sindbis virus was treated by Methylene Blue with different intensity of visible light and the transcribed cDNA was quantified by Real-Time PCR. Residual infectivity of treated virus was tested by cell infection method as parallel control at the same time. The residual infectivity of virus decreased from 6.50 lgTCID50/mL to under the limit of detection as light intensity increased. Meanwhile, the quantity of virus cDNA decreased significantly (P < 0.05), which correlated to the decline of virus infectivity (R2 > 0.98). Methylene Blue with visible light could cause lesion to nucleic acid of Sindbis virus, the extent of which was light intensity-dependent and correlated to the decrease of virus infectivity. The results demonstrated that Real-Time PCR can be a useful tool for evaluating effect of virus inactivation after Methylene Blue treatment with light.

Reversing effect of histamine on neuron death induced by N-methyl-D-aspartate / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To determine the effect of histamine on N-methyl-D-aspartate (NMDA) induced neuron death and to elucidate its mechanism.</p><p><b>METHODS</b>The primary cortical cell culture was adopted. Neuron morphology and MTT assay were used to evaluate the drugs effects.</p><p><b>RESULT</b>Histamine at doses of 10(-4) 10(-6) 10(-7) 10(-8) mol/L reversed the neuron death induced by NMDA (50 micromol/L) for 3 h. The protection of histamine peaked at doses of 10(-4) mol/L and 10(-7)mol/L. The effect of histamine of 10(-7) mol/L was reversed only by cimetidine an H(2)receptor antagonist. However, the effect of histamine of 10(-4) mol/L was reversed only by pyrilamine but not cimetidine.</p><p><b>CONCLUSION</b>Histamine could reduce neuron death induced by NMDA; its protection at a low dose might be mediated by H(2)receptor, and at a high dose by H(1)receptor.</p>

Improved alternative electro-stimulus Y-maze for evaluating the spatial memory of rats / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To establish an effective model for evaluating the spatial memory of rats.</p><p><b>METHODS</b>The adjacent left or right arm in Y-maze was defined as an initial arm or an objective one alternatively, and electro-stimulus to vola was used as a reinforcement. Meanwhile, the reliability of the model was validated by measuring the memory deficits induced by intraperitoneal (i.p.) injection of scopolamine (0.5 mg/kg) or bilaterally intrahippocampal (i.h.) microinjection of MK-801(0.2 microg/site).</p><p><b>RESULTS</b>The normal, sham-operated or saline-treated rats learned the left-right alternative memory model rapidly while injection of either scopolamine or MK-801 caused spatial memory deficits in Y-maze, including deficits in working and reference memory. Moreover,there was no appreciable difference in electricity intensity between the treated group and the control group.</p><p><b>CONCLUSION</b>The alternative Y-maze with electro-stimulus is a comparatively objective model which can evaluate the spatial memory in rats effectively.T</p>