Analysis of correlation between eye strain and eye health behavior in college students during the period of COVID-19 epidemic / 中国学校卫生

Objective@#To understand the relationship between eye strain and eye health behavior in college students learning at home during the period of COVID-19 epidemic, and to provide a scientific reference for improving the hygiene of using eyes among the college students.@*Methods@#A cross sectional study and stratified cluster sampling was used to select 2 671 college students from 8 colleges in Anhui Province during the March 1st to July 1st in 2020, and an online questionnaire was survey included general information,eye strain,and daily eye health behavior.@*Results@#The prevalence of eye strain in college students was 69.64%. Multivariable Logistic regression analysis showed that eye strain was correlated with gender, myopia, siesta habit, staying up until 2:00 am, and the use of eye liquid, with OR values(95% CI ) were 0.64(0.53-0.76), 1.77(1.42- 2.20 ),0.71(0.59-0.86), 1.39(1.17-1.65), and 2.18(1.71-2.79), respectively. There was no correlation among daily outdoor activity time, daytime reading time and the occurrence of eye strain( P >0.05).@*Conclusion@#During the period of COVID-19 epidemic, eye strain among college students is common. The daily eye health behavior is related to the occurrence of eye strain. Under the special learning context, eye care measures should be encouraged specifically.

PDA-mediated Mild Photothermal Therapy Combined with Autophagy Inhibitors Kill Breast Cancer Cells / 肿瘤防治研究

Objective To explore whether inhibiting autophagy can enhance the sensitivity of photothermal treatment under mild photothermal conditions. Methods CQ@PLGA@PDA NPs were prepared by an improved double emulsification method and a PDA-based surface modification method. After basic characterization, CCK-8 method was used to detect the cytotoxicity of nanoparticles; the near-infrared laser irradiation nanoparticle solution was used to detect the heating effect; CCK-8 method and live-dead cell staining were used to detect the killing effect of tumor cells; Western blot was used to detect the expression of autophagy-related proteins. Results The CQ@PLGA@PDA NPs were successfully prepared, with a particle size of 253.10±2.39 nm, a zeta potential of -22.57±0.80 mV, uniform particle size and good dispersion. The temperature of nanoparticle solution increased to 45℃ after the near-infrared laser irradiation for 10 min. CQ@PLGA@PDA NPs had no obvious toxicity to cells. The survival rates of breast cancer cell MDA-MB-231 and mouse embryonic fibroblast NIH-3T3 cell were above 95%. The inhibition of autophagy under mild photothermal conditions could improve the sensitivity of photothermal therapy. Conclusion The prepared CQ@PLGA@PDA NPs have good photothermal performance and high biological safety; by inhibiting autophagy, they can effectively kill tumor cells under mild photothermal conditions(< 50℃).

Protective effect of melatonin against lead-induced neurotoxicity in PC12 cells / 中华劳动卫生职业病杂志

Objective@#To study the protective effect of melatonin (MT) against lead-induced neurotoxicity.@*Methods@#PC12 cells were divided in four groups (control, 25 μmol/L PbAc, 50 μmol/L MT and 25 μmol/L PbAc+50 μmol/L MT) . After treatment, cell viability was detected by cell counting kit-8 (CCK-8) assay and cytotoxicity LDH assay were used to evaluate cell damage rate. The expression of Cleaved-Caspase-3 and cytochrome C (cyto C) was detected by immunofluorescence (IF) . ROS levels were measured by DCFH method. GSH contents and SOD activities were detected after whole cell protein was extracted.@*Results@#Compared with control group, 25 μmol/L PbAc caused significantly decreased cell viability, GSH contents and SOD activities, while increased cell damage rate and ROS level significantly (P<0.05) . 25 μmol/L PbAc could also increase the protein level of cleaved-caspase-3 and cyto C in cytoplasm. Compared with 25 μmol/L PbAc group, 50 μmol/L MT+25 μmol/L PbAc caused significantly increased cell viability, GSH contents and SOD activities, while decreased cell damage rate and ROS level significantly (P<0.05) . Compared with 25 μmol/L PbAc group, 50 μmol/L MT+25 μmol/L PbAc decreased the protein level of cleaved-caspase-3 and cyto C.@*Conclusion@#Melatonin could attenuate PbAc-induced oxidative stress and cell death and promote cell survival.

Initial practice on quality control tests and action limits setting of birdcage head coils / 中国医学影像技术

Objective To establish clinical quality control method with testing the birdcage head coils and setting up the action limits.Methods Three different MR devices (GE 1.5T HDi,GE 3.0T HD and GE 3.0T 750W) and corresponding birdcage coils were tested.Axial T1WI was performed to scan ACR phantom.SNR,percent image uniformity (PIU) and percent signal ghosting (PSG) were measured for six times,and the mean values and standard deviations (SD) were calculated.Based on the results,the action limits for each parameter were set.Results The mean value of SNR for the three devices was 262.14,280.47 and 474.24,and SD was 18.43,29.67 and 29.95,respectively;the action limits were ≥225.28,≥221.13 and ≥414.34,respectively;the mean value of PIU for the three devices was 95.00％,83.17％ and 84.33％,SD was 0.63％,1.17％ and 0.82％,respectively;the action limits were ≥93.74％,≥82.00％ (corrected) and ≥82.69％,respectively.The mean value of PSG for the three devices was 0.11％,0.07％ and 0.14％,SD was 0.12％,0.03％ and 0.11％,respectively;the action limits were ≤0.35％,≤0.13％ and ≤0.36％,respectively.Conclusion All of SNR,PIU and PSG for three MR devices were consistent with the action limits in this study.

Stability tests and action limits setting for central frequency and transmitter gain of MRI scanners / 中国医学影像技术

Objective To test the central frequency (CF) and transmitter gain(TG) of MRI scanners,and set up their action limits.Methods Three different MRI devices (GE 3.0T HD,GE 1.5T HDi and GE 3.0T 750W) were tested by scanning American College of Radiology (ACR) phantom with the axial T1WI series.In the pre-scanning of T1WI series for the ACR phantom,the CF and TG were recorded.It was tested for eight times when MRI scanners were in good condition.The action limits of CF and TG were calculated based on mean values and standard deviations.Results The mean values of CF for three devices were (127 725 772.38±39.68)Hz,(63 875 740.13± 34.15)Hz,and (127 771 958.38±12.19)Hz,respectively.Their action limits were ≤119.04 Hz,≤68.30 Hz,and ≤36.57 Hz,respectively.The mean values of TG for three devices were (125.25±1.28)dB,(101.75±1.98)dB,and (113.25±0.89)dB,respectively.Their action limits were (125.25±2.56)dB,(101.75±3.96)dB,and (113.25±1.78)dB,respectively.Conclusion The CF and TG for three MRI scanners are all consistent with the action limits in this study.The CF and TG action limits will provide criterions for the clinical quality control.

Status and tendency of clinical quality control procedure and regulation for MRI equipment / 中国医学影像技术

Clinical quality control of MRI equipment is a significant part of quality assurance.The purpose of quality control is to assure the performance and specification stability of MRI scanner,and to provide high quality images for clinical diagnosis.Many foreign countries have already developed and established highly sophisticated quality control procedure and regulation for MRI system,and the application is also relatively popular.However,this work has just begun in China,need to be further developed.The current status and future trend of clinical quality control procedure as well as regulation for MRI equipment were reviewed in this article.

Initial practice on cross-talk tests for MRI scanners / 中国医学影像技术

Objective To detect the cross-talk RF signal interference of three MRI scanners,in order to deepen the understanding of cross-talk RF signal interference.Methods Three different GE magnetic resonance imaging scanners (GE 1.5T HDi,installation time:2012;GE 3.0T HD,installation time:2006;GE 3.0T 750W,installation time:2016) were tested.The axial T1-weighted sequence was used to scan ACR phantom.Slice gaps with 5.0 mm,1.0 mm,0.5 mm and 0 were performed,respectively.SNR values were also recorded.Based on the results,the percentage change charts of SNR with slice gaps were made.Test standard was set as SNR decreased less than 20 ％ when the slice gap reduced from 5 mm to 0.Results When slice gap was reduced from 5 mm to 0,SNRs for three scanners decreased by 18.16 ％,23.57％ and 10.75％,respectively.Both the results of cross-talk obtained with GE 1.5T HDi and GE 3.0T 750W scanner met the test standard,while the result obtained with GE 3.0T HD (used for more than 10 years) was below the standard.Conclusion The cross-talk RF signal interference still exists for three MRI scanners.The test result of the scanner used for the longest time is unqualified.The quality control test of cross-talk should be done in the daily work.

Investigation and practice of magnetic field homogeneity evaluation methods for MRI equipment / 中国医学影像技术

Objective To explore the evaluation methods of magnetic field uniformity and the practical operations,in order to provide references for clinical quality control.Methods Based on MRS phantom and 32 cm uniform spherical phantom,the evaluation methods of magnetic field uniformity were used to detect MRI equipment in department of radiology,including spectral peak and the bandwidth difference.Results The full width at half maximum (FWHM) of MRS phantom was 0.08 ppm,the inhomogeneity values on coronal,sagittal and axial detected by the bandwidth difference method was 0.15 ppm,0.08 ppm and 0.18 ppm,respectively.Conclusion The magnetic field homogeneity of the above mentioned MRI equipment is favorable,which accords with magnetic field uniformity detection standard.

Association between PLA2G4C minisatellite polymorphism and schizophrenia / 吉林大学学报(医学版)

Objective To investigate the association between the minisatellite polymorphism in the first exon of PLA2G4C gene and schizophrenia, and to reveal the important role of DNA sequence polymorphism in the pathogenesis of schizophrenia.Methods The minisatellite polymorphisms in the first exon of PLA2G4C gene in 91 patients with schizophrenia (case group)and 81 healthy persons (control group)were detected with PCR-sequencing analysis.The chi-square (χ2 )goodness-of-fit test was used to analyze the distribution of the PLA2G4C minisatellite polymorphism in various groups and to explore the association between the minisatellite polymorphism in the first exon of PLA2G4C gene and schizophrenia. Results There were minisatellite polymorphisms in PLA2G4C gene.Three kinds of polymorphisms 1×27 bp,2×27 bp and 3×27 bp were found by sequencing.The distribution of allelic frequencies at PLA2G4C polymorphism showed no statistical significance between case group and control group (P>0.05 ). No statistically significant difference was found in 3-homozygous haplotypes in PLA2G4C gene between case group and control group (P>0.05).At the same time,there was no statistically significant difference between 3-heterozygous haplotypes in PLA2G4C gene between case group and control group (P>0.05).Conclusion The minisatellite polymorphisms in the first exon of PLA2G4C gene are found,but the minisatellite polymorphism in the first exon of PLA2G4C gene may be not associated with the occurrence of schizophrenia.

A novel peptides, like nerve growth factor, inducing pheochromocytoma PC12 cell differentiation / 吉林大学学报(医学版)

Objective: To isolate the key domain of a novel polypeptide fragment from NGN-β that functions like intact NGF molecule.Methods: NGF-β had been treated with cyanogen bromide and trypsin skillfully. The peptide fragment with the activity inducing PC12 pheochromocytoma cells differentiation was isolated and purified by Sephadex G-50 gel filtration chromatography , DE-52 celluloseion exchange chromatography and C-18 reversed-phase column HPLC after NGF-β cleavaged by CNBr at 9th met then by trypsin at Arg or Lyscleavaged by CNBr at 9th met then by trypsin at Arg or Lys. Amino acid sequencing of this novel peptide fragment was performed by Automatic Amino Acid Analyser and Amino Acid Sequencer. Results: The functional fragment from cleavaged NGF might induce differentiation of PC12 cells. The fragment was consisting of two linear polypeptides . One of them was 16 peptide, GEFSVCDSVSVWVGDK , and other was 14 peptide, HWNSYCTTTHTFVK, linked by a disulphide bridge corresponding to residues 10～25 and 75～88, respectively, of the amino acid sequence of nerve growth factor, the result of biological activity assay in PC12 cells showed that the optimum concentration of this peptide were 0.001～0.1 μg*L-1. Conclusion: A novel peptide inducing differentiation of PC12 cell line of pheochromocytoma cells was obtained in the study. It′s isolation and purification successfully will underlie synthesis or expression of hyperactive neurotrophic small molecular substance although the relationship between the configuration and functions is not clearly.