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Objective:To explore the effects of laser irradiation parameters (irradiation frequency and single duration) on tear secretion, lens and retina.Methods:Thirty-six healthy guinea pigs were randomly divided into 6 groups with random number table method according to different frequency and single exposure duration of laser to the eye, namely, high frequency short time (HFST) group, high frequency long time (HFLT) group, medium frequency short time (MFST) group, medium frequency long time (MFLT) group, low frequency short time (LFST) group and low frequency long time (LFLT) group, 6 for each group.The right eyes were irradiated with 500 lx laser as experimental eyes, and the left eyes of the guinea pigs served as the control eyes.The high, medium and low irradiation frequencies were defined as 15 times, 10 times and 5 times, respectively, and the short and long period was defined as 30 seconds and 60 seconds each time, respectively.The right eyes were irradiated based on the grouping at a 10-minute interval.The tear secretion was detected by SchirmerⅠtest; lens opacity was assessed under the slit-lamp microscope; fundus photography was performed to evaluate the general morphology of retina; retinal function was evaluated by electroretinogram (ERG) record and the thickness of retinal outer nuclear layer was measured by histopathology examination.This study protocol was approved by the Medical Ethics Committee of Air Force Military Medical University (No.20181203), and the use and care of the experimental animals complied with the ARVO statement.Results:The tear secretion was 8.00(7.37, 9.00), 8.75(8.25, 9.00), 8.50(7.75, 9.50), 9.00(8.50, 9.50), 8.00(7.37, 8.75) and 8.25(7.75, 8.75) mm/5 min in the HFST group, HFLT group, MFST group, MFLT group, LFST group and LFLT group, respectively, without significant difference among the groups(χ 2=5.502, P=0.240); after laser irradiation, there were no statistically significant differences in tear secretion between the control eyes and laser-irradiated eyes in all the groups (all at P>0.05). The lenses were clear and the fundus was normal through the experimental duration in all the groups.The amplitude of ERG a-wave was significantly reduced in the HFST group in comparison with the LFST group (P<0.05), and there was no significant difference in the b-wave amplitude among the six groups (F=1.358, P=0.268). The ERG a-, b-wave amplitudes were not significantly different between the control eyes and laser-irradiated eyes in various groups (both at P>0.05). There was no significant difference in the thickness of the outer nuclear layer of retina among the HFST group, HFLT group, MFST group, MFLT group, LFST group and LFLT group (F=0.952, P=0.463). Conclusions:The 500 lx laser irradiation is safe to ocular surface and lens, but there are some injuries to retinal function, and the injury degree is related to laser irradiation frequency.
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Objective@#To investigate the current status of professional identity among the undergraduates majoring in public affairs management and the related influence factors.@*Methods@#A stratified cluster sampling method was used to conduct a questionnaire survey among the 115 undergraduates majoring in public affairs management in a medical university in Harbin, China, and the contents of the questionnaires included general status and professional identity. The t-test, one-way analysis of variance, and multiple linear regression analysis were used to analyze the influencing factors of professional identity. In-depth interviews were conducted for some students to explore the profound influencing factors for professional identity among the students majoring in public affairs management.@*Results@#The overall level of professional identity was low among the undergraduates majoring in public affairs management in the medical university in Harbin, and the score of professional identity was 3.25±0.56. The scores of cognitive dimension, emotional dimension, behavioral dimension, and applicable dimension were 3.41±0.69, 3.21±0.78, 3.24±0.71, and 3.13±0.72, respectively. The multivariate analysis showed that grade, academic performance, major selection, and children number in family had significant influence on their professional identity. The students who were at grade four, who had high academic record (b=-0.276, P<0.01), who chose this major independently (b=-0.277, P<0.01), and who were the only child (b=-0.233, P<0.05) had a high score of professional identity. As for the undergraduates at different grades, the undergraduates at grades two and three had a significantly lower score of professional identity than those at grade four (b=-0.296 and -0.369, P<0.05), while there was no significant difference between the undergraduates at grades one and four (b=-0.008, P>0.05). Furthermore, the students with a high score of professional identity had higher possibility to pursue the job related to this major than those with a low score (3.39±0.53 vs. 2.92±0.49, t=4.414, P<0.01).@*Conclusion@#Universities should strengthen the publicity of the major of public affairs management, optimize the curriculum, and add job experience, so as to enhance professional identity among students with this major and provide talent for the field of public health management.
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Objective To investigate the current status of professional identity among the undergraduates majoring in public affairs management and the related influence factors.Methods A stratified cluster sampling method was used to conduct a questionnaire survey among the 115 undergraduates majoring in public affairs management in a medical university in Harbin,China,and the contents of the questionnaires included general status and professional identity.The t-test,one-way analysis of variance,and multiple linear regression analysis were used to analyze the influencing factors of professional identity.In-depth interviews were conducted for some students to explore the profound influencing factors for professional identity among the students majoring in public affairs management.Results The overall level of professional identity was low among the undergraduates majoring in public affairs management in the medical university in Harbin,and the score of professional identity was 3.25 ± 0.56.The scores of cognitive dimension,emotional dimension,behavioral dimension,and applicable dimension were 3.41 ± 0.69,3.21 ± 0.78,3.24 ± 0.71,and 3.13 ± 0.72,respectively.The multivariate analysis showed that grade,academic performance,major selection,and children number in family had significant influence on their professional identity.The students who were at grade four,who had high academic record (b =-0.276,P＜ 0.01),who chose this major independently (b=-0.277,P＜0.01),and who were the only child (b=-0.233,P＜ 0.05) had a high score of professional identity.As for the undergraduates at different grades,the undergraduates at grades two and three had a significantly lower score of professional identity than those at grade four (b=-0.296 and-0.369,P＜0.05),while there was no significant difference between the undergraduates at grades one and four (b=-0.008,P＞0.05).Furthermore,the students with a high score of professional identity had higher possibility to pursue the job related to this major than those with a low score (3.39 ± 0.53 vs.2.92 ± 0.49,t=4.414,P＜0.01).Conclusion Universities should strengthen the publicity of the major of public affairs management,optimize the curriculum,and add job experience,so as to enhance professional identity among students with this major and provide talent for the field of public health management.
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Objective To investigate the mediating effects of neurotic personality between parental rearing patterns and depressive symptom.Methods Using multistage sampling method,982 town middle-school students were surveyed by the Symptom Checklist 90(SCL-90),the Egna Minnen av Barndoms Uppfostran (EMBU),the Eysenck Personality Questionnaire (EPQ).Correlation and regression analysis,mediating effect test,and structural equation model were constructed.Results ①)Depressive symptom (D) (1.73 ± 0.72) was significantly associated with Neurotic personality (N) (51.50± 11.37) and parental rearing patterns (r=-0.138-0.582,P＜0.01).②N,mother's rejection and deny(M3),father's emotional warmth and understanding(F1),father's over-protection(F6) had a direct effect on D,which can explain 41.6％ of the variance.F1,F6,mother's over-interference and over-protection(M2),M3 had a direct effect on N,which can explain 15.3％ of the variance.The mediating effect of N between F1,F6,M2 and D were significant(95％CI =-0.212--0.069,-0.351--0.233,0.414-0.480).③The explanation for D was 41.3％.N had completely mediating effect between M2 and depressive symptom.N had partial mediating effect between F1,F6 and D,and the proportion was 43.6％ and 49.1％.Conclusion Neurotic personality plays a mediating role between parental rearing patterns and depressive symptom in middle-school students.
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Objective To establish a central serous chorioretinopathy (CSC) model on different strains of rabbits by intravenous injection of adrenaline,which may contribute to related researches of CSC.Methods This study was approved by Bioethics Committee of Fourth Military University and complied with Statement for the Use of Animals in Ophthalmic and Visual Research.Fundus fluorescein angiography (FFA) was initially performed on male New Zealand white rabbits (10),Belgium rabbits (5) and Chinchilla rabbits (10) to make sure that the retinas of subjects were normal.For the New Zealand white rabbits,adrenaline was injected via ear vein at a dose of 0.04 mg/kg once per day for the first 8 weeks and followed by a dose of 0.08 mg/kg for the next 4 weeks,while 0.04 mg/kg adrenaline was injected in the same way for 8 weeks in the Belgium rabbits and Chinchilla rabbits.FFA was performed every week after injection of adrenaline to evaluate the fluorescence leakage in ocular fundus.New Zealand white rabbits were sacrificed in 4 (3 rabbits),8 (3 rabbits) and 12 weeks (4 rabbits) after injection respectively,and Belgium rabbits and Chinchilla rabbits were sacrificed in the 8 weeks after injection.The eyeballs of the rabbits were enucleated to prepare the retinal sections for histopathological examination after hematoxylin-eosin staining.The results of FFA and retinal structure were compared among different strains of rabbits.Results No fluorescence leakage was found by FFA in ocular fundus,and the retinal structure was normal in all the 10 New Zealand white rabbits during the experiment.Fluorescence leakage was found by FFA in 2 Belgium rabbits at 1 week and 2 weeks after injection respectively,and retinal detachment and depigmentation of retinal pigment epithelium (RPE) with an enlarged intercellular space were shown by hematoxylin-eosin staining.For the Chinchilla rabbits,fluorescence leakages were found in 7 rabbits throughout the whole period of adrenaline administration.Circumscribed retinal detachment,depigmentation of RPE with enlarged intercellular space were also found in leakage lesions.Conclusions Repeated intravenous injection of adrenaline can induce CSC-like lesions in colored rabbits but not in albino rabbits.
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Background Congenital stationary night blindness (CSNB) is a common genetic eye disease.Retinal angiogenesis is rarely obtained in retinal degeneration animal.The effects of CSNB on retinal angiogenesis require further study.Objective This study was to improve Chinese ink perfusion technology and to explore the effect of CSNB on oxygen induced neovascularization.Methods Eighteen clean 7-day old SD rats and 18 clean 7-day old CSNB rats were included,twelve SD rats and twelve CSNB rats were chosen randomly for oxygen induced retinopathy (OIR) modeling,and served as OIR group,six SD rats and six CSNB rats were chosen as normal control.Nine rats were chosen randomly from both SD rats and CSNB rats in OIR group,respectively.The rats were separated into 1 ∶ 1 ratio ink group,2 ∶ 1 ratio ink group and conventional ink group,which were perfused with 1 ∶ 1 ratio ink perfusate,2 ∶ 1 ratio ink perfusate and conventional ink,respectively.The unilateral eyes of the rats were prepared for whole-mount retina,the other eyes were performed for paraffin imbedding.The quality of retinal vascular imaging were compared among different ink perfusate groups.The normal control rats,three SD rats in OIR group and three CSNB rats in OIR group were perfused with 2 ∶ 1 ratio ink perfusate.Histopathology examination was performed on the paraffin section,and the number of nuclei breakthrough the inner limiting membrane were counted.Immunocytochemistry were performed on the paraffin section for detecting the expression of von Wilebrand factor (vWF).Results Compared with 1 ∶ 1 ratio ink perfusion and conventional ink perfusion,2 ∶ 1 ratio ink perfusion showed the full vascular net clearly.Histopathology showed that the structure of retina was normal in the normal control group,and there were no endothelial nuclei breakthrough the inner limiting membrane.A large number of endothelial nuclei breakthrough the inner limiting membrane in the OIR group,the number of endothelial nuclei breaking through the inner limiting membrane were (23.08±2.99)/slide and (41.12±9.36)/slide for SD rats and CSNB rats,respectively.The number of endothelial nuclei breakthrough inner limiting membrane was higher in the CSNB rats than that in the SD rats,with no difference between the two group (q =1.70,P =0.50).Immunocytochemistry results showed that v-WF was positive expressed in the cells breakthrough inner limiting membrane.Conclusions Improved ink perfusion method was an easy-to-use whole-mount retina method with good repeatability.Hyperoxia can induce retinal neovascularization of CSNB rats.
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Background Optic nerve crush (ONC) model is an available tool in the basic research on the mechanism and treatment of optic nerve injury.The opening optic nerves sheath crushing and via bulbar conjunctiva lateral canthus optic nerves crushing are frequently used ONC modeling methods.However,the comparison between these models is not elaborated.Objective This study was to compare the outcomes between opening sheath ONC model and via bulbar conjunctiva lateral canthus ONC model.Methods Twenty-four male SD rats were randomized into four groups.ONC models were established via superorbital rim opening sheath to crushing optic nerve for 20 seconds in the opening sheath ONC group,or via bulbar conjunctiva lateral canthus cutting to crush optic nerve for different time in the via bulbar conjunctiva ONC 20-second,40-second and 60-second groups,respectively.All models were monocular created in the rats,and the fellow eyes served as controls.In 14 days after modeling,flash visual evoked potential (F-VEP) were recorded,optic nerve and retinal sections were prepared in the rats.The histopathology of the samples was examined by hematoxylin and eosin staining.The expression of Brn-3α in the retinal ganglion cells (RGCs) was detected by immunofluorescence technique and the number of Brn-3α+ RGCs was counted.The modeling procedure and outcomes were compared between the two approaches.Results The latencies of P1 waves were significantly extended in the opening sheath ONC group,via bulbar conjunctiva ONC 20-second,40-second and 60-second groups in comparison with the corresponding control eyes (t =-11.64,-8.04,-6.50,-10.84,all at P＜0.01).The P1 latencies were longer in the opening sheath ONC group than those in the via bulbar conjunctiva ONC 20-second,40-second and 60-second groups (P =0.01,0.02,0.05),but no significant differences were found in the amplitudes of P1 waves between model eyes and corresponding control eyes (all at P＞0.05).The Brn-3α+ RGCs numbers were evidently decreased in the model eyes in comparison with the fellow control eyes.The Brn-3 α + RGCs numbers were (13.60 ± 2.14),(18.74 ± 3.61),(15.84 ± 2.31) and (14.58 ± 3.23)/field in the opening sheath ONC group,via bulbar conjunctiva ONC 20-second,40-second and 60-second groups,which reduced to 47.49％,67.70％,56.69％ and 50.17％ of the fellow eyes,respectively.No significant differences were seen in the Brn-3α+ RGC numbers between the opening sheath ONC group and via bulbar conjunctiva ONC 40-second or 60-second groups (both at P＞0.05).The disorder of glial cell arrangement,vacuolization of the cell matrix and infiltration of inflammatory cells were displayed in various model groups,with the prominent findings in the opening sheath ONC group.Conclusions Compared with the via bulbar conjunctiva ONC models,the morphological and functional damage of optic nerve is more obvious,and the survival rate of RGCs is lower in the opening sheath ONC models.
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Objective To explore the tobacco control project based health education curriculum reform's effect of improving medical students' tobacco control.Method Choosing the students of two classes of students in preventive medicine specialty of Harbin Medical University as the research object, investigating the students respectively with the questionnaire prepared uniformly by 7 schools before and after the course.All data were coded by Epidata 3.0, and SPSS 18.0 was used to carry out the relevant information for the chi square test and t test.Result The sample size of baseline survey was114 and after the intervention was 87.The knowledge pass rate of the girls before and after the intervention were 87.3％ (48/55) and 98.2％ (54/55) respectively (P=0.000).The boys' awareness rate of the secondhand smoke safety level were 13.6％ (8/59) and 21.9％ (7/32) respectively, and the girls were 13.0％ (7/55) and 31.5％ (17/55) (P=0.021).Students interested in tobacco increased from 79.8％ (91/114) before intervention to 90.8％ (79/87) after intervention (P=0.033).Students willing to work in the tobacco related increased from 52.2％(59/114) before intervention to 66.7％ (58/87)after intervention (P=0.044).The girl who replied after intervention I am not smoking now, but won't smoke either when working in the disease control in the future reached as high as 96.4％ (53/55), but the students were lack of confidence to help people to stop smoking.Conclusion The reform of social practice activity curriculum designed for tobacco control project is effective, and it is urgent to strengthen the training of preventive medical students' smoking cessation skills and enhance their confidence.
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Objective To compare the impact of tobacco control curriculum on self-efficacy of tobacco control in different major of public health students, and offer theoretical foundation for improving tobacco control curriculum.Methods We offered tobacco control curriculum for 150 public health students (including students of preventive medicine and public service administration research direction) in medical university of Harbin, and investigated twice general self-efficacy, smoking selfefficacy and tobacco control self-efficacy before and after tobacco control curriculum, then compared intervention effects between two major students by t test.Results There were no differences of tobacco control self-efficacy, smoking self-efficacy and general self-efficacy between two major students, t values were-0.832 (P=0.407), 0.190 (P=0.849) and-0.492 (P=0.624).The tobacco control self-efficacy (t=-3.566, P=0.001) and general self-efficacy (t=-2.237, P=0.028) increased remarkably but smoking self-efficacy (t=-1.102, P=0.273) in preventive medicine students after intervention.And all of three kinds of self-efficacy were not gotten better by intervention in public service administration students.There was no obvious difference of intervention effects between tobacco control self-efficacy and general self-efficacy among preventive medicine students (t=1.541, P=0.125).Conclusions The improvement of preventive medicine students by tobacco control curriculum is better than that of public service administration students.We should further perfect the tobacco control course, and on the one hand, improve the intervention effect of students majoring in course of public health management;on the other hand, strengthen the target effects of the tobacco control curriculum to students' tobacco control self-efficacy and smoking self-efficacy.
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With characteristics of the subject, teaching objectives, teaching contents, teaching methods and the examination form as the basic principle, electroencephalogram curriculum teaching of clinical aerospace medicine was adjusted. Starting from the teaching preparation stage, focusing on the important teaching points and making multimedia courseware carefully, one typical case was designed as the opening of the class, which led to the teaching content; the use of multimedia teaching means making theories of electroencephalogram comprehensible; case discussion was set in class to test teaching effects;once finding problems, they were rectified timely, and teaching experiences were also summarized at the end of the class. Thus, the teaching mode of student participation with teacher-student interaction was established, and the importance of training the student's ability to use knowl-edge flexibly to solve practical problems in their future jobs was manifested in the implementation process of teaching.
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The inherent evolvability of promiscuous enzymes endows them with great potential to be artificially evolved for novel functions. Previously, we succeeded in transforming a promiscuous acylaminoacyl peptidase (apAAP) from the hyperthermophilic archaeon Aeropyrum pernix K1 into a specific carboxylesterase by making a single mutation. In order to fulfill the urgent requirement of thermostable lipolytic enzymes, in this paper we describe how the substrate preference of apAAP can be further changed from p-nitrophenyl caprylate (pNP-C8) to p-nitrophenyl laurate (pNP-C12) by protein and solvent engineering. After one round of directed evolution and subsequent saturation mutagenesis at selected residues in the active site, three variants with enhanced activity towards pNP-C12 were identified. Additionally, a combined mutant W474V/F488G/R526V/T560W was generated, which had the highest catalytic efficiency (k (cat)/K (m)) for pNP-C12, about 71-fold higher than the wild type. Its activity was further increased by solvent engineering, resulting in an activity enhancement of 280-fold compared with the wild type in the presence of 30% DMSO. The structural basis for the improved activity was studied by substrate docking and molecular dynamics simulation. It was revealed that W474V and F488G mutations caused a significant change in the geometry of the active center, which may facilitate binding and subsequent hydrolysis of bulky substrates. In conclusion, the combination of protein and solvent engineering may be an effective approach to improve the activities of promiscuous enzymes and could be used to create naturally rare hyperthermophilic enzymes.
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Aeropyrum , Química , Proteínas Arqueais , Genética , Metabolismo , Sítios de Ligação , Biocatálise , Caprilatos , Metabolismo , Clonagem Molecular , Dimetil Sulfóxido , Química , Escherichia coli , Temperatura Alta , Microbiologia Industrial , Métodos , Cinética , Lauratos , Metabolismo , Simulação de Dinâmica Molecular , Mutagênese Sítio-Dirigida , Métodos , Peptídeo Hidrolases , Genética , Metabolismo , Ligação Proteica , Conformação Proteica , Proteínas Recombinantes , Genética , Metabolismo , Solventes , Química , Especificidade por SubstratoRESUMO
BACKGROUND: The permeability of blood-retinal barrier in rats can be increased due to the exposure under infrasound. There is rare research on ionic mechanism of such damage to barrier because of lacking the sources of retinal microvascular endothelial cells.OBJECTIVE: To investigate the impact of infrasound on calcium-activated potassium channel(BKca) of bovine retinal microvascular endothelial cells (BRECs).DESIGN: A completely randomized controlled opening study.SETTING and MATERIALS: The research was conducted in the Laboratory for patch-clamp, Department of Clinical Aerospace Medicine, Fourth Military Medical University of Chinese PLA. Experimental subjects were BRECs cultured.INTERVENTIONS: The cultured BRECs were exposed to the infrasound of 8 Hz, 130 dB for 30 minutes.MAIN OUTCOME MEASURES: The activity of BKCa in BRECs was observed.RESULTS: The activity of BKCa channel in BRECs increased after the exposure of infrasound of 8 Hz, 130 dB for 30 minutes. BRECs were cultured in an incubation cabin for 30 minutes after exposure for another detection by patch-clamp ionic current, and the increased BKCa channel activity slightly decresed.CONCLUSION: The breakdown of blood-retinal barrier under infrasound is partly due to the stimulatory effect of infrasound on Ca2 +-activated-K +channel, which will cause membranous depolarization providing the driving force of Ca2+ influx on BRECs.