Pre-graduation practice is an important part of teaching work for preventive medical science.The article is about investigation on the pre-graduation practice of 85 preventive medical students just graduated,and some suggestions for improvement.It is found that the overall teaching effect is good,but there are some problems,mainly on the construction of practice base,practice contents and time,and also graduation design.

The purpose of this study is to show the basic principle of receiver operating characteristic (ROC). Some advantages of ROC were given. A simple ROC curve was made to explain the method of plotting. An example of ROC applied to fMRI data was displayed, which showed that ROC can be effectively used in fMRI data.
Brain ; physiology ; Humans ; Magnetic Resonance Imaging ; ROC Curve ; Signal Processing, Computer-Assisted

BACKGROUND: The rudiment of tissue engineering is to obtain tissue from patients. The cells are expanded into a population through cellular culture, and seeded into scaffolds, which can accommodate and guide the growth and proliferation of new cells in the three-dimensional scaffolds. At last, the constructed tissue is transplanted in vivo to repair or replace damaged or diseased tissues. Afterward neovascularization of the graft, the scaffolds are absorbed gradually. Finally, the new tissue replaces completely the damaged or diseased tissuesOBJECTIVE: To evaluate the feasibility of designing and fabricating customized anatomical-shaped bone tissue-engineering scaffolds with reverse engineering and rapid prototyping (RP) techniques. To avoid the disadvantage of the conventional fabricated methods of the scaffolds.DESIGN: The method of fabricating customized anatomical-shaped bone tissue engineering scaffolds.SETTING: Computer-aided design (CAD) of the scaffold was conducted in CAD training center, Guangdong Machinery Research Institute. Rapid prototyping fabrication of the scaffold was conducted in Guangdong Longchuangyu Limited Cooperation. The scaffold was fabricated by sterophotocureable technology and was made of photosensitized resin.METHODS: This experiment was carried out at the Center of Department of Traumatic Orthopedics, General Hospital of Guangzhou Military Area Command of Chinese PLA from October 2004 and January 2005. According to reverse engineering, layered image information of skeleton of the patients was scanned with CT/MRI. Anatomical models of region of interesting were created by means of CT or MRI three-dimensional reconstruction and surface reconstruction. The internal construction of the scaffolds was designed with CAD software in the outline of the anatomical models to develop computer-aided model. The prototypes of the scaffolds were fabricated by RP process.MAIN OUTCOME MEASURES: ①CT/MRI scanning, three-dimensional reconstruction, anatomical modeling; ② computer-aided design of customized bone tissue engineering scaffolds; ③rapid prototyping fabrication of customized bone tissue engineering scaffold.RESULTS: ①Anatomical models of bone joint were established through CT/MRI three-dimensional reconstruction. ② The internal structure of the scaffold was designed to establish the entity model of bone tissue engineering scaffold successfully with computer-aided design software. ③ CAD model of bone tissue engineering scaffold guided prototypes to develop the customized anatomical-shaped bone tissue engineering scaffolds. The internal structure of bone tissue engineering scaffold was fine and had high degree of porosity-and pore interconnectivity.CONCLUSION: Customized anatomical-shaped bone tissue engineering scaffolds can be fabricated with reverse engineering and RP technology. Among all RP processes, stereophotocureable technology (SLA) is the best one with good precision, smooth surface and good shaping.

The application of independent component analysis (ICA) to the functional magnetic resonance imaging (fMRI) data can separate many independent sources. But in the processing there are two difficulties: (1) the data of the fMRI is usually on a large scale, so the computing is time-consuming; (2) we cannot avoid the errors for too heavy computational load, this brings many troubles. Thus we think of reducing the data. In this article we used the standard information theoretic methods to estimate the number of the sources and used the principal component analysis (PCA) to reduce the data. By this process, we estimated the number of the sources and reduced the data successfully; Then we applied the ICA algorithm to the reduced fMRI data; this method raised the speed of operation. After application of the new ICA algorithm and another algorithm (FastICA) to the fMRI data, a comparison was made. The results show that the new algorithm can separate the fMRI data fast and effectively and it is superior to the FastICA on the accuracy of estimating the temporal dynamics of activations.
Algorithms ; Humans ; Image Processing, Computer-Assisted ; Magnetic Resonance Imaging ; methods ; statistics & numerical data ; Male ; Principal Component Analysis ; Signal Processing, Computer-Assisted ; Software ; Young Adult

Cytochrome P450 enzyme 1A1 (CYP 1A1) is one of the main members of CYP1A subfamily, which participates in metabolizing and activating a variety of indirect carcinogens. CYP1A1 can induce carcinogenesis by participating in activating exogenous compounds to produce intermediates or active metabolites that bind to specific biomolecules. CYP1A1 plays a critical role in the metabolic activation of benzo(a)pyrene e ［B(a)P］, and plays a key role in activating the toxic and carcinogenic effects of B(a)P. CYP1A1 involves in the metabolic activation of 7,12-dimethyl benzanthracene and 2-amino-1-methyl-6-phenylimidazo［4,5-b］pyridine (PhIP), and plays an important role in PhIP-induced genotoxicity. CYP1A1 is the main enzyme to metabolize and activate 7H-dibenzo［c,g］carbazole (DBC), a key factor in the carcinogenic effect of DBC. CYP1A1 is also associated with metabolic activation of indirect carcinogens such as aflatoxin B1, 3-nitrobenzene, and naphthalene. Inhibition of the catalytic activity of CYP1A1 can decrease the CYP1A1-mediated activity of carcinogens, thus playing a role in the prevention and treatment of malignant tumors.

OBJECTIVETo investigate the role of sphingosine kinase 1 (SphK1) in regulating the proliferation of hypoxia-exposed glioma cells in vitro and explore the possible molecular mechanisms.

METHODSHuman glioblastoma U87MG cells was transfected with specific small interfering RNA (siRNA) constructs targeting SphK1, and the efficiency of SphK1 knockdown was validated by real-time PCR and Western blotting. The cells transfected with SphK1 siRNA and with a negative control siRNA were then exposed to 3% oxygen or 150 µmol/L CoCl2 to induce hypoxia. The cell proliferation and cell cycle changes following the exposure were evaluated with the Cell Counting Kit-8 and flow cytometry, respectively, and the intracellular Ca(2+) changes were monitored using Flou-4/AM under an inverted laser scanning confocal microscope.

RESULTSSphK1 knockdown significantly reduced hypoxia-induced calcium reflux and suppressed the cell proliferation. Application of OAG, an activator of calcium channels, however, obviously enhanced the cell proliferation under hypoxia.

CONCLUSIONSphK1 promotes the proliferation of glioma cells under hypoxia via regulating calcium signaling.

Calcium Signaling ; Cell Cycle ; Cell Hypoxia ; Cell Line, Tumor ; Cell Proliferation ; Glioblastoma ; Glioma ; pathology ; Humans ; Phosphotransferases (Alcohol Group Acceptor) ; metabolism ; RNA, Small Interfering

Objective To investigate the prevalence and influencing factors of sub-health status of the migrant workers in Dongguan City,in order to provide scientific preferences for preventing sub-health status.Methods Using the stratified random sampling method,740 migrant workers from ten towns(disetricts) in Dongguan city from August 2015 to August 2016 were recruited in this study.The sub-health measurement scale version 1.0 (SHMS V1.0) was applied to evaluate the sub-health status of migrant workers.The SHMS V1.0 scores were compared among migrant workers with different demographic characteristics,and the multivariate linear regression analysis was utilized to explore the influencing factors.Results A total of 718 valid questionnaires were collected,and the effective recovery rate was 97.03％.The sub-health status was detected in 483 migrant workers,and the prevalence rate of sub-health status was 81.6％.The migrant workers' subscale scores of physical sub-health (PS),mental subhealth (MS),social sub-health (SS) and total scale (TS) were (70.25-4-12.25),(64.21± 13.83),(62.21-4-13.87) and (66.114-11.15),respectively.The PS scale scores among migrant workers with different monthly household incomes per capita,and different inhabit situations;the MS scale scores among migrant workers with different ages,educations,marital status,monthly household incomes per capita,and inhabit situations;the SS scale scores among migrant workers with different genders,educations,and inhabit situations;and TS scores mong migrant workers with different educations,monthly household incomes per capita,and inhabit situations were statistically significant different (P＜0.05).The multivariate linear regression analysis showed that educations and inhabit situations were the influencing factors for TS score (P＜0.05).Conclusion The sub-health status of migrant workers in Dongguan City is serious,and the influencing factors are educations and inhabit situations.

Using novel virtual reality (VR) technology to carry out the construction of clinical medical examination question bank, while deepening the reform of clinical medical course examination, it continues to innovate the medical professional evaluation system and improve the flexibility, diversity and scientificity of clinical medicine in teaching and assessment. It is of great and far-reaching significance to improve the teaching level and the quality of medical education in medical colleges and universities. This paper analyzes and discusses the necessity and feasibility of building a clinical medical examination question bank, and the advantages and prospects of integrating VR technology to carry out the construction of clinical medical examination question bank. At the same time, the exploration and practice of the examination question bank construction based on VR technology disscussed in detail would provide innovative thinking and reference for the clinical medical teaching and evaluation, medical personnel training and other aspects in China.

Objective:By detecting the level changes of CXC chemokine ligand 8(CXCL8)in acute myelogenous leukemia(AML)patients at different disease stages,to analyze its correlation with the clinical condition and prognosis of AML patients,and to explore the effect of CXCL8 in the bone marrow microenvironment on the occurrence and development of AML and the regulatory mech-anism of malignant biological behavior of AML cell lines,to provide novel reference for the basic research and clinical diagnosis and treatment of AML.Methods:Bone marrow specimens from AML patients at different disease stages were collected,and ELISA was used to detect the content of CXCL8;quantitative real-time PCR(qRT-PCR)was used to detect the expression of CXCL8-specific receptor CXCR1/2 in different AML cell lines.U937 cells were selected as the AML disease model,and different concentrations of exogenous rCXCL8 were intervened in U937 cells,and the morphological changes of the cells were observed under the microscope.BM-MSCs from newly diagnosed AML patients were co-cultured with U937 cells,and ELISA was used to detect the difference in the content of CXCL8 in the co-culture system;Annexin V/PI double staining flow cytometry was used to detect the effects of rCXCL8 and anti-CXCL8 on the apoptosis of U937 cells respectively,and Western blot was used to reveal the accompanying molecular protein mechanism.Results:The level of CXCL8 in newly diagnosed and relapsed AML patients was significantly higher than that in healthy people(P<0.05),the level of CXCL8 in relapsed stage of AML was significantly higher than that in other disease stages of AML(P<0.01),and the level of CXCL8 in AML patients with CR stage and no infection was significantly higher than that in healthy people(P>0.05).The content of CXCL8 in the co-culture system of BM-MSC and U937 cells and the level of CXCL8 mRNA in U937 cells in the co-culture system were significantly higher than those in the monoculture group without BM-MSC(P<0.05).Intervention of rCXCL8 in U937 cells could promote cell proliferation by up-regulating Bcl-2 expression and down-regulating Bax expression,and up-regulate the expression of CXCL8-specific receptors CXCR1/2.After antagonizing CXCL8(anti-CXCL8),it will induce U937 cell apoptosis by up-regulating of Bax expression and down-regulating of Bcl-2 expression while inhibiting the activation level of ERK1/2 signaling pathway.Conclusion:CXCL8 is closely related to the disease and prognosis of AML,and is an effective monitoring indicator for disease pro-gression and prognosis evaluation of AML patients.CXCL8 in the bone marrow microenvironment is an important chemokine for malig-nant proliferation and immune escape of leukemia cells.By antagonizing CXCL8,U937 cells can be induced to undergo apoptosis,whose mechanism may be related to the expression changes of Bcl-2 family proteins and the inhibition of ERK1/2 signaling pathway activation.

Objective:To investigate the expression level of small nucleolar RNA SNORD15A in bone marrow of patients with acute leukemia (AL) and its relationship with clinical characteristics and prognosis of patients.Methods:Bone marrow blood samples of 53 newly treated AL patients and 29 healthy subjects without clinical diagnosis of hematologic diseases or other malignant diseases (control group) at the Affiliated Hospital of Guangdong Medical University from March 2018 to December 2021 were collected. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the relative expression of SNORD15A in bone marrow blood mononuclear cells of the two groups. The median relative expression of SNORD15A (0.148) was used as the boundary, and AL patients were divided into low expression group (<0.148) and high expression group (≥0.148). The relationship between the expression level of SNORD15A and the clinical characteristics, clinical indicators and overall survival (OS) of AL patients was analyzed. Kaplan-Meier method was used for survival analysis and log-rank test was performed; Cox proportional hazards model was used for univariate and multivariate analyses of OS of patients.Results:The relative expression of SNORD15A was 0.148 (0.012-1.376) in newly treated AL patients and 0.921 (0.513-2.288) in the control group, and the difference was statistically significant ( Z = -6.85, P < 0.01). The differences in SNORD15A relative expression between patients with different prognostic stratification, efficacy and with or without fever and bleeding were statistically significant (all P < 0.05). The differences in platelet count, plateletcrit and albumin levels between SNORD15A low expression group and high expression group were statistically significant (all P < 0.05), and the differences in molecular biology and cytogenetic characteristics were not statistically significant (all P > 0.05). The patients in SNORD15A high expression group had better OS than the low expression group ( P < 0.05). The results of univariate Cox regression analysis showed that SNORD15A was an influencing factor for patients' OS ( HR = 0.063, 95% CI 0.005-0.766, P < 0.05); the results of multivariate Cox regression analysis showed that fatigue ( HR = 4.754, 95% CI 1.014-22.290), fever ( HR = 0.147, 95% CI 0.029-0.746) and hemoglobin ( HR = 0.970, 95% CI 0.944 -0.998) were independent influencing factors for OS (all P < 0.05). Conclusions:SNORD15A is lowly expressed in AL and may be an indicator for disease monitoring and prognostic assessment in AL patients.