Objective:To investigate the current situation of junior medical students'cognition on the relationship between doctors and patients,and to provide reference for medical students'medical education and medical education reform,Methods:Self-made questionnaire was adopted to investigate the cognitive status of doctor-patient relationship among junior medical students from three medical universities in Guangzhou.Results:Totally 41.04％ of junior medical students had a basic understanding of doctor-patient relationship,and the degree of understanding of doctor-patient relationship is not different between junior and senior medical students (P ＞ 0.05);76.62％ of medical students got acquainted with the status of doctor-patient relationship mainly through the media;86.57％ of junior medical students thought that the doctor-patient relationship was tense.The cognition of doctor-patient relationship between male and female students was similar (P ＞ 0.05),and so wasit between freshmen and sophomores (P ＞ 0.05).Male and female students had the same opinion on the future trend of doctor-patient relationship (P ＞ 0.05).Many junior medical students were optimistic about the future doctor-patient relationship.Compared with freshmen,sophomore medical students were less optimistic about the future doctor-patient relationship (P ＜ 0.05).Medical students mostly agreed on the causes of medical disputes (P ＞ 0.05),believing that the main reason was the medical system.Conclusions:The cognition of the doctor-patient relationship profoundly affects the junior medical students as well as their choices of future employment and communication styles between patients and them,which may have important significance for avoiding medical disputes.Society,schools and the media should actively create a good atmosphere for the doctor-patient relationship.

OBJECTIVE: To explore the chronic toxicity and carcinogenicity of paclobutrazol in SD rats. METHODS: Specific pathogen free SD rats at the age of weaning were randomly divided into control group and low-,medium-,and high-dose groups according the body weight,with 120 rats in each group,half male and half female. The study of combined chronic toxicity and carcinogenicity test in rats was carried out in 2 years by feeding the rats with paclobutrazol. The doses in the 4 groups were 0. 0,11. 7,48. 5 and 193. 9 mg·kg~(-1)·d~(-1) for female rats and 0. 0,13. 5,54. 2 and 241. 9 mg·kg~(-1)·d~(-1) for male rats. The body weight of rats was weighted during the experiment. The blood routine,blood biochemistry,organ coefficient and histopathology examinations were performed at the end of paclobutrazol exposure. The mortality and tumor incidence in rats were calculated. RESULTS: The decrease of body weights in female and male rats in dose groups was observed at 1-2 weeks after the experiment,compared with the same sex control group at the same time point( P < 0. 05).At the end of the exposure,the body weights of female and male rats in all three dose groups were lower than that in the same sex rats of control group( P < 0. 05). The mortality rates of female and male rats in the four groups were not significantly different( P > 0. 05). The brain organ coefficients of female rats in the three dose groups were higher than those female rats in the control group( P < 0. 05). The organ coefficients of liver,kidney and ovary of female rats in highdose group were higher than that of female rats in control group( P < 0. 05). The level of total bilirubin in male rats in the three dose groups was lower than that in control group( P < 0. 05). The organ coefficients of brain and lung in male rats in the medium-and high-dose groups were higher than that in the control group( P < 0. 05). The liver organ coefficient in male rats in the high-dose group was higher than that in the control group( P < 0. 05). A total of 244 rats had 402 spontaneous tumors with a tumor incidence rate of 50. 8%(244/480). The incidence of tumor in control,low-,mediumand high-dose groups were 61. 7%( 74/120), 42. 5%( 51/120), 50. 0%( 60/120) and 49. 2%( 59/120)respectively. There was no statistical significance in the incidence of tumors in three dose groups compared with that of the control group. CONCLUSION: Under the dose conditions designed in this study,the lowest observed adverse effect level of paclobutrazol were 11. 7 and 13. 5 mg · kg~(-1)· d~(-1) in females and males respectively. Paclobutrazol was not found carcinogenic to SD rats.

OBJECTIVE: To explore the molecular mechanism underlying 1,2-dichloroethane(1,2-DCE) induced apoptosis by screening differentially expressed proteins in human astrocytes( HAs). METHODS: HAs were cultured in complete medium with 1,2-DCE at various concentrations of 0-80 or 0-40 mmol/L. After 24 hours,apoptosis of HAs was evaluated using flow cytometry and staining with annexin Ⅴ-fluoresce in isothiocyanate and propidium iodide. An AAH-APO-1-2 protein chip was used to screen differentially expressed proteins and quantitative real-time polymease chain reaction(qRT-PCR) was used to verify related differentially expressed genes(DEGs). RESULTS: At 1,2-DCE concentrations of0-80 mmol/L,the total apoptosis rate of HAs increased with 1,2-DCE concentrations in a dose-dependent manner( P <0. 01). Seven different kinds of proteins were screened out by apoptotic protein chip. Among them,the expression of insulin-like growth factor-binding protein( IGFBP)-1,IGFBP-4 and cytochrome C( Cyto C) were up-regulated,while the expression of P27,cysteine aspartic acid specific protease-3( Caspase-3),B-cell lymphoma-2 interacting mediator of cell death( BIM) and BH3 interacting domain death agonist( BID) were down-regulated compared with the control group. The result of DEGs verified by qRT-PCR showed that the expression of mRNA of IGFBP-1,IGFBP-4 and Cyto C at 1,2-DCE concentrations of 40 mmol/L was up-regulated. This result was in consistent with the trend of target expression in the protein chip. The mRNA expression of Caspase-3,BIM and BID was also up-regulated. CONCLUSION: 1,2-DCE induces apoptosis of HAs through mitochondrial pathway.

OBJECTIVE: To explore the non-neoplastic hepatic lesions in SD rats at different ages. METHODS: The specificpathogen free SD rats were collected from the blank control groups used in subacute toxicity tests,subchronic toxicity tests and chronic toxicity combined with carcinogenic tests for safety evaluation. At the end of each experiment,i. e. week 10,19,56 and 108(assigned into four groups: 10,19,56 and 108 weeks,each contained 100 rats with each sex),rats were executed. The liver organ coefficient was calculated,the pathological examination was performed,and the non-tumorous lesions in the liver were analyzed. RESULTS: The liver organ coefficients at the age of 19,56,108 weeks were lower than that of 10 weeks(P < 0. 05); those at the age of 56 and 108 weeks were lower than that of 19 weeks(P < 0. 05),and that of 108 weeks was greater than of 56 weeks(P < 0. 05). Among the 10-week-old,19-week-old,56-week-old and 108-week-old groups,the types of non-neoplastic hepatic lesions detected in the female rats were 6,6,13 and 15 respectively,meanwhile those in the male rats were 6,6,13 and 15 respectively. Both male and female rats,the incidences of hepatocyte fatty degeneration,edema and hepatic infiltration of inflammatory cells were significantly increased with the increase of age in each group(P < 0. 05). The incidences of intrahepatic bile duct proliferation and intrahepatic bile duct fibrosis in rats at the age of 56 and 108 weeks were higher than those at the age of 10 and 19 weeks(P < 0. 008).Moreover,the frequency of hepatic sinus expansion lesions in rats at the age of 108 weeks was higher than those of 19 weeks(P < 0. 008). CONCLUSION: Spontaneous non-neoplastic lesions in the liver of SD rats were common,primarily demonstrated as hepatocyte fatty degeneration,edema and infiltration of inflammatory cells. The incidences of lesions increased with the increase of age.

OBJECTIVE: To explore the spontaneous non-tumor lesion of kidney and its correlation with different age and sex in SD rats. METHODS: Eight hundred specific pathogen free SD rats were collected from the blank control groups used in subacute toxicity tests,subchronic toxicity tests and 1 or 2 years of chronic toxicity combined with carcinogenic tests. Rats were randomly divided into 4 groups with 10,19,56 or 108 weeks of experimental periods. Each group consisted of 100 female and 100 male rats. The renal tissues were collected at the end of each experiment,and the renal organ coefficients were calculated. The pathological non-tumor changes of the kidneys were analyzed. RESULTS: The renal organ coefficients in female rats at the age of 56 and 108 weeks were both lower than that of 10 and 19 weeks( P < 0. 008). The renal organ coefficient of male rats at the age of 56 weeks was lower than that of 10 and 19 weeks( P < 0. 008). The renal organ coefficient of male rats at the age of 108 weeks was higher than that of 56 weeks( P < 0. 008). The renal organ coefficient of male rats at the age of 108 weeks was higher than that of female rats of 108 weeks( P < 0. 008). The incidence of renal tubular calcium salt deposition,interstitial inflammatory cell infiltration and renal tubular dilatation in the female rats at the age of 108 weeks were higher than those in the male rats at the age of 108 weeks( P < 0. 05). The chronic progressive nephropathy incidence of female rats at the age of 108 weeks was lower than that of male rats aged 108 weeks( P < 0. 01).The renal tubular calcium salt deposition incidence of female rats aged 56 weeks was higher than that of male rats aged 56weeks( P < 0. 01). CONCLUSION: The spontaneous non-tumor lesions in the kidney of SD rats were common. The incidence of some lesions was different in the same age group with different sex.

OBJECTIVE: To compare the effects of different anesthetics and blood sampling methods on blood routine test results in experimental animals. METHODS: A total of 42 specific pathogen free( SPF) male Sprague Dawley( SD) rats and 59 SPF male Kunming( KM) mice were randomly divided into 4 groups( control group,ether group,chloral hydrate group and pentobarbital sodium group). Ether group animals were treated with ether inhalation anesthesia; animals in chloral hydrate group and pentobarbital sodium group were injected intraperitoneally with chloral hydrate or pentobarbital sodium. The control group received no anesthesia treatment. Blood samples were collected by different ways: orbital venous plexus,abdominal aorta or eyeball enucleation. White blood cell( WBC) count,red blood cell( RBC) count,platelet(PLT) count,hemoglobin(Hb) level and hematocrit(HCT) in blood samples were analyzed. RESULTS: The RBC count,Hb level and HCT of SD rats in pentobarbital sodium group were significantly lower than those in control group( P <0. 05). The HCT of SD rats in ether group was lower than that in control group( P < 0. 05). The WBC count of orbital venous plexus of KM mice was lower than that taken by eyeball enucleation in control group( P < 0. 05),but the WBC count of orbital venous plexus was higher than that taken by eyeball enucleation in chloral hydrate group( P < 0. 05). The RBC count,Hb level,HCT of KM mice in pentobarbital sodium group were significantly lower than those in control group(P < 0. 05). CONCLUSION: The anesthetic can affect the blood routine test results of experimental animals. Different blood sampling methods have effects on blood routine test results of KM mice.