Objective To establish the plane strain model of brain tissues on mid-sagittal plane and discuss the relation between the brain tissue deformation and brain injury. Methods By referring to the computerized tomography pictures of the human body and using plane strain and finite element method (FEM), we applied plane strain hypothesis to establish a model for calculation of the brain tissue deformation caused by rotational inertia loading during vehicle crash accident. Results At the 12th ms, the shear strain field adjacent to parietal lobe reached 0.148 and the maximum positive shear stress located at white material of the cerebellum was up to 8 088.0 Pa. At the 28th ms, the maximum shear stress located at the cerebellum reached 900.9 Pa. Great shear strain existed in the cerebrospinal fluid region all the time and shear stress with large absolute value presented on the boundary of white matter and gray matter. Conclusions Under rotational inertia loading, the shear strain (stress) in brain tissues can lead to diffuse axonal injury. The uneven strain (stress) may cause serious avulsion damage in brain tissues.

Objective There is still controversy over the effect of hyperglycemia on the tolerance of heart to ischemia/reperfusion(I/R)injury in patients with diabetes mellitus. The aim of this study was to evaluate the effect of hyperglycemia on I/R-induced ventricular arrythmia in isolated diabetic rat hearts. Methods Twenty-four healthy male SD rats weighing 210-250g were randomly divided into two groups: control group(C, n=10) and diabetes mellitus group(DM, n=14). Diabetes mellitus was induced by intraperitoneal injection of streptozotocin 60 mg?kg~(-1). Blood glucose was measured 72h later and every week thereafter. Diabetes mellitus was defined as persistent hyperglycemia(blood glucose≥16.7 mmol/L after meal). The diabeticrats received no insulin. The rats were anesthetized with pentobarbital 60mg?kg~(-1). The hearts were immediately removed and perfused with oxygenated(95% O_2, 5% CO_2)Krebs-Henseleit buffer(KHB)in a Langendorff apparatus at a constant perfusion pressure of 80 mm Hg. The 14 diabetic rats were further divided randomly into 2 subgroups: (1)DM+KHB (n=7) and (2) DM+GLU(n=7) in which glucose 3.6 g was added to KHB 1000ml. After 20 min equilibration all hearts were subjected to 30 min global ischemia followed by 40 min reperfusion. Epicardial electrocardiogram was monitored. The incidence of ventricular tachycardia(VT) and ventricular fibrillation(VF) and their duration were measured. The severity of arrhythmia was quantified by arrythmia score(AS). Coronary outflow was collected for determination of creatine kinase(CK) release. Results The incidence of ischemia-induced arrythmia was significantly lowered in diabetic hearts. The incidence of VT was 14.3% and VF 28.6% in DM+KHB subgroup as compared to 60%(VT) and 100%(VF) in the control group. The CK release was significantly lower in diabetes group(DM) than in control group(C); furthermore the CK release in DM=KHB subgroup was lower than that in DM=GLU subgroup. Conclusion Diabetic rat hearts are less susceptible to I/R induced arrythmia. Hyperglycemic perfusion reduces to some extent the increased tolerance to I/R injury in diabetic rat hearts as shown by increased CK release in DM+GLU subgroup but hyperglycemic perfusion has anti-arrhythmic action as shown by 0% incidence of VT and VF in DM+GLU subgroup.

Objective To investigate the effects of long-term high-fat diet and the modern lifestyle of more food and lack of exercise on insulin resistance and islet function. Methods 75 Wistar rats were feed by routine or high-fat diet for 11 months. Some of high-fat rats were induced to diabetic models by injecting 12mg/kg streptozotocin. Islet function was evaluated by intraperitoneal glucose tolerance test. Insulin sensitivity was detected by insulin tolerance test. Results Compared with control group, 2h blood glucose of high-fat group was elevated significantly. Fasting blood glucose of high-fat group was also elevated at eleventh month. Body weight of high-fat group was increased remarkably compared with control group, and the insulin sensitivity of high-fat group was decreased by 50% at forth month. Then insulin sensitivity of both groups was declined greatly. Hypoglycemic effect of 0.5 U/kg insulin at ninth month was similar to that of 0.1U/kg insulin at forth month. Furthermore, no significant difference of insulin sensitivity was observed between high-fat group and control. Conclusions Main course for insulin resistance is the modern lifestyle of more food and lack of exercise. The main effect of high-fat diet on the occurrence of diabetes is damaging islet function.

Objective:To learn the mental health state of the Guangzhou medical students.Method:Symptom Check List 90(SCL-90) was selected to investigate 605 medical students in Guangzhou Medical College from the first year to the fifth year by stratified cluster sampling.The results were compared with the three regular models of the country.Conclusion:The mental health of the Guangzhou medical students is a little worse than that of the regular model of the adult in the country but is better than that of the regular models of the youth and the college students in the country.(except the body symptom)

Objective: To study influence of glycosylated hemoglobin A1c (HbA1c) on major adverse cardiovascular events (MACE) in patients with diabetes mellitus (DM) complicated coronary heart disease (CHD) after percutaneous coronary intervention (PCI).Methods: A total of 100 DM+CHD patients after PCI were selected from our hospital.According to HbA1c level, they were divided into HbA1c<6.5% group (n=48) and HbA1c≥6.5% group (n=52).Levels of C reactive protein (CRP), tumor necrosis factor α (TNF-α), erythrocyte sedimentation rate (ESR) and interleukin (IL)-6 before PCI, incidence rate of MACE on six and 24 months after PCI were compared between two groups.Results: Compared with HbA1c<6.5% group before PCI, there were significant rise in serum levels of CRP[(18.5±6.2) mg/L vs.(25.8±4.2) mg/L]and TNF-α[(32.4±12.3) ng/L vs.(48.3±11.8) ng/L]in HbA1c≥6.5% group, P<0.01 both.On six months after PCI, incidence rate of myocardial infarction in HbA1c≥6.5% group was significantly higher than that of HbA1c<6.5% group (9.62% vs.0, P=0.028);24 months after PCI, compared with HbA1c<6.5% group, there were significant rise in incidence rates of myocardial infarction (2.08% vs.15.38%) and diseased vessel restenosis (12.50% vs.32.69%) in HbA1c≥6.5% group (P<0.05 all).Conclusion: In DM+CHD patients after PCI, those with lower HbA1c level possess better prognosis.

Objective To investigate the effect of propofol and midazolam on the serum vascular endothe lial growth factor (VEGF) concentration and granulocyte colony-stimulating factor (G-CSF)-induced bone marrow stem cell (BMSC) mobilization after acute myocardial infarction in rats.Methods Thirty-six male Wistar rats,weighing 250-280 g,were anesthetized with intraperitonel 1％ pentobarbital 45 mg/kg.Acute myocardial infarct was induced by ligation of left anterior descending branch of coronary artery.BMSC mobilization was induced by intraperitoneal injection of G-CSF for 5 days.On 7th day after BMSC mobilization,the rats were equally and randomly divided into three groups:G-CSF group (group G),midazolam group (group M) and propofol group (group P).In group G,normal saline was continuously infused via the femoral vein at a rate of 0.5 ml/h for 6 h.In group M,midazolam was infused via the femoral vein at 0.05 mg· kg - 1 · h- 1 for 6 h.In group P,propofol was infused via the femoral vein at 5 mg·kg1 -h-1 for 6 h.Blood samples were obtained from the femoral vein after administration to determine the number of CD34+ monocyte (CD34+ MNC) and endothelial progenitor cells (EPCs) by flow cytometry and the serum concentration of VEGF by ELISA.Six rats from each group were chosen 4 weeks after myocardial infarction for measurement of the left ventricular end-diastolic pressure (LVEDP) and ± dp/dtmax Results Compared with group G,the number of CD34 + MNC and EPCs,the serum concentration of VEGF,and the absolute value of - dp/dtmax were significantly increased,while LVEDP was significantly decreased in group ( P ＜0.05),and LVEDP was significantly decreased,and the absolute value of - dp/dtmax was significantly increased in group P ( P ＜ 0.05).Compared with group P,the number of CD34+ MNC and EPCs,the serum concentration of VEGF,and the absolute value of - dp/dtmax were significantly increased,while LVEDP was significantly decreased in group M (P ＜ 0.05).Conclusion Midazolam can promote the release of VEGF,strengthen G-CSF-induced BMSC mobilization and improve the cardiac function after acute myocardial infarction in rats.Propofol can not promote the release of VEGF and produce G-CSF-induced BMSC mobilization after acute myocardial infarction in rats.

Objective To explore the expression of Her-2 and the effect on the initiation,development,invasion and metastasis of pancreatic carcinoma.Methods A total of 225 patients with pancreatic carcinomafrom January 2000 to December 2007 were analyzed retrospectively.Paraffin sections of surgical specimens from all the patients who underwent standard resection were examined by SP immunohistochemical method staining.The expression of Her-2 in patients with pancreatic carcinoma and the association between Her-2 and other clinical and pathological parameters were examined.Results Her-2 was positive in 87 of all the 225 patients(38.67%).The differentiation of tumors;size of tumors;lymph node metastasis and other organs metastasis were significantly related to Her-2.The surrival time of the Her-2-positive patients[(19.33±8.15)/nonths]Was significantly shorter than that of the Her-2-negative patients [(36.23±15.44)months]in the univariate analysis(P<0.01).At multivariate COX proportional hagards model analysis,the positivity of Her-2 applied to be an independent prognostic factor,which was also influenced by size of tumors;lymph node metastasis and other organs metastasis.Conclusion It suggests the incidence of Her-2 play an important role in evaluation of the prognosis of pancreatic carcinoma,and it could serve as an independent predictor of prognosis of pancreatic carcinoma.

Objective To observe the efficacy and safety of recombinant tissue type plasminogen activa-tor (rt-PA)for the treatment of the patients with wake-up ischemic stroke (WUS)under the guidance of multimode CT. Methods Eighteen patients with WUS (a thrombolytic group)suitable for intravenous thrombolysis after multimode CT imaging screen at the Department of Neurology,Shiyan Hospital of Integrated Traditional and Western Medicine,Hubei Province from October 2012 to October 2014 were enrolled retrospectively. Twenty patients with WUS (a control group)who underwent multimode CT imaging screen were suitable for intravenous thrombolysis,but because of exceeding time window or rejecting thrombolysis and other reasons without having intravenous thrombolysis from February 2012 to February 2014 were enrolled retrospectively. The control group was treated with conventional therapy and the thrombolytic group was treated with rt-PA (0. 9 mg/kg)intravenous thrombolytic therapy. The indicators including fibrinogen (Fib),coagulation function (prothrombin time [PT ]),activated partial thromboplastin time (APTT ), platelet (PLT ),high-sensitivity C-reactive protein (hs-CRP ),National Institute of Health Stroke Scale (NIHSS )scores,and activities of daily living scores (Barthel index)at before treatment and 24 h,7 and 14 days after treatment were observed respectively. The adverse events and complications were documented and compared with the control group. Results There were no significant differences in Fib,PT,APTT, PLT,hs-CRP,NIHSS score and Barthel index before treatment between the thrombolytic group and the con-trol group (all P>0. 05);at day 7 and 14 after treatment in the thrombolytic group,compared with before treatment,Fib (14 d after treatment),PLT,and hs-CRP were decreased,PT and APTT were prolonged,the NIHSS scores were decreased,and Barthel indexes were increased. There were significant differences (all P<0. 05). At day 14 after treatment,there were significant differences in Fib,PT,APTT,hs-CRP,NIHSS scores,and Barthel indexes (Fib:3. 25 ± 0. 38 g/L vs. 3. 55 ± 0. 28 g/L;PT:15. 7 ± 3. 2 s vs. 12. 9 ± 2. 5 s;APTT:42. 7 ± 3. 5 s vs. 38. 7 ± 2. 6 s;PLT:[189 ± 26]× 109/L vs. [201 ± 23]× 109/L;hs-CRP:5. 7 ± 0. 6 mg/L vs. 11. 3 ± 2. 2 mg/L;NIHSS scores:5. 6 ± 2. 4 vs. 9. 2 ± 4. 5;and Barthel indexes:68 ± 15 vs. 47 ± 5)between the two groups (all P <0. 05). Except 1 patient occurred symptomatic intracerebral hemorrhage after thrombolysis,no other serious complications were observed in the thrombolytic group. One patient in the control group had stress gastric ulcer and bleeding,no symptomatic intracerebral hemorrhage occurred. Conclusion Multimode CT guidance can be used as a reliable imaging evidence for patients with WUS expanding intravenous thrombolytic time window. Under the multimode CT guidance, using rt-PA for intravenous thrombolytic therapy has a certain efficacy.

A three-dimensional finite element model of premaxillary bone and anterior teeth was established with ANSYS 13.0. The anterior teeth were fixed with strong stainless labial archwire and lingual frame. In the horizontal loading experiments, a horizontal retraction force of 1.5 N was applied bilaterally to the segment through hooks at the same height between 7 and 21 mm from the incisal edge of central incisor; in vertical loading experiments, a vertical intrusion force of 1.5 N was applied at the midline of lingual frame with distance between 4 and 16 mm from the incisal edge of central incisor. After loading, solution was done and displacement and maximum principle stress were calculated. After horizontal loading, lingual displacement and stress in periodontal membrane (PDM) was most homogeneous when the traction force was 14 mm from the edge of central incisor; after vertical loading, intrusive displacement and stress in PDM were most homogeneous when the traction force was 12 mm from the incisal edge of central incisor. The results of this study suggested that the location of center of resistance (CRe) of six maxillary anterior teeth is about 14 mm gingivally and 12 mm lingually to incisal edge of central incisor. The location can provide evidence for theoretical and clinical study in orthodontics.
Dental Models ; Dental Stress Analysis ; Finite Element Analysis ; Humans ; Incisor ; Maxilla ; Periodontal Ligament ; Tongue

Objective To evaluate the effects of ulinastatin pretreatment on cognitive dysfunction induced by chronic exposure to ketamine in immature mice.Methods Thirty-six healthy male C57BL/6 mice,aged 21 days,weighing 20-30 g,were randomly divided into 3 groups (n =12 each) using a random number table:control group (group C),ketamine group (group K),and ulinastatin pretreatment group (group U).In K and U groups,ketamine 30 mg/kg was injected intraperitoneally three times a day at 30-minute intervals for 21 consecutive days,while in group U,ulinastatin 50 000 U/kg was injected intraperitoneally at 30 min before the first injection of ketamine everyday.Cognitive function was assessed using Morris water maze and open field tests at 24 h after the last administration of ketamine.Mice in each group were sacrificed immediately after the end of the tests and hippocampi were harvested to determine the contents of interleukin-6 (IL-6),IL-1 and tumor necrosis factor-α (TNF-α) using ELISA.Results Compared with group C,the escape latency was significantly prolonged,the time spent in the original platform and in the central area for the open field was shortened,the frequency of crossing the original platform was decreased,and the contents of IL-1,IL-6,and TNF-α were increased in group K (P ＜ 0.05),while there were no significant differences in the indexes mentioned above in group U (P ＞ 0.05).Compared with group K,the escape latency was significantly shortened,the time spent in the original platform and in the central area for the open field was prolonged,the frequency of crossing the original platform was increased,and the contents of IL-1,IL-6,and TNF-α were decreased in group U (P ＜ 0.05).Conclusion Ulinastatin pretreatment can improve cognitive dysfunction induced by chronic exposure to ketamine in immature mice,and inhibition of inflammatory responses in hippocampi may be involved in the mechanism.