Objective:To study the expression of Ki67 and P53 proteins in gingival tissue after wearing four kinds of temporary crowns.Methods:The experiment animal model was established by temporary prosthesis on dogs' teeth using chemical-curing resin,thermal-curing resin,DMG-TEMP crown material and SWIFT composite resin respectively.The immunohistochemistry Envision method was used to measure the expression of Ki67 and P53 proteins in gingival tissue before tooth preparation,after tooth preparation,1-and 2-week,1 month after wearing the crowns.The teeth without any treatment were surved as control.HE stained gingival tissue slices were observed under microscope.Results:The expression of Ki67 and P53 proteins in gingival tissue increased 1 week after wearing the chemical-curing resin crowns or thermal-curing resin crowns(P0.05).No pathological change was observed in all the samples.Conclusion:Chemical-curing resin crowns and thermal-curing resin crowns may increase the expression of Ki67 and P53 proteins in gingival tissue,but DMG-TEMP crowns and SWIFT resin crowns do not.None of the four kinds of temporary crowns may cause abnormal proliferation of gingival epithelia.

Objective To investigate the changes of morphology of injured nerve after pulsed radiofrequency (PRF) and radiofrequency thermocoagulation (RFTC) on rats. Methods 55 male Wistar rats were selected, in which 5 were allocated to control group (group C) and the other 50 were randomly divided into group PRF (n=25) and group RFTC (n=25). The specimens were analyzed both with light microscopy and electron microscopy at immediate, and 1, 7, 14 and 28 d after operation. Results In group PRF, the nerve function of rats maintained after operation. The edema among nerve fibers was found under light microscope, while myelin lamellar structure disorder and myelin balls shaped, and compensatory hyperplasia of ultrastructure under electron microscopic level. Those effects were more pronounced 1 d after operation. In group RFTC, the nerve function of rats disappeared and autophagy behaviors happened, meanwhile Waller's degeneration and nerve regeneration appeared under both light microscopy and electron microscopy. Conclusion PRF and RFTC can produce destruction of nerve, but PRF was minor and recoverable.

Clinical practice is a key step that seven-year clinic student take to become doctors.Take the First Affiliated Hospital of Xi'an Jiaotong University as an example,in the medical practice of seven-year clinic students,there still exist some problems such as students' being unable to transform from probationers to doctors,not good at treating with interpersonal relationship in the department and having no perseverant practice attitude.So training before practice should be perfected and supervision should be strengthened to make the seven-year clinic students better.

OBJECTIVE: To observe the effects of rhubarb aglycone on pathological changes and activity of matrix metalloproteinase in cerebral ischemic tissue in rats with bone marrow mesenchymal stem cell (BMSC) transplantation, and to explore the action mechanisms of rhubarb aglycone in protecting against brain micrangium injury in rats. METHODS: The BMSCs were purified and amplified by methods of adherence and selection in vitro. One hundred and ninety rats were randomly divided into sham-operated group, untreated group, rhubarb aglycone group, BMSC transplantation group (abbreviated as transplantation group) and BMSCs combined with rhubarb aglycone group (abbreviated as combination group). Middle cerebral artery occlusion (MCAO) model was duplicated with nylon thread. Rats of transplantation and combination group were transplanted with BMSCs via carotid artery after 24-hour reperfusion. Rhubarb aglycone was used by intragastric administration in the rhubarb aglycone group and the combination group. The brain samples were taken at 7, 14 and 28 days after transplantation. Brain micrangium pathological changes were observed by light microscope, and immunohistochemical method was used to determine the expressions of immunoglobulin G (IgG), type IV collagen (Col IV), matrix metalloproteinase-9 (MMP-9), and tissue inhibitor of metalloproteinase-1 (TIMP-1). RESULTS: Comparison with the normal control group revealed that brain micrangium in rats in the untreated group was obviously mutilated and damaged, the expression of IgG and MMP-9 increased, and showed a progressively enhanced tendency following the prolongation of reperfusion, while the expressions of Col IV and TIMP-1 were decreased, and TIMP-1 showed a attenuated tendency following the prolongation of reperfusion. Comparing with the untreated group, the improvements of brain micrangium structure in the rhubarb aglycone group (7 days after transplantation), the transplantation group (14 and 28 days after transplantation) and the combination group were significant; expression of IgG and activity of MMP-9 were decreased, while expressions of Col IV and TIMP-1 were increased in the rhubarb aglycone group and the combination group at each time point. The brain micrangium was integral and the expression of Col IV was enhanced in combination group (7 days after transplantation) as compared with those in transplantation group. MMP-9 activity in combination group (14 days after transplantation) was lower than that in the rhubarb aglycone group (14 days after transplantation), while expression of TIMP-1 in combination group also increased significantly as compared with that in transplantation group (28 days after transplantation). CONCLUSION: Rhubarb aglycone can decrease the degradation of basal lamina Col IV and the permeability of brain micrangium in cerebral ischemic rats with BMSC transplantation, and its mechanisms may be related to regulating the balance of MMP-9, especially by increasing the expression of TIMP-1.

OBJECTIVE: To study the protective effects of Naomaitong, a compound traditional Chinese herbal medicine, used together with thrombolysis therapy, on injuries of the lung and stomach in rats with cerebral ischemia. METHODS: Rats were randomly divided into sham-operated group, untreated group, urokinase group (thrombolysis group), Naomaitong group, thrombolysis plus Naomaitong group. Cerebral ischemia was induced in rats by autonomous blood blot and inserted nylon thread. Rats were administrated with thrombolysis therapy through artery 3, 6 and 9 h after cerebral ischemia respectively. Twenty-four hours after the administration, mortality of the rats, and the brain and stomach hemorrhage ratios, as well as the pathological changes of the brain, lung and stomach were observed, and then cerebral infarct size (CIS) and lung water ratio (LWR) were measured. RESULTS: Compared with the sham-operated group, the rat mortality, and the brain and stomach hemorrhage ratios increased, the CIS enlarged, pathological changes of the brain, lung and stomach appeared obvious, and the LWR increased. Naomaitong plus thrombolysis treatment improved the changes above significantly. In the untreated rats with cerebral ischemia, injuries of the brain, lung and stomach were aggravated, the CIS enlarged and the LWR increased in the 9 h group as compared with those in the 3 h group. In the thrombolysis plus Naomaitong group, the pathological changes were improved, the CIS diminished and the LWR reduced. CONCLUSIONS: Injuries of the lung and stomach can be caused by cerebral ischemia, and the impairment was exacerbated following the prolongation of the ischemia. Thrombolysis therapy can cause brain and stomach hemorrhage. Thrombolysis therapy used early can perform protection against the injuries. Naomaitong, used together with thrombolysis, can reduce the mortality, the brain and stomach hemorrhage ratios, and perform protective effects on the injuries of cerebral ischemia.

Objective To investigate the impact of different hepatic vascular inflow occlusion methods on hepatic parenchymal function in partial hepatectomy.Methods Between 2009 and 2010,62 hepatocellular carcinoma (HCC) patients underwent partial hepatectomy.In 13 patients,partial hepatectomy was carried out without using any inflow occlusion (group A).In 29 patients intermittent Pringle's maneuver (group B) while in 20 patients selective hepatic inflow occlusion (group C) were used.Intraoperative indocyanine green retention rate at 15 minutes (ICGR15) was measured using pulse spectrophotometry before and during hepatectomy. Results (1) Blood loss in group A was greater than group B and C (P=0.016,P=0.001).(2) There was no significant difference in the preoperative ICGR15 values among group A,B and C.The intraoperative ICGR15 for group B was significantly higher than group A and C (P=0.011,P=0.030).(3) A significant correlation was found between the level of ICGR15 and total inflow clamp time (r =0.484,P =0.001) and blood loss (r=0.349,P=0.005),respectively.(4) Compared with group A and B,postoperative liver function recovered significantly faster in group C.Conclusion Selective hepatic inflow occlusion was useful in controlling blood loss and it was beneficial to the hepatic functional reserve in the liver remnant.

OBJECTIVETo study the interleukin-8 (IL-8) levels in gingival crevicular fluid (GCF) of porcelain teeth coated with Ni-Cr, Co-Cr or gold alloy at different time periods, and to uncover the degree of stimulation by these alloys on gingiva at different time periods.

METHODS45 cases of porcelain teeth coated with Ni-Cr, Co-Cr or gold alloy were selected randomly, with 15 cases in each group. Sandwich enzyme-linked immunosorbent assay (ELISA) was used to determine the concentration and total amount of IL-8 in GCF. The assay was done before treatment, as well as at 1, 3 and 6 months post-treatment.

RESULTSThe total amounts of IL-8 and GCF volume in the Ni-Cr alloy coated porcelain teeth were higher in different time period than those before treatment (P<0.05). However, the IL-8 levels in Co-Cr and gold alloy coated porcelain teeth returned to pre-dental restoration after 3 months. Otherwise, the levels of IL-8 concentration in GCF showed no significant difference among the three different alloys coating at different time periods.

CONCLUSIONIL-8 is an important cytokine during tissue inflammation. Therefore, the level of IL-8 in GCF is a useful criteria for the evaluation of stimulation degree on gingiva by different alloy coating materials in porcelain teeth. The clinical choice of different alloy coating for porcelain teeth should be considered accordingly.

Objective To investigate the changes in cerebral hemodynamics in different body positions in healthy volunteers.Methods Sixty right-handed healthy male volunteers,aged 22-26,height 167-178 cm,weighing 51-67 kg,were randomly divided into 4 groups ( n =15 each): 15 degrees head-down tilt group (group Ⅰ ),30 degrees head-down tilt group (group Ⅱ ),15 degrees head-up tilt group (group Ⅲ) and 30 degrees head-up tilt group (group Ⅳ ).Blood flow signals of right middle cerebral artery (MCA) and extracranial internal carotid artery (EICA) were detected by transcranial Doppler and systolic blood flow velocity (Vs),diastolic blood flow velocity (Vd ),mean blood flow velocity (Vm),pulsatility index (PI) and resistance index (RI) were recorded at supine position (baseline),immediately,10 and 30 min after body position change(T1-3 ).Lindegaard index was calculated.Results Compared with the baseline,in group [Ⅱ Lindegaard index was increased at T2,while Vs and Vm of MCA were decreased at T2,3,in group Ⅳ Vs of MCA and PI of EICA at T2,Vd and Vm of MCA at T2,3 were decreased ( P ＜ 0.05),while there was no significant difference in the variables mentioned above in the other two groups ( P ＞ 0.05 ).Conclusion In healthy adults,cerebral blood flow velocity decreases in 30 degrees headdown and head-up tilt positions,however there is no change in cerebral blood flow velocity in 15 degrees headdown and head-up tilt positions.

Objective To explore the activation of the primary somatosensory cortex (S_Ⅰ) and secondary somatosensory cortex (S_Ⅱ) undermild and moderate pain. Methods 7 healthy right-handed volunteers accepted electrostimulation of 1 and 2 times pain threshold respectively.The severity of pain was determined with the Visual Analogue Score (VAS), and they received functional magnetic resonance imaging(fMRI) simultaneously. Results 1 and 2 times pain threshold electrical stimulation caused mild and moderate pain respectively. Bothmild and moderate pain activated contralateral S_Ⅰ similarly, and bilateral S_Ⅱ with pain intensity. Conclusion S_Ⅰ and S_Ⅱ respond to the mildand moderate pain in different ways.