Objective To study the effect of acupuncturing at Jiaji points plus cervical traction in treating unsteady lower cervical vertebrae.Methods The 90 outpatients willing to accept our treatment were randomized into 3 groups with 30 in each.Acupuncture group:acupuncture at the cervical Jiaji points.Traction group:traction at the cervical vertebrae.Acupuncture + traction group:acupuncture at the cervical Jiaji points plus cervical traction.Total effect,symptom scoring and X-ray examination were evaluated after 3 course of treatment.Results The total effective rate of acupuncture group,traction group and acupuncture + traction group was 47.67%,73.33% and 90.00% respectively.In total effect,symptoms of unsteady lower cervical vertebrae and the changes of X-ray examination,acupuncture + traction group was better than that of acupuncture group(P

Objective To characterize angular dependency of MatfiXX and develop a method for its calibration in order to verify treatment plan with original gantry angles.Methods Absolute dose calibration was carried with thimble ionization chamber on the linear accelerator.so as to make sure 1 MU=1 cGy at the depth of maximum dose(dmax).A MatriXX was put into a Mutlicube phantom,and the ionization chamber matrix was calibrated with absolute dose.In order to determine a correction factor CF as a function of gantry angle θ.open beam fields of 10 cm×10 cm size were irradiated for gantry angles θ=0°-180°(every 5°)and every 1°for lateral angles θ in the range of 85°-95°.CF was defined as the ratio of the dose measured with ionization chamber and the dose from MatriXX.Results Relatively large discrepancies in response to posterior VS.anterior fields for MatriXX detectors(up to 10%)were found during the experiment and relatively large variability of response as a function of gantry angle.The pass rate of treatment plan in lateral beams was lower than that of other beams.The isodose distribution of corrected MatriXX matched well with the outcome from the treatment planning system. Conclusions The angular dose dependency of MatriXX must be considered when it is used to verify the treatment plan with original gantry angles.

Objective To evaluate the effects of different concentrations of remifentanil on the expression and distribution of gap junction protein connexin 43 (Cx43) in the cardiomyocytes of rabbits.Methods Healthy adult rabbits of both sexes,weighing 2.0-2.5 kg,were anesthetized with pentobarbital sodium.Their hearts were rapidly excised and retrogradely perfused in a Langendorff apparatus with K-H solution saturated with 95％ O2-5％ CO2 at 37 ℃.After 15 min of stabilization with K-H solution,the 24 isolated hearts were randomly divided into 4 groups (n =6 each) using a random number table:control group (group C),and low,medium and high concentrations of remifentanil groups (R1-3 groups).The hearts were continuously perfused with K-H solution at 37 ℃ in group C.The hearts were perfused for 60 min with K-H solution containing remifentanil 12,25 and 50 ng/ml in R1-3 groups,respectively.The myocardial specimens were then obtained from the anterior wall of the left ventricle for detection of the expression and distribution of Cx43 by Western blot and immunohistochemistry,respectively.Results The expression of Cx43 was gradually down-regulated in C and R1-3 groups in turn (P＜0.05).Compared with group C,there was a tendency for the proteins localized at end-to-end contact sites of ventricular cardiomyocytes to localize at side-to-side contact sites in R1-3 groups,and the distribution was messy in R1-3 groups.Conclusion Remifentanil dose-dependently down-regulates the expression of Cx43 and changes the distribution of Cx43,which may be one of the mechanisms of remifentanil-induced arrhythmia in rabbits.

AIM:To study the effect of remifentanil on monophasic action potential and transmural dispersion of repolarization (TDR) in the 3-layer myocardium of isolated rabbit hearts .METHODS:Adult rabbits (n=18, 2.0 ~2.5 kg) were used to isolate the hearts for preparing Langendorff perfusion model .The hearts were randomly divided into 3 groups after perfusion with K-H solution for 15 min: the perfusion in control group ( C group ) continued for 60 min; the hearts in remifentanil group ( R group ) were perfused with 12 μg/L remifentanil K-H solution for 60 min; the hearts in remifentanil+aminophylline group ( RA group ) were given 60-min perfusion of 12 μg/L K-H remifentanil +30 mg/L aminophylline .The HR and 3 layers of myocardial monophasic action potential ( MAP) in the left ventricular anterior wall were recorded at time points after balanced infusion for 15 min ( T0 ) , and continued perfusion for 15 min ( T1 ) , 30 min ( T2 ) and 60 min ( T3 ) .The monophasic action potential duration of repolarization at 90%( MAPD90 ) and the transmural dispersion of repolarization (TDR) were calculated.The early afterdepolarization, delay afterdepolarization and arrhythmia were also observed.RESULTS:In R group, slower HR and prolonger MAPD90 and TDR at T1 ~T3 were observed as com-pared with those at T0(P<0.05).R group showed slower HR and longer MAPD 90 and TDR than C group and RA group (P<0.05).CONCLUSION:Remifentanil slows the HR, extends the MAPD90 and increases the TDR, thus being prone to induce reentry.Aminophylline makes HR faster and MAPD90 shorter, thereby reducing the TDR.

OBJECTIVETo study the effect of excessive fluoride on calcium overload and apoptosis in cultured rat ameloblasts in vitro.

METHODSLogarithmic-phase ameloblasts (HAT-7) were treated with 0, 0.4, 0.8, 1.6, 3.2, and 6.4 mmol · L(-1) sodium fluoride (NaF) solution. Cell activities were detected by using a Cell Counting Kit 8 (CCK-8) assay after 48 h of treatment. The effect of fluoride on cell apoptosis was analyzed by using flow cytometry. Excessive fluoride-induced calcium concentration and calreticulin expression changes in ameloblasts were detected by using laser scanning confocal microscopy, Western blot analysis, and real-time quantitative polymerase chain reaction.

RESULTSNaF inhibited ameloblast activity at 1.6, 3.2, and 6.4 mmol · L(-1) (dose-dependent) after 48 h of induction. The Ca2+ fluorescence intensity of HAT-7 cells incubated with 1.6 and 3.2 mmol · L(-1) NaF was higher than that in the control group. The fluoride-induced early-stage apoptosis of ameloblasts after 48 h of induction and the early-stage apoptosis rate was positively correlated with fluoride concentration. Calreticulin mRNA expression in HAT-7 cells was higher than that in the control group after 48 h of incubation with 0.8, 1.2, and 1.6 mmol · L(-1) NaF.

CONCLUSIONExcessive fluoride-induced calcium overload in ameloblasts and further caused endoplasmic reticulum stress-mediated apoptosis.

Objective To investigate the dosimetric performance of COMPASS system,a novel 3D quality assurance system for the verification of nasopharyngeal carcinoma volumetric modulated therapy (VMAT) treatment plan.Methods Eight VMAT treatment plans of nasopharyngeal carcinoma patients were performed with MasterPlan,a treatment planning system (TPS),and then these treatment plans were sent to the COMPASS and MOSAIQ system,a coherent control system,respectively.Comparison of the COMPASS reconstructed dose versus TPS dose was conducted by using the dose volume-based indices:dose received by 95％ volume of target ( D95％ ),mean dose ( Dmean ) and γ pass rate,dose to the 1％ of the spinal cord and brain stem volume ( D1％ ),mean dose of leaf and right parotid ( Dmean ),and the volume received 30 Gy for left and right parotid (V30).COMPASS can reconstruct dose with the real measured delivery fluence after detector commissioning.Results The average dose difference for the target volumes was within 1％,the difference for D95 was within 3％ for most treatment plans,and the γ pass rate was higher than 95％ for all target volumes.The average differences for the D1％ values of spinal cord and brain stem were ( 4.3 ± 3.0) ％ and ( 5.9± 2.9 ) ％ respectively,and the average differences for the Dmean values of spinal cord and brain stem were ( 5.3 ± 3.0 ) ％ and ( 8.0 ± 3.5 ) ％ respectively.In general the COMPASS measured doses were all smaller than the TPS calculated doses for these two organs.The average differences of the Dmean values of the left and right parotids were( 6.1± 3.1 ) ％ and ( 4.7 ± 4.4 ) ％ respectively,and the average differences of the V30 values of the left and right parotids were (9.4 ± 7.5 ) ％ and (9.4 ± 9.9)％ respectively.Conclusions An ideal tool for the VMAT verification,the patient anatomy based COMPASS 3D dose verification system can check the dose difference between the real delivery and TPS calculation directly for each individual organ,either target volumes or critical organs.

Objective To compare the static intensity-modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) for mid and upper thoracic esophageal cancer.Method The data of twenty esophageal cancer patients were retrospectively re-planned with VMAT(single arc and double arcs) modality using Pinnacle treatment plan system.Five of these patients were selected again to simulate single arc plans with different segment intervals (4°,3°,2°) and re-planned on other treatment planning systems (Monaco and MasterPlan).Differences of dose distribution and treatment parameters were compared.Results In comparison to IMRT and single-VMAT (S-VMAT),Double-VMAT (D-VMAT) significantly improves the dosimetric parameters for targets(P ＜ 0.05),dose homogeneity(P ＜ 0.05) and conformity(P ＜ 0.05).Though VMAT plans were slightly better than IMRT in reducing the doses to the organs at risk (OARs),no advantage was observed in the low-dose protection of lung and E-P (P ＜ 0.05).For the VMAT plans with different segment intervals,lower OAR doses were observed using an interval of 2°(P ＜ 0.05),except for the mean dose of the heart.For the VMAT plans on different treatment planning systems,Monaco-based plans protected OARs better (P ＜ 0.05).The number of monitor units (MU) and treatment time were less in VMAT cases.Conclusions VMAT plans perform better in target coverage,dose homogeneity and conformity,and can reduce the radiation dose to the spinal cord,lungs,heart and other normal tissue than IMRT plans.The VMAT plan quality could be further improved by using double arcs and smaller segment interval.Monaco-based plans provide better OAR protections under the same conditions of physical and optimization parameters.

Objective To evaluate the effects of different concentrations of remifentanil on myocardial monophasic action potential (MAP) in isolated rabbit hearts.Methods Adult rabbits of both sexes,weighing 2.0-2.5 kg,were used in the study.Their hearts were excised,and retrogradely perfused with oxygenated K-H solution saturated with 95％O2-5％CO2 at 37 ℃ in a Langendorff apparatus.Twenty-four isolated hearts were randomly divided into 4 groups (n =6 each) using a random number table:control group (group C) and 3 different concentrations of remifentanil groups (group R1-3).After 15 min of stabilization,K-H solution was continuously perfused for 60 min in group C,and K-H solution containing 12,25 and 50 ng/ml remifentanil was continuously perfused for 60 min in R1,R2 and R3 groups,respectively.At 15 min of stabilization,and 15,30 and 60 min of perfusion with K-H solution,the heart rate,and the maximal velocity and amplitude of the MAP in the three layers of the left ventricular anterior wall were recorded,and the action potential duration at 90％ repolarization and transmural dispersion of repolarization (TDR) were calculated.Results Compared with group C,the heart rate was significantly decreased,and the action potential duration at 90％ repolarization and TDR were significantly prolonged at 15,30 and 60 min of perfusion in R1-3 groups (P＜0.05).Compared with C and R1 groups,the maximal velocity and amplitude of MAP were significantly decreased at 15,30 and 60 min of perfusion in R2 and R3 groups (P＜0.05).Conclusion Low-concentration remifentanil induces heart block through increasing TDR,however,high-concentration remifentanil induces heart block through inhibiting myocardial MAP depolarization and increasing TDR in the isolated rabbit hearts.

Objective To study the effects of dexmedetomidine on the monophasic action po-tential duration and the transmural dispersion of repolarization during ischemia-reperfusion of isolated rabbit hearts and thus explore its effect on myocardial ischemia-reperfusion electrophysiological char-acteristics.Methods Eighteen healthy adult rabbits,weighing (2.0±0.5)kg,were randomly divided into 3 groups after successful preparation of Langendorff isolated heart perfusion model and 1 5 min perfusion and balance of K-H fluid.In the control group (group C),37 ℃ K-H fluid was continuously perfused and balanced for 1 50 min.In the ischemia/reperfusion group (group IR),K-H fluid was stopped after continuous perfusion and balance for 1 5 min and cardiac arrest was induced for 60 min with the injection of Thomas solution (4 ℃,10 ml/kg)while the heart was protected by the low tem-perature Thomas solution (4 ℃)around it.Reperfusion of Thomas solution (4 ℃,5 ml/kg)was performed for 30 min and the heart was resuscitated by the perfusion of K-H fluid for 60 min.In dexmedetomidine group (group DEX),dexmedetomidine (25 ng/ml)was added in the K-H fluid and the Thomas solution.Other procedures were same as in group IR.Heart rate(HR),monophasic ac-tion potential amplitude (MAPA)of the three layers of heart [endocardium (Endo),myocardium (Mid)and epicardium (Epi)],0 phase maximal increase rate (Vmax),90% monophasic action po-tential duration (MAPD90 )and transmural dispersion of repolarization (TDR)were recorded at the time of continuous balance perfusion 1 5 min(T0 ),continuous perfusion 1 5 min/balance 30 min(T1 ), reperfusion 30 min/balance 120 min(T2 )and reperfusion 60 min/balance 1 50 min(T3 ).Cardiac ar-rhythmia and resuscitation time at cardiac reperfusion were observed,without using drugs to restore normal cardiac rhythm.Results In group DEX,cardiac resuscitation time was significantly shorter (1 6.67±3.78)s than that in group IR (46.33±7.29)s (P <0.05);At T2 ,in group IR,arrhythmia was seen in 6 rabbits and normal cardiac rhythm was restored within 2 min in two rabbits,while in group DEX,arrhythmia was seen in 2 rabbits and normal cardiac rhythm was restored within 2 min in one rabbit,without the use of any drugs.When compared with T0 ,HR was slower at T2 and T3 in group IR and at T1-T3 in group DEX (P <0.05);Compared with T1 ,HR was slower at T2 and T3 in group DEX (P <0.05);Compared with T2 and group C,HR was slower at T3 in group DEX;At T1-T3 ,HR in group DEX were significantly slower than that in group IR (P <0.05).Compared with T0 ,MAPD90 of Mid at T1 and Epi,Mid,Endo at T2 and T3 in group DEX were significantly extend-ed (P <0.05);Compared with T1 ,MAPD90 of Epi,Mid,Endo in group DEX were significantly ex-tended at T3 ;MAPD90 of Mid in group DEX was significantly longer than that in group C at T3 (P <0.05);At T2 and T3 ,MAPD90 of Epi,Mid,Endo in group DEX were longer than that in group IR (P <0.05).Compared with T0 and group C,TDR at T2 and T3 in group IR and at T1-T3 in group DEX significantly increased (P <0.05),while TDR in group DEX were less than that in group IR at T2 and T3 (P <0.05).Conclusion Dexmedetomidine appeared to prolong MAPD and restrain the dis-proportion of resuscitation of myocardial ischemia-reperfusion injury.Dexmedetomidine could have the effect of stabilizing myocardial ischemia-reperfusion electrophysiological characteristics.

Objective To investigate the effects of hypothermia combined with dexmedetomidine on myocardial monophasic action potentials (MAPs) in isolated rabbit hearts.Methods Adult rabbits,weighing 2.0-2.5 kg,were heparinized and anesthetized with pentobarbital sodium 30 mg/kg.Their hearts were rapidly removed and retrogradely perfused in a Langendorff apparatus at 37 ℃.Eighteen hearts were randomly divided into 3 groups (n =6 each) using a random number table:control group (group C),hypothermia group (group H),and hypothermia+dexmedetomidine group (group HD).The hearts were continuously perfused for 60 min with 37 ℃ K-H solution in group C,with 32 ℃ K-H solution in group H,or with 32 ℃ K-H solution containing dexmedetomidine 25 ng/ml in group HD.At the end of equilibration (T0) and at 15,30 and 60 min of perfusion with K-H solution,HR and MAPs of left ventricular epicardium,mid-myocardium and endocardium were recorded.MAP duration at 50％ repolarization (MAPD50) and at 90％ repolarization (MAPD90),monophasic action potential amplitude (MAPA) and maximal velocity (Vmax) were calculated.Results Compared with group C,HR was significantly decreased,and MAPD50 and MAPD90 were prolonged at each time of perfusion with K-H solution in H and HD groups.There was no significant difference in HR,MAPD50 and MAPD90 between H group and HD group.There was no significant difference in MAPA and Vmax between the three groups.Conclusion Hypothermia combined with dexmedetomidine can lead to prolongation of myocardial repolarization,and dexmedetomidine exerts no effect on hypothermia-induced change in MAPs in isolated rabbit hearts.