有限元分析3种单侧颞颌关节强直治疗手术模型双侧髁突表面应力分布的特点

目的:采用三维有限元法探讨正常咬合时正常下颌骨及3种单侧颞颌关节强直治疗手术模型双侧髁突表面应力分布的特点,为临床颞颌关节强直术式选择提供参考.方法:建立正常下颌骨三维有限元模型及3种单侧颞颌关节强直治疗手术模型,对各模型下颌角区及髁突横嵴中点进行固定约束,以各个模型下颌第一磨牙咬合面为承载面,分别向各模型双侧下颌第一...     

下颌骨颏部正中牵张成骨过程中颞下颌关节的应力分布

目的：建立包括下颌骨的颞下颌关节(TMJ)三维有限元模型，分析该模型在下颌骨颏部正中牵张成骨过程中颞下颌关节的应力分布特征．方法：以活体人颅为标本，用螺旋CT扫描技术、图形数字化处理在计算机上建立模型，然后在下颌骨颏部正中行水平加载，采用ANSYS6．1有限元分析软件进行分析．结果：建立了包括下颌骨的TMJ有限元模型，在此模型上进行下颌骨颏部正中牵张成骨的力学加载，此时颞下颌关节的应力分布表现为：随着加载力值的增加，关节内压应力、拉应力的大小也随着增加，但分布区域不变．压应力和拉应力均表现为外侧高于中、内侧．结论：在下颌骨颏部正中行牵张成骨时，结果提示TMJ内最大压应力部位在髁突软骨的外后，最大拉应力部位在髁突软骨的内前，对进一步研究牵张成骨过程中颞下颌关节的生物力学问题提供依据．     

下颌骨颏部骨折联合双侧髁突囊内骨折致伤机制的三维有限元分析

目的: 通过三维有限元方法模拟和分析下颌骨颏部骨折联合双侧髁突囊内骨折的致伤机制,提高此类骨折的预防和诊断水平。方法: 获取1名下颌骨发育正常、无第三磨牙、无颞下颌关节病史的青年男性的颌面部CT和颞下颌关节MRI数据,通过Mimics和ANSYS软件建立三维有限元模型。采取不同角度的外力作用于下颌骨颏部,分析下颌骨及髁突关节面的应力分布。同时,比较有无关节盘、咬合与非咬合状态下下颌骨的应力分布差异。结果: 准确建立了包含颞下颌关节结构的三维有限元模型。当外力作用于下颌骨颏部时,髁突、升支前缘及颏部受力区是主要的应力集中区,其中应力最大值位于髁突顶部。随着外力方向与水平面夹角由0°逐渐增大直至60°,下颌骨上的应力由分散逐渐集中至颏部与双侧髁突三个部位;超过60°时,应力又出现分散的趋势。当对关节盘进行模拟后,髁突关节面及髁颈部的应力分布明显减小。与非咬合状态相比,咬合状态下下颌骨上的应力集中于咬合面,而其他部位无明显的应力分布。结论: 外力方向与水平面呈60°时,应力分布主要集中于颏部及双侧髁突顶部,即三点骨折发生的部位;在下颌骨颏部受力过程中,关节盘的存在以及稳定的咬合状态下,髁突部位(包括颈部和关节面)的应力分布明显减小。     

不同加载方式及咬合部位对下颌骨应力分布的影响

目的研究不同的加载方式及不同的咬合部位对下颌骨,特别是下颌角区域应力分布的影响。方法通过建立下颌骨的机械力学模型,采用电阻应变片的测量方法,分析不同加载方式(咬肌加载,颞肌加载及咬肌、颞肌、翼内肌和翼外肌四组肌肉同时加载)以及不同咬合状态(前牙咬合及单、双侧后牙咬合)对下颌骨应力分布的影响。结果在不同的加载方式的比较中,咬肌单独加载时,下颌角区域的应变明显(上缘121με、125με,下缘-69με、-45με);颞肌单独加载时,下颌升支前缘应变明显(269με、375με);四组肌肉同时加载时,颏部的应力性质发生改变。在不同咬合部位的比较中,在四组肌肉同时加载的条件下,前牙咬合加载时下颌角区域的应力值大于双侧后牙咬合加载;单侧后牙咬合时,咬合侧下颌角区域的应力趋势发生变化。结论不同加载方式及不同咬合状态对下颌骨的应力分布有影响。     

下颌骨在撞击载荷作用下的应力分布

目的：探讨撞击载荷作用时下颌骨不同结构的应力分布规律、应力集中区域,为研究下颌骨撞击损伤的生物力学机制提供参考依据．方法：建立下颌骨三维有限元模型,在人尸体下颌骨撞击实验的基础上,分析下颌骨不同结构的受力规律．结果：①撞击颏部,其舌侧区,磨牙后区内侧面、髁状突颈外表面以及下颌角外表面具有较高的张应力;②撞击下颌体部,颏部舌侧区,对倒磨牙后区内侧面、对侧下颌角外表面、撞击侧下颌角外侧面、撞击侧体部内侧面具有较高的张应力;③撞击下颌角,其内侧面、撞击侧髁状突颈内侧面、颏部舌侧面、对侧髁状突颈外表面以及撞击侧磨牙后区内侧面具有较高的张应力．结论：下颌角、髁状突颈部、下颌体部、磨牙后区是下颌骨撞击损伤的好发部位,骨折部位与撞击部位间有一定相关关系．     

活体下颌骨与HYBRIDⅢ假人头结合模型撞击损伤的有限元研究

目的：建立活体下颌骨与HYBRIDⅢ假人头结合的人体头部有限元模型。探讨下颌骨正面撞击时响应过程，研究其损伤的生物力学机制。方法：根据人体下颌骨的螺旋CT扫描图像，利用三维重建、图像处理和网格划分技术，建立人体下颌骨的三维有限元模型。根据颞下颌关节的解剖结构及其力学特点，将已建立的下颌骨模型通过关节和经过修改的HYBRIDⅢ假人头部模型相连接，从而建立活体下颌骨与HYBRIDⅢ假人头结合的人体头部有限元模型，对下颌骨进行初步边界约束。模拟计算此模型在下颌骨正中撞击正前方刚体试验。结果：下颌骨正中撞击正前方刚体，下颌骨会以颢下颌关节为轴向后轻微滑动，因而应力上升过程中有一回落，此处为滑动力。应力沿下颌骨外斜线向升支和颞下颌关节传递，髁突及髁突颈部应力有明显集中。骨结构的横截面积陡然减小的区域出现应力集中。在喙突(颞肌)边界约束条件下，喙突应力亦有一定改变。结论：髁突及髁突颈部相对于下颌骨体其骨结构的横截面积陡然减小，同时下颌骨以髁突为轴向后轻微滑动，造成此处较强的应力有集中。从理论上，这可能是下颌骨撞击损伤的生物力学机制之一。由于将活体下颌骨与HYBRIDⅢ假人头结合，有助于对下颌骨进行边界约束。     

下颌骨三维有限元模型分析模拟咬合创伤对髁突的力学影响

目的 建立下颌骨的三维有限元模型, 模拟可导致咬合创伤的异常咬合力, 研究对髁突力学影响及位移变化, 为临床研究TMD与咬合创伤提供实验证据.方法 选咬合关系正常的男性志愿者, CBCT扫描后得到DICOM数据, 髁突顶作约束设计, 经划分网格生成有限元模型.工况一:左侧下颌第1磨牙不咬合接触面垂直加载不同负荷;工况二在同一模型上设计颊侧方向不同负荷, 研究不同工况下左侧髁突处应力分布变化的规律.结果建立了下颌骨的三维有限元模型, 随着载荷的成倍数增加, 髁突受力范围一致, 但张力和应力也成倍数增加.然后模拟咬合创伤条件下相同牙位施加相同载荷后, 应力较垂直负荷时变大, 髁突位移距离也增加, 结论形成咬合创伤的异常咬合力, 可影响髁突的力学传导, 导致髁突的病理性改变.     

三维有限元法在研究咬合板对髁突表面应力影响中的应用

目的分析5种咬合板对髁突表面应力的影响，为指导临床实践提供理论基础。方法利用下颌骨三维有限元模型，模拟5种咬合板的作用，观察髁状突表面11个区域应力变化情况。结果(1)在各种前牙接触的松弛咬合板作用下，髁突表面应力分布趋势基本相同，仅力值的大小不同；(2)枢轴咬合板对髁突表面产生的应力值均明显低于松弛咬合板。前牙接触的咬合板可增加TNJ负荷；后牙接触的咬合板可降低TNJ负荷；(3)单侧枢轴咬合板作用下，两侧髁突表面应力分布不对称。结论在不同咬合板的作用下，髁状突表面应力的分布不同，各有特点，有一定临床意义。     

具有解剖基下颌的人头模型撞击损伤的有限元研究

目的 建立具有解剖基下颌的人体头部有限元模型。探讨此模型以不同速度正面撞击的响应过程,研究其损伤的生物力学机理。方法 根据人体下颌骨的螺旋CT扫描图像,利用三维重建、图像处理和网格划分技术,建立人体下颌骨的三维有限元模型,通过关节和经过修改的混合Ⅲ型假人头部模型相连接,建立活体下颌骨与混合Ⅲ型假人头结合的人体头部有限元模型。对下颌骨进行初步边界约束,模拟计算此模型以3．6m/s和10m/s速度撞击正前方刚体。结果 下颌骨以3．6m/s速度撞击正前方刚体,下颌骨会以颞下颌关节为轴向后轻微滑动,因而应力上升过程中有一回落,此处为滑动力。应力沿下颌骨外斜线向升支和颞下颌关节传递,髁突及髁突颈部应力有明显集中;下颌骨以10m/s速度撞击时,滑动力不明显,于第4～5ms时应力回弹、反射明显导致应力叠加。活体下颌骨与混合Ⅲ型假人头结合,可对下颌骨进行边界约束。在喙突(颞肌)边界约束条件下,喙突应力亦有一定改变。结论 (1)髁突及髁突颈部相对于下颌骨体其骨结构的横截面积陡然减小,骨结构的横截面积陡然减小的区域出现应力集中;(2)撞击过程中下颌骨以髁突为轴向后轻微滑动,造成此处较强的应力有集中;(3)应力回弹、反射导致应力叠加,这是下颌骨撞击损伤的生物力学机制之一。与临床下颌骨正面撞击所造成的骨折部位完全吻合。     

三种模拟咬合板对髁突表面应力影响的比较

目的比较3种前牙接触咬合板对髁突表面应力的影响，为指导临床实践提供理论基础。方法利用下颌骨三维有限元模型，模拟3种前牙接触咬合板的作用，观察髁突表面11个区域应力变化情况。结果髁突表面应力分布趋势基本相同，仅力的大小不同。即前斜面和嵴顶区为拉应力和压应力并存，而后斜面为只有压应力，没有拉应力。三种情况的最大拉应力均位于髁突前斜面中部，最大压应力均位于嵴顶中部，VonMises应力最大值也位于嵴顶中部区域。结论在各种前牙接触的松弛咬合板作用下，髁突表面应力分布趋势基本相同，仅力值的大小不同。其中引导下颌后移位的前牙斜面咬合板在髁突表面产生的负荷最大，临床应用时应特别谨慎，防止造成TMJ损伤，而引导下颌前移位的前牙斜面咬合板在髁突表面产生的负荷最小。     

Value of D-Dimers in patients with acute aortic dissection

Objective: To evaluatel the value of D-dimers in patients with acute aortic dissection (AAD). Methods: This study consisted of 16 patients with AAD and 27 non-AAD patients. Serum D-dimets were measured by Sta-Liatest D-DI immunoturbidimetric assay. Results: D-dimer level was higher (P ＜ 0.001) in patients with AAD(7.91 ± 5.52 μg/ml) than that in non- AAD group(1.57±1.24 μg/ml). D-dimer was positive (＞0.4 μg/ml) in all patients with AAD and in 10 control group patients (37%). Among patients with acute AAD, D-dimers tended to be higher in Stanford A than in Stanford B (8.67 ± 4.31 μg/ml vs. 3.24±1.27 μg/ml, P ＜0.01). D-dimer values tended to be higher in more extended disease(3.84 ± 1.65 μg/ml, 8.57 ± 3.58 μg/ml and 11.87 ± 5.69 μg/ml in thoracic aorta, thoracic and abdominal aorta, thoracic and abdominal aorta and iliacal arteries, respectively, P ＜ 0.05 for both 8.57 ± 3.58 and 11.87 ± 5.69 vs. 3.84 ± 1.65 ). Including the control group into the analysis, we found a sensitivity of 100%, a negative predictive value of 100%, and a specificity of 66% and a positive predictive value of 64% for D-dimer in diagnosis of AAD in our patients with suspected AAD. Conclusion: D-dimer was elevated in patients with AAD. A negative D-dimer test result could be useful in excluding AAD.     

Research of combined liver-kidney transplantation model in rats

Objective： To set up a simple and reliable rat model of combined liver-kidney transplantation. Methods： SD rats served as both donors and recipients. 4℃ sodium lactate Ringer＇s was infused from portal veins to donated livers,and from abdominal aorta to donated kidneys, respectively. Anastomosis of the portal vein and the inferior vena cava （IVC） inferior to the right kidney between the graft and the recipient was performed by a double cuff method, then the superior hepatic vena cava with suture. A patch of donated renal artery was anastomosed to the recipient abdominal aorta. The urethra and bile duct were reconstructed with a simple inside bracket. Results： Among 65 cases of combined liver-kidney transplantation, the success rate in the late 40 cases was 77.5%. The function of the grafted liver and kidney remained normal. Conclusion： This rat model of combined liver-kidney transplantation can be established in common laboratory conditions with high success rate and meet the needs of renal transplantation experiment.     

BLOOD PRESSURE CHANGE WITH AGE IN SALT-SENSITIVE TEENAGERS

Objective To observe blood pressure change with age in salt-sensitive teenagers whose salt sensitivity were determined by repeated testing.Methods Salt sensitivity was determined through intravenous infusion of normal saline combined with volume-depletion by oral diuretic furosemide in 55 teenagers. After five years, salt sensitivity was re-examined and subject blood pressure was followed up. Blood pressure changes in salt-sensitive teenagers were compared to that of non-salt sensitive teenagers over five years.Results After 5 years, the repetition rate of salt sensitivity determined by intravenous saline loading is 92.7%. In teenagers with salt sensitivity on the baseline, both the systolic blood pressure increments and increment rates were much higher than non-salt sensitive teenagers (12.7±12.1 mmHg vs. 2.8±5.2 mmHg, P＜ 0.01; 12.2%± 12.0% vs. 2.5% ±4.4%, P＜ 0.001,respectively). There was a similar trend for diastolic blood pressure (8.4 ± 6.4 mmHg vs. 3.7 ± 6.4 mmHg, P = 0.052; 13.2% ±10.6 % vs. 6.8%± 10.1%, P = 0.053, respectively).Conclusions Salt sensitivity determined by intravenous saline loading showed good reproducibility. Blood pressure increments with age were much higher in salt-sensitive teenagers than non-salt sensitive teenagers, especially in terms of systolic blood pressure.     

安心颗粒对急诊经皮冠状动脉介入术后生活质量影响的研究

目的：评价使用安心颗粒对急诊经皮冠状动脉介入术（PPCI）术后生活质量的影响.方法：将160例接受PPCI的急性ST段抬高型心肌梗死患者随机分为安心颗粒组（术前顿服安心颗粒8.8g,术后安心颗粒4.4 g/次,每日2次）和对照组（仅接受基础药物治疗）.所有患者均服用阿司匹林、氯吡格雷和阿托伐他汀.分别在入院时、出院前1d、出院后180 d时,应用心肌梗死多维度量表（MIDAS）、中文版SF-36评价量表对患者生活质量评分.并观察术后30 d以内的出血并发症、血小板减少症发生情况.结果：入院时和出院前1d,两组患者的心肌梗死MIDAS、SF-36量表评分比较无差异（P＞0.05）;出院后180 d时,与对照组比较,安心颗粒组MIDAS、SF-36评分明显减低（P＜0.05）;组内与入院时比较,两组出院前1d、出院后180 d时,MIDAS、SF-36评分均降低（P＜0.05）.两组患者在随访期间均无大量出血、少量出血、重度和极重度血小板减少症发生,安心颗粒组有4例、对照组有7例发生不明显出血（P＞0.05）.两组发生轻度血小板减少症的患者数比较无差异（P＞0.05）.结论：PPCI使用安心颗粒,能改善急性ST段抬高型心肌梗死患者的生活质量,且不增加出血风险.     

The comparative studies of the influences of Urapidil and Nicardipine on sino-atrial node function, atrio-ventricular node function and hemodynamics

Objective:To investigate the influences of urapidil and nicardipine on rabbit sinus function,atrio-ventricular node function and hemodynamics.Methods:Thirty-two Angora's rabbits were selected and randomly divided into four groups.U1 group:urapidil 0.25 mg/kg;U2 group:urapidil 0.5 mg/kg;N1 group:nicardipine 10 μg/kg;N2 group:nicardipine 20 μg/kg.All these medicine were administrated within 30 seconds.Measurements were taken before and after the administration of urapidil or nicardipine for the following data:mean blood pressure(MAP),heart rate(HR),sino-atrial conduction time(SACT),maximal sinoatrial recovery time(SNRTmax)corrected sinus node recovery time(CSNRT),index of sinus node recovery time(SNRTI),Wenckebach A-V conduction frequency (WB),and P-R interval.Results:Significant MAP and HR changes were identified in all of the four groups before and after administration of both urapidil and nicardipine.No significant changes could be found in the rest of the parameters.Intergroup analysis showed that SACT and CSNRT of N1 and N2 groups were shorter than those of the U2 group(P＜0.01);the MAP decreased(P＜0.01)and the HR increased drastically(P＜0.01).Conclusions:Neither urapidil(0.25 mg/kg,0.5 mg/kg)nor nicardipine(10μg/kg,20μg/kg)has any significant influence on rabbit sinus function or rabbit atrio-ventricular node function.Nicardipine could be a better choice than urapidil for parafunctional sinus node patients.     

Expression of OPGmRNA and ODFmRNA in the patients of hip fracture due to osteoporosis

Objective：To investigate the gene expression of osteoprotegerin（OPG） and osteoclast differentiation factor（ODF） in the bone tissue of patients with hip fracture due to osteoporosis. Methods：OPGmRNA and ODFmRNA in the bone tissue in 50 cases of osteoporosis sufferers（over 50 years old） with hip fracture（Observer Group） and 30 cases of hip facture sufferers with no osteoporosis（Control group） were analyzed with the Semi-Quantitative RT-PCR method. Results：The mRNA expressed of ODF, OPG were both high in the patients with hip fracture. In the control group, the expression of OPG mRNA was observed, while the expression of ODF mRNA was very slight. Conclusion：Aged patients contained all signals including OPG, ODF that are essential for inducing osteoclastogenesis and promoting bone resorption.     

The clinicopathological and immuohistochemical analysis of solid-pseudopapillary tumor of the pancreas： report of 9 cases

Objective：To investigate the clinical features, pathological characteristics and immunophenotype of solid-pseudopapillary tumor of the pancreas（SPTP）. Methods：Nine surgically treated cases of SPTP were retrospectively reviewed. Hematoxylin and Eosin（HE） staining and immunohistochemical staining were used to analyze all cases, and the general clinical data was collected. Results：Six patients were asymptomatic except for a palpable mass. Two patients complained of vague-epigastric pain. One patient appeared jaundice. The tumor was encapsulated and solid tissues alternately with cystic tissues. Histologically, the histological structure of solid portion was pseudopapillary with a fibrovascular core. Tumor cells were uniform and medium-sized which were arranged in sheets ets or nests or pseudopapillary patterns. Immunohistochemical studies demonstrated that SPTP proved positive in vimentin（9/9 cases）, AAT（9/9 cases）, NSE（9/9 cases）, ACT（7/9 cases）, CK20（2/9 cases）, CgA（1/9 cases）, S-100（3/gcases）, PR（4/gcases）, Syn（3/9 cases） and CD56（5/9cases）, negative in CEA and ER. Conclusion：SPTP is a tumor predominantly occurring in young women frequently without special symptoms. This tumor has various characteristical histological patterns with different immunophenotype.     

Dynamic Changes in Serum Estradiol and Progesterone levels in Patients of Premenstrual Syndrome with Adverse Flow of Liver-qi

Objective:To probe into the influence of changes of ovarian hormones on the pathogenesis of the specific sub-type premenstrual syndrome(PMS)and reveal partial microcosmic mechanisms of adverse flow of liver-qi.Methods:Estradiol(E2)and progesterone(P)levels in serum were determined at different phases of menstrual cycle by radioimmunoassay.Results:In the group of PMS with adverse flow of liver-qi.the secretive peak value Of E2 and P at the follicular phase significantly decreased,and the secretive peak value at the luteal phase did not come into being.Conclusions:Low E2 and P secretive peak at the follicular phase and absence of secretive peak at the luteal phase is one of the microcosmic mechanisms of PMS with adverse flow of liver-qi.One of the pathophysiologic mechanisms of specific sub-type PMS is probably the continuous low level of E2and P.     

Real-time Three-dimensional Echocardiography in Assessment of Left Ventricular and Right Ventricular Volumes

Real-time three-dimensional echocardiography (RT3DE)is a new ultrasound technique that enables dynamic threedimensional visualization and quantification of the heart in real time. Investigation of feasibility and methodology of RT3DE in determining left ventricular (LV) and right ventricular (RV) volumes, RT3DE was performed in 35 normal adults using Philips SONOS 7500 system with a 2-4 MHz matrix array transducer. The 60°×60° "pyramid" volume database was obtained and analyzed on a TomTec echo workstation. Both LV and RV volumes were calculated with four 3DE methods (i.e. apical 2, 4, 8, and 16-plane) through manually tracing ventricular endocardial borders in end diastole and end systole. Stroke volumes were then calculated. LV volume was also measured by 2DE Simpson's rule using GE VIVID 7 ultrasound machine.     

SCREENING FOR A 21-CHROMOSOME ABNORMALITY IN PREIMPLANTED EMBRYOS OF ELDERLY WOMEN

Increasing maternal age is the only etiological factor unequivocally linked to Down's syndrome in humans. The occurrence rate of newborns with Down's syndrome is about 1/220 in women over 35 years old. However, the occurrence rate in embryos fertilized in vitro, of the elder woman is unclear. Using FISH we screened the number of chromosome 21 in preimplanted embryos of 5 elderly women (average age, 38.4 years) to study the feasibility and necessity of screening trisomy 21 in embryos in patients over 35 years old at the in vitro fertilization (IVF) center.