• 1 Activation volume of DNA duplex formation. 复制标题 收藏 收藏

    【DNA双链体形成的激活量。】 复制标题 收藏 收藏
    DOI:10.1021/bi963175n 复制DOI
    作者列表:Lin MC,Macgregor RB Jr
    BACKGROUND & AIMS: The denaturation-renaturation thermal hysteresis was used to investigate the kinetics of the helix-coil equilibrium of four 22-base pair homopurine-homopyrimidine duplex oligonucleotides with fractional G x C base pair content (f(G x C)) between 0.14 and 0.5. In 20 mM NaCl and 20 mM Tris-HCl at pH 7.0 and at hydrostatic pressures up to 200 MPa, a two-state bimolecular reaction mechanism adequately described the observed kinetics. At 1 MPa and 47 degrees C, the rate constant for helix formation, k1, increased by a factor of 210, and the reverse rate constant, k(-1), decreased by a factor of 420 upon increasing f(G x C) from 0.14 to 0.5. The activation energies for formation of the duplexes were negative and relatively insensitive to f(G x C). The pressure-induced change in the rate constants is related to the activation volume of the reaction step. Pressure causes k1 to become larger, and the magnitude of the change in k1 with pressure increases the lower the f(G x C) value. Thus, when f(G x C) = 0.14, the activation volume for forward reaction, delta V++(1), equals -20 mL/mol, while when f(G x C) = 0.5, delta V++(1) = -6.7 mL/mol. The rate constant for strand separation, k(-1), decreases at high pressure. The activation volume for this step, delta V++(1), varies from 17 to 1.6 mL/mol when f(G x C) = 0.14 and 0.5, respectively. The delta V for helix formation calculated from the activation parameters changed from -23 mL/mol when f(G x C) = 0.14 to -5.8 mL/mol when f(G x C) = 0.5. From extrapolation, it is estimated that the molar volume change for formation of G x C base pairs in homopurine-homopyrimidine sequences is approximately 0 mL/mol. Parameters calculated from kinetics of other two duplex molecules, when f(G x C) = 0.23 and 0.32, lie between these extremes.

    背景与目标: 变性-复性热滞后作用用于研究四个G-C碱基对含量(f(G x C))在0.14至0.5之间的22个碱基对的高嘌呤-高嘧啶双链体寡核苷酸的螺旋-螺旋平衡动力学。在pH 7.0和最高200 MPa的静水压力下的20 mM NaCl和20 mM Tris-HCl中,两态双分子反应机理充分描述了所观察到的动力学。在1 MPa和47摄氏度时,随着f(G x C)的增加,螺旋形成的速率常数k1增加了210倍,反向速率常数k(-1)减小了420倍。从0.14到0.5。形成双链体的活化能为负,对f(G x C)相对不敏感。速率常数的压力诱导变化与反应步骤的活化体积有关。压力导致k1变大,并且f(G x C)值越低,k1随压力变化的幅度就越大。因此,当f(G x C)= 0.14时,正向反应的活化体积δV(1)等于-20 mL / mol,而当f(G x C)= 0.5时,δV(1)=- 6.7毫升/摩尔。股线分离的速率常数k(-1)在高压下降低。当f(G x C)分别为0.14和0.5时,此步骤的活化体积delta V(1)从17到1.6 mL / mol不等。由活化参数计算的螺旋形成的δV从当f(G×C)= 0.14时的-23mL / mol变为当f(G×C)= 0.5时的-5.8mL / mol。通过外推,估计在高嘌呤-高嘧啶序列中形成G x C碱基对的摩尔体积变化约为0mL / mol。当f(G x C)= 0.23和0.32时,由其他两个双链体分子的动力学计算得出的参数位于这些极端之间。

  • 【胆囊体积的改变不会影响胆囊管阻力。】 复制标题 收藏 收藏
    DOI:10.1001/archsurg.1990.01410160046010 复制DOI
    作者列表:Sharp KW,Ross CB,Tillman VN,Williams LF Jr
    BACKGROUND & AIMS: :To our knowledge, the relationship between gallbladder volume and cystic duct function has not been studied. We hypothesized that changes in gallbladder volume would influence cystic duct resistance. The effect of gallbladder volume changes on cystic duct resistance to both prograde (emptying) and retrograde (filling) steady-state flow was tested in 12 dogs under basal cholecystokinin-stimulated conditions utilizing a multiport catheter with a highly compliant balloon placed within the gallbladder fundus. Gallbladder volume was regulated by varying balloon volume from empty to just beyond physiologic distention. Cystic duct resistance was not affected by balloon volume under basal or stimulated conditions or by the direction of perfusate flow. This study demonstrated no relationship between gallbladder volume and cystic duct resistance and did not demonstrate a cystic duct sphincter mechanism at physiologic gallbladder volumes.
    背景与目标: :据我们所知,尚未研究胆囊体积与胆囊管功能之间的关系。我们假设胆囊体积的变化会影响胆囊管阻力。胆囊体积变化对胆囊管抵抗顺行(空)和逆行(充盈)稳态血流的影响在12条经基础胆囊收缩素刺激的狗中使用多端口导管,并在胆囊内放置高度顺应性球囊进行了测试。胆囊体积的调节是通过将气囊体积从空变到生理上的变化来进行的。囊性导管阻力不受基础或刺激条件下的球囊容积或灌注液流向的影响。这项研究表明胆囊体积和胆囊管阻力之间没有关系,并且在生理胆囊体积上也没有证明胆囊括约肌的机制。
  • 【自发性颅内低血压后小剂量硬膜外补血后的膀胱和肠功能障碍。】 复制标题 收藏 收藏
    DOI:10.1016/j.jocn.2012.02.022 复制DOI
    作者列表:Han IB,Ropper AE,Teng YD,Ryoo YH,Kim O
    BACKGROUND & AIMS: :Epidural blood patch (EBP) is an effective procedure for the treatment of spontaneous intracranial hypotension (SIH). Neurological compromise following EBP, although rare, is recognized as a serious potential complication. We describe a 33-year-old female patient in whom long-term bladder and bowel dysfunction developed following a small volume (10 mL) EBP to treat SIH. We also discuss the possible pathophysiological mechanisms related to this complication in the postprocedure setting.
    背景与目标: :硬膜外补血(EBP)是治疗自发性颅内低血压(SIH)的有效方法。 EBP后的神经功能损害虽然很少见,但被认为是严重的潜在并发症。我们描述了一名33岁的女性患者,在该患者中,小剂量(10 mL)EBP治疗SIH后会出现长期的膀胱和肠功能障碍。我们还将讨论与术后并发症相关的可能的病理生理机制。
  • 【先天性心脏病中的心脏T1定位:用于测量心肌细胞外体积分数的推注与输注方案。】 复制标题 收藏 收藏
    DOI:10.1007/s10554-017-1191-2 复制DOI
    作者列表:Al-Wakeel-Marquard N,Rastin S,Muench F,O H-Ici D,Yilmaz S,Berger F,Kuehne T,Messroghli DR
    BACKGROUND & AIMS: :Myocardial extracellular volume fraction (ECV) reflecting diffuse myocardial fibrosis can be measured with T1 mapping cardiovascular magnetic resonance (CMR) before and after the application of a gadolinium-based extracellular contrast agent. The equilibrium between blood and myocardium contrast concentration required for ECV measurements can be obtained with a primed contrast infusion (equilibrium contrast-CMR). We hypothesized that equilibrium can also be achieved with a single contrast bolus to accurately measure diffuse myocardial fibrosis in patients with congenital heart disease (CHD). Healthy controls (n = 17; median age 24.0 years) and patients with CHD (n = 19; 25.0 years) were prospectively enrolled. Using modified Look-Locker inversion recovery T1 mapping before, 15 min after bolus injection, and during constant infusion of gadolinium-DOTA, T1 values were obtained for blood pool and myocardium of the left ventricle (LV), the interventricular septum (IVS), and the right ventricle (RV) in a single midventricular plane in short axis or in transverse orientation. ECV of LV, IVS and RV by bolus-only and bolus-infusion correlated significantly in CHD patients (r = 0.94, 0.95, and 0.74; p < 0.01, respectively) and healthy controls (r = 0.96, 0.89, and 0.64; p < 0.05, respectively). Bland-Altman plots revealed no significant bias between the techniques for any of the analyzed regions. ECV of LV and RV myocardium measured by bolus-only T1 mapping agrees well with bolus-infusion measurements in patients with CHD. The use of a bolus-only approach facilitates the integration of ECV measurements into existing CMR imaging protocols, allowing for assessment of diffuse myocardial fibrosis in CHD in clinical routine.
    背景与目标: :应用基于g的细胞外造影剂前后,可通过T1映射心血管磁共振(CMR)来测量反映弥漫性心肌纤维化的心肌细胞外体积分数(ECV)。 ECV测量所需的血液和心肌造影剂浓度之间的平衡可通过灌注造影剂(平衡造影剂CMR)获得。我们假设通过单次对比推注也可以达到平衡,以准确测量先天性心脏病(CHD)患者的弥漫性心肌纤维化。前瞻性纳入健康对照组(n = 17);中位年龄24.0岁; CHD患者(n = 19; 25.0岁)。使用改良的Look-Locker反转恢复T1映射,在推注大剂量,之后15分钟以及在持续输注--DOTA期间,获得了左心室(LV),心室间隔(IVS)的血池和心肌的T1值,右心室(RV)在短心轴或横向方向的单个心室中平面内。仅推注和推注输注的LV,IVS和RV的ECV在CHD患者(分别为r = 0.94、0.95和0.74; p <0.01)和健康对照者(r = 0.96、0.89和0.64; p中显着相关)分别<0.05)。布兰德-奥特曼(Bland-Altman)图显示,任何被分析区域的技术之间均无明显偏差。通过仅推注T1测绘测得的LV和RV心肌的ECV与CHD患者的推注量测量非常吻合。仅推注方法的使用有助于将ECV测量值集成到现有的CMR成像协议中,从而可以在临床常规中评估CHD中弥漫性心肌纤维化。
  • 【可以使用囊肿体积来分层with c骨移植重建囊肿缺损后发生并发症的风险吗?】 复制标题 收藏 收藏
    DOI:10.1016/j.jcms.2017.05.010 复制DOI
    作者列表:Safi AF,Grandoch A,Dreiseidler T,Nickenig HJ,Zöller J,Kreppel M
    BACKGROUND & AIMS: INTRODUCTION:The role of the volume of radicular and dentigerous cysts on clinical symptoms is unclear and potentially may predict development of pre- and postoperative complications, especially after cystectomies with large bony defects. Therefore the aim of this study was to assess pre- and postoperative symptoms associated to the volume of jaw cysts. MATERIAL AND METHODS:Retrospective chart review of 111 patients with follicular or dentigerous cysts from 2008-2012. Anterior iliac crest grafts were used to fill defects after cystectomy. χ2-test was performed to analyze associations between two qualitative variables. Binary logistic regression analysis was used as multivariate analysis. P-values p < 0.05 were considered as significant. Volume measurement was performed in a semiautomatic segmentation method with the software "ITK-Snap". RESULTS:Postoperative hypaesthesia correlated significantly with histology (p = 0.025) and localization (p = 0.006). Volume was associated significantly with preoperative hypaesthesia (p = 0.052), postoperative hypaesthesia (p < 0.001), wound healing complications (p < 0.001) and length of wound healing complications (p = 0.001). Multivariate analysis identified volume as independent risk factor for postoperative hypaesthesia (p = 0.015). CONCLUSIONS:Volume analysis appears to be a method that allows risk stratification after surgery of jaw cysts. Therefore we recommend a precise treatment planning with the means of volume analysis to improve therapy outcome of patients with jaw cysts.
    背景与目标: 引言:根管性和牙状囊肿的体积在临床症状上的作用尚不清楚,可能潜在地预测术前和术后并发症的发生,特别是在具有大骨缺损的膀胱切除术之后。因此,本研究的目的是评估与颌骨囊肿体积相关的术前和术后症状。
    材料与方法:回顾性分析2008年至2012年间111例滤泡性或齿状囊肿患者的病历。膀胱切除术后,使用前terior骨移植物填补缺损。进行χ2检验以分析两个定性变量之间的关联。二元逻辑回归分析用作多元分析。 P值p <0.05被认为是显着的。使用软件“ ITK-Snap”以半自动分割方法进行体积测量。
    结果:术后感觉低下与组织学(p = 0.025)和局限性(p = 0.006)显着相关。容量与术前感觉不足(p = 0.052),术后感觉不足(p <0.001),伤口愈合并发症(p <0.001)和伤口愈合并发症的时间(p = 0.001)显着相关。多变量分析确定了体积为术后感觉不足的独立危险因素(p = 0.015)。
    结论:体积分析似乎是一种允许对颌骨囊肿进行手术后进行危险分层的方法。因此,我们建议采用体积分析的方法制定精确的治疗计划,以改善颌骨囊肿患者的治疗效果。
  • 【胸腔镜前路脊柱融合手术后肺体积的变化:三维计算机断层扫描研究。】 复制标题 收藏 收藏
    DOI:10.1097/BRS.0000000000001949 复制DOI
    作者列表:Yu CG,Grant CA,Izatt MT,Labrom RD,Askin GN,Adam CJ,Little JP
    BACKGROUND & AIMS: STUDY DESIGN:Lung volumes and thoracic anatomy were measured from low-dose computed tomography (CT) scans preoperatively and 2 years following thoracoscopic anterior spinal fusion (TASF) for adolescent idiopathic scoliosis (AIS). OBJECTIVE:The aim of this study was to assess changes in lung volume after TASF surgical correction. SUMMARY OF BACKGROUND DATA:AIS patients are known to have decreased pulmonary function as a consequence of their spinal and ribcage deformity. Several studies have evaluated changes in pulmonary function clinically after scoliosis correction surgery showing varied results. To date, there have been no published studies using CT to evaluate lung volume changes following TASF. METHODS:Twenty-three female AIS patients with both pre- and 2 years postoperative low-dose CT scans were selected from an ethically approved, historical databank. Three-dimensional lung volumes were reconstructed to determine anatomical lung volumes. Right and left lung volumes, total lung volume, and right-to-left lung volume ratio were obtained as well as hemithoracic symmetry, to indicate the extent of thorax deformity. Cobb angle, rib hump, levels fused in surgery, and patient height were used for correlation analysis with the lung volume results. RESULTS:Left lung volume, total lung volume, and hemithoracic ratio all increased significantly 2 years after surgery. There was no significant change in right-to-left lung volume ratio (P = 0.36). Statistical regression found significant positive correlation between lung volume changes, reduction in Cobb angle, increase in height, and improvement in hemithoracic symmetry ratio. CONCLUSION:TASF resulted in a statistically significant increase in lung volume following surgery, as well as improvement in the symmetry of the thoracic architecture; however, the postoperative lung volumes remained in the lower 50th percentile relative to females without thoracic deformity. Furthermore, change in lung volume was significantly correlated with changes in Cobb angle, hemithoracic asymmetry, and increased patient height, which are important consequences of thoracic deformity correction surgery. LEVEL OF EVIDENCE:3.
    背景与目标: 研究设计:在术前和胸腔镜前路脊柱融合术(TASF)治疗后的青少年特发性脊柱侧凸(AIS)进行低剂量计算机断层扫描(CT)扫描时,测量肺体积和胸部解剖结构。
    目的:本研究旨在评估TASF手术矫正后肺容量的变化。
    背景数据摘要:已知由于脊柱和胸腔畸形,AIS患者的肺功能下降。多项研究评估了脊柱侧弯矫正手术后临床上肺功能的变化,结果各不相同。迄今为止,还没有发表使用CT评估TASF后肺容量变化的研究。
    方法:从符合道德标准的历史数据库中选择了23例术前和术后2年均进行低剂量CT扫描的女性AIS患者。重建三维肺体积以确定解剖肺体积。获得左右肺体积,总肺体积和左右肺体积比以及半胸对称性,以指示胸廓畸形的程度。将Cobb角,肋骨隆起,手术中的融合水平以及患者身高用于与肺容量结果的相关性分析。
    结果:术后2年,左肺容积,总肺容积和半胸腔比率均显着增加。左右肺体积比无明显变化(P = 0.36)。统计回归发现,肺体积变化,Cobb角减小,身高增加和半胸对称性比率改善之间存在显着正相关。
    结论:TASF导致手术后肺体积显着增加,并改善了胸腔结构的对称性。但是,相对于没有胸椎畸形的女性,术后肺活量仍处于较低的50%。此外,肺容量的变化与Cobb角的变化,半胸廓不对称以及患者身高的增加显着相关,这是胸廓畸形矫正手术的重要结果。
    证据级别:3。
  • 【维生素D减少患有左心室肥大和慢性肾脏病的患者的左心房容量。】 复制标题 收藏 收藏
    DOI:10.1016/j.ahj.2012.09.018 复制DOI
    作者列表:
    BACKGROUND & AIMS: BACKGROUND:Left atrial enlargement, a sensitive integrator of left ventricular diastolic function, is associated with increased cardiovascular morbidity and mortality. Vitamin D is linked to lower cardiovascular morbidity, possibly modifying cardiac structure and function; however, firm evidence is lacking. We assessed the effect of an activated vitamin D analog on left atrial volume index (LAVi) in a post hoc analysis of the PRIMO trial (clinicaltrials.gov: NCT00497146). METHODS AND RESULTS:One hundred ninety-six patients with chronic kidney disease (estimated glomerular filtration rate 15-60 mL/min per 1.73 m(2)), mild to moderate left ventricular hypertrophy, and preserved ejection fraction were randomly assigned to 2 μg of oral paricalcitol or matching placebo for 48 weeks. Two-dimensional echocardiography was obtained at baseline and at 24 and 48 weeks after initiation of therapy. Over the study period, there was a significant decrease in LAVi (-2.79 mL/m(2), 95% CI -4.00 to -1.59 mL/m(2)) in the paricalcitol group compared with the placebo group (-0.70 mL/m(2) [95% CI -1.93 to 0.53 mL/m(2)], P = .002). Paricalcitol also attenuated the rise in levels of brain natriuretic peptide (10.8% in paricalcitol vs 21.3% in placebo, P = .02). For the entire population, the change in brain natriuretic peptide correlated with change in LAVi (r = 0.17, P = .03). CONCLUSIONS:Forty-eight weeks of therapy with an active vitamin D analog reduces LAVi and attenuates the rise of BNP. In a population where only few therapies alter cardiovascular related morbidity and mortality, these post hoc results warrant further confirmation.
    背景与目标: 背景:左心房扩大,左心室舒张功能的敏感积分,与心血管疾病的发病率和死亡率增加有关。维生素D与降低心血管疾病的发病率有关,可能会改变心脏的结构和功能。但是,缺乏确凿的证据。我们在PRIMO试验的事后分析(clinicaltrials.gov:NCT00497146)中评估了活化的维生素D类似物对左心房体积指数(LAVi)的作用。
    方法和结果:196例慢性肾脏疾病(估计肾小球滤过率每1.73 m(2)为15-60 mL / min),轻度至中度左心室肥厚和保留射血分数的患者随机分配为2μg口服paricalcitol或相匹配的安慰剂治疗48周。在治疗开始后的基线以及第24和48周获得了二维超声心动图。在研究期内,与安慰剂组(-0.70 mL)相比,paricalcitol组的LAVi(-2.79 mL / m(2),95%CI -4.00至-1.59 mL / m(2))显着降低。 / m(2)[95%CI -1.93至0.53 mL / m(2)],P = .002)。 Paricalcitol还可以减轻脑钠肽水平的升高(paricalcitol中10.8%,而安慰剂中21.3%,P = .02)。对于整个人群,脑钠肽的变化与LAVi的变化相关(r = 0.17,P = .03)。
    结论:用活性维生素D类似物治疗四十八周可降低LAVi并减轻BNP的升高。在只有少数几种疗法能改变与心血管有关的发病率和死亡率的人群中,这些事后结果值得进一步证实。
  • 【猪模型中胃假瘤的三维三维容积分析。】 复制标题 收藏 收藏
    DOI:10.1016/j.gie.2006.04.034 复制DOI
    作者列表:Vegesna A,Raju R,Asfari W,Korimilli A,Varia A,Orfanidis N,Gaughan J,Ramzan Z,Miller LS
    BACKGROUND & AIMS: BACKGROUND:Tumor burden is difficult to estimate by endoscopy and conventional EUS. OBJECTIVE:The purpose of this study was to determine the accuracy and the reliability of a new 3-dimensional (3D) EUS system in a pseudotumor model (Olympus EUS EXERA EU-M60). DESIGN:A pseudotumor model was developed in a porcine stomach. Pseudotumors were created by injecting various volumes of US gel (0.3, 0.5, 0.7, and 1 mL) into porcine stomach specimens, and then the volume was measured in vitro. Two investigators made volume measurements by outlining the cross-sectional area of the pseudotumor at different radial planes. The instrument then automatically calculated the volume based on the outlined cross-sectional areas. The measured volume was compared with the actual volume of the pseudotumor by using a Bland-Altman analysis. Every second, third, fourth, fifth, sixth, and tenth image was measured to calculate the tumor volume and to determine the optimum number of images required for accurate volume determination. Inter- and intraobserver variability, percentage error, Bland-Altman analysis, analysis of variance (ANOVA), and kappa statistic were performed. SETTING:This study was performed in an in vitro animal model. PATIENTS:There were no patients involved in this study. MAIN OUTCOME MEASUREMENTS:Accuracy and reliability of pseudotumor volume measurement. RESULTS:When averaging across all measurements, the overall average mean error was 3.25%. The overall inter-rater reliability as measured by intraclass correlation coefficient was 0.78. The overall intra-rater reliability as measured by intraclass correlation coefficient was 0.99. Bland-Altman analysis and ANOVA showed similar low variability for measured volumes based on image frequencies for volume calculations between every other and every sixth image but greater variability for measured volumes based on every tenth image. Larger pseudotumors were measured with a slight decrease in mean percentage error. The kappa statistic for interobserver variability was .61, which demonstrated substantial agreement among observers. LIMITATIONS:The major limitation of this technology is the penetration of the US beam to evaluate large tumors, because the US transducer is high frequency (20 MHz) and, therefore, has a limited penetration. CONCLUSIONS:In conclusion, the new Olympus EUS EXERA EU-M60 3D US probe allowed for accurate volume measurements of small pseudotumors in porcine stomach model in vitro. There was substantial evaluator agreement, with a low interobserver variability. Larger pseudotumors were measured with a slightly lower percentage error than smaller pseudotumors. Volumes measured with a greater number of radial images were measured slightly more accurately. We plan to test this device in patients with GI tumors in the near future.
    背景与目标: 背景:难以通过内窥镜检查和常规EUS评估肿瘤负担。
    目的:本研究的目的是确定伪肿瘤模型(Olympus EUS EXERA EU-M60)中新的3维(3D)EUS系统的准确性和可靠性。
    设计:在猪胃中建立了假肿瘤模型。通过将各种体积的US凝胶(0.3、0.5、0.7和1 mL)注入猪胃标本中来创建假瘤,然后在体外进行测量。两名研究人员通过概述假瘤在不同径向平面上的横截面积来进行体积测量。然后,仪器会根据轮廓截面积自动计算体积。通过使用Bland-Altman分析将测得的体积与假瘤的实际体积进行比较。每隔第二,第三,第四,第五,第六和第十个图像进行测量以计算肿瘤体积并确定准确确定体积所需的最佳图像数量。进行了观察者之间和观察者内部的变异性,百分比误差,Bland-Altman分析,方差分析(ANOVA)和kappa统计。
    地点:这项研究是在体外动物模型中进行的。
    患者:本研究无患者参与。
    主要观察指标:假瘤体积测量的准确性和可靠性。
    结果:所有测量结果取平均值时,总体平均平均误差为3.25%。通过类内相关系数测得的整体评分者间可靠性为0.78。通过类别内相关系数测得的整体内部评分者信度为0.99。 Bland-Altman分析和方差分析显示,基于图像频率的测量体积的相似性低变异性,用于每隔一张和每第六张图像之间的体积计算,但基于每十分之一图像的测量体积变异性更大。测量较大的假瘤,平均百分比误差略有降低。观察者间差异的kappa统计值为.61,表明观察者之间存在重大共识。
    局限性:该技术的主要局限性在于US束穿透性大,以评估大型肿瘤,因为US换能器的频率很高(20 MHz),因此穿透性有限。
    结论:总而言之,新的Olympus EUS EXERA EU-M60 3D US探针可在猪胃模型中对小假瘤进行精确的体积测量。评估者之间达成了一致意见,观察者之间的差异很小。与较小的假瘤相比,测量较大的假瘤的百分比误差略低。用更多数量的径向图像测量的体积稍微更精确地测量。我们计划在不久的将来在胃肠道肿瘤患者中测试该设备。
  • 【在自由呼吸的幼儿肺中通过0.3秒电影CT获得的吸气和呼气相位图像上的空气捕获检测。】 复制标题 收藏 收藏
    DOI:10.2214/AJR.05.0895 复制DOI
    作者列表:Goo HW,Kim HJ
    BACKGROUND & AIMS: OBJECTIVE:The objective of our study was to evaluate whether 0.3-second cine CT can be used to detect air trapping in the lungs of young children. SUBJECTS AND METHODS:In 30 children (mean age, 25 months), 0.3-second cine CT was performed at six levels during 3 seconds of quiet breathing. The study population was divided into an air trapping group (n = 24) and a no-air trapping group (n = 6). Lung density was measured at an abnormal area (with or without air trapping) and an adjacent normal area on inspiratory and expiratory phase images. Lung density differences between inspiration and expiration were calculated and compared in abnormal areas (with or without air trapping) and in normal areas. Their percentages were calculated and compared between the two groups. In addition, lung density differences between abnormal and adjacent normal areas were calculated and compared between the two groups. RESULTS:Lung density differences between inspiration and expiration were smaller in areas with air trapping (mean +/- SD, -19 +/- 34 H) than in abnormal areas without air trapping (138 +/- 36 H) (p < 0.001) or in normal areas (111 +/- 49 H) (p < 0.001). Their percentages were smaller in the group with air trapping (-27% +/- 54%) than in the group with no air trapping (120% +/- 87%) (p < 0.001). In the group with air trapping, lung density differences were larger at the expiratory phase (260 +/- 77 H) than at the inspiratory phase (129 +/- 69 H) (p < 0.001), but did not change through the respiratory cycle in the group with no air trapping (p > 0.05). CONCLUSION:Air trapping can be accurately detected in the lungs of free-breathing young children using 0.3-second cine CT.
    背景与目标: 目的:本研究的目的是评估0.3秒的电影CT是否可用于检测年幼儿童肺部的空气滞留情况。
    研究对象和方法:在30名儿童(平均年龄25个月)中,在安静呼吸的3秒内以六个级别进行了0.3秒的电影CT检查。研究人群分为空气诱捕组(n = 24)和无空气诱捕组(n = 6)。在吸气和呼气相位图像上的异常区域(有或没有空气滞留)和相邻的正常区域测量肺密度。计算了吸气和呼气之间的肺密度差异,并在异常区域(有或没有空气滞留)和正常区域中进行了比较。计算他们的百分比,并在两组之间进行比较。此外,计算并比较了正常和邻近正常区域之间的肺密度差异。
    结果:有空气滞留的区域(平均/-SD,-19 /-34 H)的吸气和呼气之间的肺密度差异要小于没有空气滞留的异常区域(138 /-36 H)(p <0.001)或在有空气滞留的区域。正常区域(111 /-49 H)(p <0.001)。有空气滞留组的百分比(-27%/-54%)比没有空气滞留组的百分比(120%/-87%)小(p <0.001)。在有空气滞留的组中,呼气阶段(260 /-77 H)的肺密度差异大于吸气阶段(129 /-69 H)的肺密度差异(p <0.001),但在整个呼吸周期中没有变化。没有空气滞留的组(p> 0.05)。
    结论:使用0.3秒的电影CT可以准确地检测自由呼吸的幼儿的肺部空气捕获。
  • 【平均血小板体积,可预测二尖瓣反流和左心耳血栓形成的严重程度。】 复制标题 收藏 收藏
    DOI:10.1097/MBC.0b013e328364c453 复制DOI
    作者列表:Ulu SM,Ozkeçeci G,Akci O,Ahsen A,Altug A,Demir K,Acartürk G
    BACKGROUND & AIMS: :The incidence of thromboembolism is higher in mitral regurgitation. Mean platelet volume (MPV), which is calculated automatically in the complete blood count tests, indicates platelet production, function and activation. Elevated MPV levels in cardiovascular diseases and some heart valve diseases have been shown before. We aimed to investigate the relationship between MPV and mitral regurgitation, and to evaluate the MPV levels according to the presence of atrial fibrillation or left atrial appendage thrombus in patients with mitral regurgitation for the first time. The study included 57 patients who had undergone transthoracic and transesophageal echocardiography for the classic symptoms and diagnosed with primary (organic) mitral regurgitation. The control group was composed of 46 age, sex and BMI-matched healthy individuals who had undergone transthoracic echocardiography and obtained normal findings. Echocardiographic evaluation was performed according to the recommendations of the American Echocardiography Society. Mean MPV values in patients with mitral regurgitation were significantly higher than the control group (P < 0.001). MPV levels and the thrombus risk were correlated with the severity of the disease. When the patients with mitral regurgitation were classified according to the presence of atrial fibrillation and left atrial appendage thrombus, patients with atrial fibrillation had higher MPV levels compared to patients with normal sinus rhythm (P < 0.001). In addition, highest MPV levels were found in patients with both atrial fibrillation and thrombosis (P < 0.001). In conclusion, measurement of MPV may be considered as a quick and reliable guide in the assessment of mitral regurgitation and thrombus, without any cost or any advanced expensive technology.
    背景与目标: :在二尖瓣关闭不全中血栓栓塞的发生率较高。在全血细胞计数测试中自动计算的平均血小板体积(MPV)表示血小板的产生,功能和激活。以前已经显示出心血管疾病和某些心脏瓣膜疾病中MPV水平升高。我们旨在调查MPV与二尖瓣反流之间的关系,并首次根据二尖瓣反流患者的房颤或左心耳血栓的存在来评估MPV水平。该研究纳入了57例因经典症状接受经胸和经食道超声心动图检查并诊断为原发性(有机)二尖瓣关闭不全的患者。对照组由46名年龄,性别和BMI匹配的健康个体组成,这些个体均接受了经胸超声心动图检查并获得正常结果。超声心动图评估是根据美国超声心动图学会的建议进行的。二尖瓣关闭不全患者的平均MPV值显着高于对照组(P <0.001)。 MPV水平和血栓风险与疾病的严重程度相关。根据房颤和左心耳血栓的存在对二尖瓣返流患者进行分类时,与正常窦性心律患者相比,房颤患者的MPV水平更高(P <0.001)。此外,房颤和血栓形成患者的MPV水平最高(P <0.001)。总之,MPV的测量可被视为评估二尖瓣反流和血栓的快速可靠的指南,而无需任何成本或任何先进的昂贵技术。
  • 【腹腔镜时代减肥手术的量与结局关系。】 复制标题 收藏 收藏
    DOI:10.1007/s00464-013-3112-3 复制DOI
    作者列表:Jafari MD,Jafari F,Young MT,Smith BR,Phalen MJ,Nguyen NT
    BACKGROUND & AIMS: BACKGROUND:The relationship between volume and outcomes in bariatric surgery is well established in the literature. However, the analyses were performed primarily in the open surgery era and in the absence of national accreditation. The recent Metabolic Bariatric Surgery Accreditation and Quality Improvement Program proposed an annual threshold volume of 50 stapling cases. This study aimed to examine the effect of volume and accreditation on surgical outcomes for bariatric surgery in this laparoscopic era. METHODS:The Nationwide Inpatient Sample was used for analysis of the outcomes experienced by morbidly obese patients who underwent an elective laparoscopic stapling bariatric surgical procedure between 2006 and 2010. In this analysis, low-volume centers (LVC < 50 stapling cases/year) were compared with high-volume centers (HVC ≥ 50 stapling cases/year). Multivariate analysis was performed to examine risk-adjusted serious morbidity and in-hospital mortality between the LVCs and HVCs. Additionally, within the HVC group, risk-adjusted outcomes of accredited versus nonaccredited centers were examined. RESULTS:Between 2006 and 2010, 277,760 laparoscopic stapling bariatric procedures were performed, with 85% of the cases managed at HVCs. The mean number of laparoscopic stapling cases managed per year was 17 ± 14 at LVCs and 144 ± 117 at HVCs. The in-hospital mortality was higher at LVCs (0.17%) than at HVCs (0.07%). Multivariate analysis showed that laparoscopic stapling procedures performed at LVCs had higher rates of mortality than those performed at HVCs [odds ratio (OR) 2.5; 95% confidence interval (CI) 1.3-4.8; p < 0.01] as well as higher rates of serious morbidity (OR 1.2; 95% CI 1.1-1.4; p < 0.01). The in-hospital mortality rate at nonaccredited HVCs was 0.22% compared with 0.06% at accredited HVCs. Multivariate analysis showed that nonaccredited centers had higher rates of mortality than accredited centers (OR 3.6; 95% CI 1.5-8.3; p < 0.01) but lower rates of serious morbidity (OR 0.8; 95% CI 0.7-0.9; p < 0.01). CONCLUSION:In this era of laparoscopy, hospitals managing more than 50 laparoscopic stapling cases per year have improved outcomes. However, nonaccredited HVCs have outcomes similar to those of LVCs. Therefore, the impact of accreditation on outcomes may be greater than that of volume.
    背景与目标: 背景:减肥手术的量与结局之间的关系在文献中已得到很好的确立。但是,分析主要是在开放手术时代进行的,并且没有获得国家认可。最近的代谢性减肥手术认证和质量改进计划提出了每年50例吻合钉病例的门槛。这项研究的目的是检查在这个腹腔镜时代减肥和手术对减肥手术效果的影响。
    方法:使用全国住院患者样本分析2006年至2010年间接受选择性腹腔镜吻合钉减肥手术的病态肥胖患者的结局。在该分析中,采用低容量中心(LVC <50例吻合钉/年)与高容量中心相比(HVC≥50例吻合钉病例/年)。进行多变量分析以检查LVC和HVC之间经风险调整的严重发病率和院内死亡率。此外,在HVC组中,对认证中心和非认证中心的风险调整后结果进行了检查。
    结果:2006年至2010年,共进行了277,760例腹腔镜吻合钉减肥手术,其中85%的病例是在HVC进行的。每年接受治疗的腹腔镜吻合钉病例的平均数在LVCs为17±14,而在HVCs为144±117。 LVCs(0.17%)的住院死亡率高于HVCs(0.07%)。多变量分析显示,在LVC处进行的腹腔镜吻合术的死亡率高于在HVC处进行的[死亡率比(OR)2.5; 95%置信区间(CI)1.3-4.8; p <0.01]以及更高的严重发病率(OR 1.2; 95%CI 1.1-1.4; p <0.01)。未经认可的HVC的住院死亡率为0.22%,而获得认可的HVC的住院死亡率为0.06%。多变量分析显示,未经认证的中心的死亡率高于经认证的中心(OR 3.6; 95%CI 1.5-8.3; p <0.01),但较低的严重发病率(OR 0.8; 95%CI 0.7-0.9; p <0.01) 。
    结论:在腹腔镜时代,每年处理超过50例腹腔镜吻合钉病例的医院可改善结局。但是,未经认证的HVC的结果与LVC相似。因此,认证对结果的影响可能大于结果的影响。
  • 【唑来膦酸对下腰痛患者Modic类型和容量的影响。】 复制标题 收藏 收藏
    DOI:10.1186/s12891-017-1632-z 复制DOI
    作者列表:Koivisto K,Järvinen J,Karppinen J,Haapea M,Paananen M,Kyllönen E,Tervonen O,Niinimäki J
    BACKGROUND & AIMS: BACKGROUND:Modic changes (MC) are associated with low back pain (LBP). In this study, we compared changes in size and type of MC, after a single intravenous infusion of 5 mg zoledronic acid (ZA) or placebo, among chronic LBP patients with MC on magnetic resonance imaging (MRI), and evaluated whether the MRI changes correlate with symptoms. METHODS:All patients (N = 19 in ZA, 20 in placebo) had MRI at baseline (0.23-1.5 T) and at one year (1.5-3 T). We evaluated the level, type and volume of all the MC. The MC were classified into M1 (M1 (100%)), predominating M1 (M1/2 (65:35%)) or predominating M2 (M1/2 (35:65%)), and M2 (M2 (100%)). The first two were considered M1-dominant, and the latter two M2-dominant. Volumes of M1 and M2 were calculated separately for the primary MC, which was assumed to cause the symptoms, and the other MC. We analysed the one-year treatment differences in M1 and M2 volumes using analysis of covariance with adjustments for age, sex, body mass index, and smoking. The correlations between the MRI changes and the changes in LBP symptoms were analysed using Pearson correlations. RESULTS:In the ZA group, 84.2% of patients had M1-dominant primary MC at baseline, compared to 50% in the placebo group (p = 0.041). The primary MC in the ZA group converted more likely to M2-dominant (42.1% ZA, 15% placebo; p = 0.0119). The other MC (15 ZA, 8 placebo) were on average 42% smaller and remained largely M2-dominant. The M1 volume of the primary MC decreased in the ZA group, but increased in the placebo group (-0.83 cm3 vs 0.91 cm3; p = 0.21). The adjusted treatment difference for M1 volume was -1.9 cm3 (95% CI -5.0 to 1.2; p = 0.22) and for M2 volume 0.23 cm3 (p = 0.86). In the MC that remained M1-dominant, volume change correlated positively with increased symptoms in the placebo group, whereas the correlations were negative and weak in the ZA group. CONCLUSIONS:Zoledronic acid tended to speed up the conversion of M1-dominant into M2-dominant MC and decrease the volume of M1-dominant MC, although statistical significance was not demonstrated. TRIAL REGISTRATION:The registration number in ClinicalTrials.gov is NCT01330238 and the date of registration February 11, 2011.
    背景与目标: 背景:Modic change(MC)与下背痛(LBP)相关。在这项研究中,我们比较了在接受磁共振成像(MRI)的MC的慢性LBP患者中,单次静脉注射5 mg唑来膦酸(ZA)或安慰剂后MC的大小和类型的变化,并评估了MRI是否改变与症状相关。
    方法:所有患者(ZA中N = 19,安慰剂中20)在基线(0.23-1.5 T)和一年(1.5-3 T)均接受MRI检查。我们评估了所有MC的级别,类型和体积。 MC分为M1(M1(100%)),M1(M1 / 2(65:35%))或M2(M1 / 2(35:65%))以及M2(M2(100%) )。前两个被认为是M1主导,后两个被认为是M2主导。 M1和M2的体积分别针对假定会引起症状的主MC和其他MC进行计算。我们使用年龄,性别,体重指数和吸烟调整的协方差分析,分析了M1和M2量在一年治疗中的差异。使用Pearson相关性分析MRI变化与LBP症状变化之间的相关性。
    结果:在ZA组中,有84.2%的患者在基线时具有M1为主的原发性MC,而在安慰剂组中则为50%(p = 0.041)。 ZA组中的主要MC更有可能转化为M2型(42.1%ZA,15%安慰剂; p = 0.0119)。另一个MC(15 ZA,8个安慰剂)平均缩小了42%,并且仍以M2为主。在ZA组中,主要MC的M1体积减少,但在安慰剂组中增加(-0.83 cm3对0.91 cm3; p = 0.21)。 M1体积的调整后治疗差异为-1.9 cm3(95%CI -5.0至1.2; p = 0.22),M2体积为0.23 cm3(p = 0.86)。在以M1为主的MC中,安慰剂组的体量变化与症状增加呈正相关,而ZA组的相关性为负而微弱。
    结论:唑来膦酸具有加速M1主导型向M2主导型MC转化的作用,并降低M1主导型MC的体积,尽管没有统计学意义。
    试用注册:ClinicalTrials.gov中的注册号为NCT01330238,注册日期为2011年2月11日。
  • 【一种使用基于激光的直接体积测量设备确定固体分数的新颖方法。】 复制标题 收藏 收藏
    DOI:10.3109/10837450.2013.813540 复制DOI
    作者列表:Iyer RM,Hegde S,Singhal D,Malick W
    BACKGROUND & AIMS: :Material properties play a significant role in pharmaceutical processing. In the present study, a novel approach is used to determine solid fraction (SF) based on a direct measurement (DM) of the apparent volume of a sample. The sample was scanned with low intensity laser beams that integrate the sample thickness across the surface (area) and quantitate the apparent volume. The SF by DM method was compared against that obtained by volume displacement (VD) and manual measurement methods. SF was determined by all three methods for formulations of Avicel DG, lactose and a 1:1 mixture of the two. The results from DM method and variability were comparable to that obtained by VD method. The manual method provided lower and more variable results. The DM method was able to differentiate between SF of different ribbon and tablet formulations and at varying force levels. Tracking SF of compacts during tablet development can help in setting acceptable specifications and to understand material deformation behavior during compression. Further, the results of the study indicate that the DM method using laser scan technique was suitable for routine testing of SF of roller compacted ribbons and compressed tablets.
    背景与目标: :材料特性在药物加工中起着重要作用。在本研究中,一种新颖的方法用于基于样品表观体积的直接测量(DM)来确定固体分数(SF)。用低强度激光束扫描样品,该激光束对整个表面(区域)的样品厚度进行积分并确定表观体积。将通过DM方法获得的SF与通过体积位移(VD)和手动测量方法获得的SF进行比较。通过Avicel DG,乳糖和两者的1:1混合物的所有三种方法测定SF。 DM方法和变异性的结果与VD方法可比。手动方法提供的结果更低且更多。 DM方法能够区分不同色带和片剂配方的SF,并以不同的力水平进行区分。在片剂开发过程中跟踪压坯的SF有助于设置可接受的规格并了解压缩过程中的材料变形行为。此外,研究结果表明,使用激光扫描技术的DM方法适用于辊压压实色带和压片的SF的常规测试。
  • 【阿米洛利敏感的Na通道有助于人类神经胶质瘤细胞中调节体积的增加。】 复制标题 收藏 收藏
    DOI:10.1152/ajpcell.00066.2007 复制DOI
    作者列表:Ross SB,Fuller CM,Bubien JK,Benos DJ
    BACKGROUND & AIMS: :Despite intensive research, brain tumors remain among the most difficult type of malignancies to treat, due largely to their diffusely invasive nature and the associated difficulty of adequate surgical resection. To migrate through the brain parenchyma and to proliferate, glioma cells must be capable of significant changes in shape and volume. We have previously reported that glioma cells express an amiloride- and psalmotoxin-sensitive cation conductance that is not found in normal human astrocytes. In the present study, we investigated the potential role of this ion channel to mediate regulatory volume increase in glioma cells. We found that the ability of the cells to volume regulate subsequent to cell shrinkage by hyperosmolar solutions was abolished by both amiloride and psalmotoxin 1. This toxin is thought to be a specific peptide inhibitor of acid-sensing ion channel (ASIC1), a member of the Deg/ENaC superfamily of cation channels. We have previously shown this toxin to be an effective blocker of the glioma cation conductance. Our data suggest that one potential role for this conductance may be to restore cell volume during the cell's progression thorough the cell cycle and while the tumor cell migrates within the interstices of the brain.
    背景与目标: 尽管进行了深入的研究,脑肿瘤仍然是最难治疗的恶性肿瘤之一,这在很大程度上归因于其弥漫性侵袭性和相应的手术切除困难。为了通过脑实质迁移并增殖,神经胶质瘤细胞必须能够在形状和体积上发生显着变化。我们以前曾报道过,神经胶质瘤细胞表达一种在正常人星形胶质细胞中未发现的对阿米洛利和psalmotoxin敏感的阳离子电导。在本研究中,我们调查了该离子通道介导神经胶质瘤细胞调节体积增加的潜在作用。我们发现阿米洛利和psalmotoxin 1都消除了高渗溶液对细胞收缩后细胞体积调节的能力。这种毒素被认为是酸敏感离子通道(ASIC1)的一种特定的肽抑制剂,它是酸敏感离子通道的成员。阳离子通道的Deg / ENaC超家族。我们以前已经证明这种毒素是神经胶质瘤阳离子电导的有效阻断剂。我们的数据表明,这种电导的一个潜在作用可能是在整个细胞周期的细胞进程中以及肿瘤细胞在大脑间隙内迁移的过程中恢复细胞体积。
  • 【肾下主动脉血栓量的测量和决定因素。】 复制标题 收藏 收藏
    DOI:10.1007/s00330-008-0956-3 复制DOI
    作者列表:Golledge J,Wolanski P,Parr A,Buttner P
    BACKGROUND & AIMS: :Intra-luminal thrombus has been suggested to play a role in the progression of abdominal aortic aneurysm (AAA). The aims of this study were twofold. Firstly, to assess the reproducibility of a computer tomography (CT)-based technique for measurement of aortic thrombus volume. Secondly, to examine the determinants of infrarenal aortic thrombus volume in a cohort of patients with aortic dilatation. A consecutive series of 75 patients assessed by CT angiography with maximum aortic diameter > or = 25 mm were recruited. Intra-luminal thrombus volume was measured by a semi-automated workstation protocol based on a previously defined technique to quantitate aortic calcification. Intra- and inter-observer reproducibility were assessed using correlation coefficients, coefficient of variation and Bland-Altman plots. Infrarenal aortic thrombus volume percentage was related to clinical, anatomical and blood characteristics of the patients using univariate and multivariate tests. Infrarenal aortic thrombus volume was related to the severity of aortic dilatation assessed by total aortic volume (r = 0.87, P < 0.0001) or maximum aortic diameter (r = 0.74, P < 0.0001). We therefore examined the clinical determinates of aortic thrombus expressed as a percentage of total aortic volume. Aortic thrombus percentage was negatively correlated with serum high density lipoprotein (HDL, r = -0.31). By ordinal multiple logistic regression analysis serum HDL below median (< or = 1.2 mM: ) was associated with aortic thrombus percentage in the upper quartile adjusting for other risk factors (odds ratio 5.3, 95% CI 1.1-25.0). Infrarenal aortic thrombus volume can be measured reproducibly on CT. Serum HDL, which can be therapeutically raised, may play a role in discouraging aortic thrombus accumulation with implications in terms of delaying progression of AAA.
    背景与目标: 提示腔内血栓在腹主动脉瘤(AAA)的进展中起作用。这项研究的目的是双重的。首先,评估基于计算机断层扫描(CT)的技术在测量主动脉血栓量方面的可重复性。其次,检查一群主动脉扩张患者的肾下主动脉血栓量的决定因素。连续征集了75例经CT血管造影评估为最大主动脉直径≥25 mm的患者。腔内血栓量是通过基于先前定义的定量主动脉钙化的技术的半自动化工作站方案进行测量的。使用相关系数,变异系数和Bland-Altman图评估观察者之间和观察者之间的可重复性。肾下主动脉血栓体积百分比与患者的临床,解剖学和血液特征有关,采用单因素和多因素测试。肾下主动脉血栓量与主动脉扩张的严重程度有关,后者通过总主动脉体积(r = 0.87,P <0.0001)或最大主动脉直径(r = 0.74,P <0.0001)评估。因此,我们检查了主动脉血栓的临床测定值,以总主动脉体积的百分比表示。主动脉血栓百分比与血清高密度脂蛋白呈负相关(HDL,r = -0.31)。通过序数logistic回归分析,血清HDL低于中位数(<或= 1.2 mM:)与上四分位的主动脉血栓百分比相关,并调整了其他危险因素(赔率比5.3,95%CI 1.1-25.0)。肾下主动脉血栓体积可在CT上重复测量。可以治疗性升高的血清HDL可能在阻止主动脉血栓积聚方面起作用,可能会延迟AAA的进展。

+1
+2
100研值 100研值 ¥99课程
检索文献一次
下载文献一次

去下载>

成功解锁2个技能,为你点赞

《SCI写作十大必备语法》
解决你的SCI语法难题!

技能熟练度+1

视频课《玩转文献检索》
让你成为检索达人!

恭喜完成新手挑战

手机微信扫一扫,添加好友领取

免费领《Endnote文献管理工具+教程》

微信扫码, 免费领取

手机登录

获取验证码
登录