左侧乳腺癌根治术后调强放疗中剂量累加的研究

目的 通过形变配准及刚性配准进行左侧乳腺癌放疗中靶区及危及器官剂量累加的研究,探讨二者受量的变化规律。方法 回顾分析16例女性左侧乳腺癌根治术后患者,靶区包括锁上淋巴结引流区加胸壁,均采用6 MV X射线调强放疗（IMRT）。所有患者均接受定位、二程CT扫描,在定位图像（CT1）上制定放疗计划为Plan1,在二程定位图像（CT2）上制定放疗计划为Plan2。利用Velocity软件将Plan2的剂量进行刚性、形变配准到CT1剂量累加后获得Plan-rigid、Plan-deform。比较4个计划中靶区及危及器官的剂量学差异。结果 CT2比CT1的CTV体积平均缩小6.64%;形变后靶区剂量均匀性指数（HI）提高23.05%,而形变后心脏、左、右肺戴斯相似系数（DSC）均低于形变前（0.94±0.01 vs.0.89±0.05、0.96±0.01 vs.0.91±0.03、0.96±0.01 vs.0.92±0.03）,且差异均有统计学意义（Z=-3.208、-3.533、-3.535,P<0.05）;心脏及左肺各剂量-体积指标在Plan2、Plan-rigid、Plan-deform与Plan1的组间差异均无统计学意义（P>0.05）;在Plan-rigid组各剂量-体积指标均高于Plan-deform组。结论 靶区及危及器官体积、剂量-体积指标变化较小的左乳癌根治术后患者在进行放疗剂量累加时,推荐使用刚性配准,且初次调强计划的剂量-体积指标可基本反映双肺及心脏的受量情况。     

Associations between skin structural and functional changes after loading in healthy aged females at sacral and heel skin: A secondary data analysis

Aim of the studyMechanical loading causes skin occlusion and deformation, which influences structural and functional skin properties. Aims of the study were to measure structural and functional skin parameters after loading at the sacral and heel skin and to describe possible associations.Material and methodsA secondary data analysis based on a clinical trial with n = 15 aged women was conducted. Changes of transepidermal water loss, stratum corneum hydration, epidermal hydration, erythema, temperature, structural stiffness, elastic recovery, elastic function, and mean roughness after 120 min loading were described and compared. Spearman's rho (r_s) was used to estimate possible associations.ResultsLoading caused an increase of transepidermal water loss, stratum corneum and epidermal hydration, erythema and temperature at sacral and heel skin. There was a decrease of median roughness at the heel skin surface (-8.5 (IQR -10.5 to 5.5) μm). Strongest positive associations were observed between changes of elastic function and elastic recovery (r_s = 0.9 at heel and sacral skin) and between changes of epidermal and stratum corneum hydration at both skin areas (r_s = 0.7 at sacral skin and r_s = 0.5 at the heel).ConclusionTwo hours loading on a standard foam mattress leads to skin occlusion at the skin surface and mechanical deformation. Skin occlusion seems primarily to increase temperature, stratum corneum and epidermal hydration that may affect mechanical skin properties. Mechanical deformation seems to be responsible for the erythematous response of the dermal skin layer.     

Ultrasound Imaging of Muscle Contraction of the Tibialis Anterior in Patients with Facioscapulohumeral Dystrophy

A need exists for biomarkers to diagnose, quantify and longitudinally follow facioscapulohumeral muscular dystrophy (FSHD) and many other neuromuscular disorders. Furthermore, the pathophysiological mechanisms leading to muscle weakness in most neuromuscular disorders are not completely understood. Dynamic ultrasound imaging (B-mode image sequences) in combination with speckle tracking is an easy, applicable and patient-friendly imaging tool to visualize and quantify muscle deformation. This dynamic information provides insight in the pathophysiological mechanisms and may help to distinguish the various stages of diseased muscle in FSHD. In this proof-of-principle study, we applied a speckle tracking technique to 2-D ultrasound image sequences to quantify the deformation of the tibialis anterior muscle in patients with FSHD and in healthy controls. The resulting deformation patterns were compared with muscle ultrasound echo intensity analysis (a measure of fat infiltration and dystrophy) and clinical outcome measures. Of the four FSHD patients, two patients had severe peroneal weakness and two patients had mild peroneal weakness on clinical examination. We found a markedly varied muscle deformation pattern between these groups: patients with severe peroneal weakness showed a different motion pattern of the tibialis anterior, with overall less displacement of the central tendon region, while healthy patients showed a non-uniform displacement pattern, with the central aponeurosis showing the largest displacement. Hence, dynamic muscle ultrasound of the tibialis anterior muscle in patients with FSHD revealed a distinctively different tissue deformation pattern among persons with and without tibialis anterior weakness. These findings could clarify the understanding of the pathophysiology of muscle weakness in FSHD patients. In addition, the change in muscle deformation shows good correlation with clinical measures and quantitative muscle ultrasound measurements. In conclusion, dynamic ultrasound in combination with speckle tracking allows the study of the effects of muscle pathology in relation to strength, force transmission and movement generation. Although further research is required, this technique can develop into a biomarker to quantify muscle disease severity.     

Nucleus pulposus deformation in response to lumbar spine lateral flexion: an in vivo MRI investigation

Whilst there are numerous studies examining aspects of sagittal plane motion in the lumbar spine, few consider coronal plane range of motion and there are no in vivo reports of nucleus pulposus (NP) displacement in lateral flexion. This study quantified in vivo NP deformation in response to side flexion in healthy volunteers. Concomitant lateral flexion and axial rotation range were also examined to evaluate the direction and extent of NP deformation. Axial T2- and coronal T1-weighted magnetic resonance images (MRI) were obtained from 21 subjects (mean age, 24.8 years) from L1 to S1 in the neutral and left laterally flexed position. Images were evaluated for intersegmental ranges of lateral flexion and axial rotation. A novel methodology derived linear pixel samples across the width of the disc from T2 images, from which the magnitude and direction of displacement of the NP was determined. This profiling technique represented the relative hydration pattern within the disc. The NP was displaced away from the direction of lateral flexion in 95/105 discs (p < 0.001). The extent of NP displacement was associated strongly with lateral flexion at L2–3 (p < 0.01). The greatest range of lateral flexion occurred at L2–3, L3–4 and L4–5. Small intersegmental ranges of axial rotation occurred at all levels, but were not associated with NP displacement. The direction of NP deformation was highly predictable in laterally flexed healthy lumbar spines; however, the magnitude of displacement was not consistent with the degree of intersegmental lateral flexion or rotation.     

计算机虚拟隆鼻手术系统的研发应用

目的研发可用于隆鼻手术术前设计、手术模拟及假体制作的计算机三维模拟软件系统。方法提取20例单纯隆鼻术求美者手术前后的头部螺旋CT数据。应用DICOM格式数据进行三维重建和图像分割,分析手术前后面部轮廓的变形情况,建立数学模型。应用三维数字建模方法和软组织虚拟变形技术,开发计算机三维虚拟隆鼻手术系统。使用此系统预设隆鼻效果、模拟隆鼻手术,并将获取的植入体参数用于假体模型的制作,应用于实际的临床手术。结果建立了鼻假体与鼻外形改变之间关系的数学模型,经过20例隆鼻实例数据的校验,证明具有很高的精度。结论本课题组研发的Pureplastic虚拟整形系统,能够完成隆鼻手术的术前设计及术后效果模拟,并提供植入体参数用于假体制作,证实了计算机技术辅助隆鼻术的可行性。     

血液流变学与急性肺损伤

急性肺损伤(ALI)是指机体遭受严重感染、创伤、休克、化学毒物等打击后出现的以弥漫性毛细血管膜和肺泡损伤为基本病理基础,以肺部炎性细胞浸润、水肿、气体交换障碍为临床特征的一组综合征;其最严重结局或终末阶段即为急性呼吸窘迫综合征(ARDS),死亡率甚高,据多数文献报道约为50%。大量研究表明,ALI/ARDS是一种由各种始动事件引起的全身性急性炎症反应,肺循环障碍为其主要的病理基础,氧化应激则在启动此一病理进程中起重要作用。近十余年,随着生物物理学的研究进展,血液流变学也取得长足进步,已从宏观血液流变学向微观血液流变学发展,开始由细胞水平逐渐深入到亚细胞、分子层面,血液流变学新的理论和技术为循环功能的深入探索提供了重要工具,也将大大加深对ALI/ARDS与肺循环障碍内在联系的认识深度。现将血液流变学进展在ALI/ARDS研究中的应用问题作一综述,以供今后研究和临床工作参考。     

Bilateral preaxial polydactyly: a possible dominant inheritant

We described families with the preaxial polydactyly in bilateral hands and feet. An analysis of their pedigree strongly suggested that the polydactyly was controlled under the autosomal dominant inheritance. Despite multiple abnormalities, surgical outcomes were quite satisfactory. These cases would be useful for antenatal diagnoses and counseling.     

Microrheology and light transmission of blood

Summary The well known flow dependence of the optical density of whole blood was studied by measuring light transmission of blood in viscometric flow. A cone-plate chamber (3° cone angle) was transilluminated (=500–800 nm) while under shear (0–460 sec^–1). The transmitted light was monitored with a selenium barrier layer photocell and was continuously recorded. In an identical chamber, the microrheological behaviour of the cells in flow was monitored by microphotography and then correlated to photometric events.Light transmission of human blood showed a biphasic behaviour when plotted as a function of shear rate: between 0 and about 60 sec^–1, the light transmission decreases with shear, corresponding to aggregate dispersion. Above 60 sec^–1, an increase of light transmission with shear occurs, corresponding to red cell deformation, alignment, and orientation. Bovine blood, which does not form aggregates, shows minimum light transmission at rest. Light transmission then rises progressively with shear from the very onset of slow flow. Equine blood (equus zebra) which has very strong aggregation shows a progressive decrease of light transmission with shear due to aggregate persistence up to 460 sec^–1. Amphibia blood (rana esculanta) shows very pronounced increase in light transmission at low shear rates, but no progression with shear. The nucleated amphibia erythrocytes are oriented but not deformed in flow. Rigidified cells which neither aggregate nor become oriented in flow show no flow dependent changes in light transmission. It became evident that in all blood samples minimum light transmission was recorded when the cells were dispersed and randomly oriented; both aggregation and orientation produced increased light transmission. These results explain earlier controversies in the literature, they shed doubt on the existence of a tubular pinch effect in whole blood rheology.Supported by grants from the Deutsche Forschungsgemeinschaft     

温度对流场中红细胞取向和变形性的影响

本文首次用激光衍射法研究了温度对流场中红细胞在Ｃ＝０轨道的取向及变形的影响。结果表明：在各种切变率下，温度对红细胞取向和变形影响的规律各自相同，红细胞的取向和变形都存在最佳温度，取向的最佳温度为２７℃，与人工双分子膜的相变温度接近；变形的最佳温度为３７℃与正常体温相同，红细胞的取向和变形与膜的流动有关。     

Assessment of Strain Field in Endothelial Cells Subjected to Uniaxial Deformation of Their Substrate

A stretch chamber has been developed in order to visualize the deformation of cells subjected to controlled uniaxial stretch of their substrate. A rectangular, custom-made, transparent silicone channel is used as a deformable substrate. Bovine aortic endothelial cells are plated at the bottom of the channel whose lateral deformation is controlled by two piezoelectric translators. The system is mounted on the stage of a confocal microscope where three-dimensional (3D) images of the cells can be acquired simultaneously in the three RGB channels. The first channel provides images of 216 nm fluorescent beads embedded in the cytoskeleton (used as internal markers). The second is used to image the shape of the nucleus revealed by live cell nucleic acid staining. The third one provides a transmitted light image of the cell outline. 3D images of the cell are taken before deformation, after uniaxial deformation of the substrate (up to 25%) and after relaxation. Results indicate that: (a) the cell closely follows the deformation imposed by the substrate with no measurable residual strain after relaxation, and (b) there is a clear mechanical coupling between the extracellular matrix and the nucleus, which deforms significantly under the applied substrate stretch. Suggesting that the nucleus can directly sense the mechanical environment of the cell, the latter result has potentially important implications for signal transduction.