In vivo measurements of frequency-dependent attenuation in tumors of the liver

Ultrasonic frequency-dependent attenuation (FDA) coefficients of the liver obtained from selected regions of interest within the liver were determined in 106 individuals, 40 cases presumed normal based on medical histories and 66 with malignant tumors (hepatocellular carcinoma [HCC] or metastatic liver tumor) or benign tumors (hepatic hemangioma, hepatic adenoma, or focal nodular hyperplasia of the liver). All liver tumors were confirmed histopathologically by ultrasonically guided fine-needle biopsy and/or operation. Mean attenuation of normal liver was 0.53 ± 0.03 dB/cm/MHz, 0.29 ± 0.05 dB/cm/MHz in hepatic hemangioma, 0.43 ± 0.05 dB/cm/MHz in HCC, and 0.41 ± 0.12 dB/cm/MHz in metastatic liver tumor. Hepatic adenoma and focal nodular hyperplasia of the liver produced higher values, averaging 0.66 ± 0.09 dB/cm/MHz. This difference between malignant and benign tumors was statistically significant. There was some correlation between the FDA for the hepatic tumor and the histopathology that merits further investigation. © 1994 John Wiley & Sons, Inc.     

外周血有核细胞中t-PA mRNA的表达与脑梗死患者的相关性研究

目的：探讨脑梗死患者与t—PA mRNA表达的关系。方法：用逆转录-PCR（RT—PCR）法检测40例脑梗死患者和40例正常对照者外周血有核细胞中t—PA mRNA的表达。结果：脑梗死患者组外周血有核细胞中t—PA mRNA的表达明显增强，同正常对照组比较差异有显著性（P〈0．01）。结论：外周血有核细胞中t—PA mRNA的表达增强与脑梗死密切相关，可作为脑梗死的辅助诊断指标；并有可能作为脑梗死疗效的动态监测指标。     

胶原蛋白复合硫酸肝素生物支架材料研制及其扫描电镜观察

目的：研制一种新型神经组织工程生物支架：胶原蛋白-硫酸肝素支架材料，用于神经损伤的修复。方法：将注有胶原蛋白-硫酸肝素悬浊液的硅胶管缓慢浸入-180℃液氮中，冷冻干燥，通过显微物镜、扫描电镜扫描观察所制胶原蛋白-硫酸肝素内部孔隙结构排列规律及走行方向，测量孔的大小。结果：制备的胶原蛋白复合硫酸肝素支架材料具有纵行的、平行排列的微管结构，高度仿生神经的内部空间三维结构。结论：胶原蛋白复合硫酸肝素生物支架材料作为新型神经组织工程材料基体，可用于周围神经损伤的修复。     

组织多普勒成像评价妊娠期糖尿病胎儿及婴儿心肌功能变化

目的使用组织多普勒技术来评价妊娠期糖尿病胎儿(产前)及婴儿(产后)的心肌收缩及舒张功能变化。方法选取妊娠期糖尿病58例(每例妊娠过程中进行至少进行3~4次检查,共行173次检查),正常妊娠132例,妊娠期糖尿病产后婴儿35例,正常妊娠产后婴儿35例,使用组织多普勒技术测量上述胎儿及婴儿二、三尖瓣环处心肌运动速度(Ea,Aa,Sa峰)来反映左右心的心肌舒张及收缩功能。结果妊娠期糖尿病胎儿及婴儿二、三尖瓣环的运动速度(Ea,Aa,Sa峰)均低于正常妊娠组。结论妊娠期糖尿病胎儿左右心心肌收缩及舒张功能均有损害,并且这一损害延续到了婴儿期。     

Bioengineered Lungs: A Challenge and An Opportunity

Lung biofabrication is a new tissue engineering and regenerative development aimed at providing organs for potential use in transplantation. Lung biofabrication is based on seeding cells into an acellular organ scaffold and on culturing them in an especial purpose bioreactor. The acellular lung scaffold is obtained by decellularizing a non-transplantable donor lung by means of conventional procedures based on application of physical, enzymatic and detergent agents. To avoid immune recipient's rejection of the transplanted bioengineered lung, autologous bone marrow/adipose tissue-derived mesenchymal stem cells, lung progenitor cells or induced pluripotent stem cells are used for biofabricating the bioengineered lung. The bioreactor applies circulatory perfusion and mechanical ventilation with physiological parameters to the lung during biofabrication. These physical stimuli to the organ are translated into the stem cell local microenvironment – e.g. shear stress and cyclic stretch – so that cells sense the physiological conditions in normally functioning mature lungs. After seminal proof of concept in a rodent model was published in 2010, the hypothesis that lungs can be biofabricated is accepted and intense research efforts are being devoted to the topic. The current experimental evidence obtained so far in animal tests and in ex vivo human bioengineered lungs suggests that the date of first clinical tests, although not immediate, is coming. Lung bioengineering is a disrupting concept that poses a challenge for improving our basic science knowledge and is also an opportunity for facilitating lung transplantation in future clinical translation.     

Biomechanical Properties of the Pelvic Floor and its Relation to Pelvic Floor Disorders

Pelvic organ prolapse and stress urinary incontinence remain a clinical challenge as they have unclear pathophysiology and suboptimal treatments. These common pelvic floor disorders (PFD) are characterized by the weakening of the pelvic floor supportive tissues that are directly related to their biomechanical properties. Characterizing the biomechanical properties of the pelvic floor tissues has been the focus of recent studies and researchers are using tools that are not always well understood by clinicians. Therefore, the aim of this review is to provide an overview of the most used methods to test the passive biomechanical properties of the human pelvic floor tissues. We also summarize recent findings from studies looking into the passive properties of the pelvic floor in pelvic floor disorders using the ex vivo tensile test and emerging in vivo techniques. Together, these studies provide valuable quantitative information about the different biomechanical properties of the supportive tissues of the pelvic floor under normal and pathological conditions. Results from ex vivo tests provide valuable data that needs to be correlated to the in vivo data and the clinical manifestations of the symptoms of the PFD. As more research is conducted we will obtain an enhanced understanding of the effect of age, PFD, and treatments on the biomechanical properties of the pelvic floor. This information can contribute to better identify individuals at risk, improve clinical diagnosis, and develop new treatments to advance clinical practice.     

厄贝沙坦对2型糖尿病大鼠肾组织中核因子-кB和MMP-9/TIMP-1表达的影响

目的:观察2型糖尿病大鼠模型肾组织中核因子-κB(NF-κB)、基质金属蛋白酶-9(MMP-9)及基质金属蛋白酶组织抑制物-1(TIMP-1)的表达,并探讨血管紧张素Ⅱ受体拮抗剂厄贝沙坦对NF-κB、MMP-9、TIMP-1及肾脏结构与功能的影响。方法:将24只雄性Wistar大鼠随机分成正常对照组(A组)8只、模型组16只,应用高糖高脂加小剂量链脲佐菌素方法制备2型糖尿病大鼠模型,造模成功后模型组再分为糖尿病组(B组)8只和厄贝沙坦治疗组(C组)8只。6周后采用免疫组织化学及RT-PCR法检测各组大鼠肾脏组织中MMP-9、TIMP-1及NF-κBp65 mRNA的表达,观察肾脏结构和功能的变化。结果:(1)B组大鼠肾组织中NF-κB、TIMP-1的表达较A组和C组明显增强,C组表达强度介于A组和B组之间;MMP-9的表达情况则与之相反。(2)与A组和C组相比,B组肾小球基底膜明显增厚,系膜外基质及尿蛋白排泄率明显增多,C组的病理变化则较B组有所减轻。结论:NF-κB、MMP-9、TIMP-1参与了2型糖尿病肾病的发生、发展病理过程。厄贝沙坦通过抑制NF-κB活性、上调MMP-9、下调TIMP-1发挥其降低蛋白尿、延缓肾脏病理改变发生等治疗作用。     

组织速度成像评估特发性肺动脉高压右心室心肌收缩后收缩

目的探讨组织速度成像评估特发性肺动脉高压(IPAH)右室心肌收缩后收缩(PSS)的意义。方法获取26例IPAH患者和25例正常人右室6节段组织速度曲线,测量各节段等容收缩期峰速(VIC)、射血期峰速(VS)、PSS峰速(VPSS)和PSS持续时间(TPSS),计算VPSS与VIC、VS的比值(VPSS/VIC,VPSS/VS)。以VPSS/VIC作为判定主动性与被动性PSS的标准并对其参数进行比较。结果正常人仅少数节段出现生理性PSS,而IPAH各节段均出现病理性PSS。与生理性PSS相比,病理性PSSVPSS、VPSS/VIC、VPSS/VS增大,TPSS延长。与被动性PSS相比,主动性PSSVPSS、VPSS/VS增大,TPSS延长。结论IPAH右室心肌存在病理性PSS,可能与心肌"类缺血"状况有关。生理性和病理性PSS、主动性和被动性PSS差异明显。     

组织多普勒评价室壁肥厚与左室局部及整体舒张功能的关系

目的　应用脉冲组织多普勒( TDI)技术分析左室肥厚( L VH)患者局部室壁厚度、室壁不对称性与左室局部及整体舒张功能间的相关关系。方法　左室肥厚患者4 2例,包括肥厚型心肌病( HCM) 1 6例和高血压性心脏病( HHD)左室肥厚2 6例;正常对照( NC) 2 0例。二维超声测量并计算左室8个节段室壁厚度( r WT)、总厚度( t WT)及室壁不对称指数( CVw) ;TDI测量8个心肌节段的舒张期运动速度比( r E/ A)和等容舒张时间( r IVRT) ;另外分别应用TDI和脉冲波多普勒测量二尖瓣环和二尖瓣口的舒张期参数m E/ A、m IVRT和PVE/ PVE,IVRT作为整体舒张功能指标。结果　( 1 ) L VH者室壁总厚度及其不对称指数、局部等容舒张时间及其舒张不同步性均高于NC组;( 2 )室壁肥厚的程度及其不对称性与左室整体舒张功能相关( r值的绝对值0 .1 8～0 .4 1 ,P<0 .0 5 ) ;( 3 )局部r WT与r E/ A、r IVRT相关( r值- 0 .4 6 ,0 .4 1 ,P<0 .0 5 )。结论　肥厚型心肌病和高血压性心肌肥厚患者的局部室壁肥厚程度与左室局部舒张功能减低及等容舒张期延长有关;左室壁不对称性肥厚通过影响左室局部心肌早期舒张的速度和同步性间接导致左室整体早期充盈异常;TDI技术用于非创伤性评价左室局部及整体舒张功能有一定价值