Imaging vascular function for early stage clinical trials using dynamic contrast-enhanced magnetic resonance imaging

Many therapeutic approaches to cancer affect the tumour vasculature, either indirectly or as a direct target. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) has become an important means of investigating this action, both pre-clinically and in early stage clinical trials. For such trials, it is essential that the measurement process (i.e. image acquisition and analysis) can be performed effectively and with consistency among contributing centres. As the technique continues to develop in order to provide potential improvements in sensitivity and physiological relevance, there is considerable scope for between-centre variation in techniques. A workshop was convened by the Imaging Committee of the Experimental Cancer Medicine Centres (ECMC) to review the current status of DCE-MRI and to provide recommendations on how the technique can best be used for early stage trials. This review and the consequent recommendations are summarised here. Key Points ? Tumour vascular function is key to tumour development and treatment ? Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can assess tumour vascular function ? Thus DCE-MRI with pharmacokinetic models can assess novel treatments ? Many recent developments are advancing the accuracy of and information from DCE-MRI ? Establishing common methodology across multiple centres is challenging and requires accepted guidelines.     

Effects of repetitive multiple freeze-thaw cycles on the biomechanical properties of human flexor digitorum superficialis and flexor pollicis longus tendons

Background

Deep fresh freezing is the most commonly used preservation method for allografts, which is followed by a routine procedure before application—the thawing of the grafts. This work was to explore the biomechanics effects of repetitive freezing–thawing on human tendons.

Methods

Thirty tendons (flexor digitorum superficialis and flexor pollicis longus tendons) were taken from three fresh cadavers. We assigned these tendons into six groups randomly. After the preparation and measurement of cross-sectional area, Fresh Group was tested immediately. The remaining five groups, before biomechanical testing, underwent multiple cycles (1, 2, 3, 5 or 10 cycles) of freezing (− 80 °C for 4 days) and thawing (room temperature for 6 h). Using a material-testing machine, we performed a stress-relaxation test, a creep test and a load to failure test to estimate structural and mechanical properties as well as viscoelastic changes of each group.

Findings

The results of fewer cycles (< 3) of freezing–thawing groups were similar to Fresh Group. The tendons that underwent more than five freezing–thawing cycles demonstrated a significantly smaller ultimate load, stiffness, ultimate stress and Young's modulus. Moreover, the 5 and 10 Cycle Groups showed a significant increase of elongation in creep test and a decrease of load in stress-relaxation test compared with other groups.

Interpretation

Repetitive freezing–thawing (> 5 cycles) declines the structural, mechanical and viscoelastic properties of human tendons. From our results, it is recommended that for deep-frozen preservation of tendon allografts the cycles of freezing–thawing should be less than five times with caution.     

明胶酶与角膜新生血管

目的:着重阐述明胶酶的生理特性和调节以及它在角膜新生血管生成中的作用。资料来源:应用计算机检索PUBMED1990-01/2006-01的相关文章,检索词为“gelatinase,cornea,neovascularization”并限定文章语言种类为English。同时计算机检索CNKI2000-01/2006-01的相关文章,检索词为“明胶酶,角膜,新生血管”,并限定文章语言种类为中文。资料选择:对资料进行初审,并察看每篇文献后的引文。纳入标准:①具有原创性,论点论据可靠的实验文章。②观点明确,分析全面的综述文章。排除标准:重复研究。资料提炼:共收集到30篇符合纳入标准的文献,涉及明胶酶的生理特性、调节,在角膜新生血管中的作用等方面。资料综合:①角膜新生血管形成包括毛细血管内皮下基底膜降解、内皮细胞迁移和增殖、新的血管形成和新的基底膜形成等一系列过程,角膜细胞外基质是参与这个过程的主要成分。②明胶酶是一类参与角膜细胞外基质的分化、黏附、迁移、损伤修复及组织重塑的蛋白水解酶,受基因、酶原、活化后3个水平的调节。③对实验性角膜新生血管发生中明胶酶表达的研究表明,明胶酶是新生血管发生中的重要因子,用明胶酶抑制剂可以抑制新生血管的发生。结论:明胶酶在角膜新生血管发生发展中,发挥着不可替代的作用,通过抑制其活性来阻止角膜新生血管发生,可能成为治疗新生血管相关性角膜疾病的新策略。     

产后早期乳房湿热敷按摩法配合心理暗示对产妇泌乳的影响

目的观察产妇产后早期乳房湿热敷按摩法配合心理暗示疗法对泌乳的影响。方法将300例产妇随机分为对照组144例与观察组156例,对照组产后按常规母乳喂养指导,观察组除常规母乳喂养指导外,于产后6~8 h开始,协助产妇进行乳房湿热敷按摩配合心理暗示疗法,产后进行持续的母乳喂养指导。观察两组平均泌乳时间、乳量及4个月母乳喂养情况。结果观察组较对照组泌乳始动时间明显缩短(均P<0.01),产后1周泌乳量及产后4~6个月母乳喂养率均高于对照组(均P<0.01)。结论产后早期乳房湿热敷配合心理暗示疗法,并进行持续的母乳喂养指导,可促进产妇早期泌乳,增强产妇母乳喂养信心,提高母乳坚持4~6个月以上母乳喂养率,促进母婴身心健康,产生良好的社会效益和经济效益。     

彩色多普勒超声诊断锁骨下动脉窃血综合征

目的探讨彩色多普勒超声对锁骨下动脉窃血综合征的诊断价值。方法应用彩色多普勒超声观测颈动脉、颅内外段椎动脉、锁骨下动脉、无名动脉、基底动脉及大脑后动脉的声像图特征及血流动力学的状况。结果锁骨下动脉窃血综合征主要由动脉粥样硬化和多发性大动脉炎所致,且两种原因在年龄组成、性别分布、好发部位上差异有统计学意义。锁骨下动脉窃血综合征患侧血供的代偿主要来自对侧的椎动脉。结论彩色多普勒超声对绝大多数锁骨下动脉窃血综合征可明确诊断。     

乳腺癌病人心理反应的相关因素及心理干预研究进展

阐述了乳腺癌病人的心理反应与心理社会因素及疾病因素相关，认知疗法、行为疗法、支持一表达式疗法、音乐疗法、教育性干预等心理干预方法对乳腺癌病人有一定的治疗效果。阐明了心理干预在乳腺癌治疗及康复中的重要性.     

超急及急性脑卒中患者三向同性扩散加权像和表观扩散系数的应用

目的:探讨三向同性扩散加权成像和表观扩散系数在早期脑梗死的诊断以及在判断脑梗塞的转归和分期中的应用价值。方法:以2001-06/2005-01暨南大学附属第一医院收治的100例脑梗死患者为观察对象,应用单次激发平面回波三向同性弥散加权成像和常规MRI对100例脑梗死患者共进行140次检查。其中超急性期(<6h)15次,急性期(7～24h)25次,亚急性期(2～7d)34次,稳定期(8～14d)28次,慢性期(15～135d)38次。测定各期病灶平均表观扩散系数值、相对表观扩散系数值及中心-边缘表观扩散系数值。分析各期梗死灶在弥散加权成像、T2WI及表观扩散系数图上的演变情况。结果:100例患者均完成了测试,进入结果分析。①超急性期15例均在弥散加权成像及表观扩散系数图上显示出缺血灶,但其在T2WI上表现正常。②各期病灶表观扩散系数值及在弥散加权成像上信号不同。超急性、急性期脑梗死在弥散加权成像上表现为高信号,其表观扩散系数值较对侧相应区域明显下降[(0.678±0.102)×10-3,(0.960±0.163)×10-3mm2/s,P<0.001]。④超急性、急性期病灶中心相对表观扩散系数最低,从中心往外逐渐升高呈梯度征。⑤超急性、急性期脑梗死灶平均相对表观扩散系数最低,随时间延长由低到高,于8～14d出现假性正常化,于慢性期高于正常水平,相对表观扩散系数与时间具有显著相关(r=0.926,P<0.001)。结论:三向同性弥散加权成像及表观扩散系数图对急性脑梗死,尤其是超急性脑梗死较常规T2WI具有更高的敏感性,能快速、准确地诊断超急性、急性脑梗死。梗死灶表观扩散系数值具有特征性演变规律,结合弥散加权成像及T2WI可以对脑梗死进行分期诊断,对临床个体化治疗有帮助,动态观察可以对疗效进行评价。     

藻酸盐凝胶支架在生物学修复椎间盘退行性变中的应用

目的:藻酸盐凝胶不仅在体外培养细胞使用,还可应用于体内组织工程修复.实验以藻酸盐凝胶为支架复合骨髓间充质干细胞,观察修复兔腰椎间盘退行性变的能力.方法:实验于2006-03/2007-03在解放军第二军医大学长海医院骨科实验室完成.①密度梯度分离法分离培养兔骨髓间充质干细胞,配制1.2% 藻酸钠水溶液,进行体外骨髓间充质干细胞/藻酸盐复合物的制备,观察细胞生长.②18只新西兰大白兔手术建立腰椎间盘退行性变模型,随机分为3组:对照组、空白组和治疗组.在手术建立椎间盘退行性变模型结束时,在治疗组椎间隙,注射干细胞复合藻酸盐凝胶支架, 对照组注射骨髓间充质干细胞,空白组不予任何干预.③应用核磁共振观察椎间盘手术前后高度和T2信号变化;术后12周取材大体观察组织结构;免疫组织化学检测Ⅱ型胶原含量,分光光度法测量蛋白多糖的含量,观察椎间盘退行性变修复效果.结果:18只新西兰大白兔均进入结果分析.①镜下观察支架陷窝内为干细胞,生长良好;将支架行冰冻切片,观察细胞位于网络内,形态良好.②术后12周治疗组MRI测量椎间隙高度和T2信号与术前相比变化最小,与空白组和对照组比较差异有显著性意义(P < 0.05).③术后12周取材大体观察,空白组和对照组的椎间盘,髓核与纤维环不清,中央区域的髓核为纤维组织所替代.而治疗组的椎间盘轻度退行性变,组织结构尚可分清,周围未发现炎症反应,藻酸盐完全降解.④术后12周治疗组蛋白多糖含量高于空白组和对照组(P < 0.05),Ⅱ型胶原含量低于空白组和对照组(P < 0.05).结论:动物实验证实藻酸盐支架复合骨髓间充质干细胞具有修复退行性变椎间盘能力,藻酸盐可以做为修复椎间盘退行性变研究的生物学材料.