旋转磁场治疗激素性股骨头坏死

目的观察旋转磁场对激素性股骨头坏死相关致病环节的抑制作用，探讨其治疗股骨头坏死的机理。方法制备新西兰兔股骨头坏死动物模型，予旋转磁场（由铋铁硼永磁体为磁源的恒定磁场以8Hz频率旋转、在其上方20cm形成直径60cm的半球形磁场、表面强度在0．32～0．60T之间）处理4周（处理1个月组）和8周（处理2个月组），通过X线片和组织切片观察股骨头内部结构变化，检测其血液黏稠度、胆固醇、甘油三脂以及髋关节腔压力等指标的变化，和相应的假处理1个月组、假处理2个月组和空白对照组进行统计学分析比较。结果经旋转磁场处理后，动物模型的股骨头X线片和组织切片均显示其骨小梁形态结构显著改善，同时血液黏稠度、胆固醇、甘油三脂和髋关节腔压力下降均具显著统计学意义（P〈0．01）。结论旋转磁场可以针对股骨头坏死的主要环节，如高脂血症、血液黏稠度增加、关节腔压力增高等多方面发挥调节作用，有效治疗激素性股骨头坏死。     

仿生脉冲电磁场对去卵巢骨质疏松大鼠骨生物力学性能的影响

目的观察仿生脉冲电磁场 (BEMF)对去卵巢大鼠腰椎和股骨生物力学性能的影响。方法 6月龄雌性未孕Wistar大鼠 40只随机分为模型组 (A组 ) ,假手术组 (B组 ) ,BEMF治疗组 (C组 ) ,雌激素治疗组 (D组 )。A组、C组、D组行双侧卵巢切除术 ,B组行假手术。术后 8w ,D组肌肉注射苯甲酸雌二醇 ,0 .5mg/kg ,1次 /2w ;C组暴露于BEMF治疗 ,1h/d ,1次 /d。A组、B组作为对照组。治疗 10w后 ,用CHALLENGER双能X线骨密度测定仪活体测定大鼠腰椎、股骨骨密度后处死各组实验动物 ,取出第 3腰椎、右侧股骨用INSTRON 10 11生物力学测试机测定生物力学指标。结果BEMF治疗后 ,大鼠腰椎、股骨的结构力学 (最大位移、最大载荷、最大能量吸收 )和材料力学 (最大应力、最大应变、弹性系数 )均有改善 (P <0 .0 5 )。结论BEMF可改善去卵巢大鼠腰椎和股骨的生物力学性能 ,增强抗骨折能力。     

维拉帕米在电磁场刺激骨髓间充质干细胞增殖与分化过程中的作用

目的 研究在50Hz、0．8mT的电磁场条件下，维拉帕米（verapamil）对骨髓间充质干细胞增殖与分化的作用，以推断Ca^2＋在此过程中的作用及其内流变化情况。方法 体外培养SD大鼠骨髓间充质干细胞，取第4代细胞，应用工频电磁场及维拉帕米干预，用四甲基偶氮唑蓝比色法检测其增殖活性，按照碱性磷酸酶（ALP）检测试剂盒说明书步骤检测ALP活性，并用改良Gomori钙钻法染色定性观察。结果 50Hz、0．8mT的电磁场对骨髓间充质干细胞具有明显的促增殖（P〈0．01）、抑分化（P〈0．01）作用，但在加入维拉帕米后，这种增殖效应消失而抑分化效应减弱（P〈0．01）。结论 在50Hz、0．8mT的电磁场作用下，骨髓间充质干细胞Ca^2＋内流发生变化，且该变化在骨髓间充质干细胞向成骨方向分化过程中起部分抑制作用，而在促其增殖的过程中起主要作用。     

搅拌槽内新型疏水缔合聚合物AP-P4的溶解性

由于疏水缔合聚合物聚丙烯酰胺(AP-P4)的溶解性差,制约了聚合物驱油技术在海上油田的采收率。考察了温度、矿化度、转速、搅拌器型式及搅拌方式对AP-P4溶解时间和聚合物溶液黏度特性的影响,结果表明：温度与转速的提高有利于聚合物的加速溶解,但不利于聚合物溶液的增黏,存在一个适宜聚合物溶解的最佳矿化度范围;剪切力较小、循环量较大的搅拌器更适合AP-P4的溶解;采用翼型搅拌器向上排出流体,先高转速后低转速的搅拌方式能够加快AP-P4的溶解并获得较高的溶液黏度。     

高强度皮秒脉冲电场对人宫颈癌Hela细胞体外作用初探

目的探讨高强度皮秒脉冲电场对人宫颈癌HeLa细胞的体外损伤效应及机制。方法固定皮秒脉冲电场脉宽800ps、频率3Hz、场强250kV/cm,根据处理脉冲个数不同(0、1 000、3 000和5 000个),将HeLa细胞分为对照组和不同剂量皮秒脉冲处理组,通过MTT比色法检测皮秒脉冲对各组细胞在处理后不同时间点生长抑制的影响;Fluo-3/AM探针标记细胞,激光扫描共聚焦显微镜检测细胞[Ca2+]i改变;Western blot法检测皮秒脉冲电场作用后Bax/Bcl-2蛋白表达量的改变。结果随着脉冲剂量的增加,细胞死亡率上升,生长受到抑制,12h时抑制率最为显著;皮秒脉冲处理可明显升高细胞[Ca2+]i(P<0.05);随着脉冲剂量的增加,细胞内Bax蛋白表达量由对照组的0.205±0.102增加至各处理组的0.257±0.083、0.586±0.138和0.791±0.262(P<0.05);Bcl-2蛋白表达量由对照组的0.694±0.132降低至各处理组的0.591±0.145、0.364±0.105和0.262±0.092(P<0.05);Bax/Bcl-2比值显著上调(P<0.05)。结论高强度皮秒脉冲电场对HeLa细胞有损伤效应,并能诱导其凋亡。     

The M100 component of evoked magnetic fields differs by scaling factors: implications for signal averaging

MEG and EEG studies of event-related responses often involve comparisons of grand averages, requiring homogeneity of the variances. Here, we examine the possibility, implied by the nature of neural sources and the measuring principles involved, that the M100 component of auditory-evoked magnetic fields of different subjects, hemispheres, to different stimuli, and at different sensors differs by scaling factors. Such a multiplicative model predicts a linear increase in the standard deviation with the mean, and thus would have important implications for averaging and comparing such data. Our analyses, at the sensor and the source level, clearly show that the multiplicative model applies. We therefore propose geometric, rather than arithmetic, averaging of the M100 component across subjects and suggest a novel and superior normalization procedure. Our results question the justification of the common practice of subtracting arithmetic grand averages.     

Biophysical stimulation in osteonecrosis of the femoral head

Osteonecrosis of the femoral head is the endpoint of a disease process that results from insufficient blood flow and bone-tissue necrosis, leading to joint instability, collapse of the femoral head, arthritis of the joint, and total hip replacement. Pain is the most frequent clinical symptom. Both bone tissue and cartilage suffer when osteonecrosis of the femoral head develops. Stimulation with pulsed electromagnetic fields (PEMFs) has been shown to be useful for enhancing bone repair and for exerting a chondroprotective effect on articular cartilage. Two Italian studies on the treatment of avascular necrosis of the femoral head with PEMFs were presented in this review. In the first study, 68 patients suffering from avascular necrosis of the femoral head were treated with PEMFs in combination with core decompression and autologous bone grafts. The second one is a retrospective analysis of the results of treatment with PEMFs of 76 hips in 66 patients with osteonecrosis of the femoral head. In both studies clinical information and diagnostic imaging were collected at the beginning of the treatment and at the time of follow up. Statistical analysis was performed using chi-square test. Both authors hypothesize that the short-term effect of PEMF stimulation may be to protect the articular cartilage from the catabolic effect of inflammation and subchondral bone-marrow edema. The long-term effect of PEMF stimulation may be to promote osteogenic activity at the necrotic area and prevent trabecular fracture and subchondral bone collapse. PEMF stimulation represents an important therapeutic opportunity to resolve the Ficat stage-I or II disease or at least to delay the time until joint replacement becomes necessary.     

Bone stimulation for fracture healing: What's all the fuss?

Approximately 10% of the 7.9 million annual fracture patients in the United States experience nonunion and/or delayed unions, which have a substantial economic and quality of life impact. A variety of devices are being marketed under the name of “bone growth stimulators.” This article provides an overview of electrical and electromagnetic stimulation, ultrasound, and extracorporeal shock waves. More research is needed for knowledge of appropriate device configurations, advancement in the field, and encouragement in the initiation of new trials, particularly large multicenter trials and randomized control trials that have standardized device and protocol methods.     

New “biological” meshes: the need for a register. The EHS Registry for Biological Prostheses

Non-absorbable prosthetic materials in hernia surgery can cause relatively rare complications, which include chronic pain, a feeling of stiffness with reduced compliance of the abdominal wall, prosthetic erosion/fistulisation and an increased risk of persistent deep infection. Recently, to avoid these problems, new “biological” prosthetic materials have been developed and proposed for clinical use. These materials are all essentially composed of an extracellular matrix stripped of its cellular components, and differ substantially only in their source (porcine small intestine submucosa, porcine dermis or cadaveric human dermis). Because of the numerous variables involved, it is very difficult to conduct a randomised controlled trial. Therefore, the European Hernia Society (EHS) has decided to start the EHS Registry for Biological Prostheses (ERBP). This is a prospective registry in Europe on the use of collagen meshes in (potentially) contaminated circumstances or clean surgical fields. The registry intends to collect some preoperative data on the patient and indication, intraoperative data and outcome data.     

Random fields—Union intersection tests for detecting functional connectivity in EEG/MEG imaging

Electrophysiological (EEG/MEG) imaging challenges statistics by providing two views of the same underlying spatio‐temporal brain activity: a topographic view (EEG/MEG) and tomographic view (EEG/MEG source reconstructions). It is a common practice that statistical parametric mapping (SPM) for these two situations is developed separately. In particular, assessing statistical significance of functional connectivity is a major challenge in these types of studies. This work introduces statistical tests for assessing simultaneously the significance of spatio‐temporal correlation structure between ERP/ERF components as well as that of their generating sources. We introduce a greatest root statistic as the multivariate test statistic for detecting functional connectivity between two sets of EEG/MEG measurements at a given time instant. We use some new results in random field theory to solve the multiple comparisons problem resulting from the correlated test statistics at each time instant. In general, our approach using the union‐intersection (UI) principle provides a framework for hypothesis testing about any linear combination of sensor data, which allows the analysis of the correlation structure of both topographic and tomographic views. The performance of the proposed method is illustrated with real ERP data obtained from a face recognition experiment. Hum Brain Mapp 2009. © 2009 Wiley‐Liss, Inc.