不同强度正弦交变电磁场对大鼠骨密度及骨形态计量学的影响

目的 ：研究50 Hz不同强度正弦交变电磁场（sinusoidal electromagnetic fields,SEMFs）对SD大鼠骨密度和骨形态计量学的影响。方法：将30只雌性SD大鼠随机分为3组：A组（正常对照组）,B组（0.1 m T磁场组）和C组（0.6 m T磁场组）。除对照组外,分别给予各磁场组每日3 h的磁场干预。实验8周后处死大鼠,用双能X线骨密度仪检测各组大鼠全身、股骨及椎体骨密度,并对左侧胫骨及椎体L4分别进行骨组织静态和动态分析评价。结果：与A组相比,B组大鼠全身、股骨和椎体骨密度显著增加;股骨和椎体骨小梁面积百分数、骨小梁数量和骨小梁宽度显著增加,骨小梁分离度明显降低;观察双标记有明显变化。C组骨小梁数目与A组相比差异有统计学意义,其余指标差异均无统计学意义。结论：50 Hz 0.1 m T磁场强度的正弦交变电磁场,能够有效增加大鼠骨密度,改善大鼠的骨组织微结构,促进骨形成。     

时间相干电场的外周神经无损刺激

外周神经电刺激可用于运动康复和慢性神经痛治疗,但目前具有空间选择性的无损刺激仍是一个有待解决的问题。提出一种基于时间相干(TI)电场的外周神经选择性无损电刺激方法,对大鼠坐骨神经进行实验,在其大腿腹侧与背侧皮肤上以平行于神经的方向布置刺激电极,通过相干电场扫描,将TI刺激峰值定位到神经上进行选择性刺激。结果表明,该方法可以在预先不知道神经确切位置的情况下通过扫描得出将刺激电场作用到神经的最佳电参数,从而实现对神经的选择性无损刺激,而且在刺激作用点不变的前提下实现刺激强度的控制。在此基础上研究TI电场对大鼠坐骨神经的刺激阈值I_T,测量固定频差Δf=0.5 Hz(n=12),改变频率f=1～6 kHz与固定f=5 kHz(n=11),改变频差Δf=0.5～10 Hz下的I_T,并将其和等幅kHz电场(n=7)的I_T进行比较。结果表明,等幅kHz电场的I_T显著高于TI电场(P<0.05),而且不同频率f下的I_T也有显著性差异(P<0.05),而不同频差Δf下的I_T却没有显著性差异(P>0.05),说明TI电流对大鼠坐骨神经的I_T受f影响而不受Δf影响,且刺激阈值I_T与频率f成正比关系。     

Heart Fields: Spatial Polarity and Temporal Dynamics

In chick and mouse, heart fields undergo dynamic morphological spatiotemporal changes during heart tube formation. Here, the dynamic change in spatial polarity of such fields is discussed and a new perspective on the heart fields is proposed. The heart progenitor cells delaminate through the primitive streak and migrate in a semicircular trajectory craniolaterally forming the bilateral heart fields as part of the splanchnic mesoderm. They switch their polarity from anteroposterior to mediolateral. The anterior intestinal portal posterior descent inverts the newly formed heart field mediolateral polarity into lateromedial by 125° bending. The heart fields revert back to their original anteroposterior polarity and fuse at the midline forming a semi heart tube by completing their half circle movement. Several names and roles were assigned to different portions of the heart fields: posterior versus anterior, first versus second, and primary versus secondary heart field. The posterior and anterior heart fields define basically physical fields that form the inflow–outflow axis of the heart tube. The first and second heart fields are, in contrast, temporal fields of differentiating cardiomyocytes expressing myosin light chain 2a and undifferentiated and proliferating precardiac mesoderm expressing Isl1 gene, respectively. The two markers present a complementary pattern and are expressed transiently in all myocardial lineages. Thus, Isl1 is not restricted to a portion of the heart field or one of the two heart lineages as has been often assumed. Anat Rec, 297:175–182, 2014. © 2013 Wiley Periodicals, Inc.     

Fathers and Daughters

In this discussion I attempt to link some of Tennes's ideas with those preexisting in psychoanalysis, in particular those of Loewald, Matte-Bianco, and Bion; I also elaborate on some of the connections with modern physics. I believe that by going beyond intersubjectivity, it is important to integrate the transpersonal with the intersubjective so that intuition and intimations remain connected with the psychic reality of other people.     

On the optimal choice of the exposure conditions and the nanoparticle features in magnetic nanoparticle hyperthermia

Purpose: Two points are particularly relevant for the clinical use of magnetic nanoparticle hyperthermia: the optimisation of both the exposure conditions and the magnetic nanoparticle characteristics, and the assessment of the limits of scalability of the treatment. To answer these two points a criterion for the individuation of the magnetic field parameters and of the magnetic nanoparticle features that minimise the therapeutic concentration of nanoparticles to be used in magnetic nanoparticle hyperthermia is developed.

Methods: The proposed criterion is based on the estimation of the levels of heat generation rate, due to the electromagnetic field, to be supplied to both the cancerous and the neighbouring healthy tissues for achieving the therapeutic heating of the tumour with a desired degree of spatial selectivity. These quantities are determined by exploiting the Pennes bioheat transfer model.

Results: The reliability of the criterion has been proven by means of an extensive numerical analysis, performed by considering tumours of spherical shape embedded in tissues of cylindrical shape. Several cases, including tumours of different sizes and position have been considered.

Conclusions: By exploiting the proposed criterion a study of the clinical scalability of the therapeutic approach is presented.     

24例中晚期宫颈癌盆腔四野盒式体外照射临床观察

目的:探讨中晚期宫颈癌盆腔四野盒式照射的临床价值。方法:47例中晚期宫颈癌随机分为2组,治疗组24例,采用盆腔四野(前/后及左/右野)盒式照射,DT46～50Gy,每天一对对穿野照射,每野1Gy,每天2Gy,前后野与左右野剂量权重:1.3～1.5:1。同期后装治疗。对照组23例,采用盆腔前后野对穿照射,DT46～50Gy,每天2野,每野1Gy,两野剂量权重:1:1。同期后装治疗。结果:下消化道、膀胱、腹壁皮肤等急性放射反应有明显统计学差异,而两组近期疗效及血液系统急性放射反应无统计学差异。结论:宫颈癌盆腔四野盒式照射靶区剂量分布均匀,小肠、直肠、膀胱剂量低,放射反应小。     

低频脉冲电磁场治疗骨质疏松症患者的疗效观察

目的 观察低频脉冲电磁场对原发性骨质疏松症的疗效.方法 用低频脉冲电磁场治疗30例骨质疏松症患者,观察患者骨痛的缓解情况、血清骨钙素、β-Ⅰ型胶原羧基前肽水平、骨密度变化情况.结果 患者骨痛缓解率达到57.7%,治疗前后血清骨钙素、β-Ⅰ型胶原羧基前肽水平、骨密度均有显著性差异.结论 低频脉冲电磁场能有效缓解骨质疏松患者的骨痛症状,提高骨密度,是治疗原发性骨质疏松症的有效方法之一.     

鼻咽癌常规放疗中面颈联合野的剂量分布研究

目的分析鼻咽癌常规放疗中面颈联合野的剂量分布图以了解剂量分布上存在的问题。方法采用美国ADAC公司的Pinnacle治疗计划系统对1例鼻咽癌患者(福州分期为T2N0M0Ⅱ期)行双侧面颈联合野和中下颈前切野常规定位,再用CT模拟定位机进行CT扫描,把CT影像传送到Pinnacle治疗计划系统进行图像重建及照射野重建,再进行二维计划剂量运算,从而得到各层的剂量分布曲线。结果100%等剂量曲线仅能全包鼻咽腔和蝶窦底壁;105%等剂量曲线全包口咽和射野内的全部颈段脊髓,110%等剂量曲线包口咽的下部分和颈3、4段部分脊髓;95%和90%等剂量曲线穿过蝶窦和斜坡中央;50%的等剂量曲线与射野各界重叠。两野共线处附近组织位于110%等剂量曲线内,最高剂量达220%。结论面颈联合野剂量分布存在着以下几点缺陷:(1)蝶窦和斜坡均在100%～50%的等剂量曲线之间,故存在颅底和斜坡欠量;(2)口咽部剂量在105%～110%的等剂量曲线之间,为高量区,故放射性咽炎常见;(3)颈段脊髓均位于105%～110%高剂量区,易产生放射性脊髓病;(4)两野共线处出现剂量重叠。     

915 MHz微波电磁辐射对断乳鼠学习记忆能力的影响

目的 研究915 MHz微波电磁辐射对断乳鼠学习记忆能力的影响.方法 雄性Wistar大鼠(50～90 g)全身暴露于不同强度915 MHz微波电磁辐射(0、30、60 V/m),每天暴露2 h,每周暴露5 d,连续暴露6周,通过食饵迷宫试验和水迷宫试验研究915 MHz微波电磁辐射对断乳鼠学习和记忆能力影响.结果 915 MHz微波电磁辐射暴露3和6周时,与假暴露组相比较,暴露组大鼠食饵迷宫训练错误率及总训练用时增加(P＜0.05或P＜0.01);30 V/m微波暴露组总训练用时和错误次数训练次数与暴露前差异无统计学意义,而60 V/m微波暴露组总训练用时比暴露明显延长,训练次数和错误次数增加(P＜0.01);而假暴露组的训练用时则明显缩短(P＜0.01);水迷宫试验总的学习时间延长(P＜0.05).结论 随着915 MHz微波电磁辐射暴露剂量的加大及暴露时间的增加,Wistar大鼠断乳鼠的学习和记忆能力存在一定程度的减退.     

PEMF对OVX-OP大鼠骨组织IL-6表达的影响及意义

目的 观察脉冲电磁场(PEMF)对骨质疏松的治疗作用,从IL-6变化的角度探讨其治疗骨质疏松的机理.方法 6月龄雌性未孕Wistar大鼠40只,按体质量随机分为模型组(OVX)、假手术组(Sham)、PEMF组(PEMF OVX PEMF)、雌激素治疗组(Estrogen OVX E).OVX、PEMF、E组行双侧卵巢切除术,Sham组行假手术.术后第9周开始治疗:E组行苯甲酸雌二醇肌肉注射,0.5mg/kg,1次/2周.PEMF组大鼠暴露于脉冲电磁场治疗,1h·次-1·d-1,OVX、Sham组不予以任何处理,作为对照组.治疗10周后处死各组实验动物,测量腰椎骨密度、椎体的最大载荷.采用免疫组化检测椎体骨组织中IL-6表达情况并以图像分析进行组间比较.结果 IL-6主要表达于成骨细胞、骨细胞.PEMF治疗组IL-6的表达较OVX组明显增强;骨组织结构较OVX明显改善;骨密度、生物力学性能优于对照组.结论 PEMF对OVX-OP大鼠具有明显治疗作用;其治疗作用与IL-6在成骨细胞、骨细胞中的表达减弱密切相关.