Reorganization of gap junctions after focused ultrasound blood�Cbrain barrier opening in the rat brain

Ultrasound-induced opening of the blood–brain barrier (BBB) is an emerging technique for targeted drug delivery to the central nervous system. Gap junctions allow transfer of information between adjacent cells and are responsible for tissue homeostasis. We examined the effect of ultrasound-induced BBB opening on the structure of gap junctions in cortical neurons, expressing Connexin 36, and astrocytes, expressing Connexin 43, after focused 1-MHz ultrasound exposure at 1.25 MPa of one hemisphere together with intravenous microbubble (Optison, Oslo, Norway) application. Quantification of immunofluorescence signals revealed that, compared with noninsonicated hemispheres, small-sized Connexin 43 and 36 gap-junctional plaques were markedly reduced in areas with BBB breakdown after 3 to 6 hours (34.02±6.04% versus 66.49±2.16%, P=0.02 for Connexin 43; 33.80±1.24% versus 36.77±3.43%, P=0.07 for Connexin 36). Complementing this finding, we found significant increases in large-sized gap-junctional plaques (5.76±0.96% versus 1.02±0.84%, P=0.05 for Connexin 43; 5.62±0.22% versus 4.65±0.80%, P=0.02 for Connexin 36). This effect was reversible at 24 hours after ultrasound exposure. Western blot analyses did not show any change in the total connexin amount. These results indicate that ultrasound-induced BBB opening leads to a reorganization of gap-junctional plaques in both neurons and astrocytes. The plaque-size increase may be a cellular response to imbalances in extracellular homeostasis after BBB leakage.     

Delivery of Drugs with Ultrasound

In this article we discuss the potential role of microbubbles, traditionally used as ultrasound contrast agents, for site-specific drug delivery. To reach this goal, microbubbles capable of carrying a drug payload are being developed. To ensure that these microbubbles reach sufficient local concentration at disease sites, specific targeting for diseased tissues can be accomplished using several strategies. These strategies rely on either the intrinsic properties of microbubble shells or conjugation of monoclonal antibodies or other ligands to these shells that recognize antigens expressed in regions of disease. Site-specific delivery of antiinflammatory, antineoplastic, and thrombolytic drugs with microbubbles can be further enhanced by the ability to locally destroy microbubbles within an acoustic field, thereby releasing drugs and improving drug efficacy without systemic adverse effects. In the case of thrombi, ultrasound-mediated microbubble destruction also may facilitate the process of clot lysis. This review also will consider current limitations and technological advances required for the development of this field.     

DSA及CEUS评价颈动脉狭窄程度的探讨

目的:探讨数字减影血管造影(DSA)及超声造影(CEUS)评估颅外段颈动脉狭窄检出率及病变程度的价值.方法:运用常规超声和CEUS对颅外段颈动脉狭窄患者进行显像,判断狭窄的部位及程度,与DSA结果相对比.结果:本组患者经DSA及CEUS检查后发现,CEUS较常规超声明显改善了对血管狭窄的检出,以DSA结果为金标准,常规...     

全反式维甲酸增强携单纯疱疹病毒胸苷酸激酶基因的超声微泡对SMMC-7721细胞的旁观者效应

目的观察经全反式维甲酸(all-trans retinoic acid,ATRA)诱导后,单纯疱疹病毒胸苷酸激酶/丙氧鸟苷系统(HSV-TK/GCV)对人肝癌细胞SMMC-7721旁观者效应的影响。方法免疫组化法观察经全反式维甲酸诱导前后SMMC-7721细胞连接蛋白Cx32的表达;将含有HSV-TK基因的质粒通过静电吸附在脂质微泡表面上,采用超声辐照转染并用倒置显微荧光镜及RT-PCR观察TK基因的转入及表达;MTT法观察经全反式维甲酸诱导后HSV-TK/GCV对肝癌细胞SMMC-7721的旁观者效应。结果经全反式维甲酸诱导后SMMC-7721细胞膜上Cx32表达明显增加,而胞质内仅少量表达;通过超声辐照后HSV-TK基因可顺利转入SMMC-7721细胞中并稳定表达;与对照组相比,经全反式维甲酸诱导组可明显提高HSV-TK/GCV对肝癌细胞SMMC-7721的旁观者效应(P<0.05)。结论全反式维甲酸可提高SMMC-7721细胞中连接蛋白Cx32的表达且能正确定位于细胞膜上,这可能与其能增强HSV-TK/GCV系统对肝癌细胞SMMC-7721的旁观者效应有关。     

脂膜微囊趋向于鼠脑创伤区聚集机制的实验研究

目的研究脂膜微囊向脑损伤位点靶向性聚集的特点，探讨其向鼠脑损伤区靶向性聚集的机制。方法建立脑损伤动物实验模型，制备脂膜微囊悬液。将脑损伤模型建立成功的28只大鼠随机分为以下几组，损伤当日组、伤后24h组、48h组、72h组、7d组、10d组、14d组、21d组、28d组；分别于损伤后不同时间，由尾静脉注射脂膜微囊悬液，鼠脑标本用油红O染色，研究脂膜微囊在脑损伤后的不同时间在损伤灶周围聚集的特点，并采用双重免疫组化染色，研究增生细胞核抗原（PCNA）及胶原纤维酸性蛋白（GFAP）阳性细胞在损伤灶周围分布的特点，讨论其与脂膜微囊靶向性聚集的关系。结果早期即可在损伤灶周围及损伤灶中发现脂膜微囊，且脂膜微囊密度逐渐增加，48h后可在损伤区的周围发现有微囊以丛集方式聚集；在病损10d左右，微囊的密度最大并聚集成环状。损伤后的第2—3周微囊密度下降至一稳定的水平；GFAP，PCNA双重染色发现了它们各自的密度变化曲线，均在损伤后48h达高峰；GFAP阳性细胞的数量及分布范围远较PCNA范围大，且二者均阳性的细胞数量很少。结论脂膜微囊可靶向性聚集于脑损伤位点周围，不同的时间点微囊的密度不同，损伤后第10天其密度达高峰，脂膜微囊靶向性聚集的机制复杂，与血脑屏障破坏引起的血源性细胞渗出有关，也与反应性星形细胞有关。     

超声照射对声振微泡稳定性的影响

目的与方法造影剂微泡浓度、大小是影响心肌声学显影最重要因素。本研究采用２×２×４析因分析法分析不同超声照射条件对造影剂微泡浓度及直径的影响,即声波频率、能量以及照射时间对微泡浓度、大小的单独及交互作用。为临床行静脉心肌声学造影检查时选择适宜的超声照射条件提供参考。结果能量越大、照射时间越长,微泡破坏越多,平均直径越小：照射频率对微泡浓度影响不大,但影响微泡大小,频率越高,微泡越小。结论为减少超声照射对微泡的破坏,提高心肌声学造影效果,应尽可能选用低能量、低频率超声波,并减少不必要的照射时间。     

聚焦超声联合微泡开放血脑屏障增强脑靶向递送研究进展

血脑屏障(blood-brain barrier,BBB)是药物脑靶向递送的最主要屏障,聚焦超声和微泡联合应用为跨BBB脑靶向递送提供了一种新途径,其主要机制为空化效应。本综述概括了近年来采用聚焦超声联合微泡增强BBB通透性实现药物脑靶向递送的相关研究,详细论述了聚焦超声及其作用机制;商品化微泡种类、常用微泡膜材、内核气体和制备方法;聚焦超声联合微泡开放BBB机制及安全性考虑等。聚焦超声联合微泡可能是增强BBB通透性、提高药物脑靶向递送的有效策略,其相关研究可为临床实际应用提供参考。     

Effects of a microbubble ultrasound contrast agent on high-intensity focused ultrasound for uterine fibroids: a randomised controlled trial

Objective: To investigate the effects of a microbubble ultrasound contrast agent on high-intensity focused ultrasound (HIFU) treatment of uterine fibroids.

Methods: A total of 120 patients with solitary uterine fibroid were randomly assigned into Groups A, B, C and D. Patients in Groups A and B received 1.5?ml of SonoVue, Groups C and D received 1.5?ml of saline before HIFU ablation. HIFU sonication started at 6?min after administration of SonoVue or saline in Groups A and C, whereas it started at 10?min in Groups B and D. On day 1 after HIFU, magnetic resonance imaging was performed. Patients were followed up via phone or clinic visit during the first week after HIFU.

Results: No significant difference was observed in terms of age, fibroid location, diameter of fibroids, signal intensity on T2-weighted imaging, or tumour volume among the four groups (p?>?0.05). The use of SonoVue significantly shortened the treatment time and sonication time. The sonication start time of 6?min, relative to 10?min, had significant effects on the treatment time and sonication time. The use of intravenous SonoVue followed by HIFU ablation 6?min later significantly increased the rate of significant grey-scale changes (55.9%) and the non-perfused volume ratio (94.2%?±?10.6%). No significant differences were observed in the incidence of intra-procedure and post-HIFU adverse effects among the four groups (p?>?0.05).

Conclusions: SonoVue could be safely used to enhance the ablation effects of HIFU treatment of uterine fibroids.