极低频电磁场生物学效应的细胞和分子生物学研究进展

综述关于极低频电磁场生物学效应的细胞和分子生物学研究结果，包括跨膜信号传递、酶活性、基因表达、细胞增殖、分化和凋亡以及基因突变和染色体畸变等方面。此外，就该领域的研究前号提出了几点看法。     

The effect of low-frequency ultrasound on immersed pig lungs

Acoustic models suggest that high-intensity, low-frequency ultrasound (US) at 21–31 kHz, could cause damage to divers’ lungs. The purpose of the study was to investigate lung tissue changes secondary to water-borne low-frequency US produced by commonly used underwater acoustic beacons (pingers). Explanted pig lungs were immersed and exposed to four different modes of low-frequency US pinger transmission. In each trial, 5 pairs of lungs were exposed to sound and 5 pairs served as controls. One central and one peripheral section were taken from each lung and evaluated microscopically for location and extent of damage. When present, microhaemorrhages were primarily found in a patchy alveolar distribution, as well as in the septal and subpleural regions. Only rare focal microhaemorrhages could be found in the Control Group. The results demonstrate a potential hazard to the immersed lungs of large mammals on exposure to prolonged transmission by commercially available underwater pingers. The relevance of these findings to human exposure should be further evaluated.     

低频超声对卵巢癌细胞的生物学效应

目的　研究低频超声对体外培养的人卵巢癌细胞的急、慢性生物学效应。方法　人卵巢癌细胞 3AO受不同剂量、频率为 0 .2 4MHz超声波辐照 ,根据剂量 -效应曲线确定两种不致细胞急性损伤的声波剂量 ,观察受此两种剂量超声处理后细胞的增殖能力和克隆形成力的变化。结果　 3 .92W /cm2 × 10s和 5 .12W /cm2 × 5s未致细胞急性死亡。受 3 .92W /cm2 × 10s、5 .12W /cm2 × 5s辐照和对照组细胞倍增时间分别为 45 .2h、3 4 .4h和 2 8.6h ,克隆形成率分别为 2 1.3 %、5 0 .3 %和 46.0 % ,受 3 .92W /cm2 × 10s辐照细胞增殖和克隆形成均受到抑制 (P值均 <0 .0 1)。结论　 3AO对超声的敏感性较高 ,超声的迟发效应更决定于辐照持续时间。     

He-Ne激光加速兔骨折愈合的生物学效应及机理探讨

将39只健康雄性新西兰白兔左桡骨人工骨折,利用两种不同剂量(6.24J/cm~2和31.2J/cm~2)的He-Ne激光直接照射骨折区,摄X线平片获取骨愈合信息,平行测定血红细胞浓度、血红蛋白含量、血清碱性磷酸酶活性、血清钙浓度和血清羟脯氨酸浓度5项血液生化指标,并在骨愈合后测定其生物力学性能参数,结果表明:①激光照射使血清钙和血清羟脯氨酸浓度升高,血红细胞浓度降低,②6.24J/cm~2激光照射对血清碱性磷酸酶活性没有影响,而31.2J/cm~2激光照射却抑制了血清碱性磷酸酶活性,③6.24J/cm~2激光照射降低了血红蛋白含量,而31.2J/cm~2激光照射却对血红蛋白含量。没有影响;④生物力学测试表明,愈合骨拉伸性能没有改善,而弯曲性能则有所改善。两种剂量的照射均能促进骨折的愈合,但6.24J/cm~2照射的刺激效应似乎更为明显。     

超声联合微泡对正常兔角膜组织的生物学效应

目的观察不同声强和辐照时间的超声破坏微泡对兔正常角膜组织的生物学效应。方法采用不同声强(0.5W/cm2、1.0W/cm2、2.0W/cm2)和辐照时间(30s、60s、120s)的超声作用于微泡干预的兔眼角膜,并对角膜进行定量分析和病理组织观察。结果超声声强1.0W/cm2、2.0W/cm2与0.5W/cm2组比较,角膜组织损害严重,内皮细胞密度和六角形细胞比例差异有统计学意义(P<0.05);超声辐照时间120s与30s、60s比较,内皮细胞密度和六角形细胞比例有差异有统计学意义(P<0.05)。结论超声联合微泡能明显增强角膜组织的空化效应,且超声能量越大,角膜组织损害越严重。     

Premature cardiac contractions produced efficiently by external high-intensity focused ultrasound

Exposure of myocardium to a mechanical impact may produce premature ventricular contractions (PVCs). High-intensity focused ultrasound was reported to generate PVCs, while microbubbles at the target increased absorption, thus, promoting energy localization and decreased PVC threshold. The objective was to investigate the benefit of a two-stage ultrasonic transmission: (1) asymmetric mostly negative waveform at the focus (microbubbles generation) and (2) asymmetric mostly positive waveform at the microbubbles (impact generation). Optimization of transmission parameters was performed by measuring passive cavitation and attenuation. In vivo intact rat studies were performed while measuring electrocardiograph (ECG) and blood pressure. Most PVCs with blood injection were created while applying 3.06 MPa peak negative pressure during 1 ms, followed by 5.1 MPa peak positive pressure during 50 ms. Increasing the second stage from 5 ms to 50 ms increased the occurrence of PVCs. This study demonstrates that creation of localized microbubble population at the target promotes generation of PVCs without the need to inject contrast agents.     

辐照时间对超声破坏微泡诱导生物效应的影响

目的 探讨不同辐照时间对诊断超声破坏国产超声造影剂全氟显诱导HL-7702的声孔效应、细胞坏死及凋亡的影响.方法 将用于诊断的超声辐照含全氟显微泡的HL-7702细胞悬液,频率2 MHz,MI为1.9,分为对照组及实验组,对照组未经超声辐照,实验组分别设置不同的辐照时间为30 s、1、5、10和20 min.辐照后观察大分子荧光物质进入细胞情况以检测声孔效应,检测细胞活力及凋亡情况.结果 ①荧光染色结果:各实验组与对照组比较差异均具有统计学意义(P<0.05);1 min组与5 min组间及5 min组与10 min组间差异具有统计学意义(P<0.05).而10 min组与20 min组间差异不具有统计学意义(P>0.05).②细胞杀伤结果:与对照组比较,10 min组及20 min组细胞死亡比率差异均具统计学意义(P<0.05).相邻组间比较,5 min组与10 min及10 min组与20 min组间差异具统计学意义(P<0.05).结论 用于诊断的超声破坏全氟显微泡可诱导HL-7702细胞悬液发生声孔效应.随着辐照时间的延长,声孔效应发生率增加.辐照时间延长至10～20 min时,可出现细胞的不可逆性损伤.应用于诊断目的时,高机械指数超声辐照下,辐照时间越短越好,不宜超过5 min;应用于基因或药物的传输时,则选择辐照时间以5 min为佳,必要是可达10 min.     

不同强度超声破坏微泡对犬心肌组织的生物学效应

目的 探讨不同强度的超声破坏微泡对犬心肌组织的生物学效应,优化出影响心肌微环境的最佳辐照条件.方法 9只健康成年杂种犬随机分成3组,每组3只.静脉输入2 ml微泡造影剂,同时采用频率为1 MHz,强度不同的超声辐照(0.5 W/cm2、1.0 W/cm2、2.0 W/cm2)犬心肌组织,辐照时间为5 min.辐照完毕后即刻处死动物,取局部心肌组织.进行病理组织HE染色和透射电镜观察犬心肌细胞及毛细血管内皮细胞等细胞超微结构改变.结果 0.5 W/cm2超声破坏微泡后心肌组织水肿,无出血;1.0 W/cm2超声破坏微泡后心肌组织轻微出血和少量炎症细胞浸润;2.0 W/cm2超声破坏微泡后心肌组织明显出血,炎症细胞一定程度浸润.结论 不同强度超声破坏微泡造影剂能使犬心肌组织产生不同程度的生物学效应;超声强度在1.0～2.0 W/cm2能在使心肌轻度损伤时引起一定程度的炎症反应.     

中药生物效应指纹图谱构建新思路——与微流控芯片技术的结合

随着中药分析手段和信息技术的发展,基于中药化学成分的指纹图谱技术已成为中药质量控制的重要手段之一,但如何更好地快速分析化学指纹图谱,并将其与生物效应指纹图谱在线结合在一定程度上较全面地反映中药质量仍然是中药现代化研究的关键科学问题。本文简单介绍了LC-MS和LC-NMR技术解析化学指纹图谱、微流控芯片技术在生物效应检测中的应用,分析了将微流控芯片技术与化学成分的指纹图谱技术相结合的可能性,希望对我国中药质量研究起到推动和促进作用。     

Linear quadratic modeling of increased late normal-tissue effects in special clinical situations

PURPOSE: To extend linear quadratic theory to allow changes in normal-tissue radiation tolerance after exposure to cytotoxic chemotherapy, after surgery, and in elderly patients. METHODS: Examples of these situations are analyzed by use of the biologic effective dose (BED) concept. Changes in tolerance can be allowed for by: estimation of either the contribution of the additional factor as an equivalent BED or the equivalent dose in 2-Gy fractions or by the degree of radiosensitization by a mean dose-modifying factor (x). RESULTS: The estimated x value is 1.063 (95% confidence limits for the mean, 1.056 to 1.070) for subcutaneous fibrosis after cyclophosphamide, methotrexate, and fluorouracil (CMF) chemotherapy and radiotherapy in breast cancer. The point estimate of x is 1.18 for the additional risk of gastrointestinal late-radiation effects after abdominal surgery in lymphoma patients (or 10.62 Gy at 2 Gy per fraction). For shoulder fibrosis in patients older than 60 years after breast and nodal irradiation, x is estimated to be 1.033 (95% confidence limits for the mean, 1.028 to 1.0385). The equivalent BED values were CMF chemotherapy (6.48 Gy3), surgery (17.73 Gy3), and age (3.61 Gy3). CONCLUSIONS: The LQ model can, in principle, be extended to quantify reduced normal-tissue tolerance in special clinical situations.