偏斜淫羊藿化学成分研究

采用70%乙醇超声波辅助提取偏斜淫羊藿（Epimedium truncatum H.R.Liang）叶片中的类黄酮化学成分,利用LC-MS联用技术鉴定其化合物组成,利用HPLC方法测定其主要活性成分的含量并与药典规定药材箭叶淫羊藿（Epimedium sagittatum）主要活性成分的含量进行比较。结果从偏斜淫羊藿叶片中鉴定出6个化合物：朝藿定B、朝藿定C、淫羊藿苷、3,5,7-三羟基4’-甲氧基-8-异戊烯基黄酮-3-O-α-L-吡喃鼠李糖基（1→2）-α-L-吡喃鼠李糖苷、槲皮素-3-O-鼠李糖甙、山奈苷。该6个化合物均为首次在该植物中发现。偏斜淫羊藿富含朝藿定C,其含量显著高于箭叶淫羊藿主要活性成分的总含量。结果表明LC-MS可以简单、快速地对淫羊藿化学成分进行定性和定量分析,偏斜淫羊藿富含朝藿定C,具有潜在的药用价值。     

超声分子成像：机遇与挑战

随着分子生物学、蛋白组学、基因组学、计算机工程学等学科的不断进步,交叉融合,分子成像逐渐登上历史的舞台,成为研究热点。而超声分子成像随之迅猛发展,近年来超声微泡制备技术的成熟和超声造影检查技术的不断进步,超声造影不再局限获取组织的血流灌注信息,而是逐渐成为特异性的超声分子成像。目前使用超声对比剂研究分子成像和靶向治疗仍处于初级阶段。但是,各种分子成像技术的不断革新和发展,超声分子成像面临着重大的挑战,而在挑战背后同样面临着难逢的机遇。超声医学和分子生物学的迅猛发展,超声分子成像必将成为诊断和治疗疾病的新的手段和方法。超声造影剂仍有许多未能解决的问题,像如何延长微泡的半衰期、如何增强微泡的敏感性和特异性,如何增强目的基因的表达,如何处理组织损伤和高频超声之间的关系等问题,但是如果能解决这些问题,超声造影在现代医学的诊断和治疗中将起到重要的作用。现将超声分子成像综述如下。     

经腹、经阴道与经会阴三种超声途径测量宫颈长度对早产的预测价值

目的:比较经腹、经阴道与经会阴三种超声途径测量宫颈长度对早产的预测价值。方法:选取我院就诊的孕妇780例,根据测量途径不同分为三组,每组260例,分别采用经腹、经阴道与经会阴方法测量宫颈长度。观察并比较三组患者的妊娠结局,以及三种测量方法的敏感度及特异性。结果:三组患者接受率相比,经腹组、经会阴组患者接受率明显高于经阴道组(P0.05);三组患者宫颈显示率相比,经会阴组、经阴道组宫颈显示率显著高于经腹组(P0.05)。经腹组中,宫颈长度2.5 cm的患者早产率为48.46%,明显高于宫颈长度≥2.5 cm的患者早产率17.69%(P0.05);经会阴组中,宫颈长度2.5 cm的患者早产率为37.69%,明显高于宫颈长度≥2.5 cm的患者早产率13.08%(P0.05);经阴道组中,宫颈长度2.5 cm的患者早产率为36.92%,明显高于宫颈长度≥2.5 cm的患者早产率13.46%(P0.05)。结论:三种超声途径测量宫颈长度对预测早产均有很大的临床价值,其中经会阴途径优势更大,值得进一步推广临床使用。     

医学超声治疗原理及其临床应用研究

本文从超声波对人体特有的生物效应出发,用生物医学工程的观点,阐述了现代超声治疗技术基本原理及最新临床应用成果,特别是在超声外科治疗技术中的最新发展,展望了超声治疗技术的应用发展前景。     

Abdominal girth as an index of muscle tension during abdominal hollowing: Selecting the optimal training intensity for the transversus abdominis muscle

The abdominal hollowing technique is used for training the transversus abdominis (TrA). However, the optimal intensity of hollowing is still unclear. The objective of the present study is to verify the validity of estimating the tension of the TrA by measuring the girth of the abdomen with a tape and to determine the optimum intensity of hollowing to effectively train the TrA. Sixteen healthy males performed hollowing with an intensity of 0%, 25%, 50%, 75%, and 100%, estimated from the girth of the abdomen. The shear elastic modulus was measured for the rectus abdominis (RA), external oblique (EO), internal oblique (IO), and TrA at all intensities via ultrasonic shear wave elastography. The shear elastic modulus was considered as the index of the tension of the abdominal muscles at each intensity, and the ratio of the TrA to RA, EO, and IO respectively was calculated as the index of TrA selectivity. As the intensity of hollowing increased, the girth of abdomen decreased and tension of all the four muscles increased. The ratio of TrA to the RA, EO, and IO did not exhibit a significant variation among hollowing intensities of 25% to 100%. It is rational to estimate the tension of the TrA by measuring the girth of the abdomen. Moreover, considering both TrA contraction intensity and selectivity, abdominal hollowing performed at maximum intensity was effective for the maximum contraction training of the TrA.     

Relationship between 22-kHz calls and testosterone in male rats

Ultrasonic calls in rats induced by the presence of a predator, referred to as “22-kHz calls,” are mainly emitted by socially dominant male rats. Testosterone levels are closely related to social dominance in male rats. In the present study, we investigated the relationship between the emission of stress-induced 22-kHz calls and circulating testosterone levels in male rats, using a combination of surgery (castration or sham operation) and chronic steroid administration (testosterone or cholesterol) to modify circulating testosterone levels. We also assessed the effects of androgen and/or estrogen receptor antagonists on the emission of 22-kHz calls in male rats. An air puff stimulus, known to reliably induce 22-kHz calls in rats, was used as a stressor. Castrated rats with cholesterol implants exhibited significantly fewer 22-kHz calls than rats that had received a sham operation and cholesterol implants, and there was no significant difference between castrated rats with testosterone implants and rats that had received a sham operation and cholesterol implants. Only male rats pretreated with a binary mixture of androgen and estrogen antagonists exhibited significantly fewer 22-kHz calls than controls. These results show that testosterone in male rats has a positive effect on the emission of stress-induced 22-kHz calls, and the calls may be regulated by the activation of both androgen and estrogen receptors.     

Seasonal ultrasonic acoustic emissions of <Emphasis Type="Italic">Quercus ilex</Emphasis> L. trees in a Mediterranean forest

Ultrasonic acoustic emissions were measured in Quercus ilex trees of a Mediterranean forest in Catalonia (NE Spain) each season from summer of 2004 to autumn of 2005. Acoustic emissions were maximum during hot and dry summer periods. Acoustic emissions started below 17% soil moisture, 0.85 RWC, and 2.5 MPa leaf water potential. They were negatively correlated with soil moisture and leaf water potential. The relationship between acoustic emissions and leaf water potential was the strongest, indicating that xylem tension is the most important factor inducing both cavitation (acoustic emissions) and a decrease in leaf water potential. Future increase of xylem cavitation derived from climate change may result in growth and survival limitations for this species in the drier southern limits of its current distribution.     

Ultrasound-biophysics mechanisms

Ultrasonic biophysics is the study of mechanisms responsible for how ultrasound and biological materials interact. Ultrasound-induced bioeffect or risk studies focus on issues related to the effects of ultrasound on biological materials. On the other hand, when biological materials affect the ultrasonic wave, this can be viewed as the basis for diagnostic ultrasound. Thus, an understanding of the interaction of ultrasound with tissue provides the scientific basis for image production and risk assessment. Relative to the bioeffect or risk studies, that is, the biophysical mechanisms by which ultrasound affects biological materials, ultrasound-induced bioeffects are generally separated into thermal and non-thermal mechanisms. Ultrasonic dosimetry is concerned with the quantitative determination of ultrasonic energy interaction with biological materials.

Whenever ultrasonic energy is propagated into an attenuating material such as tissue, the amplitude of the wave decreases with distance. This attenuation is due to either absorption or scattering. Absorption is a mechanism that represents that portion of ultrasonic wave that is converted into heat, and scattering can be thought of as that portion of the wave, which changes direction. Because the medium can absorb energy to produce heat, a temperature rise may occur as long as the rate of heat production is greater than the rate of heat removal. Current interest with thermally mediated ultrasound-induced bioeffects has focused on the thermal isoeffect concept. The non-thermal mechanism that has received the most attention is acoustically generated cavitation wherein ultrasonic energy by cavitation bubbles is concentrated. Acoustic cavitation, in a broad sense, refers to ultrasonically induced bubble activity occurring in a biological material that contains pre-existing gaseous inclusions. Cavitation-related mechanisms include radiation force, microstreaming, shock waves, free radicals, microjets and strain. It is more challenging to deduce the causes of mechanical effects in tissues that do not contain gas bodies. These ultrasonic biophysics mechanisms will be discussed in the context of diagnostic ultrasound exposure risk concerns.     

Optimization of ultrasonic-stimulated solvent extraction of sinigrin from Indian mustard seed (Brassica Juncea L.) using response surface methodology

Introduction – Sinigrin, a major glucosinolate present in Indian mustard (Brassica juncea L.) seeds as the precursor of the anticancer compound allyl isothiocyanate, shows a wide range of biological activities. It's necessary to optimize the extraction methods and conditions, in order to improve the extraction productivity and save raw material. Objective – To systemically investigate and optimize the most important factors affected the productivity of sinigrin in the process of extraction using response surface methodology. Methodology – The ranges of three main factors including the ethanol concentration, extraction time and extraction temperature were selected by the one‐factor‐at‐a‐time method. The conditions of ultrasonic‐stimulated extraction of sinigrin from defatted Indian mustard seed powder were optimized by Box‐Behnken design to obtain the maximum productivity. Result – The predicted productivity (3.81%) was obtained using 57% ethanol concentration at 81°C for 60 min, with the coefficient of the model R² > 0.96 (n = 17). The actual productivity (3.84 ± 0.02%) of sinigrin under the optimized condition was increased by 70.67% compared with the result of conventional extraction. Meanwhile, HPLC, UV and IR were applied to examine if there is a difference between the ultrasonic‐stimulated solvent extraction and conventional extraction, and the improvement of productivity of sinigrin depended on the destruction of cell wall caused by the elimination of outer pectinous material was explained by SEM and composition content analysis. Conclusion – The ultrasonic‐stimulated solvent extraction was suggested to be a promising method to improve the productivity of sinigrin. And the results demonstrated that sinigrin productivity may be related to pectinous materials existed in the seeds. Copyright © 2010 John Wiley & Sons, Ltd.