Medical application of diffraction enhanced imaging in mouse liver blood vessels

Neovascularization is correlative with many processes of diseases, especially for tumor growth, invasion, and metastasis. What is more, these tumor microvessels are totally different from normal vessels in morphology. Therefore, observation of the morphologic distribution of microvessels is one of the key points for many researchers in the field. Using diffraction enhanced imaging （DEI）, we observed the mirocvessles with diameter of about 40 μm in mouse liver. Moreover, the refraction image obtained from DEI shows higher image contrast and exhibits potential use for medical applications.     

Effects of water exchange on MRI-based determination of relative blood volume using an inversion-prepared gradient echo sequence and a blood pool contrast medium

A prostate tumor model in rats was used to compare histometric parameters of prostate cancer physiology with those obtained by magnetic resonance imaging (MRI). The study was focused on vascular physiology as reflected by relative blood volume v(b). Histometry and MRI showed a significant increase in mean v(b) in tumor compared to normal prostate tissue (histometry: normal tissue v(b)=0.69+/-0.19%, tumor tissue v(b)=1.10+/-0.31%, P<.001; MRI: normal tissue v(b)=0.67+/-0.23%, tumor tissue v(b)=1.77+/-0.67%, P<.001). The experimental work showed that MRI yielded a 60.9+/-0.76% higher v(b) than histometry in tumors, while no significant difference in v(b) was found between both methods in normal prostate tissue. Water exchange is known to affect signal intensity on contrast-enhanced MRI. This article investigated the influence of water exchange between intravascular and extravascular space to account for the discrepancy in the values of v(b) obtained with a dynamic inversion-prepared gradient echo MRI sequence and histometry in tumor and normal prostate tissue. The expected influence of water exchange on v(b) was modeled by a computer simulation of the MRI signal and compared with experimental results measured with MRI and histometry. The simulation was based on a two-compartment model indicating that v(b) may be overestimated by MRI. The magnitude of overestimation leads from 10% for the slow water exchange regime to 70% for fast water exchange. Since slow water exchange is probably predominant and even if the observed histological differences in tumor tissue are considered, an overestimation of only 15% due to water exchange is predicted by the simulation. Therefore the overestimation of tumor blood volume by MRI of 60.9% compared to histometry seems to be attributable to additional causes besides water exchange.     

大鼠的发炎白细胞的喇曼光谱研究

为了研究大鼠处于正常状态和发炎状态下白细胞内部的物质是否发生变化,制备了35%总体表面积Ⅲ度烫伤导致全身炎症的模型,采用一个激发波长为780 nm的半导体激光束来囚禁和激发正常与发炎两种状态下单个白细胞的喇曼光谱.结果显示,正常状态和发炎状态下的白细胞喇曼光谱有显著的区别,主要在726、785、935、1093、1371和1657 cm~(-1)处发炎白细胞的峰值强度比正常白细胞明显高出很多;通过光谱指认表明,当机体发炎时,白细胞中的蛋白质氨基酸含量基本没有变化,但是蛋白质结构发生明显改变;核酸的碱基含量增加,DNA双螺旋结构发生改变.利用PCA主成份对单个白细胞的喇曼光谱进行分析,发现通过PCA可以完全区分出正常状态和发炎状态的白细胞.     

Back‐propagation artificial neural network and attenuated total reflectance‐Fourier transform infrared spectroscopy for diagnosis of basal cell carcinoma by blood sample analysis

A diagnostic method for the cancer, based on investigation of infrared spectra of blood samples, has been developed. The two‐layer modified principal component feed forward back‐propagation artificial neural network (BP‐ANN) was used to classify the attenuated total reflectance‐Fourier transform infrared (ATR‐FTIR) spectra of blood samples obtained from healthy people and those with basal cell carcinoma (BCC). Results showed 98.33% of accuracy, in comparison with the current clinical methods. In the first step, 20 blood samples (10 normal and 10 cancer cases) were applied to construct the calibration model. Spectroscopic studies were performed in 900–1800 cm⁻¹ spectral region with 3.85 cm⁻¹ data space. In order to modify the capability of ANN in prediction of test samples, two different algorithms were applied. The obtained results confirmed the compatibility of the proposed network with the architecture of 20‐8‐2 (input‐hidden‐output) with the pattern model. It was concluded that analysis of blood samples by ATR‐FTIR spectroscopy and ANN chemometric technique would be a reliable approach for detection of BCC. Copyright © 2009 John Wiley & Sons, Ltd.     

Surface‐enhanced Raman scattering spectroscopy for potential noninvasive nasopharyngeal cancer detection

Combining membrane electrophoresis with surface‐enhanced Raman scattering (SERS) spectroscopy, the serum proteins were first purified and then mixed with silver nanoparticles to perform SERS spectral analysis. Therefore, the spectral signatures were enhanced to high‐fidelity SERS signatures because of the purification procedure of the first step. We used the method to analyze blood plasma samples from nasopharyngeal cancer patients (n = 43) and healthy volunteers (n = 33) for cancer detection. Principle component analysis of the SERS spectra revealed that the data points for the cancer group and the normal group form distinct, completely separated clusters with no overlap. Therefore, the nasopharyngeal cancer group can be unambiguously discriminated from the normal group, i.e., with both diagnostic sensitivity and specificity of 100%. These results are very promising for developing a label‐free, noninvasive, and reliable clinical tool for rapid cancer detection and screening. Copyright © 2011 John Wiley & Sons, Ltd.     

Mutual information analysis reveals bigeminy patterns in Andersen-Tawil syndrome and in subjects with a history of sudden cardiac death

Herein we introduce the Mutual Information Function (MIF) as a mathematical method to analyze ventricular bigeminy in certain pathological conditions of the heart known to be associated with frequent ventricular arrhythmias. In particular, we show that the MIF is sensitive enough to detect the bigeminy pattern in symbolic series from patients with Andersen-Tawil syndrome as well as in a group of patients from the Sudden Cardiac Death Holter Databases. The results confirm that MIF is an adequate method to detect the autocorrelation between the appearance of sinus and ventricular premature beats resulting in a bigeminy pattern. It is also shown that MIF reflects the bigeminy patterns as a function of the percentage of ventricular premature beats present in the symbolic series and also as a function of the percentage of bigeminy. The MIF was also useful to establish a consistent difference in the bigeminy pattern related to the diurnal and nocturnal periods presumably associated to the circadian rhythm of the heart. Understanding of the ventricular bigeminy patterns throughout 24-hours could provide some insights into the pathogenesis of ventricular tachyarrhythmias in these pathological conditions.     

Polymer Brushes Showing Non‐Fouling in Blood Plasma Challenge the Currently Accepted Design of Protein Resistant Surfaces

Ultra‐low‐fouling poly[N‐(2‐hydroxypropyl) methacrylamide] (poly(HPMA)) brushes have been synthesized for the first time. Similar to the so far only ultra‐low‐fouling surface, poly(carboxybetaine acrylamide), the level of blood plasma fouling was below the detection limit of surface plasmon resonance (SPR, 0.03 ng · cm⁻²) despite being a hydrogen bond donor and displaying a moderate wettability, thus challenging the currently accepted views for the design of antifouling properties. The antifouling properties were preserved even after two years of storage. To demonstrate the potential of poly(HPMA) brushes for the preparation of bioactive ultra‐low fouling surfaces a label‐free SPR immunosensor for detection of G Streptococcus was prepared.

     

沈阳市20335名0～7岁儿童全血中五种元素含量的分析

为了解沈阳市0～7岁儿童全血铜、锌、钙、镁、铁元素缺乏情况,探讨性别、年龄与5种元素含量之间的关系,对沈阳市20335名0～7岁儿童进行末梢指间采血,用BH5100型原子吸收光谱仪测定了全血中钙、镁、铜、铁、锌的含量。结果表明,儿童血锌平均水平低于正常值范围,缺乏最严重,缺乏率为77．78％;血铜、锌、铁缺乏率与年龄有线性相关关系,且随着年龄的增加呈现下降趋势（P〈0．05）,下降速度在40％～60％之间;全血中5种元素均存在年龄差异（P〈0．01）,血铜元素男童明显高于女童（P〈0．01）。提示儿童应加强膳食干预,提高各种富含微量元素的食物摄人,以促进儿童的生长发育。     

Reflection-mode photoacoustic microscopy using a hollow focused ultrasound transducer for in vivo imaging of blood vessels

A reflection-mode photoacoustic microscope using a hollow focused ultrasound transducer is developed for highresolution in vivo imaging.A confocal structure of the laser and the ultrasound is used to improve the system resolution.The axial and lateral resolutions of the system are measured to be ～ 32 μm and ～ 58 μm,respectively.Ex vivo and in vivo modes are tested to validate the imaging capability of the photoacoustic microscope.The adjacent vein and artery can be seen clearly from the reconstructed photoacoustic images.The results demonstrate that the reflectionmode photoacoustic microscope can be used for high-resolution imaging of micro-blood vessels,which would be of great benefit for monitoring the neovascularization in tumor angiogenesis.     

论无创血糖监测的红外光谱方法(特邀)

介绍了无创血糖监测的几种光学方法以及红外光谱法用于无创血糖监测的优势。分析了无创血糖监测红外光谱法的主要问题,包括光在人体组织中的复杂传播;葡萄糖吸收信号微弱,且与人体中其它生化成分吸收光谱重叠;人体组织背景吸收干扰严重等。总结了无创血糖监测红外光谱法的最新进展,给出抑制人体组织背景吸收干扰的方法,并认为组织液可代替血液用于血糖水平的测量。展望了该领域未来研究趋势,主要涉及精确描述光子在组织中的传输、测量皮肤表皮内或表皮与真皮浅层光谱信息,以及提高光谱仪器信噪比,建立葡萄糖吸收带定标模型。