Liquid-phase microextraction of biomarkers: A review on current methods

The detection and quantification of biomarkers have gained more attention in the medical discipline to evaluating disease progression to manage medical treatment. Biomarkers range from gases to biological macromolecules. Because of the nanomolar range levels of typical biomarkers in plasma, blood, urine, exhalation samples, and other biological fluids as well as complex matrix of biological media, adequate sample preparation methods should be used for quantification of biomarkers. Biomarkers are discussed here generally classified mainly into two subgroups which arisen from disease or exposure compounds. The analytical method is critical for the validity/reliability of a biomarker. Accuracy, precision, reproducibility, recovery, sensitivity, and specificity all have high influence to the consistency with the limit and reference values concerned. In this paper, developments in well-established liquid-phase microextraction techniques for the clinical analysis of biological samples will be reviewed and discussed. This article presents an overview of microextraction methods for biological samples, focusing especially on biomarkers.     

膀胱癌分子标志物基质金属蛋白酶1的可溶性表达和尿液中的活性分析

通过分离人胚胎肾细胞(HEK293)中基质金属蛋白酶1(MMPl)基因序列,利用基因工程技术在大肠杆菌中表达并纯化了包涵体复性的MMP1;采用融合表达硫氧还蛋白(Thioredoxin,TrxA)的方法获得了可溶性的MMPl-TrxA复合蛋白,在TrxA蛋白和MMP1活性中心之间引入了一个肠激酶切割位点,通过酶切作用获得可溶性MMP1.明胶酶谱分析法对体外表达的MMP1和体内(尿液中)MMP1进行了分析比较.结果表明,TrxA蛋白能够显著提高MMP1的可溶性,且可溶性MMP1的明胶降解活性是复性的MMP1降解活性的1.54倍,与尿液中的MMP1的明胶酶降解活性相当.因此,明胶酶谱法是一种有效的、高灵敏的MMP1检测方法,所表达的可溶性MMP1为小分子探针筛选提供了更可靠的分子靶点.     

MICROBE-INPUT CARBOXYLIC BIOMARKERS IN SALINE/HYPERSALINE SEDIMENTS FROM SALINE BASINS OF CHINA*

Carboxylic biomarkers in Saline lake sediments from the Jianghan basin(Hubei Province, China) and the Ejinor hypersaline lake (northern China) are studied. The origin, (?)ransformstion, and psleoecological significances of isoprenoid, triterpenoid and alkenoic acids in the extracted organic matter (EOM) are also discussed.An i-C_(17:6) isoprenoid fatty scid and two C_(31:0) homogammscersnoic fatty acid stereoisomers are detected in psleossline lake sediments. Homogammaceranoic acid might be an important precursor of gammscerane which is abundant in saline sediments. The i-C_(17:6) isoprenoid acid and homogammacersnoic acid might be the lipid components of some halophilic microorganisms such as archaeobacteria halophilus.     

Earlier detection of tumor treatment response using magnetic resonance diffusion imaging with oscillating gradients

An improved method for detecting early changes in tumors in response to treatment, based on a modification of diffusion-weighted magnetic resonance imaging, has been demonstrated in an animal model. Early detection of therapeutic response in tumors is important both clinically and in pre-clinical assessments of novel treatments. Noninvasive imaging methods that can detect and assess tumor response early in the course of treatment, and before frank changes in tumor morphology are evident, are of considerable interest as potential biomarkers of treatment efficacy. Diffusion-weighted magnetic resonance imaging is sensitive to changes in water diffusion rates in tissues that result from structural variations in the local cellular environment, but conventional methods mainly reflect changes in tissue cellularity and do not convey information specific to microstructural variations at sub-cellular scales. We implemented a modified imaging technique using oscillating gradients of the magnetic field for evaluating water diffusion rates over very short spatial scales that are more specific for detecting changes in intracellular structure that may precede changes in cellularity. Results from a study of orthotopic 9L gliomas in rat brains indicate that this method can detect changes as early as 24 h following treatment with 1,3-bis(2-chloroethyl)-1-nitrosourea, when conventional approaches do not find significant effects. These studies suggest that diffusion imaging using oscillating gradients may be used to obtain an earlier indication of treatment efficacy than previous magnetic resonance imaging methods.     

基于核酸适配体的生物标志物检测方法研究进展

核酸适配体是指能与特定靶分子结合的寡核苷酸链。因其具有易修饰、易合成和低免疫原性等特点,作为生物传感器的靶向元件,已广泛应用于各种生物标志物检测技术中。本文综述了近年来基于核酸适配体的生物标志物的检测技术在癌症、心血管疾病、阿尔兹海默症、抑郁症等多个疾病领域的诊断研究进展,列举核酸适配体新兴技术的创新应用,以期为生物标志物的检测提供新思路,也有望为相关疾病的早期诊断和治疗提供参考。     

Functionalized carbon nanotubes and nanofibers for biosensing applications

This review summarizes recent advances in electrochemical biosensors based on carbon nanotubes (CNTs) and carbon nanofibers (CNFs) with an emphasis on applications of CNTs. CNTs and CNFs have unique electric, electrocatalytic and mechanical properties, which make them efficient materials for developing electrochemical biosensors.We discuss functionalizing CNTs for biosensors. We review electrochemical biosensors based on CNTs and their various applications (e.g., measurement of small biological molecules and environmental pollutants, detection of DNA, and immunosensing of disease biomarkers). Moreover, we outline the development of electrochemical biosensors based on CNFs and their applications. Finally, we discuss some future applications of CNTs.     

A laser fluorimeter for direct cardiac metabolism investigation

We have developed a device which includes two laser sources (nitrogen and dye lasers), an optical system, an optical fibre able to transmit both ultra-violet and infra-red light, photoreceivers, and an analogue circuit feeding a microcomputer in order to perform an in situ and on line study of NADH/NAD ratios by fluorimetry.The paper includes the scientific basis of the method, the characteristics of each part of the apparatus and possible applications to the study of cardiac metabolism or any organ that can be reached through catheterism, fibrescopy or simple transcutaneous puncture. Examples of experiments carried out to appreciate the effects of anoxia or ischemia on the tissular NADH level are presented.     

黑龙骨中两个新强心苷的结构鉴定

系统研究黑龙骨Periploca forrestii Schltr.中的化学成分, 利用各种色谱技术进行分离, 得到2个新类型的强心苷,黑龙骨苷甲和乙. 并通过化学和光谱方法(MS, ¹H, ¹³C NMR和2D NMR)鉴定其结构为: 5β-羟基-8,14β-环氧-强心 甾- 20(22)-烯-3-O-β-D-磁麻吡喃糖苷(1)和5β-羟基-8,14β-环氧-强心甾-20(22)-烯-3-O-β-D-葡萄吡喃糖基-(1→4)-β-D-磁麻吡喃糖苷(2).