石墨烯制成柔性糖尿病管理贴片

正韩国科学家日前开发出一种可穿戴式糖尿病管理贴片。这种仅有一张扑克牌大小的透明塑料薄片,在被贴在皮肤上后,不仅能监测血糖水平,还能在必要时通过皮肤释放药物降低血糖水平。传统的手指穿刺测量血糖的方法较为麻烦、患者依从性差,不少科学家希望开发出通过微创或非侵入性方法检测糖尿病患者血糖水平的方法。新研究中所采用的汗水检测法便是其中的一种。此外,     

无创血糖检测技术研究进展

糖尿病是继肿瘤和心脑血管疾病之后世界第3大威胁人类健康的重大非传染性疾病.血糖检测是医生诊断糖尿病、制定和调整治疗方案的科学依据.无创血糖检测技术取代传统的有创、微创血糖检测技术是未来发展的必然趋势,具有重要的应用价值和广阔的市场前景.近二十年来,研究人员依据不同的物理原理提出了多种无创血糖检测方法,该文按光学类和非光...     

固相萃取/液相色谱-串联质谱法测定水果蔬菜中双胍辛胺的残留量

糖尿病是继肿瘤和心脑血管疾病之后世界第3大威胁人类健康的重大非传染性疾病。血糖检测是医生诊断糖尿病、制定和调整治疗方案的科学依据。无创血糖检测技术取代传统的有创、微创血糖检测技术是未来发展的必然趋势,具有重要的应用价值和广阔的市场前景。近二十年来,研究人员依据不同的物理原理提出了多种无创血糖检测方法,该文按光学类和非光学类两大类别分别阐述各种无创血糖检测方法的基本原理及其优缺点,并探讨了无创血糖检测技术未来的发展趋势。     

钒化合物可能用于治疗糖尿病

英国哥伦比亚大学的John H.McNeiu等人发现了一种在糖尿病治疗上有广泛前景的钒化合物。糖尿病是一种体内血糖浓度高出正常范围的威胁生命的一种疾病。人们通常用胰岛素来治疗这种疾病。然而,由于胰岛素易被消化系统破坏,所以不适宜口服,而只能靠注射进入人体内。由于在注射上存在的一些困难,研究人员一直在寻找一种与胰岛素同效的适于口服的药品。     

美研究人员发明微型血糖监视仪

不久前，美国研究人员在糖尿病患者身上试验一种连续监视病人血糖浓度的微型装置，如果试验顺利，这种血糖连续监视仪将在今年夏季晚些时候正式大量推广使用，为众多的糖尿病患者提供方便。     

空腹血糖以及糖化血红蛋白对糖尿病前期患者的诊断效果评价

目的探讨空腹血糖(FPG)与糖化血红蛋白(Hb A1c)对临床中糖尿病前期的诊断价值。方法将黑龙江省佳木斯大学第一附属医院接收治疗的120例疑似糖尿病患者作为研究分析对象,将所选患者按诊断方式分为对照组和研究组(n=60),对照组采用糖化血红蛋白(Hb A1c)进行诊断,研究组采用空腹血糖(FPG)进行诊断,比较两组诊断正确率及两年内发展为糖尿病的发病率。结果研究组42例(70.0%)被确诊为糖尿病前期患者,18例(42.86%)患者发展为糖尿病;对照组中28例确诊为糖尿病前期患者,5例(17.85%)患者发展为糖尿病,确诊后转变率观察组高于对照组,差异有统计学意义(P0.05)。结论诊断糖尿病前期采用空腹血糖(FPG)与糖化血红蛋白(Hb A1c),前者临床价值更显著,建议将两种诊断方式联用,临床价值更大。     

胰岛素化学及生物化学的研究概况

胰岛素是动物胰岛β细胞分泌的一种蛋白质激素。目前医药临床上主要用来治疗糖尿病。人们对胰岛素的研究已将近有二百年的历史。早期的研究工作主要是由临床医生进行的,如1788年,医生 Cowley 就观察到胰脏功能的破坏与糖尿病的产生有密切的关系。后来又有人用外科手术方法将动物胰脏切除,从而引起人为的糖尿病。1900年,Schulze 和 Seobolew 证实胰脏兰氏(Langerhans)小岛细胞能产生一种可以降低血糖的物质。1909年,de.Meyer 将这种未知物质命名为胰岛素。但直到1922年加拿大科学家 Banting 和 Best 才真正从胰脏中抽提出胰岛素。此后,人们便开始进行胰岛素化学、生物     

胰岛封装技术及其在胰岛移植中的应用

随着全球糖尿病患者人数逐年增长,临床上亟需一种行之有效的糖尿病治疗方案。胰岛移植可通过植入具有正常功能的胰岛以替代患者体内功能受损的胰岛,从而维持正常血糖水平,有望发展为理想的糖尿病治疗方法。然而,胰岛供体资源短缺,且移植后长期服用免疫抑制剂不仅产生诸多不良反应甚至会有致癌风险。以上瓶颈极大限制了胰岛移植的临床应用。采用天然高分子、合成高分子、无机化合物等生物材料对胰岛进行封装,营造免疫隔离微环境,避免宿主免疫细胞与植入胰岛直接接触,可有效抑制免疫排斥反应。免疫隔离的同时,胰岛的封装不影响胰岛素、葡萄糖、氧气等胰岛必需或输出关键分子的交换,同时确保移植胰岛的正常生理活性及精准控制血糖水平的能力。本文综述了胰岛封装的研究现状,常用材料及设计策略,并初步展望其应用前景。     

葡萄糖敏感型水凝胶最新研究进展

糖尿病是由于胰岛素分泌不足引起的一种新陈代谢疾病,对糖尿病的有效控制在于不间断的测定血糖浓度并适时的释放胰岛素.因此,能够对环境葡萄糖浓度变化做出应答的功能型高分子材料葡萄糖敏感水凝胶,在生物化学和生物医学领域引起了极大的关注.本文综述了近几年国内外葡萄糖敏感型水凝胶的研究现状,重点介绍了应用于胰岛素释放体系和生物传感器领域的载有葡萄糖氧化酶、伴刀豆球蛋白和苯硼酸基团等葡萄糖敏感型水凝胶的作用机理和最新研究进展,展望了今后的研究方向.     

水合氧化钛的热中子非弹性散射谱

广阔的海洋中含有大量的低浓皮铀,其总量约为45亿吨。要在海水中提取铀,关键是寻找一种较好的吸附剂。经多种手段测量和筛选表明,水合氧化钛是一种较好的吸附剂,但是它的结构形式和吸铀机理至今还不很清楚。我们试图借助于中子散射的方法来探索这个问题。我们曾首次用中子非弹性散射技术,测量了不同原料制得的不同含水量的水合氧化钛的低频段振动     

Improvement of the partial least squares model performance for oral glucose intake experiments by inside mean centering and inside multiplicative signal correction.

Near infrared (NIR) spectroscopy has become a promising technique for the in vivo monitoring of glucose. Several capillary-rich locations in the body, such as the tongue, forearm, and finger, have been used to collect the in vivo spectra of blood glucose. For such an in vivo determination of blood glucose, collected NIR spectra often show some dependence on the measurement conditions and human body features at the location on which a probe touches. If NIR spectra collected for different oral glucose intake experiments, in which the skin of different patients and the measurement conditions may be quite different, are directly used, partial least squares (PLS) models built by using them would often show a large prediction error because of the differences in the skin of patients and the measurement conditions. In the present study, the NIR spectra in the range of 1300-1900 nm were measured by conveniently touching an optical fiber probe on the forearm skin with a system that was developed for in vivo measurements in our previous work. The spectra were calibrated to resolve the problem derived from the difference of patient skin and the measurement conditions by two proposed methods, inside mean centering and inside multiplicative signal correction (MSC). These two methods are different from the normal mean centering and normal multiplicative signal correction (MSC) that are usually performed to spectra in the calibration set, while inside mean centering and inside MSC are performed to the spectra in every oral glucose intake experiment. With this procedure, spectral variations resulted from the measurement conditions, and human body features will be reduced significantly. More than 3000 NIR spectra were collected during 68 oral glucose intake experiments, and calibrated. The development of PLS calibration models using the spectra show that the prediction errors can be greatly reduced. This is a potential chemometric technique with simplicity, rapidity and efficiency in the pretreatment of NIR spectra collected during oral glucose intake experiments.     

Zinc, copper and aluminium in the corpuscular components of peripheral blood in patients with pre-terminal and terminal renal failure

Summary Trace elements play an essential role in the activation and regulation of metabolic processes. By using the flameless graphite furnace-AAS, accurate results can be obtained. In order to verify blood cells as more representative than plasma to reflect the whole body content of trace elements at uremic state, two patient groups, one with preterminal renal failure (n=40) and the second with chronic renal failure undergoing hemodialysis (n=20) were examined. The concentration levels of zinc, copper and aluminium were measured in different matrices, i.e. whole blood, plasma and corpuscular blood components. The analytical technique is eligible to isolate mono- and polymorphnuclear leucocytes for the determination of intracellular contents. In agreement with other reports, zinc and copper were decreased and aluminium was increased in the plasma of both patient groups. Different results could be found for intracellular contents with mean zinc concentration of erythrocytes, thrombocytes and leucocytes between mean and higher levels, though staying within normal values. Copper was decreased in erythrocytes and increased in thrombocytes, but not detectable in leucocytes. The results of this study point out the differences between the plasmatic and intracellular alteration of trace element contents in uremic patients. However, the concentration levels of all cellular compartments show high standard deviation, which shows the necessity of measuring additional matrices, e.g. plasma. Uremic symptoms relate to the disorders of the trace element homeostasis. Regarding the increased fragility of erythrocytes with shortened life duration, decreased copper contents could play an essential role. Increased aluminium concentration levels might also be one of the interfering factors in the uremic thrombocytopathy. Yet the measurement of the plasma content is inevitable to diagnose and reflect the whole body content of trace elements at uremic state. By keeping analysis control, important information about progression and influence of therapy can be obtained.Dedicated to Professor Dr. Wilhelm Fresenius on the occasion of his 80th birthday     

Ex-vivo determination of blood glucose by microdialysis in combination with infrared attenuated total reflection spectroscopy

Several biosensors have been developed for continuous monitoring of human blood glucose, which is desirable for insulin-dependent diabetic patients. Developments in the field of quantitative assays using infrared attenuated total reflection spectroscopy allow the determination of metabolites at low concentrations. The microdialysis technique can provide a continuous sampling of extracellular body fluids. As only compounds of low molecular weight are passed on, infrared spectrometric quantitation is eased considerably. Samples were obtained by microdialysis of human blood plasma and aqueous glucose solutions. Multivariate calibration by partial least-squares was evaluated for its analytical performance in ex-vivo blood glucose monitoring. Mean squared prediction errors obtained by cross validation were 5.4 mg/dL for dialysate samples from different patients and 1.3 mg/ dL for dialysates from glucose solutions. Further investigations were carried out to achieve miniaturization of the measuring and detection device. Received: 5 December 1996 / Revised: 20 March 1997 / Accepted: 29 March 1997     

Ex-vivo determination of blood glucose by microdialysis in combination with infrared attenuated total reflection spectroscopy

Several biosensors have been developed for continuous monitoring of human blood glucose, which is desirable for insulin-dependent diabetic patients. Developments in the field of quantitative assays using infrared attenuated total reflection spectroscopy allow the determination of metabolites at low concentrations. The microdialysis technique can provide a continuous sampling of extracellular body fluids. As only compounds of low molecular weight are passed on, infrared spectrometric quantitation is eased considerably. Samples were obtained by microdialysis of human blood plasma and aqueous glucose solutions. Multivariate calibration by partial least-squares was evaluated for its analytical performance in ex-vivo blood glucose monitoring. Mean squared prediction errors obtained by cross validation were 5.4 mg/dL for dialysate samples from different patients and 1.3 mg/ dL for dialysates from glucose solutions. Further investigations were carried out to achieve miniaturization of the measuring and detection device.     

Infrared spectroscopic analysis of human interstitial fluid in vitro and in vivo using FT-IR spectroscopy and pulsed quantum cascade lasers (QCL): Establishing a new approach to non invasive glucose measurement

Interstitial fluid, i.e. the liquid present in the outermost layer of living cells of the skin between the Stratum corneum and the Stratum spinosum, was analyzed by Fourier transform infrared spectroscopy and by infrared spectroscopy using pulsed quantum cascade infrared lasers with photoacoustic detection. IR spectra of simulated interstitial fluid samples and of real samples from volunteers in the 850-1800cm(-1) range revealed that the major components of interstitial fluid are albumin and glucose within the physiological range, with only traces of sodium lactate if at all. The IR absorbance of glucose in interstitial fluid in vivo was probed in healthy volunteers using a setup with quantum cascade lasers and photoacoustic detection previously described. A variation of blood glucose between approx. 80mg/dl and 250mg/dl in the volunteers was obtained using the standard oral glucose tolerance test (OGT). At two IR wavelengths, 1054cm(-1) and 1084cm(-1), a reasonable correlation between the photoacoustic signal from the skin and the blood glucose value as determined by conventional glucose test sticks using blood from the finger tip was obtained. The infrared photoacoustic glucose signal (PAGS) may serve as the key for a non-invasive glucose measurement, since the glucose content in interstitial fluid closely follows blood glucose in the time course and in the level (a delay of some minutes and a level of approx. 80-90% of the glucose level in blood). Interstitial fluid is present in skin layers at a depth of only 15-50μm and is thus within the reach of mid-IR energy in an absorbance measurement. A non-invasive glucose measurement for diabetes patients based on mid-infrared quantum cascade lasers and photoacoustic detection could replace the conventional measurement using enzymatic test stripes and a drop of blood from the finger tip, thus reducing pain and being a cost-efficient alternative for millions of diabetes patients.     

Highly sensitive glucose sensor based on work function changes measured by an EMOSFET

In this paper, glucose is potentiometrically measured by using a specific field effect transistor, the EMOSFET. In this device, glucose oxidase is immobilized within a bovine serum albumin matrix, using glutaraldehyde. This layer is deposited on the top of an electroactive Os-polyvinylpyridine layer containing horseradish peroxidase, which is used as the gate material of the FET. The basic principle of the sensor is to measure the glucose concentration by means of measuring the change in the work function of the electroactive gate due to its redox reaction with the H2O2, generated by the reaction between glucose and glucose oxidase. The change in the work function can be detected as a change in the threshold voltage of the FET. Moreover, a measuring mode called "constant current potentiometry" has been applied to improve the sensitivity of the sensor. The sensitivity of the sensor working in this mode is found to be much higher than the Nernstian value. The experimental results show that the detection limit of the sensor can be tuned depending on the value of the applied current and the glucose oxidase concentration in the gate.     

Determination of Glucose in Diluted Blood with a Thermal Flow Injection Analysis Biosensor

Abstract

The glucose concentration in diluted whole blood has been measured, using a miniaturized thermal biosensor based on the enzyme thermistor principle. The biosensor is a small flow injection system. A sample volume of 20μl is injected into a flow of 50μl/min. The heat produced when the sample passes the enzyme column is measured with a thermistor connected to a Wheatstone bridge. The enzyme column contains glucose oxidase and catalase co-immobilized on a solid support material. Samples of whole blood usually cause problems in flow-systems. The blood cells tend to block the enzyme column and the back pressure increases. We have tested a superporous agarose material as enzyme support material using tenfold diluted samples of whole human blood. The blood was collected from the finger-tip and diluted with buffer containing an anticoagulant and sodium fluoride. The number of samples possible to inject and the accuracy compared to the Boehringer Mannheim Reflolux have been determined. At least 100 ten-fold diluted blood samples could be injected on a micro-column of superporous agarose. The obtained glucose concentration correlated well with the one obtained with the reference instrument.     

Association between angiotensin-1 converting enzyme gene polymorphism and the metabolic syndrome in a Mexican population

Metabolic Syndrome (MS) is recognized as a cluster of cardiovascular risk factors. All components of MS have a genetic base. Genes of the renin angiotensin system are potential candidate genes for MS. We investigated whether angiotensin converting enzyme (ACE) gene polymorphism increases susceptibility to MS as an entity in a Mexican population. In a cross-sectional study, 514 individuals were studied including 245 patients with MS and 269 subjects without MS criteria. ACE gene polymorphism was detected using PCR. MS was defined according to The National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III) criteria, except that the raised fasting plasma glucose 相似文献   

Measurement of Glucose Concentration in Blood Plasma Based on a Wireless Magnetoelastic Biosensor

Abstract

A wireless magnetoelastic glucose biosensor in blood plasma is described, based on using a mass sensitive magnetoelastic sensor as transducer. The glucose biosensor was fabricated by coating the ribbon‐like, magnetoelastic sensor with a pH sensitive polymer and a biolayer of glucose oxidase (GOx) and catalase. The pH response polymer swells or shrinks, thereby changing sensor mass loading, respectively, in response to increase or decrease of pH values. The GOx–catalyzed oxidation of the glucose in blood plasma produces gluconic acid, resulting in the pH sensitive polymer shrinking, which in turn decreases the sensor mass loading. The results show that the proposed magnetoelastic glucose biosensor can be successfully applied to determine the concentration of glucose in blood plasma. At glucose concentration range of 2.5–20.0 mmol/l, the biosensor responses are reversible and linear, with a detection limit of 1.2 mmol/l. Since no physical connections between the sensor and the monitoring instruments are required, this proposed biosensor can potentially be applied to in vivo and in situ measurement of glucose concentration in physiological fluids.     

The determination of selenium concentration in blood and tumour tissues of breast cancer patients in Syria using instrumental neutron activation analysis

The aim of this study was to investigate the relationship of selenium concentration in blood components and tumour tissues of breast cancer patients and healthy volunteers (control), in Syria, using instrumental neutron activation analysis (INAA). Red blood cells and serum selenium concentrations were determined in 50 healthy volunteers aged 25-70 years and 70 breast cancer patients aged 25-84 years. Selenium levels were also measured in malignant and adjacent normal tissues from breast cancer patients. The accuracy of the analysis was evaluated by co-analyses of international reference materials. The results showed that selenium concentration in serum and RBC was significantly lower among breast cancer patients compared to healthy volunteers (P<0.001). The results also showed that the selenium concentration was significantly higher in the cancer tissues compared to adjacent normal tissues (P<0.001). We conclude that there is a good indication for selenium deviation in blood and malignant tissue of breast cancer patients compared to that of healthy volunteers. This revised version was published online in July 2006 with corrections to the Cover Date.