共查询到20条相似文献，搜索用时 31 毫秒
2.
Effect of magnesium ions on the binding of bilirubin to erythrocytes of different mammalian species, namely, human, buffalo,
goat and sheep was studied. Increase in the concentration of magnesium ions led to a gradual increase in the erythrocyte-bound
bilirubin in both human and buffalo erythrocytes whereas in sheep and goat erythrocytes, the pronounced increase was found
beyond 2.0 and 2.7 mM MgCl2 concentrations respectively. Percentage increase in erythrocyte-bound bilirubin was found highest in human erythrocytes followed
by buffalo and sheep erythrocytes and minimum in goat erythrocytes. These differences in the binding of bilirubin to different
mammalian erythrocytes can be attributed to the differential shielding effect of metal ions which involves the masking of
negatively charged phosphate of phospholipids found on the erythrocyte surface. 相似文献
3.
Massimo Muratore Vlastimil Srsen Martin Waterfall Andrew Downes Ronald Pethig 《Biomicrofluidics》2012,6(3)
Myoblasts are muscle derived mesenchymal stem cell progenitors that have great potential for use in regenerative medicine, especially for cardiomyogenesis grafts and intracardiac cell transplantation. To utilise such cells for pre-clinical and clinical applications, and especially for personalized medicine, it is essential to generate a synchronised, homogenous, population of cells that display phenotypic and genotypic homogeneity within a population of cells. We demonstrate that the biomarker-free technique of dielectrophoresis (DEP) can be used to discriminate cells between stages of differentiation in the C2C12 myoblast multipotent mouse model. Terminally differentiated myotubes were separated from C2C12 myoblasts to better than 96% purity, a result validated by flow cytometry and Western blotting. To determine the extent to which cell membrane capacitance, rather than cell size, determined the DEP response of a cell, C2C12 myoblasts were co-cultured with GFP-expressing MRC-5 fibroblasts of comparable size distributions (mean diameter ∼10 μm). A DEP sorting efficiency greater than 98% was achieved for these two cell types, a result concluded to arise from the fibroblasts possessing a larger membrane capacitance than the myoblasts. It is currently assumed that differences in membrane capacitance primarily reflect differences in the extent of folding or surface features of the membrane. However, our finding by Raman spectroscopy that the fibroblast membranes contained a smaller proportion of saturated lipids than those of the myoblasts suggests that the membrane chemistry should also be taken into account. 相似文献
4.
Pradeep Naik S. Indira R. M. Pitchappan T. Malati 《Indian journal of clinical biochemistry : IJCB》1991,6(2):119-123
Antibodies against human leucocyte antigens (HLA) in sera from uni and multiparous women are the potential source of HLA reagent.
The present study was undertaken to screen 169 sera from pregnant women for the presence of HLA antibodies employing 26 panel
cells (Peripheral blood lymphocytes) having known HLA phenotypes. 20.7% (35/169) sera were found to be positive for HLA class-1
antibodies. Present study generated one monospecific, (r=0.6 for A32) the duospecific sera (r=0.5 for A2 B35, r=0.47 A1 DR6
and r=0.7 A28 B51), and rest multispecific sera (r=below 0.4). These positive sera will be utilized as HLA reagents in future
studies for tissue typing. 相似文献
5.
Mariangela Mortato Laura Blasi Giovanna Barbarella Simona Argentiere Giuseppe Gigli 《Biomicrofluidics》2012,6(4)
Herein proposed is a simple system to realize hands-free labeling and simultaneous detection of two human cell lines within a microfluidic device. This system was realized by novel covalent immobilization of pH-responsive poly(methacrylic acid) microgels onto the inner glass surface of an assembled polydimethylsiloxane/glass microfluidic channel. Afterwards, selected thiophene labeled monoclonal antibodies, specific for recognition of CD4 antigens on T helper/inducer cells and CD19 antigens on B lymphocytes cell lines, were encapsulated in their active state by the immobilized microgels. When the lymphocytes suspension, containing the two target subpopulations, was flowed through the microchannel, the physiological pH of the cellular suspension induced the release of the labeled antibodies from the microgels and thus the selective cellular staining. The selective pH-triggered staining of the CD4- and CD19-positive cells was investigated in this preliminary experimental study by laser scanning confocal microscopy. This approach represents an interesting and versatile tool to realize cellular staining in a defined module of lab-on-a-chip devices for subsequent detection and counting. 相似文献
6.
为了研究4条人工合成抗菌肽的抑菌和溶血作用。在大肠杆菌悬浮液和绵羊血红细胞悬浮液中,分别加入不同溶度的人工合成抗菌肽,观察其抑菌效果和溶血作用。同时,用圆二色谱仪测定抗菌肽的二级结构。在4条人工合成抗菌肽中,抗菌肽CM-S的抑菌效果为最佳,最小抑菌溶度为25μg/mL,而LB平板菌落的杀菌溶度为50μg/mL;在对绵羊血红细胞的溶血试验中,CM-S在50μg/mL时无溶血作用,100μg/mL时只表现出轻微溶血特性;用圆二色谱仪测定CM-S的二级结构,在2.5%SDS溶液中,208 nm和222 nm出现典型α-螺旋特征峰。人工合成抗菌肽CM-S,含有17个氨基酸,呈典型α-螺旋结构,对大肠杆菌的抑杀效果显著,且溶血性很低,有良好的临床药物开发前景。 相似文献
7.
8.
In this paper, a detailed numerical and experimental investigation into the optimisation of hydrodynamic micro-trapping arrays for high-throughput capture of single polystyrene (PS) microparticles and three different types of live cells at trapping times of 30 min or less is described. Four different trap geometries (triangular, square, conical, and elliptical) were investigated within three different device generations, in which device architecture, channel geometry, inter-trap spacing, trap size, and trap density were varied. Numerical simulation confirmed that (1) the calculated device dimensions permitted partitioned flow between the main channel and the trap channel, and further, preferential flow through the trap channel in the absence of any obstruction; (2) different trap shapes, all having the same dimensional parameters in terms of depth, trapping channel lengths and widths, main channel lengths and widths, produce contrasting streamline plots and that the interaction of the fluid with the different geometries can produce areas of stagnated flow or distorted field lines; and (3) that once trapped, any motion of the trapped particle or cell or a shift in its configuration within the trap can result in significant increases in pressures on the cell surface and variations in the shear stress distribution across the cell’s surface. Numerical outcomes were then validated experimentally in terms of the impact of these variations in device design elements on the percent occupancy of the trapping array (with one or more particles or cells) within these targeted short timeframes. Limitations on obtaining high trap occupancies in the devices were shown to be primarily a result of particle aggregation, channel clogging and the trap aperture size. These limitations could be overcome somewhat by optimisation of these device design elements and other operational variables, such as the average carrier fluid velocity. For example, for the 20 μm polystyrene microparticles, the number of filled traps increased from 32% to 42% during 5–10 min experiments in devices with smaller apertures. Similarly, a 40%–60% reduction in trapping channel size resulted in an increase in the amount of filled traps, from 0% to almost 90% in 10 min, for the human bone marrow derived mesenchymal stem cells, and 15%–85% in 15 min for the human embryonic stem cells. Last, a reduction of the average carrier fluid velocity by 50% resulted in an increase from 80% to 92% occupancy of single algae cells in traps. Interestingly, changes in the physical properties of the species being trapped also had a substantial impact, as regardless of the trap shape, higher percent occupancies were observed with cells compared to single PS microparticles in the same device, even though they are of approximately the same size. This investigation showed that in microfluidic single cell capture arrays, the trap shape that maximizes cell viability is not necessarily the most efficient for high-speed single cell capture. However, high-speed trapping configurations for delicate mammalian cells are possible but must be optimised for each cell type and designed principally in accordance with the trap size to cell size ratio. 相似文献
9.
Andrea Te?ija Kuna 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2013,23(1):28-42
Inflammatory bowel disease (IBD) is a heterogeneous group of chronic inflammatory disorders of the gastrointestinal tract with two main distinguishable entities, Crohn’s disease (CD) and ulcerative colitis (UC). IBD-unclassified (IBD-U) is a diagnosis that covers the “grey” zone of diagnostic uncertainty between UC and CD. Current diagnosis of IBD relies on the clinical, endoscopic, radiological, histological and biochemical features, but this approach has shortcomings especially in cases of overlapping symptoms of CD and UC. The need for a diagnostic tool that would improve the conventional methods in IBD diagnosis directed the search towards potential immunological markers, since an aberrant immune response against microbial or endogenous antigens in a genetically susceptible host seems to be implicated in IBD pathogenesis. The spectrum of antibodies to different microbial antigens and autoantibodies associated with IBD is rapidly expanding. Most of these antibodies are associated with CD like anti-glycan antibodies: anti-Saccharomices cerevisiae (ASCA) and the recently described anti-laminaribioside (ALCA), anti-chitobioside (ACCA), anti-mannobioside (AMCA), anti-laminarin (anti-L) and anti-chitin (anti-C) antibodies; in addition to other antibodies that target microbial antigens: anti-outer membrane porin C (anti-OmpC), anti-Cbir1 flagellin and anti-I2 antibody. Also, autoantibodies targeting the exocrine pancreas (PAB) were shown to be highly specific for CD. In contrast, UC has been associated with anti-neutrophil cytoplasmic autoantibodies (pANCA) and antibodies against goblet cells (GAB). Current evidence suggests that serologic panels of multiple antibodies are useful in differential diagnosis of CD versus UC and can be a valuable aid in stratifying patients according to disease phenotype and risk of complications. 相似文献
10.
Vickers DA Kulik M Hincapie M Hancock WS Dalton S Murthy SK 《Biomicrofluidics》2012,6(2):24122-2412210
Embryonic stem (ES) cells are capable of proliferating and differentiating to form cells of the three embryonic germ layers, namely, endoderm, mesoderm, and ectoderm. The utilization of human ES cell derivatives requires the ability to direct differentiation to specific lineages in defined, efficient, and scalable systems. Better markers are needed to identify early differentiation. Lectins have been reported as an attractive alternative to the common stem cell markers. They have been used to identify, characterize, and isolate various cell subpopulations on the basis of the presentation of specific carbohydrate groups on the cell surface. This article demonstrates how simple adhesion assays in lectin-coated microfluidic channels can provide key information on the interaction of lectins with ES and definitive endoderm cells and thereby track early differentiation. The microfluidic approach incorporates both binding strength and cell surface receptor density, whereas traditional flow cytometry only incorporates the latter. Both approaches are examined and shown to be complementary with the microfluidic approach providing more biologically relevant information. 相似文献
11.
干细胞具有自我更新和多分化潜能。随着研究的不断深入,干细胞已成为生命科学领域最令人瞩目的研究项目之一,在为基础研究做出巨大贡献的同时也为再生医学展现了美好的应用前景。然而由于国家、民族、宗教信仰及政党等不同,干细胞在各地区发展程度并不一致。最近美国总统奥巴马宣布联邦政府将支持干细胞的研究,这势必会对目前干细胞研究领域的发展格局产生深远的影响。而我国对干细胞及治疗性克隆的研究一直持支持态度,并且在该领域取得了一定的原创性成果。因此面对新的研究格局,我国应继续积极制定相应对策,不断推动干细胞的研究,并且加速干细胞在产业化领域中的应用。 相似文献
12.
Precisely controlling the spatial distribution of biomolecules on biomaterial surface is important for directing cellular activities in the controlled cell microenvironment. This paper describes a polydimethylsiloxane (PDMS) gradient-generating microfluidic device to immobilize the gradient of cellular adhesive Arg-Gly-Asp (RGD) peptide on poly (ethylene glycol) (PEG) hydrogel. Hydrogels are formed by exposing the mixture of PEG diacrylate (PEGDA), acryloyl-PEG-RGD, and photo-initiator with ultraviolet light. The microfluidic chip was simulated by a fluid dynamic model for the biomolecule diffusion process and gradient generation. PEG hydrogel covalently immobilized with RGD peptide gradient was fabricated in this microfluidic device by photo-polymerization. Bone marrow derived rat mesenchymal stem cells (MSCs) were then cultured on the surface of RGD gradient PEG hydrogel. Cell adhesion of rat MSCs on PEG hydrogel with various RGD gradients were then qualitatively and quantitatively analyzed by immunostaining method. MSCs cultured on PEG hydrogel surface with RGD gradient showed a grated fashion for cell adhesion and spreading that was proportional to RGD concentration. It was also found that 0.107–0.143 mM was the critical RGD concentration range for MSCs maximum adhesion on PEG hydrogel. 相似文献
13.
D. I. Braghirolli F. Zamboni P. C. Chagastelles D. J. Moura J. Saffi J. A. P. Henriques D. A. Pilger P. Pranke 《Biomicrofluidics》2013,7(4)
Bio-electrospraying (BES) is a technique used for the processing of cells and can be applied to tissue engineering. The association of BES with scaffold production techniques has been shown to be an interesting strategy for the production of biomaterials with cells homogeneously distributed in the entire structure. Various studies have evaluated the effects of BES on different cell types. However, until the present moment, no studies have evaluated the impact of BES time on mesenchymal stem cells (MSC). Therefore, the aim of this work was to standardise the different parameters of BES (voltage, flow rate, and distance of the needle from the collecting plate) in relation to cell viability and then to evaluate the impact of BES time in relation to viability, proliferation, DNA damage, maintenance of plasticity and the immunophenotypic profile of MSC. Using 15 kV voltage, 0.46 ml/h flow rate and 4 cm distance, it was possible to form a stable and continuous jet of BES without causing a significant reduction in cell viability. Time periods between 15 and 60 min of BES did not cause alterations of viability, proliferation, plasticity, and immunophenotypic profile of the MSC. Time periods above 30 min of BES resulted in DNA damage; however, the DNA was able to repair itself within five hours. These results indicate that bio-electrospraying is an adequate technique for processing MSC which can be safely applied to tissue engineering and regenerative medicine. 相似文献
14.
赣中红壤丘陵区草食畜牧业发展潜力及其经济效益评价 总被引：1，自引：0，他引：1
近年来赣中红壤丘陵区的畜牧业虽有一定发展 ,但在畜禽资源配置与利用方面存在的种种问题 ,使得区内畜牧业 ,尤其是草食畜牧业处于缓慢发展甚至停滞不前的状态。该文在分析千烟洲试区的试验数据与农户调查资料的基础上 ,指出以猪为主的单一产业结构 ,肉牛、山羊、鹅等草食畜产品比重低及饲养管理粗放是制约该区畜牧业发展的主要问题。同时从土地生产率、市场与政策限制以及启动资金等方面探讨了传统草食畜牧业发展缓慢的原因。分析和评价表明 ,南方草食畜牧业的市场潜力巨大 ,且种草养畜的经济效益明显高出传统畜牧业。因此 ,该区今后畜牧业发展方向应利用天然草地、果园空地和冬闲田建立人工草地 ,种草养畜 ,逐步形成以肉牛为主 ,山羊和鹅为辅的草食畜种占一定比例的合理畜牧业结构 相似文献
15.
诱导多能干细胞因其具有类似胚胎干细胞的自我更新和分化潜能而成为生物学和医学等领域的研究热点之一。本文针对诱导多能干细胞的国内外专利文献进行检索、收集、统计及分析,综述了诱导多能干细胞的专利申请量、申请人分布及国别分布的特点,分析了诱导多能干细胞的诱导分化心肌细胞的主要专利技术路线,及诱导多能干细胞在临床上的应用,以期为今后的诱导多能干细胞领域的研究提供参考意见。 相似文献
16.
Bio-electrospraying and aerodynamically assisted bio-jetting are two direct cell handling approaches recently pioneered, which have demonstrated significant applicability to the life sciences. These two bioprotocols have undergone scientific rigor, which have seen these techniques been explored in conjunction with a wide range of immortalized, primary and stem cells, and those whole organisms. Those studies have demonstrated a cellular population of >70% viable post-treatment in comparison with controls. Although, these studies assessed cellular viability, cell surface molecules play a critical role in several cellular functions, in particular, have importance to tissue engineering and regenerative medicine. Thus, in the studies reported herein, we demonstrate post-treated viable cells retain their cell surface marker expression levels in comparison to controls, over both short and long time points. Therefore, these studies further push back the frontiers of both bio-electrosprays and aerodynamically assisted bio-jetting in their endeavor as novel strategies for tissue engineering and regenerative biology∕medicine with possible targeted clinical utility. 相似文献
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18.
Embryonic stem cells (ESCs) are pluripotent with multilineage potential to differentiate into virtually all cell types in the organism and thus hold a great promise for cell therapy and regenerative medicine. In vitro differentiation of ESCs starts with a phase known as embryoid body (EB) formation. EB mimics the early stages of embryogenesis and plays an essential role in ESC differentiation in vitro. EB uniformity and size are critical parameters that directly influence the phenotype expression of ESCs. Various methods have been developed to form EBs, which involve natural aggregation of cells. However, challenges persist to form EBs with controlled size, shape, and uniformity in a reproducible manner. The current hanging-drop methods are labor intensive and time consuming. In this study, we report an approach to form controllable, uniform-sized EBs by integrating bioprinting technologies with the existing hanging-drop method. The approach presented here is simple, robust, and rapid. We present significantly enhanced EB size uniformity compared to the conventional manual hanging-drop method. 相似文献
19.
Cellular transplantation is a promising technology with great clinical potential in regenerative medicine and disease management. However, effective control over patient immunological response is essential. The encapsulation of cells within hydrogel microspheres is an increasingly prevalent method for the protection of cellular grafts from immune rejection. Microfluidic “chip” reactors present elegant solutions to several capsule generation issues, including the requirement for intercapsule uniformity, high reproducibility, and sterile, good manufacturing practice compliance. This study presents a novel method for the on-chip production of stable, highly monodisperse alginate microspheres and demonstrates its utility in the encapsulation of an immortalized human-derived cell line. Four populations of immortalized human embryonic kidney cells (HEK293) were encapsulated on chip within monodisperse alginate capsules. Cell viability measurements were recorded for each of the four encapsulated populations for 90 days. 相似文献
20.
《Electronic Journal of Biotechnology》2014,17(5):211-216
BackgroundSpermatogonial stem cells (SSCs) are important for the production of interspecies germ line chimeras. The interspecies germ cell transfer technique has been suggested as a way to conserve endangered birds. Our objective was to develop a technique for restoring endangered birds by developing interspecies germ line chimeras between pheasant (Phasianus colchicus) and chicken (Gallus gallus) with SSCs.ResultsSSCs were isolated from the surgically removed testis of a pheasant. Growth conditions for pheasant SSCs were established by co-culturing STO (SIM mouse embryo-derived thioguanine and ouabain resistant) cells and pheasant SSCs. The colony-forming cells divided and proliferated stably to yield an established SSC line. Pheasant SSCs showed strong reactivity for GDNF family receptor alpha1 (GFRα1) marker. Finally, production of germ line chimeras was attempted by transferring pheasant SSCs into recipient embryos. Although final embryo survival was 5.6% (20/354), the initial survival rate was 88% (312/354). To measure the percent transfer of donor SSC to gonads, the pheasant SSCs were labeled with PKH 26 fluorescent dye. We observed 30% donor cells and 9.48% c-kit/CD117-positive cells in the gonads of recipient chickens. Donor SSCs were thus stably engrafted in the recipient gonads.ConclusionsThis study showed that SSCs can be used as a tool for the conservation of endangered birds and the production of germ line chimeras. Our findings yield insights into how we may use the pheasant spermatogonial stem cell line for efficient production of interspecies germ line chimeras and ultimately, to the restoration of endangered birds. 相似文献