排序方式: 共有187条查询结果,搜索用时 15 毫秒
71.
Zoltan Cseresnyes Laura Oehme Volker Andresen Anje Sporbert Anja E. Hauser Raluca Niesner 《Journal of visualized experiments : JoVE》2014,(86)
Monitoring cellular communication by intravital deep-tissue multi-photon microscopy is the key for understanding the fate of immune cells within thick tissue samples and organs in health and disease. By controlling the scanning pattern in multi-photon microscopy and applying appropriate numerical algorithms, we developed a striped-illumination approach, which enabled us to achieve 3-fold better axial resolution and improved signal-to-noise ratio, i.e. contrast, in more than 100 µm tissue depth within highly scattering tissue of lymphoid organs as compared to standard multi-photon microscopy. The acquisition speed as well as photobleaching and photodamage effects were similar to standard photo-multiplier-based technique, whereas the imaging depth was slightly lower due to the use of field detectors. By using the striped-illumination approach, we are able to observe the dynamics of immune complex deposits on secondary follicular dendritic cells – on the level of a few protein molecules in germinal centers. 相似文献
72.
Brian M. Wiczer Raluca MarcuBrian J. Hawkins 《Biochemical and biophysical research communications》2014
The isothiourea derivative, KB-R7943, inhibits the reverse-mode of the plasma membrane sodium/calcium exchanger and protects against ischemia/reperfusion injury. The mechanism through which KB-R7943 confers protection, however, remains controversial. Recently, KB-R7943 has been shown to inhibit mitochondrial calcium uptake and matrix overload, which may contribute to its protective effects. While using KB-R7943 for this purpose, we find here no evidence that KB-R7943 directly blocks mitochondrial calcium uptake. Rather, we find that KB-R7943 inhibits opening of the mitochondrial permeability transition pore in permeabilized cells and isolated liver mitochondria. Furthermore, we find that this observation correlates with protection against calcium ionophore-induced mitochondrial membrane potential depolarization and cell death, without detrimental effects to basal mitochondrial membrane potential or complex I-dependent mitochondrial respiration. Our data reveal another mechanism through which KB-R7943 may protect against calcium-induced injury, as well as a novel means to inhibit the mitochondrial permeability transition pore. 相似文献
73.
Iuliana Moldoveanu Camelia Stanciu Gavan Raluca‐Ioana Stefan‐van Staden 《Journal of molecular recognition : JMR》2014,27(11):653-658
Multimode sensing was proposed for molecular screening and recognition of HER‐1 in whole blood. The tools used for molecular recognition were platforms based on nanostructured materials such as the complex of Mn(III) with meso‐tetra (4‐carboxyphenyl) porphyrin, and maltodextrin (dextrose equivalence between 4 and 7), immobilized in diamond paste, graphite paste or C60 fullerene paste. The identification of HER‐1 in whole‐blood samples, at molecular level, is performed using stochastic mode and is followed by the quantification of it using stochastic and differential pulse voltammetry modes. HER‐1 can be identified in the concentration range between 280 fg/ml and 4.86 ng/ml using stochastic mode, this making possible the early detection of cancers such as gastrointestinal, pancreatic and lung cancers. The recovery tests performed using whole‐blood samples proved that the platforms can be used for identification and quantification of HER‐1 with high sensitivity and reliability in such samples, these making them good molecular screening tools. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
74.
Binding of proteins to particular DNA sites across the genome is a primary determinant of specificity in genome maintenance and gene regulation. DNA-binding specificity is encoded at multiple levels, from the detailed biophysical interactions between proteins and DNA, to the assembly of multi-protein complexes. At each level, variation in the mechanisms used to achieve specificity has led to difficulties in constructing and applying simple models of DNA binding. We review the complexities in protein–DNA binding found at multiple levels and discuss how they confound the idea of simple recognition codes. We discuss the impact of new high-throughput technologies for the characterization of protein–DNA binding, and how these technologies are uncovering new complexities in protein–DNA recognition. Finally, we review the concept of multi-protein recognition codes in which new DNA-binding specificities are achieved by the assembly of multi-protein complexes. 相似文献
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76.
Expanding Two-Photon Intravital Microscopy to the Infrared by Means of Optical Parametric Oscillator
Josephine Herz Volker Siffrin Anja E. Hauser Tina Leuenberger Helena Radbruch Frauke Zipp Raluca A. Niesner 《Biophysical journal》2010,98(4):715-723
Chronic inflammation in various organs, such as the brain, implies that different subpopulations of immune cells interact with the cells of the target organ. To monitor this cellular communication both morphologically and functionally, the ability to visualize more than two colors in deep tissue is indispensable. Here, we demonstrate the pronounced power of optical parametric oscillator (OPO)-based two-photon laser scanning microscopy for dynamic intravital imaging in hardly accessible organs of the central nervous and of the immune system, with particular relevance for long-term investigations of pathological mechanisms (e.g., chronic neuroinflammation) necessitating the use of fluorescent proteins. Expanding the wavelength excitation farther to the infrared overcomes the current limitations of standard Titanium:Sapphire laser excitation, leading to 1), simultaneous imaging of fluorophores with largely different excitation and emission spectra (e.g., GFP-derivatives and RFP-derivatives); and 2), higher penetration depths in tissue (up to 80%) at higher resolution and with reduced photobleaching and phototoxicity. This tool opens up new opportunities for deep-tissue imaging and will have a tremendous impact on the choice of protein fluorophores for intravital applications in bioscience and biomedicine, as we demonstrate in this work. 相似文献
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78.
Romulus Ion Scorei Cristina Ciofrangeanu Raluca Ion Anisoara Cimpean Bianca Galateanu Valentina Mitran Dana Iordachescu 《Biological trace element research》2010,135(1-3):334-344
The present study is supported by our previous findings suggesting that calcium fructoborate (CF) has anti-inflammatory and antioxidant properties. Thus, we investigated the effects of CF on a model for studying inflammatory disorders in vitro represented by lipopolysaccharide (LPS)-stimulated murine macrophage RAW 264.7 cells. This investigation was performed by analyzing the levels of some mediators released during the inflammatory process: cytokines such as tumor necrosis factor-α (TNF-α), interleukins IL-1β and IL-6 as well as cyclooxygenase-2 (COX-2), the main enzyme responsible for endotoxin/LPS-induced prostaglandin synthesis by macrophages. We also measured production of nitric oxide (NO) that plays an important role in the cytotoxicity activity of macrophages towards microbial pathogens. After CF treatment of LPS-stimulated macrophages we found an up-regulation of TNF-α protein level in culture medium, no significant changes in the level of COX-2 protein expression and a decrease in NO production as well as in IL-1β and IL-6 release. Collectively, this series of experiments indicate that CF affect macrophage production of inflammatory mediators. However, further research is required in order to establish whether CF treatment can be beneficial in suppression of pro-inflammatory cytokine production and against progression of endotoxin-related diseases. 相似文献
79.
Irina Baran Constanta Ganea Agata Scordino Francesco Musumeci Vincenza Barresi Salvatore Tudisco Simona Privitera Rosaria Grasso Daniele F. Condorelli Ioan Ursu Virgil Baran Eva Katona Maria-Magdalena Mocanu Marisa Gulino Raluca Ungureanu Mihaela Surcel Cornel Ursaciuc 《Cell biochemistry and biophysics》2010,58(3):169-179
Menadione (MD) is an effective cytotoxic drug able to produce intracellularly large amounts of superoxide anion. Quercetin (QC), a widely distributed bioflavonoid, can exert both antioxidant and pro-oxidant effects and is known to specifically inhibit cell proliferation and induce apoptosis in different cancer cell types. We have investigated the relation between delayed luminescence (DL) induced by UV-laser excitation and the effects of MD, hydrogen peroxide, and QC on apoptosis and cell cycle in human leukemia Jurkat T-cells. Treatments with 500 μM H2O2 and 250 μM MD for 20 min produced 66.0 ± 4.9 and 46.4 ± 8.6% apoptotic cell fractions, respectively. Long-term (24 h) pre-exposure to 5 μM, but not 0.5 μM QC enhanced apoptosis induced by MD, whereas short-term (1 h) pre-incubation with 10 μM QC offered 50% protection against H2O2-induced apoptosis, but potentiated apoptosis induced by MD. Since physiological levels of QC in the blood are normally less than 10 μM, these data can provide relevant information regarding the benefits of flavonoid-combined treatments of leukemia. All the three drugs exerted significant effects on DL. Our data are consistent with (1) the involvement of Complex I of the mitochondrial respiratory chain as an important source of delayed light emission on the 10 μs–10 ms scale, (2) the ability of superoxide anions to quench DL on the 100 μs–10 ms scale, probably via inhibition of reverse electron transfer at the Fe/S centers in Complex I, and (3) the relative insensitivity of DL to intracellular OH? and H2O2 levels. 相似文献
80.
Carole Ober Alex S. Nord Emma E. Thompson Lin Pan Zheng Tan Darren Cusanovich Ying Sun Raluca Nicolae Celina Edelstein Daniel H. Schneider Christine Billstrand Ditta Pfaffinger Natasha Phillips Rebecca L. Anderson Binu Philips Ramakrishnan Rajagopalan Thomas S. Hatsukami Mark J. Rieder Patrick J. Heagerty Deborah A. Nickerson Mark Abney Santica Marcovina Gail P. Jarvik Angelo M. Scanu Dan L. Nicolae 《Journal of lipid research》2009,50(5):798-806