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Rhodamine
Terms modified by Rhodamine Selected AbstractsJC-1, a sensitive probe for a simultaneous detection of P-glycoprotein activity and apoptosis in leukemic cellsCYTOMETRY, Issue 3 2006Driss Chaoui Abstract Background JC-1 probe has been successfully used for the analysis of either apoptosis or P-glycoprotein (P-gp) activity. Therefore, we wanted to see if JC-1 could also simultaneously assess both, P-gp activity and apoptosis, in acute myeloid leukemia (AML) cells. Methods P-gp activity was measured using JC-1 and compared to the results of the Rhodamine 123 (Rh 123) assay in P-gp negative and P-gp positive cell lines, and 12 AML samples. For apoptosis, spontaneous apoptosis, as well as, apoptosis induced by Cytosine Arabinosine and Homoharringtonine were analyzed. Both mitochondrial red fluorescence and cytoplasmic green fluorescence of JC-1 with and without a P-gp inhibitor (Cyclosporine A : CsA) were used for the identification of apoptotic cells, and this was compared to Annexin V/PI staining. Results (1) We found a good correlation between JC-1 and Rh 123 in viable cells. Even in a small population of viable cells, P-gp positive cells emitting low red fluorescence, gained on red fluorescence after P-gp inhibition with CsA permitting an evaluation of P-gp activity. (2) We found a good correlation between the Annexin V/PI staining and JC-1 (P < 0.0001) in the assessment of apoptotic cells. Most importantly, the apoptotic cells could be distinguished by the loss of red fluorescence and the increase of green fluorescence without any change after P-gp inhibition with CsA. Conclusions JC-1 can simultaneously evaluate two important parameters involved in drug resistance in AML cells, P-gp activity and apoptosis. © 2006 International Society for Analytical Cytology [source] Cover Picture: Electrophoresis 22'2008ELECTROPHORESIS, Issue 22 2008Article first published online: 26 NOV 200 Regular issues provide a wide range of research and review articles covering all aspects of electrophoresis. Here you will find cutting-edge articles on methods and theory, instrumentation, nucleic acids, CE and CEC, miniaturization and microfluidics, proteomics and two-dimensional electrophoresis. Selected topics of issue 22 are: Microfluidics: Applications for analytical purposes in chemistry and biochemistry ((http://doi.wiley.com/10.1002/elps.200800121)) Simultaneous laser-induced fluorescence and retro-reflected beam interference detection for CE ((http://doi.wiley.com/10.1002/elps.200800292)) Quantitative Proteomics by Fluorescent Labeling of Cysteine Residues using a Set of Two Cyanine-based or Three Rhodamine-based Dyes ((http://doi.wiley.com/10.1002/elps.200800092)) Chemometric resolution of fully overlapped capillary electrophoresis peaks: quantitation of carbamazepine in human serum in the presence of several interferences ((http://doi.wiley.com/10.1002/elps.200800400)) Identification of inorganic ions in post-blast explosive residues using portable capillary electrophoresis instrumentation and capacitively-coupled contactless conductivity detection ((http://doi.wiley.com/10.1002/elps.200800226)) [source] Pathogen-Mimicking MnO Nanoparticles for Selective Activation of the TLR9 Pathway and Imaging of Cancer Cells,ADVANCED FUNCTIONAL MATERIALS, Issue 23 2009Mohammed Ibrahim Shukoor Abstract Here, design of the first pathogen-mimicking metal oxide nanoparticles with the ability to enter cancer cells and to selectively target and activate the TLR9 pathway, and with optical and MR imaging capabilities, is reported. The immobilization of ssDNA (CpG ODN 2006) on MnO nanoparticles is performed via the phosphoramidite route using a multifunctional polymer. The multifunctional polymer used for the nanoparticle surface modification not only affords a protective organic biocompatible shell but also provides an efficient and convenient means for loading immunostimulatory oligonucleotides. Since fluorescent molecules are amenable to photodetection, a chromophore (Rhodamine) is introduced into the polymer chain to trace the nanoparticles in Caki-1 (human kidney cancer) cells. The ssDNA coupled nanoparticles are used to target Toll-like receptors 9 (TLR9) receptors inside the cells and to activate the classical TLR cascade. The presence of TLR9 is demonstrated independently in the Caki-1 cell line by western blotting and immunostaining techniques. The magnetic properties of the MnO core make functionalized MnO nanoparticles potential diagnostic agents for magnetic resonance imaging (MRI) thereby enabling multimodal detection by a combination of MR and optical imaging methods. The trimodal nanoparticles allow the imaging of cellular trafficking by different means and simultaneously are an effective drug carrier system. [source] Structure and signaling in polyps of a colonial hydroidINVERTEBRATE BIOLOGY, Issue 1 2004Neil W. Blackstone Abstract. After feeding, polyps of colonial hydroids contract regularly, dispersing food throughout the colony via the gastrovascular fluid. Such contractions may trigger signaling pathways that allow colonies to grow in an adaptive manner, i.e., to initiate development of more polyps in food-rich areas and to suppress polyp development in food-poor areas. In this context, we investigated the structure and potential signaling of the junction between polyps and stolons in colonies of the hydroid Podocoryna carnea. Using transmission electron microscopy, we found that the density of mitochondrion-rich epitheliomuscular cells was low in polyp and stolon tissues except at or near the polyp-stolon junction, where many of these mitochondrion-rich cells occur in ectodermal tissue. In vivo fluorescence microscopy suggests that these mitochondria are a principal source of the metabolic signals of the colony. Both native fluorescence of NAD(P)H and fluorescence from peroxides (visualized with H2DCFDA) co-localize to this region of the polyp. Rhodamine 123 fluorescence suggests that both these metabolic signals emanate from mitochondria. To test whether such metabolic signals may be involved in colony pattern formation, inbred lines of P. carnea were used. Colonies of a runner-like inbred line grow with widely spaced polyps and long stolonal connections, much like wild-type colonies in a food-poor environment. Colonies of a sheet-like inbred line grow with closely spaced polyps and short stolonal connections, similar to wild-type colonies in a food-rich environment. Polyp-stolon junctions in runner-like and sheet-like colonies were imaged for the fluorescence of H2DCFDA. Densitometric analysis of this signal indicates that the mitochondria in epitheliomuscular cells of runner-like polyps emit greater amounts of peroxides. Because peroxides and other reactive oxygen species are frequently intermediaries in metabolic signaling pathways, we suspect that such signaling may indeed occur at polyp-stolon junctions, affecting colony pattern formation in these inbred lines and possibly in hydroid colonies in general. [source] Cytokines alter the expression and activity of the multidrug resistance transporters in human hepatoma cell lines; analysis using RT-PCR and cDNA microarraysJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 11 2003Gigi Lee Abstract Pro-inflammatory cytokines suppress the hepatic expression of the multidrug resistance transporters in rodents, indicating potential usefulness in chemotherapy. Our objective was to investigate their impact in human hepatoma cells. HuH 7 and HepG2 cells were treated with IL-1,, IL-6, or TNF-, for 0,72 h. Expression and activity of MDR1 and the MRP (MRP1, 2, 3, and 6) transporters were examined by RT-PCR, efflux assays, and microarrays. Significant reductions in the MDR1-mediated efflux of Rhodamine 123 and MDR1 mRNA levels were observed in HuH 7 cells treated with IL-6, TNF-,, or IL-1, and in TNF-,,treated HepG2 cells. However, cytokine-treated HuH7 cells also demonstrated 1.6- to 2.6-fold greater efflux of the MRP substrate, 5-carboxyfluorescein (5-CF) and higher MRP3 mRNA levels (p,<,0.05). IL-1, and IL-6 treatments increased MRP activity and MRP1 mRNA levels in HepG2 cells (p,<,0.05). Microarrays studies performed in IL-6 and TNF-,,treated HepG2 cells detected similar changes in the expression of the MDR1 and MRP transporters, but this did not reach significance. However, the microarrays confirmed cytokine-mediated induction of several acute phase proteins. Our data suggests that although cytokine-mediated suppression of PGP may alter drug resistance in malignant cells, these cytokines may also impose an induction in other multidrug resistance genes. © 2003 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 92:2152,2163, 2003 [source] Energy Transfer from Chemically Attached Rhodamine 101 to Adsorbed Methylene Blue on Microcrystalline Cellulose Particles,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 3 2007Hernán B. Rodríguez Rhodamine 101 (R101) was chemically attached onto microcrystalline cellulose and methylene blue (MB) was adsorbed to a sample bearing nearby 6 × 10,7 mol R101 (g cellulose),1. The system was studied by reflectance and emission spectroscopy in the solid state. R101 shows no aggregation in these conditions and, while pure MB builds up dimers on cellulose even at 2 × 10,8 mol g,1, in the presence of R101 no evidence on selfaggregation or heteroaggregation is found up to around 10,6 mol g,1. No exciplex formation is found as well. The overall fluorescence quantum yield measured on thick layers, once re-absorption effects are accounted for, amounts to 0.80 ± 0.07 for pure R101 and decreases steadily on increasing the concentration of MB. Results demonstrate the occurrence of radiative and nonradiative singlet energy transfer from R101 to MB. For thick layers of particles, the combined effect of both kinds of energy transfer amounts to nearly 80% at the highest acceptor concentration, while nonradiative transfer reaches 60% both for thin and optically thick layers. The dependence of nonradiative energy transfer efficiencies on the acceptor concentration is analyzed and the origin of departures from Förster behavior at low acceptor concentration is discussed. [source] Titelbild: Rhodamine,NN: eine neue Klasse maskierter Fluoreszenzfarbstoffe (Angew. Chem.ANGEWANDTE CHEMIE, Issue 20 201020/2010) Der photoaktivierbare Fluoreszenzfarbstoff ,, der Rhodamin-NN-Klasse, dessen Struktur auf dem Titelbild gezeigt ist, wurde in einem Mikroskopieschema zur Darstellung von Zellbestandteilen wie Peroxisomen, Aktin und Mikrotubuli mit zwei weiteren maskierten Fluorophoren mit ähnlichen spektralen Eigenschaften kombiniert. Das Schema, das nur einen Anregungs- und einen Detektionskanal verwendet, beruht auf einer schrittweisen Aktivierung und Detektion der Farbstoffe. Synthese und Eigenschaften von Rhodamin-NN-Derivaten werden in der Zuschrift von V.,N. Belov et,al. auf S.,3598,ff. beschrieben (Bild: H. Sebesse, MPI für biophysikalische Chemie, Göttingen). [source] Rhodamine,NN: eine neue Klasse maskierter Fluoreszenzfarbstoffe,ANGEWANDTE CHEMIE, Issue 20 2010Vladimir Strahlende Zukunft: Die Reaktion von Diazomethan mit N,N,N,,N,-Tetraalkylrhodamin-Säurechloriden führt zu 2-Diazo-2,3-dihydro-1H -indenspiro[1,9,]-9H- xanthen-3-onen als einer neuen Klasse maskierter Rhodamine. Diese Farbstoffe ermöglichen neue Mikroskoskopieverfahren, die auf der stufenweisen Aktivierung und Detektion unterschiedlicher Fluoreszenzmarker beruhen (siehe Bild). [source] Direct current decreases cell viability but not P-glycoprotein expression and function in human multidrug resistant leukemic cellsBIOELECTROMAGNETICS, Issue 7 2001Carla Holandino Abstract Inhibition of tumor growth induced by treatment with direct current (DC) has been reported in several systems. In the current work, the cellular effects generated by the DC treatment of the human leukemic K562 cell line and its vincristine-resistant derivative K562-Lucena 1 were analyzed by trypan blue staining and transmission electron microscopy. DC stimulation induced cell lysis, alterations in shape, membrane extraction or discontinuity, and intense vacuolization of some cells. In addition, treatment of K562 and K562-Lucena 1 cells caused a marked decrease in viability. Since multidrug resistance is a major factor contributing with failure of chemotherapy in many tumors, the expression and function of P-glycoprotein (P-gp) in K562-Lucena 1 cells were also studied. The expression of mdr1, the gene encoding P-gp, was analyzed by reverse transcription polymerase chain reaction, which showed that this gene was equally expressed in either treated or untreated cells. These results were confirmed by flow cytometry with a monoclonal anti P-gp antibody and the Rhodamine 123 extrusion method, which revealed that P-gp surface expression and function were unaltered after DC treatment. Our results suggest that DC treatment does not affect P-gp in human leukemic cells, but affects their viability by mechanisms that would involve clear cellular effects, but also additional targets, whose relevance in dc treated tumoral cells is currently discussed. Bioelectromagnetics 22:470,478, 2001. © 2001 Wiley-Liss, Inc. [source] Mitochondrial Membrane Potential Selects Hybridomas Yielding High Viability in Fed-Batch CulturesBIOTECHNOLOGY PROGRESS, Issue 1 2002Brian D. Follstad Prior research (Follstad, B. D.; Wang, D. I. C.; Stephanopoulos, G. Mitochondrial membrane potential differentiates cells resistant to apoptosis in hybridoma cultures. Eur. J. Biochem. 2000, 267, 6534,6540.) identified mitochondrial membrane potential (MMP) as a marker of hybridoma subpopulations resistant to apoptosis caused by a variety of apoptosis inducers. In this study, we investigated the viability of hybridoma cell cultures inoculated with cells of varying MMP in regular fed-batch operation. A hybridoma cell population was separated using FACS into subpopulations based on their mean mitochondrial membrane potential (MMP) as measured using the common mitochondrial stain, Rhodamine 123 (Rh123). These subpopulations showed dramatic differences in their apoptotic death kinetics. Fed-batches inoculated with a high MMP subpopulation reached higher viable cell concentrations and viabilities that were maintained for prolonged periods of time relative to fed-batches inoculated with low MMP subpopulations. These results underline the heterogeneous nature of hybridoma cell cultures and suggest that mitochondrial physiology is a critical parameter determining culture performance. [source] ChemInform Abstract: Design and Synthesis of Rhodamine 110 Derivative and Caspase-3 Substrate for Enzyme and Cell-Based Fluorescent AssayCHEMINFORM, Issue 18 2001Sui Xiong Cai Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] A Comparison Study of Rhodamine,B Photodegradation over Nitrogen-Doped Lamellar Niobic Acid and Titanic Acid under Visible-Light IrradiationCHEMISTRY - A EUROPEAN JOURNAL, Issue 14 2009Xiukai Li Dr. Abstract Slip between the sheets! The intercalation properties of lamellar solid acids have a profound impact on nitrogen doping as well as on the resultant visible-light photocatalysis, and the effects depend strongly on the protonic acidities of the samples (see figure). A solid-state reaction method with urea as a nitrogen precursor was used to prepare nitrogen-doped lamellar niobic and titanic solid acids (i.e., HNb3O8 and H2Ti4O9) with different acidities for visible-light photocatalysis. The photocatalytic activities of the nitrogen-doped solid acids were evaluated for rhodamine,B (RhB) degradation and the results were compared with those obtained over the corresponding nitrogen-doped potassium salts. Techniques such as XRD, BET, SEM, X-ray photoelectron spectroscopy, and UV-visible diffuse reflectance spectroscopy were adopted to explore the nature of the materials as well as the characteristics of the doped nitrogen species. It was found that the intercalation of the urea precursor helped to stabilize the layered structures of both lamellar solid acids and enabled easier nitrogen doping. The effects of urea intercalation were more significant for the more acidic HNb3O8 sample than for the less acidic H2Ti4O9. Compared with the nitrogen-doped KNb3O8 and K2Ti4O9 samples, the nitrogen-doped HNb3O8 and H2Ti4O9 solid acids absorb more visible light and exhibit a superior activity for RhB photodegradation under visible-light irradiation. The nitrogen-doped HNb3O8 sample performed the best among all the samples. The results of the current study suggest that the protonic acidity of the lamellar solid-acid sample is a key factor that influences nitrogen doping and the resultant visible-light photocatalysis. [source] Fluorophores as Optical Sensors for Local Forces,CHEMPHYSCHEM, Issue 12 2009Stefan Marawske Abstract The main aim of this study is to investigate correlations between the impact of an external mechanical force on the molecular framework of fluorophores and the resultant changes in their fluorescence properties. Taking into account previous theoretical studies, we designed a suitable custom-tailored oligoparaphenylenevinylene derivative (OPV5) with a twisted molecular backbone. Thin foils made of PVC doped with 100 nM OPV were prepared. By applying uniaxial force, the foils were stretched and three major optical effects were observed simultaneously. First, the fluorescence anisotropy increased, which indicates a reorientation of the fluorophores within the matrix. Second, the fluorescence lifetime decreased by approximately 2.5,% (25 ps). Finally, we observed an increase in the emission energy of about 0.2,% (corresponding to a blue-shift of 1.2 nm). In addition, analogous measurements with Rhodamine 123 as an inert reference dye showed only minor effects, which can be attributed to matrix effects due to refractive index changes. To relate the observed spectroscopic changes to the underlying changes in molecular properties, quantum-chemical calculations were also performed. Semiempirical methods had to be used because of the size of the OPV5 chromophore. Two conformers of OPV5 (C2 and Cisymmetry) were considered and both gave very similar results. Both the observed blue-shift of fluorescence and the reduced lifetime of OPV5 under tensile stress are consistent with the results of the semiempirical calculations. Our study proves the feasibility of fluorescence-based local force probes for polymers under tension. Improved optical sensors of this type should in principle be able to monitor local mechanical stress in transparent samples down to the single-molecule level, which harbors promising applications in polymer science and nanotechnology. [source] Assessment of Joule heating and its effects on electroosmotic flow and electrophoretic transport of solutes in microfluidic channelsELECTROPHORESIS, Issue 3 2006Gongyue Tang Abstract Joule heating is inevitable when an electric field is applied across a conducting medium. It would impose limitations on the performance of electrokinetic microfluidic devices. This article presents a 3-D mathematical model for Joule heating and its effects on the EOF and electrophoretic transport of solutes in microfluidic channels. The governing equations were numerically solved using the finite-volume method. Experiments were carried out to investigate the Joule heating associated phenomena and to verify the numerical models. A rhodamine,B-based thermometry technique was employed to measure the solution temperature distributions in microfluidic channels. The microparticle image velocimetry technique was used to measure the velocity profiles of EOF under the influence of Joule heating. The numerical solutions were compared with experimental results, and reasonable agreement was found. It is found that with the presence of Joule heating, the EOF velocity deviates from its normal "plug-like" profile. The numerical simulations show that Joule heating not only accelerates the sample transport but also distorts the shape of the sample band. [source] Effect of preoperative prophylaxis with filgrastim in cancer neck dissectionEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 5 2000Wenisch Background Cancer surgery is known to lead to a deterioration in host defence mechanisms and an increase in susceptibility to infection after operation. Filgrastim enhances important antimicrobial functions of neutrophils including chemotaxis, phagocytosis and oxidative killing mechanisms. Methods The effects of additional (all patients received perioperative 3 , 25 mg kg,1 cefotiam and 1 , 20 mg kg,1 metronidazole) preoperative prophylaxis with filgrastim (5 ,g kg,1 12 h prior to surgery plus 5 ,g kg,1 0 h prior to surgery) on neutrophil phagocytosis and reactive oxygen radical production and postoperative infections in 24 patients undergoing cancer neck dissection were studied. Phagocytic capacity was assessed by measuring the uptake of fluorescein isothiocyanate-labelled Escherichia coli and Staphylococcus aureus by flow cytometry. Reactive oxygen generation after phagocytosis was estimated by determining the amount of dihydrorhodamine 123 converted to rhodamine 123, intracellularly. Results In the filgrastim-treated patients a higher neutrophil phagocytic capacity was seen intraoperatively, and 1,5 days postoperative, but not prior to surgery. Reactive oxygen radical production was significantly higher in filgrastim-treated patients prior to surgery, intraoperative and postoperative (1,5 days). 2/12 (17%) patients had postoperative infections in the filgrastim group and 9/12 (75%) patients had infections in the placebo group (P < 0.001). In particular, wound infections were recorded more often in the placebo group (1/12 vs. 6/12; P = 0.004). Conclusion We conclude that filgrastim enhances perioperative neutrophil function and could be useful in the prophylaxis of postoperative wound infections in patients undergoing cancer neck dissection. [source] Materials for a Reliable Solid-State Dye Laser at the Red Spectral EdgeADVANCED FUNCTIONAL MATERIALS, Issue 16 2009Inmaculada Garcia-Moreno Abstract In the search to extend the tuning range of solid-state dye lasers (SSDLs) to the red-edge spectral region, new photosensitive materials have been designed and synthesized based on six commercial dyes (sulforhodamine B, perylene red, rhodamine 640, LDS698, LDS722, and LDS730) incorporated into different linear, crosslinked, fluorinated, and sililated polymeric matrices. Under transversal pumping at 532,nm, these materials exhibit highly efficient, stable, as well as wavelength-tunable laser action from the visible-to-NIR spectral region (575,750,nm). The lasing performance of the materials doped with perylene and xanthene dyes is, to the best of our knowledge, the highest achieved to date for these chromophores when incorporated into organic, inorganic, or hybrid matrices. Regarding the LDS derivatives, this is the first time that laser action from these dyes in solid-state media is reported. These particular characteristics have impelled the building of the first prototype SSDL that is compact, versatile, and easy to handle. [source] Red,Yellow Fluorescence Patterning of a Polymer Film Containing Phthalimido Carbamate GroupsADVANCED FUNCTIONAL MATERIALS, Issue 17 2007H. Chae Abstract Bicolor fluorescent micro-patterns in the polymer film are prepared through the use of a new group of photobase generator containing phthalimido carbamate groups. The photobase generation from phthalimide carbamates is studied by examining the changes in pH, fluorescence intensity, and photo-crosslinking of poly(glycidyl methacrylate). The product analysis of a model compound indicates that amine groups are produced from the photolytic cleavage of the C,N bond of the phthalimide carbamate groups. A copolymer containing phthalimide carbamate groups is applied to a bicolor fluorescent imaging material. Red-yellow fluorescent micropatterns are obtained by treating the copolymer film, which is irradiated with 254 nm UV light through a photomask, with fluorescamine and rhodamine, consecutively. Various colored fluorescent micropatterns , green, red, or red-yellow, are obtained on a single polymer film by varying the excitation wavelength. [source] Formation of Gold and Silver Nanoparticle Arrays and Thin Shells on Mesostructured Silica Nanofibers,ADVANCED FUNCTIONAL MATERIALS, Issue 16 2007S. Zhang Abstract Mesostructured silica nanofibers synthesized in high yields with cetyltrimethylammonium bromide as the structure-directing agent in HBr solutions are used as templates for the assembly of Au and Ag nanoparticles and the formation of thin Au shells along the fiber axis. Presynthesized spherical Au and Ag nanoparticles are adsorbed in varying amounts onto the silica nanofibers through bifunctional linking molecules. Nonspherical Au nanoparticles with sharp tips are synthesized on the nanofibers through a seed-mediated growth approach. The number density of nonspherical Au nanoparticles is controlled by varying the amount of seeded nanofibers relative to the amount of supplied Au precursor. This seed-mediated growth is further used to form continuous Au shells around the silica nanofibers. Both the Au- and Ag-nanoparticle/silica-nanofiber hybrid nanostructures and silica/Au core/shell fibers exhibit extinction spectra that are distinct from the spectra of Au and Ag nanoparticles in solution, indicating the presence of new surface plasmon resonance modes in the silica/Au core/shell fibers and surface plasmon coupling between closely spaced metal nanoparticles assembled on silica nanofibers. Spherical Au- and Ag-nanoparticle/silica-nanofiber hybrid nanostructures are further used as substrates for surface-enhanced Raman spectroscopy, and the enhancement factors of the Raman signals obtained on the Ag-nanoparticle/silica-nanofiber hybrid nanostructures are 2,×,105 for 4-mercaptobenzoic acid and 4-mercaptophenol and 7,×,107 for rhodamine,B isothiocyanate. These hybrid nanostructures are therefore potentially useful for ultrasensitive chemical and biological sensing by using molecular vibrational signatures. [source] Matrine improves 17,-ethinyl estradiol-induced acute cholestasis in ratsHEPATOLOGY RESEARCH, Issue 11 2009Ying Zhao Aim:, To explore the effects of matrine (MT) on acute intrahepatic cholestasis induced by 17,-ethinyl estradiol (EE) in rats. Methods:, Acute intrahepatic cholestasis in rats were induced by EE, and the effects of MT on acute intrahepatic cholestasis were explored and compared with ursodeoxycholic acid (UDCA) by serum biochemical determination and bile excretion experiments. Results:, The serum biochemical and bile biochemical results indicated that MT and UDCA had notable hepatoprotective effects by counteracting cholestasis induced by EE. The bile flow and the bile excretion of glycocholic acid (GC, a substrate of bile salt export pump [Bsep]), ketoprofen glucuronide (KPG) and rhodamine 123 (Rh123, a substrate of multidrug resistance protein 1 [MDR1]) decreased by EE, were significantly improved after administration of MT. Conclusion:, MT exhibited potential protection against EE-induced acute intrahepatic cholestasis. [source] Type, extent and use of colours in ready-to-eat (RTE) foods prepared in the non-industrial sector , a case study from Hyderabad, IndiaINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 2 2004Padmaja R. Jonnalagadda Summary The type and extent of colours added to ready-to-eat (RTE) foods prepared in the non-industrial sector of India was investigated. Of the 545 RTE foods analysed, 90% contained permitted colours, 2% contained a combination of permitted and non-permitted colours and 8% contained only non-permitted colours. However in RTE foods with permitted colours, 73% exceeded 100 ppm, as prescribed by the Prevention of Food Adulteration Act of India, and 27% were within the prescribed levels. Among the permitted colours, tartrazine was the most widely used colour followed by sunset yellow. The maximum concentration of colours was detected in sweet meats (18 767 ppm), non-alcoholic beverages (9450 ppm), miscellaneous foods (6106 ppm) and hard-boiled sugar confectioneries (3811 ppm). Among the non-permitted colours found, rhodamine was most commonly used. Some of the foods, such as savouries and miscellaneous foods like sugar coated aniseed and almond milk, are not supposed to contain colours as per the Prevention of Food Adulteration Act, but were found to contain colours. [source] Three-dimensional imaging of human skin and mucosa by two-photon laser scanning microscopyJOURNAL OF CUTANEOUS PATHOLOGY, Issue 8 2002Janine C. Malone Background: Various structural components of human skin biopsy specimens are difficult to visualize using conventional histologic approaches. Methods: We used two-photon microscopy and advanced imaging software to render three-dimensional (3D) images of in situ nerves, blood vessels, and hair follicles labeled with various fluorescent markers. Archived frozen human skin biopsy specimens were cryosectioned up to 150 µm in thickness and fluorescently stained with rhodamine- or fluorescein-labeled antibodies or lectins. Optical sections were collected by two-photon microscopy and the resulting data sets were analyzed in three dimensions using Voxx software. Results: Reconstructed image volumes demonstrated the complex 3D morphology of nerves, blood vessels and adnexal structures in normal mucocutaneous tissue. Conclusion: Two-photon microscopy and Voxx rendering software allow for detailed 3D visualization of structures within human mucocutaneous biopsy specimens, as they appear in situ, and facilitate objective interpretation of variations in their morphology. These techniques may be used to investigate disorders involving cutaneous structures that are difficult to visualize by means of traditional microscopy. [source] Anoxia leads to a rapid translocation of human trypsinogen 4 to the plasma membrane of cultured astrocytesJOURNAL OF NEUROCHEMISTRY, Issue 2 2010Krisztián Tárnok J. Neurochem. (2010) 115, 314,324. Abstract Trypsinogen 4 is specifically expressed in the human brain, mainly by astroglial cells. Although its exact role in the nervous tissue is yet unclear, trypsin 4-mediated pathological processes were suggested in Alzheimer's disease, multiple sclerosis and ischemic injury. In the present study, we analyzed the intracellular distribution of fluorescently tagged human trypsinogen 4 isoforms during normal and anoxic conditions in transfected mouse primary astrocytes. Our results show that initiation of anoxic milieu by the combined action of KCN treatment and glucose deprivation rapidly leads to the association of leader peptide containing trypsinogen 4 constructs to the plasma membrane. Using rhodamine 110 bis-(CBZ-L-isoleucyl-L-prolyl-L-arginine amide), a synthetic chromogen peptide substrate of trypsin, we show that anoxia can promote extracellular activation of trypsinogen 4 indicating that extracellular activation of human trypsinogen 4 can be an important component in neuropathological changes of the injured human brain. [source] The human brain endothelial cell line hCMEC/D3 as a human blood-brain barrier model for drug transport studiesJOURNAL OF NEUROCHEMISTRY, Issue 5 2008Birk Poller Abstract The human brain endothelial capillary cell line hCMEC/D3 has been developed recently as a model for the human blood-brain barrier. In this study a further characterization of this model was performed with special emphasis on permeability properties and active drug transport. Para- or transcellular permeabilities (Pe) of inulin (0.74 × 10,3 cm/min), sucrose (1.60 × 10,3 cm/min), lucifer yellow (1.33 × 10,3 cm/min), morphine (5.36 × 10,3 cm/min), propranolol (4.49 × 10,3 cm/min) and midazolam (5.13 × 10,3 cm/min) were measured. By addition of human serum the passive permeability of sucrose could be reduced significantly by up to 39%. Furthermore, the expression of a variety of drug transporters (ABCB1, ABCG2, ABCC1,5) as well as the human transferrin receptor was demonstrated on the mRNA level. ABCB1, ABCG2 and transferrin receptor proteins were detected and functional activity of ABCB1, ABCG2 and the ABCC family was quantified in efflux experiments. Furthermore, ABCB1-mediated bidirectional transport of rhodamine 123 was studied. The transport rate from the apical to the basolateral compartment was significantly lower than that in the inverse direction, indicating directed p-glycoprotein transport. The results of this study demonstrate the usefulness of the hCMEC/D3 cell line as an in vitro model to study drug transport at the level of the human blood-brain barrier. [source] Thyroid hormone enhances transected axonal regeneration and muscle reinnervation following rat sciatic nerve injuryJOURNAL OF NEUROSCIENCE RESEARCH, Issue 8 2010Petrica-Adrian Panaite Abstract Improvement of nerve regeneration and functional recovery following nerve injury is a challenging problem in clinical research. We have already shown that following rat sciatic nerve transection, the local administration of triiodothyronine (T3) significantly increased the number and the myelination of regenerated axons. Functional recovery is a sum of the number of regenerated axons and reinnervation of denervated peripheral targets. In the present study, we investigated whether the increased number of regenerated axons by T3-treatment is linked to improved reinnervation of hind limb muscles. After transection of rat sciatic nerves, silicone or biodegradable nerve guides were implanted and filled with either T3 or phosphate buffer solution (PBS). Neuromuscular junctions (NMJs) were analyzed on gastrocnemius and plantar muscle sections stained with rhodamine ,-bungarotoxin and neurofilament antibody. Four weeks after surgery, most end-plates (EPs) of operated limbs were still denervated and no effect of T3 on muscle reinnervation was detected at this stage of nerve repair. In contrast, after 14 weeks of nerve regeneration, T3 clearly enhanced the reinnervation of gastrocnemius and plantar EPs, demonstrated by significantly higher recovery of size and shape complexity of reinnervated EPs and also by increased acetylcholine receptor (AChRs) density on post synaptic membranes compared to PBS-treated EPs. The stimulating effect of T3 on EP reinnervation is confirmed by a higher index of compound muscle action potentials recorded in gastrocnemius muscles. In conclusion, our results provide for the first time strong evidence that T3 enhances the restoration of NMJ structure and improves synaptic transmission. © 2010 Wiley-Liss, Inc. [source] The increase in the frequency of MICA gene A6 allele in oral squamous cell carcinomaJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 6 2002Liu Chung-Ji Abstract Background: Oral squamous cell carcinoma (OSCC) was reported to be associated with immune function. The MICA (MHC class I chain-related gene A) is expressed by keratinocytes and other epithelial cells, and its encoded protein interacts with ,/, T cells localized in submucosa. The MICA also influences the heat shock protein function. We speculated that the alterations of MICA might influence the pathogenesis of OSCC through the aberration in presenting tumor antigens or heat shock protein. MICA gene has a triplet repeat (GCT) polymorphism in the transmembrane domain, resulting in five distinctive allelic patterns. Methods: We analysed this MICA polymorphism in 67 OSCC patients and 351 randomly selected unrelated controls. By using the ABI Prism 377,18 DNA sequencer (Applied Biosystems, Foster City, CA, USA) to analyse the sample DNA PCR products. The number of micro-satellite repeats was estimated with Genescan 672 software (Applied Biosystems) with a standard size marker of GS-350 TAMRA (N,N,N,N-tetramethyl-6-carbohydroxyl rhodamine; Applied Biosystems). Results: The phenotype frequency of allele A6 of MICA in subjects with OSCC was significantly higher than that in controls (RR = 3.46, 95% CI = 1.73,6.94, P = 0.0002), as was the frequency of allele (RR = 2.64, 95% CI = 1.39,5.02, P = 0.002). Conclusion: The results suggest that allele A6 in MICA might confer the risk of OSCC. [source] Methoxypolyethylene glycol- block -polycaprolactone diblock copolymers reduce P-glycoprotein efflux in the absence of a membrane fluidization effect while stimulating P-glycoprotein ATPase activityJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 4 2007Jason Zastre Abstract We have previously shown that amphiphilic diblock copolymers composed of methoxypolyethylene glycol- b -polycaprolactone (MePEG- b -PCL) increased the cellular accumulation and reduced the basolateral to apical flux of the P-glycoprotein substrate, rhodamine 123 (R-123) in caco-2 cells. The purpose of this study was to investigate membrane perturbation effects of MePEG- b -PCL diblock copolymers with erythrocyte membranes and caco-2 cells and the effect on P-gp ATPase activity. The diblock copolymer MePEG17 -b-PCL5 induced increasing erythrocyte hemolysis at concentrations which correlated with increasing accumulation of R-123 into caco-2 cells. However, no increase in cellular accumulation of R-123 by non-P-gp expressing cells was observed, suggesting that diblock did not enhance the transmembrane passive diffusion of R-123, but that the accumulation enhancement effect of the diblock in caco-2 cells was likely mediated primarily via P-gp inhibition. Fluorescence anisotropy measurements of membrane fluidity and P-gp ATPase activity demonstrated that MePEG17 - b -PCL5 decreased caco-2 membrane fluidity while stimulating ATPase activity approximately threefold at concentrations that maximally enhanced R-123 caco-2 accumulation. These results suggest that inhibition of P-gp efflux by MePEG17 - b -PCL5 does not appear to be related to increases in membrane fluidity or through inhibition in P-gp ATPase activities, which are two commonly reported cellular effects for P-gp inhibition mediated by surfactants. © 2006 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 96: 864,875, 2007 [source] The role of surfactants in the reversal of active transport mediated by multidrug resistance proteinsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 6 2003Katrijn Bogman Abstract A variety of seven nonionic, one amphoteric and, one anionic surfactant that are applied or investigated as surfactants in drug formulation, were analyzed for their capacity to modulate carrier-mediated transport by efflux pumps. Two cell lines, murine monocytic leukemia cells overexpressing P-glycoprotein (P-gp) and Madin-Darby canine kidney cells stably overexpresssing human multidrug resistance-associated protein 2 (MRP2), were used as test systems. The modulation of P-gp and of MRP2 function was studied by the reversal of rhodamine 123 and of methylfluorescein-glutathione conjugate transport, respectively. Mechanisms that were not transporter related and could lead to misinterpretations were identified, such as probe quenching, probe encapsulation by micelles, and membrane damage. P-gp-mediated rhodamine 123 transport was inhibited by five nonionic surfactants in a concentration-dependent manner and in the order TPGS,>,Pluronic PE8100,>,Cremophor EL,>,Pluronic PE6100,,,Tween 80. In contrast, none of the surfactants showed a significant inhibition of MRP2-mediated efflux in Madin-Darby canine kidney/MRP2 cells. In conclusion, the results indicate that surfactants demonstrate a transporter-specific interaction, rather than unspecific membrane permeabilization. The present analysis offers insight in the possible mechanisms of surfactant interactions with biological membranes and could help to identify specific drug formulations. © 2003 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 92:1250,1261, 2003 [source] Effects of myricetin, an antioxidant, on the pharmacokinetics of losartan and its active metabolite, EXP-3174, in rats: possible role of cytochrome P450 3A4, cytochrome P450 2C9 and P-glycoprotein inhibition by myricetinJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 7 2010Dong-Hyun Choi Abstract Objectives, The effects of myricetin, a natural flavonoid, on the pharmacokinetics of losartan and its active metabolite, EXP-3174, were investigated in rats. Losartan and myricetin interact with cytochrome P450 (CYP) enzymes and P-glycoprotein, and the increase in the use of health supplements may result in myricetin being taken concomitantly with losartan as a combination therapy to treat or prevent cardiovascular diseases. Methods, The pharmacokinetic parameters of losartan and EXP-3174 were determined after oral administration of losartan (9 mg/kg) to rats in the presence or absence of myricetin (0.4, 2 and 8 mg/kg). The effects of myricetin on P-glycoprotein as well as CYP3A4 and CYP2C9 activity were also evaluated. Key findings, Myricetin inhibited CYP3A4 and CYP2C9 enzyme activity with a 50% inhibition concentration of 7.8 and 13.5 µm, respectively. In addition, myricetin significantly enhanced the cellular accumulation of rhodamine 123 in MCF-7/ADR cells overexpressing P-glycoprotein in a concentration-dependent manner. The pharmacokinetic parameters of losartan were significantly altered by myricetin compared with the control. The presence of myricetin (2 or 8 mg/kg) increased the area under the plasma concentration,time curve of losartan by 31.4,61.1% and peak plasma concentration of losartan by 31.8,50.2%. Consequently, the absolute bioavailability of losartan in the presence of myricetin increased significantly (P < 0.05, 2 mg/kg; P < 0.01, 8 mg/kg) compared with the control. There was no significant change in the time to reach the peak plasma concentration, apparent volume of distribution at steady state or terminal half-life of losartan in the presence of myricetin. Furthermore, concurrent use of myricetin (8 mg/kg) significantly decreased the metabolite,parent area under the plasma concentration,time curve ratio by 20%, implying that myricetin may inhibit the CYP-mediated metabolism of losartan to its active metabolite, EXP-3174. Conclusions, The enhanced bioavailability of losartan may be mainly due to inhibition of the CYP3A4- and CYP2C9-mediated metabolism of losartan in the small intestine or in the liver, and the P-glycoprotein efflux pump in the small intestine by myricetin. [source] CJY, an isoflavone, reverses P-glycoprotein-mediated multidrug-resistance in doxorubicin-resistant human myelogenous leukaemia (K562/DOX) cellsJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 7 2007Bian-Sheng Ji In an effort to develop safe and effective multidrug-resistance (MDR) reversing agents, the effect of CJY, an isoflavone, on the P-glycoprotein (P-gp) function and P-gp-mediated MDR was evaluated in doxorubicin-resistant human myelogenous leukaemia (K562/DOX) cells. The results showed that CJY caused a marked increase in accumulation and a notable decrease in efflux of rhodamine 123 (Rh123). The inhibitory effect of the agent on P-gp function persisted for at least 120 min after removal of 2.5 ,M CJY from the incubation medium. The doxorubicin-induced cytotoxicity, apoptosis and cell cycle perturbations were significantly potentiated by CJY. The intracellular accumulation of doxorubicin was also enhanced. The compound exhibited potent effects in-vitro on the reversal of P-gp-mediated MDR, suggesting that it could become a candidate as an effective MDR reversing agent in cancer chemotherapy. [source] Catalytic resonance scattering spectral determination of ultratrace horseradish peroxidase using rhodamine SLUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 3 2009Zhiliang Jiang Abstract A highly sensitive and selective resonance scattering spectral assay was proposed for the determination of horseradish peroxidase (HRP), based on its catalytic effect on the H2O2 oxidation of KI to form I3,. The I3, combined respectively with rhodamine (Rh) dye such as rhodamine S (RhS), rhodamine 6G (Rh6G), rhodamine B (RhB) and butyl-rhodamine B (b-RhB), to form association particles (Rh-I3)n. The four Rh systems all exhibit a stronger resonance scattering (RS) peak at 424 nm. For the RhS, Rh6G, RhB and b-RhB systems, HRP concentration in the range of 3.2 × 10,12 to 4.8 × 10,9, 2 × 10,11 to 3.2 × 10,9, 1.6 × 10,11 to 3.2 × 10,9 and 1.6 × 10,11 to 4 × 10,9 g/mL was linear to its RS intensity at 424 nm, with a detection limit of 2.2 × 10,12, 2.5 × 10,12, 4.4 × 10,12 and 2.6 × 10,12 g/mL, respectively. This RhS system was most sensitive and stable, and was applied for the determination of HRP in the hepatitis B surface antibody labeling HRP and water samples, with satisfactory results. Copyright © 2009 John Wiley & Sons, Ltd. [source] | ||||||||||||||||