Search results for "Rhodamines"
showing 10 items of 36 documents
Oxidative metabolism in a rat hepatoma (N13) and isolated rat hepatocytes: A flow cytometric comparative study
1996
Recently, we have developed a new and fast kinetic method for assessing mitochondrial membrane potential by flow cytometry, based on the quantitation of the initial rate of rhodamine 123 (Rh123) uptake by living cells. This test has proved suitable to detect metabolic and toxic effects on mitochondria. To characterize energy metabolism in a rat hepatoma cell line (N13), we applied this method to assess several metabolic pathways that eventually generate mitochondrial membrane potential. Using this approach, we found that N13 hepatoma cells retain an oxidative capacity comparable with that observed in isolated hepatocytes under the same conditions. These results show that this cell line may …
Modulation of hippocampal theta oscillations and spatial memory by relaxin-3 neurons of the nucleus incertus.
2009
Hippocampal theta rhythm is thought to underlie learning and memory, and it is well established that “pacemaker” neurons in medial septum (MS) modulate theta activity. Recent studies in the rat demonstrated that brainstem-generated theta rhythm occurs through a multisynaptic pathway via the nucleus incertus (NI), which is the primary source of the neuropeptide relaxin-3 (RLN3). Therefore, this study examined the possible contribution of RLN3 to MS activity, and associated hippocampal theta activity and spatial memory. In anesthetized and conscious rats, we identified the ability of intraseptal RLN3 signaling to modulate neuronal activity in the MS and hippocampus and promote hippocampal the…
Ascending projections from the optic tectum in the lizard Podarcis hispanica.
1998
The ascending projections of the optic tectum, including their cells of origin, have been studied in the lizard Podarcis hispanica by means of a two-step experimental procedure. First, tracers were injected in the tectum to study the anterograde labeling in the forebrain. Second, the cells of origin of these projections have been identified by analyzing the retrograde labeling after tracer injections in the thalamus, hypothalamus, and pretectum. Three main tectal ascending pathways have been described: the dorsal tecto-thalamic tract (dtt), the medial tecto-thalamic tract (mtt), and the ventral tecto-thalamic tract (vtt). The dtt originates in radial cells of layers 5 and 7 and bipolar cell…
Contact sensitizers modulate mechanisms of receptor-mediated endocytosis but not fluid-phase endocytosis in murine epidermal Langerhans cells.
1995
In order to define the influence of contact allergens on the fluid-phase endocytosis (FPE) of soluble molecules of murine epidermal Langerhans cells (LC), we studied the internalization of FITC-labeled bovine serum albumin (FITC-BSA), TRITC-labeled dextrane (TRITC-DEX) as well as horseradish peroxidase by LC. A 3-parameter flow-cytometric technique was performed for quantification of internalized FITC-BSA in LC using quantum red-labeled reagents for detection of la-antigen expression by LC and propidium iodide for exclusion of dead cells from analysis. A temperature-dependent rapid accumulation of FITC-BSA was noticed in time-course studies reaching a plateau between 1 and 2 h of in vitro c…
Laser fragmentation of pancreatic duct stones using a rhodamine laser with an automatic stone-tissue detection system. Basic in-vitro studies
1997
OBJECTIVES The aim of our study was to examine the suitability of a rhodamine 6G laser with an integrated stone-tissue detection system (STDS) for fragmenting pancreatic stones. METHODS A total of 64 pancreatic duct stones were measured for weight, diameter, main chemical components and in some cases for their computerized tomography density. Recognition of all stones was checked with the standard STDS or a prototype version. Number of fragmentation pulses, total fragmentation energies and correlation with the individual stone parameters were determined. The quality of the tissue-detection mode was evaluated in postmortem pancreata. RESULTS The standard STDS detected only 45% of the pancrea…
Use of flow cytometry and confocal microscopy techniques to investigate early CdCl(2)-induced nephrotoxicity in vitro.
2001
CdCl(2) is a well-known toxic compound for the kidney in vivo and in vitro. We report here part of the results of an ECVAM (European Centre for the Validation of Alternative Methods) contract study, aimed at establishing and assessing several flow cytometric and confocal microscopic endpoints for use in an in vitro nephrotoxicity model. Three renal tubule cell lines, OK (opossum, proximal tubule origin), LLC-PK1 (pig, proximal tubule origin) and MDCK (dog, distal tubule origin) were exposed for 1, 5 and 24 h to 25 microM and 100 microM CdCl(2). The results obtained for mitochondrial membrane potential showed a decrease in all the cell lines after 5 h of treatment with both CdCl(2) concentra…
Margination of Fluorescent Polylactic Acid-Polyaspartamide based Nanoparticles in Microcapillaries In Vitro: the Effect of Hematocrit and Pressure.
2017
The last decade has seen the emergence of vascular-targeted drug delivery systems as a promising approach for the treatment of many diseases, such as cardiovascular diseases and cancer. In this field, one of the major challenges is carrier margination propensity (i.e., particle migration from blood flow to vessel walls); indeed, binding of these particles to targeted cells and tissues is only possible if there is direct carrier–wall interaction. Here, a microfluidic system mimicking the hydrodynamic conditions of human microcirculation in vitro is used to investigate the effect of red blood cells (RBCs) on a carrier margination in relation to RBC concentration (hematocrit) and pressure drop…
Unusual triskelion patterns and dye-labelled GUVs: consequences of the interaction of cholesterol-containing linear-hyperbranched block copolymers wi…
2015
Cholesterol (Ch) linked to a linear-hyperbranched block copolymer composed of poly(ethylene glycol) (PEG) and poly(glycerol) (hbPG) was investigated for its membrane anchoring properties. Two polyether-based linear-hyperbranched block copolymers with and without a covalently attached rhodamine fluorescence label (Rho) were employed (Ch-PEG30-b-hbPG23 and Ch-PEG30-b-hbPG17-Rho). Compression isotherms of co-spread 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) or 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) with the respective polymers were measured on the Langmuir trough and the morphology development of the liquid-condensed (LC) domains was studied by epi-fluorescence microsc…
Toward oxygen binding curves of single respiratory proteins
2004
Oxygen binding curves of single molecules promise to discriminate between different models describing cooperativity because load distributions are accessible. Individual tarantula hemocyanins could be detected by fluorescence correlation spectroscopy using intrinsic tryptophan fluorescence as sensor of bound oxygen. However, imaging of immobilized proteins was not possible due to fast photo-bleaching. It is shown that tetra-methyl-carboxy-rhodamine (TAMRA), commonly used as a fluorescence label in single-molecule spectroscopy, can also be applied to monitor bound oxygen. The dye's fluorescence is quenched due to Förster energy transfer to the oxygenated active sites of hemocyanin.
Tuning the surface of nanoparticles: Impact of poly(2-ethyl-2-oxazoline) on protein adsorption in serum and cellular uptake
2016
Item does not contain fulltext Due to the adsorption of biomolecules, the control of the biodistribution of nanoparticles is still one of the major challenges of nanomedicine. Poly(2-ethyl-2-oxazoline) (PEtOx) for surface modification of nanoparticles is applied and both protein adsorption and cellular uptake of PEtOxylated nanoparticles versus nanoparticles coated with poly(ethylene glycol) (PEG) and non-coated positively and negatively charged nanoparticles are compared. Therefore, fluorescent poly(organosiloxane) nanoparticles of 15 nm radius are synthesized, which are used as a scaffold for surface modification in a grafting onto approach. With multi-angle dynamic light scattering, asym…