Search

Near-infrared (NIR) water-dispersible fluorescent tags are of big importance for biomedical imaging. Bright, stable, biocompatible NIR fluorescent nanoparticles have great translation potential to improve diagnosis of early stages of different diseases. Here we report on the synthesis of exceptionally bright ("ultrabright") fluorescent meso(nano)porous silica nanoparticles of 28 ± 3 nm in diameter. The NIR fluorescent dye LS277 is encapsulated inside these silica nanoparticles. The wavelengths of the maximum excitation/ fluorescence of the particles are 804/815 nm. The absorptivity coefficient of the particles is 2.1 x 10[sup 8] M[sup -1] cmT[sub 1] at 805 nm and the quantum yield of the dye increased by a factor of 5 after encapsulating to 1.5%. The fluorescent brightness of these particles is more than 2000x higher than the fluorescence of one molecule of LS277 in water. When exited in NIR spectral region (>700 nm), these particles are up to 4x brighter than QD800 commercial quantum dots emitting at 800 nm. We demonstrate that the synthesized NIR mesoporous silica nanoparticles easily internalize 4T[sub 1]luc breast tumor cells, and remain bright for more than 9 weeks whereas the dye is completely bleached by that time. [ABSTRACT FROM AUTHOR]

Near-infrared (NIR) water-dispersible fluorescent tags are of big importance for biomedical imaging. Bright, stable, biocompatible NIR fluorescent nanoparticles have great translation potential to improve diagnosis of early stages of different diseases. Here we report on the synthesis of exceptionally bright ("ultrabright") fluorescent meso(nano)porous silica nanoparticles of 28 ± 3 nm in diameter. The NIR fluorescent dye LS277 is encapsulated inside these silica nanoparticles. The wavelengths of the maximum excitation/ fluorescence of the particles are 804/815 nm. The absorptivity coefficient of the particles is 2.1 x 10[sup 8] M[sup -1] cm[sup -1] at 805 nm and the quantum yield of the dye increased by a factor of 5 after encapsulating to 1.5%. The fluorescent brightness of these particles is more than 2000x higher than the fluorescence of one molecule of LS277 in water. When exited in NIR spectral region (>700 nm), these particles are up to 4x brighter than QD800 commercial quantum dots emitting at 800 nm. We demonstrate that the synthesized NIR mesoporous silica nanoparticles easily internalize 4Tlluc breast tumor cells, and remain bright for more than 9 weeks whereas the dye is completely bleached by that time. [ABSTRACT FROM AUTHOR]

Objective:To determine whether obesity-induced hypertension was associated with alterations in vascular contractility and/or cardiac function.Design:Male Sprague–Dawley rats were fed either a low fat (LF; 11% kcal as fat) or a moderately high fat (MHF; 32% kcal as fat) diet for 11 weeks.Measurements:Body weight; mean arterial pressure; angiotensin peptides; mesenteric contractile response to phenylephrine (PE), potassium chloride (KCl), serotonin, angiotensin II (AngII), calcium chloride; baseline and isoproterenol-induced cardiac contractility; baseline and isoproterenol-induced coronary artery blood flow.Results:Rats fed the MHF diet segregated into obesity-prone (OP) and obesity-resistant (OR) groups. OP rats exhibited elevations in mean arterial pressure (MAP) and elevations in systemic concentrations of angiotensin peptides. Mesenteric arteries from OP rats exhibited a greater contractile response to PE, KCl and serotonin (5-HT). Heightened responses to PE persisted in arteries from OP rats even after normalization of the response to KCl. In contrast, the response of permeabilized mesenteric arteries to a maximal concentration of calcium was similar in rats from each group. Isolated perfused hearts exhibited similar baseline and isoproterenol-induced contractility in rats from each group. However, isoproterenol was unable to increase coronary artery blood flow in hearts from OP rats.Conclusion:Enhanced vascular reactivity may contribute to obesity-induced hypertension, while reductions in coronary artery relaxation would impair the ability of the heart to respond to increased myocardial demand.International Journal of Obesity (2007) 31, 1652–1659; doi:10.1038/sj.ijo.0803426; published online 4 July 2006 [ABSTRACT FROM AUTHOR]

Summary. The purpose of this study was to establish the rat left ventricle (LV) tissue slice system for examination of norepinephrine (NE) release from sympathetic nerve terminals. Moreover, initial experiments were performed to use the LV tissue slice system to examine differences in NE uptake and release following cardiac pressure overload induced by abdominal aortic constriction (AC). Kinetic parameters (Vmax, Km) for the specific uptake of [3H]-NE demonstrated high affinity (Km, 1.94 ± 0.83 μM) and moderate capacity uptake (Vmax, 182 ± 6 fmol/mg/weight/min). Following 10 days of pressure overload, the Vmax for [3H]-NE uptake was significantly reduced (by 46%) in LV slices from AC rats compared to sham-operated (SO) controls. In control rat LV slices preloaded with [3H]-NE, electrically evoked [3H]-overflow was calcium- and stimulus pulse number-dependent. The neuronal uptake inhibitor, desipramine (DMI), increased (by 60%) evoked [3H]-overflow from LV slices. The α2-agonist, UK14304, decreased evoked [3H]-overflow from LV slices in a concentration-dependent manner (maximal reduction of 75%). The β2-agonist, salbutamol, increased evoked [3H]-overflow from LV slices in a concentration-dependent manner (maximal increase of 200%). In separate experiments, the LV tissue slice system was used to examine the effect of pressure overload on evoked [3H]-overflow. Following 10 days of pressure overload, evoked [3H]-overflow from LV slices of AC rats was increased (by 50%) compared to SO control. Increases in evoked [3H]-overflow from LV slices of AC rats compared to SO controls remained evident in the presence of DMI. These results demonstrate the relative importance of NE release and uptake using an in vitro LV tissue slice system. Sympathetic nerve terminals innervating rat LV were demonstrated to possess functional presynaptic α2- and β2-adrenergic receptors. Finally, using this LV tissue slice system, reductions in the uptake velocity and increases in evoked NE release were demonstrated in response to acute cardiac pressure overload. [ABSTRACT FROM AUTHOR]

The water content of human stratum corneum has been measured gravimetrically in vitro in relation to relative humidity (RH) and temperature. Water content increased with increasing RH. Stratum corneum water content increased 50% when the temperature was raised from 20 to 35°C at RH below 60%. Temperature dependence decreased with increasing RH until there was essentially no temperature dependence at 90% RH. The conclusion is that temperature changes could significantly affect water content in viva and pliability of skin at RH below 60%. [ABSTRACT FROM AUTHOR]

A correction to the article "Interaction of Fluorescent Molecular Rotors With Blood Plasma Proteins ,"W. J. Akers, J. M. Cupps and M. A. Haidekker is presented.