1,167 research outputs found
Cardiac protective effects of Moringa oleifera seeds in spontaneous hypertensive rats
BACKGROUND Hypertension is characterized by a maintained high blood pressure leading to cardiac complications such as left ventricular hypertrophy and fibrosis and an increased risk of heart failure and myocardial infarction. This study investigated the cardiac effects of oral administration of Moringa oleifera (MOI) seed powder in spontaneous hypertensive rats (SHR).
METHODS SHR received food containing MOI seed powder (750mg/d, 8 weeks) or normal food. In vivo measurement of hemodynamic parameters by telemetry and cardiac structure and function analysis by echocardiography were performed. Histological studies were performed to determine fibrosis and protein expression.
RESULTS MOI treatment did not modify blood pressure in SHR but reduced nocturnal heart rate and improved cardiac diastolic function (reduction of isovolumetric relaxation time and deceleration time of the E wave, increase of ejection volume and cardiac output compared to nontreated SHR). Left ventricular anterior wall thickness, interseptal thickness on diastole, and relative wall thickness were reduced after MOI treatment. Furthermore, we found a significant reduction of fibrosis in the left ventricle of MOI-treated SHR. This antihypertrophic and antifibrotic effect of MOI was associated with increased expression of peroxisome proliferator-activated receptor (PPAR)-α and δ, reduced cardiac triglyceride level, and enhanced plasmatic prostacyclins.
CONCLUSIONS Our data show a beneficial effect of MOI on the cardiac structure and function in SHR associated with an upregulation of PPAR-α and δ signaling. This study thus provides scientific rational support for the empirical use of MOI in the traditional Malagasy medicine against cardiac diseases associated with blood pressure overload
Self-Dual Bending Theory for Vesicles
We present a self-dual bending theory that may enable a better understanding
of highly nonlinear global behavior observed in biological vesicles. Adopting
this topological approach for spherical vesicles of revolution allows us to
describe them as frustrated sine-Gordon kinks. Finally, to illustrate an
application of our results, we consider a spherical vesicle globally distorted
by two polar latex beads.Comment: 10 pages, 3 figures, LaTeX2e+IOPar
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High-throughput smFRET analysis of freely diffusing nucleic acid molecules and associated proteins
Single-molecule Förster resonance energy transfer (smFRET) is a powerful technique for nanometer-scale studies of single molecules. Solution-based smFRET, in particular, can be used to study equilibrium intra- and intermolecular conformations, binding/unbinding events and conformational changes under biologically relevant conditions without ensemble averaging. However, single-spot smFRET measurements in solution are slow. Here, we detail a high-throughput smFRET approach that extends the traditional single-spot confocal geometry to a multispot one. The excitation spots are optically conjugated to two custom silicon single photon avalanche diode (SPAD) arrays. Two-color excitation is implemented using a periodic acceptor excitation (PAX), allowing distinguishing between singly- and doubly-labeled molecules. We demonstrate the ability of this setup to rapidly and accurately determine FRET efficiencies and population stoichiometries by pooling the data collected independently from the multiple spots. We also show how the high throughput of this approach can be used o increase the temporal resolution of single-molecule FRET population characterization from minutes to seconds. Combined with microfluidics, this high-throughput approach will enable simple real-time kinetic studies as well as powerful molecular screening applications
Etude de l’extrait hexanique de l’espèce Ferula vesceritensis par les techniques couplées LC-UV-DAD, LC-MS et GC-MS
Phase ordering and shape deformation of two-phase membranes
Within a coupled-field Ginzburg-Landau model we study analytically phase
separation and accompanying shape deformation on a two-phase elastic membrane
in simple geometries such as cylinders, spheres and tori. Using an exact
periodic domain wall solution we solve for the shape and phase ordering field,
and estimate the degree of deformation of the membrane. The results are
pertinent to a preferential phase separation in regions of differing curvature
on a variety of vesicles.Comment: 4 pages, submitted to PR
Decreased MCM2-6 in Drosophila S2 cells does not generate significant DNA damage or cause a marked increase in sensitivity to replication interference.
A reduction in the level of some MCM proteins in human cancer cells (MCM5 in U20S cells or MCM3 in Hela cells) causes a rapid increase in the level of DNA damage under normal conditions of cell proliferation and a loss of viability when the cells are subjected to replication interference. Here we show that Drosophila S2 cells do not appear to show the same degree of sensitivity to MCM2-6 reduction. Under normal cell growth conditions a reduction of >95% in the levels of MCM3, 5, and 6 causes no significant short term alteration in the parameters of DNA replication or increase in DNA damage. MCM depleted cells challenged with HU do show a decrease in the density of replication forks compared to cells with normal levels of MCM proteins, but this produces no consistent change in the levels of DNA damage observed. In contrast a comparable reduction of MCM7 levels has marked effects on viability, replication parameters and DNA damage in the absence of HU treatment
Sesquiterpenes from aerial parts of Ferula vesceritensis
From the dichloromethane extract of aerial parts of Ferula vesceritensis (Apiaceae), 11 sesquiterpene derivatives were isolated. Among them five were compounds designated as 10-hydroxylancerodiol-6-anisate, 2,10-diacetyl-8-hydroxyferutriol-6-anisate, 10-hydroxylancerodiol-6-benzoate, vesceritenone and epoxy-vesceritenol. The six known compounds were identified as feselol, farnesiferol A, lapidol, 2-acetyl-jaeschkeanadiol-6-anisate, lasidiol-10-anisate and 10-oxo-jaesckeanadiol-6-anisate. All the structures were determined by extensive spectroscopic studies including 1D and 2D NMR experiments and mass spectroscopy analysis. Two of the compounds, the sesquiterpene coumarins farnesiferol A and feselol, bound to the model recombinant nucleotide-binding site of an MDR-like efflux pump from the enteropathogenic protozoan Cryptosporidium parvum
Photoluminescent diamond nanoparticles for cell labeling: study of the uptake mechanism in mammalian cells
Diamond nanoparticles (nanodiamonds) have been recently proposed as new
labels for cellular imaging. For small nanodiamonds (size <40 nm) resonant
laser scattering and Raman scattering cross-sections are too small to allow
single nanoparticle observation. Nanodiamonds can however be rendered
photoluminescent with a perfect photostability at room temperature. Such a
remarkable property allows easier single-particle tracking over long
time-scales. In this work we use photoluminescent nanodiamonds of size <50 nm
for intracellular labeling and investigate the mechanism of their uptake by
living cells . By blocking selectively different uptake processes we show that
nanodiamonds enter cells mainly by endocytosis and converging data indicate
that it is clathrin mediated. We also examine nanodiamonds intracellular
localization in endocytic vesicles using immunofluorescence and transmission
electron microscopy. We find a high degree of colocalization between vesicles
and the biggest nanoparticles or aggregates, while the smallest particles
appear free in the cytosol. Our results pave the way for the use of
photoluminescent nanodiamonds in targeted intracellular labeling or biomolecule
deliver
Deep-Tissue Anatomical Imaging of Mice Using Carbon Nanotube Fluorophores in the Second Near Infrared Window
Fluorescent imaging in the second near infrared window (NIR II, 1-1.4 {\mu}m)
holds much promise due to minimal autofluorescence and tissue scattering. Here,
using well functionalized biocompatible single-walled carbon nanotubes (SWNTs)
as NIR II fluorescent imaging agents, we performed high frame rate video
imaging of mice during intravenous injection of SWNTs and investigated the path
of SWNTs through the mouse anatomy. We observed in real-time SWNT circulation
through the lungs and kidneys several seconds post-injection, and spleen and
liver at slightly later time points. Dynamic contrast enhanced imaging through
principal component analysis (PCA) was performed and found to greatly increase
the anatomical resolution of organs as a function of time post-injection.
Importantly, PCA was able to discriminate organs such as the pancreas which
could not be resolved from real-time raw images. Tissue phantom studies were
performed to compare imaging in the NIR II region to the traditional NIR I
biological transparency window (700- 900 nm). Examination of the feature sizes
of a common NIR I dye (indocyanine green, ICG) showed a more rapid loss of
feature contrast and integrity with increasing feature depth as compared to
SWNTs in the NIR II region. The effects of increased scattering in the NIR I
versus NIR II region were confirmed by Monte Carlo simulation. In vivo
fluorescence imaging in the NIR II region combined with PCA analysis may
represent a powerful approach to high resolution optical imaging through deep
tissues, useful for a wide range of applications from biomedical research to
disease diagnostics.Comment: Proceedings of the National Academy of Sciences (PNAS), 201
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