The Experts below are selected from a list of 570492 Experts worldwide ranked by ideXlab platform
Yael Kopelman - One of the best experts on this subject based on the ideXlab platform.
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melanosis coli a helpful Contrast Effect or a harmful pigmentation
Clinical Medicine Insights: Gastroenterology, 2018Co-Authors: Fadi Abu Baker, Amir Mari, Dan Feldman, Muhammad Suki, Oren Gal, Yael KopelmanAbstract:Background:Melanosis coli, a brown discoloration of colonic mucosa, is considered as a benign condition mainly observed in patients under chronic anthranoid laxatives. Recent data link this conditi...
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Melanosis Coli: A Helpful Contrast Effect or a Harmful Pigmentation?
SAGE Publishing, 2018Co-Authors: Fadi Abu Baker, Amir Mari, Dan Feldman, Muhammad Suki, Oren Gal, Yael KopelmanAbstract:Background: Melanosis coli, a brown discoloration of colonic mucosa, is considered as a benign condition mainly observed in patients under chronic anthranoid laxatives. Recent data link this condition with an increased adenoma detection rate. Moreover, its tumorigenic potential and possible association with the development of colorectal cancer remains uncertain. We conducted this study to compare the polyp detection rate and colorectal cancer diagnosis in patients with melanosis against matched control group without melanosis. Patients and methods: A retrospective single-center study. Patients diagnosed with melanosis coli on colonoscopy over a 15-year period were included. Each melanosis coli patient was matched with three controls by age, gender, setting (inpatient/outpatient), and procedure’s indication. Polyp detection rate and diagnosis of colorectal cancer were recorded and compared between the groups before and after adjustment for bowel preparation. Results: A cohort of 718 patients with melanosis and 2154 controls were included. The polyp detection rates were 33.4% and 21.8% of melanosis and control groups, respectively ( P
Taeghwan Hyeon - One of the best experts on this subject based on the ideXlab platform.
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continuous o2 evolving mnfe2o4 nanoparticle anchored mesoporous silica nanoparticles for efficient photodynamic therapy in hypoxic cancer
Journal of the American Chemical Society, 2017Co-Authors: Jonghoon Kim, Hye Rim Cho, Dokyoon Kim, Changyeong Song, Nohyun Lee, Hyejin Jeon, Seung Hong Choi, Taeghwan HyeonAbstract:Therapeutic Effects of photodynamic therapy (PDT) are limited by cancer hypoxia because the PDT process is dependent on O2 concentration. Herein, we design biocompatible manganese ferrite nanoparticle-anchored mesoporous silica nanoparticles (MFMSNs) to overcome hypoxia, consequently enhancing the therapeutic efficiency of PDT. By exploiting the continuous O2-evolving property of MnFe2O4 nanoparticles through the Fenton reaction, MFMSNs relieve hypoxic condition using a small amount of nanoparticles and improve therapeutic outcomes of PDT for tumors in vivo. In addition, MFMSNs exhibit T2 Contrast Effect in magnetic resonance imaging (MRI), allowing in vivo tracking of MFMSNs. These findings demonstrate great potential of MFMSNs for theranostic agents in cancer therapy.
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paramagnetic inorganic nanoparticles as t1 mri Contrast agents
Wiley Interdisciplinary Reviews-nanomedicine and Nanobiotechnology, 2014Co-Authors: Hyon Bin Na, Taeghwan HyeonAbstract:Magnetic resonance imaging (MRI) is one of the most powerful molecular imaging techniques and can noninvasively visualize and quantify biological processes within the living organisms. The introduction of exogenous Contrast agents has allowed specific visualization of biological targets as well as enhanced the sensitivity of MRI. Recently, paramagnetic inorganic nanoparticles showing positive T1 Contrast Effect have been investigated as T1 MRI Contrast agents. Since the first trials of spherical nanoparticles of manganese oxide and gadolinium oxide, inorganic nanoparticles of various compositions and shapes have been used for in vivo and in vitro MRI because of their distinct signal enhancement in MR images. However, for clinical applications, important and complex issues such as safety and efficiency should be investigated by active research encompassing multiple disciplines, including chemistry, biology, biomedical engineering, and medicine. For further resources related to this article, please visit the WIREs website. Conflict of interest: The authors have declared no conflicts of interest for this article.
Florence Gazeau - One of the best experts on this subject based on the ideXlab platform.
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biodegradation mechanisms of iron oxide monocrystalline nanoflowers and tunable shield Effect of gold coating
Small, 2014Co-Authors: Yasir Javed, Lenaic Lartigue, Pierre Hugounenq, Quoc Lam Vuong, Yves Gossuin, Christian Ricolleau, Rana Bazzi, Claire Wilhelm, Florence GazeauAbstract:U nderstanding the relation between the structure and the reactivity of nanomaterials in the organism is a crucial step towards effi cient and safe biomedical applications. The multi-scale approach reported here, allows following the magnetic and structural transformations of multicore maghemite nanofl owers in a medium mimicking intracellular lysosomal environment. By confronting atomic-scale and macroscopic information on the biodegradation of these complex nanostuctures, we can unravel the mechanisms involved in the critical alterations of their hyperthermic power and their Magnetic Resonance imaging T 1 and T 2 Contrast Effect. This transformation of multicore nanoparticles with outstanding magnetic properties into poorly magnetic single core clusters highlights the harmful infl uence of cellular medium on the therapeutic and diagnosis Effectiveness of iron oxide-based nanomaterials. As biodegradation occurs through surface reactivity mechanism, we demonstrate that the inert activity of gold nanoshells can be exploited to protect iron oxide nanostructures. Such inorganic nanoshields could be a relevant strategy to modulate the degradability and ultimately the long term fate of nanomaterials in the organism.
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cooperative organization in iron oxide multi core nanoparticles potentiates their efficiency as heating mediators and mri Contrast agents
ACS Nano, 2012Co-Authors: Lenaic Lartigue, Pierre Hugounenq, Rana Bazzi, Claire Wilhelm, Damien Alloyeau, Sarah P Clarke, Michael Levy, J C Bacri, Dermot F Brougham, Florence GazeauAbstract:In the pursuit of optimized magnetic nanostructures for diagnostic and therapeutic applications, the role of nanoparticle architecture has been poorly investigated. In this study, we demonstrate that the internal collective organization of multi-core iron oxide nanoparticles can modulate their magnetic properties in such a way as to critically enhance their hyperthermic efficiency and their MRI T1 and T2 Contrast Effect. Multi-core nanoparticles composed of maghemite cores were synthesized through a polyol approach, and subsequent electrostatic colloidal sorting was used to fractionate the suspensions by size and hence magnetic properties. We obtained stable suspensions of citrate-stabilized nanostructures ranging from single-core 10 nm nanoparticles to multi-core magnetically cooperative 30 nm nanoparticles. Three-dimensional oriented attachment of primary cores results in enhanced magnetic susceptibility and decreased surface disorder compared to individual cores, while preserving a superparamagnetic-li...
Yong Sheng Zhao - One of the best experts on this subject based on the ideXlab platform.
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inorganic nanoparticle based t1 and t1 t2 magnetic resonance Contrast probes
Nanoscale, 2012Co-Authors: Fengqin Hu, Yong Sheng ZhaoAbstract:Magnetic resonance imaging (MRI) yields high spatially resolved Contrast with anatomical details for diagnosis, deeper penetration depth and rapid 3D scanning. To improve imaging sensitivity, adding Contrast agents accelerates the relaxation rate of water molecules, thereby greatly increasing the Contrast between specific issues or organs of interest. Currently, the majority of T1 Contrast agents are paramagnetic molecular complexes, typically Gd(III) chelates. Various nanoparticulate T1 and T1/T2 Contrast agents have recently been investigated as novel agents possessing the advantages of both the T1 Contrast Effect and nanostructural characteristics. In this minireview, we describe the recent progress of these inorganic nanoparticle-based MRI Contrast agents. Specifically, we mainly report on Gd and Mn-based inorganic nanoparticles and ultrasmall iron oxide/ferrite nanoparticles.
Chia Hao Su - One of the best experts on this subject based on the ideXlab platform.
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nanoshell magnetic resonance imaging Contrast agents
Journal of the American Chemical Society, 2007Co-Authors: Chia Hao Su, Hwoshuenn Sheu, Chihchia Huang, Yi Wei Lo, Yingchih Pu, Juncheng Weng, Darbin Shieh, Jyhhorng ChenAbstract:NanoContrast agents have great potential in magnetic resonance (MR) molecular imaging applications for clinical diagnosis. We synthesized Au 3 Cu 1 (gold and copper) nanoshells that showed a promising MR Contrast Effect. For in vitro MR images, the large proton r 1 relaxivities brightened T 1 -weighted images. As for the proton-dephasing Effect in T 2 , Au 3 Cu 1 lightened MR images at the low concentration of 0.125 mg mL -1 (3.84 x 10 -7 mM), and then the signal continuously decreased as the concentration increased. For in vivo MR imaging, Au 3 Cu 1 nanoContrast agents enhanced the Contrast of blood vessels and suggested their potential use in MR angiography as blood-pool agents. We propose that (1) the cooperativity originating from the form of the nanoparticles and (2) the large surface area coordinated to water from their porous hollow morphology are important for efficient relaxivity. In a cytotoxicity and animal survival assay, Au 3 Cu 1 nanoContrast agents showed a dose-dependent toxic Effect: the viability rate of experimental mice reached 83% at a dose of 20 mg kg -1 and as much as 100% at 2 mg kg -1 .
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aqueous dispersions of magnetite nanoparticles with nh3 surfaces for magnetic manipulations of biomolecules and mri Contrast agents
Biomaterials, 2005Co-Authors: Darbin Shieh, Chia Hao Su, Fong Yu Cheng, Ming Ting Wu, Ya Na Wu, Chiau Yuang Tsai, Chaoliang Wu, Donghwang Chen, Chenhsi ChouAbstract:Abstract In the current study, amine surface modified iron-oxide nanoparticles of 6 nm diameter without polymer coating were fabricated in an aqueous solution by organic acid modification as an adherent following chemical coprecipitation. Structure and the superparamagnetic property of magnetite nanoparticles were characterized by selected area electron diffraction (SAED) and superconducting quantum interference measurement device (SQUID). X-ray photoelectron spectrometer (XPS) and zeta potential measurements revealed cationic surface mostly decorated with terminal –NH 3 + . This feature enables them to function as a magnetic carrier for nucleotides via electrostatic interaction. In addition, Fe 3 O 4 /trypsin conjugates with well-preserved functional activity was demonstrated. The nanoparticles displayed excellent in vitro biocompatibility. The NMR and the in vitro MRI measurements showed significantly reduced water proton relaxation times of both T 1 and T 2 . Significantly reduced T 2 and T 2 *-weighted signal intensity were observed in a 1.5 T clinical MR imager. In vivo imaging Contrast Effect showed a fast and prolonged inverse Contrast Effect in the liver that lasted for more than 1 week. In addition, it was found that the spherical Fe 3 O 4 assembled as rod-like configuration through an aging process in aqueous solution at room temperature. Interestingly, TEM observation of the liver tissue revealed the rod-like shape but not the spherical-type nanoparticles being taken up by the Kupffer cells 120 h after tail vein infusion. Combining these results, we have demonstrated the potential applications of the newly synthesized magnetite nanoparticles in a broad spectrum of biomedical applications.
