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1.
J Neurosci Methods ; 344: 108838, 2020 10 01.
Article in English | MEDLINE | ID: mdl-32619586

ABSTRACT

BACKGROUND: The study aimed to establish a staining method that could delineate the macroscopic lesion boundary of a hyperacute infarction depicted by diffusion-weighted MRI (DWI) and to validate the infarction boundary by comparing different staining methods. NEW METHOD: Thirteen rats with 1 -h middle cerebral artery (MCA) infarction were included. Five different staining methods (Hematoxylin and eosin (H&E), Nissl, 2,3,5-triphenyltetrazolium hydrochloride (TTC), microtubule associated protein 2 (MAP2), and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) stains) were used to identify whether the hyperacute infarction could be histopathologically identified. Dice indices were compared to evaluate similarities in the lesion area ascertained by DWI and the staining methods. Through macroscopic lesion delineation, each region was subdivided into abnormal regions in all three stains (ROIA), abnormal in two stains (ROIB), and abnormal in only one (ROIC). Microscopic cellular changes were evaluated and graded according to each region. RESULTS: Mean Dice indices of the H&E stain were significantly higher than those of the Nissl- and MAP2-stained specimens (0.83 ±â€¯0.052, 0.58 ±â€¯0.107, and 0.56 ±â€¯0.059, respectively; p = 0.000). Grading scores for ROIs in the DWI abnormal lesions varied by region: ROIA exhibited the most severe damage [median (IQR), 3 (1)], followed respectively by ROIB [median (IQR), 2 (0)] and ROIC [median (IQR), 1 (0)] COMPARISON WITH EXISTING METHODS: H&E stain best reflects 1 h hyperacute DWI abnormal lesions. CONCLUSIONS: H&E stain allowed for the macroscopic delineation of the 1 h DWI-abnormal lesions, while MAP2 and Nissl stains could only partially depict lesions.


Subject(s)
Diffusion Magnetic Resonance Imaging , Infarction, Middle Cerebral Artery , Animals , Infarction, Middle Cerebral Artery/diagnostic imaging , Rats , Staining and Labeling
2.
ACS Biomater Sci Eng ; 6(8): 4390-4396, 2020 08 10.
Article in English | MEDLINE | ID: mdl-33455188

ABSTRACT

A hybrid composite of silver nanoparticles (AgNPs) and porous silicon microparticles (pSiMPs) was developed and applied for the computed tomography (CT) scanning of the lungs as an image-guided localization agent. We confirmed the grafting of AgNPs on oxidized pSiMPs template using various analytical equipment, including a scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDS). The hybrid composite showed a high CT contrast intensity (>1000 HU) that enabled us to produce and view images of the lungs. In addition, it showed the ability to maintain a strong CT signal at the injected area of the rabbit's lungs, up to an hour, without spreading. The lack of toxicity and immune response indicated that the composite could be fully utilized as a new image-guided localization agent of CT scans for lung cancer surgery.


Subject(s)
Metal Nanoparticles , Silver , Animals , Lung/diagnostic imaging , Porosity , Rabbits , Silicon , Tomography , Tomography, X-Ray Computed
3.
Biomed Res Int ; 2015: 565391, 2015.
Article in English | MEDLINE | ID: mdl-26413534

ABSTRACT

Magnetization transfer ratio (MTR) has been often used for imaging myelination. Despite its high sensitivity, the specificity of MTR to myelination is not high because tissues with no myelin such as muscle can also show high MTR. In this study, we propose a new magnetization transfer (MT) indicator, MT asymmetry (MTA), as a new method of myelin imaging. The experiments were performed on rat brain at 9.4 T. MTA revealed high signals in white matter and significantly low signals in gray matter and muscle, indicating that MTA has higher specificity than MTR. Demyelination and remyelination studies demonstrated that the sensitivity of MTA to myelination was as high as that of MTR. These experimental results indicate that MTA can be a good biomarker for imaging myelination. In addition, MTA images can be efficiently acquired with an interslice MTA method, which may accelerate clinical application of myelin imaging.


Subject(s)
Brain/pathology , Demyelinating Diseases/pathology , Image Processing, Computer-Assisted/methods , Magnetic Resonance Imaging/methods , Myelin Sheath/pathology , Animals , Brain/anatomy & histology , Magnets , Male , Rats , Rats, Sprague-Dawley
4.
Biomaterials ; 34(33): 8114-21, 2013 Nov.
Article in English | MEDLINE | ID: mdl-23932293

ABSTRACT

Research into multifunctional nanoparticles is focused on creating an agent for use in an all-in-one multimodal imaging system that includes diagnostic imaging, drug delivery, and therapeutic monitoring. We designed a new dual-modality tumor-targeting agent with a new tumor-targeting molecule, oleanolic acid (OA), which is derived from a natural compound and coupled with a macrocyclic chelating agent such as 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA), iron oxide nanoparticles (IONP), and radiolabeling components such as (68)Ga for dual-modality positron emission tomography (PET)/magnetic resonance imaging (MRI). We attempted to obtain fusion PET/MR images with the (68)Ga-NOTA-OA-IONP hybrid tumor-targeting imaging agent using colon cancer (HT-29) xenograft mice models. The HT-29 cancer cells showed high uptake of (68)Ga-NOTA-OA-IONP, which also had an inhibitory effect on the cells. Moreover, we obtained PET and MRI tumor images as well as fusion PET/MRI images of the tumors using (68)Ga-NOTA-OA-IONP. Therefore, the dual-modality cancer-targeting radiolabeled nanoparticle reported here is a potent imaging agent that is suitable for PET, MRI, and PET/MRI-based diagnosis of tumors; it also has the advantage of not only detecting tumor functionality, but also simultaneously aiding in tumor resolution.


Subject(s)
Ferric Compounds/chemistry , Magnetic Resonance Imaging/methods , Nanoparticles/chemistry , Oleanolic Acid/chemistry , Positron-Emission Tomography/methods , Animals , Cell Proliferation/drug effects , Colonic Neoplasms/diagnosis , HT29 Cells , Humans , Male , Mice , Mice, Nude , Nanoparticles/therapeutic use
5.
Magn Reson Med ; 70(3): 620-9, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23023916

ABSTRACT

The applicability of the in vivo proton magnetic resonance spectroscopy hepatic lipid profiling (MR-HLP) technique in nonalcoholic fatty liver disease was investigated. Using magnetic resonance spectroscopy, the relative fractions of diunsaturated (fdi), monounsaturated (fmono), and saturated (fsat) fatty acids as well as total hepatic lipid content were estimated in the livers of 8 control and 23 CCl4-treated rats at 9.4 T. The mean steatosis, necrosis, inflammation, and fibrosis scores of the treated group were all significantly higher than those of the control group (P < 0.01). There was a strong correlation between the histopathologic parameters and the MR-HLP parameters (r = 0.775, P < 0.01) where both steatosis and fibrosis are positively correlated with fmono and negatively correlated with fdi. Both necrosis and inflammation, however, were not correlated with any of the MR-HLP parameters. Hepatic lipid composition appears to be changed in association with the severity of steatosis and fibrosis in nonalcoholic fatty liver disease, and these changes can be depicted in vivo by using the MR-HLP method at 9.4 T. Thus, while it may not likely be that MR-HLP helps differentiate between steatohepatitis in its early stages and simple steatosis, these findings altogether are in support of potential applicability of in vivo MR-HLP at high field in nonalcoholic fatty liver disease.


Subject(s)
Lipids/analysis , Liver/chemistry , Magnetic Resonance Spectroscopy , Non-alcoholic Fatty Liver Disease/diagnosis , Animals , Fatty Acids/analysis , Fatty Acids, Monounsaturated/analysis , Fatty Liver/diagnosis , Fibrosis , Liver/pathology , Male , Necrosis , Non-alcoholic Fatty Liver Disease/pathology , Rats , Rats, Sprague-Dawley
6.
Biomaterials ; 33(24): 5865-74, 2012 Aug.
Article in English | MEDLINE | ID: mdl-22617320

ABSTRACT

We present a facile synthesis of europium-doped gadolinium sulfide (GdS:Eu(3+)) opto-magnetic nanoparticles (NPs) via sonochemistry. Their photoluminescence and strong paramagnetic properties enable these NPs to be utilized as an in vitro cell imaging and in vivo T(1)-weighted MR imaging probe. The GdS:Eu(3+) NPs have a prominent longitudinal (r(1)) relaxivity value, which is a critical parameter for T(1)-weighted MR imaging. Here, we showed not only their strong positive contrast effect to blood vessels and organs of mice, but also blood half-life and biodistribution including clearance from organs, in order to assess the GdS:Eu(3+) NPs as a competent nanocrystal-based T(1) contrast agent. We further showed confocal images of breast cancer cells containing GdS:Eu(3+) NPs to evaluate as a photoluminescence probe. Dual-mode imaging capability obtained from the GdS:Eu(3+) NPs will allow target-oriented cellular imaging as well as the resulting disease-specific MR imaging.


Subject(s)
Breast Neoplasms/diagnosis , Contrast Media , Europium , Gadolinium , Luminescent Measurements/methods , Magnetic Resonance Imaging/methods , Nanoparticles , Animals , Breast/pathology , Breast Neoplasms/pathology , Cell Line, Tumor , Contrast Media/chemistry , Contrast Media/pharmacokinetics , Europium/chemistry , Europium/pharmacokinetics , Female , Gadolinium/chemistry , Gadolinium/pharmacokinetics , Half-Life , Humans , Mice , Mice, Inbred BALB C , Microscopy, Confocal/methods , Nanoparticles/chemistry , Sulfides/chemistry , Sulfides/pharmacokinetics
7.
J Magn Reson ; 217: 86-91, 2012 Apr.
Article in English | MEDLINE | ID: mdl-22436467

ABSTRACT

To evaluate the efficiency and feasibility of intermolecular multiple quantum coherence (iMQC) magnetic resonance (MR) imaging for single cell detection, we obtained intermolecular double quantum coherence (iDQC) and conventional gradient echo (GE) images of macrophage cells labeled by contrast agents in gel. The iDQC images obtained with echo-planar readout visualized the labeled cells effectively and with a higher contrast than seen in conventional GE images, especially at low planar resolutions and with thick slices. This implies that iDQC imaging with contrast agents could be a good alternative to conventional MR imaging for detecting labeled single cells or cell tracking under favorable conditions.


Subject(s)
Cell Tracking/methods , Dextrans , Macrophages/cytology , Magnetic Resonance Imaging/methods , Magnetite Nanoparticles , Animals , Cell Line , Contrast Media , Mice , Reproducibility of Results , Sensitivity and Specificity , Staining and Labeling/methods
8.
Nanotechnology ; 22(37): 375603, 2011 Sep 16.
Article in English | MEDLINE | ID: mdl-21852740

ABSTRACT

The graphite encapsulation of metal alloy magnetic nanoparticles has attracted attention for biological applications because of the high magnetization of the encapsulated particles. However, most of the synthetic methods have limitations in terms of scalability and economics because of the demanding synthetic conditions and low yields. Here, we show that well controlled graphite-encapsulated FeCo core-shell nanoparticles can be synthesized by a hydrothermal method, simply by mixing Fe/Co with sucrose as a carbon source. Various Fe/Co metal ratios were used to determine the compositional dependence of the saturation magnetization and relaxivity coefficient. Transmission electron microscopy indicated that the particle sizes were 7 nm. In order to test the capability of graphite-encapsulated FeCo nanoparticles as magnetic resonance imaging (MRI) contrast agents, these nanoparticles were solubilized in water by the nonspecific physical adsorption of sodium dodecylbenzene sulfonate.


Subject(s)
Cobalt/chemistry , Graphite/chemistry , Iron/chemistry , Magnetics , Metal Nanoparticles/chemistry , Nanotechnology/methods , Temperature , Benzenesulfonates/chemistry , Colloids , Contrast Media/chemistry , Magnetic Resonance Imaging , Metal Nanoparticles/ultrastructure , Spectrophotometry, Atomic , Spectroscopy, Fourier Transform Infrared , Spectrum Analysis, Raman , Water/chemistry , X-Ray Diffraction
9.
Org Lett ; 10(17): 3717-20, 2008 Sep 04.
Article in English | MEDLINE | ID: mdl-18651748

ABSTRACT

The chemodosimetric behavior of dichlorofluorescein derivatives toward Hg(2+) ions was investigated. Simple chemodosimetric systems showed selective and efficient signaling behaviors toward micromolar concentrations of Hg(2+) ions over other common interfering metal ions in an aqueous environment. The signaling mechanism is selective mercuration of the 4',5'-position of the xanthene moiety, which results in efficient chromogenic and fluorogenic signaling of Hg(2+) ions in aqueous environment.


Subject(s)
Fluoresceins/chemistry , Fluorescent Dyes/chemistry , Mercury/chemistry , Spectrometry, Fluorescence/methods , Cations, Divalent/chemistry , Magnetic Resonance Spectroscopy/methods , Mercury/analysis , Sensitivity and Specificity , Solutions , Spectrophotometry, Ultraviolet/methods , Water/chemistry
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