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contrast agents

Zheyu Shen, Aiguo Wu, Xiaoyuan Chen
Magnetic iron oxide nanoparticles (MIONs) have attracted enormous attention due to their wide applications, including magnetic separation, magnetic hyperthermia and as contrast agents for magnetic resonance imaging (MRI). This review article introduces the methods of synthesizing MIONs, and their application as MRI contrast agents. Currently, many methods have been reported for the synthesis of MIONs. Herein, we only focus on the liquid-based synthesis methods including aqueous phase methods and organic phase methods...
October 24, 2016: Molecular Pharmaceutics
Kaien Liu, Zhijian Ji, Wei Ren
The consensus problem for second-order multiagent systems with absolute velocity damping under directed topologies is investigated. In contrast to the existing results, which rely on a sufficiently large common absolute velocity damping gain above a lower bound dependent on global information, this paper focuses on novel algorithms to overcome this limitation. A novel consensus algorithm, where different agents use different absolute velocity damping gains, is first proposed. In the absence of delays, based on a system transformation method, the consensus problem for second-order multiagent systems is converted into that for first-order multiagent systems with the agent number doubled...
October 21, 2016: IEEE Transactions on Cybernetics
Paul S Sheeran, Naomi Matsuura, Mark A Borden, Ross Williams, Terry O Matsunaga, Peter N Burns, Paul A Dayton
Continued advances in the field of ultrasound and ultrasound contrast agents have created new approaches to imaging and medical intervention. Phase-shift perfluorocarbon droplets, which can be vaporized by ultrasound energy to transition from the liquid to the vapor state, are one of the most highly researched alternatives to clinical ultrasound contrast agents (i.e. microbubbles). In this review, part of a special issue on methods in biomedical ultrasonics, we survey current techniques to prepare ultrasound-activated nanoscale phase-shift perfluorocarbon droplets, including sonication, extrusion, homogenization, microfluidics, and microbubble condensation...
October 20, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Hye Jin Yoo, Sung Hwan Hong, Hye Yeon Oh, Ja-Young Choi, Hee Dong Chae, Joong Mo Ahn, Heung Sik Kang
Purpose To determine the agreement of fat-suppressed (FS) fluid-attenuated inversion-recovery (FLAIR) magnetic resonance (MR) imaging and contrast material-enhanced (CE) T1-weighted MR imaging for the assessment of peripatellar synovitis. Materials and Methods The institutional review board approved this retrospective study and waived the requirement for patient informed consent. Thirty-three patients with knee pain underwent 3-T MR imaging. The protocol consisted of routine clinical sequences followed by the FLAIR FS sequence (inversion time, 2200 msec) and CE T1-weighted imaging...
October 24, 2016: Radiology
Julia L Monteiro, Paula F Carneiro, Petteri Elsner, Dominique Roberge, Peter G M Wuts, Kathrin Kurjan, Bernhard Gutmann, C Oliver Kappe
Herein, we report an operationally simple and rapid continuous flow radical C─C bond formation under Minisci-type reaction conditions. The transformations are performed at or below room temperature employing hydrogen peroxide (H2O2) and dimethylsulfoxide (DMSO) as reagents in the presence of an Fe(II) catalyst. For electron rich aromatic and heteroaromatic substrates C─C bond formation proceeds satisfactorily with electrophilic radicals including ∙CF3, ∙C4F9, ∙CH2CN and ∙CH2CO2Et. In contrast, electron poor substrates exhibit minimal reactivity...
October 24, 2016: Chemistry: a European Journal
S Cacanyiova, A Berenyiova, F Kristek
Cardiovascular studies have confirmed that hydrogen sulphide (H(2)S) is involved in various signaling pathways in both physiological and pathological conditions, including hypertension. In contrast to nitric oxide (NO), which has a clear vasorelaxant action, H(2)S has both vasorelaxing and vasoconstricting effects on the cardiovascular system. H(2)S is an important antihypertensive agent, and the reduced production of H(2)S and the alterations in its functions are involved in the initiation of spontaneous hypertension...
October 24, 2016: Physiological Research
Aby Cheruvathoor Poulose, Srivani Veeranarayanan, M Sheikh Mohamed, Rebeca Romero Aburto, Trevor Mitcham, Richard R Bouchard, Pulickel M Ajayan, Yasushi Sakamoto, Toru Maekawa, D Sakthi Kumar
Hypermethylated cancer populations are hard to treat due to their enhanced chemo-resistance, characterized by aberrant methylated DNA subunits. Herein, we report on invoking response from such a cancer lineage to chemotherapy utilizing multifunctional copper telluride (Cu2-XTe) nanocubes (NCs) as photothermal and photodynamic agents, leading to significant anticancer activity. The NCs additionally possessed photoacoustic and X-ray contrast imaging abilities that could serve in image-guided therapeutic studies...
October 24, 2016: Scientific Reports
Jun-Qing Situ, Xiao-Juan Wang, Xiu-Liang Zhu, Xiao-Ling Xu, Xu-Qi Kang, Jing-Bo Hu, Chen-Ying Lu, Xiao-Ying Ying, Ri-Sheng Yu, Jian You, Yong-Zhong Du
Specific delivery of chemotherapy drugs and magnetic resonance imaging (MRI) contrast agent into tumor cells is one of the issues to highly efficient tumor targeting therapy and magnetic resonance imaging. Here, A54 peptide-functionalized poly(lactic-co-glycolic acid)-grafted dextran (A54-Dex-PLGA) was synthesized. The synthesized A54-Dex-PLGA could self-assemble to form micelles with a low critical micelle concentration of 22.51 μg. mL(-1) and diameter of about 50 nm. The synthetic A54-Dex-PLGA micelles can encapsulate doxorubicin (DOX) as a model anti-tumor drug and superparamagnetic iron oxide (SPIO) as a contrast agent for MRI...
October 24, 2016: Scientific Reports
Shuai Yu, Bingbing Cheng, Tingfeng Yao, Cancan Xu, Kytai T Nguyen, Yi Hong, Baohong Yuan
Recently, we developed a new technology, ultrasound-switchable fluorescence (USF), for high-resolution imaging in centimeter-deep tissues via fluorescence contrast. The success of USF imaging highly relies on excellent contrast agents. ICG-encapsulated poly(N-isopropylacrylamide) nanoparticles (ICG-NPs) are one of the families of the most successful near-infrared (NIR) USF contrast agents. However, the first-generation ICG-NPs have a short shelf life (<1 month). This work significantly increases the shelf life of the new-generation ICG-NPs (>6 months)...
October 24, 2016: Scientific Reports
Ming Ma, Fei Yan, Minghua Yao, Zijun Wei, Dongliang Zhou, Heliang Yao, Hairong Zheng, Hangrong Chen, Jianlin Shi
Entirely differing from the common templating-based multistep strategy in fabricating multifunctional hollow mesoporous silica nanoparticles (HMSNs), a facile and template-free synthetic strategy has been established in constructing a unique hollow/mesoporous organosilica nanocapsule concurrently encapsulating both isopentyl acetate (PEA) liquid and superparamagnetic iron oxides inside (denoted as PEA@OSNCs). This novel material exhibits ultrasmall and uniform particle size (~82 nm), high surface area (~534 m2 g-1) and excellent colloidal stability in aqueous solution...
October 24, 2016: ACS Applied Materials & Interfaces
Liting Deng, Wan-Hung Lee, Zhili Xu, Alexandros Makriyannis, Andrea G Hohmann
Neuropathic pain impacts approximately 3-4.5% of the global population and remains an unresolved health problem. The management of neuropathic pain has two distinct goals-prevention of development and control of established neuropathic pain. We examined the impact of both prophylactic and therapeutic treatments with the tricyclic antidepressant desipramine on the development and maintenance of toxic neuropathic pain induced by the chemotherapeutic agent paclitaxel. We also investigated the involvement of endogenous analgesic (i...
October 20, 2016: Pharmacological Research: the Official Journal of the Italian Pharmacological Society
Pierre-Henri Conze, Vincent Noblet, François Rousseau, Fabrice Heitz, Vito de Blasi, Riccardo Memeo, Patrick Pessaux
PURPOSE: Toward an efficient clinical management of hepatocellular carcinoma (HCC), we propose a classification framework dedicated to tumor necrosis rate estimation from dynamic contrast-enhanced CT scans. Based on machine learning, it requires weak interaction efforts to segment healthy, active and necrotic liver tissues. METHODS: Our contributions are two-fold. First, we apply random forest (RF) on supervoxels using multi-phase supervoxel-based features that discriminate tissues based on their dynamic in response to contrast agent injection...
October 22, 2016: International Journal of Computer Assisted Radiology and Surgery
Elena Milla, Oana Stirbu, Isabel Jimenez Franco, Santiago J García Hernández, Jose Rios, Susana Duch
PURPOSE: Retrospective, pilot study to determine whether nepafenac treatment pre- and postcataract surgery in glaucoma patients using topical hypotensive agents minimized cystoid macular edema by comparing pre- and postsurgical foveal characteristics, as in some cases these agents cannot be withdrawn and, hypothetically, their inflammatory effect on the fovea could be neutralized by the addition of nepafenac. METHODS: Patients were divided into two subgroups depending on whether or not topical nepafenac was added to the surgical protocol (NEP = nepafenac group and nNEP = non nepafenac group)...
October 22, 2016: International Ophthalmology
Yang Sheng, Lun-De Liao, Aishwarya Bandla, Yu-Hang Liu, Jun Yuan, Nitish Thakor, Mei Chee Tan
Near-infrared photoacoustic (PA) imaging is an emerging diagnostic technology that utilizes the tissue transparent window to achieve improved contrast and spatial resolution for deep tissue imaging. In this study, we investigated the enhancement effect of the SiO2 shell on the PA property of our core/shell rare-earth nanoparticles (REs) consisting of an active rare-earth doped core of NaYF4:Yb,Er (REDNPs) and an undoped NaYF4 shell. We observed that the PA signal amplitude increased with SiO2 shell thickness...
January 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
A A Prihanto, M Wakayama
l-Asparaginase (EC is an enzyme that catalyzes the hydrolysis of l-asparagine to l-aspartic acid. This enzyme has an important role in medicine and food. l-Asparaginase is a potential drug in cancer therapy. Furthermore, it is also applied for reducing acrylamide, a carcinogenic compound in baked and fried foods. Until now, approved l-asparaginases for both applications are few due to their lack of appropriate properties. As a result, researchers have been enthusiastically seeking new sources of enzyme with better performance...
2016: Advances in Food and Nutrition Research
Michael L Schulte, Matthew R Hight, Gregory D Ayers, Qi Liu, Yu Shyr, M Kay Washington, H Charles Manning
PURPOSE: This study aimed to study whether cancer cells possess distinguishing metabolic features compared with surrounding normal cells, such as increased glutamine uptake. Given this, quantitative measures of glutamine uptake may reflect critical processes in oncology. Approximately, 10 % of patients with colorectal cancer (CRC) express BRAF (V600E) , which may be actionable with selective BRAF inhibitors or in combination with inhibitors of complementary signaling axes. Non-invasive and quantitative predictive measures of response to these targeted therapies remain poorly developed in this setting...
October 21, 2016: Molecular Imaging and Biology: MIB: the Official Publication of the Academy of Molecular Imaging
Gabor Nagy, Viktoria Baksa, Alexandra Kiss, Melinda Turani, Gaspar Banfalvi
The toxicity of gadolinium is reduced by chelating agents that render this heavy metal into contrast complexes used for medical magnetic resonance imaging. However, the dissociation of gadolinium chelates is known to generate Gd(3+) ions, the cellular toxicity of which has not been tested in details. The cytotoxic effects of Gd(III) ions were evaluated by monitoring the proliferation, measuring the cellular motility and following chromatin changes in various cell lines upon Gd(3+) treatment. Measurements applied long-term scanning microscopy and a perfusion platform that replaced the medium with test solutions, bypassed physical contact with the cell culture during experiments, and provided uninterrupted high time-resolution time-lapse photomicrography for an extended period of time...
October 22, 2016: Apoptosis: An International Journal on Programmed Cell Death
Bartosz Roszniowski, Agnieszka Latka, Barbara Maciejewska, Dieter Vandenheuvel, Tomasz Olszak, Yves Briers, Giles S Holt, Miguel A Valvano, Rob Lavigne, Darren L Smith, Zuzanna Drulis-Kawa
Burkholderia phage AP3 (vB_BceM_AP3) is a temperate virus of the Myoviridae and the Peduovirinae subfamily (P2likevirus genus). This phage specifically infects multidrug-resistant clinical Burkholderia cenocepacia lineage IIIA strains commonly isolated from cystic fibrosis patients. AP3 exhibits high pairwise nucleotide identity (61.7 %) to Burkholderia phage KS5, specific to the same B. cenocepacia host, and has 46.7-49.5 % identity to phages infecting other species of Burkholderia. The lysis cassette of these related phages has a similar organization (putative antiholin, putative holin, endolysin, and spanins) and shows 29-98 % homology between specific lysis genes, in contrast to Enterobacteria phage P2, the hallmark phage of this genus...
October 21, 2016: Applied Microbiology and Biotechnology
Gyeung Mi Seon, Mi Hee Lee, Byeong-Ju Kwon, Min Sung Kim, Min-Ah Koo, Dohyun Kim, Young Seomun, Jong-Tak Kim, Jong-Chul Park
: Although a number of natural materials have been used as hemostatic agents, many substances do not act quickly enough. Here, we created a novel dressings using collagen and chitosan with recombinant batroxobin (r-Bat) to promote faster and more effective hemostasis. We hypothesized that r-Bat would promote synergetic blood coagulation because it contains a blood coagulation active site different than those of collagen and chitosan. Our results suggest that each substances can maintain hemostatic properties while in the mixed dressings and that our novel hemostatic dressings promotes potent control of bleeding, as demonstrated by a whole blood assay and rat hemorrhage model...
October 18, 2016: Acta Biomaterialia
Sayani Mitra, Silke Schicktanz
BACKGROUND: During a commercial surrogacy arrangement, the event of embryo transfer can be seen as the formal starting point of the arrangement. However, it is common for surrogates to undergo a failed attempt at pregnancy conception or missed conception after an embryo transfer. This paper attempts to argue that such failed attempts can be understood as a loss. It aims to reconstruct the experiences of loss and grief of the surrogates and the intended parents as a consequence of their collective failure to conceive a surrogate pregnancy...
September 19, 2016: Philosophy, Ethics, and Humanities in Medicine: PEHM
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