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71.
Shinjyo Noriko Fuchino Hiroyuki Kawahara Nobuo Hishida Atsuyuki 《Journal of natural medicines》2018,72(3):774-778
Journal of Natural Medicines - The root of Angelica acutiloba Kitagawa is an important crude drug in Kampo medicines (traditional Japanese medicine). Chemical evaluation of crude drugs is crucial... 相似文献
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YongTae Kim Mark E. Lobatto Tomohiro Kawahara Bomy Lee Chung Aneta J. Mieszawska Brenda L. Sanchez-Gaytan Francois Fay Max L. Senders Claudia Calcagno Jacob Becraft May Tun Saung Ronald E. Gordon Erik S. G. Stroes Mingming Ma Omid C. Farokhzad Zahi A. Fayad Willem J. M. Mulder Robert Langer 《Proceedings of the National Academy of Sciences of the United States of America》2014,111(3):1078-1083
Therapeutic and diagnostic nanomaterials are being intensely studied for several diseases, including cancer and atherosclerosis. However, the exact mechanism by which nanomedicines accumulate at targeted sites remains a topic of investigation, especially in the context of atherosclerotic disease. Models to accurately predict transvascular permeation of nanomedicines are needed to aid in design optimization. Here we show that an endothelialized microchip with controllable permeability can be used to probe nanoparticle translocation across an endothelial cell layer. To validate our in vitro model, we studied nanoparticle translocation in an in vivo rabbit model of atherosclerosis using a variety of preclinical and clinical imaging methods. Our results reveal that the translocation of lipid–polymer hybrid nanoparticles across the atherosclerotic endothelium is dependent on microvascular permeability. These results were mimicked with our microfluidic chip, demonstrating the potential utility of the model system.Improving the design of nanomedicines is key for their success and ultimate clinical application (1). The accumulation of such therapeutic or diagnostic nanomaterials primarily relies on enhanced endothelial permeability of the microvasculature in diseased tissue (2). This holds true for a wide range of pathological conditions, including inflammation, atherosclerosis, and most notably, oncological disease (3–6). Although attributed to the enhanced permeability and retention (EPR) effect, the exact mechanism by which nanoparticles accumulate in tumors continues to be a topic of research (7, 8). The “leaky” vasculature of tumors, which facilitates the extravasation of nanoparticles from microvessels (9), is a heterogeneous phenomenon that varies between different tumor models and even more so in patients. Moreover, the exploitation of nanomedicines in other conditions with enhanced microvessel permeability has only recently begun to be studied in detail. For example, in the last 5 y, a small but increasing number of preclinical studies that apply nanoparticle therapy in atherosclerosis models has surfaced (10). Although several targeting mechanisms have been proposed (4), the exact mechanism by which nanoparticles accumulate in atherosclerotic plaques remains to be investigated, but is likely facilitated by highly permeable neovessels that penetrate into the plaque from the vasa vasorum (Fig. 1A), a network of microvessels that supplies the wall of larger vessels (11).Open in a separate windowFig. 1.Development of an endothelialized microfluidic device to probe nanoparticle translocation over a permeable microvessel. (A) Schematics of continuous normal capillaries surrounding the vessel wall as well as permeable capillaries that penetrate into the atherosclerotic plaque from the vasa vasorum. (B) Schematic of an endothelialized microfluidic device that consists of two-layer microfluidic channels that are separated by a porous membrane (3 μm pore) on which ECs are grown. (C) TEER was dynamically measured across the endothelial layer on the membrane between the upper and lower channels. (D) A well-established monolayer of the microvascular endothelium is formed at TEER ∼400 (Ω·cm2). (E) The monolayer becomes highly permeable when stimulated with the inflammatory mediator, TNF-α, as well as with shear stress, with disruption of intercellular junctional structures (i.e., adherens junctions) between ECs, as evidenced by patchy expression of VE–cadherin (green) in the image on the right versus the left. Blue depicts nuclei stained with DAPI. (Scale bar, 20 μm.) (F) FITC–albumin translocation through the endothelial monolayer increases when the chip is treated with TNF-α. (G) The chip with endothelium cultured in different culture media [base, +FBS, +growth factors (GFs)] for 6 h shows a decrease in TEER with increased FITC–albumin translocation. No cell indicates the membrane only. TEER was normalized to the level with no cells (membrane only). (H) Schematic and TEM image of PEGylated lipid-coated nanoparticles encapsulating PLGA-conjugated AuNCs and Cy5.5. The average size was 69.7 ± 14 nm, which was measured from TEM images. (Scale bar, 100 nm.) Details on labeling, synthesis, characterization, and large-scale production procedures can be found in Materials and Methods and Fig. S2.Advances in biomedical imaging allow the study of plaque-targeting nanoparticles in a dynamic fashion with exceptional detail (12, 13). Microchip technology has the potential to monitor nanoparticle behavior at the (sub)cellular level. Microfluidic chips in which endothelial cells (ECs) are grown in the channels can serve as unique in vitro test systems to study microvascular function and associated disorders (14–18). They allow the isolation of specific biological hallmarks relevant to nanoparticle accumulation, such as the leaky endothelium. In the current study, we validate the potential utility of our microchip technology to study nanoparticle translocation over the endothelium and combine this with in vivo and ex vivo multimodality imaging studies on a rabbit model to better understand nanoparticle targeting of atherosclerotic plaques. 相似文献
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Quantitative analysis of the spinal cord motoneuron under chronic compression: an experimental observation in the mouse 总被引:5,自引:0,他引:5
Hisatoshi Baba Yasuhisa Maezawa Shinichi Imura Norio Kawahara Kenji Nakahashi Katsuro Tomita 《Journal of neurology》1996,243(2):109-116
We investigated quantitative changes in spinal cord motoneurons following chronic compression using a mouse model of cervical
cord compression. Twenty-five tiptoe-walking Yoshimura (twy) mice with calcified mass lesions compressing the spinal cord
posterolaterally at the C1–C2 vertebral levels were compared with five Institute of Cancer Research (ICR) mice that served
as controls. Spinal cord motoneurons in the anterior grey horn between the C1 and C3 spinal cord segments were Nissl-stained
and counted topographically and then analysed in relation to the extent of spinal cord compression. The number of motoneurons
in C1–C3 spinal cord segments decreased significantly with a linear correlation with the transverse area of the spinal cord
when the cord was compressed to 50–70% of control values. A significant reduction in the number of motoneurons occurred at
the C2–C3 spinal cord segment compressed at the C1–C2 vertebral level. In contrast, at the level rostral to the C1 vertebra,
the number of motoneurons increased significantly in proportion to the magnitude of compression. The current study demonstrates
that a number of neurons, morphologically consistent with anterior horn cells, were observed at a rostral site absolutely
free of external compression where no such cells normally exist. 相似文献
78.
Comparative neurophysiological and neuropathological studies were performed in two children who were found as a very rare multiple system degeneration (MSD) in brainstem and cerebellum. One young child suffered from both multiple system and retinal degeneration and another child had widespread multiple system degeneration associated with lipoprotein disorder and liver cirrhosis. The results of the neurophysiological studies indicated dysfunction of the brainstem and the peripheral nerves and were well correlated with the clinical course. CT studies showed progressive cerebellar atrophy. Since serial neurophysiological and CT studies were compatible with the neuropathological findings, the combination of these examinations seems to be quite valuable for understanding the pathogenesis and monitoring the progression of MSD in childhood. 相似文献
79.
Katsuya Tamai Kenji Kawate Ikuo Kawahara Yoshinori Takakura Kazuhiko Sakaki 《Journal of orthopaedic science》2009,14(2):204-209
Background For orthopedic implants, infection is a serious problem. Therefore, we considered an implant with antimicrobial ability can
prevent infection. We tried to coat a titanium alloy surface with Novaron, a commercially available inorganic antimicrobial.
The purpose of this study was to analyze the differences among the surfaces of materials coated using different processing
pressures of the working gas and analysis of the antimicrobial activity.
Methods One of the inorganic antimicrobials Novaron (grade VZ 600) was applied to titanium alloy (Ti6Al4V) plates. This antimicrobial
has limited heat resistance, so we used cold spray technology to coat the titanium alloy with it. The principle of cold spray
technology is spraying a powder in a high-velocity gas jet, accelerated by adiabatic expansion, against a substrate. Scanning
electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS) were used to analyze the differences among the surfaces
of materials coated using different processing pressures of the working gas. The Japanese Industrial Standard (JIS) method
(JIS Z2801: 2000) was used to analyze the antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Antimicrobial activity was analyzed only for the sample coated at 3.0 MPa.
Results The SEM and EDS results indicated that when the pressure of the working gas was increased, the antimicrobial coated the titanium
adequately. This material showed good effects against S. aureus and P. aeruginosa and some effect for K. pneumoniae.
Conclusions Antimicrobial implants represent a preventive method against infection. There is a possibility of using them not only for
clean operations but also for operations with suspected bacterial contamination, such as fixation of slight compound fractures. 相似文献
80.
Shinji Akamine Katsunobu Kawahara Akihiro Nakamura Takao Takahashi Satoshi Yamamoto Hiroyoshi Ayabe Masao Tomita 《Surgery today》1995,25(7):654-656
We describe herein the successful utilization of a video-assisted thoracic surgical approach to repair Morgagni's hernia. The patient was a 62-year-old woman in whom a routine chest X-ray had revealed an asymptomatic mass, which was presumed to be a pericardial lipoma or Morgagni's hernia. The video-assisted thoracic surgical approach was combined with a right submammary minithoracotomy to successfully repair the hernia without performing a laparotomy. The patient's postoperative course was uneventful and she was discharged 14 days after surgery. Thus, we believe that video-assisted thoracic surgery may be a useful and effective method for repairing Morgagni's hernia. 相似文献