No abstract

Background: The outbreak of 2019 novel coronavirus disease in Wuhan, China, has spread rapidly worldwide. In the early stage, we encountered a small but meaningful number of patients who were unintentionally scheduled for elective surgeries during the incubation period of COVID-19. We intended to describe their clinical characteristics and outcomes. Methods: We retrospectively analyzed the clinical data of 34 patients underwent elective surgeries during the incubation period of COVID-19 at

We demonstrate a strategy for the synthesis of multifunctional mesoporous silica nanoparticles. These uniform tumblerlike nanocomposites, which simultaneously possess magnetic, luminescent, and porous properties, have great potential in biomedical applications.

We demonstrate a sol-gel approach, using a water-in-oil microemulsion as the template, for the synthesis of hollow and yolk/shell silica nanospheres, which can encapsulate pre-formed hydrophobic nanoparticles, and we then explore these multifunctional hollow nanospheres in cell-labeling applications.

Cells have many advantages as therapeutic agents. They are able to carry out complex functions, as in stem cell [1] or immune cell therapy. [2] For effective therapy, the delivered cells must carry long-lived tracking agents for monitoring the position and fate of the injected cells. At present, monitoring is often carried out by slow histological analysis, which requires tissue biopsy. Recently, the development of noninvasive real-time tracking of injected cells has attracted a lot of attention for its clinical potential. Fluorescent nanomaterials have been successfully utilized as labels in biological and medical applications for imaging [3,4] and diagnostic purposes. [5][6][7] The limited capability of the fluorescence technique in detecting deep tissues restricts the collection of information in vivo. Magnetic resonance imaging (MRI), one of the most important noninvasive imaging techniques, has been widely used for clinical diagnosis [8] and biomedical research. However, its sensitivity is relatively low for cellularlevel applications. [9] Hence, the synthesis of a new MRI con-trast agent [10][11][12][13] with high sensitivity would be of great interest.Recently, the development of a nanomaterial-based probe with multifunctionalities has become a very active field. Preferably, the functionalities should combine the advantages of MRI in noninvasiveness, fluorescence in high sensitivity and resolution, a surface functional group for targeting, and the ability to deliver drugs locally. Among these, the carrying of good and long-lived MRI contrast agents would be the most useful. Our interest is in developing a nanoparticle form of mesoporous silica, which has some unique properties, such as rigid structure, large pore volume, uniform pore size, great surface-modification capability, [14] and good biocompatibility. It has also been demonstrated as a biomarker [15,16] and a drug carrier. [17][18][19] Previously, we reported multimodal tumblerlike mesoporous silica, which carries a magnetic iron oxide nanoparticle as a T 2 contrast agent (T 1 and T 2 = magnetic relaxation times) and a fluorescent dye. [20] However, the T 2 agent often gives poor contrast in dark areas, such as the liver. Herein, we report a new multifunctional mesoporous silica nanorod that possesses green fluorescence and paramagnetism, and could serve as a good contrast agent in T 1 and T 2 imaging.The multimodality of nanoparticle-based monitoring agents has been developed before. However, very few have been demonstrated as a platform in cell monitoring. [21] There are several different combinations of luminescent materials, MRI contrast agents, and support. The iron oxide nanoparticle, a typical T 2 contrast agent, has been demonstrated to be a multimodal probe by surface functionalization with Cy5.5 dye and chlorotoxin to detect gliomas. [22] Santra and co-workers also developed novel multifunctional probes by encapsulating Gd-TSPETE (n-trimethoxysilylpropyl)ethyldiamine triacetic acid trisodium salt) and CdSe:Mn/ZnS core-shell quantum dots o...

Functional magnetic resonance imaging (fMRI) has revolutionized investigations of brain functions. Increases in fMRI signals

Postischemic cerebral blood flow and blood volume changes have been associated with angiogenesis; nevertheless, the spatiotemporal changes in vascular permeability, vascular density, and vessel size have not been investigated. Here we report a prolonged increase in vascular permeability from day 3 to day 21 after ischemia, in particular in the reperfused outer cortical layers and leptomeninges. Increased cerebral blood volume (CBV) was observed from day 3 to day 14, whereas increased blood volume in small vessels, primarily capillaries, was noticed from day 7 to day 14 in the reperfused cortex. An initial decrease in vascular density and a reciprocal increase in vessel size were observed within the reperfused cortex at days 1 and 3 after ischemia. Immunohistological analysis confirmed a similar decrease in microvessel density and an increase in vessel size in vessels with a diameter greater than 30 microm. These large-sized vessels exhibited intense basic fibroblast growth factor and endothelial nitric oxide synthase immunoreactivity, suggesting the growth of collateral vessels. By contrast, a late increase in vascular density was noticed in the reperfused outer cortex at days 14 and 21 after ischemia. Together, these findings suggest that the early phase of CBV increase is likely because of the improvement in collateral circulation, whereas the late phase of CBV increase is attributed to the surge of angiogenesis.

Nuclear accumulation of AMPK-α1 induces brain atrophy, neuronal loss, and formation of Htt aggregates in a Huntington’s disease model.