Various microfluidic features, such as traps, have been used to manipulate flows, cells, and other particles within microfluidic systems. However, these features often become undesirable in subsequent steps requiring different fluidic configurations. To meet the changing needs of various microfluidic configurations, we developed a reconfigurable microfluidic channel with movable sidewalls using mechanically discretized sidewalls of laterally aligned rectangular pins. The user can deform the channel sidewall at any time after fabrication by sliding the pins. We confirmed that the flow resistance of the straight microchannel could be reversibly adjusted in the range of 101–105 Pa s/μl by manually displacing one of the pins comprising the microchannel sidewall. The reconfigurable microchannel also made it possible to manipulate flows and cells by creating a segmented patterned culture of COS-7 cells and a coculture of human umbilical vein endothelial cells (HUVECs) and human lung fibroblasts (hLFs) inside the microchannel. The reconfigurable microfluidic device successfully maintained a culture of COS-7 cells in a log phase throughout the entire period of 216 h. Furthermore, we performed a migration assay of cocultured HUVEC and hLF spheroids within one microchannel and observed their migration toward each other.
This retrospective imaging study included 22,470 examinations of 12,265 persons who underwent brain magnetic resonance imaging(MRI)over 11 years during health check-ups at the health check-up center in Chunichi Hospital. All T1-, T2-, fluid attenuation inversion recovery-, and T2 * -weighted images were recorded and analyzed at every MRI examination. Of the 12,265 subjects(7,954 men and 4,311 women) , 66 (0.54%;53 men and 13 women)had incidental cerebral cavernous malformations(CCMs) . The frequency of CCMs in men(0.67%)was approximately twice as high as that in women(0.3%) . The observed frequencies for men and women reported recently in population-based CCM prevalence studies from other countries were similar;therefore, this study might indicate a more frequent tendency for CCMs in Japanese men.Thirty-four subjects harboring CCMs were followed by serial MRI examinations during the study period. Nine CCMs increased in size in this period, and 6 of them exhibited signal characteristics of hyperintensity on T1-weighted MR images.
Here we demonstrate a method that allows light-induced activation of voltagegated ion channels and the concurrent imaging of membrane potential changes using voltage-sensitive dyes. This light-induced voltage clamp (LIVC) method uses photostimulation through channelrhodopsin-2 (ChR2) to activate voltagegated ion channels. ChR2 allows light to be immediately transduced into a depolarizing ionic current, which in turn causes voltage-gated ion channels to open. In our system we coexpressed ChR2 either with the voltage-gated potassium channels hERG or hKv1.5 in cell lines and in Xenopus oocytes. In electrophysiological experiments we show that light-induced depolarization through ChR2 sufficed to activate hERG as well as hKv1.5 channels. We were further able to optically monitor the light-induced membrane de-and hyperpolarizations on a millisecond timescale with the voltage-sensitive RH421 and Annine6. The fluorescence readout reflected the dose-response relationships of the hERG blocker Terfenadine and the hKv1.5 inhibitor DPO-1 obtained from patch-clamp measurements. LIVC represents a solely optical technology with remote activation of the target voltage-gated ion channels by the delivery of a flash of blue light and simultaneous detection of their activity employing voltage-sensitive dyes. It combines the high-throughput of optical methods with the high-content of patch clamp concerning high temporal resolution, membrane potential control and repetitive stimulation.
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