Vessel wall imaging in the diagnosis of antiphospholipid syndrome presenting as Moyamoya syndrome-A case report.

Objectives: We describe a case of anti-phospholipid syndrome (APLS) vasculopathy presenting with Moyamoya syndrome (MMS) and show the associated intracranial vessel wall MRI (VWI) findings. Methods: A 37-year-old-woman presented with acute onset dizziness and left-sided weakness. Neurologic exam revealed a left facial droop and left hemiparesis. She underwent a comprehensive laboratory work-up for stroke. Neuroimaging included a CT head, CT angiogram, VWI, and digital subtraction angiography. Results: Work-up revealed a triple-positive APLS antibody profile. CT of the head showed an acute right basal ganglia infarction and right frontal subarachnoid hemorrhage. CT angiogram revealed severe stenosis of the right internal carotid artery terminus in a Moyamoya pattern. Intracranial VWI showed long-segment concentric vessel wall thickening and homogeneous vessel wall enhancement and T2-hyperintense wall edema of the stenotic right ICA terminus, M1 middle cerebral artery, and A1 anterior cerebral artery. She was treated with long-term anticoagulation with warfarin and a right superficial temporal artery to middle cerebral artery bypass. Discussion: We present intracranial VWI features of vessel wall pathology in a patient with primary APLS presenting with MMS.

1-Million droplet array with wide-field fluorescence imaging for digital PCR.

Digital droplet reactors are useful as chemical and biological containers to discretize reagents into picolitre or nanolitre volumes for analysis of single cells, organisms, or molecules. However, most DNA based assays require processing of samples on the order of tens of microlitres and contain as few as one to as many as millions of fragments to be detected. Presented in this work is a droplet microfluidic platform and fluorescence imaging setup designed to better meet the needs of the high-throughput and high-dynamic-range by integrating multiple high-throughput droplet processing schemes on the chip. The design is capable of generating over 1-million, monodisperse, 50 picolitre droplets in 2-7 minutes that then self-assemble into high density 3-dimensional sphere packing configurations in a large viewing chamber for visualization and analysis. This device then undergoes on-chip polymerase chain reaction (PCR) amplification and fluorescence detection to digitally quantify the sample's nucleic acid contents. Wide-field fluorescence images are captured using a low cost 21-megapixel digital camera and macro-lens with an 8-12 cm(2) field-of-view at 1× to 0.85× magnification, respectively. We demonstrate both end-point and real-time imaging ability to perform on-chip quantitative digital PCR analysis of the entire droplet array. Compared to previous work, this highly integrated design yields a 100-fold increase in the number of on-chip digitized reactors with simultaneous fluorescence imaging for digital PCR based assays.

Tunable 3D droplet self-assembly for ultra-high-density digital micro-reactor arrays.

We present a tunable three-dimensional (3D) self-assembled droplet packing method to achieve high-density micro-reactor arrays for greater imaging efficiency and higher-throughput chemical and biological assays. We demonstrate the capability of this platform's high-density imaging method by performing single molecule quantification using digital polymerase chain reaction, or digital PCR, in multiple self-assembled colloid-like crystal lattice configurations. By controlling chamber height to droplet diameter ratios we predictively control three-dimensional packing configurations with varying degrees of droplet overlap to increase droplet density and imaging sensor area coverage efficiency. Fluorescence imaging of the densely packed 3D reactor arrays, up to three layers high, demonstrates high throughput quantitative analysis of single-molecule reactions. Now a greater number of microreactors can be observed and studied in a single picture frame without the need for confocal imaging, slide scanners, or complicated image processing techniques. Compared to 2D designs, tunable 3D reactor arrays yield up to a threefold increase in density and use 100% of the sensor's imaging area to enable simultaneous imaging a larger number of reactions without sacrificing digital quantification performance. This novel approach provides an important advancement for ultra-high-density reactor arrays.

Analytical significance of encroachment in multiplexed bead-based flow cytometric assays.

Multiplexed bead-based assays, using fluorescent dye-encoded beads, are finding widespread use in various profiling studies. The need to measure multiple quantitative responses simultaneously, the development of less expensive commercial flow systems, and the ease and cost effectiveness of manufacturing bead profiling kits of varied composition have all contributed to the popularity of this assay format. Maximizing the level of multiplexing in these assays requires tight spacing of fluorescent bead populations, and this leads to some degree of overlap or "encroachment" between populations. The degree to which encroachment affects analyte signal determinations depends upon both the extent of overlap and the relative analyte signals associated with the populations. In the work reported here, the impact of encroachment upon analyte signal for a subset of beads belonging to a multiplexed cytokine assay has been modeled and empirically evaluated.