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At least 253 records · Page 14Linked to original sources
PubMed1998

Microlissencephaly.

An inbred Arab family with three neonates affected by microlissencephaly syndrome is reported. Brain magnetic resonance imaging in the index case revealed very thin brain mantle with agyria-pachygyria, agenesis of the corpus callosum, and hypoplasia of the brainstem and cerebellum. All three neonates had microcephaly, arthrogryposis multiplex congenita, and micropenis. The presence of three affected newborn infants in a consanguineous family suggests an autosomal-recessive mode of inheritance of this syndrome. The spectrum of microlissencephaly syndrome is reviewed.

Abnormalities, Multiple↗
PubMed2002

Simultaneous analysis of eight human Th1/Th2 cytokines using microarrays.

The adaptive immune system induces T cells to change from a naive phenotype to a Th1/Th2 phenotype each of which produce characteristic types of cytokines. Knowledge of whether a specific immune response is Th1 or Th2 is a useful indicator for diseases with basis in immune function disorder. An assay that can rapidly analyze multiple cytokines indicative of these two cell types from small sample quantities can be an extremely useful research and diagnostic tool. Silanized glass slides were printed with multiple arrays of capture antibodies to detect eight different cytokines involved in the Th1/Th2 response along with control proteins for assessing assay performance. Arrays were developed by sequential addition of known antigen amounts, detector antibodies and a fluorescent detection system followed by imaging and quantification. These arrays were used to determine the specificity, sensitivity and reproducibility of the assay and the performance compared with conventional ELISA. This multiplexed assay is able to measure human Th1/Th2 cytokines in sample volumes lower than 20 microl. The assay sensitivity for the eight cytokines range from 0.3 microg/l for IL-4 to 6.4 microg/l for IL-5 which are either comparable to or higher than those reported for conventional ELISA or bead-based multiplex ELISA methods. This assay can be automated to measure expression levels of multiple Th1/Th2 cytokines simultaneously from tens to hundreds of biological samples. This assay platform is more sensitive and has a larger dynamic range as compared to a conventional ELISA in addition to significantly reducing the time and cost of assay. This platform provides a versatile system to rapidly quantify a wide variety of proteins in a multiplex format.

Cytokines↗
PubMedDate not supplied

Pegylated, steptavidin-conjugated quantum dots are effective detection elements for reverse-phase protein microarrays.

Protein microarray technologies provide a means of investigating the proteomic content of clinical biopsy specimens in order to determine the relative activity of key nodes within cellular signaling pathways. A particular kind of protein microarray, the reverse-phase microarray, is being evaluated in clinical trials because of its potential to utilize limited amounts of cellular material obtained through biopsy. Using this approach, cellular lysates are arrayed in dilution curves on nitrocellulose substrates for subsequent probing with antibodies. To improve the sensitivity and utility of reverse-phase microarrays, we tested whether a new reporter technology as well as a new detection instrument could enhance microarray performance. We describe the use of an inorganic fluorescent nanoparticle conjugated to streptavidin, Qdot 655 Sav, in a reverse-phase protein microarray format for signal pathway profiling. Moreover, a pegylated form of this bioconjugate, Qdot 655 Sav, is found to have superior detection characteristics in assays performed on cellular protein extracts over the nonpegylated form of the bioconjugate. Hyperspectral imaging of the quantum dot microarray enabled unamplified detection of signaling proteins within defined cellular lysates, which indicates that this approach may be amenable to multiplexed, high-throughput reverse-phase protein microarrays in which numerous analytes are measured in parallel within a single spot.

Calibration↗
PubMed2003

Electron density characterization by use of a broadband x-ray-compatible wave-front sensor.

The use of a Hartmann wave-front sensor to accurately measure the line-integrated electron density gradients formed in laser-produced and z-pinch plasma experiments is examined. This wave-front sensor may be used with a soft-x-ray laser as well as with incoherent line emission at multikilovolt x-ray energies. This diagnostic is significantly easier to use than interferometery and moiré deflectometry, both of which have been demonstrated with soft-x-ray lasers. This scheme is experimentally demonstrated in the visible region by use of a Shack-Hartmann wave-front sensor and a liquid-crystal spatial light modulator to simulate a phase profile that could occur when an x-ray probe passes through a plasma. The merits of using a Hartmann sensor include a wide dynamic range, broadband or low-coherence-length light capability, high x-ray efficiency, two-dimensional gradient determination, multiplexing capability, and experimental simplicity. Hartmann sensors could also be utilized for wavelength testing of extreme-ultraviolet lithography components and x-ray phase imaging of biological specimens.

Journal Article↗
PubMed2006

Pulsed digital holography system recording ultrafast process of the femtosecond order.

We report, for the first time to our knowledge, a pulsed digital microholographic system with spatial angular multiplexing for recording the ultrafast process of the femtosecond order. The optimized design of the two sets of subpulse-train generators in this system makes it possible to implement a digital holographic recording with spatial angular multiplexing of a frame interval of the femtosecond order, while keeping the incident angle of the object beams unchanged. Three pairs of amplitude and phase images from the same view angle digitally reconstructed by the system demonstrated the ultrafast dynamic process of laser-induced ionization of ambient air at a wavelength of 800 nm, with a time resolution of 50 fs and a frame interval of 300 fs.

Journal Article↗
PubMed2000

Multiple channel phased arrays for echo planar imaging.

A new interface combining phased arrays and echo-planar imaging (EPI) technologies was developed for two channel breast MR EPI applications. A detailed design for a dual-channel, EPI-compatible, phased array breast coil is described. EPI digital data multiplexing, signal controlling and sampling schemes are also presented. Results from breast phantoms and patients demonstrate a 55% improvement in signal-to-noise ratio when compared to a conventional two-loop, single channel coil configuration. This method can be easily expanded to a four or more channel, EPI-compatible, phased array system to improve field-of-view coverage and signal-to-noise ratio.

Biomedical Engineering↗
PubMed2004

Optical coding of mammalian cells using semiconductor quantum dots.

Cell-based assays are widely used to screen compounds and study complex phenotypes. Few methods exist, however, for multiplexing cellular assays or labeling individual cells in a mixed cell population. We developed a generic encoding method for cells that is based on peptide-mediated delivery of quantum dots (QDs) into live cells. The QDs are nontoxic and photostable and can be imaged using conventional fluorescence microscopy or flow cytometry systems. We created unique fluorescent codes for a variety of mammalian cell types and show that our encoding method has the potential to create > 100 codes. We demonstrate that QD cell codes are compatible with most types of compound screening assays including immunostaining, competition binding, reporter gene, receptor internalization, and intracellular calcium release. A multiplexed calcium assay for G-protein-coupled receptors using QDs is demonstrated. The ability to spectrally encode individual cells with unique fluorescent barcodes should open new opportunities in multiplexed assay development and greatly facilitate the study of cell/cell interactions and other complex phenotypes in mixed cell populations.

Animals↗
PubMed1989

The Aberdeen Impedance Imaging System.

The Aberdeen Impedance Imaging System is designed to reconstruct 2 dimensional images of the average distribution of the amplitude and phase of the complex impedance within a 3 dimensional region. The system uses the four electrode technique in a 16 electrode split-array. The system hardware consists of task-orientated electronic modules for: driving a constant current, multiplexing the current drive, demultiplexing peripheral voltages, differential amplification, phase sensitive detection and low-pass filtration, digitisation with a 14 bit analog to digital converter (ADC), and -control logic for the ADC and multiplexors. A BBC microprocessor (Master series), initiates a controlled sequence for the collection of a number of data sets which are averaged and stored on disk. Image reconstruction is by a process of convolution-backprojection similar to the fan-beam reconstruction of computerised tomography and is also known as Equipotential Backprojection. In imaging impedance changes associated with fracture healing the changes may be large enough to allow retrieval of both the amplitude and phase of the complex impedance. Sequential imaging of these changes would necessitate monitoring electronic and electrode drift by imaging an equivalent region of the contralateral limb. Differential images could be retrieved when the image of the normal limb is the image template. Better characterisation of tissues would necessitate a cleaner retrieval of the quadrature signal.

Adult↗
PubMed2001

Evaluation of three-dimensional microchannel glass biochips for multiplexed nucleic acid fluorescence hybridization assays.

Three-dimensional, flow-through microchannel glass substrates have a potential for enhanced performance, including increased sensitivity and dynamic range, over traditional planar substrates used in medium-density microarray platforms. This paper presents a methodology for the implementation of multiplexed nucleic acid hybridization fluorescence assays on microchannel glass substrates. Fluorescence detection was achieved, in a first instance, using conventional low-magnification microscope objective lenses, as imaging optics whose depth-of-field characteristics match the thickness of the microchannel glass chip. The optical properties of microchannel glass were shown, through experimental results and simulations, to be compatible with the quantitative detection of heterogeneous hybridization events taking place along the microchannel sidewalls, with detection limits for oligonucleotide targets in the low-attomole range.

Base Sequence↗
PubMed1982

On-line cardiac mapping: an analog approach using video and multiplexing techniques.

A video and multiplexing system is described that provides a source of display in real-time, slow-motion, and stop-frame modes of ventricular activation. The displayed image, consisting of a matrix of 112 dots, is arranged to represent a polar projection of the ventricles. The dots brighten at the time of local cardiac activation, which is sensed by an electrode array monitoring the myocardium. Experiments in in situ canine hearts have provided detailed depictions at 8.3-ms intervals of the ventricular activation sequence during sinus and ventricularly paced rhythm. The origin of ventricular paced beats can be located with an accuracy of less than 5 mm. Coronary occlusion produces a defect in the displayed image that outlines the ischemic area and demonstrates regions of delayed conduction. This approach to ventricular mapping provides a detailed on-line display of activation with a recording capacity of 1 h. The system offers a practical, inexpensive alternative to computerized methods of investigating ventricular arrhythmias in both the experimental and intraoperative environment.

Animals↗
PubMed1999

Functional magnetic resonance imaging neuroactivation studies in normal subjects and subjects with the narcoleptic syndrome. Actions of modafinil.

Functional magnetic resonance imaging (fMRI) can be used to detect regional brain responses to changes in sensory stimuli. We have used fMRI to determine the amount of visual and auditory cortical activation in 12 normal subjects and 12 subjects with the narcoleptic syndrome, using a multiplexed visual and auditory stimulation paradigm. In both normal and narcoleptic subjects, mean cortical activation levels during the presentation of periodic visual and auditory stimulation showed no appreciable differences with either age or sex. Normal subjects showed higher levels of visual activation at 10:00 hours than 15:00 hours, with a reverse pattern in narcoleptic subjects (P = 0.007). The group differences in spatial extent of cortical activation between control and narcoleptic subjects were small and statistically insignificant. The alerting action, and imaging response, to a single oral dose of the sleep-preventing drug modafinil 400 mg were then determined and compared with placebo in both the 12 normal (8 given modafinil, 4 placebo) and 12 narcoleptic subjects (8 modafinil, 4 placebo). Modafinil caused an increase in self-reported levels of alertness in 7 of 8 narcoleptic subjects, but there was no significant difference between mean pretreatment and post-treatment activation levels as determined by fMRI for either normal or narcoleptic syndrome subjects given modafinil. However, in the modafinil-treated group of 8 normal and 8 narcoleptic subjects, there was a clock time independent correlation between the initial level of activation as determined by the pretreatment scan and the post-treatment change in activation (visual, P = 0.002; and auditory, P = 0.001). No correlation was observed in placebo-treated subjects (P = 0.99 and 0.77, respectively). Although limited by the small number of subjects, and the lack of an objective measure of alertness, the findings of this study suggest that low cortical activation levels in both normal and narcoleptic subjects are increased following the administration of modafinil. Functional magnetic resonance imaging may be a valuable addition to established studies of attention.

Acoustic Stimulation↗
PubMed2005

Ultrasound research scanner for real-time synthetic aperture data acquisition.

Conventional ultrasound systems acquire ultrasound data sequentially one image line at a time. The architecture of these systems is therefore also sequential in nature and processes most of the data in a sequential pipeline. This often makes it difficult to implement radically different imaging strategies on the platforms and makes the scanners less accessible for research purposes. A system designed for imaging research flexibility is the prime concern. The possibility of sending out arbitrary signals and the storage of data from all transducer elements for 5 to 10 seconds allows clinical evaluation of synthetic aperture and 3D imaging. This paper describes a real-time system specifically designed for research purposes. The system can acquire multichannel data in real-time from multi-element ultrasound transducers, and can perform some real-time processing on the acquired data. The system is capable of performing real-time beamforming for conventional imaging methods using linear, phased, and convex arrays. Image acquisition modes can be intermixed, and this makes it possible to perform initial trials in a clinical environment with new imaging modalities for synthetic aperture imaging, 2D and 3D B-mode, and velocity imaging using advanced coded emissions. The system can be used with 128-element transducers and can excite 128 transducer elements and receive and sample data from 64 channels simultaneously at 40 MHz with 12-bit precision. Two-to-one multiplexing in receive can be used to cover 128 receive channels. Data can be beamformed in real time using the system's 80 signal processing units, or it can be stored directly in RAM. The system has 16 Gbytes RAM and can, thus, store more than 3.4 seconds of multichannel data. It is fully software programmable and its signal processing units can also be reconfigured under software control. The control of the system is done over a 100-Mbits/s Ethernet using C and Matlab. Programs for doing, e.g., B-mode imaging can be written directly in Matlab and executed on the system over the net from any workstation running Matlab. The overall system concept is presented along with its implementation and examples of B-mode and in vivo synthetic aperture flow imaging.

Analog-Digital Conversion↗
PubMed2026

RNF43 Mutations Are Associated With the Classical Molecular Subtype, Vigorous Antitumor Immune Responses, and Prolonged Survival in Pancreatic Adenocarcinoma.

RNF43 mutations were correlated with microsatellite status in colorectal cancer and with fewer and later recurrences in pancreatic ductal adenocarcinoma (PDAC). Here, we undertake a detailed assessment of RNF43 mutations in PDAC. A total of 313 PDACs (308 microsatellite stable [MSS] and 5 microsatellite-instable [MSI] cases) underwent next-generation sequencing (Oncomine Tumor Mutation Load assay; Thermo Fisher). Spatial analyses (NanoString) classified PDACs according to their transcriptomic and proteomic immune signaling. Fluorescent imaging was used to define spatial compartments (tumor: pancytokeratin+/CD45- and leukocytes: pancytokeratin-/CD45+). Each of 20 PDACs with RNF43 mutations (RNF43mut) and without RNF43 mutations (RNF43wt) underwent multiplex immunofluorescence analysis to determine immune status. A total of 153 PDACs (22 RNF43mut and 131 RNF43wt cases) underwent bulk RNA sequencing to assign into molecular subtypes. Overall, 24 RNF43 mutations were identified (22 MSS PDACs and 2 MSI PDACs). The incidence of RNF43 mutations in MSS PDACs (7.1%) was consistent with The Cancer Genome Atlas (6.7%). However, RNF43 mutations were more frequent among MSI PDACs (40%). Additionally, RNF43mut had differential frequencies of other mutations (including Wnt pathway genes), higher tumor mutational burden values (5.5 mut/mb vs 1.67 mut/mb; P < .01), and significantly longer overall survival (47 vs 18 months; P < .0001) than RNF43wt. Moreover, RNF43mut exhibited significantly higher densities of CD8+ T lymphocytes, dendritic cells, and B lymphocytes (P < .001) and an upregulation of ITGAX, CD11c, CD8, and HLA-DR compared with RNF43wt. Patients with RNF43mut PDACs were more often of the classical molecular subtype (20/22, 90.9%). RNF43mut PDACs showed high tumor mutational burden values, suggesting increased neoantigen load coupled with an abundance of antigen-presenting immune cells and an upregulation of immune determinants promoting antigen presentation. All this contributes to stronger antitumor immune responses and improved clinical outcomes.

Humans↗
PubMed2006

Application of multiline two-photon microscopy to functional in vivo imaging.

High spatial resolution and low risks of photodamage make two-photon laser-scanning microscopy (TPLSM) the method of choice for biological imaging. However, the study of functional dynamics such as neuronal calcium regulation often also requires a high temporal resolution. Hitherto, acquisition speed is usually increased by line scanning, which restricts spatial resolution to structures along a single axis. To overcome this gap between high spatial and high temporal resolution we performed TPLSM with a beam multiplexer to generate multiple laser foci inside the sample. By detecting the fluorescence emitted from these laser foci with an electron-multiplying camera, it was possible to perform multiple simultaneous linescans. In addition to multiline scanning, the array of up to 64 laser beams could also be used in x-y scan mode to collect entire images at high frame rates. To evaluate the applicability of multiline TPLSM to functional in vivo imaging, calcium signals were monitored in visual motion-sensitive neurons in the brain of flies. The capacity of our method to simultaneously acquire signals at different cellular locations is exemplified by measurements at branched neurites and 'spine'-like structures. Calcium dynamics depended on branch size, but 'spines' did not systematically differ from their 'parent neurites'. The spatial resolution of our setup was critically evaluated by comparing it to confocal microscopy and the negative effect of scattering of emission light during image detection was assessed directly by running the setup in both imaging and point-scanning mode.

Animals↗
PubMed2004

Detection of pathogenic Vibrio spp. in shellfish by using multiplex PCR and DNA microarrays.

This study describes the development of a gene-specific DNA microarray coupled with multiplex PCR for the comprehensive detection of pathogenic vibrios that are natural inhabitants of warm coastal waters and shellfish. Multiplex PCR with vvh and viuB for Vibrio vulnificus, with ompU, toxR, tcpI, and hlyA for V. cholerae, and with tlh, tdh, trh, and open reading frame 8 for V. parahaemolyticus helped to ensure that total and pathogenic strains, including subtypes of the three Vibrio spp., could be detected and discriminated. For DNA microarrays, oligonucleotide probes for these targeted genes were deposited onto epoxysilane-derivatized, 12-well, Teflon-masked slides by using a MicroGrid II arrayer. Amplified PCR products were hybridized to arrays at 50 degrees C and detected by using tyramide signal amplification with Alexa Fluor 546 fluorescent dye. Slides were imaged by using an arrayWoRx scanner. The detection sensitivity for pure cultures without enrichment was 10(2) to 10(3) CFU/ml, and the specificity was 100%. However, 5 h of sample enrichment followed by DNA extraction with Instagene matrix and multiplex PCR with microarray hybridization resulted in the detection of 1 CFU in 1 g of oyster tissue homogenate. Thus, enrichment of the bacterial pathogens permitted higher sensitivity in compliance with the Interstate Shellfish Sanitation Conference guideline. Application of the DNA microarray methodology to natural oysters revealed the presence of V. vulnificus (100%) and V. parahaemolyticus (83%). However, V. cholerae was not detected in natural oysters. An assay involving a combination of multiplex PCR and DNA microarray hybridization would help to ensure rapid and accurate detection of pathogenic vibrios in shellfish, thereby improving the microbiological safety of shellfish for consumers.

Animals↗
PubMed1996

Multiplex messenger assay: simultaneous, quantitative measurement of expression of many genes in the context of T cell activation.

The hybridization signature approach, using colony filters and labeled complex probes, can provide high throughput measurement of gene activity. We describe here the implementation of this method to follow the expression levels of 47 genes in resting and activated T cells, as well as in epithelial cells. Using 4-fold spotting of colonies, imaging plate detection and various correction and normalization procedures, the technique is sensitive enough to quantify expression levels for sequences present at 0.005% abundance in the probe. Comparison with Northern blotting shows good consistency between the two methods. Upon activation of a T cell clone by an anti-CD3 antibody variations ranging from 2- to 20-fold are measured, some of which had not been reported previously. This 'multiplex messenger assay' method, performed using available commercial apparatus, can be used in many cases where simultaneous assessment of mRNA levels for many genes is of interest.

Animals↗
PubMed2026

Single-section multiplex spatial proteomics of immune microenvironments in kidney transplantation.

Characterizing kidney disease is challenged by marked cellular heterogeneity and limited tissue availability from renal biopsies. Conventional diagnostic workflows rely on multiple serial sections for parallel staining, increasing tissue consumption, sampling bias, and loss of spatial information, thereby constraining molecular characterization within intact tissue architecture. High-plex spatial proteomics may overcome these limitations by enabling comprehensive molecular profiling on a single section. Here, we present and evaluate a high-plex cyclic immunofluorescence imaging workflow (MACSima&#x2122;, Miltenyi Biotec) applied to kidney transplant biopsies, including BK virus nephropathy (BKVN) and focal segmental glomerulosclerosis (FSGS), to characterize spatial immune organization with a focus on complement system components. Feasibility and subcellular resolution were first assessed in a lupus nephritis section, demonstrating compatibility with diagnostic immune panels and preservation of tissue morphology. A 48-marker multiplex panel interrogating immunity, oxidative stress, senescence, and fibrosis was then applied to BKVN samples, including paired pre- and post-treatment biopsies, revealing distinct proteomic patterns and dynamic changes following therapy. In FSGS, a glomerulus-focused panel identified spatially resolved innate and adaptive immune signatures, including complement-related patterns supporting exploratory analysis of glomerular immune architecture. Structural, nuclear, membrane, and phosphorylated signaling markers enabled precise delineation of renal compartments and assessment of cellular states such as proliferation, DNA damage, and pathway activation. The workflow also supported detection of extracellular vesicles in cultured renal cells, highlighting its versatility. Overall, this approach provides a robust, tissue-sparing platform for integrated spatial and molecular profiling of renal biopsies, reducing sampling bias while enabling discovery-level phenotyping from a single section. This unified strategy is particularly suited to kidney transplantation, where diagnosis, therapeutic decision-making, and longitudinal monitoring are closely interconnected.

Kidney Transplantation↗