scholarly journals High temporal resolution in vivo blood oximetry via projection-basedT2measurement

2012 ◽  
Vol 70 (3) ◽  
pp. 785-790 ◽  
Author(s):  
Varsha Jain ◽  
Jeremy Magland ◽  
Michael Langham ◽  
Felix W. Wehrli
Keyword(s):  
Temporal Resolution ◽  
High Temporal Resolution

scholarly journals Multimodal in vivo recording using transparent graphene microelectrodes illuminates spatiotemporal seizure dynamics at the microscale

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Nicolette Driscoll ◽  
Richard E. Rosch ◽  
Brendan B. Murphy ◽  
Arian Ashourvan ◽  
Ramya Vishnubhotla ◽  
...  
Keyword(s):  
Temporal Resolution ◽  
Spatial Scales ◽  
Epileptic Seizures ◽  
Therapeutic Interventions ◽  
State Transitions ◽  
Integrated Analysis ◽  
High Temporal Resolution ◽  
Seizure Onset ◽  
Acute Seizures

AbstractNeurological disorders such as epilepsy arise from disrupted brain networks. Our capacity to treat these disorders is limited by our inability to map these networks at sufficient temporal and spatial scales to target interventions. Current best techniques either sample broad areas at low temporal resolution (e.g. calcium imaging) or record from discrete regions at high temporal resolution (e.g. electrophysiology). This limitation hampers our ability to understand and intervene in aberrations of network dynamics. Here we present a technique to map the onset and spatiotemporal spread of acute epileptic seizures in vivo by simultaneously recording high bandwidth microelectrocorticography and calcium fluorescence using transparent graphene microelectrode arrays. We integrate dynamic data features from both modalities using non-negative matrix factorization to identify sequential spatiotemporal patterns of seizure onset and evolution, revealing how the temporal progression of ictal electrophysiology is linked to the spatial evolution of the recruited seizure core. This integrated analysis of multimodal data reveals otherwise hidden state transitions in the spatial and temporal progression of acute seizures. The techniques demonstrated here may enable future targeted therapeutic interventions and novel spatially embedded models of local circuit dynamics during seizure onset and evolution.

scholarly journals In vivo magnetic particle imaging: angiography of inferior vena cava and aorta in rats using newly developed multicore particles

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Azadeh Mohtashamdolatshahi ◽  
Harald Kratz ◽  
Olaf Kosch ◽  
Ralf Hauptmann ◽  
Nicola Stolzenburg ◽  
...  
Keyword(s):  
Image Quality ◽  
Inferior Vena Cava ◽  
Temporal Resolution ◽  
Magnetic Particle ◽  
Inferior Vena ◽  
Vena Cava ◽  
High Temporal Resolution ◽  
Magnetic Particle Imaging ◽  
Particle Imaging

Abstract Magnetic Particle Imaging (MPI) is a new imaging modality, which maps the distribution of magnetic nanoparticles (MNP) in 3D with high temporal resolution. It thus may be suited for cardiovascular imaging. Its sensitivity and spatial resolution critically depend on the magnetic properties of MNP. Therefore, we used novel multicore nanoparticles (MCP 3) for in-vivo MPI in rats and analyzed dose requirements, sensitivity and detail resolution. 8 rats were examined using a preclinical MPI scanner (Bruker Biospin GmbH, Germany) equipped with a separate receive coil. MCP 3 and Resovist were administered intravenously (i.v.) into the rats’ tail veins at doses of 0.1, 0.05 and 0.025 mmol Fe/kg followed by serial MPI acquisition with a temporal resolution of 46 volumes per second. Based on a qualitative visual scoring system MCP 3–MPI images showed a significantly (P ≤ 0.05) higher image quality than Resovist-MPI images. Morphological features such as vessel lumen diameters (DL) of the inferior vena cava (IVC) and abdominal aorta (AA) could be assessed along a 2-cm segment in mesenteric area only after administration of MCP 3 at dosages of 0.1, 0.05 mmol Fe/kg. The mean DL ± SD estimated was 2.7 ± 0.6 mm for IVC and 2.4 ± 0.7 mm for AA. Evaluation of DL of the IVC and AA was not possible in Resovist-MPI images. Our results show, that MCP 3 provide better image quality at a lower dosage than Resovist. MCP 3-MPI with a clinically acceptable dose of 0.05 mmol Fe/kg increased the visibility of vessel lumens compared to Resovist-based MPI towards possible detection of vascular abnormalities such as stenosis or aneurysms, in vivo.

scholarly journals Fast in vivo detection of myocardial norepinephrine levels in the beating porcine heart

2020 ◽  
Vol 318 (5) ◽  
pp. H1091-H1099 ◽  
Author(s):  
Shyue-An Chan ◽  
Marmar Vaseghi ◽  
Nicholas Kluge ◽  
Kalyanam Shivkumar ◽  
Jeffrey L. Ardell ◽  
...  
Keyword(s):  
Cardiac Function ◽  
Temporal Resolution ◽  
High Performance ◽  
Cardiac Tissue ◽  
Enzyme Linked Immunosorbent Assay ◽  
High Temporal Resolution ◽  
Sample Collection ◽  
Significant Information ◽  
Porcine Heart

The sympathetic nervous system modulates cardiac function by controlling key parameters such as chronotropy and inotropy. Sympathetic control of ventricular function occurs through extrinsic innervation arising from the stellate ganglia and thoracic sympathetic chain. In the healthy heart, sympathetic release of norepinephrine (NE) results in positive modulation of chronotropy, inotropy, and dromotropy, significantly increasing cardiac output. However, in the setting of myocardial infarction or injury, sympathetic activation persists, contributing to heart failure and increasing the risk of arrhythmias, including sudden cardiac death. Methodologies for detection of norepinephrine in cardiac tissue are limited. Present techniques rely on microdialysis for analysis by high-performance liquid chromatography coupled to electrochemical detection (HPLC-ED), radioimmunoassay, or other immunoassays, such as enzyme-linked immunosorbent assay (ELISA). Although significant information about the release and action of norepinephrine has been obtained with these methodologies, they are limited in temporal resolution, require large sample volumes, and provide results with a significant delay after sample collection (hours to weeks). In this study, we report a novel approach for measurement of interstitial cardiac norepinephrine, using minimally invasive, electrode-based, fast-scanning cyclic voltammetry (FSCV) applied in a beating porcine heart. The first multispatial and high temporal resolution, multichannel measurements of NE release in vivo are provided. Our data demonstrate rapid changes in interstitial NE profiles with regional differences in response to coronary ischemia, sympathetic nerve stimulation, and alterations in preload/afterload. NEW & NOTEWORTHY Pharmacological, electrical, or surgical regulation of sympathetic neuronal control can be used to modulate cardiac function and treat arrhythmias. However, present methods for monitoring sympathetic release of norepinephrine in the heart are limited in spatial and temporal resolution. Here, we provide for the first time a methodology and demonstration of practice and rapid measures of individualized regional autonomic neurotransmitter levels in a beating heart. We show dynamic, spatially resolved release profiles under normal and pathological conditions.

scholarly journals In vivo volumetric imaging of calcium and glutamate activity at synapses with high spatiotemporal resolution

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Wei Chen ◽  
Ryan G. Natan ◽  
Yuhan Yang ◽  
Shih-Wei Chou ◽  
Qinrong Zhang ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Temporal Resolution ◽  
Simultaneous Recording ◽  
High Temporal Resolution ◽  
Spatiotemporal Resolution ◽  
Volumetric Imaging ◽  
High Spatiotemporal Resolution ◽  
Mouse Cortex ◽  
Two Photon Fluorescence

AbstractStudying neuronal activity at synapses requires high spatiotemporal resolution. For high spatial resolution in vivo imaging at depth, adaptive optics (AO) is required to correct sample-induced aberrations. To improve temporal resolution, Bessel focus has been combined with two-photon fluorescence microscopy (2PFM) for fast volumetric imaging at subcellular lateral resolution. To achieve both high-spatial and high-temporal resolution at depth, we develop an efficient AO method that corrects the distorted wavefront of Bessel focus at the objective focal plane and recovers diffraction-limited imaging performance. Applying AO Bessel focus scanning 2PFM to volumetric imaging of zebrafish larval and mouse brains down to 500 µm depth, we demonstrate substantial improvements in the sensitivity and resolution of structural and functional measurements of synapses in vivo. This enables volumetric measurements of synaptic calcium and glutamate activity at high accuracy, including the simultaneous recording of glutamate activity of apical and basal dendritic spines in the mouse cortex.

scholarly journals Continuous detection of glucose and insulin in live animals

2020 ◽  
Author(s):  
Mahla Poudineh ◽  
Caitlin L. Maikawa ◽  
Eric Yue Ma ◽  
Jing Pan ◽  
Dan Mamerow ◽  
...  
Keyword(s):  
Real Time ◽  
Temporal Resolution ◽  
Simultaneous Detection ◽  
Diabetic Rats ◽  
High Temporal Resolution ◽  
Pharmacokinetics And Pharmacodynamics ◽  
Affinity Reagents ◽  
Versatile Tool ◽  
Multiple Analytes

AbstractReal-time biosensors that can continuously measure circulating biomolecules in vivo would provide valuable insights into a patients’ health status and their response to therapeutics even when there is considerable variability in pharmacokinetics and pharmacodynamics across patient populations. Unfortunately, current real-time biosensors are limited to a handful of analytes (e.g. glucose and blood oxygen) and are limited in sensitivity (high nanomolar). In this work, we describe a general approach for continuously and simultaneously measuring multiple analytes with picomolar sensitivity and sub-second temporal resolution. As exemplars, we report the simultaneous detection of glucose and insulin at picomolar concentrations in live diabetic rats. Using our system, we demonstrate the capacity to resolve inter-individual differences in the pharmacokinetic responses to insulin and discriminate profiles from different insulin formulations at a high temporal resolution. Critically, our approach is general and could be readily modified to continuously and simultaneously measure other circulating analytes in vivo by swapping the affinity reagents, thus making it a versatile tool for biomedical research.

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