1. Articles from Mustafa K. Khokha

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    1. Visualization and quantification of injury to the ciliated epithelium using quantitative flow imaging and speckle variance optical coherence tomography

      Visualization and quantification of injury to the ciliated epithelium using quantitative flow imaging and speckle variance optical coherence tomography

      Mucociliary flow is an important defense mechanism in the lung to remove inhaled pathogens and pollutants. Disruption of ciliary flow can lead to respiratory infections. Multiple factors, from drugs to disease can cause an alteration in ciliary flow. However, less attention has been given to injury of the ciliated epithelium. In this study, we show how optical coherence tomography (OCT) can be used to investigate injury to the ciliated epithelium in a multi-contrast setting. We used particle tracking velocimetry (PTV-OCT) to investigate the cilia-driven flow field and 3D speckle variance imaging to investigate size and extent of injury caused to ...

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    2. Analysis of Craniocardiac Malformations in Xenopus using Optical Coherence Tomography : Scientific Reports

      Analysis of Craniocardiac Malformations in Xenopus using Optical Coherence Tomography : Scientific Reports

      Birth defects affect 3% of children in the United States. Among the birth defects, congenital heart disease and craniofacial malformations are major causes of mortality and morbidity. Unfortunately, the genetic mechanisms underlying craniocardiac malformations remain largely uncharacterized. To address this, human genomic studies are identifying sequence variations in patients, resulting in numerous candidate genes. However, the molecular mechanisms of pathogenesis for most candidate genes are unknown. Therefore, there is a need for functional analyses in rapid and efficient animal models of human disease. Here, we coupled the frog Xenopus tropicalis with Optical Coherence Tomography (OCT) to create a fast and ...

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    3. Particle streak velocimetry-optical coherence tomography: a novel method for multidimensional imaging of microscale fluid flows

      Particle streak velocimetry-optical coherence tomography: a novel method for multidimensional imaging of microscale fluid flows

      We present a new OCT method for flow speed quantification and directional velocimetry: particle streak velocimetry-OCT (PSV-OCT). PSV-OCT generates two-dimensional, 2.5-vector component ( v x ,| v y |, v z ) maps of microscale flow velocity fields. Knowledge of 2.5-vector components also enables the estimation of total flow speed. The enabling insight behind PSV-OCT is that tracer particles in sparsely-seeded fluid flow trace out streaks in ( x,z,t )-space. The streak orientations in x-t and z-t yield v x and v z , respectively. The in-plane ( x-z plane) residence time yields the out-of-plane speed | v y |. Vector component values are generated ...

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    4. Three-dimensional, three-vector-component velocimetry of cilia-driven fluid flow using correlation-based approaches in optical coherence tomography

      Three-dimensional, three-vector-component velocimetry of cilia-driven fluid flow using correlation-based approaches in optical coherence tomography

      Microscale quantification of cilia-driven fluid flow is an emerging area in medical physiology, including pulmonary and central nervous system physiology. Cilia-driven fluid flow is most completely described by a three-dimensional, three-component (3D3C) vector field. Here, we generate 3D3C velocimetry measurements by synthesizing higher dimensional data from lower dimensional measurements obtained using two separate optical coherence tomography (OCT)-based approaches: digital particle image velocimetry (DPIV) and dynamic light scattering (DLS)-OCT. Building on previous work, we first demonstrate directional DLS-OCT for 1D2C velocimetry measurements in the sub-1 mm/s regime (sub-2.5 inch/minute regime) of cilia-driven fluid flow in Xenopus ...

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    5. Quantitative optical coherence tomography imaging of intermediate flow defect phenotypes in ciliary physiology and pathophysiology

      Quantitative optical coherence tomography imaging of intermediate flow defect phenotypes in ciliary physiology and pathophysiology

      Cilia-driven fluid flow is a critical yet poorly understood aspect of pulmonary physiology. Here, we demonstrate that optical coherence tomography-based particle tracking velocimetry can be used to quantify subtle variability in cilia-driven flow performance in Xenopus , an important animal model of ciliary biology. Changes in flow performance were quantified in the setting of normal development, as well as in response to three types of perturbations: mechanical (increased fluid viscosity), pharmacological (disrupted serotonin signaling), and genetic (diminished ciliary motor protein expression). Of note, we demonstrate decreased flow secondary to gene knockdown of kif3a , a protein involved in ciliogenesis, as well as ...

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    6. Microfluidic Phenotyping of Cilia-Driven Mixing for the Assessment of Respiratory Diseases

      Microfluidic Phenotyping of Cilia-Driven Mixing for the Assessment of Respiratory Diseases

      The function of ciliated surfaces to clear mucus from the respiratory system is important for many respiratory diseases and, therefore, has a high impact on public health. In this work, we present a quantitative method to evaluate mixing efficiency of cilia-driven microfluidic flow based on front line deformation as an integrated measurement of cilia function. So far, mixing efficiency has been used mainly for analyzing artificial cilia. Most of this work, however, was either bound to specific imaging modalities or done on simulated data. In this simulations, mixing efficiency has been quantified as the change in length of a virtual ...

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    7. Feature Of The Week 2/12/12: Researchers at Yale University use OCT to Characterize Microfluidic Ciliary Induced Fluid Flow

      Feature Of The Week 2/12/12: Researchers at Yale University use OCT to Characterize Microfluidic Ciliary Induced Fluid Flow

      Recently researchers at Yale University demonstrated a very novel application of optical coherence tomography using a Thorlabs OCT system.  The research involved characterizing microfluidic flow of fluid driven by cilia.  Below is a summary of this interesting novel application of OCT.Motile cilia are fingerlike projections from different epithelial surfaces that move in a periodic manner to generate directional fluid flow. For example, respiratory cilia generate a microfluidic-scale flow that moves pathogen and allergen-containing mucus out of the lungs. Defects in motile cilia lead to recurrent respiratory infections. Despite the importance of cilia in rare disease such as primary ciliary ...

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    8. Microfluidic characterization of cilia-driven fluid flow using optical coherence tomography-based particle tracking velocimetry

      Microfluidic characterization of cilia-driven fluid flow using optical coherence tomography-based particle tracking velocimetry
      Motile cilia are cellular organelles that generate directional fluid flow across various epithelial surfaces including the embryonic node and respiratory mucosa. The proper functioning of cilia is necessary for normal embryo development and, for the respiratory system, the clearance of mucus and potentially harmful particulate matter. Here we show that optical coherence tomography (OCT) is well-suited for quantitatively characterizing the microfluidic-scale flow generated by motile cilia. Our imaging focuses on the ciliated epithelium of Xenopus tropicalis embryos, a genetically manipulable and experimentally tractable animal model of human disease. We show qualitative flow profile characterization using OCT-based particle pathline imaging. We ...
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    1-8 of 8
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    1. (8 articles) Yale University
    2. (8 articles) Michael A. Choma
    3. (2 articles) RWTH Aachen University
    4. (1 articles) Drexel University
    5. (1 articles) Thorlabs
    6. (1 articles) Thorlabs OCT Imaging Systems
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    Microfluidic characterization of cilia-driven fluid flow using optical coherence tomography-based particle tracking velocimetry Feature Of The Week 2/12/12: Researchers at Yale University use OCT to Characterize Microfluidic Ciliary Induced Fluid Flow Microfluidic Phenotyping of Cilia-Driven Mixing for the Assessment of Respiratory Diseases Quantitative optical coherence tomography imaging of intermediate flow defect phenotypes in ciliary physiology and pathophysiology Three-dimensional, three-vector-component velocimetry of cilia-driven fluid flow using correlation-based approaches in optical coherence tomography Particle streak velocimetry-optical coherence tomography: a novel method for multidimensional imaging of microscale fluid flows Analysis of Craniocardiac Malformations in Xenopus using Optical Coherence Tomography : Scientific Reports Visualization and quantification of injury to the ciliated epithelium using quantitative flow imaging and speckle variance optical coherence tomography Role of Intravascular Imaging in Primary PCI (Book Chapter) Clinical and OCT Findings in a Case of a Presumed Perfluorooctane Retinal Acute Toxicity Semi-manual Vessel Density Analysis on Optical Coherence Tomography Angiography Images of Healthy Adults OCT vs. Angiography to Guide PCI