1. Articles in category: Developmental Biology

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    1. Visualizing flow in an intact CSF network using optical coherence tomography: implications for human congenital hydrocephalus

      Visualizing flow in an intact CSF network using optical coherence tomography: implications for human congenital hydrocephalus

      Cerebrospinal fluid (CSF) flow in the brain ventricles is critical for brain development. Altered CSF flow dynamics have been implicated in congenital hydrocephalus (CH) characterized by the potentially lethal expansion of cerebral ventricles if not treated. CH is the most common neurosurgical indication in children effecting 1 per 1000 infants. Current treatment modalities are limited to antiquated brain surgery techniques, mostly because of our poor understanding of the CH pathophysiology. We lack model systems where the interplay between ependymal cilia, embryonic CSF flow dynamics and brain development can be analyzed in depth. This is in part due to the poor ...

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      Mentions: Yale University
    2. Automated drosophila heartbeat counting based on image segmentation technique on optical coherence tomography

      Automated drosophila heartbeat counting based on image segmentation technique on optical coherence tomography

      Drosophila and human cardiac genes are very similar. Biological parametric studies on drosophila cardiac have improved our understanding of human cardiovascular disease. Drosophila cardiac consist of five circular chambers: a conical chamber (CC) and four ostia sections (O1–O4). Due to noise and grayscale discontinuity on optical coherence tomography (OCT) images, previous researches used manual counting or M-mode to analyze heartbeats, which are inefficient and time-consuming. An automated drosophila heartbeat counting algorithm based on the chamber segmentation is developed for OCT in this study. This algorithm has two parts: automated chamber segmentation and heartbeat counting. In addition, this study proposes ...

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    3. University of Houston Receives NIH Grant for Structural and Molecular Phenotyping of Embryonic Development Through Multi-Modal Optical Imaging

      University of Houston Receives NIH Grant for Structural and Molecular Phenotyping of Embryonic Development Through Multi-Modal Optical Imaging

      University of Houston Receives a 2019 NIH Grant for $676,224 for Structural and Molecular Phenotyping of Embryonic Development Through Multi-Modal Optical Imaging. The principal investigator is David Mayerich The program began in 2019 and ends in 2024. Below is a summary of the proposed work. The ability to correlate between large-scale developmental milestones and micro-scale cellular and protein- specific changes is a significant unmet need in the study of developmental biology. The overall objective of this work is to develop a multi-modality imaging platform that can provide time resolved three-dimensional images of tissue development, with high temporal and spatial ...

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    4. Micro-indentation and optical coherence tomography for the mechanical characterization of embryos: Experimental setup and measurements on fixed chicken embryos.

      Micro-indentation and optical coherence tomography for the mechanical characterization of embryos: Experimental setup and measurements on fixed chicken embryos.

      The investigation of the mechanical properties of embryos is expected to provide valuable information on the phenomenology of morphogenesis. It is thus believed that, by mapping the viscoelastic features of an embryo at different stages of growth, it may be possible to shed light on the role of mechanics in embryonic development. To contribute to this field, we present a new instrument that can determine spatiotemporal distributions of mechanical properties of embryos over a wide area and with unprecedented accuracy. The method relies on combining ferrule-top micro-indentation, which provides local measurements of viscoelasticity, with Optical Coherence Tomography, which can reveal ...

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    5. 4-D Computational Modeling of Cardiac Outflow Tract Hemodynamics over Looping Developmental Stages in Chicken Embryos

      4-D Computational Modeling of Cardiac Outflow Tract Hemodynamics over Looping Developmental Stages in Chicken Embryos

      Cardiogenesis is interdependent with blood flow within the embryonic system. Recently, a number of studies have begun to elucidate the effects of hemodynamic forces acting upon and within cells as the cardiovascular system begins to develop. Changes in flow are picked up by mechanosensors in endocardial cells exposed to wall shear stress (the tangential force exerted by blood flow) and by myocardial and mesenchymal cells exposed to cyclic strain (deformation). Mechanosensors stimulate a variety of mechanotransduction pathways which elicit functional cellular responses in order to coordinate the structural development of the heart and cardiovascular system. The looping stages of heart ...

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    6. Micro-indentation and optical coherence tomography for the mechanical characterization of embryos

      Micro-indentation and optical coherence tomography for the mechanical characterization of embryos

      The investigation of the mechanical properties of embryos is expected to provide valuable information on the phenomenology of morphogenesis. It is thus believed that, by mapping the viscoelastic features of an embryo at different stages of growth, it may be possible to shed light on the role of mechanics in embryonic development. To contribute to this field, we present a new instrument that can determine spatiotemporal distributions of mechanical properties of embryos over a wide area and with unprecedented accuracy. The method relies on combining ferrule-top micro-indentation, which provides local measurements of viscoelasticity, with Optical Coherence Tomography, which can reveal ...

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    7. In vivo monitoring and high-resolution characterizing of the prednisolone-induced osteoporotic process on adult zebrafish by optical coherence tomography

      In vivo monitoring and high-resolution characterizing of the prednisolone-induced osteoporotic process on adult zebrafish by optical coherence tomography

      Because of its similar genetic makeup with humans, zebrafish are an available and well-established osteoporosis model in vivo for anti-osteoporosis drug development as well as the drug safety-evaluation process. However, few optical imaging methods could effectively visualize the bone of adult zebrafish due to their limited penetration depth. In this paper, in vivo high-resolution and long-term characterization of a prednisolone-induced osteoporotic zebrafish model was achieved with spectral-domain optical coherence tomography (SD-OCT). The capability of three-dimensional SD-OCT imaging was also demonstrated in this study. With SD-OCT images, we could non-destructively monitor the deforming process of adult zebrafish skull from several directions ...

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    8. Baylor College of Medicine Receives NIH Grant for In Vivo Analysis of Mammalian Fertilization

      Baylor College of Medicine Receives NIH Grant for In Vivo Analysis of Mammalian Fertilization

      Baylor College of Medicine Receives a 2019 NIH Grant for $657,043 for In Vivo Analysis of Mammalian Fertilization. The principal investigator is Irina Larina. The program began in 2019 and ends in 2022. Below is a summary of the propose work. Estrous cycle, ovulation, fertilization, and pre-implantation pregnancy are fundamental reproductive processes of clinical importance. While research has shed light on the cellular and molecular mechanisms mediating these events, much of these data are derived from static histological analysis, low-resolution visualizations, and studies of invertebrate models (e.g. sea urchin). Therefore, any conclusions regarding mammalian fertilization, which takes place ...

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    9. University of Houston Receives NIH Grant for Optical Coherence Tomography to Study Effects of Poly-Drug Exposure of Fetal Brain Development

      University of Houston Receives NIH Grant for Optical Coherence Tomography to Study Effects of Poly-Drug Exposure of Fetal Brain Development

      University of Houston Receives 2019 NIH Grant for $345,824 for Optical Coherence Tomography to Study Effects of Poly-Drug Exposure of Fetal Brain Development. The principal investigator is Kirill Larin. The program began in 2016 and ends in 2020. Below is a summary of the proposed work. The overall objective of this study is to develop an optical coherence tomography (OCT) based high- resolution mouse embryonic brain imaging and analysis approach, and to use this method in correlation with molecular analysis to understand the interplay between ethanol (EtOH) and nicotine (NIC) effects on embryonic brain development. Maternal exposures to these ...

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    10. Ultrahigh Resolution Mouse Optical Coherence Tomography to Aid Intraocular Injection in Retinal Gene Therapy Research

      Ultrahigh Resolution Mouse Optical Coherence Tomography to Aid Intraocular Injection in Retinal Gene Therapy Research

      HR-SD-OCT is utilized to monitor the progression of photoreceptor degeneration in live mouse models, assess the delivery of therapeutic agents into the subretinal space, and to evaluate toxicity and efficacy in vivo. HR-SD-OCT uses near infrared light (800-880 nm) and has optics specifically designed for the unique optics of the mouse eye with sub-2-micron axial resolution. Transgenic mouse models of outer retinal (photoreceptor) degeneration and controls were imaged to assess the disease progression. Pulled glass microneedles were used to deliver sub retinal injections of adeno-associated virus (AAV) or nanoparticles (NP) via a trans-scleral and trans-choroidal approach. Careful positioning of the ...

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    11. Understanding congenital heart defects to prevent them

      Understanding congenital heart defects to prevent them

      To understand cardiovascular failures, the leading cause of birth defect-related deaths in infants, UH professor of biomedical engineering Kirill Larin is teaming up with Baylor College of Medicine professor of cellular and molecular physiology Irina Larina on a chicken and egg hunt. "When the heart develops, it becomes stiffer as required for ability to contract and pump blood," said Larin. "So the question is - does it become stiff because it's contracting, or is it stiff to begin with because it is genetically predefined?" Surprisingly, very little is known about an embryo's developing heart. "Defining how these mechanical factors ...

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    12. Understanding Congenital Heart Defects To Prevent Them

      Understanding Congenital Heart Defects To Prevent Them

      To understand cardiovascular failures, the leading cause of birth defect-related deaths in infants, UH professor of biomedical engineering Kirill Larin is teaming up with Baylor College of Medicine professor of cellular and molecular physiology Irina Larina on a chicken and egg hunt. “When the heart develops, it becomes stiffer as required for ability to contract and pump blood,” said Larin. “So the question is - does it become stiff because it’s contracting, or is it stiff to begin with because it is genetically predefined?” Surprisingly, very little is known about an embryo’s developing heart. “Defining how these mechanical factors ...

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    13. Monitoring Acute Stroke in Mouse Model Using Laser Speckle Imaging-Guided Visible-Light Optical Coherence Tomography

      Monitoring Acute Stroke in Mouse Model Using Laser Speckle Imaging-Guided Visible-Light Optical Coherence Tomography

      Objective: Monitoring hemodynamic and vascular changes in the acute stages of mouse stroke models is invaluable in studying ischemic stroke pathophysiology. However, there lacks a tool to simultaneously and dynamically investigate these changes. Methods: We integrated laser speckle imaging (LSI) and visible-light optical coherence tomography (Vis-OCT) to reveal dynamic vascular responses in acute stages in the distal middle cerebral artery occlusion (dMCAO) model in rodents. LSI provides full-field, real-time imaging to guide Vis-OCT imaging and monitor the dynamic cerebral blood flow (CBF). Vis-OCT offers depth-resolved angiography and oxygen saturation (sO 2 ) measurements. Results: Our results showed detailed CBF and vasculature ...

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    14. Imaging Melanin Distribution in the Zebrafish Retina Using Photothermal Optical Coherence Tomography

      Imaging Melanin Distribution in the Zebrafish Retina Using Photothermal Optical Coherence Tomography

      Purpose : To demonstrate and validate that photothermal optical coherence tomography (PT-OCT) can image melanin in the retinal pigment epithelium (RPE) and can observe light-driven melanosome translocation in the zebrafish retina. Methods : A commercial spectral domain OCT system was modified to perform both OCT and PT-OCT. Four adult tyrosinase-mosaic zebrafish with varying levels of melanin expression across their retinas were imaged, and the PT-OCT signal for pigmented and nonpigmented regions were compared. Wild-type dark-adapted ( n = 11 fish) and light-adapted ( n = 10 fish) zebrafish were also imaged with OCT and PT-OCT. Longitudinal reflectivity and absorption profiles were generated from B-scans to compare ...

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    15. Watching an embryo's neural tube close

      Watching an embryo's neural tube close

      In those precious weeks before a woman even realizes she's pregnant, an embryo will have already developed a neural tube, a hollow structure made of cells which will eventually become the brain and spinal cord. Now, with $3.2 million from the National Institutes of Health, UH professor of biomedical engineering Kirill Larin will tackle the evolutionary anomaly of why the neural tube closes in most embryos but remains open in others, leading to birth defects such as spina bifida and anencephaly. Neural Tube Defects (NTD) are the second most common structural birth defect in humans, affecting upwards of ...

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    16. Repeatability and Reproducibility of In Vivo Cone Density Measurements in the Adult Zebrafish Retina

      Repeatability and Reproducibility of In Vivo Cone Density Measurements in the Adult Zebrafish Retina

      Zebrafish ( Danio rerio ) are widely used as an experimental model for a wide range of retinal diseases. Previously, optical coherence tomography (OCT) was introduced for quantitative analysis of the zebrafish cone photoreceptor cell mosaic; however no data exists on the intersession reproducibility or intrasession repeatability of such measurements. We imaged 14 wild-type (WT) fish three times each, with 48 h between each time point. En face images of the UV cone mosaic were generated from the OCT volume scans at each time point. These images were then aligned and the overlapping area cropped for analysis. Using a semiautomated cone-counting algorithm ...

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    17. In Vivo Imaging of the Mouse Reproductive Organs, Embryo Transfer, and Oviduct Cilia Dynamics Using Optical Coherence Tomography

      In Vivo Imaging of the Mouse Reproductive Organs, Embryo Transfer, and Oviduct Cilia Dynamics Using Optical Coherence Tomography

      The oviduct (or fallopian tube) serves as the site where a number of major reproductive events occur for the start of a new life in mammals. Understanding the oviduct physiology is essential to uncover hidden mechanisms of the human reproduction and its disorders, yet the current analysis of the oviduct that is largely limited to in vitro imaging is a significant technical hurdle. To overcome this barrier, we have recently developed in vivo approaches based on optical coherence tomography for structural and functional imaging of the mouse oviduct. In this chapter, we describe the details of such live imaging methods ...

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    18. Using optical coherence tomography to detect disturbances in coronary microvascular in a model of fetal alcohol syndrome

      Using optical coherence tomography to detect disturbances in coronary microvascular in a model of fetal alcohol syndrome

      Congenital coronary anomalies can result in severe consequences such as arrhythmias and sudden death. However, the etiology of abnormal embryonic coronary microvasculature development is understudied. Using a novel contrast-agent-based optical coherence tomography (OCT) technique, scatter labeled imaging of microvasculature in excised tissue (SLIME), we compared diseased and normal embryonic quail coronary microvasculature in 3D. Congenital heart defects associated with fetal alcohol syndrome (FAS) were induced in a quail model by injecting 40 uL of 50% ethanol solution into eggs during gastrulation. These and saline-injected quail eggs were incubated until stage 36. SLIME contrast agent was perfused through the aortas of ...

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    19. Optical coherence computed tomography for quantitative 3D imaging of adult zebrafish

      Optical coherence computed tomography for quantitative 3D imaging of adult zebrafish

      Optical imaging in turbid media like biological tissue is limited by light scattering. We present optical coherence computed tomography (OCCT) as a novel optical imaging modality for ballistic 3D optical imaging of turbid media. In OCCT, coherence and confocal gated measurements from multiple lateral positions and angles are used to reconstruct quantitative 3D images of the optical attenuation and refractive index with tomographic reconstruction algorithms. OCCT allows for high resolution imaging in turbid media by strong suppression of scattered light using a combination of coherence and confocal gating. The time-of-flight information in the transmission measurements allows for quantitative reconstruction of ...

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    20. In vivo three-dimensional tracking of sperm behaviors in the mouse oviduct

      In vivo three-dimensional tracking of sperm behaviors in the mouse oviduct

      Mammalian sperm evolutionarily acquired complex mechanisms regulating their behaviors, which are thought to be critical in navigating through the female reproductive tract toward fertilization. However, all current knowledge of this process is largely extrapolated from in vitro and ex vivo studies, because in vivo analysis of sperm in their native fertilization environment has not been possible. Here we report a functional optical coherence tomography approach that allows, for the first time, in vivo three-dimensional (3D) tracking of sperm behaviors in the mouse oviduct. Motile sperm are identified with their intrinsic dynamic characteristics. Sperm trajectories are reconstructed in 3D with a ...

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    21. Functional optical coherence tomography for live dynamic analysis of mouse embryonic cardiogenesis

      Functional optical coherence tomography for live dynamic analysis of mouse embryonic cardiogenesis

      Blood flow, heart contraction, and tissue stiffness are important regulators of cardiac morphogenesis and function during embryonic development. Defining how these factors are integrated is critically important to advance prevention, diagnostics, and treatment of congenital heart defects. Mammalian embryonic development is taking place deep within the female body, which makes cardiodynamic imaging and analysis during early developmental stages in humans inaccessible. With thousands of mutant lines available and well-established genetic manipulation tools, mouse is a great model to understand how biomechanical factors are integrated with molecular pathways to regulate cardiac function and development. Dynamic imaging and quantitative analysis of the ...

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    22. Multimodality optical coherence tomography and fluorescence confocal scanning laser ophthalmoscopy in a zebrafish model of retinal vascular occlusion and remodeling

      Multimodality optical coherence tomography and fluorescence confocal scanning laser ophthalmoscopy in a zebrafish model of retinal vascular occlusion and remodeling

      Neovascularization in diabetic retinopathy (DR) and age-related macular degeneration (AMD) result in severe vision-loss and are two of the leading causes of blindness. The structural, metabolic, and vascular changes underlying retinal neovascularization are unknown and, thus, there is an unmet need to identify mechanisms of pathogenesis and novel anti-angiogenic therapies. Zebrafish is a robust ophthalmological model because its retina has comparable structure to the human retina and its fecundity and life-cycle enable development of mutant phenotypes of human pathologies. Here, we perform multimodal imaging with OCT and fluorescence confocal scanning laser ophthalmoscopy (cSLO) to identify changes in retinal structure and ...

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    23. Quantitative biometry of zebrafish retinal vasculature using optical coherence tomographic angiography

      Quantitative biometry of zebrafish retinal vasculature using optical coherence tomographic angiography

      The zebrafish is a robust model for studying human ophthalmic function and disease because of its fecundity, life-cycle, and similarities between its retinal structure and the human retina. Here, we demonstrate longitudinal in vivo imaging of retinal structure using optical coherence tomography (OCT) and noninvasive retinal vascular perfusion imaging using OCT angiography (OCT-A) in zebrafish. In addition, we present methods for retinal vascular segmentation and biometry to quantify vessel branch length, curvature, and angle. We further motivate retinal vascular biometry as a novel method for noninvasive zebrafish identification and demonstrated 99.9% accuracy for uniquely identifying eyes from a set ...

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    24. Quantification of the Effect of Toxicants on the Intracellular Kinetic Energy and Cross-Sectional Area of Mammary Epithelial Organoids by OCT Fluctuation Spectroscopy

      Quantification of the Effect of Toxicants on the Intracellular Kinetic Energy and Cross-Sectional Area of Mammary Epithelial Organoids by OCT Fluctuation Spectroscopy

      The ability to assess toxicant exposures of 3D in vitro mammary models that recapitulate the tissue microenvironment can aid in our understanding of environmental exposure risk over time. Longitudinal studies of 3D model systems, however, are cumbersome and suffer from a lack of high-throughput toxicological assays. In this study, we establish a noninvasive and label-free optical coherence tomography (OCT)-based imaging platform for tracking exposure-response relationships in 3D human mammary epithelial organoid models. The OCT-based assay includes metrics that quantify organoid intracellular kinetic energy and cross-sectional area (CSA). We compare the results to those obtained using the 3-(4,5-dimethylthiazol-2-yl ...

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