1. Articles in category: Developmental Biology

    1-24 of 166 1 2 3 4 5 6 7 »
    1. Swept source optical coherence tomography Gabor fusion splicing technique for microscopy of thick samples using a deformable mirror

      Swept source optical coherence tomography Gabor fusion splicing technique for microscopy of thick samples using a deformable mirror

      We present a swept source optical coherence tomography (OCT) system at 1060 nm equipped with a wavefront sensor at 830 nm and a deformable mirror in a closed-loop adaptive optics (AO) system. Due to the AO correction, the confocal profile of the interface optics becomes narrower than the OCT axial range, restricting the part of the B-scan (cross section) with good contrast. By actuating on the deformable mirror, the depth of the focus is changed and the system is used to demonstrate Gabor filtering in order to produce B-scan OCT images with enhanced sensitivity throughout the axial range from a ...

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    2. Optical coherence tomography guided microinjections in live mouse embryos: high-resolution targeted manipulation for mouse embryonic research

      Optical coherence tomography guided microinjections in live mouse embryos: high-resolution targeted manipulation for mouse embryonic research

      The ability to conduct highly localized delivery of contrast agents, viral vectors, therapeutic or pharmacological agents, and signaling molecules or dyes to live mammalian embryos is greatly desired to enable a variety of studies in the field of developmental biology, such as investigating the molecular regulation of cardiovascular morphogenesis. To meet such a demand, we introduce, for the first time, the concept of employing optical coherence tomography (OCT)-guide microinjections in live mouse embryos, which provides precisely targeted manipulation with spatial resolution at the micrometer scale. The feasibility demonstration is performed with experimental studies on cultured live mouse embryos at ...

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    3. Developmental and morphological studies in Japanese medaka with ultra-high resolution optical coherence tomography

      Developmental and morphological studies in Japanese medaka with ultra-high resolution optical coherence tomography

      We propose ultra-high resolution optical coherence tomography to study the morphological development of internal organs in medaka fish in the post-embryonic stages at micrometer resolution. Different stages of Japanese medaka were imaged after hatching in vivo with an axial resolution of 2.8 µm in tissue. Various morphological structures and organs identified in the OCT images were then compared with the histology. Due to the medaka’s close resemblance to vertebrates, including humans, these morphological features play an important role in morphogenesis and can be used to study diseases that also occur in humans.

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      Mentions: Barry Cense
    4. Using optical coherence tomography to rapidly phenotype and quantify congenital heart defects associated with prenatal alcohol exposure

      Using optical coherence tomography to rapidly phenotype and quantify congenital heart defects associated with prenatal alcohol exposure

      Background : The most commonly used method to analyze congenital heart defects involves serial sectioning and histology. However, this is often a time-consuming process where the quantification of cardiac defects can be difficult due to problems with accurate section registration. Here we demonstrate the advantages of using optical coherence tomography, a comparatively new and rising technology, to phenotype avian embryo hearts in a model of Fetal Alcohol Syndrome where a binge-like quantity of alcohol/ethanol was introduced at gastrulation. Results : The rapid, consistent imaging protocols allowed for the immediate identification of cardiac anomalies, including ventricular septal defects and misaligned/missing vessels ...

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    5. Baylor College of Medicine Receives a NIH Grant for Studying Biomechanics of Early Mammalian Cardiogenesis.

      Baylor College of Medicine Receives a  NIH Grant for Studying Biomechanics of Early Mammalian Cardiogenesis.

      Baylor College of Medicine Receives a 2014 NIH Grant for $33,801 for Studying Biomechanics of Early Mammalian Cardiogenesis. The principal investgator is Irina Larina. The program begain in 2013 and ends in 2018. Below is a summary of the proposed work.

      Congenital heart defects are among the most common birth defects and the leading cause of death in children born with congenital defects. Understanding how the early embryonic heart functions and what regulatory mechanisms are involved in early cardiogenesis is highly important for advancement of heart defects research. Biomechanical stimuli, including blood flow and heart contraction, are important regulators ...

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    6. Imaging of cardiovascular development in Mammalian embryos using optical coherence tomography (Book Chapter)

      Imaging of cardiovascular development in Mammalian embryos using optical coherence tomography (Book Chapter)

      The cardiovascular system is the first functional organ system to develop within the mammalian embryo. During the early stages of cardiovascular development, the heart and blood vessels undergo rapid growth and remodeling required for embryo viability, proper morphogenesis, and the function of all organ systems. Live imaging of these dynamic events in early mouse embryos is critical to understanding when and how these morphological changes occur during normal development and how mutations and pharmacological agents affect cardiovascular structure and function in vivo. The use of optical coherence tomography (OCT) allows for rapid, three-dimensional structural and functional imaging of mouse embryos ...

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    7. Morphological phenotyping of mouse hearts using optical coherence tomography

      Morphological phenotyping of mouse hearts using optical coherence tomography

      Transgenic mouse models have been instrumental in the elucidation of the molecular mechanisms behind many genetically based cardiovascular diseases such as Marfan syndrome (MFS). However, the characterization of their cardiac morphology has been hampered by the small size of the mouse heart. In this report, we adapted optical coherence tomography (OCT) for imaging fixed adult mouse hearts, and applied tools from computational anatomy to perform morphometric analyses. The hearts were first optically cleared and imaged from multiple perspectives. The acquired volumes were then corrected for refractive distortions, and registered and stitched together to form a single, high-resolution OCT volume of ...

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    8. Ex vivo 4D visualization of aortic valve dynamics in a murine model with optical coherence tomography

      Ex vivo 4D visualization of aortic valve dynamics in a murine model with optical coherence tomography

      The heart and its mechanical components, especially the heart valves and leaflets, are under enormous strain and undergo fatigue, which impinge upon cardiac output. The knowledge about changes of the dynamic behavior and the possibility of early stage diagnosis could lead to the development of new treatment strategies. Animal models are suited for the development and evaluation of new experimental approaches and therefor innovative imaging techniques are necessary. In this study, we present the time resolved visualization of healthy and calcified aortic valves in an ex vivo artificially stimulated heart model with 4D optical coherence tomography and high-speed video microscopy.

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    9. Rapid, Accurate, and Non-Invasive Measurement of Zebrafish Axial Length and Other Eye Dimensions Using SD-OCT Allows Longitudinal Analysis of Myopia and Emmetropization

      Rapid, Accurate, and Non-Invasive Measurement of Zebrafish Axial Length and Other Eye Dimensions Using SD-OCT Allows Longitudinal Analysis of Myopia and Emmetropization

      Refractive errors in vision can be caused by aberrant axial length of the eye, irregular corneal shape, or lens abnormalities. Causes of eye length overgrowth include multiple genetic loci, and visual parameters. We evaluate zebrafish as a potential animal model for studies of the genetic, cellular, and signaling basis of emmetropization and myopia. Axial length and other eye dimensions of zebrafish were measured using spectral domain-optical coherence tomography (SD-OCT). We used ocular lens and body metrics to normalize and compare eye size and relative refractive error (difference between observed retinal radial length and controls) in wild-type and lrp2 zebrafish. Zebrafish ...

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    10. Capturing structure and function in an embryonic heart with biophotonic tools

      Capturing structure and function in an embryonic heart with biophotonic tools

      Disturbed cardiac function at an early stage of development has been shown to correlate with cellular/molecular, structural as well as functional cardiac anomalies at later stages culminating in the congenital heart defects (CHDs) that present at birth. While our knowledge of cellular and molecular steps in cardiac development is growing rapidly, our understanding of the role of cardiovascular function in the embryo is still in an early phase. One reason for the scanty information in this area is that the tools to study early cardiac function are limited. Recently developed and adapted biophotonic tools may overcome some of the ...

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    11. Hemodynamic Flow Visualization of Early Embryonic Great Vessels Using μPIV

      Hemodynamic Flow Visualization of Early Embryonic Great Vessels Using μPIV

      Microparticle image velocimetry (μPIV) is an evolving quantitative methodology to closely and accurately monitor the cardiac flow dynamics and mechanotransduction during vascular morphogenesis. While PIV technique has a long history, contemporary developments in advanced microscopy have significantly expanded its power. This chapter includes three new methods for μPIV acquisition in selected embryonic structures achieved through advanced optical imaging: (1) high-speed confocal scanning of transgenic zebrafish embryos, where the transgenic erythrocytes act as the tracing particles; (2) microinjection of artificial seeding particles in chick embryos visualized with stereomicroscopy; and (3) real-time, time-resolved optical coherence tomography acquisition of vitelline vessel flow profiles ...

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    12. Retinal Regeneration Following OCT-guided Laser Injury in Zebrafish

      Retinal Regeneration Following OCT-guided Laser Injury in Zebrafish

      Purpose: Establish a focal injury/regeneration model in zebrafish using laser photocoagulation guided by optical coherence tomography (OCT). Methods: Adult zebrafish were imaged by OCT and confocal scanning laser ophthalmoscopy (cSLO) in room air through a contact lens. Using a beam combiner, 532nm laser photocoagulation was applied using the OCT C-scan image for targeting. Laser spots of 42-47mW were delivered to the retina. At multiple intervals post-injury, fish were imaged using both OCT and cSLO to follow the progression of each lesion. Histologic sections and TUNEL staining were performed to monitor the injury response. Results: Round lesions (26057 ± 621μm2 ...

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    13. Blood flow dynamics reflect degree of outflow tract banding in Hamburger-Hamilton stage 18 chicken embryos

      Blood flow dynamics reflect degree of outflow tract banding in Hamburger-Hamilton stage 18 chicken embryos

      Altered blood flow during embryonic development has been shown to cause cardiac defects; however, the mechanisms by which the resulting haemodynamic forces trigger heart malformation are unclear. This study used heart outflow tract banding to alter normal haemodynamics in a chick embryo model at HH18 and characterized the immediate blood flow response versus the degree of band tightness. Optical coherence tomography was used to acquire two-dimensional longitudinal structure and Doppler velocity images from control ( n = 16) and banded ( n = 25, 6–64% measured band tightness) embryos, from which structural and velocity data were extracted to estimate haemodynamic measures. Peak blood ...

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    14. Dual modality optical coherence and whole-body photoacoustic tomography imaging of chick embryos in multiple development stages

      Dual modality optical coherence and whole-body photoacoustic tomography imaging of chick embryos in multiple development stages

      Chick embryos are an important animal model for biomedical studies. The visualization of chick embryos, however, is limited mostly to postmortem sectional imaging methods. In this work, we present a dual modality optical imaging system that combines swept-source optical coherence tomography and whole-body photoacoustic tomography, and apply it to image chick embryos at three different development stages. The explanted chick embryos were imaged in toto with complementary contrast from both optical scattering and optical absorption. The results serve as a prelude to the use of the dual modality system in longitudinal whole-body monitoring of chick embryos in ovo .

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    15. Gated optical coherence tomography (OCT)

      Gated optical coherence tomography (OCT)

      Systems, methods, and other embodiments associated with gated optical coherence tomography (OCT) are described. One example method includes generating an image control signal to control an OCT apparatus to acquire an image of an embryonic heart at a specified point in time during a cardiac cycle of the embryonic heart. The method may also include controlling the OCT apparatus to acquire the image based on the image control signal. In different examples, the image may be acquired in vivo or from an excised heart that is paced. The OCT apparatus and the embryonic heart may be housed in an environmental ...

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    16. Optical Coherence Tomography: Age estimation of Calliphora vicina pupae in vivo?

      Optical Coherence Tomography: Age estimation of Calliphora vicina pupae in vivo?

      Necrophagous blowfly pupae are valuable contributors to the estimation of post-mortem interval, should an accurate age estimate be obtained. At present, this is reliant on a combination of rearing and destructive methods conducted on preserved samples, including morphological observation and gene expression analyses. This study demonstrates the use of optical coherence tomography (OCT) as a tool for in vivo morphological observation and pupal age estimation. Using a Michelson OCT microscope, alive and preserved four and ten-day old Calliphora vicina pupae were scanned in different orientations. Two and three-dimensional images were created. Morphological characteristics such as the brain, mouthparts and legs ...

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    17. Zebrafish as a Model to Study Emmetropization, Refractive Error, and Retinal Substructure using Spectral Domain-Optical Coherence Tomography

      Zebrafish as a Model to Study Emmetropization, Refractive Error, and Retinal Substructure using Spectral Domain-Optical Coherence Tomography

      Purpose : Spectral-domain optical coherence tomography (SD-OCT) accurately measures the anatomy and dimensions of the eye in vivo . Here, we characterize emmetropization of wild-type zebrafish, myopia onset in bugeye/lrp2 mutants, and visualize the highly ordered cone photoreceptor mosaic by SD-OCT. We combine high resolution visualization with an animal model amenable to genetic manipulation that can be used to study candidate genes for refractive error and other ocular diseases. Methods : Eye axial length, focal length and lens diameter were measured in wild-type and bugeye/lrp2 mutant zebrafish throughout their lifespan using a Bioptigen SD-OCT system. Cone photoreceptor mosaics were visualized using ...

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    18. Baylor College of Medicine Receives NIH Grant for Studying Biomechanics of Early Mammalian Cardiogenesis

      Baylor College of Medicine Receives NIH Grant for Studying Biomechanics of Early Mammalian Cardiogenesis

      Baylor College of Medicine Received a 2014 NIH Grant for $378,647 for Biomechanics of Early Mammalian Cardiogenesis. The principal investigator is Irina Larina. The program began in 2013 and ends in 2018. Below is a summary of the proposed work. Congenital heart defects are among the most common birth defects and the leading cause of death in children born with congenital defects. Understanding how the early embryonic heart functions and what regulatory mechanisms are involved in early cardiogenesis is highly important for advancement of heart defects research. Biomechanical stimuli, including blood flow and heart contraction, are important regulators of ...

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    19. Three-dimensional correction of conduction velocity in the embryonic heart using integrated optical mapping and optical coherence tomography

      Three-dimensional correction of conduction velocity in the embryonic heart using integrated optical mapping and optical coherence tomography

      Optical mapping (OM) of cardiac electrical activity conventionally collects information from a three-dimensional (3-D) surface as a two-dimensional (2-D) projection map. When applied to measurements of the embryonic heart, this method ignores the substantial and complex curvature of the heart surface, resulting in significant errors when calculating conduction velocity, an important electrophysiological parameter. Optical coherence tomography (OCT) is capable of imaging the 3-D structure of the embryonic heart and accurately characterizing the surface topology. We demonstrate an integrated OCT/OM imaging system capable of simultaneous conduction mapping and 3-D structural imaging. From these multimodal data, we obtained 3-D activation maps ...

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    20. Case Western Reserve University Receives NIH Grant for Integrated Imaging of the Form and Function of the Beating Embryonic Heart

      Case Western Reserve University Receives NIH Grant for Integrated Imaging of the Form and Function of the Beating Embryonic Heart

      Case Western Reserve University receives a 2014 NIH grant for $373,641 for Integrated Imaging of the Form and Function of the Beating Embryonic Heart. The principal investigator is Andrew Rollins. The program began in 2006 and ends in 2017. Below is a summary of the prposed work. Congenital heart defects (CHDs) afflict 36,000 babies born in the US each year and survivors often require several surgical interventions in their shortened lifetime. Despite continuous efforts, the mechanisms leading to CHDs remain largely unclear. In part, this is because most developmental cardiology studies fail to address the influential role of ...

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    21. Washington University Receives NIH Grant for Studying Mechanics of Early Brain and Eye Development

      Washington University Receives NIH Grant for Studying Mechanics of Early Brain and Eye Development

      Washington University Receives a 2014 NIH Grant for $332,591 for Studying Mechanics of Early Brain and Eye Development. The principle investigator is Larry Taber. The program beganin 2010 and ends in 2015. Below is a summary of the proposed work. In human embryos, the primary subdivisions of the brain (forebrain, midbrain, and hindbrain) are formed by the fourth week of gestation. During this time, the primitive eyes (optic vesicles) emerge as protrusions from the forebrain. The forms of these organs are highly conserved. Abnormalities in size and shape of the early brain are known to cause serious neurological disorders ...

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    22. Oregon Health & Science University Receives NIH grant to study Dynamic Changes in the Chick Developing Heard in Response to Altered Hemodyanmics

      Oregon Health & Science University Receives NIH grant to study Dynamic Changes in the Chick Developing Heard in Response to Altered Hemodyanmics

      Oregon Health & Science University received at 2014 NIH grant for $404,161 to study Dynamic Changes in the Chick Developing Heard in Response to Altered Hemodyanmics. The principal investigator is Sandra Rugonyi. The program began in 2008 and ends in 2015. Below is a summary of the proposed work. About 1% newborn babies have congenital heart disease (CHD), the leading cause of death among children. The majority of CHD cases are believed not to have a genetic cause. Other factors, such as abnormal blood flow during embryonic and fetal stages can lead to heart malformations and thus CHD through poorly ...

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    23. Microvascular anastomosis in rodent model evaluated by Fourier domain Doppler optical coherence tomography

      Microvascular anastomosis in rodent model evaluated by Fourier domain Doppler optical coherence tomography

      Vascular and microvascular anastomosis are critical components of reconstructive microsurgery, vascular surgery and transplant surgery. Imaging modality that provides immediate, real-time in-depth view and 3D structure and flow information of the surgical site can be a great valuable tool for the surgeon to evaluate surgical outcome following both conventional and innovative anastomosis techniques, thus potentially increase the surgical success rate. Microvascular anastomosis for vessels with outer diameter smaller than 1.0 mm is extremely challenging and effective evaluation of the outcome is very difficult if not impossible using computed tomography (CT) angiograms, magnetic resonance (MR) angiograms and ultrasound Doppler. Optical ...

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    24. Towards a comprehensive eye model for zebrafish retinal imaging using full range spectral domain optical coherence tomography

      Towards a comprehensive eye model for zebrafish retinal imaging using full range spectral domain optical coherence tomography

      In regenerative medicine, the zebrafish is a prominent animal model for studying degeneration and regeneration processes, e.g. of photoreceptor cells in the retina. By means of optical coherence tomography (OCT), these studies can be conducted over weeks using the same individual and hence reducing the variability of the results. To allow an improvement of zebrafish retinal OCT imaging by suitable optics, we developed a zebrafish eye model using geometrical data obtained by in vivo dispersion encoded full range OCT as well as a dispersion comprising gradient index (GRIN) lens model based on refractive index data found in the literature ...

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