1. Articles in category: Developmental Biology

    217-237 of 237 « 1 2 3 4 5 6 7 8 9 10
    1. Hemodynamic measurements from individual blood cells in early mammalian embryos with Doppler swept source OCT

      Hemodynamic measurements from individual blood cells in early mammalian embryos with Doppler swept source OCT
      The most common and lethal birth defects affect the cardiovascular (CV) system. The mouse is a superior model for identifying and understanding mammalian CV birth defects, but there is a great need for tools that can detect early and subtle deficiencies in cardiac function in mouse embryos. We combined swept source optical coherence tomography (SS-OCT) with live mouse embryo culture protocols to generate structural two-dimensional and three-dimensional imaging and hemodynamic measurements in a live 8.5 day embryo just a few hours after the beginning of a heartbeat. Our data show that individual circulating blood cells can be visualized with ...
      Read Full Article
    2. Quantitative Measurement of Blood Flow Dynamics in Embryonic Vasculature Using Spectral Doppler Velocimetry

      The biophysical effects of blood flow are known to influence the structure and function of adult cardiovascular systems. Similar effects on the maturation of the cardiovascular system have been difficult to directly and non-invasively measure due to the small size of the embryo. Optical coherence tomography (OCT) has been shown to provide high spatial and temporal structural imaging of the early embryonic chicken heart. We have developed an extension of Doppler OCT, called spectral Doppler velocimetry (SDV), that will enable direct, non-invasive quantification of blood flow and shear rate from the early embryonic cardiovascular system. Using this technique, we calculated ...
      Read Full Article
    3. Optical coherence tomography captures embryonic heart dynamics

      Optical coherence tomography captures embryonic heart dynamics
      An advanced imaging technique has both the spatial and temporal resolution to investigate the developing heart in important animal models such as chicks and mice. In studying the mechanisms that drive early heart formation, researchers rely primarily on static methods such as histology and immunohistochemistry. During cardiac looping, the minuscule heart transforms from a tubular form to a four-chambered heart, a complex process which relies upon mechanical stresses from the functioning heart for feedback. Optical coherence tomography (OCT) imaging emdash a sophisticated, noninvasive technique that can capture detailed images of biological tissue by measuring optical scattering emdash offers the ability ...
      Read Full Article
    4. Sequential en-face optical coherence tomography imaging and monitoring of Drosophila Melanogaster larval heart

      This article demonstrates two modalities to acquire information on cardiac function in larval Drosophila Melanogaster: in-vivo imaging and heartbeat monitoring. To achieve these goals a dedicated imaging instrument able to provide simultaneous en-face Optical Coherence Tomography (OCT) and Laser Sca ... [Proc. SPIE 7168, 71680G (2009)] published Thu Feb 19, 2009.
      Read Full Article
    5. Imaging of cardiovascular dynamics in early mouse embryos with swept source optical coherence tomography

      Imaging of cardiovascular dynamics in early mouse embryos with swept source optical coherence tomography
      Congenital cardiovascular defects are very common, occurring in 1% of live births, and cardiovascular failures are the leading cause of birth defect-related deaths in infants. To improve diagnostics, prevention and treatment of cardiovascular abnormalities, we need to understand not only how cells f ... [Proc. SPIE 7168, 71680E (2009)] published Thu Feb 19, 2009.
      Read Full Article
    6. A new method for detection and quantification of heartbeat parameters in Drosophila, zebrafish, and embryonic mouse hearts

      The genetic basis of heart development is remarkably conserved from Drosophila to mammals, and insights from flies have greatly informed our understanding of vertebrate heart development. Recent evidence suggests that many aspects of heart function are also conserved and the genes involved in heart development also play roles in adult heart function. We have developed a Drosophila heart preparation and movement analysis algorithm that allows quantification of functional parameters. Our methodology combines high-speed optical recording of beating hearts with a robust, semi-automated analysis to accurately detect and quantify, on a beat-to-beat basis, not only heart rate but also diastolic and ...
      Read Full Article
    7. Real-time in vivo imaging of adult Zebrafish brain using optical coherence tomography

      Real-time in vivo imaging of adult Zebrafish brain using optical coherence tomography

      We report noninvasive imaging of the brain of adult Zebrafish (Danio rerio) using real time optical coherence tomography (OCT) capable of acquiring cross sectional 2D OCT images @ 8 frames/sec. Anatomic features such as telencephalon, tectum opticum, eminentia Granularis and cerebellum were clearly resolved in the OCT images. A 3D model of Zebrafish brain was reconstructed, for the first time to our knowledge, using these 2D OCT images.

      Read Full Article
    8. Live imaging of blood flow in mammalian embryos using Doppler swept-source optical coherence tomography

      Live imaging of blood flow in mammalian embryos using Doppler swept-source optical coherence tomography

      Studying hemodynamic changes during early mammalian embryonic development is critical for further advances in prevention, diagnostics, and treatment of congenital cardiovascular (CV) birth defects and diseases. Doppler optical coherence tomography (OCT) has been shown to provide sensitive measurements of blood flow in avian and amphibian embryos. We combined Doppler swept-source optical coherence tomography (DSS-OCT) and live mouse embryo culture to analyze blood flow dynamics in early embryos. SS-OCT structural imaging was used for the reconstruction of embryo morphology and the orientation of blood vessels, which is required for calculating flow velocity from the Doppler measurements. Spatially and temporally resolved blood ...

      Read Full Article
    9. Repeated, noninvasive, high resolution spectral domain optical coherence tomography imaging of zebrafish embryos

      Repeated, noninvasive, high resolution spectral domain optical coherence tomography imaging of zebrafish embryos
      Abstract Purpose: To demonstrate a new imaging method for high resolution spectral domain optical coherence tomography (SD-OCT) for small animal developmental imaging. Methods: Wildtype zebrafish that were 24, 48, 72, and 120 h post fertilization (hpf) and nok gene mutant (48 hpf) embryos were imaged in vivo. Three additional embryos were imaged twice, once at 72 hpf and again at 120 hpf. Images of the developing eye, brain, heart, whole body, proximal yolk sac, distal yolk sac, and tail were acquired. Three-dimensional OCT data sets (501×180 axial scans) were obtained as well as oversampled frames (8,100 axial scans ...
      Read Full Article
    10. Michelson Diagnostics Diversifies into Non-Medical Market

      Michelson Diagnostics Diversifies into Non-Medical Market
      Reacting to strong customer demand, Michelson Diagnostics Ltd (MDL) is broadening the commercial application of its unique 'multibeam' Optical Coherence Tomography (OCT) technology into markets outside its core target of cancer diagnosis. These include such diverse areas as industrial metrology, product inspection, tissue engineering and developmental biology. "We are reacting to customers who have realised that the superior image definition provided by our patented multi-beam OCT technology is very advantageous in their applications", said MDL CEO Jon Holmes. "For a given depth of focus, you get twice the resolution, (or, for a given resolution, four times the focal depth), compared ...
      Read Full Article
    11. Dynamic variation of hemodynamic shear stress on the walls of developing chick hearts: computational models of the heart outflow tract

      Abstract  Heart morphogenesis and growth are influenced by hemodynamic forces (wall shear stress and blood pressure) acting on the walls of the heart. Mechanisms by which hemodynamic forces affect heart development are not well understood, in part because of difficulties involved in measuring these forces in vivo. In this paper, we show how wall shear stress in the heart outflow tract (OFT) of chick embryos at an early developmental stage (HH18) are affected by changes in the geometry and motion of the OFT wall. In particular, we were interested in the effects of cardiac cushions, which are protrusions of the ...
      Read Full Article
    12. Dual-beam Fourier domain optical Doppler tomography of zebrafish

      Dual-beam Fourier domain optical Doppler tomography of zebrafish

      We have developed a dual-beam Fourier domain optical Doppler tomography (FD-ODT) system to image zebrafish (Danio rerio) larvae. Two beams incident on the zebrafish with a fixed angular separation allow absolute blood flow velocity measurement to be made regardless of vessel orientation in a ... [Opt. Express 16, 13624-13636 (2008)]

      Read Full Article
    13. Development of Fourier Domain Optical Coherence Tomography for Applications in Developmental Biology (Thesis)

      Development of Fourier Domain Optical Coherence Tomography for Applications in Developmental Biology (Thesis)
      Developmental biology is a field in which explorations are made to answer how an organism transforms from a single cell to a complex system made up of trillions of highly organized and highly specified cells. This field, however, is not just for discovery, it is crucial for unlocking factors that lead to diseases, defects, or malformations. The one key ingredient that contributes to the success of studies in developmental biology is the technology that is available for use. Optical coherence tomography (OCT) is one such technology. OCT fills a niche between the high resolution of confocal microscopy and deep imaging ...
      Read Full Article
    14. Combining confocal microscopy and optical coherence tomography for imaging in developmental biology

      A. Bradu, Lisha Ma, J. Bloor et al. In-vivo Optical Coherence Tomography (OCT) imaging of the fruit fly Drosophila melanogaster larval heart allows non invasive visualizations and assesment of its cardiac functions. To image Drosophila melanogaster heart, we have developed a dedicated imaging instrument able to provide simultaneous Op ... [Proc. SPIE Int. Soc. Opt. Eng. 6991, 69910K (2008)] published Fri May 2, 2008.
      Read Full Article
    15. Imaging the Embryonic Heart with Optical Coherence Tomography (Thesis)

      Imaging the Embryonic Heart with Optical Coherence Tomography (Thesis)
      Abnormalities that occur during cardiac looping in the early embryo are responsible for congenital heart disease. To date researchers have had to rely upon bioassays, video microscopy and mathematical models to investigate the mechanisms underlying development during looping. Direct observation of looping has been problematic due to the diminutive size (< 2 mm) of the heart and the inability to measure the small and rapid events that influence heart development. Optical coherence tomography (OCT) is a noninvasive imaging tool with the spatiotemporal resolution and field of view to observe both structure and function during the critical time period of looping. Here ...
      Read Full Article
    16. High-resolution in vivo imaging of the cross-sectional deformations of contracting embryonic heart loops using optical coherence tomography

      The embryonic heart tube consists of an outer myocardial tube, a middle layer of cardiac jelly, and an inner endocardial tube. It is said that tubular hearts pump the blood by peristaltoid contractions. The traditional concept of cardiac peristalsis sees the cyclic deformations of pulsating heart tubes as concentric narrowing and widening of tubes of circular cross-section. We have visualized the cross-sectional deformations of contracting embryonic hearts in chick embryos (HH-stages 9-17) using real-time high-resolution optical coherence tomography. Cardiac contractions are detected from HH-stage 10 onward. During the cardiac cycle, the myocardial tube undergoes concentric narrowing and widening while the ...
      Read Full Article
    17. Versatile confocal/optical coherence tomography system for embryonic developmental imaging

      An Optical Coherence Tomography (OCT) imaging system has been designed and constructed to acquire images of scattering biological samples. By simultaneously acquiring and displaying high resolution en-face (C-scan) OCT and Laser Scanning Confocal images of Drosophila melanogaster embryos we demonstrate the potential of the system to be used as a powerful tool for imaging in Drosophila embryonic development. The system can equally be used for non invasive visualizations and measurements of the movement of Drosophila melanogaster larval heart and can easily be switched in the OCT B-scan regime. The confocal channel adds guidance as the specimen can be quickly located ...
      Read Full Article
    18. Optical Coherence Tomography Imaging in Developmental Biology

      Optical Coherence Tomography Imaging in Developmental Biology
      Optical coherence tomography (OCT) is an attractive imaging technique for developmental biology because it permits the imaging of tissue microstructure in situ, yielding micron-scale image resolution without the need for excision of a specimen and tissue processing. OCT enables repeated imaging studies to be performed on the same specimen in order to track developmental changes. OCT is analogous to ultrasound B mode imaging except that it uses low-coherence light rather than sound and performs cross-sectional imaging by measuring the backscattered intensity of light from structures in tissue (1). The principles of OCT imaging are shown schematically in Fig. 1. The ...
      Read Full Article
    19. Measurement of gradient refractive index profile of crystalline lens of fisheye in vivo using optical coherence tomography

      Measurement of gradient refractive index profile of crystalline lens of fisheye in vivo using optical coherence tomography
      We report the use of optical coherence tomography (OCT) for noninvasive measurement of the refractive index profile of a crystalline lens of a fisheye. The approach exploits the fact that OCT provides a direct measurement of the optical path of the light traveled through the medium. The gradient refractive index profile for the crystalline lens was retrieved by iterative fitting of the optical path calculated by the ray tracing method with that experimentally measured using OCT. The estimated error in refractive index is approximately 1%. The measured gradient refractive index and Matthiessen’s ratio (ratio of focal length to lens ...
      Read Full Article
    20. Motion contrast using optical coherence tomography (Thesis)

      Diagnosis of ophthalmic diseases like age-related macular degeneration is very important for treatment of the disease as well as the development of future treatments. Optical coherence tomography (OCT) is an optical interference technique which can measure the three-dimensional structural information of the reflecting layers within a sample. In retinal imaging, OCT is used as the primary diagnostic tool for structural abnormalities such as retinal holes and detachments. The contrast within the images of this technique is based upon reflectivity changes from different regions of the retina. This thesis demonstrates the developments of methods used to produce additional contrast to the ...
      Read Full Article
    217-237 of 237 « 1 2 3 4 5 6 7 8 9 10
  1. Categories

    1. Applications:

      Art, Cardiology, Dentistry, Dermatology, Developmental Biology, Gastroenterology, Gynecology, Microscopy, NDE/NDT, Neurology, Oncology, Ophthalmology, Other Non-Medical, Otolaryngology, Pulmonology, Urology
    2. Business News:

      Acquisition, Clinical Trials, Funding, Other Business News, Partnership, Patents
    3. Technology:

      Broadband Sources, Probes, Tunable Sources
    4. Miscellaneous:

      Jobs & Studentships, Student Theses, Textbooks
  2. Popular Articles

  3. Organizations in the News

    1. (2 articles) University of Houston
    2. (1 articles) University College London
    3. (1 articles) National Institutes of Health
    4. (1 articles) University of Southern California
    5. (1 articles) Baylor College of Medicine
  4. People in the News

    1. (2 articles) Kirill V. Larin
    2. (1 articles) Monica D. Garcia
    3. (1 articles) Scott E. Fraser
    4. (1 articles) Shang Wang
    5. (1 articles) Irina V. Larina