1. Articles in category: Developmental Biology

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    1. High-speed ultrahigh-resolution spectral domain optical coherence tomography using high-powersupercontinuum at 0.8 µm wavelength

      High-speed ultrahigh-resolution spectral domain optical coherence tomography using high-powersupercontinuum at 0.8 µm wavelength

      We demonstrated high-speed ultrahigh-resolution (UHR) optical coherence tomography (OCT) in the 800 nm wavelength region. A high-power coherent supercontinuum (SC) and a high-speed line scan camera were used to construct a spectral domain OCT. The axial resolution was 3.1 µm in air and 2.3 µm in tissue. The dependence of sensitivity on the SC power and A-scan rate was examined. For the A-scan rate of 70 kHz, the sensitivity of 104 dB was achieved for the SC power higher than 60 mW. High-speed in vivo UHR-OCT imaging was demonstrated for zebrafish embryo and swimming medaka.

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    2. 4D optical coherence tomography of aortic valve dynamics in a murine mouse model ex vivo

      4D optical coherence tomography of aortic valve dynamics in a murine mouse model ex vivo

      The heart and its mechanical components, especially the heart valves and leaflets, are under enormous strain during lifetime. Like all highly stressed materials, also these biological components undergo fatigue and signs of wear, which impinge upon cardiac output and in the end on health and living comfort of affected patients. Thereby pathophysiological changes of the aortic valve leading to calcific aortic valve stenosis (AVS) as most frequent heart valve disease in humans are of particular interest. The knowledge about changes of the dynamic behavior during the course of this disease and the possibility of early stage diagnosis could lead to ...

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    3. High-resolution three-dimensional in vivo imaging of mouse oviduct using optical coherence tomography

      High-resolution three-dimensional in vivo imaging of mouse oviduct using optical coherence tomography

      The understanding of the reproductive events and the molecular mechanisms regulating fertility and infertility in humans relies heavily on the analysis of the corresponding phenotypes in mouse models. While molecular genetic approaches provide significant insight into the molecular regulation of these processes, the lack of live imaging methods that allow for detailed visualization of the mouse reproductive organs limits our investigations of dynamic events taking place during the ovulation, the fertilization and the pre-implantation stages of embryonic development. Here we introduce an in vivo three-dimensional imaging approach for visualizing the mouse oviduct and reproductive events with micro-scale spatial resolution using ...

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    4. Mapping conduction velocity of early embryonic hearts with a robust fitting algorithm

      Mapping conduction velocity of early embryonic hearts with a robust fitting algorithm

      Cardiac conduction maturation is an important and integral component of heart development. Optical mapping with voltage-sensitive dyes allows sensitive measurements of electrophysiological signals over the entire heart. However, accurate measurements of conduction velocity during early cardiac development is typically hindered by low signal-to-noise ratio (SNR) measurements of action potentials. Here, we present a novel image processing approach based on least squares optimizations, which enables high-resolution, low-noise conduction velocity mapping of smaller tubular hearts. First, the action potential trace measured at each pixel is fit to a curve consisting of two cumulative normal distribution functions. Then, the activation time at each ...

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

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

      Case Western University Receives a 2015 NIH Grant for $359,023 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 proposed 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 altered ...

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    6. Investigating Hemodynamics of the Developing Embryonic Heart using Optical Coherence Tomography (Thesis)

      Investigating Hemodynamics of the Developing Embryonic Heart using Optical Coherence Tomography (Thesis)

      Blood flow is a critical factor that regulates developmental programs during cardiogenesis. During early embryonic development, deviations from the normal blood flow pattern have been shown to lead to congenital heart defects including septal defects and outflow tract anomalies. To better understand the role flow and the resulting hemodynamic forces play during cardiovascular development precise tools are needed to rapidly calculate and monitor these forces. Optical coherence tomography (OCT) is a noninvasive imaging modality that is well suited for imaging the developing heart due to its high spatial and temporal resolution. OCT is also capable of analyzing various cardiac functions ...

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    7. Closed loop tracked Doppler optical coherence tomography based heart monitor for the Drosophila melanogaster larvae

      Closed loop tracked Doppler optical coherence tomography based heart monitor for the Drosophila melanogaster larvae

      A fruit fly larva (top) was continuously tracked for continuous remote monitoring. A heartbeat trace of freely moving larva (bottom) was obtained by a low coherence interferometry based doppler sensing technique. This paper presents a novel instrument for biosciences, useful for studies of moving embryos. A dual sequential imaging/measurement channel is assembled via a closed-loop tracking architecture. The dual channel system can operate in two regimes: (i) single-point Doppler signal monitoring or (ii) fast 3-D swept source OCT imaging. The system is demonstrated for characterizing cardiac dynamics in Drosophila melanogaster larva. Closed loop tracking enables long term in vivo ...

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    8. Quantification of Mouse Embryonic Eye Development with Optical Coherence Tomography In Utero

      Quantification	of	Mouse	Embryonic	Eye	Development	with	 Optical	Coherence	Tomography	In	Utero

      Mouse models are commonly used as research tools to understand regulatory pathways affected by human diseases and disorders. Live imaging tools for visualization of mouse embryonic ocular tissues would be beneficial in research associated with developmental ocular defects. In this study, in utero quantitative assessment of ocular structures in mouse embryos was performed with a swept-source optical coherence tomography (SSOCT). To define developmental changes in eye morphology in live embryos, the volume of the embryonic eye lens and the globe at different embryonic stages ranging from E13.5 to E18.5 was quantified. It is determined that the major axis ...

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    9. Hybrid ultrahigh resolution optical coherence / photoacoustic microscopy

      Hybrid ultrahigh resolution optical coherence / photoacoustic microscopy

      We present an ultrahigh resolution dual modality optical resolution photoacoustic microsopy (OR-PAM) and spectral domain optical coherence microscopy (SD-OCM) system. The ultrahigh sub-micron lateral resolution is provided by the high numerical aperture of the objective lens used while the ultrahigh axial resolution is provided by the broadband OCT laser that covers 107 nm with a central wavelength of 840 nm. The synchronized simultaneous acquisition for the two modalities is achieved using a 40MHz FPGA. 2D-scanning is realized by two orthogonal translation stages (PI, 400 nm resolution). The transversal resolution of the system is 0.5 μm, the axial resolutions are ...

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    10. Measurement of wall shear stress in chick embryonic heart using optical coherence tomography

      Measurement of wall shear stress in chick embryonic heart using optical coherence tomography

      The cardiac development is a complicated process affected by genetic and environmental factors. Wall shear stress (WSS) is one of the components which have been proved to influence the morphogenesis during early stages of cardiac development. To study the mechanism, WSS measurement is a step with significant importance. WSS is caused by blood flow imposed on the inner surface of the heart wall and it can be determined by calculating velocity gradients of blood flow in a direction perpendicular to the wall. However, the WSS of the early stage embryonic heart is difficult to measure since the embryonic heart is ...

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      Mentions: Yi Wang
    11. Approach to quantify two-dimensional strain of chick embryonic heart in early stage based on spectral domain optical coherence tomography

      Approach to quantify two-dimensional strain of chick embryonic heart in early stage based on spectral domain optical coherence tomography

      The heart undergoes remarkable changes during embryonic development due to genetic programming and epigenetic influences, in which mechanical loads is a key factor. As embryonic research development, an important goal is to develop mathematical models that describe the influence of mechanics on embryonic heart development. However, basic parameters for the modeling are difficult to acquire since the embryonic heart is tiny and beating fast in the early stages. Optical coherence tomography (OCT) technique provides depth-resolved image with high resolution and high acquisition speed in a noninvasive manner. In this paper, we performed 4D[(x,y,z) + t] scan on the ...

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      Mentions: Yi Wang
    12. Comparison of optical projection tomography and optical coherence tomography for assessment of murine embryonic development

      Comparison of optical projection tomography and optical coherence tomography for assessment of murine embryonic development

      The murine model is a common model for studying developmental diseases. In this study, we compare the performance of the relatively new method of Optical Projection Tomography (OPT) to the well-established technique of Optical Coherence Tomography (OCT) to assess murine embryonic development at three stages, 9.5, 11.5, and 13.5 days post conception. While both methods can provide spatial resolution at the micrometer scale, OPT can provide superior imaging depth compared to OCT. However, OPT requires samples to be fixed, placed in an immobilization media such as agar, and cleared before imaging. Because OCT does not require fixing ...

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    13. Live dynamic imaging and analysis of developmental cardiac defects in mouse models with optical coherence tomography

      Live dynamic imaging and analysis of developmental cardiac defects in mouse models with optical coherence tomography

      Understanding mouse embryonic development is an invaluable resource for our interpretation of normal human embryology and congenital defects. Our research focuses on developing methods for live imaging and dynamic characterization of early embryonic development in mouse models of human diseases. Using multidisciplinary methods: optical coherence tomography (OCT), live mouse embryo manipulations and static embryo culture, molecular biology, advanced image processing and computational modeling we aim to understand developmental processes. We have developed an OCT based approach to image live early mouse embryos (E8.5 – E9.5) cultured on an imaging stage and visualize developmental events with a spatial resolution of ...

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    14. Investigating the correlation between white matter and microvasculature changes in aging using large scale optical coherence tomography and confocal fluorescence imaging combined with tissue sectioning

      Investigating the correlation between white matter and microvasculature changes in aging using large scale optical coherence tomography and confocal fluorescence imaging combined with tissue sectioning

      Here, we present a serial OCT/confocal scanner for histological study of the mouse brain. Three axis linear stages combined with a sectioning vibratome allows to cut thru the entire biological tissue and to image every section at a microscopic resolution. After acquisition, each OCT volume and confocal image is re-stitched with adjacent acquisitions to obtain a reconstructed, digital volume of the imaged tissue. This imaging platform was used to investigate correlations between white matter and microvasculature changes in aging mice. Three age groups were used in this study (4, 12, 24 months). At sacrifice, mice were transcardially perfused with ...

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    15. Feature Of The Week 02/22/15: Case Western Reserve University Demostrates Using OCT to Rapidly Phenotype and Quantify Congenital Heart Defects Associated with Prenatal Alcohol Exposure

      Feature Of The Week 02/22/15:  Case Western Reserve University Demostrates Using OCT to Rapidly Phenotype and Quantify Congenital Heart Defects Associated with Prenatal Alcohol Exposure

      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. The rapid, consistent imaging protocols allowed for the immediate identification of cardiac anomalies, including ventricular septal defects and misaligned/missing vessels. Interventricular septum ...

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    16. Algorithms for improved 3-D reconstruction of live mammalian embryo vasculature from optical coherence tomography data

      Algorithms for improved 3-D reconstruction of live mammalian embryo vasculature from optical coherence tomography data

      Background: Robust reconstructions of the three-dimensional network of blood vessels in developing embryos imaged by optical coherence tomography (OCT) are needed for quantifying the longitudinal development of vascular networks in live mammalian embryos, in support of developmental cardiovascular research. Past computational methods [such as speckle variance (SV)] have demonstrated the feasibility of vascular reconstruction, but multiple challenges remain including: the presence of vessel structures at multiple spatial scales, thin blood vessels with weak flow, and artifacts resulting from bulk tissue motion (BTM). Methods: In order to overcome these challenges, this paper introduces a robust and scalable reconstruction algorithm based on ...

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    17. Scientists Identify Genetic Cues for a Big Heart

      Scientists Identify Genetic Cues for a Big Heart

      Bigger isn’t always better, even when it comes to the body’s most vital organs. An enlarged or thickened cardiac muscle can actually force the heart to work harder to pump blood throughout the body, weakening the organ until it eventually wears out. Despite the disastrous consequences of oversized organs, researchers have just begun to uncover the circuitry of signals that govern growth. What they do know comes in large part from genes of the tiny fruit fly, Drosophila melanogaster. Over the years, biologists have deleted or suppressed tens of thousands of genes in the fly genome, aptly naming ...

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    18. 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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    19. 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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    20. 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
    21. 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 ...

      Read Full Article
    22. 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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    23. 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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    24. 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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    1-24 of 183 1 2 3 4 5 6 7 8 »
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