1. Articles in category: Developmental Biology

    145-168 of 246 « 1 2 ... 4 5 6 7 8 9 10 11 »
    1. Two wavelength spectral domain optical coherence tomography systems for early stage chicken embryonic heart imaging

      Two wavelength spectral domain optical coherence tomography systems for early stage chicken embryonic heart imaging

      Blood Flow plays an important role during the early stage development of embryogenesis. Spectral domain optical coherence tomography (SDOCT), with high resolution and high acquisition speed, has been widely used in biological tissue imaging in recent years. By evaluation of phase difference between consecutive A-scan lines, SDOCT provides the ability for flow velocity measurement. In order to find the optimize SDOCT system for early stage chicken embryo heart outflow tract (OFT) flow measurement, two spectral domain optical coherence tomography setups were built in our lab with different central wavelength, i.e. 845nm and 1321nm. The performances of the two systems ...

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    2. A hybrid imaging system for simultaneous ophthalmic optical coherence tomography and dual-channel fluorescence detection in small animal models

      A hybrid imaging system for simultaneous ophthalmic optical coherence tomography and dual-channel fluorescence detection in small animal models

      We present a novel hybrid system that allows simultaneous high-resolution spectral domain optical coherence tomography (OCT) in the near-infrared and single-photon excited fluorescence (SPEF) detection in the green and red visible wavelength range for non-invasive multimodal imaging of the retina in small in vivo animal models such as zebrafish.

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    3. Biomechanics of the Chick Embryonic Heart Outflow Tract at HH18 Using 4D Optical Coherence Tomography Imaging and Computational Modeling

      Biomechanics of the Chick Embryonic Heart Outflow Tract at HH18 Using 4D Optical Coherence Tomography Imaging and Computational Modeling

      During developmental stages, biomechanical stimuli on cardiac cells modulate genetic programs, and deviations from normal stimuli can lead to cardiac defects. Therefore, it is important to characterize normal cardiac biomechanical stimuli during early developmental stages. Using the chicken embryo model of cardiac development, we focused on characterizing biomechanical stimuli on the Hamburger–Hamilton (HH) 18 chick cardiac outflow tract (OFT), the distal portion of the heart from which a large portion of defects observed in humans originate. To characterize biomechanical stimuli in the OFT, we used a combination of in vivo optical coherence tomography (OCT) imaging, physiological measurements and computational ...

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    4. Feature Of The Week 7/22/12: Label-Free Subcellular 3D Live Imaging of Preimplantation Mouse Embryos With Full-Field Optical Coherence Tomography

      Feature Of The Week 7/22/12: Label-Free Subcellular 3D Live Imaging of Preimplantation Mouse Embryos With Full-Field Optical Coherence Tomography

      arly patterning and polarity is of fundamental interest in preimplantation embryonic development. Label-free subcellular 3D live imaging is very helpful to its related studies. We have developed a novel system of full-field optical coherence tomography (FF-OCT) for noninvasive 3D subcellular live imaging of preimplantation mouse embryos with no need of dye labeling. 3D digitized embryos can be obtained by image processing. Label-free 3D live imaging is demonstrated for the mouse embryos at various typical preimplantation stages with a spatial resolution of 0.7 µm and imaging rate of 24 fps. Factors that relate to early patterning and polarity, such as ...

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    5. A more accurate and noninvasive look at cancerous tumors

      A more accurate and noninvasive look at cancerous tumors

      Lehigh University Press Release - Chao Zhou believes his work with combining imaging technologies has the potential to improve surgeries that remove malignant breast tumors. “As many as 40 percent of breast cancer patients now have to undergo a second surgery, because part of the tumor is left behind during the first,” says Zhou , an assistant professor of electrical and computer engineering. By combining two technologies—optical coherence tomography (OCT) and confocal microscopy—Zhou says doctors can more precisely pinpoint a tumor’s location and remove it entirely on the first try. One advantage of this hybrid approach, he says, is ...

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    6. Label-free subcellular 3D live imaging of preimplantation mouse embryos with full-field optical coherence tomography

      Label-free subcellular 3D live imaging of preimplantation mouse embryos with full-field optical coherence tomography

      Early patterning and polarity is of fundamental interest in preimplantation embryonic development. Label-free subcellular 3D live imaging is very helpful to its related studies. We have developed a novel system of full-field optical coherence tomography (FF-OCT) for noninvasive 3D subcellular live imaging of preimplantation mouse embryos with no need of dye labeling. 3D digitized embryos can be obtained by image processing. Label-free 3D live imaging is demonstrated for the mouse embryos at various typical preimplantation stages with a spatial resolution of 0.7 µm and imaging rate of 24 fps. Factors that relate to early patterning and polarity, such as ...

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    7. Case Western Reserve University Wins NIH Grant for Investigating the Early Embryonic Murine Heart Using Optical Coherence Tomography

      Case Western Reserve University Wins NIH Grant for Investigating the Early Embryonic Murine Heart Using Optical Coherence Tomography

      Case Western Reserve University received a 2012 NIH Grant for $712,087 for investigating the early embroyonic murine heart using optical coherence tomography. The project is part of a multiyear grant that began in 2009 and ends in 2013. The principle investigator is Andrew Rollins. Below is a summary of the proposed work.    The embryonic murine heart is a very important model of human heart development due to its four- chambered structure similar to the human heart, a short gestation period and a completely mapped genome which is easy to alter and manipulate. Lack of an appropriate imaging technology has ...

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    8. Practical approach for dispersion compensation in spectral-domain optical coherence tomography

      Practical approach for dispersion compensation in spectral-domain optical coherence tomography

      e proposed and demonstrated a digital method of dispersion compensation suitable for spectral-domain optical coherence tomography. The wavelength coordinate of the coherence spectrum was calibrated digitally using a two-order polynomial. A software-based scheme was introduced to determine the polynomial coefficients of the polynomial fitting spectrum wavelength. Therefore, the spectrum deformation introduced by dispersion can be compensated effectively. This method was experimentally validated by in vivo imaging an early-stage chick embryonic heart.

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      Mentions: Yi Wang
    9. Longitudinal Imaging of Heart Development With Optical Coherence Tomography

      Longitudinal Imaging of Heart Development With Optical Coherence Tomography

      Optical coherence tomography (OCT) has great potential for deciphering the role of mechanics in normal and abnormal heart development. OCT images tissue microstructure and blood flow deep into the tissue (1-2 mm) at high spatiotemporal resolutions allowing unprecedented images of the developing heart. Here, we review the advancement of OCT technology to image heart development and report some of our recent findings utilizing OCT imaging under environmental control for longitudinal imaging. Precise control of the environment is absolutely required in longitudinal studies that follow the growth of the embryo or studies comparing normal versus perturbed heart development to obtain meaningful ...

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    10. Imaging of oocyte development using ultrahigh-resolution full-field optical coherence tomography

      Imaging of oocyte development using ultrahigh-resolution full-field optical coherence tomography

      In this paper, a white-light full-field optical coherence tomography is developed to provide three-dimensional imaging of the development of a mouse embryo with ultrahigh-resolution. Spatial resolution of 1.8  μm×1.12  μm (transverse×axial ) is achieved owing to the extremely short coherence length of the light source and optimized compensation of dispersion mismatch. A shot-noise limited detection sensitivity of 80 dB is obtained at an acquisition time of 5 seconds per image. To enable in vivo imaging of the mouse embryo development, a homemade incubator is applied to provide appropriate CO 2 concentration, temperature, and humidity. An electronic light ...

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    11. Gated optical coherence tomography (OCT) environmental chamber

      Gated optical coherence tomography (OCT) environmental chamber

      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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    12. Optical coherence tomography for live phenotypic analysis of embryonic ocular structures in mouse models

      Optical coherence tomography for live phenotypic analysis of embryonic ocular structures in mouse models

      Mouse models of ocular diseases provide a powerful resource for exploration of molecular regulation of eye development and pre-clinical studies. Availability of a live high-resolution imaging method for mouse embryonic eyes would significantly enhance longitudinal analyses and high-throughput morphological screening. We demonstrate that optical coherence tomography (OCT) can be used for live embryonic ocular imaging throughout gestation. At all studied stages, the whole eye is within the imaging distance of the system and there is a good optical contrast between the structures. We also performed OCT eye imaging in the embryonic retinoblastoma mouse model Pax6-SV40 T-antigen, which spontaneously forms lens ...

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    13. Long-Term Characterization of Retinal Degeneration in rd1 and rd10 Mice Using Spectral Domain Optical Coherence Tomography

      Long-Term Characterization of Retinal Degeneration in rd1 and rd10 Mice Using Spectral Domain Optical Coherence Tomography

      Purpose. To characterize the in vivo changes over time in the retinal structure of wild-type mice alongside two lines of mice deficient in the ß-subunit of phosphodiesterase (rd1 and rd10 mice) using Spectral Domain Optical Coherence Tomography (SD-OCT). Methods. SD-OCT images were obtained using the Bioptigen Spectral Domain Ophthalmic Imaging System (SDOIS). Wild-type C57BL/6J, rd1 and rd10 mice ranging in age from P14 to P206 were sedated with 1% isoflurane. Horizontal and vertical linear scans through the optic nerve and annular scans around the optic nerve were obtained. Results. SD-OCT imaging of wild-type mice demonstrated visibility of the inner ...

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    14. Speckle variance optical coherence tomography of the rodent spinal cord: in vivo feasibility

      Speckle variance optical coherence tomography of the rodent spinal cord: in vivo feasibility

      Optical coherence tomography (OCT) has the combined advantage of high temporal (µsec) and spatial (less than 10µm) resolution. These features make it an attractive tool to study the dynamic relationship between neural activity and the surrounding blood vessels in the spinal cord, a topic that is poorly understood. Here we present work that aims to optimize an in vivo OCT imaging model of the rodent spinal cord. In this study we image the microvascular networks of both rats and mice using speckle variance OCT. This is the first report of depth resolved imaging of the in vivo spinal cord using ...

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    15. Comparative intrinsic optical signal imaging of wild-type and mutant mouse retinas

      Comparative intrinsic optical signal imaging of wild-type and mutant mouse retinas

      Functional measurement is important for retinal study and disease diagnosis. Transient intrinsic optical signal (IOS) response, tightly correlated with functional stimulation, has been previously detected in normal retinas. In this paper, comparative IOS imaging of wild-type (WT) and rod-degenerated mutant mouse retinas is reported. Both 2-month and 1-year-old mice were measured. In 2-month-old mutant mice, time course and peak value of the stimulus-evoked IOS were significantly delayed (relative to stimulus onset) and reduced, respectively, compared to age matched WT mice. In 1-year-old mutant mice, stimulus-evoked IOS was totally absent. However, enhanced spontaneous IOS responses, which might reflect inner neural remodeling ...

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    16. Full field optical coherence tomography can identify spermatogenesis in a rodent sertoli-cell only model

      Full field optical coherence tomography can identify spermatogenesis in a rodent sertoli-cell only model

      Background: Microdissection testicular sperm extraction (micro-TESE) has replaced conventional testis biopsies as a method of choice for obtaining sperm for in vitro fertilization for men with nonobstructive azoospermia. A technical challenge of micro-TESE is that the low magnification inspection of the tubules with a surgical microscope is insufficient to definitively identify sperm-containing tubules, necessitating tissue removal and cytologic assessment. Full field optical coherence tomography (FFOCT) uses white light interference microscopy to generate quick high-resolution tomographic images of fresh (unprocessed and unstained) tissue. Furthermore, by using a nonlaser safe light source (150 W halogen lamp) for tissue illumination, it ensures that ...

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    17. Deletion of Siah-interacting protein gene in Drosophila causes cardiomyopathy

      Deletion of Siah-interacting protein gene in Drosophila causes cardiomyopathy

      Drosophila is a useful model organism in which the genetics of human diseases, including recent advances in identification of the genetics of heart development and disease in the fly, can be studied. To identify novel genes that cause cardiomyopathy, we performed a deficiency screen in adult Drosophila. Using optical coherence tomography to phenotype cardiac function in awake adult Drosophila, we identified Df(1)Exel6240 as having cardiomyopathy. Using a number of strategies including customized smaller deletions, screening of mutant alleles, and transgenic rescue, we identified CG3226 as the causative gene for this deficiency. CG3226 is an uncharacterized gene in Drosophila ...

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      Mentions: Duke University
    18. Sequential Turning Acquisition and Reconstruction (STAR) method for four-dimensional imaging of cyclically moving structures

      Sequential Turning Acquisition and Reconstruction (STAR) method for four-dimensional imaging of cyclically moving structures

      Optical coherence tomography allows for dynamic, three-dimensional (3D+T) imaging of the heart within animal embryos. However, direct 3D+T imaging frame rates remain insufficient for cardiodynamic analysis. Previously, this limitation has been addressed by reconstructing 3D+T representations of the beating heart based on sets of two-dimensional image sequences (2D+T) acquired sequentially at high frame rate and in fixed (and parallel) planes throughout the heart. These methods either require additional hardware to trigger the acquisition of each 2D+T series to the same phase of the cardiac cycle or accumulate registration errors as the slices are synchronized retrospectively ...

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    19. 4D imaging of embryonic chick hearts by streak-mode Fourier domain optical coherence tomography

      4D imaging of embryonic chick hearts by streak-mode Fourier domain optical coherence tomography

      Recently, we developed the streak-mode Fourier domain optical coherence tomography (OCT) technique in which an area-scan camera is used in a streak-mode to record the OCT spectrum. Here we report the application of this technique to in ovo imaging HH18 embryonic chick hearts with an ultrahigh speed of 1,016,000 axial scans per second. The high-scan rate enables the acquisition of high temporal resolution 2D datasets (1,000 frames per second or 1 ms between frames) and 3D datasets (10 volumes per second), without use of prospective or retrospective gating technique. This marks the first time that the embryonic ...

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    20. 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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    21. Prenatal imaging of distal limb abnormalities using OCT in mice

      Prenatal imaging of distal limb abnormalities using OCT in mice

      Congenital abnormalities of the limbs are common birth defects. These include missing or extra fingers or toes, abnormal limb length, and abnormalities in patterning of bones, cartilage or muscles. Optical Coherence Tomography (OCT) is a 3-D imaging modality, which can produce high-resolution (~8 μm) images of developing embryos with an imaging depth of a few millimeters. Here we demonstrate the capability of OCT to perform 3D imaging of limb development in normal embryos and a mouse model with congenital abnormalities. Our results suggest that OCT is a promising tool to analyze embryonic limb development in mammalian models of congenital defects.

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    22. Optical coherence tomography captures rapid hemodynamic responses to acute hypoxia of the embryonic cardiovascular system of Early Embryos

      Optical coherence tomography captures rapid hemodynamic responses to acute hypoxia of the embryonic cardiovascular system of Early Embryos

      Background.The trajectory to heart defects may start in tubular and looping heart stages when detailed analysis of form and function is difficult by currently available methods. We used a novel method, Doppler optical coherence tomography (OCT), to follow changes in cardiovascular function in quail embryos during acute hypoxic stress. Chronic fetal hypoxia is a known risk factor for congenital heart diseases (CHDs). Decreased fetal heart rates during maternal obstructive sleep apnea suggest that studying fetal heart responses under acute hypoxia is warranted.Results.We captured responses to hypoxia at the critical looping heart stages. Doppler OCT revealed detailed vitelline ...

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    23. Label-free in utero imaging of mouse embryos

      Label-free in utero imaging of mouse embryos
      The mouse is a classic mammalian model used to study the anatomical and physiological development of different organ systems. Hundreds of mouse mutants associated with human diseases have been reported, helping to advance our understanding of the genetic basis of development and disease. Moreover, the proven value of genetic approaches to study gene function in the mouse, and the efficiency with which individual mutations can be mapped and cloned, has led to several large-scale, international, genome-wide screens for new and advanced models of human disease. Traditionally, primary analysis of embryonic mutant phenotypes has been based on static examination of histological ...
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    24. Spectral domain optical coherence tomography for embryo heart flow measurement

      Spectral domain optical coherence tomography for embryo heart flow measurement
      The measurement of blood-plasma velocity distributions with high spatial and temporal resolution in vivo is important for the investigation of embryonic heart at its early stage development. Optical Coherence Tomography is a non-invasive imaging modality with high resolution (5 to 20 μm) that can provide flow velocity information by calculating the Doppler frequency shift. In this paper, a high speed spectral optical coherence tomography system was demonstrated. An achievable scanning speed of 92k line/sec has been reached by using an ultra-high speed linear array CCD camera. The measurable flow velocity range is [-24,24]mm/s using this system ...
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    145-168 of 246 « 1 2 ... 4 5 6 7 8 9 10 11 »
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