1. Articles in category: Developmental Biology

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    1. Long-term in vivo monitoring of injury induced brain regeneration of the adult zebrafish by using spectral domain optical coherence tomography

      Long-term in vivo monitoring of injury induced brain regeneration of the adult zebrafish by using spectral domain optical coherence tomography

      Brain regenerative studies require precise visualization of the morphological structures. However, few imaging methods can effectively detect the adult zebrafish brain in real time with high resolution and good penetration depth. Long-term in vivo monitoring of brain injuries and brain regeneration on adult zebrafish is achieved in this study by using 1325 nm spectral-domain optical coherence tomography (SD-OCT). The SD-OCT is able to noninvasively visualize the skull injury and brain lesion of adult zebrafish. Valuable phenomenon such as the fractured skull, swollen brain tissues, and part of the brain regeneration process can be conducted based on the SD-OCT images at ...

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    2. 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 2016 NIH Grant for $356,784 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 ...

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    3. Live four-dimensional optical coherence tomography reveals embryonic cardiac phenotype in mouse mutant

      Live four-dimensional optical coherence tomography reveals embryonic cardiac phenotype in mouse mutant

      Efficient phenotyping of developmental defects in model organisms is critical for understanding the genetic specification of normal development and congenital abnormalities in humans. We previously reported that optical coherence tomography (OCT) combined with live embryo culture is a valuable tool for mouse embryo imaging and four-dimensional (4-D) cardiodynamic analysis; however, its capability for analysis of mouse mutants with cardiac phenotypes has not been previously explored. Here, we report 4-D (three-dimensional+time) OCT imaging and analysis of the embryonic heart in a Wdr19 mouse mutant, revealing a heart looping defect. Quantitative analysis of cardiac looping revealed a statistically significant difference between ...

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    4. Characterization of zebrafish larvae suction feeding flow using μPIV and optical coherence tomography

      Characterization of zebrafish larvae suction feeding flow using μPIV and optical coherence tomography

      The hydrodynamics of suction feeding is critical for the survival of fish larvae; failure to capture food during the onset of autonomous feeding can rapidly lead to starvation and mortality. Fluid mechanics experiments that investigate the suction feeding of suspended particles are limited to adult fishes, which operate at large Reynolds numbers. This manuscript presents the first literature results in which the external velocity fields generated during suction feeding of early zebrafish larvae (2500–20,000 μm total length) are reported using time-resolved microscopic particle image velocimetry. For the larval stages studied, the maximum peak suction velocity of the inflow ...

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    5. High-resolution contrast-enhanced optical coherence tomography in mice retinae

      High-resolution contrast-enhanced optical coherence tomography in mice retinae

      Optical coherence tomography (OCT) is a noninvasive interferometric imaging modality providing anatomical information at depths of millimeters and a resolution of micrometers. Conventional OCT images limit our knowledge to anatomical structures alone, without any contrast enhancement. Therefore, here we have, for the first time, optimized an OCT-based contrast-enhanced imaging system for imaging single cells and blood vessels in vivo inside the living mouse retina at subnanomolar sensitivity. We used bioconjugated gold nanorods (GNRs) as exogenous OCT contrast agents. Specifically, we used anti-mouse CD45 coated GNRs to label mouse leukocytes and mPEG-coated GNRs to determine sensitivity of GNR detection in vivo ...

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    6. Massachusetts General Hospital Receives NIH Grant for Cardiac MRI-Tractography In Vivo: Integrated Imaging of Structure and Function

      Massachusetts General Hospital Receives NIH Grant for Cardiac MRI-Tractography In Vivo: Integrated Imaging of Structure and Function

      Massachusetts General Hospital Receives a 2016 NIH Grant for $742,986 for Cardiac MRI-Tractography In Vivo: Integrated Imaging of Structure and Function. The principal investigator is David Sosnovik. The program began in 2013 and ends in 2017. Below is a summary of the proposed work. Pressure overload of the left and right ventricles initially leads to adaptive hypertrophy. This, however, is frequently followed by maladaptive hypertrophy, heart failure and death. We hypothesize here that changes in 3D myocardial fiber architecture play a significant role in the deleterious transition from adaptive to maladaptive hypertrophy and heart failure. We further hypothesize that ...

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    7. Optical coherence tomography for embryonic imaging: a review

      Optical coherence tomography for embryonic imaging: a review

      Embryogenesis is a highly complex and dynamic process, and its visualization is crucial for understanding basic physiological processes during development and for identifying and assessing possible defects, malformations, and diseases. While traditional imaging modalities, such as ultrasound biomicroscopy, micro-magnetic resonance imaging, and micro-computed tomography, have long been adapted for embryonic imaging, these techniques generally have limitations in their speed, spatial resolution, and contrast to capture processes such as cardiodynamics during embryogenesis. Optical coherence tomography (OCT) is a noninvasive imaging modality with micrometer-scale spatial resolution and imaging depth up to a few millimeters in tissue. OCT has bridged the gap between ...

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    8. Retroreflective-type Janus microspheres as a novel contrast agent for enhanced optical coherence tomography

      Retroreflective-type Janus microspheres as a novel contrast agent for enhanced optical coherence tomography

      Working principle and SEM image of Janus microsphere (top). Enhanced OCT imaging (bottom) of Janus microspheres in zebrafish stomach (blue dash line) and sinusoids (green arrows) of nude liver. Optical coherence tomography (OCT) is a well-developed technology that utilizes near-infrared light to reconstruct three-dimensional images of biological tissues with micrometer resolution. Improvements of the imaging contrast of the OCT technique are able to further widen its extensive biomedical applications. In this study, Janus microspheres were developed and used as a positive contrast agent for enhanced OCT imaging. Phantom and ex vivo liver tissue experiments as well as in vivo animal ...

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    9. Applicability, usability, and limitations of murine embryonic imaging with optical coherence tomography and optical projection tomography

      Applicability, usability, and limitations of murine embryonic imaging with optical coherence tomography and optical projection tomography

      We present an analysis of imaging murine embryos at various embryonic developmental stages (embryonic day 9.5, 11.5, and 13.5) by optical coherence tomography (OCT) and optical projection tomography (OPT). We demonstrate that while OCT was capable of rapid high-resolution live 3D imaging, its limited penetration depth prevented visualization of deeper structures, particularly in later stage embryos. In contrast, OPT was able to image the whole embryos, but could not be used in vivo because the embryos must be fixed and cleared. Moreover, the fixation process significantly altered the embryo morphology, which was quantified by the volume of ...

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    10. Bright-Field Imaging and Optical Coherence Tomography of the Mouse Posterior Eye

      Bright-Field Imaging and Optical Coherence Tomography of the Mouse Posterior Eye

      Noninvasive live imaging has been used extensively for ocular phenotyping in mouse vision research. Bright-field imaging and optical coherence tomography (OCT) are two methods that are particularly useful for assessing the posterior mouse eye (fundus), including the retina, retinal pigment epithelium, and choroid, and are widely applied due to the commercial availability of sophisticated instruments and software. Here, we provide a guide to using these approaches with an emphasis on post-acquisition image processing using Fiji, a bundled version of the Java-based public domain software ImageJ. A bright-field fundus imaging protocol is described for acquisition of multi-frame videos, followed by image ...

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    11. CUG-BP, Elav-like family member 1 (CELF1) is required for normal myofibrillogenesis, morphogenesis, and contractile function in the embryonic heart

      CUG-BP, Elav-like family member 1 (CELF1) is required for normal myofibrillogenesis, morphogenesis, and contractile function in the embryonic heart

      Background : CUG-BP, Elav-like family member 1 (CELF1) is a multifunctional RNA binding protein found in a variety of adult and embryonic tissues. In the heart, CELF1 is found exclusively in the myocardium. However, the roles of CELF1 during cardiac development have not been completely elucidated. Results : Myofibrillar organization is disrupted and proliferation is reduced following knockdown of CELF1 in cultured chicken primary embryonic cardiomyocytes. In vivo knockdown of Celf1 in developing Xenopus laevis embryos resulted in myofibrillar disorganization and a trend towards reduced proliferation in heart muscle, indicating conserved roles for CELF1 orthologs in embryonic cardiomyocytes. Loss of Celf1 also ...

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    12. Effect of Outflow Tract Banding on Embryonic Cardiac Hemodynamics

      Effect of Outflow Tract Banding on Embryonic Cardiac Hemodynamics

      We analyzed heart wall motion and blood flow dynamics in chicken embryos using in vivo optical coherence tomography (OCT) imaging and computational fluid dynamics (CFD) embryo-specific modeling. We focused on the heart outflow tract (OFT) region of day 3 embryos, and compared normal (control) conditions to conditions after performing an OFT banding intervention, which alters hemodynamics in the embryonic heart and vasculature. We found that hemodynamics and cardiac wall motion in the OFT are affected by banding in ways that might not be intuitive a priori . In addition to the expected increase in ventricular blood pressure, and increase blood flow ...

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    13. 4D imaging of cardiac trabeculae contracting in vitro using gated OCT

      4D imaging of cardiac trabeculae contracting in vitro using gated OCT

      Cardiac trabeculae are widely used as experimental muscle preparations for studying heart muscle. However, their geometry (diameter, length, and shape) can vary not only amongst samples, but also within a sample, leading to inaccuracies in estimating their stress production, volumetric energy output, and/or oxygen consumption. Hence, it is desirable to have a system that can accurately image each trabecula in vitro during an experiment. To this end, we constructed an optical coherence tomography (OCT) system and implemented a gated imaging procedure to image actively contracting trabeculae and reconstruct their time-varying geometry. By imaging a single cross section while monitoring ...

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    14. Michael Jenkins Wins American Association of Anatomists (AAA) Young Investigator Award

      Michael Jenkins Wins American Association of Anatomists (AAA) Young Investigator Award

      Ceremony at AAA's 2016 annual meeting at Experimental Biology (EB) in San Diego, CA. The ceremony is being held at The Marriot Marquis San Diego Marina on Tuesday, April 5, 2016, at 7pm. Young Investigator awards recognize investigators in the early stages of their careers who have made important contributions to biomedical science through their research in cell/molecular biology, comparative neuroanatomy, developmental biology, or the morphological sciences. The 2016 Young Investigator Award winners are:...Michael Jenkins, Ph.D. , of Case Western Reserve University , will be honored with a plaque for his early contributions to the field of developmental ...

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    15. Particle streak velocimetry-optical coherence tomography: a novel method for multidimensional imaging of microscale fluid flows

      Particle streak velocimetry-optical coherence tomography: a novel method for multidimensional imaging of microscale fluid flows

      We present a new OCT method for flow speed quantification and directional velocimetry: particle streak velocimetry-OCT (PSV-OCT). PSV-OCT generates two-dimensional, 2.5-vector component ( v x ,| v y |, v z ) maps of microscale flow velocity fields. Knowledge of 2.5-vector components also enables the estimation of total flow speed. The enabling insight behind PSV-OCT is that tracer particles in sparsely-seeded fluid flow trace out streaks in ( x,z,t )-space. The streak orientations in x-t and z-t yield v x and v z , respectively. The in-plane ( x-z plane) residence time yields the out-of-plane speed | v y |. Vector component values are generated ...

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    16. Four-dimensional live imaging of hemodynamics in mammalian embryonic heart with Doppler optical coherence tomography

      Four-dimensional live imaging of hemodynamics in mammalian embryonic heart with Doppler optical coherence tomography

      Four-dimensional live hemodynamic imaging of the mouse embryonic heart at embryonic day 9.0 using Doppler optical coherence tomography, showing directional blood flows in the sinus venosus, primitive atrium, atrioventricular region and vitelline vein. Hemodynamic analysis of the mouse embryonic heart is essential for understanding the functional aspects of early cardiogenesis and advancing the research in congenital heart defects. However, high-resolution imaging of cardiac hemodynamics in mammalian models remains challenging, primarily due to the dynamic nature and deep location of the embryonic heart. Here we report four-dimensional micro-scale imaging of blood flow in the early mouse embryonic heart, enabling time-resolved ...

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    17. Feature of the Week 03/20/2016: Closed Loop Tracked Doppler OCT Based Heart Monitor for the Drosophila Melanogaster Larvae

      Feature of the Week 03/20/2016: Closed Loop Tracked Doppler OCT 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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    18. Optical coherence tomography for detection of compound action potential in Xenopus Laevis sciatic nerve

      Optical coherence tomography for detection of compound action potential in Xenopus Laevis sciatic nerve

      Due to optical coherence tomography (OCT) high spatial and temporal resolution, this technique could be used to observe the quick changes in the refractive index that accompany action potential. In this study we explore the use of time domain Optical Coherence Tomography (TD-OCT) for real time action potential detection in ex vivo Xenopus Laevis sciatic nerve. TD-OCT is the easiest and less expensive OCT technique and, if successful in detecting real time action potential, it could be used for low cost monitoring devices. A theoretical investigation into the order of magnitude of the signals detected by a TD-OCT setup is ...

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    19. Optical coherence tomography imaging of colonic crypts in a mouse model of colorectal cancer

      Optical coherence tomography imaging of colonic crypts in a mouse model of colorectal cancer

      Aberrant crypt foci (ACF) are abnormal epithelial lesions that precede development of colonic polyps. As the earliest morphological change in the development of colorectal cancer, ACF is a highly studied phenomenon. The most common method of imaging ACF is chromoendoscopy using methylene blue as a contrast agent. Narrow- band imaging is a contrast-agent-free modality for imaging the colonic crypts. Optical coherence tomography (OCT) is an attractive alternative to chromoendoscopy and narrow-band imaging because it can resolve the crypt structure at sufficiently high sampling while simultaneously providing depth-resolved data. We imaged in vivo the distal 15 mm of colon in the ...

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    20. Imaging of the stroke-related changes in the vascular system of the mouse brain with the use of extended focus Optical Coherence Microscopy

      Imaging of the stroke-related changes in the vascular system of the mouse brain with the use of extended focus Optical Coherence Microscopy

      We used Optical Coherence Microscopy (OCM) to monitor structural and functional changes due to ischemic stroke in small animals brains in vivo. To obtain lateral resolution of 2.2 μm over the range of 600 μm we used extended focus configuration of OCM instrument involving Bessel beam. It provided access to detailed 3D information about the changes in brain vascular system up to the level of capillaries across I and II/III layers of neocortex. We used photothrombotic stroke model involving photoactive application of rose bengal to assure minimal invasiveness of the procedure and precise localization of the clot distribution ...

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    21. Measurement of strain and strain rate in embryonic chick heart using spectral domain optical coherence tomography

      Measurement of strain and strain rate in embryonic chick heart using spectral domain optical coherence tomography

      It is important to measure embryonic heart myocardial wall strain and strain rate for understanding the mechanisms of embryonic heart development. Optical coherence tomography (OCT) can provide depth resolved images with high spatial and temporal resolution, which makes it have the potential to reveal the complex myocardial activity in the early stage embryonic heart. We develop a novel method to measure strain in embryonic chick heart based on spectral domain OCT images and subsequent image processing. We perform 4D(x,y,z,t) scanning on the outflow tract (OFT) of chick embryonic hearts in HH18 stage (~3 days of incubation ...

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    22. Blood flowing state analysis in outflow tract of chick embryonic heart based on spectral domain optical coherence tomography

      Blood flowing state analysis in outflow tract of chick embryonic heart based on spectral domain optical coherence tomography

      The cardiac development is a complicated process affected by genetic and environmental factors. Wall shear stress (WSS) and periodic stress (WPS) are the components which have been proved to influence the morphogenesis during early stages of cardiac development. The vessel wall will be deformed by the blood pressure and produce natural elastic force acting on the blood. Because blood flowing in different flow state and show different characteristics of fluid, which influence the calculation of WSS and WPS directly, it is necessary to study the blood flow state. In this paper, we introduce a method to quantify the blood flowing ...

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    23. Label-free imaging of developing vasculature in zebrafish with phase variance optical coherence microscopy

      Label-free imaging of developing vasculature in zebrafish with phase variance optical coherence microscopy

      A phase variance optical coherence microscope (pvOCM) has been created to visualize blood flow in the vasculature of zebrafish embryos, without using exogenous labels. The pvOCM imaging system has axial and lateral resolutions of 2 μm in tissue, and imaging depth of more than 100 μm. Imaging of 2–5 days post-fertilization zebrafish embryos identified the detailed structures of somites, spinal cord, gut and notochord based on intensity contrast. Visualization of the blood flow in the aorta, veins and intersegmental vessels was achieved with phase variance contrast. The pvOCM vasculature images were confirmed with corresponding fluorescence microscopy of a zebrafish ...

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    24. Comparison of rotational imaging optical coherence tomography and selective plane illumination microscopy for embryonic study

      Comparison of rotational imaging optical coherence tomography and selective plane illumination microscopy for embryonic study

      The mouse is a common model for studying developmental diseases. Different optical techniques have been developed to investigate mouse embryos, but each has its own set of limitations and restrictions. In this study, we imaged the same E9.5 mouse embryo with rotational imaging Optical Coherence Tomography (RI-OCT) and Selective Plane Illumination Microscopy (SPIM), and compared the two techniques. Results demonstrate that both methods can provide images with micrometer-scale spatial resolution. The RI-OCT technique was developed to increase imaging depth of OCT by performing traditional OCT imaging at multiple sides and co-registering the images. In SPIM, optical sectioning is achieved ...

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