1. Articles in category: Developmental Biology

    1-24 of 258 1 2 3 4 ... 9 10 11 »
    1. Heart-rate sensitive optical coherence angiography for measuring vascular changes due to posttraumatic brain injury in micecal coherence tomography findings in Parkinson's disease

      Heart-rate sensitive optical coherence angiography for measuring vascular changes due to posttraumatic brain injury in micecal coherence tomography findings in Parkinson's disease

      Traumatic brain injury (TBI) results in direct vascular disruption, triggering edema, and reduction in cerebral blood flow. Therefore, understanding the pathophysiology of brain microcirculation following TBI is important for the development of effective therapies. Optical coherence angiography (OCA) is a promising tool for evaluating TBI in rodent models. We develop an approach to OCA that uses the heart-rate frequency to discriminate between static tissue and vasculature. This method operates on intensity data and is therefore not phase sensitive. Furthermore, it does not require spatial overlap of voxels and thus can be applied to pre-existing datasets for which oversampling may not ...

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    2. Müller Glia Cell Activation in a Laser-induced Retinal Degeneration and Regeneration Model in Zebrafish

      Müller Glia Cell Activation in a Laser-induced Retinal Degeneration and Regeneration Model in Zebrafish

      A fascinating difference between teleost and mammals is the lifelong potential of the teleost retina for retinal neurogenesis and regeneration after severe damage. Investigating the regeneration pathways in zebrafish might bring new insights to develop innovative strategies for the treatment of retinal degenerative diseases in mammals. Herein, we focused on the induction of a focal lesion to the outer retina in adult zebrafish by means of a 532 nm diode laser. A localized injury allows investigating biological processes that take place during retinal degeneration and regeneration directly at the area of damage. Using non-invasive optical coherence tomography (OCT), we were ...

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    3. Measurement of the absolute velocity of blood flow in early-stage chick embryos using spectral domain optical coherence tomography

      Measurement of the absolute velocity of blood flow in early-stage chick embryos using spectral domain optical coherence tomography

      Doppler optical coherence tomography (OCT) is a noninvasive imaging modality that provides quantitative flow information with high spatial and temporal resolution. However, it is only sensitive to the flow velocity vector parallel to the incident beam. To calculate the absolute velocity, it is necessary to obtain the angle between the incident beam and flow field. In this paper, we describe a practical method to measure the Doppler angle based on the structural information of blood vessels extracted from spectral domain OCT images. In this method, a normal sectional scan of the vessel is performed where the probe beam is perpendicular ...

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    4. Feature Of The Week 10/08/2017: Optical Coherence Microscopy as a Novel, Non-Invasive Method for the 4D Live Imaging of Early Mammalian Embryos

      Feature Of The Week 10/08/2017: Optical Coherence Microscopy as a Novel, Non-Invasive Method for the 4D Live Imaging of Early Mammalian Embryos

      Imaging of living cells based on traditional fluorescence and confocal laser scanning microscopy has delivered an enormous amount of information critical for understanding biological processes in single cells. However, the requirement for a high numerical aperture and fluorescent markers still limits researchers’ ability to visualize the cellular architecture without causing short- and long-term photodamage. Optical coherence microscopy (OCM) is a promising alternative that circumvents the technical limitations of fluorescence imaging techniques and provides unique access to fundamental aspects of early embryonic development, without the requirement for sample pre-processing or labeling. In the present paper, we utilized the internal motion of ...

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

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

      Several optical imaging techniques have been applied for high-resolution embryonic imaging using different contrast mechanisms, each with their own benefits and limitations. 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). RI-OCT overcomes optical penetration limits of traditional OCT imaging that prohibit full-body imaging of mouse embryos at later stages by imaging the samples from multiple angles. SPIM enables high-resolution, 3D imaging with less phototoxicity and photobleaching than laser scanning confocal microscopy (LSCM) by illuminating the sample with a focused sheet of light. Side by ...

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    6. Evaluating biomechanical properties of murine embryos using Brillouin microscopy and optical coherence tomography

      Evaluating biomechanical properties of murine embryos using Brillouin microscopy and optical coherence tomography

      Embryogenesis is regulated by numerous changes in mechanical properties of the cellular microenvironment. Thus, studying embryonic mechanophysiology can provide a more thorough perspective of embryonic development, potentially improving early detection of congenital abnormalities as well as evaluating and developing therapeutic interventions. A number of methods and techniques have been used to study cellular biomechanical properties during embryogenesis. While some of these techniques are invasive or involve the use of external agents, others are compromised in terms of spatial and temporal resolutions. We propose the use of Brillouin microscopy in combination with optical coherence tomography (OCT) to measure stiffness as well ...

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    7. Whole mouse brain imaging using optical coherence tomography: reconstruction, normalization, segmentation, and comparison with diffusion MRI

      Whole mouse brain imaging using optical coherence tomography: reconstruction, normalization, segmentation, and comparison with diffusion MRI

      An automated massive histology setup combined with an optical coherence tomography (OCT) microscope was used to image a total of n = 5 n=5 whole mouse brains. Each acquisition generated a dataset of thousands of OCT volumetric tiles at a sampling resolution of 4.9 × 4.9 × 6.5    μ m 4.9×4.9×6.5  μm . This paper describes techniques for reconstruction and segmentation of the sliced brains. In addition to the measured OCT optical reflectivity, a single scattering photon model was used to compute the attenuation coefficients within each tissue slice. Average mouse brain templates were generated for ...

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    8. Computer-aided detection and quantification of endolymphatic hydrops within the mouse cochlea in vivo using optical coherence tomography

      Computer-aided detection and quantification of endolymphatic hydrops within the mouse cochlea in vivo using optical coherence tomography

      Diseases that cause hearing loss and/or vertigo in humans such as Meniere’s disease are often studied using animal models. The volume of endolymph within the inner ear varies with these diseases. Here, we used a mouse model of increased endolymph volume, endolymphatic hydrops, to develop a computer-aided objective approach to measure endolymph volume from images collected in vivo using optical coherence tomography. The displacement of Reissner’s membrane from its normal position was measured in cochlear cross sections. We validated our computer-aided measurements with manual measurements and with trained observer labels. This approach allows for computer-aided detection of ...

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    9. Optical coherence microscopy as a novel, non-invasive method for the 4D live imaging of early mammalian embryos

      Optical coherence microscopy as a novel, non-invasive method for the 4D live imaging of early mammalian embryos

      Imaging of living cells based on traditional fluorescence and confocal laser scanning microscopy has delivered an enormous amount of information critical for understanding biological processes in single cells. However, the requirement for a high numerical aperture and fluorescent markers still limits researchers’ ability to visualize the cellular architecture without causing short- and long-term photodamage. Optical coherence microscopy (OCM) is a promising alternative that circumvents the technical limitations of fluorescence imaging techniques and provides unique access to fundamental aspects of early embryonic development, without the requirement for sample pre-processing or labeling. In the present paper, we utilized the internal motion of ...

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    10. A Better View of Blood-Vessel Development

      A Better View of Blood-Vessel Development

      A research team in China has exploited photoacoustic imaging to track development of the circulatory system in zebrafish embryos, without the use of labels or contrast agents that can gum up the view of sensitive biological processes (Biomed. Opt. Express, doi: 10.1364/BOE.8.002359 ). The researchers believe that this proof of concept in one of biomedicine’s central model organisms could open a path in the future toward using the technique to study human cardiovascular diseases, as well as brain diseases tied to blood-flow issues.

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    11. OHSU Receives NIH Grant for Dynamic Changes in the Chick Developing Heart in Response to Altered Hemodynamics

      OHSU Receives NIH Grant for Dynamic Changes in the Chick Developing Heart in Response to Altered Hemodynamics

      Oregon Health & Science University Receives a 2017 NIH Grant for $414,360 for Dynamic Changes in the Chick Developing Heart in Response to Altered Hemodynamics. The principal investigator is Sandra Rugonyi. The program began in 2008 and ends in 2018. Below is a summary of the proposed work. Project Summary 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 ...

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    12. UCDavis Receives NIH Grant for Improving Penetration Depth and Spatial Resolution for In Vivo Deep Imaging of Mouse Brain Using 2200nm Optical Coherence Microscopy

      UCDavis Receives NIH Grant for Improving Penetration Depth and Spatial Resolution for In Vivo Deep Imaging of Mouse Brain Using 2200nm Optical Coherence Microscopy

      University of California at Davis Receives a 2017 NIH Grant for $78,500 for Improving Penetration Depth and Spatial Resolution for In Vivo Deep Imaging of Mouse Brain Using 2200nm Optical Coherence Microscopy. The principal investigator is Shau Chong. The program began in 20-17 and ends in 2-019. Below is a summary of the proposed work. Subcortical pathology is a common feature in aging, Alzheimer's disease and vascular dementia but has been challenging to study with micron resolution in vivo. Optical methods such as two-photon microscopy image the superficial cortex at the micron-scale, but the resolution of these conventional ...

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    13. Heart structural remodeling in a mouse model of Duchenne cardiomyopathy revealed using optical polarization tractography [Invited]

      Heart structural remodeling in a mouse model of Duchenne cardiomyopathy revealed using optical polarization tractography [Invited]

      We investigated the heart structural remodeling in the mdx4cv mouse model of Duchenne cardiomyopathy using optical polarization tractography. Whole heart tractography was obtained in freshly dissected hearts from six mdx4cv mice. Six hearts from C57BL/6J mice were also imaged as the normal control. The mdx4cv hearts were significantly larger than the control hearts and had significantly higher between–subject variations in myofiber organization. While both strains showed classic cross-helical fiber organization in the left ventricle, the rate of the myocardial fiber orientation change across the heart wall was significantly altered in the right ventricle of the mdx4cv heart.

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    14. OCT intensity and phase fluctuations correlated with activity-dependent neuronal calcium dynamics in the Drosophila CNS [Invited]

      OCT intensity and phase fluctuations correlated with activity-dependent neuronal calcium dynamics in the Drosophila CNS [Invited]

      Phase-resolved OCT and fluorescence microscopy were used simultaneously to examine stereotypic patterns of neural activity in the isolated Drosophila central nervous system. Both imaging modalities were focused on individually identified bursicon neurons known to be involved in a fixed action pattern initiated by ecdysis-triggering hormone. We observed clear correspondence of OCT intensity, phase fluctuations, and activity-dependent calcium-induced fluorescence.

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    15. Automated feature extraction for retinal vascular biometry in zebrafish using OCT angiography

      Automated feature extraction for retinal vascular biometry in zebrafish using OCT angiography

      Zebrafish have been identified as an ideal model for angiogenesis because of anatomical and functional similarities with other vertebrates. The scale and complexity of zebrafish assays are limited by the need to manually treat and serially screen animals, and recent technological advances have focused on automation and improving throughput. Here, we use optical coherence tomography (OCT) and OCT angiography (OCT-A) to perform noninvasive, in vivo imaging of retinal vasculature in zebrafish. OCT-A summed voxel projections were low pass filtered and skeletonized to create an en face vascular map prior to connectivity analysis. Vascular segmentation was referenced to the optic nerve ...

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    16. Optical coherence microscopy with extended focus for in vivo embryonic imaging

      Optical coherence microscopy with extended focus for in vivo embryonic imaging

      Optical coherence microscopy (OCM) has unique advantages of high-resolution volumetric imaging without relying on exogenous labels or dyes. It combines the coherence-gated depth discrimination of optical coherence tomography (OCT) with the high lateral resolution of confocal microscopy, offering an excellent balance between the resolutions and imaging depth. However, as the lateral resolution becomes higher, the imaging depth of OCM decreases and its three-dimensional imaging capability is greatly degraded. To overcome this limitation, we used amplitude apodization to create quasi-Bessel beam illumination in order to extend the depth of focus. The lateral and axial resolutions of our OCM system were measured ...

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    17. Dynamic multimodal full-field optical coherence tomography and fluorescence structured illumination microscopy

      Dynamic multimodal full-field optical coherence tomography and fluorescence structured illumination microscopy

      We report on the development of a configuration of a multimodal full-field optical coherence tomography (FF-OCT) and fluorescence microscope. Our system can simultaneously acquire FF-OCT and structured illumination microscopy images. Dynamic parallel evolution of tissue microstructures and biochemical environments can be visualized. We use high numerical aperture objectives to optimize the combination of the two modalities. We imaged the propagation of mechanical waves initiated by calcium waves in a heart wall to illustrate the interest of simultaneous recording of mechanical and biochemical information.

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    18. A dual-modality optical coherence tomography and selective plane illumination microscopy system for mouse embryonic imaging

      A dual-modality optical coherence tomography and selective plane illumination microscopy system for mouse embryonic imaging

      Both optical coherence tomography (OCT) and selective plane illumination microscopy (SPIM) are frequently used in mouse embryonic research for high-resolution three-dimensional imaging. However, each of these imaging methods provide a unique and independent advantage: SPIM provides morpho-functional information through immunofluorescence and OCT provides a method for whole-embryo 3D imaging. In this study, we have combined rotational imaging OCT and SPIM into a single, dual-modality device to image E9.5 mouse embryos. The results demonstrate that the dual-modality setup is able to provide both anatomical and functional information simultaneously for more comprehensive tissue characterization

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    19. Live dynamic analysis of the developing cardiovascular system in mice

      Live dynamic analysis of the developing cardiovascular system in mice

      The study of the developing cardiovascular system in mice is important for understanding human cardiogenesis and congenital heart defects. Our research focuses on imaging early development in the mouse embryo to specifically understand cardiovascular development under the regulation of dynamic factors like contractile force and blood flow using optical coherence tomography (OCT). We have previously developed an OCT based approach that combines static embryo culture and advanced image processing with computational modeling to live-image mouse embryos and obtain 4D (3D+time) cardiodynamic datasets. Here we present live 4D dynamic blood flow imaging of the early embryonic mouse heart in correlation ...

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    20. Analysis of Craniocardiac Malformations in Xenopus using Optical Coherence Tomography : Scientific Reports

      Analysis of Craniocardiac Malformations in Xenopus using Optical Coherence Tomography : Scientific Reports

      Birth defects affect 3% of children in the United States. Among the birth defects, congenital heart disease and craniofacial malformations are major causes of mortality and morbidity. Unfortunately, the genetic mechanisms underlying craniocardiac malformations remain largely uncharacterized. To address this, human genomic studies are identifying sequence variations in patients, resulting in numerous candidate genes. However, the molecular mechanisms of pathogenesis for most candidate genes are unknown. Therefore, there is a need for functional analyses in rapid and efficient animal models of human disease. Here, we coupled the frog Xenopus tropicalis with Optical Coherence Tomography (OCT) to create a fast and ...

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    21. Stanford faculty named in first cohort of Chan Zuckerberg Biohub investigators

      Stanford faculty named in first cohort of Chan Zuckerberg Biohub investigators

      The Chan Zuckerberg Biohub committed more than $50 million to support 47 of the best investigators from Bay Area universities, including 19 from Stanford University. The investigators each receive five-year appointments worth up to $1.5 million to carry out non-conventional scientific exploration and to invent new tools to accelerate the pace of discovery. De la Zerda’s goal is to image 100 million cells in living tissues at single-cell resolution by using optical coherence tomography. One of the potential uses of his technique will be to visualize cancer markers to delineate the margins of tumors.

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    22. The University of Houston Receives NIH Grant for Optical Coherence Tomography to Study Effect of Poly-Drug Exposure on Fetal Brain Development

      The University of Houston Receives NIH Grant for Optical Coherence Tomography to Study Effect of Poly-Drug Exposure on Fetal Brain Development

      The University of Houston Receives a 2017 NIH Grant for $311,241 for Optical Coherence Tomography to Study Effect of Poly-Drug Exposure on Fetal Brain Development. The principal investigator is Kirll Larin. The program began in 2016 and ends in 2020. Below is a summary of the proposed work. The overall objective of this study is to develop an optical coherence tomography (OCT) based high- resolution mouse embryonic brain imaging and analysis approach, and to use this method in correlation with molecular analysis to understand the interplay between ethanol (EtOH) and nicotine (NIC) effects on embryonic brain development. Maternal exposures ...

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    23. Spectral Domain Optical Coherence Tomography: An In Vivo Imaging Protocol for Assessing Retinal Morphology in Adult Zebrafish

      Spectral Domain Optical Coherence Tomography: An In Vivo Imaging Protocol for Assessing Retinal Morphology in Adult Zebrafish

      The present study outlines a protocol for examining retinal structure in zebrafish, a popular model organism for ocular studies, using spectral domain optical coherence tomography (SD-OCT). We demonstrate how this live imaging modality can be used to obtain high quality images of several retinal features, including the optic nerve, retinal vasculature, and the cone photoreceptor mosaic. Retinal histology sections were obtained from imaged fish for comparison with SD-OCT cross-sectional B-scans. Voronoi domain analysis was used to assess cone photoreceptor packing regularity at 3, 6, and 12 months. SD-OCT is an effective in vivo technique for studying the adult zebrafish retina ...

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    24. Phase variance optical coherence microscopy for label-free imaging of the developing vasculature in zebrafish embryos

      Phase variance optical coherence microscopy for label-free imaging of the developing vasculature in zebrafish embryos

      A phase variance optical coherence microscope (pvOCM) has been created to image blood flow in the microvasculature of zebrafish embryos, without the use of exogenous labels. The pvOCM imaging system has axial and lateral resolutions of 2.8    μ m 2.8  μm in tissue and imaging depth of more than 100    μ m 100  μm . Images of 2 to 5 days postfertilization zebrafish embryos identified the detailed anatomical structure based on OCM intensity contrast. Phase variance contrast offered visualization of blood flow in the arteries, veins, and capillaries. The pvOCM images of the vasculature were confirmed by direct comparisons with fluorescence ...

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    1-24 of 258 1 2 3 4 ... 9 10 11 »
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