1. Articles in category: Developmental Biology

    1-24 of 196 1 2 3 4 5 6 7 8 9 »
    1. Rotational imaging optical coherence tomography for full-body mouse embryonic imaging

      Rotational imaging optical coherence tomography for full-body mouse embryonic imaging

      Optical coherence tomography (OCT) has been widely used to study mammalian embryonic development with the advantages of high spatial and temporal resolutions and without the need for any contrast enhancement probes. However, the limited imaging depth of traditional OCT might prohibit visualization of the full embryonic body. To overcome this limitation, we have developed a new methodology to enhance the imaging range of OCT in embryonic day (E) 9.5 and 10.5 mouse embryos using rotational imaging. Rotational imaging OCT (RI-OCT) enables full-body imaging of mouse embryos by performing multiangle imaging. A series of postprocessing procedures was performed on ...

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    2. Classifying murine glomerulonephritis using optical coherence tomography and optical coherence elastography

      Classifying murine glomerulonephritis using optical coherence tomography and optical coherence elastography

      Elastic-wave propagation in mouse healthy and nephritic kidneys. Acute glomerulonephritis caused by antiglomerular basement membrane marked by high mortality. The primary reason for this is delayed diagnosis via blood examination, urine analysis, tissue biopsy, or ultrasound and X-ray computed tomography imaging. Blood, urine, and tissue-based diagnoses can be time consuming, while ultrasound and CT imaging have relatively low spatial resolution, with reduced sensitivity. Optical coherence tomography is a noninvasive and high-resolution imaging technique that provides superior spatial resolution (micrometer scale) as compared to ultrasound and CT. Changes in tissue properties can be detected based on the optical metrics analyzed from ...

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

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

      University of Houston Receives a 2016 NIH Grant for $424,849 for Optical Coherence Tomography to Study Effect of Poly-Drug Exposure of Fetal Brain Development. The principal investigator is Kirill 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 to ...

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    4. In vivo three-dimensional characterization of the adult zebrafish brain using a 1325 nm spectral-domain optical coherence tomography system with the 27 frame/s video rate

      In vivo three-dimensional characterization of the adult zebrafish brain using a 1325 nm spectral-domain optical coherence tomography system with the 27 frame/s video rate

      In this study, a spectral-domain optical coherence tomography (SD-OCT) system was used for noninvasive imaging of the adult zebrafish brain. Based on a 1325 nm light source and two high-speed galvo mirrors, our SD-OCT system can offer a large field of view of brain morphology with high resolution (12 μm axial and 13 μm lateral) at video rate (27 frame/s). In vivo imaging of both the control and injured brain was performed using adult zebrafish model. The recovered results revealed that olfactory bulb, optic commissure, telencephalon, tectum opticum, cerebellum, medulla, preglomerular complex and posterior tuberculum could be clearly identified ...

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    5. In vivo assessment of wall strain in embryonic chick heart by spectral domain optical coherence tomography

      In vivo assessment of wall strain in embryonic chick heart by spectral domain optical coherence tomography

      The ability to measure in vivo wall strain in embryonic hearts is important for fully understanding the mechanisms of cardiac development. Optical coherence tomography (OCT) is a powerful tool for the three-dimensional imaging of complex myocardial activities in early-stage embryonic hearts with high spatial and temporal resolutions. We describe a method to analyze periodic deformations of myocardial walls and evaluate in vivo myocardial wall strains with a high-speed spectral domain OCT system. We perform four-dimensional scanning on the outflow tract (OFT) of chick embryonic hearts and determine a special cross-section in which the OFT can be approximated as an annulus ...

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    6. Laminar microvascular transit time distribution in the mouse somatosensory cortex revealed by Dynamic Contrast Optical Coherence Tomography

      Laminar microvascular transit time distribution in the mouse somatosensory cortex revealed by Dynamic Contrast Optical Coherence Tomography

      The transit time distribution of blood through the cerebral microvasculature both constrains oxygen delivery and governs the kinetics of neuroimaging signals such as blood-oxygen-level-dependent functional Magnetic Resonance Imaging (BOLD fMRI). However, in spite of its importance, capillary transit time distribution has been challenging to quantify comprehensively and efficiently at the microscopic level. Here, we introduce a method, called Dynamic Contrast Optical Coherence Tomography (DyC-OCT), based on dynamic cross-sectional OCT imaging of an intravascular tracer as it passes through the field-of-view. Quantitative transit time metrics are derived from temporal analysis of the dynamic scattering signal, closely related to tracer concentration. Since ...

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    7. Blood flow through the embryonic heart outflow tract during cardiac looping in HH13–HH18 chicken embryos

      Blood flow through the embryonic heart outflow tract during cardiac looping in HH13–HH18 chicken embryos

      Blood flow is inherently linked to embryonic cardiac development, as haemodynamic forces exerted by flow stimulate mechanotransduction mechanisms that modulate cardiac growth and remodelling. This study evaluated blood flow in the embryonic heart outflow tract (OFT) during normal development at each stage between HH13 and HH18 in chicken embryos, in order to characterize changes in haemodynamic conditions during critical cardiac looping transformations. Two-dimensional optical coherence tomography was used to simultaneously acquire both structural and Doppler flow images, in order to extract blood flow velocity and structural information and estimate haemodynamic measures. From HH13 to HH18, peak blood flow rate increased ...

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    8. Direct four-dimensional structural and functional imaging of cardiovascular dynamics in mouse embryos with 1.5  MHz optical coherence tomography

      Direct four-dimensional structural and functional imaging of cardiovascular dynamics in mouse embryos with 1.5  MHz optical coherence tomography

      High-resolution three-dimensional (3D) imaging of cardiovascular dynamics in mouse embryos is greatly desired to study mammalian congenital cardiac defects. Here, we demonstrate direct four-dimensional (4D) imaging of the cardiovascular structure and function in live mouse embryos at a ∼ 43     Hz volume rate using an optical coherence tomography (OCT) system with a ∼ 1.5     MHz Fourier domain mode-locking swept laser source. Combining ultrafast OCT imaging with live mouse embryo culture protocols, 3D volumes of the embryo are directly and continuously acquired over time for a cardiodynamics analysis without the application of any synchronization algorithms. We present the time-resolved measurements of the ...

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    9. Optogenetic pacing in Drosophila melanogaster

      Optogenetic pacing in Drosophila melanogaster

      Electrical stimulation is currently the gold standard for cardiac pacing. However, it is invasive and nonspecific for cardiac tissues. We recently developed a noninvasive cardiac pacing technique using optogenetic tools, which are widely used in neuroscience. Optogenetic pacing of the heart provides high spatial and temporal precisions, is specific for cardiac tissues, avoids artifacts associated with electrical stimulation, and therefore promises to be a powerful tool in basic cardiac research. We demonstrated optogenetic control of heart rhythm in a well-established model organism, Drosophila melanogaster . We developed transgenic flies expressing a light-gated cation channel, channelrhodopsin-2 (ChR2), specifically in their hearts and ...

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    10. 4D subject-specific inverse modeling of the chick embryonic heart outflow tract hemodynamics

      4D subject-specific inverse modeling of the chick embryonic heart outflow tract hemodynamics

      Blood flow plays a critical role in regulating embryonic cardiac growth and development, with altered flow leading to congenital heart disease. Progress in the field, however, is hindered by a lack of quantification of hemodynamic conditions in the developing heart. In this study, we present a methodology to quantify blood flow dynamics in the embryonic heart using subject-specific computational fluid dynamics (CFD) models. While the methodology is general, we focused on a model of the chick embryonic heart outflow tract (OFT), which distally connects the heart to the arterial system, and is the region of origin of many congenital cardiac ...

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    11. A Circadian Clock Gene, Cry, Affects Heart Morphogenesis and Function in Drosophila as Revealed by Optical Coherence Microscopy

      A Circadian Clock Gene, Cry, Affects Heart Morphogenesis and Function in Drosophila as Revealed by Optical Coherence Microscopy

      Circadian rhythms are endogenous, entrainable oscillations of physical, mental and behavioural processes in response to local environmental cues such as daylight, which are present in the living beings, including humans. Circadian rhythms have been related to cardiovascular function and pathology. However, the role that circadian clock genes play in heart development and function in a whole animal in vivo are poorly understood. The Drosophila cryptochrome (dCry) is a circadian clock gene that encodes a major component of the circadian clock negative feedback loop. Compared to the embryonic stage, the relative expression levels of dCry showed a significant increase (>100-fold) in ...

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    12. Label-free characterization of vitrification-induced morphology changes in single-cell embryos with full-field optical coherence tomography

      Label-free characterization of vitrification-induced morphology changes in single-cell embryos with full-field optical coherence tomography

      Vitrification is an increasingly popular method of embryo cryopreservation that is used in assisted reproductive technology. Although vitrification has high post-thaw survival rates compared to other freezing techniques, its long-term effects on embryo development are still poorly understood. We demonstrate an application of full-field optical coherence tomography (FF-OCT) to visualize the effects of vitrification on live single-cell (2 pronuclear) mouse embryos without harmful labels. Using FF-OCT, we observed that vitrification causes a significant increase in the aggregation of structures within the embryo cytoplasm, consistent with reports in literature based on fluorescence techniques. We quantify the degree of aggregation with an ...

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    13. Internal physiology of live krill revealed using new aquaria techniques and mixed optical microscopy and optical coherence tomography (OCT) imaging techniques

      Internal physiology of live krill revealed using new aquaria techniques and mixed optical microscopy and optical coherence tomography (OCT) imaging techniques

      The accurate observation of physiological changes on in vivo samples of important animal species such as Euphausia superba (Antarctic krill) is an important goal in helping to understand how environmental changes can affect animal development. Using a custom made ‘krill trap’, live un-anaesthetized krill were confined for seven hours, during which three hours of optical imaging were obtained and no subsequent ill effects observed. The trap enabled two imaging methods to be employed: optical coherence tomography (OCT) and microscopy. OCT enabled internal structure and tissues to be imaged to a depth of approximately 2 mm and resolution of approximately 12 ...

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    14. 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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    15. 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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    16. 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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    17. 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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    18. 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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    19. 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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    20. 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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    21. 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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    22. 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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    23. 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
    24. 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
    1-24 of 196 1 2 3 4 5 6 7 8 9 »
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