Category: Developmental Biology

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 ...

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 ...

PURPOSE. These experiments assessed the ability of spectral domain optical coherence tomography (SD-OCT) to accurately represent the structural organization of the adult zebrafish retina and reveal the dynamic morphological changes during either light-induced damage and regeneration of photoreceptors or ouabain-induced inner retinal damage. METHODS. Retinas of control dark-adapted adult albino zebrafish were compared to retinas subjected to 24 hours of constant intense light and recovered for up to 8 weeks or ouabain-damaged retinas that recovered for up to 3 weeks. Images were captured and the measurements of retinal morphology were made by the Spectral Domain Optical Coherence Tomography (SD-OCT), and ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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.

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 ...

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 ...

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 ...

New imaging technologies have revolutionized the study of developmental biology. Where researchers once struggled to connect events at static timepoints, imaging tools now offer the ability to visualize the dynamic form and function of molecules, cells, tissues, and whole embryos throughout the entire developmental process. Imaging in Developmental Biology: A Laboratory Manual, a new volume in Cold Spring Harbor Laboratory Press’ Imaging series, presents a comprehensive set of essential visualization methods. The manual features primers on live imaging of a variety of standard model organisms including C. elegans, Drosophila, zebrafish, Xenopus, avian species, and mouse. Further techniques are organized by ...