The Experts below are selected from a list of 27 Experts worldwide ranked by ideXlab platform

Jonathan I Leckenby - One of the best experts on this subject based on the ideXlab platform.

  • imaging peripheral Nerve regeneration a new technique for 3d visualization of axonal behavior
    Journal of Surgical Research, 2019
    Co-Authors: Jonathan I Leckenby, Miranda A Chacon, A O Grobbelaar, Jeff W Lichtman
    Abstract:

    Abstract Background Peripheral Nerve assessment has traditionally been studied through histological and immunological staining techniques in a limited cross-sectional modality, making detailed analysis difficult. A new application of serial section electron microscopy is presented to overcome these limitations. Methods Direct Nerve repairs were performed on the Posterior Auricular Nerve of transgenic YFP-H mice. Six weeks postoperatively the Nerves were imaged using confocal fluorescent microscopy then excised and embedded in resin. Resin blocks were sequentially sectioned at 100 nm, and sections were serially imaged with an electron microscope. Images were aligned and autosegmented to allow for 3D reconstruction. Results Basic morphometry and axonal counts were fully automated. Using full 3D reconstructions, the relationships between the axons, the Nodes of Ranvier, and Schwann cells could be fully appreciated. Interactions of individual axons with their surrounding environment could be visualized and explored in a virtual three-dimensional space. Conclusions Serial section electron microscopy allows the detailed pathway of the regenerating axon to be visualized in a 3D virtual space in comparison to isolated individual traditional histological techniques. Fully automated histo-morphometry can now give accurate axonal counts, provide information regarding the quality of Nerve regeneration, and reveal the cell-to-cell interaction at a super-resolution scale. It is possible to fully visualize and “fly-through” the Nerve to help understand the behavior of a regenerating axon within its environment. This technique provides future opportunities to evaluate the effect different treatment modalities have on the neuroregenerative potential and help us understand the impact different surgical techniques have when treating Nerve injuries.

  • development of the interscutularis model as an outcome measure for facial Nerve surgery
    Annals of Anatomy-anatomischer Anzeiger, 2019
    Co-Authors: Jonathan I Leckenby, Miranda A Chacon, K J Rolfe, Jeff W Lichtman, A O Grobbelaar
    Abstract:

    Abstract Introduction Animal models for the study of facial paralysis have been well developed, but concern has arisen regarding the accuracy of eye closure and whisker movement as outcome measures due to new data regarding interconnectivity between facial Nerve branches and autonomic innervation. The Posterior Auricular Nerve (PAN) is an isolated branch of the facial Nerve which has been confirmed as the sole motor innervat or of the interscutularis muscle. This study was designed to develop a model for facial Nerve palsy utilizing the PAN and interscutularis muscle. Methods A custom-made automated video capture system was built into a poly methyl methacrylate cage using a high definition monochrome digital camera and image sensor to record the animal as it drank from a water feeder. A copper floor pad and copper collar around the water feeder were connected to an electrical circuit for automatic saving of the video recording 10 s prior to and 30 s following the drinking event. A pre-operative baseline recording of ear movement during drinking was captured. Female YFP-16 mice at 6 weeks were assigned to sham (Sh, n = 5), Nerve excision (Ex, n = 10), or Nerve crush (Cr, n = 10) groups with all interventions performed on the right PAN. Sh mice were irrigated with 10 ml normal saline as were the Ex and Cr mice following operative intervention. In Ex mice, a 3 mm section of the PAN was sharply excised and Nerve gap was confirmed with fluorescent microscopy. In Cr mice, the PAN was crushed 3 mm from the origin of the facial Nerve trunk with size 5 jeweler’s forceps for two periods of 20 s. Post-operative video recordings were collected on post-operative days (POD) 1, 10, 20, and 30. To determine the change in ear movement, the right ear was graphically compared to the left control side. Results Sh animals exhibited a statistically significant reduction in ear movement at POD01 compared to other POD recordings (p  Conclusion The results show that significant differences were demonstrated between the experimental groups and that significant changes within the crush group were identifiable making this an acceptable model to develop as an accurate outcome measure following rodent facial Nerve surgery.

A O Grobbelaar - One of the best experts on this subject based on the ideXlab platform.

  • imaging peripheral Nerve regeneration a new technique for 3d visualization of axonal behavior
    Journal of Surgical Research, 2019
    Co-Authors: Jonathan I Leckenby, Miranda A Chacon, A O Grobbelaar, Jeff W Lichtman
    Abstract:

    Abstract Background Peripheral Nerve assessment has traditionally been studied through histological and immunological staining techniques in a limited cross-sectional modality, making detailed analysis difficult. A new application of serial section electron microscopy is presented to overcome these limitations. Methods Direct Nerve repairs were performed on the Posterior Auricular Nerve of transgenic YFP-H mice. Six weeks postoperatively the Nerves were imaged using confocal fluorescent microscopy then excised and embedded in resin. Resin blocks were sequentially sectioned at 100 nm, and sections were serially imaged with an electron microscope. Images were aligned and autosegmented to allow for 3D reconstruction. Results Basic morphometry and axonal counts were fully automated. Using full 3D reconstructions, the relationships between the axons, the Nodes of Ranvier, and Schwann cells could be fully appreciated. Interactions of individual axons with their surrounding environment could be visualized and explored in a virtual three-dimensional space. Conclusions Serial section electron microscopy allows the detailed pathway of the regenerating axon to be visualized in a 3D virtual space in comparison to isolated individual traditional histological techniques. Fully automated histo-morphometry can now give accurate axonal counts, provide information regarding the quality of Nerve regeneration, and reveal the cell-to-cell interaction at a super-resolution scale. It is possible to fully visualize and “fly-through” the Nerve to help understand the behavior of a regenerating axon within its environment. This technique provides future opportunities to evaluate the effect different treatment modalities have on the neuroregenerative potential and help us understand the impact different surgical techniques have when treating Nerve injuries.

  • development of the interscutularis model as an outcome measure for facial Nerve surgery
    Annals of Anatomy-anatomischer Anzeiger, 2019
    Co-Authors: Jonathan I Leckenby, Miranda A Chacon, K J Rolfe, Jeff W Lichtman, A O Grobbelaar
    Abstract:

    Abstract Introduction Animal models for the study of facial paralysis have been well developed, but concern has arisen regarding the accuracy of eye closure and whisker movement as outcome measures due to new data regarding interconnectivity between facial Nerve branches and autonomic innervation. The Posterior Auricular Nerve (PAN) is an isolated branch of the facial Nerve which has been confirmed as the sole motor innervat or of the interscutularis muscle. This study was designed to develop a model for facial Nerve palsy utilizing the PAN and interscutularis muscle. Methods A custom-made automated video capture system was built into a poly methyl methacrylate cage using a high definition monochrome digital camera and image sensor to record the animal as it drank from a water feeder. A copper floor pad and copper collar around the water feeder were connected to an electrical circuit for automatic saving of the video recording 10 s prior to and 30 s following the drinking event. A pre-operative baseline recording of ear movement during drinking was captured. Female YFP-16 mice at 6 weeks were assigned to sham (Sh, n = 5), Nerve excision (Ex, n = 10), or Nerve crush (Cr, n = 10) groups with all interventions performed on the right PAN. Sh mice were irrigated with 10 ml normal saline as were the Ex and Cr mice following operative intervention. In Ex mice, a 3 mm section of the PAN was sharply excised and Nerve gap was confirmed with fluorescent microscopy. In Cr mice, the PAN was crushed 3 mm from the origin of the facial Nerve trunk with size 5 jeweler’s forceps for two periods of 20 s. Post-operative video recordings were collected on post-operative days (POD) 1, 10, 20, and 30. To determine the change in ear movement, the right ear was graphically compared to the left control side. Results Sh animals exhibited a statistically significant reduction in ear movement at POD01 compared to other POD recordings (p  Conclusion The results show that significant differences were demonstrated between the experimental groups and that significant changes within the crush group were identifiable making this an acceptable model to develop as an accurate outcome measure following rodent facial Nerve surgery.

Jeff W Lichtman - One of the best experts on this subject based on the ideXlab platform.

  • imaging peripheral Nerve regeneration a new technique for 3d visualization of axonal behavior
    Journal of Surgical Research, 2019
    Co-Authors: Jonathan I Leckenby, Miranda A Chacon, A O Grobbelaar, Jeff W Lichtman
    Abstract:

    Abstract Background Peripheral Nerve assessment has traditionally been studied through histological and immunological staining techniques in a limited cross-sectional modality, making detailed analysis difficult. A new application of serial section electron microscopy is presented to overcome these limitations. Methods Direct Nerve repairs were performed on the Posterior Auricular Nerve of transgenic YFP-H mice. Six weeks postoperatively the Nerves were imaged using confocal fluorescent microscopy then excised and embedded in resin. Resin blocks were sequentially sectioned at 100 nm, and sections were serially imaged with an electron microscope. Images were aligned and autosegmented to allow for 3D reconstruction. Results Basic morphometry and axonal counts were fully automated. Using full 3D reconstructions, the relationships between the axons, the Nodes of Ranvier, and Schwann cells could be fully appreciated. Interactions of individual axons with their surrounding environment could be visualized and explored in a virtual three-dimensional space. Conclusions Serial section electron microscopy allows the detailed pathway of the regenerating axon to be visualized in a 3D virtual space in comparison to isolated individual traditional histological techniques. Fully automated histo-morphometry can now give accurate axonal counts, provide information regarding the quality of Nerve regeneration, and reveal the cell-to-cell interaction at a super-resolution scale. It is possible to fully visualize and “fly-through” the Nerve to help understand the behavior of a regenerating axon within its environment. This technique provides future opportunities to evaluate the effect different treatment modalities have on the neuroregenerative potential and help us understand the impact different surgical techniques have when treating Nerve injuries.

  • development of the interscutularis model as an outcome measure for facial Nerve surgery
    Annals of Anatomy-anatomischer Anzeiger, 2019
    Co-Authors: Jonathan I Leckenby, Miranda A Chacon, K J Rolfe, Jeff W Lichtman, A O Grobbelaar
    Abstract:

    Abstract Introduction Animal models for the study of facial paralysis have been well developed, but concern has arisen regarding the accuracy of eye closure and whisker movement as outcome measures due to new data regarding interconnectivity between facial Nerve branches and autonomic innervation. The Posterior Auricular Nerve (PAN) is an isolated branch of the facial Nerve which has been confirmed as the sole motor innervat or of the interscutularis muscle. This study was designed to develop a model for facial Nerve palsy utilizing the PAN and interscutularis muscle. Methods A custom-made automated video capture system was built into a poly methyl methacrylate cage using a high definition monochrome digital camera and image sensor to record the animal as it drank from a water feeder. A copper floor pad and copper collar around the water feeder were connected to an electrical circuit for automatic saving of the video recording 10 s prior to and 30 s following the drinking event. A pre-operative baseline recording of ear movement during drinking was captured. Female YFP-16 mice at 6 weeks were assigned to sham (Sh, n = 5), Nerve excision (Ex, n = 10), or Nerve crush (Cr, n = 10) groups with all interventions performed on the right PAN. Sh mice were irrigated with 10 ml normal saline as were the Ex and Cr mice following operative intervention. In Ex mice, a 3 mm section of the PAN was sharply excised and Nerve gap was confirmed with fluorescent microscopy. In Cr mice, the PAN was crushed 3 mm from the origin of the facial Nerve trunk with size 5 jeweler’s forceps for two periods of 20 s. Post-operative video recordings were collected on post-operative days (POD) 1, 10, 20, and 30. To determine the change in ear movement, the right ear was graphically compared to the left control side. Results Sh animals exhibited a statistically significant reduction in ear movement at POD01 compared to other POD recordings (p  Conclusion The results show that significant differences were demonstrated between the experimental groups and that significant changes within the crush group were identifiable making this an acceptable model to develop as an accurate outcome measure following rodent facial Nerve surgery.

Miranda A Chacon - One of the best experts on this subject based on the ideXlab platform.

  • imaging peripheral Nerve regeneration a new technique for 3d visualization of axonal behavior
    Journal of Surgical Research, 2019
    Co-Authors: Jonathan I Leckenby, Miranda A Chacon, A O Grobbelaar, Jeff W Lichtman
    Abstract:

    Abstract Background Peripheral Nerve assessment has traditionally been studied through histological and immunological staining techniques in a limited cross-sectional modality, making detailed analysis difficult. A new application of serial section electron microscopy is presented to overcome these limitations. Methods Direct Nerve repairs were performed on the Posterior Auricular Nerve of transgenic YFP-H mice. Six weeks postoperatively the Nerves were imaged using confocal fluorescent microscopy then excised and embedded in resin. Resin blocks were sequentially sectioned at 100 nm, and sections were serially imaged with an electron microscope. Images were aligned and autosegmented to allow for 3D reconstruction. Results Basic morphometry and axonal counts were fully automated. Using full 3D reconstructions, the relationships between the axons, the Nodes of Ranvier, and Schwann cells could be fully appreciated. Interactions of individual axons with their surrounding environment could be visualized and explored in a virtual three-dimensional space. Conclusions Serial section electron microscopy allows the detailed pathway of the regenerating axon to be visualized in a 3D virtual space in comparison to isolated individual traditional histological techniques. Fully automated histo-morphometry can now give accurate axonal counts, provide information regarding the quality of Nerve regeneration, and reveal the cell-to-cell interaction at a super-resolution scale. It is possible to fully visualize and “fly-through” the Nerve to help understand the behavior of a regenerating axon within its environment. This technique provides future opportunities to evaluate the effect different treatment modalities have on the neuroregenerative potential and help us understand the impact different surgical techniques have when treating Nerve injuries.

  • development of the interscutularis model as an outcome measure for facial Nerve surgery
    Annals of Anatomy-anatomischer Anzeiger, 2019
    Co-Authors: Jonathan I Leckenby, Miranda A Chacon, K J Rolfe, Jeff W Lichtman, A O Grobbelaar
    Abstract:

    Abstract Introduction Animal models for the study of facial paralysis have been well developed, but concern has arisen regarding the accuracy of eye closure and whisker movement as outcome measures due to new data regarding interconnectivity between facial Nerve branches and autonomic innervation. The Posterior Auricular Nerve (PAN) is an isolated branch of the facial Nerve which has been confirmed as the sole motor innervat or of the interscutularis muscle. This study was designed to develop a model for facial Nerve palsy utilizing the PAN and interscutularis muscle. Methods A custom-made automated video capture system was built into a poly methyl methacrylate cage using a high definition monochrome digital camera and image sensor to record the animal as it drank from a water feeder. A copper floor pad and copper collar around the water feeder were connected to an electrical circuit for automatic saving of the video recording 10 s prior to and 30 s following the drinking event. A pre-operative baseline recording of ear movement during drinking was captured. Female YFP-16 mice at 6 weeks were assigned to sham (Sh, n = 5), Nerve excision (Ex, n = 10), or Nerve crush (Cr, n = 10) groups with all interventions performed on the right PAN. Sh mice were irrigated with 10 ml normal saline as were the Ex and Cr mice following operative intervention. In Ex mice, a 3 mm section of the PAN was sharply excised and Nerve gap was confirmed with fluorescent microscopy. In Cr mice, the PAN was crushed 3 mm from the origin of the facial Nerve trunk with size 5 jeweler’s forceps for two periods of 20 s. Post-operative video recordings were collected on post-operative days (POD) 1, 10, 20, and 30. To determine the change in ear movement, the right ear was graphically compared to the left control side. Results Sh animals exhibited a statistically significant reduction in ear movement at POD01 compared to other POD recordings (p  Conclusion The results show that significant differences were demonstrated between the experimental groups and that significant changes within the crush group were identifiable making this an acceptable model to develop as an accurate outcome measure following rodent facial Nerve surgery.

Eric E. Turner - One of the best experts on this subject based on the ideXlab platform.

  • Hmx1 is required for the normal development of somatosensory neurons in the geniculate ganglion.
    Developmental biology, 2012
    Co-Authors: Lely A. Quina, Lynne Tempest, Yun Wei A Hsu, Timothy C. Cox, Eric E. Turner
    Abstract:

    Hmx1 is a variant homeodomain transcription factor expressed in the developing sensory nervous system, retina, and craniofacial mesenchyme. Recently, mutations at the Hmx1 locus have been linked to craniofacial defects in humans, rats, and mice, but its role in nervous system development is largely unknown. Here we show that Hmx1 is expressed in a subset of sensory neurons in the cranial and dorsal root ganglia which does not correspond to any specific sensory modality. Sensory neurons in the dorsal root and trigeminal ganglia of Hmx1dm/dm mouse embryos have no detectable Hmx1 protein, yet they undergo neurogenesis and express sensory subtype markers normally, demonstrating that Hmx1 is not globally required for the specification of sensory neurons from neural crest precursors. Loss of Hmx1 expression has no obvious effect on the early development of the trigeminal (V), superior (IX/X), or dorsal root ganglia neurons in which it is expressed, but results in marked defects in the geniculate (VII) ganglion. Hmx1dm/dm mouse embryos possess only a vestigial Posterior Auricular Nerve, and general somatosensory neurons in the geniculate ganglion are greatly reduced by mid-gestation. Although Hmx1 is expressed in geniculate neurons prior to cell cycle exit, it does not appear to be required for neurogenesis, and the loss of geniculate neurons is likely to be the result of increased cell death. Fate mapping of neural crest-derived tissues indicates that Hmx1-expressing somatosensory neurons at different axial levels may be derived from either the neural crest or the neurogenic placodes.