scholarly journals The Neuromodulator Adenosine Regulates Oligodendrocyte Migration at Motor Exit Point Transition Zones

Cell Reports ◽  
2019 ◽  
Vol 27 (1) ◽  
pp. 115-128.e5 ◽  
Author(s):  
Laura Fontenas ◽  
Taylor G. Welsh ◽  
Melanie Piller ◽  
Patricia Coughenour ◽  
Avni V. Gandhi ◽  
...  
Keyword(s):  
Exit Point ◽  
Transition Zones

scholarly journals Radial glia inhibit peripheral glial infiltration into the spinal cord at motor exit point transition zones

Glia ◽  
2016 ◽  
Vol 64 (7) ◽  
pp. 1138-1153 ◽  
Author(s):  
Cody J. Smith ◽  
Kimberly Johnson ◽  
Taylor G. Welsh ◽  
Michael J. F. Barresi ◽  
Sarah Kucenas
Keyword(s):  
Spinal Cord ◽  
Radial Glia ◽  
Exit Point ◽  
Transition Zones

scholarly journals Spinal cord precursors utilize neural crest cell mechanisms to generate hybrid peripheral myelinating glia

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Laura Fontenas ◽  
Sarah Kucenas
Keyword(s):  
Spinal Cord ◽  
Schwann Cells ◽  
Neural Tube ◽  
Neural Crest Cell ◽  
Exit Point ◽  
Transition Zones ◽  
Glial Development ◽  
Myelinating Glia ◽  
Peripheral Motor ◽  
Crest Cell

During development, oligodendrocytes and Schwann cells myelinate central and peripheral nervous system axons, respectively, while motor exit point (MEP) glia are neural tube-derived, peripheral glia that myelinate axonal territory between these populations at MEP transition zones. From which specific neural tube precursors MEP glia are specified, and how they exit the neural tube to migrate onto peripheral motor axons, remain largely unknown. Here, using zebrafish, we found that MEP glia arise from lateral floor plate precursors and require foxd3 to delaminate and exit the spinal cord. Additionally, we show that similar to Schwann cells, MEP glial development depends on axonally derived neuregulin1. Finally, our data demonstrate that overexpressing axonal cues is sufficient to generate additional MEP glia in the spinal cord. Overall, these studies provide new insight into how a novel population of hybrid, peripheral myelinating glia are generated from neural tube precursors and migrate into the periphery.

scholarly journals Spinal cord precursors utilize neural crest cell mechanisms to generate hybrid peripheral myelinating glia

2020 ◽  
Author(s):  
Laura Fontenas ◽  
Sarah Kucenas
Keyword(s):  
Spinal Cord ◽  
Schwann Cells ◽  
Neural Tube ◽  
Neural Crest Cell ◽  
Exit Point ◽  
Transition Zones ◽  
Glial Development ◽  
Myelinating Glia ◽  
Peripheral Motor ◽  
Crest Cell

AbstractDuring development, oligodendrocytes and Schwann cells myelinate central and peripheral nervous system axons, respectively, while motor exit point (MEP) glia are neural tube-derived, peripheral glia that myelinate axonal territory between these populations at MEP transition zones. From which specific neural tube precursors MEP glia are specified, and how they exit the neural tube to migrate onto peripheral motor axons, remain largely unknown. Here, using zebrafish, we found that MEP glia arise from lateral floor plate precursors and require foxd3 to delaminate and exit the spinal cord. Additionally, we show that similar to Schwann cells, MEP glial development depends on axonally-derived neuregulin1. Finally, our data demonstrate that overexpressing axonal cues is sufficient to generate additional MEP glia in the spinal cord. Overall, these studies provide new insight into how a novel population of hybrid, peripheral myelinating glia are generated from neural tube precursors and migrate into the periphery.

Drivers of Small-Scale Diptera Distribution in Aquatic-Terrestrial Transition Zones of Spring Fens

Wetlands ◽  
2019 ◽  
Vol 40 (2) ◽  
pp. 235-247
Author(s):  
Vendula Polášková ◽  
Jana Schenková ◽  
Martina Bílková ◽  
Martina Poláková ◽  
Vanda Šorfová ◽  
...  
Keyword(s):  
Small Scale ◽  
Transition Zones ◽  
Spring Fens

Phosphate immobilisation dynamics and interaction with arsenic sorption at redox transition zones in floodplain aquifers: Insights from the Red River Delta, Vietnam

2021 ◽  
Vol 411 ◽  
pp. 125128
Author(s):  
Harald Neidhardt ◽  
Sebastian Rudischer ◽  
Elisabeth Eiche ◽  
Magnus Schneider ◽  
Emiliano Stopelli ◽  
...  
Keyword(s):  
River Delta ◽  
Red River ◽  
Red River Delta ◽  
Transition Zones ◽  
Redox Transition

scholarly journals Effect of oblique headless compression screw fixation for metacarpal shaft fracture: a biomechanical in vitro study

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Yung-Cheng Chiu ◽  
Tsung-Yu Ho ◽  
Yen-Nien Ting ◽  
Ming-Tzu Tsai ◽  
Heng-Li Huang ◽  
...  
Keyword(s):  
Articular Cartilage ◽  
Screw Fixation ◽  
Shaft Fracture ◽  
Metacarpal Bone ◽  
Entry Point ◽  
Fixation Method ◽  
Exit Point ◽  
Compression Screw ◽  
Headless Compression Screw ◽  
Metacarpal Shaft

Abstract Background Metacarpal shaft fracture is a common fracture in hand trauma injuries. Surgical intervention is indicated when fractures are unstable or involve considerable displacement. Current fixation options include Kirschner wire, bone plates, and intramedullary headless screws. Common complications include joint stiffness, tendon irritation, implant loosening, and cartilage damage. Objective We propose a modified fixation approach using headless compression screws to treat transverse or short-oblique metacarpal shaft fracture. Materials and methods We used a saw blade to model transverse metacarpal neck fractures in 28 fresh porcine metacarpals, which were then treated with the following four fixation methods: (1) locked plate with five locked bicortical screws (LP group), (2) regular plate with five bicortical screws (RP group), (3) two Kirschner wires (K group), and (4) a headless compression screw (HC group). In the HC group, we proposed a novel fixation model in which the screw trajectory was oblique to the long axis of the metacarpal bone. The entry point of the screw was in the dorsum of the metacarpal neck, and the exit point was in the volar cortex of the supracondylar region; thus, the screw did not damage the articular cartilage. The specimens were tested using a modified three-point bending test on a material testing system. The maximum fracture forces and stiffness values of the four fixation types were determined by observing the force–displacement curves. Finally, the Kruskal–Wallis test was adopted to process the data, and the exact Wilcoxon rank sum test with Bonferroni adjustment was performed to conduct paired comparisons among the groups. Results The maximum fracture forces (median ± interquartile range [IQR]) of the LP, RP, HC, and K groups were 173.0 ± 81.0, 156.0 ± 117.9, 60.4 ± 21.0, and 51.8 ± 60.7 N, respectively. In addition, the stiffness values (median ± IQR) of the LP, HC, RP, and K groups were 29.6 ± 3.0, 23.1 ± 5.2, 22.6 ± 2.8, and 14.7 ± 5.6 N/mm, respectively. Conclusion Headless compression screw fixation provides fixation strength similar to locked and regular plates for the fixation of metacarpal shaft fractures. The headless screw was inserted obliquely to the long axis of the metacarpal bone. The entry point of the screw was in the dorsum of the metacarpal neck, and the exit point was in the volar cortex of the supracondylar region; therefore the articular cartilage iatrogenic injury can be avoidable. This modified fixation method may prevent tendon irritation and joint cartilage violation caused by plating and intramedullary headless screw fixation.

Characterizing Reactive Iron Mineral Coatings in Redox Transition Zones

2020 ◽  
Vol 4 (12) ◽  
pp. 2337-2346
Author(s):  
Han Hua ◽  
Xin Yin ◽  
James A. Dyer ◽  
Richard Landis ◽  
Lisa Axe
Keyword(s):  
Transition Zones ◽  
Redox Transition ◽  
Iron Mineral ◽  
Reactive Iron ◽  
Mineral Coatings

scholarly journals Modeling of relative permeabilities including dynamic wettability transition zones

2021 ◽  
pp. 108556
Author(s):  
Abay Molla Kassa ◽  
Sarah E. Gasda ◽  
Kundan Kumar ◽  
Florin A. Radu
Keyword(s):  
Relative Permeabilities ◽  
Transition Zones
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