Browsing by Subject "Natural sciences"

Now showing 1 - 3 of 3
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    Compensatory adaptation of parallel motor pathways promotes skilled forelimb recovery after spinal cord injury
    (Elsevier, 2024-11-13) Sheikh, Imran S.; Keefe, Kathleen M.; Sterling, Noelle A.; Junker, Ian P.; Li, Chen; Chen, Jie; Xu, Xiao-Ming; Kirby, Lynn G.; Smith, George M.; Neurology, School of Medicine
    Skilled forelimb patterning is regulated by the corticospinal tract (CST) with support from brainstem regions. When the CST is lesioned, there is a loss of forelimb function; however, if indirect pathways remain intact, rehabilitative training can facilitate recovery. Following spinal cord injury, rehabilitation is thought to enhance the reorganization and plasticity of spared supraspinal-propriospinal circuits, aiding functional recovery. This study focused on the roles of cervical propriospinal interneurons (PNs) and rubrospinal neurons (RNs) in the recovery of reaching and grasping behaviors in rats with bilateral lesions of the CST and dorsal columns at C5. The lesions resulted in a 50% decrease in pellet retrieval, which normalized over four weeks of training. Silencing PNs or RNs after recovery resulted in reduced retrieval success. Notably, silencing both pathways corresponded to greater functional loss, underscoring their parallel contributions to recovery, alongside evidence of CST fiber sprouting in the spinal cord and red nucleus.
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    Extracellular matrix protein composition dynamically changes during murine forelimb development
    (Elsevier, 2024-01-09) Jacobson, Kathryn R.; Saleh, Aya M.; Lipp, Sarah N.; Tian, Chengzhe; Watson, Audrey R.; Luetkemeyer, Callan M.; Ocken, Alexander R.; Spencer, Sabrina L.; Kinzer-Ursem, Tamara L.; Calve, Sarah; Medicine, School of Medicine
    The extracellular matrix (ECM) is an integral part of multicellular organisms, connecting different cell layers and tissue types. During morphogenesis and growth, tissues undergo substantial reorganization. While it is intuitive that the ECM remodels in concert, little is known regarding how matrix composition and organization change during development. Here, we quantified ECM protein dynamics in the murine forelimb during appendicular musculoskeletal morphogenesis (embryonic days 11.5-14.5) using tissue fractionation, bioorthogonal non-canonical amino acid tagging, and mass spectrometry. Our analyses indicated that ECM protein (matrisome) composition in the embryonic forelimb changed as a function of development and growth, was distinct from other developing organs (brain), and was altered in a model of disease (osteogenesis imperfecta murine). Additionally, the tissue distribution for select matrisome was assessed via immunohistochemistry in the wild-type embryonic and postnatal musculoskeletal system. This resource will guide future research investigating the role of the matrisome during complex tissue development.
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    Scientists in the Making: Promoting African American Students’ Interest in Science through Inquiry-based, Culturally Relevant Instruction
    (Clute Institute, 2011) Mutegi, Jomo W.; School of Education
    The low number of African Americans pursuing careers in the natural sciences has been (and continues to be) a concern for science educators. While science educators have sought to explain the science-career decisions of African Americans through research (Hager & Elton, 1971; Lewis, 2003; Lewis & Collins, 2001; Lewis & Connell, 2005; Lewis, Pitts, & Collins, 2002; Maple & Stage, 1991), we have also worked to increase African American representation in science through various intervention programs (Barisa & Holland, 1993; Carmichael & Sevenair, 1991; Hrabowski, 1999; Maton, Hrabowski, & Schmitt, 2000; Tobias, 1992). Unfortunately, the problem has been a resilient one and African Americans (comprising fewer than 2% of practicing, Ph.D.-holding scientists since 1977) continue to be underrepresented in science and science-related careers (National Science Board, 2000).