Browsing by Subject "Musculoskeletal"
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Item Unknown Examining the roles of resident non-myogenic mesenchymal cell populations in skeletal muscle development and injury(2022) Leinroth , AbigailThe success of muscle development and regeneration requires cooperation from both myogenic and their supportive niche cells. The muscular niche is complex. At the cellular level it is composed of a broad number of cell types including: endothelial vessels, nerve and nerve-supporting cells, resident immune populations, and a heterogenous group of non-myogenic mesenchymal cells. The non-myogenic mesenchymal cells include pericytes, vascular smooth muscle cells, interstitial tenocyte-like cells, and fibro-adipogenic progenitors (FAPs). Like all members of the muscular niche, this fraction is vital to muscle development and regeneration. Despite their importance to muscle development, regeneration, and homeostasis, detailed identities within non-myogenic mesenchymal cells remain elusive. By understanding the distinct makeup of this population, we can provide a foundation to examine their important regulatory roles in the processes of muscle development, homeostasis, injury and disease.
This thesis utilizes single cell RNA sequencing to establish the populations of non-myogenic mesenchymal cells in developing muscle. Our analysis identified pericytes, vascular smooth muscle cells, and tenocyte-like cell populations while uncovering a new level of heterogeneity in FAPs that not previously appreciated. Despite classical understanding of FAPs as one group, this work found that FAPs were sub-divided into five distinct populations, which compose two trajectories spawning from a common progenitor. This thesis defines the functional differences of each FAP population through a series of experiments including: fluorescence activated cell sorting of various FAP groups, studying their spatial localization on immunofluorescence, and testing the response of different FAPs to multiple injury and disease models.
Separate preliminary work examines the impact of NOTCH signaling in FAPs and the broader non-myogenic mesenchymal cell groups. These studies discovered that NOTCH signaling in the non-myogenic mesenchymal group, but not FAPs specifically, regulates muscular growth and intramuscular adipogenesis. Altogether this thesis advances our understanding of the identity, and role of, non-myogenic mesenchymal cells, in muscle development and regeneration.
Item Unknown Foot for Thought: Identifying Causes of Foot and Leg Pain in Rural Madagascar to Improve Musculoskeletal Health(2018-04-25) Tasnim, NoorIncidence of musculoskeletal health disorders is increasing in Madagascar. Foot pain in the Malagasy may be related to daily occupational activities or foot shape and lack of footwear. Our study tests hypotheses concerning the cause of foot pain in male and female Malagasy populations and its effects on gait kinematics. The study was conducted in Mandena, Madagascar. We obtained 89 participants’ height, mass, and age from a related study (n male = 41, n female = 48). We collected self-report data on daily activity and foot and lower limb pain. A modified Revised Foot Function Index (FFI-R) assessed pain, difficulty, and limitation of activities because of reported foot pain (total score = 27). We quantified ten standard foot shape measures. Participants walked across a force platform at self-selected speeds while being videorecorded at 120 fps. Females reported higher FFI-R scores (p = 0.029), spending more hours on their feet (p = 0.0184), and had larger BMIs (p = 0.0001) than males. Strong linear relationships were examined between participants’ self-selected speed and force curve peaks and loading rates. No significant differences were found in force curve parameters between participants with foot/ankle/knee pain and lack thereof. Males showed higher values of force curve parameters and steeper slopes when relating velocity to the same parameters. The higher foot pain and lower force peaks in females may be related to the combination of higher BMI, small feet relative to BMI, and the amount of time they are on their feet. Results suggest that a combination of BMI, foot size, and occupational factors influence foot pain in this community leading to long term injury and limitations on work. These results will help guide future interventions that promote engagement in leisure/work activities.Item Unknown Musculoskeletal effects and injury risk in collegiate Indian classical and ballet dancers(2016-06-07) Prakash, RoshniDancers of all forms often engage in aesthetic yet challenging movements. Their training, choreography, and performances require strength, stamina, flexibility, grace, passion, and emotion. Ballet and Bharatanatyam (an Indian classical dance form) dancers utilize two movements in each of their dance forms that are similar—a half-sitting pose and a full-sitting pose, both requiring external rotation of the legs and bending at the knee joints. The purpose of this study was to examine and compare the biomechanics of joint reaction forces and knee angles in both styles of dance for these particular poses. The study included nine female ballet dancers and seven female Bharatanatyam dancers. Hamstring and gastrocnemius flexibility were measured for each dancer. Knee angles, vertical peak forces, and moments were determined for dancers at the lowest point of their bending positions. Mann-Whitney U tests found significant differences in hamstring flexibility, right gastrocnemius flexibility, and knee angles for the full-sitting poses between ballet and Bharatanatyam dancers. No significant difference was found in the vertical peak forces as a ratio to total body weight and moments between the two styles of dance. Further research can be done to more directly assess a difference in injury risk between the ballet and Bharatanatyam dancers.