Changes in Gait Characteristics Following a Concussion

Introduction: Recent literature has suggested that gait could potentially provide clinicians with a reliable way to determine if an athlete has sufficiently recovered from a concussion in order to return to participation. The Balance Error Scoring System has typically been used to determine if static and postural control have returned to baseline measurements. It has yet to be determined the level of gait recovery within 24 hours of sustaining a concussion (CD1), on the day the concussed athlete returns to BESS baseline (BBD), or the day they finally return to play (RTPD). Objective: The purpose of this study was to compare a concussed athlete\u27s gait to non-concussed athletes and normal controls, on specific days of their recovery process. Methods: In this study, 45 subjects were divided into groups; 15 concussed intercollegiate athletes (CONCs), 15 non-concussed teammates (NONCs), and 15 normal controls (NORMs) who did not participate in an intercollegiate sport. The NONCs were matched according to sport and gender, and the NORMs were matched to gender of the CONCs. The subjects walked on the GAITRite® walkway, where gait velocity, cadence, step length, step width, and double leg support times were calculated. The NONCs and CONCs walked the same number of days as their CONC match, until the CONC returned to participation. Results: Gait velocity showed significant group differences at CD1 (F= 3.670, p=.034), whereby CONCs had a mean gait velocity significantly less than the NORMs (1.21 + 0.16 m/s and 1.34 + 0.09 m/s respectively, p=.036). There were significant main effects for gait velocity, step length, step width, and double leg support times. Most of the subjects increased their gait velocity and step length (F=18.940 and p\u3c.001, F=16.542 and p\u3c.001), respectively) and decreased their double leg support times (F=14.395 and p\u3c.001) between CD1 and BBD. Subjects from CD1 to RTPD showed increases in gait velocity and step length (F= 11.901 and p=.001, F=10.553 and p=.002, respectively), and decreases in step width and double leg support times (F=11.976 and p=.001, and F=10.583, p=.002, respectively). However, there were no significant differences for gait velocity, cadence, step length, step width, or double leg support times between CONC and NONC, CONC and NORM, or NONC and NORM from CD1 to BBD, BBD to RTPD, or from CD1 to RTPD. Conclusion: These findings indicate that a concussed athlete shows slower gait velocity initially after a concussion at CD1, possibly indicating a conservative gait strategy that develops into normal gait patterns as BBD and RTPD occur. However, cadence, step length, step width, and double leg support times during single task walking may not be good indicators on whether an athlete has recovered their postural control. Therefore, it is recommended that a variety of concussion testing tools, including postural control measurements such as gait, be used to make a proper assessment of when the athlete may return to participation

Myosin folding boosts solubility in cardiac muscle sarcomeres.

The polymerization of myosin molecules into thick filaments in muscle sarcomeres is essential for cardiac contractility, with the attenuation of interactions between the heads of myosin molecules within the filaments being proposed to result in hypercontractility, as observed in hypertrophic cardiomyopathy (HCM). However, experimental evidence demonstrates that the structure of these giant macromolecular complexes is highly dynamic, with molecules exchanging between the filaments and a pool of soluble molecules on the minute timescale. Therefore, we sought to test the hypothesis that the enhancement of interactions between the heads of myosin molecules within thick filaments limits the mobility of myosin by taking advantage of mavacamten, a small molecule approved for the treatment of HCM. Myosin molecules were labeled in vivo with a green fluorescent protein (GFP) and imaged in intact hearts using multiphoton microscopy. Treatment of the intact hearts with mavacamten resulted in an unexpected > 5-fold enhancement in GFP-myosin mobility within the sarcomere. In vitro biochemical assays suggested that mavacamten enhanced the mobility of GFP-myosin by increasing the solubility of myosin molecules, through the stabilization of a compact/folded conformation of the molecules, once disassociated from the thick filaments. These findings provide alternative insight into the mechanisms by which molecules exchange into and out of thick filaments and have implications for how mavacamten may affect cardiac contractility

Integrating Evidence-Based Practices into Public Relations Education

Public relations continue to play an essential and changing role in society, requiring the regular reassessment of the education of future public relations practitioners. Academics and practitioners often differ in how they view the public relations field, how they define the discipline, and how they view the major pedagogical approaches. This paper explores the impact of integrating three different perspectives in public relations education, including practitioner perspective, client perspective, and the evidence-based perspective. Results from students’ reaction papers and an online questionnaire suggest that integrating an evidence-based approach improves the competence and clarity of communications counsel provided by aspiring practitioners

Early structural remodeling and deuterium oxide-derived protein metabolic responses to eccentric and concentric loading in human skeletal muscle

We recently reported that the greatest distinguishing feature between eccentric (ECC) and concentric (CON) muscle loading lays in architectural adaptations: ECC favors increases in fascicle length (Lf), associated with distal vastus lateralis muscle (VL) hypertrophy, and CON increases in pennation angle (PA). Here, we explored the interactions between structural and morphological remodeling, assessed by ultrasound and dual x‐ray absorptiometry (DXA), and long‐term muscle protein synthesis (MPS), evaluated by deuterium oxide (D2O) tracing technique. Ten young males (23 ± 4 years) performed unilateral resistance exercise training (RET) three times/week for 4 weeks; thus, one‐leg trained concentrically while the contralateral performed ECC exercise only at 80% of either CON or ECC one repetition maximum (1RM). Subjects consumed an initial bolus of D2O (150 mL), while a 25‐mL dose was thereafter provided every 8 days. Muscle biopsies from VL midbelly (MID) and distal myotendinous junction (MTJ) were collected at 0 and 4‐weeks. MPS was then quantified via GC–pyrolysis–IRMS over the 4‐week training period. Expectedly, ECC and CON RET resulted in similar increases in VL muscle thickness (MT) (7.5% vs. 8.4%, respectively) and thigh lean mass (DXA) (2.3% vs. 3%, respectively), albeit through distinct remodeling: Lf increasing more after ECC (5%) versus CON (2%) and PA increasing after CON (7% vs. 3%). MPS did not differ between contractile modes or biopsy sites (MID‐ECC: 1.42 vs. MID‐CON: 1.4% day−1; MTJ‐ECC: 1.38 vs. MTJ‐CON: 1.39% day−1). Muscle thickness at MID site increased similarly following ECC and CON RET, reflecting a tendency for a contractile mode‐independent correlation between MPS and MT (P = 0.07; R2 = 0.18). We conclude that, unlike MT, distinct structural remodeling responses to ECC or CON are not reflected in MPS; the molecular mechanisms of distinct protein deposition, and/or the role of protein breakdown in mediating these responses remain to be defined

Measures of student success in a college bridge program: a case study

In 1975, scholars Alexander Astin and Vincent Tinto independently developed theories of student persistence that are still applicable today. Much of their work focused on student integration into university life and how developing a strong bond with the social and academic opportunities universities offer help cement a student's tie to their school. Summer bridge programs are an effective way to prepare high school students to transition to university life and develop such a bond. Much research has been done on the positive effects of a bridge program aimed at specific populations who can benefit from an early intervention in their college careers, but what about those that are open to all students? This longitudinal quantitative study focused on one such program to discover if it provided a step up for students in terms of academic success as measured by improved retention, graduation rates, and cumulative grade point average (GPA). Post hoc data were collected for 7 years of program participants and initially summarized to understand the demographics and differences between bridge program participants and the general population. Next the data were analyzed through statistical tests to see if participation could predict retention, graduation rates and GPA. Results showed that the bridge program did improve both retention and GPA, but graduation rate data were mixed. Further research is recommended to determine if graduation rates lag due to the lack of time (7 years only covers a few cohorts for 4- and 6-year graduation rates) or other factors. Additional research is recommended to understand how underserved groups fare in this model and whether targeting is a more effective means for recruitment

The application of 2H2O to measure skeletal muscle protein synthesis

Skeletal muscle protein synthesis has generally been determined by the precursor:product labeling approach using labeled amino acids (e.g., [13C]leucine or [13C]-, [15N]-, or [2H]phenylalanine) as the tracers. Although reliable for determining rates of protein synthesis, this methodological approach requires experiments to be conducted in a controlled environment, and as a result, has limited our understanding of muscle protein renewal under free-living conditions over extended periods of time (i.e., integrative/cumulative assessments). An alternative tracer, 2H2O, has been successfully used to measure rates of muscle protein synthesis in mice, rats, fish and humans. Moreover, perturbations such as feeding and exercise have been included in these measurements without exclusion of common environmental and biological factors. In this review, we discuss the principle behind using 2H2O to measure muscle protein synthesis and highlight recent investigations that have examined the effects of feeding and exercise. The framework provided in this review should assist muscle biologists in designing experiments that advance our understanding of conditions in which anabolism is altered (e.g., exercise, feeding, growth, debilitating and metabolic pathologies)

A potential role for muscle in glucose homeostasis: in vivo kinetic studies in glycogen storage disease type 1a and fructose-1,6-bisphosphatase deficiency

A potential role for muscle in glucose homeostasis was recently suggested based on characterization of extrahepatic and extrarenal glucose-6-phosphatase (glucose-6-phosphatase-beta). To study the role of extrahepatic tissue in glucose homeostasis during fasting glucose kinetics were studied in two patients with a deficient hepatic and renal glycogenolysis and/or gluconeogenesis. Endogenous glucose production (EGP), glycogenolysis (GGL), and gluconeogenesis (GNG) were quantified with stable isotopes in a patient with glycogen storage disease type 1a (GSD-1a) and a patient with fructose-1,6-bisphosphatase (FBPase) deficiency. The [6,6-H-2(2)]glucose dilution method in combination with the deuterated water method was used during individualized fasting tests. Both patients became hypoglycemic after 2.5 and 14.5 h fasting, respectively. At that time, the patient with GSD-1a had EGP 3.84 mu mol/kg per min (30% of normal EGP after an overnight fast), GGL 3.09 mu mol/kg per min, and GNG 0.75 mu mol/kg per min. The patient with FBPase deficiency had EGP 8.53 mu mol/kg per min (62% of normal EGP after an overnight fast), GGL 6.89 mu mol/kg per min GGL, and GNG 1.64 mu mol/kg per min. EGP was severely hampered in both patients, resulting in hypoglycemia. However, despite defective hepatic and renal GNG in both disorders and defective hepatic GGL in GSD-1a, both patients were still able to produce glucose via both pathways. As all necessary enzymes of these pathways have now been functionally detected in muscle, a contribution of muscle to EGP during fasting via both GGL as well as GNG is suggeste