March 15, 2013

Melissa Ellis ‘13Hamline UniversityBiology Senior SeminarAbstract:Sarcospan: A Potential Therapy for Duchenne Muscular Dystrophy

Muscular Dystrophy is group of inherited disorders that result in muscle weakness, decrease in muscle mass, and loss of muscle tissue. There are six different types of muscular dystrophy, though Duchenne muscular dystrophy (DMD) is of great importance as it affects only male children and leads to death by the age of 25. DMD is the result of the loss of dystrophin within the dystrophin-glycoprotein complex (DGC) on the surface of muscle cells. A component of the DGC that is of interest is sarcospan as its overexpression leads to an increase in dystrophin and utrophin. Peter et al. show that sarcospan (SSPN), a unique tetraspanin-like component of the DGC, ameliorates muscular dystrophy in dystrophin deficient mdx mice. SSPN stabilizes the sarcolemma by increasing levels of the utrophin – glycoprotein complex (UGC) at the extrasynaptic membrane to compensate for the loss of dystrophin. Utrophin is normally restricted to the neuromuscular junction, where it replaces dystrophin to form a functionally analogous complex. SSPN directly interacts with the UGC and functions to stabilize utrophin protein without increasing utrophin transcription. These findings reveal the importance of protein stability in the prevention of muscular dystrophy and may impact the future design of therapeutics for muscular dystrophies.

Carly Braun '13Hamline University

Biology Senior Seminar

Abstract:

The Effect of Dumbbells Versus Resistance Bands on Upper Body Strength Gains in College Females

Although resistance bands and dumbbells are commonly used in resistance training programs, little research has directly compared the strength gains produced by these two modalities. The purpose of this study was to compare the effects of a resistance band-based and dumbbell-based resistance training program on upper body strength gains in college-aged females. Methods: Informed consent was obtained for 48 participants; 40 participants completed the 7-week resistance training program consisting of three upper body exercises (lateral arm raises, upright rows, and triceps kickbacks) using either resistance bands or dumbbells. An indirectly-estimated one-repetition maximum (estimated 1-RM) of the seated back press was used to measure strength gains, and was conducted prior to starting the program and at the end of every week. Results and Discussion: The dumbbell group increased their estimated 1-RM strength by 14.2 ± 9.23 lbs. while the resistance band group increased by 15.2 ± 6.08 lbs. An independent T-test revealed no detectable difference (p>.05) between the mean strength gains of the two modality groups (95% CI = -5.96, 3.99), suggesting that these two modalities do not differ in their contribution to strength gains when used in a resistance training program. Conclusion: Resistance bands and dumbbells do not differ in their contribution to upper body strength gains in college-aged females when used in a resistance training program.