Absence of Bilateral Differences in Child Baseball Players with Throwing-related Pain

The aim of this study was to assess whether side-to-side differences in morphology and function of the upper limbs in 11-12 year-old male baseball players with throwing-related pain (n=14) were more pronounced than that of age-matched healthy untrained subjects (n=16). Baseball players 1) had played baseball≥4.5 h·wk^-1 for ≥ 4 years and (2) suffered from moderate-intensity (3-6 points on 10-point questionnaire scale) throwing-related pain in the shoulder or elbow in at least 2 training sessions within the past month. The range of motion (ROM), function and structure of the elbows and shoulders were assessed using goniometry, isokinetic dynamometry and ultrasonography. While the ROM and eccentric external peak torque of internal shoulder rotation were lower, the thickness of the supraspinatus tendon, the ulnar collateral ligament and articular cartilage of the humeral head were larger in baseball players than controls. There were, however, no significant side-to-side differences in any parameter in either group. In conclusion, it is unlikely that side-to-side differences in shoulder and upper limb structure and function contributed to the throwing-related pain in young baseball players, but low shoulder eccentric external peak torque and range of internal rotation may predispose to throwing-related pain.

Cholesterol-based tethers and markers for model membranes investigation

A series of new bifunctional cholesterol compounds for tethered bilayer membrane (tBLM) systems were synthesized and tested. The compounds containing cyclic disulfide group may be used as molecular anchors for phospholipid bilayers. Anchoring occurs through the insertion of the cholesterol moiety into the hydrophobic slab of the phospholipid layer, while the surface density of anchor molecules may be adjusted using disulfides terminated spacers. Five ethylene oxide segments between the disulfide group and the cholesteryl provide hydration of the layer separating solid support and model membrane. Another group of cholesterol derivatives described in this work contains either fluorescence probe or electroactive functional groups. We demonstrated the practical utility of these compounds for visualization of cholesterol extraction from and loading to tBLMs. We demonstrated that electroactive group containing cholesterol derivatives can be reconstituted either into vesicles or tBLMs. In both cases an electrochemical signal can be generated on electrodes from these probes. In general, the newly synthesized compound may be utilized in a variety of applications involving tethered bilayer systems and vesicles.