The purpose of this study was to evaluate whether treatment time and concentration of these reagents have an effect on the resulting gliding resistance. other IACUC-approved projects. The superficial aspect of the paratenon was carefully removed, as recommended clinically when extrasynovial tendons are used for tendon grafting.9,10 Care was taken not to injure the tendon surface. The second digit was dissected from each hind paw. The proximal and middle phalanges were obtained by disarticulating the metacarpophalangeal joint and distal interphalangeal joint. The A2 pulley was carefully preserved. The flexor digitorum superficialis was cut just at the proximal edge of the proximal phalanx to ensure that only the FDP would glide [Fig. 1(A)]. To simplify the measurement of its interaction with the FDS,11,12 a 1.8-mm Kirschner wire was inserted through the PIP joint to maintain it in an extended position.11,13 Figure 1 The schema of the specimen. The flexor digitorum superficialis was cut at the proximal edge of proximal phalanx to ensure a smooth gliding bed for the FDP. B: Testing apparatus for the measurement of gliding resistance between the tendon and pulley. The … Treatment of the extrasynovial tendon by CD-HA The reaction components included sodium hyaluronate (HA), 95%, >1.5 106 (Acros Organics, Pittsburgh, PA), gelatin (from porcine skin, Sigma Chemical, St. Louis, MO), 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC; Sigma), and 2-(< 0.05) (Fig. 4). However, in groups A30 and A60, the gliding resistance gradually increased over the 1000 cycles of motion. In group B, the gliding resistances of B5, B30, and B60 remained stably low (<0.14 N) up to 1000 cycles (Fig. 5). In group C, C5, and C60 was stably low (<0.15 N) but the gliding resistance of C30 gradually increased to 0.21 N (Fig. 6). Figure 4 Group A: Gliding resistance of PL tendon treated (0.5% HA, 0.25% EDC/NHS) under various times and control. Figure 5 Group B: Gliding resistance of PL tendon treated (0.5% HA, 1% EDC/NHS) Y-33075 under various times and control. Figure 6 Group C: Gliding resistance of PL tendon treated (1% HA, 1% EDC/NHS) under various times and control. There were significant differences in gliding resistance due to treatment time and surface treatment. There was also a significant interaction between the two main effects (Fig. 7) after 1000 cycles. Figure 7 Gliding resistance of PL tendon after treatment at 1000 cycles. There were significant differences in friction due to time and treatment group and the interaction between time and treatment group was significant (< 0.05). DISCUSSION The carbodiimide derivatization, a chemical modification of HA, has been used clinically for many years, usually in the form of prefabricated films. More recently, the use of this reaction Mouse monoclonal to HSPA5 has been investigated reaction must proceed before implantation. After implantation, the reaction may continue, but if the lubricating compound is not sufficiently fixed, motion will remove it prematurely. We have found that in this tendon surface treatment, a lower EDC/NHS concentration requires a longer reaction time for initial fixation, while with higher concentrations of EDC and NHS even a 5-min fixation time is sufficient to improve gliding resistance and to protect from subsequent abrasion with 1000 repetitions of simulated motion. Sun et Y-33075 al. obtained a significantly lower gliding resistance than that noted in previous reports.8 While previous studies had used hyaluronic acid from rooster comb, Sun and coworkers used hyaluronic acid from and added gelatin to the reaction mixture.8,17 However, Sun and coworkers only tested one combination of reagents (1% HA, 0.25% EDC/NHS, 10% gelatin).17 On the basis of the current study, we believe that the concentration of HA and any reactive agents are critical factors in determining the ultimate HA persistence after repetitive motion, and that the effect of the concentration of the EDC and NHS has a more important role than that of the HA in this regard. On the basis of our data, 0.5% HA, 0.25% EDC/NHS, and 10% gelatin (group A), 0.5% HA, 1% EDC/NHS, and 10% gelatin Y-33075 (group B), Y-33075 and 1% HA, 1% NHS/EDC, and 10% gelatin (group C) were the most effective combinations to reduce friction, enhance binding strength, and increase the residual HA on the tendon surface after 1000 flexionCextension cycles may not be relevant to conditions. 1000 cycles is a round number, and the testing could be completed in roughly 20 min. The rate, less than 1 Hz, is in the physiological range. As most postoperative tendon therapy regimens suggest 10 or more hourly repetitions, this number of cycles would be experienced in the critical first week after surgery, when adhesions begin to form.12 Repetitive cycling alters the viscoelasticity of the tendon, may affect the swelling/shrinking or other tendon properties, and could thereby affect our resistance measures. Indeed, we noted changes in the first five cycles which may well represent.