Large tympanic membrane perforations usually require a surgical tympanoplasty for closure. Reducing surgical costs and risks has encouraged investigators to examine nonsurgical office procedures for healing these perforations. Growth accelerators are the most promising agents. We study here the closure of large acute perforations using weekly applications of 1 mg of 1% hyaluronic acid (HA), 0.4 microg basic fibroblast growth factor (bFGF), or 1.0 microg epidermal growth factor (EGF) directly to the tympanic membranes of the experimental ears. Control ears were treated with 0. 1 mL Vasocidin. Complete closure was obtained in 100% of the ears treated with HA and EGF and 85.7% of those treated with bFGF by day 21, compared with 63.6% of the controls by day 32. Moderate-to-severe ipsilateral and contralateral external canal hypertrophy was noted in 14.2% and 37.5% of the ears treated with bFGF and HA, respectively, but was not seen in ears treated with EGF or in the control group.
Iuring the periodcovered by this contract 21626] the following studies were attempted on muscle, bone and model systems.Measurements of the longitudinal relaxation time Tl' the transverse relaxation time T2 and the self-diffusion coefficient D for water molecules in colloidal suspensions of silica particles (Ludox) showed a temperature dependence essentially like that found for pure water by Simpson and Carr (1).The more interesting result, however, was the small increase in the selfdiffusion coefficient D compared to the pure water value at a given temperature and a smaller activation energy. The results showed that T2 is sensitive to the degree of calcium-activated ATP-ase activity exhibited by myosin, particularly in low ionic strength preparations at pH 9.5.On the other hand, Tl is more sensitive to variations in ambient temperature than to the presence of calcium ions and ATP in solutions. Measurements made on the several fractions obtained from chromatographically purified preparations indicated that T2 depends on the presence or absence of oligonucleotides bound to myosin molecules. Again, Tl was more sensitive to temperature variations. We interpreted the behavior of Tl to mean that the gross viscosity LEGAL NOTICE
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