RESULTS: A series of 3-(trimethoxysilyl) propyl methacrylate/N-vinyl pyrrolidone (TMSPM/NVP) xerogels containing different concentration of ethylene glycol dimethacrylate (EGDMA) as crosslinking agent were prepared by bulk polymerization to high conversion using BPO as initiator. The copolymers were characterized by FTIR. The corresponding hydrogels were obtained by swelling the xerogels in deionized water to equilibrium. Addition of EGDMA increases the transparency of xerogels and hydrogels. The minimum amount of EGDMA required to produce a transparent xerogel is 1%. All the Swelling parameters, including water content (EWC), volume fraction of polymer (ϕ2) and weight loss during swelling decrease with increasing EGDMA. Young's and shear modulus (E and G) increase as EGDMA increases. The hydrogels were characterized in terms of modulus cross-linking density (veand vt) and polymer-solvent interaction parameters (χ). Thermal properties include TGA and glass transition temperature (Tg) enhance by adding EGDMA whereas the oxygen permeability (P) of hydrogels decreases as water content decrease.
CONCLUSIONS: This study prepared and studied the properties for new copolymer (TMSPM-co-NVP) contains different amounts of (EGDMA). These copolymers possess new properties with potential use in different biomedical applications. The properties of the prepared hydrogels are fit with the standard properties of materials which should be used for contact lenses.
Materials and Methods: This prospective single-blind study was carried out on a total of 240 patients with tympanic membrane perforation at a tertiary referral center. The subjects underwent primary or revision myringoplasty. Grafting success rate and hearing results were measured and the comparison between the primary and revision groups was drawn.
Results: Grafting success rate was reported as 96.6% (112 out of 116 cases) for myringoplasty, while in revision myringoplasty the success rate of 78.2% (97 out of 124 patients) was achieved (P=0.001). Speech reception threshold was 23.1±9.2 dB and 24.9±13.1 dB in the primary and revision groups, respectively (P>0.05). However, the percentage of air-bone gap on audiometry≤20 dB were 83.8% and 76% in the primary and revision groups, respectively (P=0.26).
Conclusion: The findings of the present study have shown that although grafting success was reported significantly better in myringoplasty (tympanoplasty type 1), compared to that in revision myringoplasty, it did not reveal any superiority over revision tympanoplasty regarding the hearing outcomes. No consensus was achieved due to a great number of controversies in the literature.
Abstract: Platelet microparticles (PMPs) are small membrane fragments released from activated platelets in response to various stimuli. PMPs serve as biomarkers for several diseases and conditions and are useful tools for prognostic, diagnostic, and therapeutic purposes. The objective of our study was to compare the direct effects of ethylenediaminetetraacetic acid (EDTA) and sodium citrate anticoagulants on platelet structure and PMP vesiculation using transmission electron microscopy to visualize the morphologic changes in platelets. Micrographs revealed that platelets in the EDTA-anticoagulated tube manifested with significant morphologic changes and induced PMP vesiculation. On the other hand, the sodium citrate-anticoagulated tube showed a normal platelet structure and minor modifications in some cases, with poor indication of PMP vesiculation. In conclusion, EDTA induced platelet activation and PMP vesiculation and represents a major source of artifacts during the pre-analysis steps of PMP vesiculation.