Background: Myasthenic crisis is the most serious life-threatening event in generalized myasthenia gravis (MG) patients. The objective of this study was to assess the long-term impact of thymectomy on rate and severity of these attacks in Iranian patients.

Background: Dental caries is still a major public health problem. The use of fluoride is one of the most effective ways to prevent tooth decay. Objective: The purpose of this research was to investigate the effectiveness of fluoride entrapped in chitosan nanoparticles in vivo. Methods: Sodium fluoride was loaded in chitosan via ionic gelation of tripolyphosphate nanoparticles. Characterization of nanoparticles was investigated by using the zeta potential, size of particles, loading capacities, encapsulation efficiency, and Fourier Transforms Infrared Spectroscopy. Chitosan/ fluoride nanoparticles were fabricated by a method of fluoride/chitosan cross-linking with tripolyphosphate. Results: The size of nanoparticles was 219 nm. According to the zeta potential results, by adding sodium fluoride to chitosan/tripolyphosphate nanoparticles reducing the number of positive charges of chitosan, the result was diminished zeta potential from +30.8 mV to +14.9 mV. The optimum drug loading and percentage of entrapment efficiency were 70% and 30% respectively. Fourier transform infrared spectroscopy confirmed linked among tripolyphosphate, chitosan and fluoride nanoparticles. In vitro characterization of nanoparticles demonstrated higher fluoride uptake ability and smooth releasing profile. Conclusion: It is suggested that fluoride/chitosan nanoparticles synthesized in our study may be a promising means of delivering fluoride for the early prevention of tooth decay.

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