Takashi Okamoto

Nuclear factor kappa B (NF-kappa B) is a transcription factor that is critical for the inducible expression of multiple cellular and viral genes. DNA binding activity is essential for its function. Here, we report that gold compounds, especially aurothioglucose (AuTG), have a strong inhibitory effect on NF-kappa B-DNA binding. Our finding also reveals that Zn2+ is a necessary component of NF-kappa B for its DNA binding activity and that gold ion can efficiently block NF-kappa B-DNA binding, presumably through oxidation of the cysteins associated with zinc. This redox mechanism may provide an explanation for the observed efficacy of gold compounds in the treatment of rheumatoid arthritis.

PURPOSE: Rebamipide increases the amount of mucin-like substances in the stomach. We aimed to determine the effects of rebamipide on the amount of mucin-like substances in the conjunctiva and cornea of N-acetylcysteine-treated eyes. Furthermore, we attempted to evaluate the effects of rebamipide on the wound healing of N-acetylcysteine-treated eyes. METHODS: The model was created by instilling 10% N-acetylcysteine solutions into rabbit eyes. Rebamipide was then applied on the day following the completion of N-acetylcysteine treatment. The amount of mucin-like substances on the conjunctiva and cornea was measured using the Alcian-blue binding method. The degree of damage was evaluated using scores based on the areas and densities of the cornea and conjunctival after staining using a rose Bengal solution under blind conditions. RESULTS: Rebamipide increased the level of mucin-like substances on the conjunctiva of N-acetylcysteine-treated eyes when instilled at concentrations of 0.3% or higher, and 1% rebamipide increased the amount of mucin-like substances covering the cornea. Moreover, 1% rebamipide improved the rose Bengal scores of the cornea and conjunctiva in N-acetylcysteine-treated eyes. CONCLUSIONS: Rebamipide increased mucin-like substances on the cornea and conjunctiva of N-acetylcysteine-treated eyes. In accordance with the mucin-increasing effects, rebamipide improved the rose Bengal scores for the cornea and conjunctiva of N-acetylcysteine-treated eyes. However, the relevance of these findings to dry eyes is unclear because it is not known whether the change in mucus expression in the N-acetylcysteine model is similar to what occurs in aqueous tear deficiency. Consequently, it may be worth trying on an animal model of keratoconjunctivitis sicca.

We investigated the role of ethylene and auxin in regulating the growth and morphology of roots during mechanical impedance by developing a new growing system and using the model plant Arabidopsis (Arabidopsis thaliana). The Arabidopsis seedlings grown horizontally on a dialysis membrane-covered agar plate encountered adequate mechanical impedance as the roots showed characteristic ethylene phenotypes: 2-fold reduction in root growth, increase in root diameter, decrease in cell elongation, and ectopic root hair formation. The root phenotype characterization of various mutants having altered response to ethylene biosynthesis or signaling, the effect of ethylene inhibitors on mechanically impeded roots, and transcription profiling of the ethylene-responsive genes led us to conclude that enhanced ethylene response plays a primary role in changing root morphology and development during mechanical impedance. Further, the differential sensitivity of horizontally and vertically grown roots toward exogenous ethylene suggested that ethylene signaling plays a critical role in enhancing the ethylene response. We subsequently demonstrated that the enhanced ethylene response also affects the auxin response in roots. Taken together, our results provide a new insight into the role of ethylene in changing root morphology during mechanical impedance.