Recurrent mass hysteria in schoolchildren in Western Nepal.

AIM: The aim was to study the clinical presentation and factors contributing to "recurrent mass hysteria" among rural schoolgoing children. MATERIALS AND METHODS: A visit to a school in a remote hilly district of Puythan, Nepal, was carried out to assess students experiencing mass dissociative/conversion symptoms over a short period of time. There was a second incidence of "mass hysteria" on the day of visit. Regular follow-up of these students was done telephonically for the next 1 year. RESULTS: The total number of child victim of "mass hysteria" was 47, with majority of them being girl students. Historically, at least two more attacks of "mass hysteria" were noted in the schoolchildren in the preceding years. Follow-up study revealed no further attacks of similar "mass attacks" over the following 1 year. CONCLUSION: Supporting, assuring, counseling, and educating these children, their parents and teachers and conducting public awareness programs are the mainstay of treatment of mass hysteria.

Fluorescence quenching of coumarins by halide ions.

Fluorescence quenching of 4-methyl-7-methoxy coumarin (1) and 4-methyl-5-ethoxy-7-methoxy coumarin (2) in aqueous solutions have been studied at different concentrations of halide ions (Cl-, Br-, I-), at room temperature approximately 20 degrees C. It is observed that the fluorescence intensity of both the coumarin compounds (1 and 2) decrease with increase in the concentration of Br- and I- ions but remains almost constant in case of Cl- ion. It is observed that the quenching due to halide ions proceeds via both a diffusional and static quenching processes. The rate constants for diffusional as well as static component of quenching process have been calculated using modified Stern-Volmer relation. It is further observed, that I- ion has very high quenching ability than Br- ion and Cl) ion almost behaves as a non-quencher. It is explained in terms of the sphere of action model by showing that the value of radius of sphere of action of the halide quencher is greater than the sum of the radii of the respective coumarin and quencher. Further, pattern of the quenching ability of the halide quenchers is found to be as I- > Br- > Cl- and interestingly this is in the same order as of their ionization energy. Finally, the present quenching process has been attributed to the electron transfer resulting between colliding species.