Electron interaction with DNA constituents in aqueous phase.

Electron driven chemistry of biomolecules in aqueous phase presents the realistic picture to study molecular processes. In this study we have investigated the interactions of electrons with the DNA constituents in their aqueous phase in order to obtain the quantities useful for DNA damage assessment. We have computed the inelastic mean free path (IMFP), mass stopping power (MSP) and absorbed dose (D) for the DNA constituents (Adenine, Cytosine, Guanine, Thymine and Uracil) in the aqueous medium from ionisation threshold to 5000 eV. We have modified complex optical potential formalism to include band gap of the systems to calculate inelastic cross sections which are used to estimate these entities. This is the maiden attempt to report these important quantities for the aqueous DNA constituents. We have compared our results with available data in gas and other phase and have observed explicable accord for IMFP and MSP. Since these are the first results of absorbed dose (D) for these compounds, we have explored present results vis-a-vis dose absorption in water.

Preformed enzymes in mast cell granules and their potential role in allergic rhinitis.

Mast cells not only function as effector cells but also influence nearly every other cell involved in causing allergic rhinitis. Mast cell-derived mediators such as histamine, bradykinin, tryptase, and the arachidonic acid derivatives produce the symptoms of the early-phase reaction of allergic rhinitis and also attract and activate other leukocytes involved in the late-phase reaction. In addition, activated mast cells are known to secrete a number of cytokines, both preformed and newly synthesized, that can modulate T- and B-cell function, propagate the early- and late-phase reactions, and contribute to tissue remodeling. Most currently available therapies work by antagonizing the mediators secreted by mast cells and other leukocytes. With the possible exception of immunotherapy, these therapies do not provide long-term protection against allergic disorders. Exciting new developments in gene-based therapies seem promising in both reducing and reversing the development of allergic rhinitis.