Antihistamine drugs act by blocking the action of histamine on nerve endings. Cromoglicate-based drugs (sodium cromoglicate, nedocromil) block a calcium channel essential for mast cell degranulation, stabilizing the cell and preventing release of histamine and related mediators. Leukotriene antagonists (such as montelukast and zafirlukast) block the action of leukotriene mediators, IgE antibody (omalizumab) also inhibits the binding of free IgE to the high-affinity IgE receptor (FcεRI) on the surface of mast cells and basophils, and are being used increasingly in allergic diseases.
The bottom 2" pipe is the full 21' length, and the top 1-1/2" pipe is about 17' long to give the total of 36' with the 2' overlap. The drawing to the left (not to scale) shows the base and some of the details of the assembly. The base is made of another 21' piece of 2" pipe cut in half to make a 10-1/2' long base unit. The pipes are spaced a little more than one pipe diameter apart and secured by welding 3/16" X 2" steel strap between them. The mast pivots on a 3/8 X 8" bolt at the base midpoint just above ground level (dashed rectangle). This leaves about 5' of base both above and below ground.
An important adaptor protein activated by the Syk phosphorylation step is the linker for activation of T cells (LAT). LAT can be modified by phosphorylation to create novel binding sites.  Phospholipase C gamma (PLCγ) becomes phosphorylated once bound to LAT, and is then used to catalyze phosphatidylinositol bisphosphate breakdown to yield inositol trisphosphate (IP3) and diacyglycerol (DAG). IP3 elevates calcium levels, and DAG activates protein kinase C (PKC). This is not the only way that PKC is made. The tyrosine kinase FYN phosphorylates Grb2-associated-binding protein 2 (Gab2), which binds to phosphoinositide 3-kinase , which activates PKC. PKC leads to the activation of myosin light-chain phosphorylation granule movements, which disassembles the actin–myosin complexes to allow granules to come into contact with the plasma membrane.  The mast cell granule can now fuse with the plasma membrane. Soluble N-ethylmaleimide sensitive fusion attachment protein receptor SNARE complex mediates this process. Different SNARE proteins interact to form different complexes that catalyze fusion. Rab3 guanosine triphosphatases and Rab-associated kinases and phosphatases regulate granule membrane fusion in resting mast cells.