CARDIFF, Wales, April 23 (UPI) -- Researchers in Wales and England have developed a highly effective asthma drug, and in the process may have uncovered the disorder's root cause. In a recent study, scientists explored the breathing disorder via both mouse and human airway models, using tissue from asthmatic and non-asthmatic people. Their work highlighted the body's calcium sensing receptor (CaSR) as the main culprit in triggering asthma symptoms -- airway narrowing, airway twitchiness and inflammation. Much as the immune system of allergy patients overreacts to pollen or other particulates, the research models showed CaSR went into overdrive when asthmatic...