Antihistamines, H1. Histamine antagonists or antihistamines are drugs that relieve allergy symptoms.Histamine is a chemical used to identify and remove substances that trigger an allergic response. Ã¢ There are four histamine receptors &#40;designated H<sub>1</sub>, H<sub>2</sub>, H<sub>3</sub>, H<sub>4</sub>&#41;.
Water leaks in central air conditioners are almost always caused by a problem with the condensate pan or drain pipes. The most common of those problems is a clogged drain line. When your condensate drain line gets clogged, water backs up and builds up in your pan. With nowhere to go, that water will begin to leak over your drain pan and onto your system and your floor. Another problem that can lead to a water leak is a crack somewhere in the pan or in the drain pipes.
A: Flooded or fluid-filled lungs, or pulmonary edema, occurs when air sacs in the lungs fill with fluid, according to the Mayo Clinic. Causes of pulmonary edema include a weakened left ventricle in the heart, trauma, drowning, high altitude and reactions to drugs or toxins.