intermediate definition an intermediate is a substance formed during a middle step of a chemical reaction between reactants and the desired product
The international pictogram for chemicals that are sensitising, mutagenic, carcinogenic or toxic to reproduction. A carcinogen is any substance, radionuclide, or radiation that is an agent directly involved in causing cancer. This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes. Several radioactive substances are considered carcinogens, but their carcinogenic activity is attributed to the radiation, for example gamma rays and alpha particles, which they emit. Common examples of non-radioactive carcinogens are inhaled asbestos, certain dioxins, and tobacco smoke.
Causes of Carcinoid Syndrome. Carcinoid syndrome occurs when you have a carcinoid tumor that is secreting chemicalsâsuch as serotoninâinto your bloodstream. The chemicals cause your blood vessels to dilate, or open up. Most carcinoid tumors do not secrete chemicals that cause this condition. If a carcinoid tumor does secrete chemicals, the liver often neutralizes them before they can spread through your body. Typically, carcinoid syndrome is a sign that your cancer has spread to your liver or lungs. According to the National Cancer Institute, 58 to 64 percent of people with carcinoid tumors of the small intestine already have metastatic disease in the lymph nodes or liver. (NCI). The cause of these tumors is unknown. However, carcinoid tumors are most likely to form in your gastrointestinal tractâwhich includes your appendix, stomach, small intestine, colon, and rectumâor in your lungs.