2522 Ricin Ricin is a plant toxin found in the castor bean (Ricinus communis). It can cause severe allergic reactions, and exposure to small quantities can be fatal. (L1034) 9009-86-3 64089.974999999846 Either a white powder or a liquid in crystalline form. (L1034) >10 mg/mL Ingestion, injection or inhalation. (L1034) Pure ricin consists of a neutral A chain and an acidic B chain connected by S--S bonds. The A chain is capable of inhibiting protein synthesis which results in its toxic action. The B chain functions as carrier moiety which binds the toxin to the cell surface. Ricin intoxication is proposed to have three main phases: Intravasal RBC aggregation, acute adrenocortical insufficiency and disturbances of carbohydrate metabolism dur to liver damage. Ricin works by penetrating the cells of the body and inhibiting cell protein synthesis. By attaching to a carbohydrate chain on the cell surface, the ricin molecule anchors itself to the cell, is subsequently engulfed and enters the inner parts of the cell where it reacts with the 60S ribosomal subunit and interferes with the normal protein synthesis process of the cell. Without these proteins, cells cannot survive. The severity of the effects of ricin poisoning vary on the means of exposure to the substance. (L1034, A616) The mechanism of metabolism of ricin has not been investigated but presumably consists of proteolysis (L1037). Free toxin may be removed by opsonization via the reticuloendothelial system (primarily the liver and kidneys) or it may be degraded through cellular internalization via the lysosomes. Lysosomes are membrane-enclosed organelles that contain an array of digestive enzymes, including several proteases. LD50: 2.8-8 ug/kg (Intraperitoneal, Mouse) (L1037) LD50: 2.8-8 ug/kg (Intravenous, Mouse) (L1037) 500 ug for an adult human. (L1034) No indication of carcinogenicity to humans (not listed by IARC). Ricin is a plant toxin found in the castor bean (Ricinus communis). Some researchers have speculated about using ricins in the treatment of cancer, as a so-called "magic bullet" to destroy targeted cells. Ricin could be linked to a monoclonal antibody to target malignant cells recognized by the antibody. The United States investigated ricin for its military potential during the First World War. (L1034) Long term organ damage is likely in survivors. Ricin causes severe diarrhea and victims can die of shock. Ingestion results in severe gastroenteritis, often hemorrhagic. Later, victims may become drowsy, confused, irrational, and comatose; convulsions occur. Moreover, peripheral vascular collapse and renal failure may develop. Local inflammatory lesions result from dust in the eyes, nose and throat. (L1034, A614) Ricin irritates the skin and eyes. Inhalation may cause respiratory distress, fever, cough, nausea, tightness in the chest, heavy sweating and pulmonary edema. Ingestion can result in vomiting, diarrhea, severe dehydration, low blood pressure, hallucinations, and seizures. In either case, death may result from respiratory failure or liver, speen, and/or kidney damage. (L1224, L1034) As there is no antidote for ricin, treatment consists of supportive medical care to minimize the effects of the poisoning. This may include respiratory assistance, intravenous fluids, medications to treat conditions such as seizure and low blood pressure, or administering activated charcoal. (L1224, L1034) 2009-07-03T22:06:25Z 2014-12-24T20:25:34Z P02879 Ricin 1BR5 true Exogenous Liquid 1br5_bio_r_500.jpg image/jpeg 46881 2014-10-14T18:12:34Z BSEQ0008418