Rubber: A high-molecular-weight polymeric elastomer derived from the milk juice (LATEX) of HEVEA brasiliensis and other trees and plants. It is a substance that can be stretched at room temperature to at least twice its original length and after releasing the stress, retract rapidly, and recover its original dimensions fully.Hevea: A plant genus of the family EUPHORBIACEAE, order Euphorbiales, subclass Rosidae. Commercial natural RUBBER is mainly obtained from Hevea brasiliensis but also from some other plants.Rubber Dams: Sheets of latex rubber punched and placed over the teeth during dental procedures to isolate the field of operation from the rest of the oral cavity (Jablonski; Illustrated Dictionary of Dentistry, 1982). Rubber dams are useful in preventing the swallowing of instruments or restorations during dental work.Latex: A milky, product excreted from the latex canals of a variety of plant species that contain cauotchouc. Latex is composed of 25-35% caoutchouc, 60-75% water, 2% protein, 2% resin, 1.5% sugar & 1% ash. RUBBER is made by the removal of water from latex.(From Concise Encyclopedia Biochemistry and Molecular Biology, 3rd ed). Hevein proteins are responsible for LATEX HYPERSENSITIVITY. Latexes are used as inert vehicles to carry antibodies or antigens in LATEX FIXATION TESTS.Silicone Elastomers: Polymers of silicone that are formed by crosslinking and treatment with amorphous silica to increase strength. They have properties similar to vulcanized natural rubber, in that they stretch under tension, retract rapidly, and fully recover to their original dimensions upon release. They are used in the encapsulation of surgical membranes and implants.Latex Hypersensitivity: Allergic reaction to products containing processed natural rubber latex such as rubber gloves, condoms, catheters, dental dams, balloons, and sporting equipment. Both T-cell mediated (HYPERSENSITIVITY, DELAYED) and IgE antibody-mediated (HYPERSENSITIVITY, IMMEDIATE) allergic responses are possible. Delayed hypersensitivity results from exposure to antioxidants present in the rubber; immediate hypersensitivity results from exposure to a latex protein.Taraxacum: A plant genus of the family ASTERACEAE. Members contain chicoric and chlorogenic acids and germacrane- and eudesmane-type SESQUITERPENES.Gloves, Protective: Coverings for the hands, usually with separations for the fingers, made of various materials, for protection against infections, toxic substances, extremes of hot and cold, radiations, water immersion, etc. The gloves may be worn by patients, care givers, housewives, laboratory and industrial workers, police, etc.Hemiterpenes: The five-carbon building blocks of TERPENES that derive from MEVALONIC ACID or deoxyxylulose phosphate.Hemorrhoids: Swollen veins in the lower part of the RECTUM or ANUS. Hemorrhoids can be inside the anus (internal), under the skin around the anus (external), or protruding from inside to outside of the anus. People with hemorrhoids may or may not exhibit symptoms which include bleeding, itching, and pain.Euphorbiaceae: The spurge family of flowering plants, in the order Euphorbiales, contains some 7,500 species in 275 genera. The family consists of annual and perennial herbs and woody shrubs or trees.Dimethylallyltranstransferase: An enzyme that, in the pathway of cholesterol biosynthesis, catalyzes the condensation of isopentenyl pyrophosphate and dimethylallylpyrophosphate to yield pyrophosphate and geranylpyrophosphate. The enzyme then catalyzes the condensation of the latter compound with another molecule of isopentenyl pyrophosphate to yield pyrophosphate and farnesylpyrophosphate. EC 2.5.1.1.Nevus, Blue: Usually a benign tumor, that commonly presents as a solitary blue nodule with spindled MELANOCYTES covered by smooth SKIN. Several variants have been identified, one variant being malignant. The blue color is caused by large, densely packed melanocytes deep in the DERMIS of the nevus. In CHILDREN, they usually occur on the BUTTOCKS and LUMBOSACRAL REGION and are referred to as cellular blue nevi. Malignant blue nevi are more commonly found on the SCALP.Chemical Industry: The aggregate enterprise of manufacturing and technically producing chemicals. (From Random House Unabridged Dictionary, 2d ed)Illusions: The misinterpretation of a real external, sensory experience.Gloves, Surgical: Gloves, usually rubber, worn by surgeons, examining physicians, dentists, and other health personnel for the mutual protection of personnel and patient.