discovered the causative mutation in humans only after similar mutations had first been described in pigs.Horses also develop malignant hyperthermia. A causative mutated allele, ryanodine receptor 1 gene (RyR1) at nucleotide C7360G, generating a R2454G amino acid substitution. has been identified in the American Quarter Horse and breeds with Quarter Horse ancestry, inherited as an autosomal dominant. It can be caused by overwork, anesthesia, or stress. In dogs, its inheritance is autosomal recessive.An MH mouse has been constructed, bearing the R163C mutation prevalent in humans. These mice display signs similar to human MH patients, including sensitivity to halothane (increased respiration, body temperature, and death). Blockade of RYR1 by dantrolene prevents adverse reaction to halothane in these mice, as with humans. Muscle from these mice also shows increased K+-induced depolarization and an increased caffeine sensitivity. Diagnosis
During an attack
The earliest signs may include: masseter muscle contracture following administration of succinylcholine, a rise in end-tidal carbon dioxide concentration (despite increased minute ventilation), unexplained tachycardia, and muscle rigidity. Despite the name, elevation of body temperature is often a late sign, but may appear early in severe cases. Respiratory acidosis is universally present and many patients have developed metabolic acidosis at the time of diagnosis. A fast rate of breathing (in a spontaneously breathing patient), cyanosis, hypertension, abnormal heart rhythms, and high blood potassium may also be seen. Core body temperatures should be measured in any patient undergoing general anesthesia longer than 30 minutes. Malignant hyperthermia is diagnosed on clinical grounds, but various laboratory investigations may prove confirmatory.
Vaseline () is an American brand of petroleum jelly-based products owned by transnational company Unilever. Products include plain petroleum jelly and a selection of skin creams, soaps, lotions, cleansers, and deodorants. In many languages, the word "Vaseline" is used as generic for petroleum jelly; in Portugal, the Unilever products are called Vaselina, and in Brazil and some Spanish-speaking countries, the Unilever products are called Vasenol. History
In 1859, Robert Chesebrough, a chemist who formerly clarified kerosene from the oil of sperm whales, traveled to the oil fields in Titusville, Pennsylvania to research what new materials might be created from this new fuel. There he learned of a residue called rod wax that had to be periodically removed from oil rig pumps. The oil workers had been using the substance to heal cuts and burns. Chesebrough took samples of the rod wax back to Brooklyn, extracted the usable petroleum jelly, and began manufacturing a medicinal product he called Vaseline.The first known reference to the name Vaseline was by Chesebrough in his U.S. patent (U.S. Patent 127,568) in 1872. "I, Robert Chesebrough, have invented a new and useful product from petroleum which I have named Vaseline..."
The name "vaseline" is said by the manufacturer to be derived from German Wasser "water" + Greek έλαιον (elaion) "oil".Vaseline was made by the Chesebrough Manufacturing Company until the company was purchased by Unilever in 1987. Uses
While Vaseline can be used as a lubricant, it can also be used as a moisture insulator for local skin conditions characterized by tissue dehydration.