Product Development and Drug Testing. To predict toxicity, corrosivity, and other safety variables as well as the effectiveness of new products, traditional testing of chemicals, consumer products, medical devices, and new drugs has involved the use of animals.r. Gerhard Zbinden, one of the world's leading toxicologists, once described a standard in vivo test as little more than âa ritual mass execution of animals.â The testing of just one substance alone, be it a potential drug or toxic chemical, can involve using up to 800 animals and cost over $6 million. [1].
Paleness should be distinguished from other causes of prominent white skin 1  : Fair skin is genetically determined skin hue with low concentration of skin pigment (melanin) in the skin.
Down syndrome results when abnormal cell division involving chromosome 21 occurs. These cell division abnormalities result in extra genetic material from chromosome 21, which is responsible for the characteristic features and developmental problems of Down syndrome. Any one of three genetic variations can cause Down syndrome: 1  Trisomy 21. 2  About 95 percent of the time, Down syndrome is caused by trisomy 21 â the child has three copies of chromosome 21 (instead of the usual two copies) in all cells.