Practice Essentials. The term âpernicious anemiaâ is an anachronismâit dates from the era when treatment had not yet been discovered, and the disease was fatalâbut it remains in use for megaloblastic anemia resulting from vitamin B12 deficiency due to lack of intrinsic factor (IF).
The definition of a fan is  a person who is very enthusiastic about someone or something, or a device that moves and cools the air. An example of a fan is a person who only wears gold and red in support of the San Francisco 49ers. An example of a fan is an electrical device with moving blades that cools air.
One that supports, protects, or champions someone or something, such as an institution, event, or cause; a sponsor or benefactor: a patron of the arts. 2. A customer, especially a regular customer. 3. (also pÃ¤-trÅnâ²) The owner or manager of an establishment, especially a restaurant or an inn of France or Spain.