Tuesday, February 26, 2013
Booster shots may be needed at later dates to ensure that active immunity is still effective. Vaccines are available against many formerly dangerous diseases including polio, measles an d diphtheria. Immunization programmes for children have virtually eliminated most common childhood diseases, and confer immunity into adult life. But vaccination is advisable for travelers to countries where they may contract potentially fatal diseases not previously encountered. Sometimes antibodies themselves from external sources are injected into the body to provide protection without stimulating the immune system. This is called artificial passive immunity and is useful in providing instant protection where a disease might kill the person before their active immune system has time to come into operation. Examples include gamma globulin, given against hepatitis A infection; anti toxin to treat tetanus; and anti rabies injections.
Wednesday, February 20, 2013
Other sliming diets put the body in a defensive stance. Because its calorie intake has been severely reduced the body reduces its metabolic rate to conserve its fat energy reserves and actually burns lean muscle tissues in order to provide energy. When the diet stops the body diverts as much spare food energy as possible to build up its fat reserves in case another calorie famine happens and in consequence the diet regains lost weight and ends with more fat than before