Adjuvant
From Wikipedia, the free encyclopedia
In medicine, adjuvants are agents which modify the effect of other agents while having few if any direct effects when given by themselves. In this sense, they are very roughly analogous with chemical catalysts.
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[edit] Pharmacology
In pharmacology, adjuvants are drugs that have few or no pharmacological effects by themselves, but may increase the efficacy or potency of other drugs when given at the same time.
For instance, caffeine has minimal analgesic effect on its own, but may have an adjuvant effect when given with paracetamol [citation needed].
[edit] Immunology
Similarly, in immunology an adjuvant is an agent which, while not having any specific antigenic effect in itself, may stimulate the immune system, increasing the response to a vaccine. Aluminum salts are used in some human vaccines , although a recent study [2] revealed aluminum adjuvants can cause neuron death. The compound QS21 is under investigation as a possible immunological adjuvant as is Novartis's (formley Chiron) MF59 . Another market-approved adjuvant and carrier system are virosomes. During the last two decades a variety of technologies have been investigated to improve the widely used, but unfavorable adjuvants based on aluminum salts. These salts develop their effect by inducing a local inflammation, which is also the basis for the extended side-effect pattern of this adjuvant. By contrast, the adjuvant capabilities of virosomes are independent of any inflammatory reaction. Virosomes contain influenza virus-derived membrane-bound hemagglutinin and neuraminidase, which amplify fusogenic activity and therefore facilitates the uptake into antigen presenting cells (APC) and induce a natural antigen-processing pathway. The delivery of the antigen by virosomes to the immune system in an almost natural way may be a main reason why virosome-based vaccines stand out due to their excellent safety profile.
[edit] Oncology
The terms adjuvant and neoadjuvant have special meanings in oncology. Adjuvant therapy refers to additional treatment, usually given after surgery where all detectable disease has been removed, but where there remains a statistical risk of relapse due to occult disease. If known disease is left behind following surgery, then further treatment is not technically "adjuvant".
For example, radiotherapy or chemotherapy are commonly given as adjuvant treatments after surgery for a breast cancer. Oncologists use statistical evidence to assess the risk of disease relapse before deciding on the specific adjuvant therapy. The aim of adjuvant treatment is to improve disease-specific and overall survival. Because the treatment is essentially for a risk, rather than for provable disease, it is accepted that a proportion of patients who receive adjuvant therapy will already have been cured by their primary surgery.
Adjuvant chemotherapy and radiotherapy are often given following surgery for many types of cancer, including colon cancer, lung cancer, pancreatic cancer, breast cancer, prostate cancer, and some gynaecological cancers.
Neoadjuvant therapy, in contrast to adjuvant therapy, is given before the main treatment. For example, chemotherapy that is given before removal of a breast is considered neoadjuvant chemotherapy.
Finally concomitant chemotherapy refers to administering medical treatments at the same time as other therapies, such as radiation.
[edit] Other uses
The term adjuvant was also adopted by visionary thinker Buckminster Fuller to describe Kiyoshi Kuromiya, who served as a writing partner for several books, including Critical Path, and the posthumously published Cosmography. Fuller chose that word very deliberately to describe the unique role that Kiyoshi had played in his last publications which he wished to acknowledge was a very active one. Fuller's usage comes from the dictionary's definition as "serving to aid or contribute; one that helps or facilitates."
[edit] References
- ↑ "Aluminum salts in vaccines--US perspective" by N. W. Baylor, W. Egan and P. Richman (2002) Vaccine Volume 20 Suppl 3, pages S18-23. Entrez PubMed 12184360
- ↑ "Prototype Alzheimer's disease epitope vaccine induced strong Th2-type anti-Abeta antibody response with Alum to Quil A adjuvant switch" by A. Ghochikyan, M. Mkrtichyan, I. Petrushina, N. Movsesyan, A. Karapetyan, D. H. Cribbs and M. G. Agadjanyan (2005) Vaccine online December 5, 2005 ahead of print publication. Entrez PubMed 16368167
- ↑ NIH "Chiron Corporation will produce the H9N2 vaccine at its manufacturing facility in Siena, Italy. The company will prepare different dosages of the vaccine, which is based on an inactivated strain of the H9N2 virus developed by the Centers for Disease Control and Prevention. Some dosages will contain Chiron’s MF59 adjuvant—a substance designed to boost the vaccine’s protective effect."
[edit] See also
[edit] External links
- Straight.com - 'Vaccines show sinister side', Pieta Woolley (March 23, 2006)
- WashingtonPost.com - 'Researchers Race to Boost Supply of Bird Flu Vaccine: Additives Studied as Way to Help Fight Potential Pandemic', David Brown, Washington Post (February 12, 2006)de:Adjuvans (Pharmakologie)
