Antigenic variation is employed by a number of different protozoan parasites. Trypanosoma brucei (the model for study of protozoan antigenic variation) and Plasmodium falciparum are some of the most well studied examples of protozoan parasites that exhibit antigenic variation.ntigenic variation is the expression of various alternative forms of antigen on the cell surface. Whereas phase variation is the phenotypic switch that is usually reversible and is referred to as an ON-OFF switch.
NO: Amitriptyline is a tricyclic antidepressant for depression and some forms of anxiety, sometimes used for chronic pain or migraine. Xanax is a triazolobenzodiazepine or a benzodiazepine with an extra triazole ring structure. It is quite addicting and has a short half-life.
Amitriptyline belongs to a group of drugs called tricyclic antidepressants. Although theyâre still used to treat anxiety and depression, theyâre also now widely used at lower doses to help block the chronic (long-term) pain of some rheumatic conditions.he main aim of lower-dose amitriptyline is to relieve pain, relax muscles and improve sleep, but it may also help reduce any anxiety or depression resulting from the pain.