Introduction. A broken arm or wrist is usually caused by a fall onto an outstretched arm. It typically takes about six to eight weeks to heal in adults, and less time in children. Doctors refer to all breaks or cracks in bones as fractures.Go to your nearest accident and emergency (A&E) department if you think you or your child has broken a bone.t typically takes about six to eight weeks to heal in adults, and less time in children. Doctors refer to all breaks or cracks in bones as fractures. Go to your nearest accident and emergency (A&E) department if you think you or your child has broken a bone.
In contrast, the overwhelming majority of antigens for T cells are proteins, and these must be fragmented and recognized in association with MHC products expressed on the surface of nucleated cells, not in soluble form.
CD4+ cells recognize antigen presented in the context of class II major histocompatibility complex (MHC), while CD8+ cells recognize antigen presented in the context of class I MHC. CD4+ T helper subsets include T helper type 1 (Th1), T helper type 2 (Th2), and T helper type 17 (Th17) cells (figure 1 and table 1) [1]. There is evidence that each of these subsets is involved in the defense against a certain subset of micro-organisms.