We investigate the properties of 3He, 4He, 6He, 7Li and 16O nuclei in nuclear matter of finite temperature and density. A Dyson expansion of the many-body Green function leads to few-body equations that are solved using the ntegro-Differential Equation Approach (IDEA) and the Antisymmetrized Molecular Dynamics (AMD) methods. The use of the latter method allows us to trace the individual movement of the wave packet for each nucleon and the formation and disintegration of quasi-nuclei in a changing thermodynamical nuclear matter environment.