The present invention includes peptide compositions for improving cellular communication mechanisms, repairing metabolic errors, and for treatment of AD, dementia and other neurological conditions. The proline rich peptide complexes (PRPC) of the present invention are isolated from colostrinin and can be added in nutritional and other food supplements. Additionally, the present invention describes novel communication system governing circa two hundreds of different types of cells in each mammal that modulates the activities of the organism through the biological computer present in every living cell. Different type of cells can communicate with other through biological computer connected with five different communication networks. In addition to the biological computer controls cell metabolism and function assigned to a given type of cell. Such system permits smooth cooperation between 10.sup.17 cells forming the body. Within a communication system each network utilizes different types of signals, with about 69 different signals operating within each network. These numbers permit the formation of a circa of 10.sup.99 combinations approaching the infinity and utilizing different types of signals. Practically each cell biological computer can recognize signals delivered by every one in the network.