Growth factors and growth control

Cell proliferation in normal and malignant transformed cells: thermodynamic model of signal transduction

We present a new thermodynamic model for the mechanism of activation and regulation of cell proliferation in the G1 stage. In this model, the interactions between growth factors and transmembrane proteins play a crucial role in cell growth control for a normal tissue-culture system. We calculate a phase diagram of normal and malignant transformed states of a cell signal transduction system. We propose thermodynamic reasons why cancer cells can continually grow without activation by the growth factors.

Growth factors: regulation of normal and neoplastic growth

This paper presents an overview of current trends in growth factor research. The first part of the review considers the current classification of growth factors and their receptors. A model of cell proliferation regulation by growth factors is then presented. The final section reviews the latest concepts of the involvement of growth factors in the development of neoplasia.

Growth retardation in senescent arterial smooth muscle cells and its reversal following brain stimulation: implications for atherogenesis

Advancing age and psychosocial stress are each associated with a rising incidence of atherosclerosis. In this investigation we attempted to answer the question of whether they are independent of each other or not. Since a key feature of atherosclerosis is the proliferation of arterial smooth muscle cells (ASMC), we transplanted aortic tissue from aged rats, half of which had received hypothalamic stimulation, as a model for stress, to growth supporting medium, immediately after stimulation and observed their growth behavior for a period of 4 months. Similar observations were carried out on young animals for comparison. Although there was little difference in outgrowth frequency of explants from young animals between stimulated and non-stimulated subjects, in the case of the older rats, explants from animals which were not stimulated were considerably retarded in their growth, whereas those from subjects which had received HS, grew as well as those of the younger ones. These results show that HS can reverse the growth decline in aortic tissues explanted from senescent rats. They also suggest that age per se is not atherogenic in terms of proliferative behavior of ASMC, whereas when interacted with a stressful condition, this may be the case. Since in the elderly there is a decreased tolerance to stress, the 'atherogenic' effects of age in these individuals may be mediated through the stress response.