Arginine deprivation, growth inhibition and tumour cell death: 2. Enzymatic degradation of arginine in normal and malignant cell cultures

Arginase added to culture medium reduced arginine to negligible levels within approximately 6 h, and enzyme activity persisted relatively undiminished for at least 3 days. Human and bovine arginase proved equally effective. The response of normal cells was to enter G1 (G0) arrest, from which most of the cells could be recovered weeks later. In contrast, malignant cell lines treated with unpegylated or pegylated enzyme resulted in cell death on a massive scale within 3 - 5 days, with a very low to negligible percentage of cells (8 days. Arginine decarboxylase caused malignant cell arrest at the same units per millilitre as arginase. Its breakdown product, agmatine, was relatively nontoxic in the presence of arginine, but exacerbated cell death above millimolar concentration in its absence. Although ornithine failed to rescue cells from deprivation, citrulline recovered cells in all cases, although less well in fast-growing tumour cell populations, whereas readdition of arginine failed to work unless a complete medium change was given (because of the persistence of the enzymes in the medium catabolising its destruction). The advantages and disadvantages of these two arginine-catabolising enzymes are discussed, and compared with arginine deiminase

От концепции ноосферы к концепции нооэтики

However, the idea of a “noosphere” of Teilhard de Chardin is perceived by some today, it was a concept that did not gain ground, although it had its eminent champions such as Huxley, Lerua and Vernadsky. The notion of de Chardin was too ephemeral a concept to take on board, especially with its spiritual basis that did not fit with scientific thinking. This underlying idea, however, did help us nevertheless to focus on a newly emerging era in evolution, one that would change the direction in which “natural” forces might have led us. It has become increasingly obvious that this new direction could be largely under human control and this could impact many different ways on the future of planet Earth (and probably beyond). As a wake-up call, the noosphere was therefore important in one respect, which emphasised the fact that man must set about regulating the “knowledge-sphere” and taking greater responsibility for his action in the evolutionary process, i.e. in the behaviour through which he applies this knowledge. Little seems to have been done constructively about this matter, but the knowledge-sphere is now with us in the guise of the internet and other media systems that could never have been perceived by the 20th advocates of the noosphere concept. Evolutionary development has to be considered in much greater depth because it is hereafter going to be central to any debate about the future. It follows that the problems of what constitutes useful knowledge and how to control of its application have become increasingly urgent, otherwise possible scenarios would include some that would definitely be detrimental to future existence of mankind, as was faced when atomic warfare was first let loose. The wake-up call today should not be through such drastic measures. The general public is greatly in need of education about the issues facing mankind and the planet. Concerted action on a global scale is needed to put in place constructive approaches, bottomup and top-down, that might help human society, the biosphere, and our planet (and things beyond) to face the future with confidence and understanding. It is hoped that what is presented here goes some way to opening up a fuller debate of an underlying deficiency in the present state relating to our control of human knowledge and where it might take us, rather than proferring solution to the problems.В статье изложен анализ формирования нооэтики как современной стадии развития биоэтики. Философской и мировоззренческой основой нооэтики признается современная этическая оценка последствий трансформации биосферы в ноосферу в результате жизнедеятельности человека. Представлены исторические предпосылки формирования концепции ноосферы и нооэтики в рамках эволюционной теории ряда исследователей -предшественников. Значимость концепции нооэтики определяется анализом успехов и неудач в работе по защите окружающей среды, а также созданием этической платформы менеджмента в сфере биобезопасности ноосферы. Концепции ноосферы и нооэтики рассматриваются как составляющие вектора развития цивилизации XXI ст. и современного мировоззрения