2,346 research outputs found
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
ΠΡ ΠΊΠΎΠ½ΡΠ΅ΠΏΡΠΈΠΈ Π½ΠΎΠΎΡΡΠ΅ΡΡ ΠΊ ΠΊΠΎΠ½ΡΠ΅ΠΏΡΠΈΠΈ Π½ΠΎΠΎΡΡΠΈΠΊΠΈ
However, the idea of a βnoosphereβ 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 βnaturalβ 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 βknowledge-sphereβ 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.Π ΡΡΠ°ΡΡΠ΅ ΠΈΠ·Π»ΠΎΠΆΠ΅Π½ Π°Π½Π°Π»ΠΈΠ· ΡΠΎΡΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΡ Π½ΠΎΠΎΡΡΠΈΠΊΠΈ ΠΊΠ°ΠΊ ΡΠΎΠ²ΡΠ΅ΠΌΠ΅Π½Π½ΠΎΠΉ ΡΡΠ°Π΄ΠΈΠΈ ΡΠ°Π·Π²ΠΈΡΠΈΡ Π±ΠΈΠΎΡΡΠΈΠΊΠΈ. Π€ΠΈΠ»ΠΎΡΠΎΡΡΠΊΠΎΠΉ ΠΈ ΠΌΠΈΡΠΎΠ²ΠΎΠ·Π·ΡΠ΅Π½ΡΠ΅ΡΠΊΠΎΠΉ ΠΎΡΠ½ΠΎΠ²ΠΎΠΉ Π½ΠΎΠΎΡΡΠΈΠΊΠΈ ΠΏΡΠΈΠ·Π½Π°Π΅ΡΡΡ ΡΠΎΠ²ΡΠ΅ΠΌΠ΅Π½Π½Π°Ρ ΡΡΠΈΡΠ΅ΡΠΊΠ°Ρ ΠΎΡΠ΅Π½ΠΊΠ° ΠΏΠΎΡΠ»Π΅Π΄ΡΡΠ²ΠΈΠΉ ΡΡΠ°Π½ΡΡΠΎΡΠΌΠ°ΡΠΈΠΈ Π±ΠΈΠΎΡΡΠ΅ΡΡ Π² Π½ΠΎΠΎΡΡΠ΅ΡΡ Π² ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΠ΅ ΠΆΠΈΠ·Π½Π΅Π΄Π΅ΡΡΠ΅Π»ΡΠ½ΠΎΡΡΠΈ ΡΠ΅Π»ΠΎΠ²Π΅ΠΊΠ°. ΠΡΠ΅Π΄ΡΡΠ°Π²Π»Π΅Π½Ρ ΠΈΡΡΠΎΡΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΠΏΡΠ΅Π΄ΠΏΠΎΡΡΠ»ΠΊΠΈ ΡΠΎΡΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΠΊΠΎΠ½ΡΠ΅ΠΏΡΠΈΠΈ Π½ΠΎΠΎΡΡΠ΅ΡΡ ΠΈ Π½ΠΎΠΎΡΡΠΈΠΊΠΈ Π² ΡΠ°ΠΌΠΊΠ°Ρ
ΡΠ²ΠΎΠ»ΡΡΠΈΠΎΠ½Π½ΠΎΠΉ ΡΠ΅ΠΎΡΠΈΠΈ ΡΡΠ΄Π° ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°ΡΠ΅Π»Π΅ΠΉ -ΠΏΡΠ΅Π΄ΡΠ΅ΡΡΠ²Π΅Π½Π½ΠΈΠΊΠΎΠ². ΠΠ½Π°ΡΠΈΠΌΠΎΡΡΡ ΠΊΠΎΠ½ΡΠ΅ΠΏΡΠΈΠΈ Π½ΠΎΠΎΡΡΠΈΠΊΠΈ ΠΎΠΏΡΠ΅Π΄Π΅Π»ΡΠ΅ΡΡΡ Π°Π½Π°Π»ΠΈΠ·ΠΎΠΌ ΡΡΠΏΠ΅Ρ
ΠΎΠ² ΠΈ Π½Π΅ΡΠ΄Π°Ρ Π² ΡΠ°Π±ΠΎΡΠ΅ ΠΏΠΎ Π·Π°ΡΠΈΡΠ΅ ΠΎΠΊΡΡΠΆΠ°ΡΡΠ΅ΠΉ ΡΡΠ΅Π΄Ρ, Π° ΡΠ°ΠΊΠΆΠ΅ ΡΠΎΠ·Π΄Π°Π½ΠΈΠ΅ΠΌ ΡΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΏΠ»Π°ΡΡΠΎΡΠΌΡ ΠΌΠ΅Π½Π΅Π΄ΠΆΠΌΠ΅Π½ΡΠ° Π² ΡΡΠ΅ΡΠ΅ Π±ΠΈΠΎΠ±Π΅Π·ΠΎΠΏΠ°ΡΠ½ΠΎΡΡΠΈ Π½ΠΎΠΎΡΡΠ΅ΡΡ. ΠΠΎΠ½ΡΠ΅ΠΏΡΠΈΠΈ Π½ΠΎΠΎΡΡΠ΅ΡΡ ΠΈ Π½ΠΎΠΎΡΡΠΈΠΊΠΈ ΡΠ°ΡΡΠΌΠ°ΡΡΠΈΠ²Π°ΡΡΡΡ ΠΊΠ°ΠΊ ΡΠΎΡΡΠ°Π²Π»ΡΡΡΠΈΠ΅ Π²Π΅ΠΊΡΠΎΡΠ° ΡΠ°Π·Π²ΠΈΡΠΈΡ ΡΠΈΠ²ΠΈΠ»ΠΈΠ·Π°ΡΠΈΠΈ XXI ΡΡ. ΠΈ ΡΠΎΠ²ΡΠ΅ΠΌΠ΅Π½Π½ΠΎΠ³ΠΎ ΠΌΠΈΡΠΎΠ²ΠΎΠ·Π·ΡΠ΅Π½ΠΈΡ
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