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001-es BibID:	BIBFORM028691
Első szerző:	Szondy Zsuzsanna (molekuláris sejtbiológus, biokémikus)
Cím:	The effect of time of addition of glutamine or nucleosides on proliferation of rat cervical lymph-node T-lymphocytes after stimulation by concanavalin A / Zsuzsa Szondy, Eric A. Newsholme
Dátum:	1991
ISSN:	0264-6021
Megjegyzések:	Addition of concanavalin A to T-cell lymphocytes from rat cervical lymph nodes increases the activity of glutaminase within 1 h and those of carbamoyl-phosphate synthase II and aspartate transcarbamoylase within 3 h. There was a similar time course for the effects of concanavalin A on rates of glutamine utilization, which was increased within 1 h, and on pyrimidine nucleotide synthesis, which was increased by 40% at 2 h and by 100% at 3 h. 2. A delay in the addition of glutamine to the culture medium after addition of concanavalin A caused a decrease in [3H]thymidine incorporation only after 4-6 h. In the absence of glutamine, delay in addition of guanosine or inosine caused a decrease in [3H]thymidine incorporation only after 6-8 h after the addition of concanavalin A. 3. In contrast, a delay in addition of adenosine or uridine to the culture medium had an immediate effect (i.e. within 2 h) on the rate of incorporation of [3H]thymidine. It is suggested that adenosine and uridine have specific effects on proliferation via specific receptors for these nucleosides in the membrane.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban külföldön készült közlemény
Megjelenés:	The Biochemical Journal. - 278 : 2 (1991), p. 471-474. -
További szerzők:	Newsholme, Eric A.
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM028690
Első szerző:	Szondy Zsuzsanna (molekuláris sejtbiológus, biokémikus)
Cím:	The effect of various concentrations of nucleobases, nucleosides or glutamine on the incorporation of [3H]thymidine into DNA in rat mesenteric-lymph-node lymphocytes stimulated by phytohaemagglutinin / Zsuzsa Szondy, Eric A. Newsholme
Dátum:	1990
ISSN:	0264-6021
Megjegyzések:	The rate of [3H]thymidine incorporation into DNA was measured in phytohaemagglutinin-stimulated lymph-node lymphocytes of the rat. 2. Addition of nucleobases or nucleosides to culture medium that already contained 0.2 mM-glutamine had a small stimulatory effect on incorporation. At lower concentrations of glutamine, adenosine (even at 1 microM) caused a marked increase in the rate of incorporation. 3. In the absence of added glutamine, addition of nucleosides or nucleobases markedly increased the rate of incorporation: nucleosides were more effective than nucleobases; and the rate of proliferation in the presence of 10 microM-adenosine plus 10 microM-uridine was similar to that in the presence of optimal concentrations of glutamine. 4. The rate of incorporation was dramatically decreased by an inhibitor of the pathway of pyrimidine nucleotide synthesis de novo. Addition of the pyrimidine nucleosides completely overcame the inhibition; addition of the pyrimidine nucleobases was much less effective. 5. These results indicate that, for proliferation of lymphocytes, glutamine is not essential and can be partially or totally replaced by nucleosides and, to some extent, by nucleobases.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban külföldön készült közlemény
Megjelenés:	The Biochemical Journal. - 270 : 2 (1990), p. 437-440. -
További szerzők:	Newsholme, Eric A.
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM028689
Első szerző:	Szondy Zsuzsanna (molekuláris sejtbiológus, biokémikus)
Cím:	The rate of the AMP/adenosine substrate cycle in concanavalin- A-stimulated rat lymphocytes / Zsuzsa Szondy, Eric A. Newsholme
Dátum:	1989
ISSN:	0264-6021
Megjegyzések:	The effect of adenosine on the metabolism of prelabelled adenine nucleotides was investigated in concanavalin-A-stimulated rat lymphocytes. Adenosine in the presence of the adenosine deaminase inhibitor, deoxycoformycin, caused a 2-fold increase in the ATP concentration. This effect was, in part, countereacted by an increased rate of adenine nucleotide catabolism, which could be explained by a stimulation of AMP deaminase (EC 3.5.4.6). At the same time a continuous rate of labelled adenosine production was found, which was not affected by the increased ATP concentration and which could only be detected by the trapping effect of a high concentration of added unlabelled adenosine. It is concluded that the rate of the substrate cycle between AMP and adenosine is low (1.9 +/- 0.2 nmol/h per 10(7) cells) in comparison to the rate of AMP deamination.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban külföldön készült közlemény
Megjelenés:	The Biochemical Journal. - 261 : 3 (1989), p. 739-742. -
További szerzők:	Newsholme, Eric A.
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM028688
Első szerző:	Szondy Zsuzsanna (molekuláris sejtbiológus, biokémikus)
Cím:	The effect of glutamine concentration on the activity of carbamoyl-phosphate synthase II and on the incorporation of [3H]thymidine into DNA in rat mesenteric lymphocytes stimulated by phytohaemagglutinin / Zsuzsa Szondy, Eric A. Newsholme
Dátum:	1989
Megjegyzések:	The maximum catalytic activities of carbamoyl-phosphate synthase II, a limiting enzyme for pyrimidine nucleotide synthesis, are very much less than those of glutaminase, a limiting enzyme for glutamine utilization, in lymphocytes and macrophages; and the flux through the pathway for pyrimidine formation de novo is only about 0.4% of the rate of glutamine utilization by lymphocytes. The Km of synthase II for glutamine is about 16 microM and the concentration of glutamine necessary to stimulate lymphocyte proliferation half-maximally is about 21 microM. This agreement suggests that the importance of glutamine for these cells is provision of nitrogen for biosynthesis of pyrimidine nucleotides (and probably purine nucleotides). However, the glutamine concentration necessary for half-maximal stimulation of glutamine utilization (glutaminolysis) by the lymphocytes is 2.5 mM. The fact that the rate of glutamine utilization by lymphocytes is markedly in excess of the rate of the pathway for pyrimidine nucleotide synthesis de novo and that the Km and 'half-maximal concentration' values are so different, suggests that the glutaminolytic pathway is independent of the use of glutamine nitrogen for pyrimidine synthesis.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban külföldön készült közlemény
Megjelenés:	The Biochemical Journal.. - 261 : 3 (1989), p. 979-983. -
További szerzők:	Newsholme, Eric A.
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat
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