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排序方式: 共有174条查询结果,搜索用时 265 毫秒
81.
Marcin R Tatara Witold Krupski Maria Szpetnar Andrzej D?browski Pawe? Bury Anna Szabelska Anna Charuta Anna Boguszewska-Czubara Ryszard Maciejewski Grzegorz Wallner 《Experimental biology and medicine (Maywood, N.J.)》2015,240(12):1557-1563
The aim of the study was to determine one-year effects of total gastrectomy on plasma silicon and free amino acid concentrations in patients and evaluate changes of volumetric bone mineral density (vBMD) in lumbar spine. Eight patients were enrolled to the control (CTR) group. Six patients subjected to total gastrectomy (GX group) were included to the experimental group. vBMD in trabecular and cortical bone was measured in lumbar vertebrae at baseline (before surgery) and one year later using quantitative computed tomography. Plasma concentrations of silicon and free amino acids were determined at baseline and one year later using photometric method and ion-exchange chromatography. Body weights within CTR and GX groups were not different after one-year follow-up when compared to the baseline values (P > 0.05). An average annual decrease of vBMD in the trabecular bone in the gastrectomized patients reached 15.0% in lumbar spine and was significantly different in comparison to the percentage changes observed in CTR group (P = 0.02). One-year percentage change of vBMD in the cortical bone in L1 and L2 has shown significantly decreased values by 10.5 and 9.1% in the GX group when compared to the percentage change observed in the controls (P < 0.05). Plasma concentration of adipic acid was significantly higher by 101.6% one year after total gastrectomy procedure in the patients when compared to the baseline value (P = 0.01). Plasma concentration of silicon was significantly lowered by 26.7% one year after the total gastrectomy when compared to the baseline value (P = 0.009). Total gastrectomy in patients has induced severe osteoporotic changes in lumbar spine within one-year period. The observed osteoporotic changes were associated with decreased plasma concentration of silicon indicating importance of exocrine and endocrine functions of stomach for silicon homeostasis maintenance. Gastrectomy-induced bone loss was not related to decreased amino acid concentration in plasma obtained from overnight fasted patients. 相似文献
82.
Mikael K. Schnizler Roman Bogdan Nicolas R. Bury Wolfgang Clauss 《生物化学与生物物理学报:生物膜》2007,1768(2):317-323
Waterborne free silver can cause osmo- and ionoregulatory disturbances in freshwater organisms. The effects of a short-term exposure to extracellular Ag+ ions on membrane currents were investigated in voltage-clamped defolliculated Xenopus oocytes. At a holding potential of − 60 mV, ionic silver (1 μM Ag+) increased inward currents (=IAg) from − 8 ± 2 nA to − 665 ± 41 nA (n = 74; N = 27). IAg activated within 2 min of silver exposure and then rose impetuously. This current was largely reversible by washout and repeatable. IAg reversed around − 30 mV and rectified slightly at more positive potentials. Na+-free bath conditions reduced the silver-induced current to a smaller but sustained current. The response to silver was abolished by the Cl− channel blockers DIDS and SITS, whereas niflumic acid strongly potentiated IAg. Intraoocyte injection of AgNO3 to about 1 mM [Ag]i strongly potentiated IAg. Extracellular application of either dithiothreitol (DTT), a compound known to reduce disulfide bridges, or l-cysteine abolished Ag+-activated increase of membrane current. In contrast, n-ethylmaleimide (NEM) which oxidizes SH-groups potentiated IAg. Hypoosmotic bath solution significantly increased IAg whereas hyperosmolar conditions attenuated IAg. The activation of IAg was largely preserved after chelation of cytosolic Ca2+ ions with BAPTA/AM. Taken together, these data suggest that Xenopus oocytes are sensitive to short-term exposure to waterborne Ag+ ions and that the elicited membrane currents result from extra- and intracellular action of Ag+ ions on peptide moieties at the oocyte membrane but may also affect conductances after internalization. 相似文献
83.
Schnizler MK Bogdan R Bennert A Bury NR Fronius M Clauss W 《Biochimica et biophysica acta》2007,1768(2):317-323
Waterborne free silver can cause osmo- and ionoregulatory disturbances in freshwater organisms. The effects of a short-term exposure to extracellular Ag+ ions on membrane currents were investigated in voltage-clamped defolliculated Xenopus oocytes. At a holding potential of -60 mV, ionic silver (1 microM Ag+) increased inward currents (=I(Ag)) from -8+/-2 nA to -665+/-41 nA (n=74; N=27). I(Ag) activated within 2 min of silver exposure and then rose impetuously. This current was largely reversible by washout and repeatable. I(Ag) reversed around -30 mV and rectified slightly at more positive potentials. Na+-free bath conditions reduced the silver-induced current to a smaller but sustained current. The response to silver was abolished by the Cl- channel blockers DIDS and SITS, whereas niflumic acid strongly potentiated I(Ag). Intraoocyte injection of AgNO3 to about 1 mM [Ag]i strongly potentiated I(Ag). Extracellular application of either dithiothreitol (DTT), a compound known to reduce disulfide bridges, or L-cysteine abolished Ag+-activated increase of membrane current. In contrast, n-ethylmaleimide (NEM) which oxidizes SH-groups potentiated I(Ag). Hypoosmotic bath solution significantly increased I(Ag) whereas hyperosmolar conditions attenuated I(Ag). The activation of I(Ag) was largely preserved after chelation of cytosolic Ca2+ ions with BAPTA/AM. Taken together, these data suggest that Xenopus oocytes are sensitive to short-term exposure to waterborne Ag+ ions and that the elicited membrane currents result from extra- and intracellular action of Ag+ ions on peptide moieties at the oocyte membrane but may also affect conductances after internalization. 相似文献
84.
Katarzyna Wegrzyn Elzbieta Zabrocka Katarzyna Bury Bartlomiej Tomiczek Milosz Wieczor Jacek Czub Urszula Uciechowska María Moreno-del
Alamo Urszula Walkow Igor Grochowina Rafal Dutkiewicz Janusz M Bujnicki Rafael Giraldo Igor Konieczny 《Nucleic acids research》2021,49(6):3394
An essential feature of replication initiation proteins is their ability to bind to DNA. In this work, we describe a new domain that contributes to a replication initiator sequence-specific interaction with DNA. Applying biochemical assays and structure prediction methods coupled with DNA–protein crosslinking, mass spectrometry, and construction and analysis of mutant proteins, we identified that the replication initiator of the broad host range plasmid RK2, in addition to two winged helix domains, contains a third DNA-binding domain. The phylogenetic analysis revealed that the composition of this unique domain is typical within the described TrfA-like protein family. Both in vitro and in vivo experiments involving the constructed TrfA mutant proteins showed that the newly identified domain is essential for the formation of the protein complex with DNA, contributes to the avidity for interaction with DNA, and the replication activity of the initiator. The analysis of mutant proteins, each containing a single substitution, showed that each of the three domains composing TrfA is essential for the formation of the protein complex with DNA. Furthermore, the new domain, along with the winged helix domains, contributes to the sequence specificity of replication initiator interaction within the plasmid replication origin. 相似文献
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86.
Judson S. Bury 《BMJ (Clinical research ed.)》1909,2(2545):1025-1026
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