SUBSTRATE REGULATION BY SKELETAL MUSCLE AFTER HINDLIMB SUSPENSION

后肢悬吊后骨骼肌对基质的调节

• 批准号: 6205900
• 负责人: LOREN A BERTOCCI
• 金额: $ 0.7万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-08-15 至 2000-08-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6205900
• 关键词: Mammalia; biomedical resource; infant mortality; low birth weight infant human; minerals; nuclear magnetic resonance spectroscopy; technology /technique

31P MRS has been used to non-invasively assess the effects of MgSO4 compared to Na2SO4 infusions on brain phosphorylated compounds and intracellular pH (pHi) before, during and after hypoxia-ischemia. Swine were infused with either MgSO4 or equivalent volumes of Na2SO4 and each group underwent hypoxia-ischemia. Evaluation of systemic physiologic variables indicated that the groups were well matched. 31P MRS provides the ability to determine intracellular ionized Mg concentration [Mg]i non-invasively by quantitating the Mg-dependent changes in the frequency of the 31P MR signal from the phosphorus atoms of NTP. Calculated [Mg]i was similar between groups at control and significantly increased relative to control in both groups during hypoxia-ischemia. However, there were group differences with higher values of [Mg]i during hypoxia-ischemia in the MgSO4 infused compared to the Na2SO4 infused animals. Following hypoxia-ischemia there was a longer time for [Mg]i to return to baseline values in MgSO4 compared to Na2SO4 infused mini-swine. There are three potential reasons for the group differences in [Mg]i. First, the greater intracellular acidosis during and following hypoxia-ischemia in MgSO4 compared to Na2SO4 animals could reduce binding of Mg to cellular proteins and result in an elevated ionized fraction. Second, hydrolysis of NTP during brain energy failure from hypoxia-ischemia would be expected to free Mg normally complexed to NTP. This could contribute to the greater increase in [Mg]i of MgSO4 animals since this group experienced a greater reduction in NTP compared to Na2SO4 infused animals. Finally, it could be speculated that there is movement of Mg from the extracellular to the intracellular compartment. Although alterations in [Mg]i remain incompletely understood, the observed changes indicate that Mg may be influencing important variables not only externally at the cell surface via changes in extracellular fluid [Mg], but also within the cell itself. (Service 11) REPORT PERIOD: (09/01/97-08/31/98)

31P MRS已被用于非侵入性评估的影响， MgSO4与Na2SO4输注对脑磷酸化化合物的影响比较 和细胞内pH（pHi）。 猪被注入MgSO4或等体积的Na2SO4 各组均行缺氧缺血处理。 评价全身 生理变量表明各组匹配良好。 31P MRS提供了测定细胞内离子化Mg的能力 浓度[Mg]i非侵入性地通过定量Mg依赖性 来自磷的31P MR信号频率的变化 NTP的原子 对照组间计算的[Mg]i相似 并且在两组中相对于对照组显著增加， 缺氧缺血 然而，有组间差异， MgSO4输注时缺氧缺血期间[Mg]i值比较 注射Na2SO4的动物。 缺氧缺血后， MgSO4中[Mg]i恢复至基线值的时间较长， 注射Na2SO4的小型猪 有三个潜在的原因 [Mg]i的组间差异。 首先，更大的细胞内 在MgSO4中缺氧缺血期间和之后的酸中毒与 Na2SO4动物可减少Mg与细胞蛋白的结合， 导致电离分数升高。 第二，NTP的水解 在缺氧缺血引起的脑能量衰竭期间， 游离Mg通常与NTP络合。 这可能有助于 自该组以来，MgSO 4动物的[Mg]i增加幅度更大 与Na2SO4输注相比，NTP降低幅度更大 动物 最后，可以推测， 从细胞外区室到细胞内区室。 虽然 [Mg]i的变化仍然不完全理解，观察到的 变化表明，镁可能会影响重要的变量， 仅在细胞表面通过细胞外液的变化 [Mg]，但也在细胞内。 （服务11）报告期： (09（1997年1月至1998年8月31日）