Gagnon Roy E, Gagnon Faith A, Macnab Andrew J, LeBlanc Jacques G
Department of Pediatrics, Children's & Women's Health Centre, University of British Columbia, Vancouver, Canada.
Metab Brain Dis. 2005 Jun;20(2):105-13. doi: 10.1007/s11011-005-4148-4.
Various investigators using near infrared spectroscopy (NIRS) have reported differing patterns of cytochrome C oxidase (cytochrome a,a3) redox status in similar brain oxygenation studies. We investigated whether distinctive differences could be due to combinations of variations in temperature, hematocrit, pH, and glucose.
Thirty-six healthy 10 kg commercial juvenile swine on cardiopulmonary bypass underwent 2-8 sequential periods of circulatory arrest. Prior to each arrest, key physiological variables were adjusted to match a random selection of one of 81 combinations of high, normal, or low levels of hypothermia, hematocrit, pH, and serum glucose. In the course of the study, the combinations were repeated twice to yield 162 NIRS data sets.
The mean rate of change in net oxidized minus reduced cytochrome a,a3 redox status in the brain following 7.5 min of ischemia was 0.49 +/- 0.26 micromol L(-1) min(-1), and, the corresponding mean magnitude of change was -1.23 +/- 0.57 micromol L(-1). The rate of change was influenced by temperature but not by hematocrit, pH, or glucose, either singly or in combination.
The respiratory response in mitochondria during systemic circulatory arrest is significantly influenced by temperature.
在类似的脑氧合研究中，使用近红外光谱（NIRS）的不同研究人员报告了细胞色素C氧化酶（细胞色素a，a3）氧化还原状态的不同模式。我们研究了独特的差异是否可能是由于温度、血细胞比容、pH值和葡萄糖变化的组合所致。
36只体重10千克的健康商用幼猪在体外循环下经历了2 - 8个连续的循环停止期。在每次停止前，将关键生理变量调整为与81种高、正常或低温、血细胞比容、pH值和血清葡萄糖水平组合中的一种随机选择相匹配。在研究过程中，这些组合重复两次以产生162个NIRS数据集。
缺血7.5分钟后，大脑中净氧化减去还原的细胞色素a，a3氧化还原状态的平均变化率为0.49±0.26微摩尔·升⁻¹·分钟⁻¹，相应的平均变化幅度为 - 1.23±0.57微摩尔·升⁻¹。变化率受温度影响，但不受血细胞比容、pH值或葡萄糖单独或组合的影响。
全身循环停止期间线粒体中的呼吸反应受温度显著影响。
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