Gussakovsky Eugene, Jilkina Olga, Yang Yanmin, Kupriyanov Valery
Institute for Biodiagnostics, National Research Council Canada, 435 Ellice Ave, Winnipeg, Manitoba, Canada R3B1Y6.
Anal Biochem. 2008 Nov 15;382(2):107-15. doi: 10.1016/j.ab.2008.07.028. Epub 2008 Jul 31.
To noninvasively determine absolute concentrations of hemoglobin (Hb) plus myoglobin (Mb) in cardiac tissue by means of regular near infrared (NIR) light diffuse reflectance measurements, a first derivative approach was applied. The method was developed to separately calculate oxygenated and deoxygenated [Hb+Mb] as well as an effective pathlength, which NIR light passes through in the tissue between optodes. Applying a cotton wool-based phantom, which mimics muscle tissue, it was shown that the intensity of the pseudo-optical density first derivative depends linearly on both oxygenated and deoxygenated Hb concentration, thereby validating the Lambert-Beer law in the range of 0 to 0.25 mM tetrameric Hb. A high correlation (R=0.995) was found between concentrations of Hb loaded onto the phantom and those determined spectrophotometrically, thereby verifying the first derivative method validity. The efficiency of the method was tested using in vivo pig hearts prior to and after ischemia initiated experimentally by left anterior descending artery branches occlusion. The results showed that the total [Hb+Mb] was 0.9-1.2 mM heme, the average tissue oxygen saturation was approximately 70% (which reduced to nearly 0% after occlusion), and the NIR (700-965 nm) light pathlength was 2.3 mm (differential pathlength factor [DPF]=2.7-2.8) in a living heart tissue.
为了通过常规近红外（NIR）光漫反射测量无创地确定心脏组织中血红蛋白（Hb）加肌红蛋白（Mb）的绝对浓度，采用了一阶导数方法。该方法旨在分别计算氧合和脱氧的[Hb+Mb]以及近红外光在光极之间的组织中穿过的有效光程。使用模拟肌肉组织的棉絮基模型，结果表明伪光密度一阶导数的强度与氧合和脱氧Hb浓度均呈线性关系，从而验证了朗伯-比尔定律在0至0.25 mM四聚体Hb范围内的有效性。在加载到模型上的Hb浓度与通过分光光度法测定的浓度之间发现了高度相关性（R=0.995），从而验证了一阶导数方法的有效性。在通过闭塞左前降支分支实验性引发缺血之前和之后，使用体内猪心脏测试了该方法的效率。结果表明，在活体心脏组织中，总[Hb+Mb]为0.9-1.2 mM血红素，平均组织氧饱和度约为70%（闭塞后降至近0%），近红外（700-965 nm）光程为2.3 mm（微分光程因子[DPF]=2.7-2.8）。
