Wu Yiduo, Zhang Fenghua, Wang Yang, Krishnamoorthy Maheshkumaar, Roy-Chaudhury Prabir, Bleske Barry E, Meyerhoff Mark E
Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA.
Clin Chem. 2008 May;54(5):916-8. doi: 10.1373/clinchem.2007.102103.
The determination of reference intervals for the concentration of total S-nitrosothiols (RSNOs) in blood is a highly controversial topic, likely because of the inherent instability of these species. Most currently available techniques to quantify RSNOs in blood require considerable sample handling and multiple pretreatment steps during which light exposure is difficult to completely eliminate. We investigated the effect of brief light exposure on the stability of RSNO species in blood during the initial sampling process.
A novel amperometric RSNO sensor, based on an immobilized organoselenium catalyst at the distal tip of an electrochemical nitric oxide detector, was used to determine RSNO species in diluted whole blood without centrifugation or pretreatment. Porcine blood was collected into aluminum foil-wrapped syringes via a 12-inch butterfly needle tube assembly. Two blood samples were collected from the same animal -- one with the butterfly needle tubing wrapped in aluminum foil and one with the tubing exposed to ambient room light. The RSNO concentrations in these sequential blood samples were determined by a standard addition procedure.
Eight sets of measurements were made in 6 animals. Samples exposed to light yielded RSNO concentrations only 23.6% (7.2%) [mean (SD)] of the RSNO concentrations determined in samples that were shielded from light and obtained from the same animals.
These results suggest significant photoinstablity of RSNOs in whole blood and indicate the critical importance of proper light protection during sampling and processing of blood samples for the accurate determinations of endogenous RSNO concentrations.
血液中总S-亚硝基硫醇（RSNOs）浓度参考区间的确定是一个极具争议的话题，可能是因为这些物质具有内在的不稳定性。目前大多数用于定量血液中RSNOs的技术需要大量的样品处理和多个预处理步骤，在此期间难以完全消除光照。我们研究了在初始采样过程中短暂光照对血液中RSNOs稳定性的影响。
一种新型的安培型RSNO传感器，基于在电化学一氧化氮检测器尖端固定的有机硒催化剂，用于在不进行离心或预处理的情况下测定稀释全血中的RSNOs。通过12英寸蝶形针管组件将猪血收集到用铝箔包裹的注射器中。从同一头动物采集两份血样——一份将蝶形针管包裹在铝箔中，另一份针管暴露于室内环境光下。通过标准加入法测定这些连续血样中的RSNO浓度。
对6只动物进行了8组测量。暴露于光下的样品所测得的RSNO浓度仅为来自同一动物且避光样品中RSNO浓度的23.6%（7.2%）[平均值（标准差）]。
这些结果表明全血中RSNOs具有显著的光不稳定性，并表明在采集和处理血样以准确测定内源性RSNO浓度时，适当的光保护至关重要。
