Mathieson M A, Dunham B M, Huval W V, Lelcuk S, Stemp L I, Valeri C R, Shepro D, Hechtman H B
Surg Gynecol Obstet. 1983 Dec;157(6):500-4.
Thromboxane A2 is thought to be an important mediator of cardiopulmonary dysfunction, hence stimuli that effect synthesis of this prostanoid are of major interest. In this study, the thesis that ischemia of the limb is a significant stimulus to thromboxane A2 synthesis and the generation of a circulating negative inotrope is tested. Twelve healthy volunteers, taking no medications and ranging in age from 21 to 29 years, underwent inflation of an arm cuff to either 70 or 220 millimeters of mercury for ten minutes. Immediately after deflation of the cuff from 220 millimeters of mercury, the stable degradation product of thromboxane A2, thromboxane B2, rose from a base line plasma level of 34 +/- 6 picograms per milliliter (mean +/- SEM) to 70 +/- 18 picograms per milliliter. In contrast, deflation from a cuff pressure of 70 millimeters of mercury resulted in a lower thromboxane B2 level of 26 +/- 9 picograms per milliliter (p less than 0.05). Plasma obtained before and after inflation of the cuff to 220 millimeters of mercury was used to bathe a rat papillary muscle. Developed tension fell from a base line of 2.80 +/- 0.19 to 2.44 +/- 0.17 grams (p less than 0.01). There was no significant change in developed tension induced by plasma harvested after the cuff was inflated to 70 millimeters of mercury. The base line plasma level of 6-keto-prostaglandin F1 alpha, the hydrolysis product of prostacyclin, was 46 picograms per milliliter; the plasma serotonin, 51 nanograms per milliliter; the platelet serotonin, 1.02 micrograms per 10(9) platelets; platelet count, 220,000 per cubic millimeter, and white blood count, 6,094 per cubic millimeter. These values did not change significantly with cuff inflation to either 220 or 70 millimeters of mercury. The results show that ischemia of the limb leads to thromboxane A2 production. Possible adverse cardiac effects related to this event are suggested by the bioassay demonstrating that circulating plasma with high levels of thromboxane B2 is associated with the depression of tension of an isolated rat papillary muscle.
血栓素A2被认为是心肺功能障碍的重要介质，因此影响这种前列腺素合成的刺激因素备受关注。在本研究中，对肢体缺血是血栓素A2合成的重要刺激因素以及产生循环负性肌力物质这一论点进行了验证。12名年龄在21至29岁之间、未服用药物的健康志愿者，将手臂袖带充气至70或220毫米汞柱并保持10分钟。当袖带从220毫米汞柱放气后，血栓素A2的稳定降解产物血栓素B2，从基线血浆水平每毫升34±6皮克升至每毫升70±18皮克。相比之下，袖带从70毫米汞柱放气后，血栓素B2水平较低，为每毫升26±9皮克（p<0.05）。将袖带充气至220毫米汞柱前后采集的血浆用于灌注大鼠乳头肌。收缩张力从基线的2.80±0.19克降至2.44±0.17克（p<0.01）。袖带充气至70毫米汞柱后采集的血浆所诱导的收缩张力无显著变化。前列环素的水解产物6-酮-前列腺素F1α的基线血浆水平为每毫升46皮克；血浆5-羟色胺为每毫升51纳克；血小板5-羟色胺为每10⁹个血小板1.02微克；血小板计数为每立方毫米220,000个，白细胞计数为每立方毫米6,094个。袖带充气至220或70毫米汞柱时，这些值均无显著变化。结果表明，肢体缺血会导致血栓素A2生成。生物测定表明，血栓素B2水平高的循环血浆与离体大鼠乳头肌张力降低有关，提示了与该事件相关的可能的不良心脏效应。
