Human Peritoneal Eosinophils and Formation of Arachidonate Cyclooxygenase Products

Human peritoneal eosinophils were obtained from the waste dialysis bags of patients undergoing continuous ambulatory peritoneal dialysis. The number of eosinophils obtained from each bag varied from 3 X 10(7) to 288 X 10(7). The cells were incubated for 1 h in tissue culture medium and prostaglandin E2 (PGE2), 6-keto-prostaglandin F1 (6-keto-PGF1), and thromboxane B2 (TXB2) were determined by radioimmunoassay of the supernatant. The basal release as well as the stimulated release from the purified eosinophils of TXB2 were five times greater than the release of PGE2 and thirty times greater than the release of 6-keto-PGF1. A dose-response curve was achieved for all three cyclooxygenase products with the calcium ionophore A23187. The release of TXB2 was inhibited in a dose-dependent manner by the specific thromboxane A2 (TXA2) synthase inhibitor OKY-1581 and a corresponding increase in PGE2 and 6-keto-PGF1 was obtained. Indomethacin (5.6 X 10(-6) M) inhibited the cyclooxygenase products to almost undetectable levels.     

Thromboxane A2 and prostacyclin release in bleeding time blood during primary haemostasis in healthy individuals

It is generally believed that prostacyclin (PGI2) generation is greatly stimulated when blood vessels are injured, even by minor trauma, such as venepuncture. The Simplate technique for measuring skin bleeding time was adapted to quantify by radioimmunoassay PGI2 and thromboxane A2 (TXA2) in the emerging blood, as the stable degradation products 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) and thromboxane B2 (TXB2), both of which were measured in venous plasma as well as in serum (clotted at 37 degrees C for 1 h). During bleeding, when platelets aggregate to occlude the injured vessels, the median TXB2 level in the emerging bleeding time blood was 1.7 ng/ml. The median TXB2 level in plasma was less than 1 ng/ml and in serum 275 ng/ml. The levels of immunoreactive 6-keto-PGF1 alpha were always below determination limit in bleeding time blood (0.2 ng/ml) and in plasma (0.1 ng/ml), whereas in serum the levels ranged between 0.26 and 0.47 ng/ml. The fact that enhanced PGI2 production in primary haemostasis in skin incisions could not be demonstrated calls for further investigations of possible PGI2 production with more sensitive assays or in injured large vessels.     

Relaxant and contractile effects of some amines and prostanoids in myometrial and vascular smooth muscle within the human uteroplacental unit

Tissue specimens of human myometrium and placenta were obtained at caesarean section and normal vaginal deliveries. Strips of myometrial tissue, and segments of intramyometrial arteries, chorionic plate arteries and veins, and stem villous arteries were dissected. The preparations were mounted in organ baths, and isometric tension was recorded. In myometrial preparations, prostaglandin F2 alpha (PGF2 alpha), prostaglandin E2 (PGE2), noradrenaline (NA) and serotonin (5-HT) all caused concentration-related contractions. In vascular preparations, the maximum contractant or relaxant effect, Emax or Imax, and the drug concentrations causing half maximum responses, EC50 or IC50 were determined. In intramyometrial arteries no significant differences between Emax or EC50 values were found for NA, 5-HT and PGF2 alpha. The Imax values (relaxation of vessels contracted by vasopressin) ranged prostacyclin (PGI2) greater than PGF2 alpha = PGE2, and the IC50 values PGF2 alpha = PGE2 = PGI2 (PGF2 alpha less than PGI2). Thus, PGF2 alpha showed dual effects. Only PGI2 relaxed placental vessels contracted by PGF2 alpha. In chorionic arteries, Emax values ranged PGE2 = PGF2 alpha greater than 5-HT greater than NA, and IC50 values 5-HT less than NA = PGF2 alpha = PGE2. In stem villous arteries, Emax ranged PGE2 = PGF2 alpha greater than 5-HT = NA, and EC50 5-HT = NA = PGE2 = PGF2 alpha. In chorionic veins the order of Emax values was PGF2 alpha = PGE2 greater than 5-HT greater than NA, and that of the EC50 values 5-HT less than NA = PGF2 alpha = PGE2. Smooth muscle tissues from the human uteroplacental unit show individual responses to prostanoids and amines, probably reflecting individual mechanisms for control of contractile activity and blood flow.     

羊水与自体血培养后刺激花生四烯酸代谢物的释放

目的：探讨人羊水在体外刺激自体血细胞释放前列环素（PGI₂）、血栓素A₂（TXA₂）和白三烯C₄（LTC₄）等花生四烯酸代谢物的作用。方法：取产妇羊水与自体血进行培养,用放射免疫分析法检测血中血栓素B₂（TXB₂）和6-酮前列腺素F_1α（6-Keto-PGF_1α）的含量,用酶联免疫法检测LTC₄。结果：羊水能刺激血细胞释放TXA₂和LTC₄,胎粪污染的羊水作用更为明显。TXB₂的含量由加羊水培养前的(63.5±52.0) ng/L增加到培养后的(189.1±102.0) ng/L（P<0.01）,用胎粪污染羊水与血培养后增加到(289.2±113.2) ng/L（P<0.01）;LTC₄的含量由培养前的(40.1±39.7) ng/L增加到培养后的(293.5±206.1) ng/L（P<0.01）,胎粪污染组增加到(387.2±214.6)ng/L（P<0.01）,但前列环素仅有轻度增加,无显著性差异(P>0.05)。结论：羊水能刺激血细胞释放花生四烯酸类生物活性物质,使其正常的平衡状态被破坏,可能与羊水栓塞的发生机理有关。     

Correlation of the directly observed responses of mesenteric vessles of the rat to nerve stimulation and noradrenaline with the distribution of adrenergic nerves

1. The effects of nerve stimulation and of the topical application of noradrenaline on arteries, capillaries and veins of the mesentery of the anaesthetized rat were examined by direct observation under a microscope. The distribution of adrenergic nerves to the vessels of the mesentery was studied using the fluorescence histochemical method.2. Principal arteries, small arteries and terminal arterioles were all innervated by a network of adrenergic fibres and they all constricted in response to the stimulation of paravascular nerves and to exogenous noradrenaline. Few adrenergic fibres accompanied the smaller, precapillary arterioles; these vessels did not respond to nerve stimulation, although they were constricted by concentrations of noradrenaline as low as 10(-10) g/ml.3. The capillaries did not respond to nerve stimulation or to applied noradrenaline. All veins were constricted by noradrenaline, but only those veins greater than about 30 mum in internal diameter responded to nerve stimulation.4. At stimulus frequencies greater than 4 Hz the flow of blood through the microvasculature usually ceased, although there was never complete closure of these vessels. The maximum constriction observed in principal arteries was usually between 50 and 70% of the control internal diameter, and in small arteries and terminal arterioles was between 40 and 65% of the control internal diameter.5. It is concluded that the principal arteries and small arteries of the mesenteric vasculature are important in the control of blood flow through this vascular bed during sympathetic stimulation and following topical application of noradrenaline, and that the precapillary arterioles are important vessels determining the rate of blood flow through the capillary bed under resting conditions.     

Pulmonary microvascular responses to inhaled prostacyclin, nitric oxide, and their combination in anesthetized cats

Using an X-ray television system on anesthetized cats, we directly measured internal diameter (ID) changes in identical small pulmonary vessels (100-1,100 microm ID) in response to inhalations of 25, 250, and 2,500 ng/kg/min aerosolized prostacyclin (PGI2), 4 and 34 ppm nitric oxide (NO), and the combination of aerosolized PGI2 and NO. We also compared ID changes during 250 ng/kg/min PGI2 inhalation both with and without an Nomega-nitro-L-arginine methyl ester (L-NAME, 30 mg/kg I.V.) pretreatment. In the arteries, inhaled PGI2 increased 100-900 microm vessel ID in a dose-dependent manner but caused no significant, or only slight, ID increases in the vessels larger than this. The greatest ID increase ( approximately 22%) was in the 100-500 microm arteries in response to 2,500 ng/kg/min PGI2 inhalation. PGI2 also increased the ID of the veins (6-12%), but the results were not dose related. NO inhalation also resulted in non-uniform ID response patterns similar to PGI2 with no significant, or only minimal, ID increases of the arteries >900 microm. The simultaneous inhalation of 2,500 ng/kg/min PGI2 and 34 ppm NO increased the arterial ID (maximum approximately 34%) more than either drug alone and to almost the same extent as brought about by injected papaverine (2 mg/kg), a smooth muscle relaxant. Inhaled PGI2 (250 ng/kg/min) decreased pulmonary arterial pressure and increased arterial ID to nearly the same extent with or without L-NAME pretreatment. These results indicate that inhaled PGI2 and inhaled NO locally dilate 100-900 microm pulmonary arteries in a dose-dependent manner and with a similar ID response pattern, and that the combination of these drugs produces a more enhanced vasodilator effect compared to their separate effects and induces the maximum dilated states. The data also suggest that inhaled PGI2 dilates these arteries directly, rather than via secondary release of endogenous NO.     

Difference between endothelium-dependent relaxation in arterial and in venous coronary bypass grafts

Both the internal mammary artery and the saphenous vein are used to construct coronary-artery bypass grafts. We hypothesized that the release or production of endothelium-derived relaxing factor, which regulates blood flow and inhibits platelet function, may differ in venous and arterial grafts. We therefore studied endothelium-dependent relaxation in internal mammary arteries, internal mammary veins, and saphenous veins obtained from 58 patients undergoing coronary bypass surgery. Vascular rings with and without endothelium were suspended in organ chambers, and isometric tension was recorded. Acetylcholine (10(-8) to 10(-4) M), thrombin (1 U per milliliter), and adenosine diphosphate (10(-7) to 10(-4) M) evoked potent endothelium-dependent relaxation in the mammary artery but weak response in the saphenous vein (P less than 0.005; n = 6 to 27). In the mammary artery, relaxation was greatest in response to acetylcholine (86 +/- 4 percent reduction in norepinephrine-induced tension), followed by thrombin (44 +/- 7 percent) and adenosine diphosphate (39 +/- 8 percent). In the saphenous and mammary veins, relaxation was less than 25 percent. Relaxation was unaffected by indomethacin but was inhibited by methylene blue and hemoglobin (P less than 0.005 and 0.01, respectively), which suggests that endothelium-derived relaxing factor was the mediator. Endothelium-independent relaxation in response to sodium nitroprusside was similar in arteries and veins. We conclude that endothelium-dependent relaxation is greater in the mammary artery than in the saphenous vein. The possibility that this contributes to the higher patency rate among arterial grafts than among venous grafts will require further study.     

Correlation of the directly observed responses of mesenteric vessels of the rat to nerve stimulation and noradrenaline with the distribution of adrenergic nerves

1. The effects of nerve stimulation and of the topical application of noradrenaline on arteries, capillaries and veins of the mesentery of the anaesthetized rat were examined by direct observation under a microscope. The distribution of adrenergic nerves to the vessels of the mesentery was studied using the fluorescence histochemical method.

2. Principal arteries, small arteries and terminal arterioles were all innervated by a network of adrenergic fibres and they all constricted in response to the stimulation of paravascular nerves and to exogenous noradrenaline. Few adrenergic fibres accompanied the smaller, precapillary arterioles; these vessels did not respond to nerve stimulation, although they were constricted by concentrations of noradrenaline as low as 10^-10 g/ml.

3. The capillaries did not respond to nerve stimulation or to applied noradrenaline. All veins were constricted by noradrenaline, but only those veins greater than about 30 μm in internal diameter responded to nerve stimulation.

4. At stimulus frequencies greater than 4 Hz the flow of blood through the microvasculature usually ceased, although there was never complete closure of these vessels. The maximum constriction observed in principal arteries was usually between 50 and 70% of the control internal diameter, and in small arteries and terminal arterioles was between 40 and 65% of the control internal diameter.

5. It is concluded that the principal arteries and small arteries of the mesenteric vasculature are important in the control of blood flow through this vascular bed during sympathetic stimulation and following topical application of noradrenaline, and that the precapillary arterioles are important vessels determining the rate of blood flow through the capillary bed under resting conditions.

     

Characterization of the prostanoid receptors and of the contractile effects of prostaglandin F2 alpha in human pial arteries

The contractile and relaxant effects of various prostanoids were studied on isolated human pial arteries. Contractions were elicited with the following order of potency: U46619 approximately equal to U44069 greater than PGB2 greater than PGF2 alpha greater than PGE2 approximately equal to PGD2 approximately equal to PGF1 alpha greater than or equal to TXB2, indicating that prostanoid-induced contractions probably are mediated by a thromboxane-sensitive receptor. Relaxation of PGF2 alpha-contracted arteries was induced with the order of potency: PGE2 greater than PGE1 greater than PGD2 approximately equal to PGD1. Vessels contrated by K+ were relaxed only by PGE1. Since PGI2 was previously found to be more potent than all the prostanoids tested in the present study, relaxant responses are probably mediated via a PGI2-sensitive receptor. The role of free extracellular and cellularly bound calcium for the contractile effects of PGF2 alpha and K+ were estimated by incubating the arteries for various times in calcium-free medium containing 10(-5) M EGTA. Incubation for 5-10 min abolished K+-induced contractions, whereas after 40 min of incubation PGF2 alpha still induced contractions that reached 70% of control. The PGF2 alpha-induced contraction was biphasic in 8 out of 10 preparations. The second phase could be eliminated by increasing the EGTA-concentration to 10(-4) M, as well as by nifedipine pretreatment. In calcium-free, high K+ medium calcium-induced contractions were elicited at lower concentrations in the presence of PGF2 alpha. The results suggest that PGF2 alpha-induced contractions in human pial arteries are relatively independent of free extracellular calcium. PGF2 alpha may promote trans-membrane influx of calcium, as well as release calcium from seemingly superficially located cellular stores.     

高血压患者血管内皮依赖性舒张功能失调的研究

目的 :观察不同程度高血压对血管内皮依赖性舒张功能失调的影响 ,并探讨其发生的可能机制。方法 :71例原发性高血压患者按照高血压程度分为Ⅰ、Ⅱ、Ⅲ级三组。另设正常血压对照组 3 0例。采用高分辨超声影像技术 ,测量肱动脉反应性充血前后血管内径和血流速度的变化。测定各组受试者反应性充血前后血浆NO、PGI2 、TXB2 、ET等血管活性物质。结果 :随高血压分级程度增加 ,肱动脉血管内皮依赖性舒张能力逐步变小 ,血浆NO、PGI2 逐渐下降 ,TXB2 、ET逐渐增高。结论 :随着高血压程度的加重 ,血管内皮依赖性舒张功能受损也加重 ,可能是由于内皮源性NO、PGI2 等舒张性因子合成释放减少而缩血管因子ET、TXB2 合成释放增加有关。     

Effects of lipid peroxides on prostacyclin and thromboxane generation in hypercholesterolemic rabbits

Rabbits fed an atherogenic diet for 60 days resulted in high levels of plasma lipid peroxides as well as extreme hypercholesterolemia. Both levels stayed high until 35 days after the atherogenic diet stopped. At the same time, plasma PGI2 level was remarkably decreased while TXA2 and platelet aggregability were increased. Atherosclerotic aortas contain high levels of lipid peroxides associated with decreased PGI2 and increased TXA2 generation. Atherosclerotic plaques had the highest level of lipid peroxides and TXA2 while PGI2 production was the least, as compared with nonplaque tissue of the same artery and the normal arteries. The condition of normal arteries was just the reverse. There was a negative correlation between lipid peroxides and prostacyclin production, and a positive correlation between lipid peroxides and TXA2, in both plasma and aorta of rabbits. These results suggest that there is a close correlation between atherosclerosis, elevated lipid peroxides, and disturbances in PGI2/TXA2 balances.     

妊高征中胎盘血管内皮生长因子的表达及其与胎盘释放血管活性物质的关系

目的 探讨胎盘血管内皮生长因子（ＶＥＧＦ）在妊高征中的表达及其与胎盘释放前列环素（ＰＧＩ２）、血栓素Ａ２（ＴＸＡ２）的关系。方法 分别采用蛋白免疫印渍（Ｗｅｓｔｅｒｎ ｂｌｏｔ）和放免技术测定２５例孕晚期正常妊娠（ＮＬＰ）及２５例妊高征（ＰＩＨ）患者的胎盘ＶＥＧＦ表达及胎盘和血浆中ＰＧＩ２、ＴＸＡ２水平。结果 与ＮＬＰ比较,ＰＩＨ组胎盘ＶＥＧＦ的表达显著降低（Ｐ〈０．０１）;胎盘组织及血浆中ＰＧＩ２水平及ＰＧＩ２／ＴＸＡ２显著下降（Ｐ〈０．０１）,ＴＸＡ２水平显著升高（Ｐ〈０．０１）;ＰＩＨ中胎盘ＶＥＧＦ表达与其产生的ＰＧＩ２、ＰＧＩ２／ＴＸＡ２呈显著正相关（Ｐ〈０．０１）,与ＴＸＡ２呈显著负相关（Ｐ〈０．０１）,并与临床收缩期血压（Ｐ〈０．０１）和舒张期血压（Ｐ〈０．０５）呈显著负相关。结论 胎盘ＶＥＧＦ下降     

脑益嗪和毛冬青甲素对大鼠动脉环产生前列环素和血小板释放血栓素A_2的影响

脑益嗪体内给药能显著地抑制血小板聚集,但对动脉环前列环素(PGI_2)的产生和血小板血栓素A_2(TXA_2)的释放无作用,其抗血栓形成的作用看来不是通过对TXA_2/PGI_2系统的影响而发挥的;毛冬青甲素静脉注射,非常显著地抑制血小板聚集、抑制血小板TXA_2的释放,但不影响动脉环PGI_2的产生,生物测定法和放射免疫分析法所得结果相平行,提示毛冬青甲素可能是一种血栓素A_2合成酶抑制剂。     

加速性肾毒性肾炎中肾小球血栓素A2受体变化的研究

目的：了解肾炎模型中肾小球血栓素（ＴＸ）Ａ２受体的变化并探讨其机制。方法：建立大鼠加速性肾毒性血清性肾炎模型。应用放免法测定肾小球产生的ＴＸＢ２,应用放射配体受体分析法及Ｗestern blot 分析法测定肾小球ＴＸＡ２受体。结果：肾炎鼠肾小球产生的ＴＸＢ２增多,肾小球ＴＸＡ２受体的最大结合容量（Ｂmax）及受体蛋白量减少。应用ＴＸ Ａ２合酶抑制剂furegrelate对肾炎鼠预处理,可抑制肾小球ＴＸＢ２的升高,可使ＴＸＡ     

Modulation of vascular tone and reactivity by nitric oxide in porcine pulmonary arteries and veins

Isolated porcine pulmonary vessels were studied in order to evaluate the role of nitric oxide in arteries and veins. Leukotriene C4 and noradrenaline contracted porcine pulmonary arteries but induced only negligible contractions of porcine pulmonary veins. After treatment with the nitric oxide synthase inhibitor N(omega)-nitro-L-arginine (L-NOARG), significant contractions to leukotriene C4 and noradrenaline were uncovered in pulmonary veins. In arterial preparations, L-NOARG caused a less marked potentiation of noradrenaline-induced contractions and did not alter leukotriene C4-induced contractions. Endothelium-dependent relaxations to acetylcholine were greater in veins compared with arteries whereas the endothelium-independent relaxations to the nitric oxide donor sodium nitroprusside (SNP) and the cyclic nucleotide analogue 8-bromo-cGMP were similar in the two preparations. Taken together these data suggest that the apparent insensitivity of porcine pulmonary veins to leukotriene C4 and noradrenaline was because of release of nitric oxide. The effect of nitric oxide synthase inhibition was less pronounced in porcine pulmonary arteries, suggesting a preferential functional role of nitric oxide in porcine pulmonary veins, originating in a greater production of nitric oxide by veins as opposed to arteries.     

肝硬化患者血浆PGI2和TXA2含量变化的临床意义

目的:观察肝硬化患者血浆中前列环素（PGI₂）和血栓素A₂（TXA₂）含量的变化,探讨其在肝病发生、发展中的临床意义。方法:选取2010年10月～2011年10月间云南省第三人民医院消化内科收治的肝硬化患者48例及健康体检正常者30例,采用放射免疫分析（RIA）分别测定其血浆中PGI₂和TXA₂的代谢产物6-酮-前列环素(6-Keto-PGF_1α)和血栓素B₂（TXB₂）的含量,进行统计学分析。结果:Child-Pugh分级A级患者血浆中6-Keto-PGF_1α和TXB₂含量分别为（108.8±34.2）ng/L和（87.5±19.3）ng/L,B级为（139.4±38.3）ng/L和（106.6±20.7）ng/L,C级为（181.9±53.2）ng/L和（128.5±26.3）ng/L,正常对照组为（90.6±23.6）ng/L和（73.6±18.3）ng/L,经方差分析,各组之间差异有统计学意义（F值分别为5.12,4.63,P均<0.01）;各组间经SNK-q检验比较,差异均有统计学意义（P均<0.01）;血浆中6-Keto-PGF_1α和TXB₂含量在Child-Pugh分级A、B、C级患者中逐级增高。结论:血浆PGI₂和TXA₂参与了肝硬化的发生、发展,动态监测PGI₂和TXA₂含量的变化有利于肝硬化患者病情的判断。     

Formation and action of prostacyclin in the isolated human umbilical artery.

The transformation of [1-14C]arachidonic acid by homogenates of human umbilical arteries was studied. The major compound formed was the stable end product of PGI2, i.e. 6-keto-PGF1 alpha (lactol form) as analyzed by gas-liquid chromatography-mass spectrometry. PGI2 was generated by incubating PGH2 with a lyophilized pig aorta microsome preparation. PGI2 concentrations around 10 ng/ml relaxed the human umbilical artery preparation significantly. Formation of PGI2 by umbilical arteries during pregnancy might be a mechanism for regulation of blood flow to the fetus.     

新生儿缺氧缺血性脑病患者血浆ET、TXA2和PGI2测定的临床意义

目的：探讨血浆内皮素（ET）、血栓素A2（TXA2）、前列环素（PG I2）在新生儿缺氧缺血性脑病发病中的作用。方法：应用放射免疫分析测定了33例缺氧缺血性脑病新生儿和30例正常新生儿血浆ET、TXB2、6-keto-PGF1α的含量。结果：缺氧缺血性脑病新生儿血浆ET、TXB2水平非常显著地高于正常新生儿组（P〈0.01）,而6-keto-PGF1α水平则显著地低于正常新生儿组（P〈0.01）;血浆ET水平与TXB2成正相关（r=0.6128,P〈0.01）,与6-keto-PGF1α水平负相关（r=-0.5011,P〈0.01）。结论：缺氧缺血性脑病新生儿血管内皮细胞存在内分泌功能紊乱、内皮素（ET）合成释放增加、前列环素（PG I2）水平降低、两者反馈调控失衡及ET与血栓素A2（TXA2）的协同作用在新生儿缺氧缺血性脑病的发病中具有重要的临床价值。     

Effect of sympathetic nerve stimulation and adrenoceptor blockade on pial arterial and venous calibre and on intracranial pressure in the cat

Pial arterial and venous calibre were continuously recorded through a closed cranial window preparation during cervical sympathetic nerve stimulation in 10 cats before and after alpha- and beta-adrenoceptor blockade. In addition, the intracranial pressure (ICP) was simultaneously recorded in 4 of the cats. Under resting conditions 33 arteries (mean diameter 130 micron) constricted by 11.7 +/- 0.8% and 80 venous portions (mean diameter 152 micron) constricted by 13.7 +/- 0.7% during sympathetic nerve stimulation. ICP decreased simultaneously by 16.5 +/- 6.2%. Administration of the alpha-adrenoceptor antagonist phenoxybenzamine i.v. (1.5 mg X kg-1) abolished the reduction of ICP and markedly reduced, but did not completely abolish, the constrictor response of arteries and veins. The beta-adrenoceptor antagonist propranolol (1.5 mg X kg-1) did not significantly alter the reduction of ICP or the response of pial veins and small arteries, whereas the response of arteries with a diameter greater than 150 micron was attenuated. It is concluded that the constriction of pial veins and arteries during sympathetic stimulation is mediated predominantly via alpha-adrenoceptors. The sympathetic nerves of cerebral blood vessels may have stronger influence on the cerebral capacitance than on resistance vessels under normotensive and normocapnic conditions.     

吸烟对血管内皮依赖性舒张功能的影响

目的 观察吸烟对和因管内皮依赖性舒张功能的影响,探讨吸烟对心血管危害的机制。