Study on experimental model of coronary artery thrombogenesis and acute myocardial infarction: Changes in epicardial ECG,platelet function and biochemistry,and pathology

A model was produced for formation of coronary artery thrombosis and development of acute myocardial infarction (AMI) in experimental dogs (n= 8) by injuring endothelium of coronary artery with a steel wire, inserting a copper wire into the lumen, and producing local stenosis with a constrictor. The results showed that ST segment of epicardial ECG began to elevate 15–30 min after handling the coronary artery, platelets aggregation rate and plasma TXB₂ increased rapidly, plasma 6-k-PGF_1α did not change, platelets cGMP rose continuously, while platelets cAMP rose only at 60 min after handling the coronary artery. Histological findings confirmed the occurrence of artery thrombus and myocardial necrosis. The model may be helpful in investigating the whole process of activation of platelet, thrombogenesis and development of AMI, with the changes in biochemstry, structure, pathophsiology and ECG monitored during the period.     

Inhibitory Effects of Qushuanling Capsule (祛栓灵胶囊) on Thrombus Formation and Platelet Aggregation in Rats

Objective:To investigate the effects of Qushuanling Capsule（祛栓灵胶囊,QSLC） on thrombus formation and platelet aggregation in rats.Methods:Arteriovenous bypass,venous thrombosis,and middle cerebral artery thrombosis models were used in rats to investigate the anti-thrombotic effects of QSLC,a compound of nine Chinese herbs.The platelet aggregation induced by adenosine diphosphate（ADP）,thrombin or arachidonic acid（AA）,as well as the contents of thromboxane B₂（TXB₂） and 6-keto-prostaglandin F1α（6-keto-PGF1α） in rat plasma and aortic walls,were determined to investigate the possible mechanisms of the anti-thrombotic effects of QSLC.Results:After oral administration with QSLC for 7 days,arteriovenous bypass thrombosis was obviously suppressed compared with the model group,venous thrombosis was also obviously suppressed,rat behaviors were obviously improved,and brain infarct size as well as water content were also reduced.The platelet aggregation induced by ADP or thrombin was inhibited by QSLC,but the drug had no effect on AA-induced platelet aggregation and content of TXB₂ and 6-keto-PGF1αin plasma and the aortic wall.Conclusion:These results suggest that QSLC can be used in the prevention and treatment of thrombotic diseases,and that its mechanism of action may be related to inhibition of platelet aggregation.     

Effects of oenethera biennis oil on plasma lipid, thromboxane A2 and angiotensin II of chronic renal insufficiency

Oenethera biennis oil was administered (6 g per day) in 23 chronic renal insufficiency patients over a 4 week period. Changes of serum creatinine, creatinine clearance, plasma lipid, renin activity, and angiotensin II, urinary thromboxane B₂ and 6-keto-prostaglandin F_1α were observed before and after the treatment. Results showed that after treatment, the creatinine clearance increased, serum total cholesterol, triglyceride and low density lipoprotein decreased, high density lipoprotein increased, plasma renin activity, angiotensin II and urinary thromboxane B₂ decreased significantly. The conclusion was that Oenethera biennis oil could improve the pathological process of renal diseases, and has beneficial effects on plasma lipid disorder and glomerular hemodynamics.     

Study on therapeutic mechanism of Neiyifang in treating endometriosis

Objective: To observe the clinical effect of Neiyifang (NYF) in treating endometriosis and to explore its therapeutic mechanism through observing its influence on plasma β-endorphin (β-EP) in different menstrual stages and levels of prostaglandins (PGs) in menstruation.Methods:NYF was administered to 104 patients with endometriosis one dose daily with 3 successive menstrual cycles as one therapeutic course. Peripheral blood β-EP level in follicular, luteal and menstrual stages, as well as PGF_2α, PGE2, thromboxane B₂ and 6-keto-PGFl α levels in menstrual stage were detected by RIA, and controlled with those in 15 healthy persons.Results: (1) The total effective rate of NYF was 81.3% and it showed significant effect in improving patients’ clinical symptoms and physical signs; (2) In menstrual stage, the levels of β-EP, 6-keto-PGF_α/ TXB₂ were lower(P <0.05) and levels of PGF_2α, PGE₂, TXB₂ and 6-keto-PGF_1α were higher (P< 0. 05) in patients than those in control, and the higher the level of PGE₂, the severer the menalgia, (3) NYF could increase levels of β-EP, 6-keto-PGF_1α, and reduce levels of PGF_2α, PGE_2α in menstrual stage of patients (all P<0.05).Conclusion: (1) NYF has good clinical effect in treating endometriosis; (2) Patients’ symptom of menalgia is closely related with the excessive high levels of PGF_2α and PGE₂, PGI₂/TXA₂ ratio disturbance, and excessive low level of β-EP; (3) NYF could significantly decrease the PGE₂, PGF_1α levels, increase the 6-keto-PGF_1α/TXB₂ ratio and the level of β-EP, so as to alleviate the menalgia in patients with endometriosis. This item was supported by National Funds of Natural Sciences(No. 30070942)     

Inhibitory effect of panicoin on platelet activation and its mechanism

Inhibitory Effect of Panicoin on Platelet Activation and Its Mechanism@韩谷鸣$Xuzhou Geriatrics Institute!Jiangsu 221003 @姚倩$Xuzhou Geriatrics Institute!Jiangsu 221003 @李洪莲$Xuzhou Geriatrics Institute!Jiangsu 221003     

Effect of buyang huanwu decoction on plasma thromboxane b2, 6-keto-prostaglandin f1α, endothelin and calcitonin gene related peptide in primary nephrotic syndrome patients

Objective: To explore the mechanism of Buyang Huanwu Decoction (BYHWD) in treating primary nephrotic syndrome (PNS).Methods: Based on the treatment of prednisone acetate and cytoxan, two groups of PNS patients were treated with aspirin and persantin (western medicine group, WM, 35 patients) and BYHWD plus WM (TCM-WM group, 35 patients) respectively. The effect on anticoagulation was observed and compared. Plasma levels of thromboxane B₂ (TXB₂ ), 6-keto-prostaglandin F_1α (6-K-PGF_1α), endothelin (ET), calcitonin gene related peptide (CGRP) were determined before and after treatment, at the reducing dose and shifting to maintenance dose of prednisone. The therapeutic effect of the two groups were also observed. Another group of 30 healthy subjects was established for control.Results: The differences of TXB₂, 6-K-PGF_1α, ET and CGRP between patients and healthy subjects were very significant before treatment (P < 0. 001). The above-mentioned 4 parameters improved synchronously with the clinical improvement in the therapeutic course and they were better in the TCM-WM group than those in the WM group (P < 0.001 ), and the complete remission rate of the former group was also higher than that of the latter (62.9 % vs 37.1 %, χ² = 4.63, P < 0.05).Conclusion: BHD could improve the therapeutic effect in treating PNS through the mechanism of improving TXB₂, 6-K-PGF_1α, ET and CGRP levels.     

毛冬青甲素和硝酸甘油对花生四烯酸代谢的影响

本文主要研究了毛冬青甲素在体外及体内对活化血小板功能途径的二磷酸腺苷(ADP)诱导的血小板聚集的抑制作用及与前列环素(PGI_2)样物质的作用。提示毛冬青甲素在体内能抑制活化血小板功能途径的花生四烯酸(AA),同时在体内及体外能抑制ADP活化血小板功能的途径。采用放射免疫法测定了兔血浆中血小析噁A_2(TXA_2)和PGI_2代谢物TXB_2及6—keto—PGF_(1α)的水平。结果提示毛冬青甲素可能主要是通过促进动脉内皮生成前列环素,而产生其抗血栓作用的。     

Follow-up efficacy of integrative Chinese and Western drugs on localized scleroderma with vitamine B6 and Xuefu Zhuyu Decoction

Objective: To investigate the therapeutic effects of vitamine B₆ (Vit B₆) and Xuefu Zhuyu Decoction (XFZY, for activating blood circulation to remove stasis) in patients with localized scleroderma(LSD).Methods: Thirty-three patients were treated with XFZY and Vit B₆, with 15 cases taking orally prednisone acetate and 20 healthy volunteers as the control. Their level of soluble interleukin-2 receptor (sIL-2R) and tumor necrosis factor-α (TNF-α) in the patients with LSD before and after treatment were observed.Results: The level of sIL-2R and TNF-α in the serum from the patients with LSD were higher than those of healthy volunteers (P<0.01). After treatment with Vit B₆ and XFZY, the level of sIL-2R and TNF-α from the patients with LSD decreased significantly (P<0.01), but there were no difference between the group taking Vit B₆ plus XFZY and the group given prednisone.Conclusion: The activating blood circulation to remove stasis approach in treating LSD with integrative Chinese and Western drugs got better results, and metabolic disorder of tryptophan might be correlated with the etiology of LSD.     

Postconditioning＇s Protection of THSG on Cardiac Ischemia-reperfusion Injury and Mechanism

Summary 2,3,5,4′-tetra-hydroxystilbene-2-O-glucoside (THSG), the water-soluble active components extracted from dried tuber root ofPolygonum multi florum (Polygonaceae), can promote the release of nitric oxide (NO) from vascular endothelial cells and has strong antioxidation. The post-conditioning's protection of THSG on cardiac ischemia-reperfusion injury and the mechanism were investigated. After reperfusion for 3 h following occlusion of rat left anterior descending coronary artery (LAD) for 30 min. SαT recovery speed, arrhythmia and cardiac infarct size were observed. The ischemic size and infarct size was identified by using Evans blue and TTC staining methods re-spectively. The results showed that the infarct size in THSG 7. 5 mg/kg postconditioning group was significantly decreased from 43.6%±9.1% in mode group to 16.5%±6.5% (P<0.01). SαT recovery was quicker and the incidence of arrhythmia (55.6% vs 100%,P<0.05) was significantly lower than in control group. The infarct size in THSG+glybenclamide group was greater than in THSG group, but equivalent to that in control group (46.8%±9.8% vs 43.6%±9.1%,P>0.05), SαT recovery speed slower and the incidence of arrhythmia also lower (33.3% vs 100%,P<0.01), suggesting that glybenclamide could abolish the effects of THSG postconditioning reducing the cardiac infart size. It was concluded that THSG administration before reperfusion could effectively alleviate the cardiac reperfusion injury and possessed the postconditioning effects of reducing cardiac infarct size, which might be related with the K_ATP channel opening. YE Shaojian, female, born in 1963, Associate Professor, M. D., Ph. D.     

Dynamic Expression of Tumor Necrosis Factor-α and Vascular Endothelial Growth Factor in Rat Model of Pulmonary Emphysema Induced by Smoke Exposure

In order to explore the roles of tumor necrosis factor-α(TNF-α) and vascular endothelial growth factor(VEGF) in the pathogenesis of pulmonary emphysema,male Wistar rats were randomized into group A1,group A2.5 and group A4,each with smoke exposure for 1 month,2.5 months or 4 months,respectively.Group B1,group B2.5 and group B4 were used as non smoking controls at corresponding time points.TNF-α in bronchoalveolar lavage fluid(BALF) and expression of VEGF in lung tissue was determined by ELISA or by SABC immunohistochemistry assay either.Lung slices were stained with hematoxylin and eosin(HE).Results showed that in animal with smoke exposure the mean linear interceptor(Lm),an index of pulmonary emphysema and the content of TNF-α in BALF increased gradually,on contrary,the expression of VEGF in lung tissue decreased(P<0.05).This phenomenon was not obvious in animals without smoke exposure.Lm was negatively correlated to the VEGF expression(γ=-0.81,P<0.01) and positively correlated to TNF-α concentration(γ = 0.52,P<0.004),which implies that smoke exposure decreased the expression of VEGF and increased the expression of TNF-α.It is plausible to speculate that the imbalance of TNF-α and VEGF may play an important role in the pathogenesis of smoke-induced pulmonary emphysema.     

Effects of propranolol on β- Adrenergic receptor of experimental acute myocardial infarction in rats

Summary By using receptor autoradiography to observe the distribution and density of receptors, the effects of propranolol, a β-blocker, on β-adrenergic receptor of experimental acute myocardial infarction (AMI) were studied. One week after ligation of proximate left anterior descend (LAD) coronary artery, [³H] DHA binding sites were markedly decreased in both infarctregion and non-infarct region. After treatment of propranolol (100 μg/kg), the [³H] DHA binding sites were obviously increased in the infarct region, and they were further decreased in the non-infarct region. The ratio of [³H] DHA binding sites of the infarct region to non-infarct region was from 0. 24 at LAD ligation to 0. 87 after propranolol treatment, which was close to 0. 97 of control group (sham operation). The results indicated that the propranolol acted directly on myocardial β- adrenergic through the receptor regulation of the balance of β-receptors between the infarct region and non-infarct region, and improvement of the myocardial consonation and contraction synergism, thereby protecting the heart affected by AMI.     

Effects of microinjection of L-glutamate into locus coeruleus complex area on respiration

Summary The experiments were performed on 55 rabbits vagotomied, anesthetized with urethane and immobilized with flaxedil. Injection of L-glutamate (L-glu) into the locus coeruleus complex (Lc-Sc) area led to a marked increase in respiratory frequency (RF) and phrenic nerve discharge rate (phr. d) (16±3.5% and 6.5±2.5%;P<0.01 andP<0.05, respectively), a decrease in inspiratory and expiratory duration, and no obvious change in blood pressure (Bp) was observed. While prazosin (0.5 μg/μl), yohimbin (4 (μg/μl) and propranolol (2μg/μl) were preinjected into the nuclei tractus solitraii (NTS) respectively, the above-mentioned effects of L-glu on respiration was blocked. These results indicate that the excitation of neurons in the Lc-Sc can induce an increase in RF and phr d and the excitative effect of L-glu on RF was mediated by α₁,α₂ and β-receptors in the NTS, while the effect on phrd was mediated differently. This project was supported by grant no. 3870190 from the National Natural Sciences Foundation of China.     

Effect of Cigarette Smoke Extract on the Role of Protein Kinase C in the Proliferation of Passively Sensitized Human Airway Smooth Muscle Cells

Cigarette smoke(CS) is ani mportant risk fac-tor involvedin the development and progression ofasthma[1]. Ovalbumin ( Ova) sensitization inducesairway hyperresponsiveness ( AHR) to inhaled CSin guinea pigs[2]. Airway smooth muscle prolifera-tion plays an i mportant role in airway remodelingin asthma . Protein kinase C (PKC) is one of thecrucial kinases in the intracellular signal transduc-tion pathway .CSEcanincrease PKC's activationinhuman bronchial epithelial cells[3].Because airwaysm…     

Clinical implication of the changes of cAMP,TXA<Subscript>2</Subscript> and PGI<Subscript>2</Subscript> in CSF of asphyxiated newborns

Summary To evaluate the changes of 3′, 5′-cyclic adenosine monophosphate (cAMP), thromboxane A₂(TXA₂) and prostacyclin (PGI₂) in cerebrospinal fluid (CSF) in the asphyxiated newborn and explore their roles in hypoxic-ischamic brain damage (HIBD). Thirty-six full term newborns were divided into 3 groups, including 12 with moderate-severe hypoxic-ischaemic encephalopathy (HIE), 13 with mild HIE, 11 without HIE (control group). The levels of cAMP, TXB₂ (TXA₂ metabolite) and 6-keto-PGF_1α (PGI₂ metabolite) in CSF and plasma were measured 36–72 h after birth by RIA, and the concentrations were expressed as nM/L (cAMP), ng/L(TXB₂ and 6-keto-PGF_1α). The infants were followed-up at 6 and 12 month of age and Mental Development Index (MDI) and Psychomotor Development Index (PDI) were measured using Bayley Scales of Infant Development (BSID). The CSF cAMP level in moderate-severe HIE group was 8.60±2.40, significantly lower than that of the mild HIE group (14.83±2.84) and the control group (24.43±2.39) (for bothP<0.01). The levels of TXB₂ and 6-keto-PGF_1α in CFS in the moderate-severe HIE group (206.06±29.74, 168.47±23.02, respectively) were significantly higher than in the mild HIE group (83.37±28.57, 131.42±16.57, respectively,P<0.01) and the control group (41.77±21.58, 86.23±13.05, respectively,P<0.01). The level changes of cAMP, TXB₂ and 6-keto-PGF_1α in plasma in all groups were similar to those in CSF, but no significant difference was found between mild HIE group and the control group (P>0.05). The follow-up results showed that MDI and PDI of the moderate-severe HIE group were the lowest (84.79±13.34, 83.50±13.28, respectively), followed by mild HIE group (102.19±7.02, 99.94±9.08, respectively), with the control group being the highest (116.63±12.08, 116.69±10.87, respectively). Univariate analysis showed some significant difference (the moderate-severe HIE group vs. the mild HIE group or the control group,P<0.01; the mild HIE group vs. the control groupP<0.05). The results suggested that the concentration of cAMP, TXA₂ and T/K ratio in CSF after neonatal asphyxia might be sensitive markers in evaluating the severity of brain damage in early stage and predicting the future outcome. LIU Hanchu, male, born in 1959, Associate Professor     

Ischemia-reperfusion injury up-regulates Pim-3 gene expression in myocardial tissue

This study examined the effect of ischemia-reperfusion injury on the expression of Pim-3 gene in myocardial tissues and their underlying mechanism.Rat models of myocardial ischemia-reperfusion injury were established by ligating the left anterior descending coronary artery of the rats.A total of 30 SD male adult rats were randomly divided into 5 groups:group A (sham operation,n=6);group B (in which the rats were subjected to 15 min of ischemia by ligation of the left anterior descending coronary artery,n=6);group C (in which the rats received 30 min of ischemia,n=6),group D and group E (in which the left anterior descending coronary artery of the rats were ligated for 30 min and then reperfused for 30 min or 120 min,n=6 in each).The left ventricular tissues were removed immediately after the ischemia-reperfusion injury.Neonatal cardiomyocytes were cultured and treated with different concentrations of H 2 O 2 (0,5,10,20 μmol/L) or tumor necrosis factor-α (TNF-α,0,1,5,10 ng/mL).The mRNA and protein expression of Pim-3 gene was determined by using RT-PCR,western blotting and immunohistochemistry.Additionally,neonatal cardiomyocytes were transfected with Pim-3 siRNA,and induced to develop apoptosis by using H 2 O 2.The results showed that normal myocardial tissues expressed a quantity of Pim-3 gene mRNA and protein.Ischemia-reperfusion injury could up-regulate the mRNA and protein expression of Pim-3 gene in myocardial tissues.Furthermore,H 2 O 2 but not TNF-α up-regulated the Pim-3 gene expression in cultured cardiomyocytes.And Pim-3 silencing failed to strengthen the H 2 O 2-inducing apoptosis in cardiomyocytes.It was concluded that ischemia-reperfusion injury up-regulated the Pim-3 gene expression through oxidative stress signaling pathway in myocardial tissues.     

Comparative study on effect of panax notoginseng and ticlid in treating early diabetes nephropathy

Ｄｉａｂｅｔｉｃｎｅｐｈｒｏｐａｔｈｙ（ＤＮ）ｉｓａｃｏｍｍｏｎｃｏｍｐｌｉｃａｔｉｏｎｏｆｄｉａｂｅｔｅｓｍｅｌｌｉｔｕｓ．Ｔｈｅｐａｔｈｏ ｇｅｎｅｓｉｓｏｆＤＮ ｇｌｏｍｅｒｕｌａｒｈｅｍｏｄｙｎａｍｉｃｓａｎｄｋｉｎｉｎ ｐｒｏｓｇｌａｎｄｉｎ ｒｅｇｕｌａｔｏｒｙｄｉｓｔｕｒｂａｎｃｅｉｓｃｌｏｓｅｌｙｒｅｌａｔｅｄ．Ｗｅａｄｏｐｔｅｄｒａｎｄｏｍｉｚｅｄｃｏｎ ｔｒｏｌｌｅｄｍｅｔｈｏｄｔｏｏｂｓｅｒｖｅｔｈｅｅｆｆｉｃａｃｙｏｆＴｉｃｌｉｄａｎｄＸｕｅｓｈｕａｎｔｏｎｇ（血栓通,Ｐａｎ…     

Changes of TXA_2 and PGI_2 during Postoperative Hypertensive Crisis in Patients with Hypertensive Intracerebral Hemorrhage

In order to explore the changes and the roles of TXA2 and PGI2 during postoperative hypertensive crisis in patients with hypertensive intracerebral hemorrhage, 31 cases subject to crani-otomy were divided into three groups: group A, 9 patients with postoperative hypertensive crisis; group B, 13 patients without postoperative hypertensive crisis; and group C, 9 patients without his-tory of hypertension and hypertensive intracerebral hemorrhage. TXA2, TXB2, 6-keto-PGF1α and PGI2 were measured after operation in the three groups respectively. The postoperative blood pres-sure in group A, including SBP and DBP, was elevated more obviously than that in the other two groups. TXA2 and PGI2 in group A were significantly higher than those in other two groups (P<0.01). Moreover, the ratio of TXB2 to 6-keto-PGF1α in group A was significantly higher than that in other two groups (P<0.05). The increase of TXA2 and the relative inadequacy of prostacyclin, especially 6-keto-PGF1α, may play roles in the postoperative hypertensive crisis. And the increased value of TXB2 to 6-keto-PGF1α could provide the basis for diagnosis of postoperative hypertensive crisis.     

Redistribution of platelet membrane glycoprotein iv and release of intracellular α-granule thrombospondin in patients with chronic myelogenous leukemia

Summary The redistribution of platelet membrane glycoprotein IV (GPIV) and the release of intracellular α-granule thrombospondin (TSP) were examined and the inhibition of β-thromboglobulin (β-TG) and platelet factor 4 (PF4) in patients with chronic myelogenous leukemia (CML) was observed and quantitation of β-TG and PF4 in sera was conducted. GPIV in inactive platelet from CML was 36080± 17010 molecules/platelet as compared with 13190±4810 from the controls (P< 0.01). No abnormality was found in the distribution of platelet membrane GPI_b and GPII_b/III,(P> 0.05). The GPIV redistribution on active platelet membrane induced thrombin (IU/ml) from CML and healthy donors was 44320 ±32310 and 22800± 12700 molecules/platelet respectively (P< 0.01). The difference in the release of intracellular α-granule TSP between CML and the control group was not found (P> 0.05). There was no direct correlation between GPIV expression and TSP binding after platelet activation. The high levels of β-TG and PF4 in sera inhibited release of intracellular α-granule TSPin vitro. These results indicate that the abnormality of platelet membrane GPIV is a common marker in CML, therefore the specific increase of platelet GPIV in patients with CML may be a useful tool for the diagnosis and monitoring of the platelet dysfunction. The release of internal TSP pools is hindered by either β-TG or PF4 in sera. This project was supported by the National Natural Science Foundation of China (No. 39370322).     

Experimental study of Yishou Tiaozhi tablet() on inhibiting hyperlipemia and atherosclerosis) on inhibiting hyperlipemia and atherosclerosis

Objective: To observe the effect of Yishou Tiaozhi tablet(YSTZT) on lipid metabolism and aortic intimal atherosclerotic plaque coverage in rabbit model of experimental hyperlipemia and atherosclerosis.Methods: Thirty-two rabbits were randomly divided into four groups, Group A, B, C and D, 8 in each group. Forage with cholesterol and lipid plus 1.59 g/kg of YSTZT was fed to Group A every day; for Group B, 22.54 mg/kg gypenoside tablet was added to forage with cholesterol and lipid; for Group C, hyperlipid forage was given and for Group D, only ordinary forage was given. Biochemical parameters were measured and pathomorpho-logical examinations were carried out 6 weeks later.Results: (1) YSTZT obviously lowered the levels of serum total cholesterol(TC), triglyceride(TG), atherosclerotic index(AI), apoprotein(ApoB), lipoprotein [Lp(a)], oxygen-low density lipoprotein cholesterol (ox-LDL), hydroxyproline(HYP), plasma Ca²⁺, thromboxane B₂ (TXB₂), and increased the levels of serum high-density lipoprotein cholesterol(HDL-C), apoprotein A₁ (Apo A₁), ApoA₁/ApoB, plasma 6-keto-PGF_lα (P < 0.01). (2) Pathomorphological examination showed that in Group A aortic intimal atherosclerotic plaque area and arterial intima thickness were obviously reduced, smooth muscle cell hyperplasia and elastic fibers were not seen.Conclusion: YSTZT can inhibit experimental hyperlipemia and atherogenesis. It is an ideal and effective medicine in preventing and treating hyperlipemia and atherosclerosis.     

Studies on IUD-induced menorrhagia and increased synthesis of prostacyclin in endometrium

Summary 43 samples of endometrium from IUD-users with excessive uterine bleeding (MBL>80 ml), normal menstrual blood loss (MBL< 80 ml) and non-IUD-users with normal menstrual blood loss (< 80 ml) have been studied. Concentration of 6-keto-PGF_1α, a metabolite of prostacyclin (PGI₂), was determined by radioimmunoassay. It was found that the concentration of 6-keto-PGF_1α of patients with IUD-induced excessive uterine bleeding was significantly higher than that of IUD-users with MBL less than 80 ml (P<0.05) and of non-IUD-users (P<0.01). But the difference between IUD-users with normal menstruation and the control was of no statistical significance (P>0.05). The results also indicated a positive correlation between the amount of MBL and 6-keto-PGF_1α concentration in endometrium of IUD-users (r = 0.439;P<0.05). The measurements of both tissue plasminogen. activator (t-PA) and 6-keto-PGI_1α concentrations from samples of 28 cases showed a weak positive correlation between t-PA and 6-keto-PGF_1α (r = 0.459;P<0.05). Further study is necessary to evaluate the significance of this result. In summary, our studies prove that the increased 6-keto-PGF_1α is an important factor contributing to excessive uterine bleeding in IUD-users.