Tumour cell u-PA as a cause of fibrinolytic bleeding in metastatic disease

Tumour cells may express urokinase type plasminogen activator (u-PA). This may influence the invasive properties of the cells but has seldom been implicated in production of a systemic bleeding state. Two patients are described in whom severe bleeding occurred in association with disseminated malignancies. Thrombin generation was little disturbed and platelet numbers were insufficient to account for the bleeding. Florid plasmin generation was evident in the circulation and the fibrinolytic inhibitor tranexamic acid controlled the bleeding well. Free active u-PA was demonstrated in the circulation and u-PA antigen on the malignant cells which invaded the marrow of one of the patients. Tumour cell u-PA may occasionally be responsible for a bleeding state.     

The bleeding disorder in acute promyelocytic leukaemia: fibrinolysis due to u-PA rather than defibrination

Three consecutive patients with acute promyelocytic leukaemia who presented with severe haemorrhagic syndromes were studied and the findings contrasted with those of two patients with classical defibrination after electroshock or complicated labour. The leukaemic patients showed no depletion of fibrinogen. There was no evidence of disordered thrombin generation by either intrinsic or extrinsic pathway sufficient to account for their haemorrhage. All, however, showed strikingly enhanced fibrinolytic activity, which could have accounted for bleeding. This fibrinolytic disorder was characterized by free u-PA in the plasma and differed from that seen after classical defibrination, where free t-PA was observed. U-PA was found also in malignant promyelocytes, which may be the source of u-PA activity in the patients' plasma. Bleeding in promyelocytic leukaemia may be primarily a fibrinolytic disorder.     

急性白血病并发出血患者的止凝血特点及其与预后的关系

目的：研究急性白血病(AL)并发不同程度出血患者的止凝血异常特点及其与预后的关系。方法：采用ELISA方法检测93例AL患者血浆组织因子(TF)、组织因子途径抑制物(TFPI)、凝血酶-抗凝血酶复合物(TAT)、纤溶酶-抗纤溶酶复合物(PAP)、尿激酶型纤溶酶原激活物(u-PA)、尿激酶型纤溶酶原激活物受体(u-PAR)、D-二聚体(D-D)的含量。结果：仅有TF、TAT、D-D升高者，临床上大多表现为轻度出血；除TF、TAT、D-D显著升高外，还伴有u-PA、u-PAR、PAP高于无出血对照组者，临床上以重度出血为主。TAT、PAP、D-D对弥散性血管内凝血前期(pre—DIC)诊断的灵敏度分别为88．57％、97．14％和85．70％，特异性为69．57％、76．09％和89．13％；联合应用三个指标，其灵敏度为80．OO％，特异性为95．65％。u-PA、u-PAR持续增高者预后差，2年无复发生存率(RFS)和2年总生存率(OS)显著降低。结论：轻度出血主要由高凝、继发性纤溶亢进等引起，而原发性纤溶亢进则是重度出血最主要的原因；TAT、PAP、D-D对pre—DIC的诊断有重要意义；多项分子标志物的联合应用可提高pre—DIC的确诊率。TF对DIC的发展和进程具有预示作用。u-PA、u-PAR可作为部分AL并发出血患者的预后判断指标。     

Effects of urokinase receptor occupancy on plasmin generation and proteolysis of basement membrane by human tumor cells.

The goal of the present study was to assess the relative importance of receptor-bound and secreted plasminogen activator urokinase (u-PA) in generating cell-surface plasmin and fostering destruction of normal tissue by tumor cells. We first showed that active site-inhibited u-PA could displace endogenous u-PA from the surface of the human colon adenocarcinoma cell line HCT 116. We then prepared expression vectors for u-PA and for a mutant molecule in which the codon for the active site serine residue was changed to encode alanine. Expression of non-functional mutant u-PA decreased the level of cell-bound active u-PA by more than 95% via a mechanism that involved competition for receptor sites. Decreased cell-surface u-PA activity was associated with a decrease in cell-bound plasmin activity to undetectable levels, suggesting that receptor-bound u-PA plays an important role in the generation of plasmin on the cell surface. Transfectants that secreted eightfold to 20-fold elevated levels of active wild-type u-PA showed approximately 50% increases in cell-associated u-PA and only twofold to fourfold increases in cell-associated plasmin, suggesting that the role of secreted u-PA in generating cell-surface plasmin activity was relatively minor. In parent cells and both types of transfectants there was a good correlation between the amount of plasmin bound to the tumor cell surface and the extent to which a basement membrane substrate was degraded. These studies show that receptor-bound u-PA provides an efficient mechanism for plasmin generation on the surface of tumor cells, which, in turn, contributes significantly to their degradative potential.     

Platelets from patients with the Quebec platelet disorder contain and secrete abnormal amounts of urokinase-type plasminogen activator.

The Quebec platelet disorder (QPD) is an autosomal dominant platelet disorder associated with delayed bleeding and alpha-granule protein degradation. The degradation of alpha-granule, but not plasma, fibrinogen in patients with the QPD led to the investigation of their platelets for a protease defect. Unlike normal platelets, QPD platelets contained large amounts of fibrinolytic serine proteases that had properties of plasminogen activators. Western blot analysis, zymography, and immunodepletion experiments indicated this was because QPD platelets contained large amounts of urokinase-type plasminogen activator (u-PA) within a secretory compartment. u-PA antigen was not increased in all QPD plasmas, whereas it was increased more than 100-fold in QPD platelets (P <.00009), which contained increased u-PA messenger RNA. Although QPD platelets contained 2-fold more plasminogen activator inhibitor 1 (PAI-1) (P <.0008) and 100-fold greater u-PA-PAI-1 complexes (P <.0002) than normal platelets, they contained excess u-PA activity, predominantly in the form of two chain (tcu-PA), which required additional PAI-1 for full inhibition. There was associated proteolysis of plasminogen in QPD platelets, to forms that comigrated with plasmin. When similar amounts of tcu-PA were incubated with normal platelet secretory proteins, many alpha-granule proteins were proteolyzed to forms that resembled degraded QPD platelet proteins. These data implicate u-PA in the pathogenesis of alpha-granule protein degradation in the QPD. Although patients with the QPD have normal to increased u-PA levels in their plasma, without evidence of systemic fibrinogenolysis, their increased platelet u-PA could contribute to bleeding by accelerating fibrinolysis within the hemostatic plug. QPD is the only inherited bleeding disorder in humans known to be associated with increased u-PA.     

Elevated urokinase-type plasminogen activator level and bleeding in amyloidosis: case report and literature review

Hyperfibrinolytic states are reported to be a cause of bleeding in patients with amyloidosis. We reviewed the literature on excessive fibrinolysis in association with amyloidosis and report our findings from a patient with idiopathic amyloidosis who developed a bleeding diathesis. Coagulation laboratory studies indicated elevated plasminogen activator levels associated with a reduction of plasminogen and alpha 2-plasmin inhibitor (alpha 2-PI) levels. The level of tissue-type plasminogen activator (t-PA) inhibitor and t-PA antigen were normal. However, the patient did have a five- to sevenfold increase in amidolytic activity for the urokinase substrate pyro-Glu-Gly-Arg-pNA (S-2444). This case therefore represents a novel example of a hyperfibrinolytic state associated with amyloidosis caused by elevated urokinase-type plasminogen activator (u-PA). Epsilon-amino caproic acid (EACA) therapy resulted in an increase in alpha 2-PI and plasminogen levels and effectively reduced the blood loss. Hyperfibrinolytic states in amyloidosis have now been reported to be due to elevated t-PA and u-PA and depleted t-PA inhibitor.     

Tumor necrosis factor induces the production of urokinase-type plasminogen activator by human endothelial cells

Endothelial cells play an important role in the regulation of fibrinolysis by the production of several key regulatory proteins. The cytokines tumor necrosis factor (TNF), lymphotoxin, and interleukin-1 (IL-1), but not interleukin-6, increase the production of plasminogen activator inhibitor-1 (PAI-1) by endothelial cells, whereas they have no stimulatory effect on the production of tissue-type plasminogen activator (t-PA). Primary cultures of human endothelial cells release very little urokinase-type plasminogen activator (u-PA). We report here that TNF and lymphotoxin induce, in a concentration-dependent way, the production of both cellular and secreted u-PA antigen in primary and subcultured human endothelial cells. The TNF-induced increase was accompanied by a more than 10-fold increase in u-PA mRNA. Upon stimulation of early passage umbilical vein endothelial cells by TNF, u-PA was predominantly secreted at the basolateral side, whereas PAI activity and t-PA were found in more equal amounts at the apical and basolateral sides of the cell monolayers. TNF-stimulated u-PA secretion by subcultured human aorta endothelial cells showed only a marginal polarity. The u-PA antigen was present in a plasmin-activatable form (single chain u-PA) and in a nonactivatable form (probably u-PA: PAI-1 complex). During the induction of u-PA by TNF, the ratio between plasmin-activatable u-PA and total u-PA decreased markedly. This may indicate that TNF also increases the degree of u-PA activation. The parallel induction of the synthesis and secretion of both u-PA and PAI-1 by endothelial cells adds a new aspect to the alterations of the fibrinolytic system caused by inflammatory mediators. This aspect may be significant for the regulation of cell-associated and interstitial plasminogen activator activity.     

Haemorrhage associated with large abdominal aortic aneurysms

Two patients are described who each had a major haemorrhage after minor surgery and who additionally had large abdominal aortic aneurysms. Neither had depletion of platelets or coagulation factors sufficient to account for bleeding. Both had grossly enhanced fibrinolytic activity with evidence of plasmin generation in the circulation. In one patient insertion of an aortic graft was rapidly followed by resolution of the fibrinolytic abnormalities. Overactive fibrinolysis, rather than coagulation factor consumption may account for some of the bleeding syndromes complicating abdominal aortic aneurysms.     

Platelet aggregation and coagulation and fibrinolysis parameters in both portal and systemic circulations in patients with cirrhosis and hepatocellular carcinoma

A tendency to bleed and local vasodilation in the portal circulation are exacerbatory clinical factors in patients with liver cirrhosis. Esophageal variceal bleeding, in particular, is a frequent complication in these patients. Cirrhotic patients have been reported to show impairment of platelet aggregation and an activated fibrinolytic state, possibly with consequential lengthening of the bleeding time. Our previous study has demonstrated enhanced generation of PGI₂, a vasodilating and anti-platelet aggregating hormone, in the portal circulation of cirrhotic patients. In the present study, we compared the platelet aggregation and coagulation and fibrinolytic profiles in portal circulation with those in systemic circulation in twenty cirrhotic patients complicated with hepatocellular carcinoma. A portal blood sample was collected through a fine needle inserted percutaneously and guided ultrasonographically to the intrahepatic portal vein. Simultaneously, venous blood was drawn from a forearm vein as the systemic blood sample. Coagulation and fibrinolytic profiles were assessed by examining the extrinsic fibrinolytic system (tissue plasminogen activator (tPA), t-PA-plasminogen activator inhibitor complex), fibrinogen degeneration product, fibrinogen euglobulin lysis time, platelet count, and platelet aggregation elicited by ADP and collagen. Although fibrinolytic factors were activated in patients in the present study, there were no significant differences between the portal and systemic blood samples in all the coagulation and fibrinolytic parameters examined except for platelet aggregation. The curve of platelet aggregation response to collagen (1, 2, 10 μg/ml), but not that to ADP, shifted significantly more to the right in the portal blood compared to the systemic blood (P<0.05). This result suggested that the difference in prostaglandin generation reported previously, may cause the dissociation between collagen and ADP elicitation of platelet response in portal blood while there is no effect on other parameters in the coagulation and fibrinolytic profiles.     

Plasminogen activators in the human endometrium, cellular origin and hormonal regulation.

Endometrial tissue explants in culture were found to release urokinase-type plasminogen activator (u-PA) and tissue-type plasminogen activator (t-PA). In order to identify their cellular origin and possible hormonal regulation, enriched cultures of glandular epithelial cells and stromal cells were prepared from fresh endometrium, and the cultures treated with hormones. Both epithelial and stromal cell cultures were found to secrete u-PA and t-PA. Treatment of epithelial cell cultures with oestradiol, progesterone and DH-testosterone had no effect on the secretion of t-PA or u-PA. In stromal cell cultures, on the other hand, the secretion of u-PA was significantly reduced after treatment with progesterone, whereas oestradiol and DH-testosterone had no effect. This reduction of u-PA antigen in the tissue culture medium did not result from a reduction of the relative level of u-PA mRNA in the cells, suggesting that the synthesis of u-PA was not reduced. Alternatively, an increased clearance of u-PA by the cells from the medium may explain the reduction. This in vitro observation probably reflects the in vivo reduction of u-PA in endometrial secretion during the secretory phase.     

Prevention of bleomycin-induced lung fibrosis by aerosolization of heparin or urokinase in rabbits

Bleomycin is a well known fibrogenic agent, provoking an initial adult respiratory distress syndrome-like injury with subsequent strong fibroproliferative response. Severe abnormalities of the alveolar surfactant system, which may be linked to the appearance of alveolar fibrin deposition, have been implicated in the pathogenetic sequence of events. Using a model of standardized aerosol delivery of 1.8 U bleomycin/kg body weight in rabbits, we investigated the influence of repetitive nebulization of heparin or urokinase-type plasminogen activator (u-PA) on the development of lung fibrosis. In an "early" (Days 2-12 postbleomycin) or "late" (Days 14-24 post-bleomycin) treatment protocol, approximately 3,500 U heparin or approximately 6,500 U u-PA was delivered to the bronchoalveolar space. Within four weeks, the bleomycin challenge provoked severe pulmonary fibrosis with reduction of lung compliance, marked increase in soluble collagen (bronchoalveolar lavage fluid) and hydroxyproline content (lung tissue), a typical reticular fibrosis pattern on high-resolution computed tomography, and typical histologic findings. Therapeutic intervention resulted in a far-reaching normalization of compliance, suppression of soluble collagen and hydroxyproline accumulation, and virtual abrogation of the computed tomography scan and histologic features of lung fibrosis, with most prominent effects seen in the early heparin and late u-PA administration. No bleeding complications occurred. These findings strongly support the concept that alveolar fibrin generation is an important event in the development of postbleomycin lung fibrosis. "Compartmentalized" anticoagulation and/or fibrinolysis via inhalational deposition of interventional agents in the alveolar compartment may thus offer a new therapeutic strategy for prevention of fibrosis.     

Prevention of metastasis by inhibition of the urokinase receptor.

The plasminogen activator urokinase (u-PA) mediates proteolysis by a variety of human tumor cells. Competitive displacement of u-PA from cellular binding sites results in decreased proteolysis in vitro, suggesting that the cell surface is the preferred site for u-PA-mediated protein degradation. We studied the effect of u-PA receptor blockade on the metastatic capacity of human PC3 prostate carcinoma cells, using transfectants which expressed chloramphenicol acetyl-transferase (CAT). Eight weeks after subcutaneous inoculation of these cells into nude mice, CAT activity was detected in regional lymph nodes, femurs, lungs, and brain, thereby mimicking the organ tropism observed for naturally occurring metastases of prostate cancer. In a second transfection, CAT-expressing PC3 cells received cDNA encoding a mutant u-PA (Ser356-->Ala) which lacks enzymatic activity but which retains full receptor binding affinity. Three mutant u-PA expressors, each with < 5% of wild-type cell-associated u-PA activity, were compared in vivo with independently derived controls. Primary tumor growth was similar in each group of animals and all tumors expressed comparable CAT activity. In contrast, metastasis (as assessed by CAT activity) was markedly inhibited when cell surface u-PA activity was blocked. Levels of CAT activity were reduced by a factor of > 300 in regional lymph nodes, 40-100 in brain tissue, and 10-20 in lung tissue. Metastatic capacity was inhibited similarly when animals were given intermittent intraperitoneal injections of a u-PA/IgG fusion protein capable of displacing u-PA activity from the tumor cell surface. Our results indicate that cell surface u-PA activity is essential to the metastatic process. In addition, the assay system employed in these experiments may be generally useful in testing other therapeutic modalities to limit the spread of primary tumors.     

Role of urokinase and its receptor in basal and stimulated colonic epithelial cell migration in vitro

BACKGROUND: Migration of colonic epithelial cells is important for mucosal repair following injury. The urokinase (u-PA) system regulates migration in other cell types. AIM: To examine the role of u-PA and its receptor (u-PAR) in colonic epithelial cell migration. METHODS: Migration was assessed over 24 hours in circular wounds made in confluent monolayers of LIM1215 and Caco-2 human colon cancer cells. The function of u-PA and u-PAR was ablated with antisense oligonucleotides to block expression, with synthetic u-PA peptides to block interaction, and with aprotinin to block u-PA mediated proteolysis. RESULTS: Migration was stimulated two to threefold by exogenous u-PA, an effect dependent on u-PAR binding but independent of u-PA mediated mitogenesis and proteolysis. Expression of u-PA and u-PAR was inhibited by 80% by the appropriate antisense oligonucleotide. Basal migration and the motogenic effects of butyrate, epidermal growth factor, and phorbol-12-myristate-13-acetate were suppressed by the u-PAR antisense oligonucleotide (40-60%) but were at best minimally affected following inhibition of u-PA expression and binding. CONCLUSIONS: In an in vitro model of wounded colonic epithelium, u-PAR promotes cell migration through mechanisms that are not exclusively dependent on u-PA binding. Therefore, u-PA and u-PAR may contribute to colonic mucosal repair in vivo.     

A prospective study on the prognostic significance of urokinase-type plasminogen activator levels in breast cancer tissue

Urokinase-type plasminogen activator (u-PA), which cleaves plasminogen to yield plasmin, is a serine protease of fibrinolysis and is presumed to play a key role in extracellular proteolysis and facilitate the migration of cancer cells. This study was conducted prospectively to evaluate the prognostic significance of u-PA antigen level in breast cancer tissues. u-PA concentrations in the cytosol of 226 breast cancer tissues were determined prospectively by enzyme-linked immunosorbent assay using cytosol fractions prepared for steroid hormone assay. The median follow-up period of the patients was 60 months. Various prognostic factors were evaluated by univariate analysis or multivariate analysis using the Cox proportional-hazards method. Patients with primary breast cancer containing high levels of u-PA had a significantly shorter disease-free survival than patients with low levels of u-PA antigens. In multivariate analysis, a high level of u-PA was an independent risk factor for disease-free survival, being independent of age, axillary node status, and estrogen receptor status. Among the major prognostic factors, a high u-PA antigen level, lymph node involvement, and a positive estrogen receptor status were the most important for predicting relapse-free survival (P=0.044, P<0.0001, P=0.0039). This first prospective study confirmed the prognostic significance of the u-PA antigen level in association with other major prognostic factors. The results of our present study suggest that u-PA in breast cancer tissue might be involved in breast cancer invasion and metastasis. Received: 20 November 1996 / Accepted: 9 June 1997     

Bone matrix degradation by the plasminogen activation system. Possible mechanism of bone destruction in arthritis

The observed increase in urokinase-type plasminogen activator (u-PA) and its receptor (u-PAR) in synovial tissue of patients with rheumatoid arthritis (RA) suggests pathophysiological involvement of the plasminogen activation (PA) system in inflammatory joint disease. In the present study, we investigated the capacity of the PA system to degrade non-mineralized and mineralized bone-like matrix in vitro as a model for bone destruction. Transfected mouse LB6 cell lines, that expressed either human u-PA or u-PAR, were cultured separately and simultaneously on radiolabelled bone matrix in the presence of plasminogen. Osteoblast-like murine calvarial MC3T3-E1 cells were used to produce a well-characterized, highly organized bone-like matrix, that could be mineralized in the presence of beta-glycerol phosphate. Bone matrix degradation was followed by the release of radioactivity in the culture medium. u-PA-producing cells, in contrast to u-PAR- producing cells, degraded both non-mineralized and mineralized bone matrix. This effect could be inhibited by anti-u-PA antibodies, as well as by tranexamic acid and by aprotinin, indicating that the degrading activity is u-PA mediated and plasmin dependent. Co-cultivation of a small portion of u-PA-producing cells with u-PAR-expressing cells resulted in a marked increase in degradation activity. Reduction of this potentiating effect by suramin or the amino-terminal fragment of u- PA, both competitive inhibitors of u-PA receptor binding, shows that this synergistic effect is due to binding of u-PA to u-PAR. u-PAR must be cell associated, as binding of u-PA to a soluble u-PAR prevented this enhancement. The capability of the PA system to degrade bone matrix in vitro, and the previously demonstrated increased expression of u-PA and u-PAR in synovial tissue of patients with RA, further support a role for the PA system in the development of bone erosions.      

Biochemical properties potentially rendering human brain microvasculature vulnerable to proteolytic injury associated with the use of fibrinolytic drugs

BACKGROUND: Determinants of predisposition to intracranial bleeding in response to the administration of thrombolytic drugs have not yet been well characterized. OBJECTIVE: To delineate factors involved, by characterizing susceptibility of human cerebral microvascular endothelium (HCME) to injury associated with inflammatory cytokines, levels of which are typically elevated in blood in patients who have suffered a myocardial infarction or stroke and been treated with thrombolytic drugs. METHODS: Elaboration of fibrinolytic system proteins by HCME exposed either to interleukin-1 beta or to tumor necrosis factor-alpha (TNF) in serum-free medium for 24 h was characterized. Cell-conditioned medium was assayed for tissue-type plasminogen activator (t-PA), urokinase-type plasminogen activator (u-PA), and plasminogen activator inhibitor type 1--(PAI-1) by enzyme-linked immunosorbent assay. To determine whether the induction of u-PA was mediated by oxygen-centered radicals, the following were added to media: superoxide dismutase (a scavenger of O2-.), catalase (a scavenger of O2-. and H2O2) and dimethylthiourea (a scavenger of OH.). RESULTS: Interleukin-1 beta had no effect upon elaboration of fibrinolytic system proteins by HCME. By contrast, TNF selectively increased elaboration of u-PA. Accumulation of t-PA and PAI-1 remained unchanged. Accumulation of u-PA was inhibited by cycloheximide, implying that there was a requirement for protein synthesis. Dimethylthiourea abolished the increase elaboration of u-PA induced by TNF completely, catalase did so partially, and SOD did not do so at all. CONCLUSION: The propensity of HCME to elaborate u-PA rather than PAI-1 appears to render cerebral microvasculature particularly vulnerable to proteolytic attack in settings in which inflammatory cytokines are elaborated locally or in which their concentrations in blood are elevated.     

High plasma urokinase-type plasminogen activator levels are present in patients with acute nonlymphoblastic leukemia.

An exaggerated hemorrhagic syndrome is a characteristic in acute non-lymphoblastic leukemia (ANLL) and it determines the patient's outcome. Disseminated intravascular coagulation as a result of a procoagulant factor release and primary hyperfibrinolysis due to plasminogen activators also released by leukemic cells have been implicated in the development of this syndrome. The aim of this work was to evaluate urokinase-type plasminogen activator (u-PA) and related parameters of the fibrinolytic system in 14 ANLL patients. Our results showed an increased u-PA concentration in ANLL patients compared to controls [2.63 (1.61-4.62) vs. 0.95 (0.77-1.48) ng/ml, p < 0.01]. u-PA levels correlated positively with tissue-type plasminogen activator. The relevance of the enhancement of u-PA in this clinical setting was supported by the fact that it was the only analytical parameter positively correlated with patient mortality (p < 0.05). Though u-PA levels do not seem to be the determining factor in the development of the hemorrhagic syndrome of ANLL patients, a contributory role of this plasminogen activator is suggested from our results.     

恶性肿瘤止凝血分子标志物转录的临床研究

目的　检测胃肠道恶性肿瘤止凝血分子标志物血浆含量及mRNA水平 ,探讨其与肿瘤浸润、播散的关系及检测的临床意义。方法　采用逆转录实时定量PCR技术检测 2 9例胃癌、2 3例肠癌患者组织中组织因子 (TF)、组织型纤溶酶原激活剂 (t PA)、尿激酶型纤溶酶原激活剂 (u PA)mRNA水平 ;用ELISA法同步检测患者血浆止凝血分子标志物含量 ,包括TF、凝血酶抗凝血酶复合物 (TAT)、t PA、u PA、u PA受体 (u PAR)、纤溶酶 抗纤溶酶复合物 (PAP)等。结果　术前恶性肿瘤组血浆TF、TAT、u PA、u PAR、PAP含量均较正常对照明显升高 (P <0 0 5 ) ,其中 ,有局部浸润、淋巴结肿大、远处脏器转移者u PA、u PAR升高更为显著 (P <0 0 1) ;TF、u PAmRNA在肿瘤细胞表达显著增高 (P <0 0 1) ,而t PAmRNA(P >0 0 5 )则减少。结论　凝血、纤溶功能亢进是胃肠道恶性肿瘤细胞易播散、浸润的主要原因之一。t PAmRNA的表达可能为组织分化较好的特征。逆转录实时定量PCR技术 ,使TF、u PAmRNA有望作为胃肠道恶性肿瘤病情监测指标而用于临床     

p38MAPK信号转导通路在EGF诱导食管腺癌SEG-1细胞表达u-PA中的作用

目的:探讨表皮生长因子(epidermal growth factor,EGF)对人食管腺癌SEG-1细胞尿激酶型纤溶酶原激活物(urokinase-type plasminogen activator,u-PA)mRNA和蛋白表达的影响及p38MAPK信号转导通路在其中的作用.方法:以相同浓度的EGF(100g/L)按时间梯度刺激SEG-1细胞,应用Western blot法测定各时间点总p38MAPK蛋白、磷酸化p38MAPK蛋白、u-PA蛋白表达,并应用RT-PCR方法检测各时间点u-PAmRNA表达.用p38MAPK特异抑制剂SB203580预处理细胞后,观察上述指标变化.结果:EGF可明显增强SEG-1细胞(u-PA)mRNA和蛋白的表达,并可激活p38MAPK蛋白的磷酸化,具有时间依赖性.SB203580能明显抑制EGF诱导的p38MAPK蛋白的磷酸化,用其阻断p38MAPK信号转导通路后,EGF对u-PAmRNA和蛋白表达的诱导作用受到显著抑制,并且具有剂量依赖性.结论:EGF可通过p38MAPK信号转导通路诱导SEG-1细胞表达u-PA.     

Evaluation of esophageal varices in liver disease by splenic-pulp manometry,splenoportography, and esophagogastroscopy

Summary and Conclusion Esophagogastroscopy, splenic-pulp manometry, and splenoportography were combined in a prospective study of 60 patients with documented liver disease and suspected portal hypertension. All three procedures were performed on each of the patients within a 6-day period. Twenty patients were actively bleeding at the time of endoscopic examination.Esophagogastroscopy demonstrated varices in 90% of the patients studied. Splenoportography, however, demonstrated collateral circulation in only 50% of the patients with endoscopically demonstrated varices. In no instance did splenoportography demonstrate collateral circulation not previously seen on endoscopy. Splenoportography failed to demonstrate collateral circulation in all patients whose splenic-pulp pressure was less than 270 mm. water.In 20 patients with upper gastrointestinal bleeding, the height of the splenic-pulp pressure was a poor index of the site of bleeding. Eight patients with portal hypertension and esophageal varices were found to be bleeding from nonvariceal sites. Conversely, 5 patients with active bleeding from endoscopically demonstrated varices had no collateral circulation revealed by splenoportography.It is evident from this study that splenic-pulp manometry, splenoportography, and esophagogastroscopy will frequently yield divergent results in the evaluation of portal hypertension and portosystemic collateral circulation in patients with liver disease. While splenoportography may be useful in determining the patency of the portal vein and demonstrating large spontaneous or surgical portosystemic shunts, esophagogastroscopy is a better method for detecting esophageal varices and determining whether they are bleeding. The height of the splenic-pulp pressure is of little value in indicating the site of upper gastrointestinal bleeding.Supported in part by Graduate Training Grant TI-AM-5237 and Clinical Research Center Grant AM-05576-02 from the National Institute of Arthritis and Metabolic Diseases, N.I.H., U. S. Public Health Service, and Contract U 1373 of the Health Research Council of the City of New York.