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E Bastida

Publications and source records attributed to E Bastida.

At least 19 recordsLinked to original sources
PubMed1992

The role of subendothelial laminin and platelet laminin receptors in haemostasis.

Laminin (LM) is a basement membrane glyco-protein which exhibits a number of biological activities, including the promotion of cell attachment and migration. In a static system, platelets attach to LM without spreading. In order to elucidate the mechanisms mediating platelet-LM interactions under flow conditions, we studied the effects of blocking subendothelial LM and its platelet receptor. We measured the extent of platelet adhesion to the endothelial cell extracellular matrix (ECM) using a parallel plate perfusion chamber. To do this, we performed the following experiments: i) blockade of subendothelial LM by incubation of ECM with an anti-LM antibody (Ab); ii) blockade of the platelet receptor for LM with: a) an anti-67 KDa receptor Ab; and b) three different LM-derived peptides (CFALRGDNP, IKVAV and CDPGYIGSR). In i) perfusates consisted of whole blood, whereas in ii) perfusates were prepared with washed platelets pre-incubated with Ab or peptides and reconstituted with plasma and washed red blood cells. Perfusions were carried out at 800 s-1 shear rate. Platelet deposition was morphometrically evaluated by a computerized system. Our results indicated that when ECM was pre-incubated with an anti-LM Ab (100 micrograms/ml, 30 min, 37 degrees C) a reduction of the surface coverage (SC) of 23.3 +/- 2.3% (p less than 0.01) was observed. When washed platelets were pre-incubated with an anti-67 KDa receptor Ab (40 micrograms/ml, 30 min, 37 degrees C) their interaction with ECM was decreased by 22.3 +/- 2.1% of SC (p less than 0.005). In other experiments platelets were pre-incubated with CFALRGDNP, IKVAV and CDPGYIGSR (200 micrograms/ml, 30 min, 37 degrees C).(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1992

[The effect of low-dose acetylsalicylic acid on platelet aggregation parameters in vitro].

In order to elucidate whether a single dose of 150 mg acetylsalicylic acid three times a day, provokes significant changes into platelet aggregation, we analyzed a group of 50 patients who underwent coronary revascularization. During 48 hours before surgery, all patients received 100 mg dipyridamole orally every 6 hours and 1 hour after the end of the operation 100 mg dipyridamole via nasogastric tube. Patients were then randomized into three groups to receive 3 times a day a capsule containing: 50 mg acetylsalicylic acid, 50 mg acetylsalicylic acid plus 75 mg dipyridamole or placebo. Before the antiplatelet therapy was started, the day of the operation and 5 days after the onset of the treatment, blood samples were taken to determine platelet aggregation (turbidimetric technique) and the thromboxane A2 liberation. The three groups were comparable for all the studied clinical and angiographic variables. Preoperative dipyridamole did not provoke significant changes in platelet aggregation (acetylsalicylic acid group 86.5 +/- 10% vs 71 +/- 28.8%; acetylsalicylic acid + dipyridamole group 81.5 +/- 7.8% vs 75.3 +/- 22.7%; placebo group 83.7 +/- 8.9% vs 70 +/- 21.5%). After 5 days of treatment with acetylsalicylic acid, both groups under active treatment showed a significant (p less than 0.001) decrease of aggregability (acetylsalicylic acid 12.8 +/- 4.4%; acetylsalicylic acid + dipyridamole 20.5 +/- 17%; placebo 72 +/- 21.5%).(ABSTRACT TRUNCATED AT 250 WORDS)

Aspirin↗
PubMed1991

Dipyridamole induces changes in the thrombogenic properties of extracellular matrix generated by endothelial cells in culture.

Dipyridamole (DIP) is a drug widely used as an antiplatelet agent, which also has effects on endothelial cells. In this study, the effects of treating confluent endothelial cell monolayers (EC) with DIP on EC viability (trypan blue exclusion test) and metabolic activity (3H-thymidine incorporation) were examined. Platelet reactivity of the extracellular matrix (ECM) produced by untreated and DIP-treated ECs was determined morphometrically by a perfusion technique. Levels of ECM-associated von Willebrand factor (vWF) and fibronectin (FN) were also quantified (ELISA). The present results indicate that treatment of EC with 10 microM DIP did not reduce EC viability but that the incorporation of labelled nucleotides was significantly decreased (p less than 0.01). Platelet deposition onto the ECM generated by DIP-treated cells, perfused at a shear rate of 1300 sec-1, differed significantly with respect to controls (p less than 0.05), and platelet adhesion was also reduced (25% less, p less than 0.05). This effect was shear rate dependent, as no differences were noted when the ECMs were perfused at 300 sec-1 shear rate. Levels of VWF and FN associated with ECM remained unchanged with respect to controls. These results suggest that treatment with DIP alters EC metabolic activity, which in turn, influences the reactivity of the ECM generated by treated cells.

Cell Count↗
PubMed1991

Comparison between human umbilical artery and rabbit abdominal aorta as substrata for platelet adhesion and platelet thrombus formation under flow conditions.

Rabbit abdominal aortas and human umbilical arteries are currently used as substrata for the study of platelet adhesion and aggregate formation under flow conditions. Using immunohistochemical and ultrastructural methods, we have analyzed both vessel surfaces. The reactivity towards platelets of the subendothelium (SE) exposed on these vessels after mechanical or enzymatic digestion (alpha-chymotrypsin) was morphometrically quantified and the nature of the interaction studied in the electron microscope. After mechanical damage, the ultrastructural study of rabbit aortas showed a clearly defined internal elastic lamina (IEL). In contrast, umbilical vessels lacked a consistent IEL and masses of amorphous material often located deeper in the media were the main constitutents of the SE. Immunohistochemical labeling of the von Willebrand factor bound to both types of vessel differed considerably. Quantification of platelet interactions after perfusion of citrated blood showed qualitative differences between mechanically damaged rabbit or human vessels. Enzymatic digestion produced a more thrombogenic surface on rabbit aortas (p less than 0.01 vs. nondigested), but decreased their reactivity towards platelets on umbilical arteries (p less than 0.01 vs. nondigested). The ultrastructural study of the interacting platelets revealed that aggregates, when present, were found on the extracellular matrix underlying endothelial cells of rabbit aortas, but interacting with fibrillar structures probably derived from cell elements of the media in the case of umbilical arteries. These findings indicate that rabbit aortas and umbilical arteries possess structural characteristics that result in different thrombogenic properties with respect to circulating platelets.

Aorta, Abdominal↗
PubMed1991

Effects of endothelial cell treatment on 13-HODE and prostacyclin synthesis and its correlation with tumor cell-vascular endothelial cell adhesion.

Adhesion of tumor cells to vascular endothelial surfaces is one of the key steps in metastatic dissemination. Several factors are believed to be implicated in the regulation of the adhesive properties of tumor cells. We show that the adhesion of five different tumor cell lines, all of them of human origin, to human umbilical vascular endothelial cells (ECs) significantly increases following pretreatment of ECs with the cytokines interleukin-1 and tumor necrosis factor, whereas tumor cell/EC interactions remained unchanged after incubation with interferon-gamma. Significant augmentation in tumor cell adhesion was also observed when ECs were treated with the lipoxygenase inhibitors salicylate and the compound BW755C. In all cases, increased tumor cell adhesion was concomitant with significant decreases in the EC levels of linoleic acid, lipoxygenase-derived metabolite 13-hydroxy-octadecadienoic acid (13-HODE). On the contrary, pretreatment of the EC monolayers with aspirin did not result in any changes towards tumor cell adhesion. These results suggest that tumor cell/EC interaction is modulated, at least in part, by intracellular levels of 13-HODE and is independent of prostacyclin (PGI2) production by the ECs.

6-Ketoprostaglandin F1 alpha↗
PubMed1991

[The midterm (6 years) clinical results of the Carpenter-Edwards supra-annular bioprosthesis].

We present here the clinical results with a second-generation porcine bioprosthesis, the Carpentier-Edwards supra-annular valve (CESA). Two-hundred and twenty-two CESA bioprostheses were implanted in 189 patients during a four-year period (from 1984 to 1987), either as an isolated procedure or associated to mitral or tricuspid repair. The mid-term clinical results have been evaluated after a mean follow-up of 3.4 years, being 96% complete. There were 16 in-hospital deaths (8.4%) and 6 late, potentially valve-related, cardiac deaths (1.1% patients/year). Overall, 86.7 +/- 2% of the patients were free from cardiac death at 6 years (95.1 +/- 2% of the patients surviving the operative period). Linearized rates of valve related complications were the following: 1.4% patients/year for thromboembolism (including valve thrombosis), 0.5% patients/year for treatment-related hemorrhage and 0.7% patients/year for endocarditis. We did not found any case of either intrinsic or extrinsic valve failure, unrelated to infection of thrombosis. Two patients were reoperated, one because of valve thrombosis and the other due to prosthetic valve endocarditis (reoperation rate of 0.3% patients/year). When lethal and nonlethal valve-related complications (including in-hospital deaths) were considered all together, 75.8 +/- 8.4% of the patients remained alive and free of morbid events at 6 years. When patients were grouped according to the valve replaced (aortic, mitral and multiple), best results were found with patients submitted to isolated aortic valve replacement. We conclude that the CESA bioprosthesis has an excellent mid-term clinical performance. However, longer follow-up is necessary to know if improvement in valve design and manufacturing results in increased valve durability.

Aortic Valve↗
PubMed1991

Evaluation of synthetic novel ether aminophosphoglycerides for glucocorticoid-receptor complex modulator activity.

Modulator is an endogenous low-mol wt regulator of the glucocorticoid-receptor complex. Structural analysis of purified modulator suggested that it was a novel ether aminophosphoglyceride (Bodine and Litwack 1988b). Analogs of the putative modulator structure have now been synthesized. The synthetic compounds are 1-O-(6-carboxylhexyl)-glycero-3-phosphoserine and the sn-2-methoxy and sn-1-ethylester derivatives. Like modulator, these novel synthetic compounds are water soluble. However, thin-layer chromatography and spectroscopic analysis of these phosphoglycerides indicated significant structural differences between modulator and the synthetic analogs. In particular, the chromatographic behavior of the compounds suggests that modulator is more highly charged than the synthetic derivatives. The synthetic compounds, as well as lysophosphatidylserine, were also tested for in vitro modulator activity using the glucocorticoid-receptor complex activation inhibition and steroid-binding stabilization assays. None of the analogs exhibited modulator activity in these assays. However, the synthetic compounds were generally less detrimental to receptor steroid-binding than lysophosphatidylserine. From this work, we conclude that although modulator is not mimicked by one of these synthetic phosphoglycerides, a starting point for future structure-function studies has nonetheless been established.

Amines↗
PubMed1990

Uremic platelets have a functional defect affecting the interaction of von Willebrand factor with glycoprotein IIb-IIIa.

Uremic patients have an impaired platelet function that has been related to membrane glycoprotein (GP) abnormalities. Using a perfusion system, we have studied the interaction of normal and uremic platelets with vessel subendothelium (SE) under flow conditions. Reconstituted blood containing washed platelets, purified von Willebrand factor (vWF) (1 U/mL), and normal washed red blood cells was exposed to de-endothelialized rabbit segments for 10 minutes at two different shear rates (800 and 1,600 seconds-1). In some experiments a monoclonal antibody to the GPIIb-IIIa complex (EDU3) was added to the perfusates. With normal platelets, the percentage of the vessel covered by platelets (%CS) was 23.1% +/- 3.7% at 800 seconds-1 and 30% +/- 4.3% at 1,600 seconds-1. Platelets were observed in contact or forming monolayers on vessel SE. EDU3 inhibited the spreading of normal platelets. The %CS (11.1% +/- 3.3%) was statistically decreased (P less than .01) and most of the platelets were observed in contact with the vessel surface. These data indicate that, under flow conditions, the interaction of vWF with GPIIb-IIIa can support the spreading of normal platelets in the absence of exogenous fibrinogen. Under the same experimental conditions, the interaction of uremic platelets with SE was markedly impaired at both shear rates studied (P less than .01 v normal platelets). The presence of EDU3 did not modify the interaction of uremic platelets. These results confirm the impairment of the platelet adhesion observed in uremic patients. Furthermore, they indicate the presence of a functional defect in the interaction of vWF with GPIIb-IIIa. The fact that perfusions with normal and uremic platelets in the presence of an antibody to the GPIIb-IIIa complex did not show any differences gives indirect evidence on a functionally normal interaction vWF/GPIb in uremic patients.

Blood Platelets↗
PubMed1990

Cyclic AMP regulation of endothelial cell triacylglycerol turnover, 13-hydroxyoctadecadienoic acid (13-HODE) synthesis and endothelial cell thrombogenicity.

The 15-omega-lipoxygenase enzyme in endothelial cells metabolizes endogenous linoleic acid (18:2) into 13-hydroxyoctadecadienoic acid (13-HODE) under basal conditions, i.e., in unstimulated endothelial cells. 13-HODE is thought to regulate the non-adhesivity of the endothelium, contributing to vessel wall/blood cell biocompatibility. We performed experiments, therefore, to determine the relationship between basal levels of cAMP, 13-HODE synthesis, and platelet/endothelial cell adhesion. We found that 13-HODE synthesis increased with elevated cAMP levels and that the elevated 13-HODE levels correlated with increased 18:2 turnover in the triacylglycerol pool. In contrast, neither 18:2 nor arachidonic acid (20:4) turnover in the phospholipid nor prostacyclin (PGI2) production were changed with elevated cAMP levels. Platelet/endothelial cell adhesion was inversely proportional to 13-HODE synthesis. We conclude that intracellular 13-HODE influences platelet/vessel wall interactions, is synthesized from 18:2 released from the endogenous triacylglycerol pool, and that this pathway is modulated by intracellular cAMP levels.

Arachidonic Acid↗
PubMed1990

Differential localization of von Willebrand factor, fibronectin and 13-HODE in human endothelial cell cultures.

Von Willebrand factor (vWF), fibronectin (FN) and 13-hydroxy-octadecadienoic acid (13-HODE) are known to influence the regulation of the adhesive properties of vascular surfaces. In the present study vWF, FN and 13-HODE were comparatively localized in endothelial cells (EC) and in the extracellular matrix (ECM) produced by EC. An indirect immunofluorescent technique was applied to coverslips containing human EC cultures previously fixed and permeabilized following different procedures: A. Alcohol/acetone; B. Paraformaldehyde alone and C. Paraformaldehyde followed by Triton X-100. vWF was observed inside EC (A), on the ECM produced by EC (B) or in EC and ECM (C) depending on the fixation procedures used. FN was mainly localized in the ECM despite the fixation procedures employed. FN was only seen in relation to cell bodies after strong permeabilization (A). Under our experimental conditions 13-HODE was never found in ECM. This latter antigen was observed randomly dispersed in those preparations fixed with alcohol/acetone, indicating that it is probably extracted by this fixative. 13-HODE was detected in granular shaped structures in EC after permeabilization with detergent (C). These results suggest that the cellular localization of vWF and FN is compatible with an adhesive role related to the abluminal side of ECs. 13-HODE was readily observed after mild permeabilization. This finding would be morphologically consistent with its contribution to the regulation of the vessel wall thromboresistance.

Cells, Cultured↗
PubMed1990

Flow capacity of the human retrograde internal mammary artery: surgical considerations.

The diastolic flow of the retrograde internal mammary artery (IMA) was calculated in 30 patients and compared with the expected coronary flow of the left ventricle and that of specific branches. Arterial pressure and free flow were measured in the proximal and distal IMA as well as in the superior epigastric and musculophrenic arteries. Systolic and mean arterial pressure were significantly higher in the proximal IMA than in any other site, but diastolic pressure was comparable. Overall and diastolic antegrade IMA flows (77 +/- 6 and 44 +/- 3 mL/min) were significantly greater than the retrograde flows through the distal IMA (18.5 +/- 2 and 11.5 +/- 1 mL/min), musculophrenic artery (13.3 +/- 1 and 7.9 +/- 1 mL/min), and superior epigastric artery (5.3 +/- 0.4 and 3.1 +/- 0.2 mL/min). Only patient-size-related variables correlated significantly with retrograde IMA flow. Diastolic retrograde IMA flow represented 8.5% +/- 0.6% of the expected left ventricle coronary flow and in 12 patients (40%) was greater than the expected flow of at least one posteroinferior coronary artery. Based on these data, the retrograde IMA may adequately perfuse the posterior descending or other posterolateral coronary branches in select patients. Previous measuring of the retrograde flow is mandatory.

Adult↗
PubMed1990

Selective and adjustable pericardial flap to protect internal mammary artery grafts.

We describe the surgical technique of a localized and adjustable pericardial flap to protect internal mammary artery grafts. This flap allows selective pulmonary retraction, maintains pleural integrity, and saves most of the pericardium for later closure. This technique has proved to be simple and highly effective. We have used it in 80 patients and have not had any related complications.

Humans↗
PubMed1990

[Update on the role of vascular, plasmatic and cellular components in the regulation of the interaction of platelets with the subendothelium].

The interaction of platelets (Plts) with subendothelium (SE) or with extracellular matrices (ECM) generated by endothelial cells was studied under flow conditions. The role of: a) platelet membrane glycoproteins (GPS) or subunits; b) plasma adhesive proteins such as von Willebrand factor (VWF) and fibronectin (Fn); and c) structural proteins of the SE such as laminin (Lm). Specific antibodies or purified proteins were added to the perfusates. GPS. Monoclonal antibodies (MoAb) directed against distinct epitopes of the GPIIb-IIIa affected in different manner the deposition of platelets. MoAb EDU3 decreased (p less than 0.01) the surface of the vessel covered by platelets (% CS) and increased the presence of platelets in contact (% C) with the SE. MoAb C17 did not modify the % CS but altered the morphological characteristics of the aggregates. A monoclonal antibody against GPIIb, decreased the % CS (p less than 0.01) without influencing % C; VWF. A linear progression of the % CS was observed for VWF levels ranging from 0.1 to 0.6 U/mL. A plateau was reached for concentrations of vWF above 0.6 U/mL; Fn. Perfusions in which blood was reconstituted with Fn-depleted plasma showed the cooperation of this protein facilitating Plt-Plt interaction. No statistical differences were observed in the % CS when ECM were incubated with a MoAb against Fn (3E3); Lm. The % CS decreased statistically (p less than 0.01) when SE or ECM were incubated with an antibody to Lm. These results show the critical role of vascular, plasmatic and cellular components in the maintenance of and adequate platelet function.

Animals↗
PubMed1990

[Long-term experience with multivalve replacement with the Medtronic-Hall mechanical prosthesis].

During the period from January to September 1986, 182 Medtronic-Hall (M-H) heart valve prostheses were implanted in 89 patients, mainly because of rheumatic valve disease (68.5%). The patients were divided in two groups. Group I consisted of 83 patients with aortic and mitral valve replacement. Six patients with tricuspid valve replacement plus aortic and/or mitral valve replacement constituted group II. In group I the majority of the patients (86.7%) were in functional class III or IV (NYHA). Twenty three patients had undergone at least one previous cardiac operation. Hospital mortality was 6.02% (5/83). In group II the patients were in functional class III or IV (NYHA). Hospital mortality was 33.3% (2/6). Death occurred in the operating room in only one instance. Follow-up was completed in 98.9% and extended from 27 months to 8 years (348.7 patient years in group I and 23.08 patient years in group II). The overall 5 and 8 years actuarial survival, freedom of thromboembolism and freedom from endocarditis rates in group I were: 80.8 +/- 4.4% and 72.7 +/- 5.2%; 89.8 +/- 4% and 85.8 +/- 4.7%; 94.8 +/- 1.2 and 93.1 +/- 1.7%. In group II, actuarial studies were not carried out because of the scanty number of cases. There were another complications in group I: haemorrhage due to anticoagulation in 6 cases, hemolysis in 8 instances and periprosthetic leaks in 2 cases. There were no cases of structural failure. We conclude that after 8 years of follow-up the M-H valve prosthesis shows an excellent clinical performance and mechanical reliability, and the incidence of valve-related complications was in the low range of that reported with other mechanical prostheses.

Adult↗
PubMed1990

The role of platelets in cancer metastasis.

Clinical, experimental and ultrastructural studies strongly suggest a role for platelets in metastatic dissemination. Several mechanisms have been proposed to explain the potential contribution of blood platelets to the metastatic cascade. Experimentally, many tumour cells of either animal or human origin have the capacity to activate platelets, although the mechanisms by which malignant cells exert this effect is not yet fully understood. Possible mechanisms include: (1) generation of thrombin; (2) activation by ADP; (3) release of cathepsin B; (4) eicosanoid metabolism. A number of observations also indicated that tumour-cell-induced platelet aggregation required specific receptor sites. We have shown that platelet glycoprotein GPIb and the complex GPIIb/IIIa are necessary for tumour-cell-induced platelet aggregation. We and others reported the isolation of a microparticulate aggregating material from different types of tumour cell lines. This material has been identified as a sialolipoprotein complex which possesses tissue-factor-like activity. The role of sialic acid in the metastatic potential of cells is also believed to be important and may partly modulate their interactions with platelets. In vivo, rheological factors may also regulate the interactions of tumour cells with blood and vascular structures and an alternative approach to the evaluation of platelet-tumour-cell interaction under dynamic conditions has been the use of perfusion systems. Thus, we have established the crucial role of Ca2+ in supporting tumour-cell-platelet activation and subsequent thrombus formation. More recently we investigated the patterns of adhesion of a highly metastatic human adenocarcinoma of the lung to exposed extracellular matrix generated by human vascular endothelial cells in culture.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Diphosphate↗
PubMed1990

A rapid embedding procedure for the study of platelet interactions with extracellular matrices in a flowing system. Effect of aspirin on platelet activity.

The cultured endothelial cell (EC) is currently used as a model for the study of the interaction of platelets with the vascular wall. Described is a method for rapid quantitative and qualitative evaluation of platelet interactions with extracellular matrices (ECM) produced by human cultured ECs growing on plastic coverslips. Morphometric calculations can be performed on the same perfused coverslips. A very good correlation (r = 0.96) was found between results of a morphometric method en face and those obtained from analysis of cross sections of the perfused coverslips. A shear rate-dependent increase on platelet deposition onto ECMs was observed with both morphometric procedures. The method is sensitive enough to detect drug-related changes of platelet function. An impairment of the interaction of platelets with the ECM was observed when blood obtained from healthy volunteers who took 500 mg aspirin/day for five days was perfused. Aspirin showed a marked effect, decreasing platelet spreading onto the subendothelium (p less than 0.05). The embedding method described benefits from the use of plastic coverslips that are easily detected from the glycol methacrylate compound used for the embedding procedure. Quantitative analysis en face (covered surface) and qualitative evaluation of platelet interactions (contact, adhesive and aggregated platelets) in cross sections are performed on the same coverslip. This embedding procedure provides a useful tool for the study not only of platelet interactions with ECMs but also for the investigation of interactions of blood elements with other cultured cells.

Aspirin↗
PubMed1990

[Variations in the thrombogenic properties of the extracellular matrix produced by endothelial cells in consecutive passages].

Cultured endothelial cells are currently used as a model for the study of the interaction of platelets with the vascular wall under flow conditions. Little is known about the influence of cell-culture conditions on the preservation of the original characteristics of primary tissues. In our study, the reactivity of platelets towards extracellular matrices produced by endothelial cells from different passage numbers was morphometrically evaluated. The presence and distribution of the extracellular von Willebrand factor was analyzed by immunofluorescent techniques. Morphology of endothelial cells in culture varied dramatically along the culture and polymorphism increased clearly at fourth or fifth passages. Extracellular matrix thrombogenicity decreased significantly from the fifth passage number. Simultaneously, von Willebrand factor distribution in ECM changed its typical pattern. Our results confirm that the extracellular matrix produced by human umbilical vein derived-endothelial cells constitutes a good model for the study of platelet adhesion onto vascular subendothelium. The limited viability of ECs and the variation in the thrombogenic properties of ECM formed after multiple passages must be taken into account when these cells or their products are used in experimental research.

Cell Division↗