No abstract is provided for this article.
Clinical trials have demonstrated the efficacy of glycoprotein (GP) IIb/IIIa antagonists in preventing the thrombotic end points of death, myocardial infarction, and urgent revascularization when they are administered at the time of percutaneous coronary revascularization (PTCR). It has been postulated that prolongation of receptor blockade beyond acute intervention would extend the clinical benefit of these agents. The Evaluation of Oral Xemilofiban in Controlling Thrombotic Events (EXCITE) study was a multicenter, international, randomized placebo‐controlled trial of the oral GP IIb/IIIa antagonist Xemilofiban administered prior to and after PTCR. The study was designed to assess the efficacy and safety of continuing oral xemilofiban for 6 months to prevent these primary thrombotic end points. More than 7,200 patients were randomized in 29 countries to receive placebo or one of two doses of xemilofiban. Stenting was performed at the discretion of the operator. All patients received aspirin and periprocedural heparin; all stented patients received continuous xemilofiban, or ticlopidine for 2–4 weeks followed by xemilofiban‐placebo. Most patients were also evaluated 1 month after conclusion of the study drug treatment. Clinical data from up to 6 months of drug treatment and 1 month posttreatment were used to evaluate the acute and long‐term efficacy and safety of xemilofiban. Secondary end points included the need for any revascularization, repeat hospitalization for unstable angina, and nonhemorrhagic stroke. The cumulative incidence of bleeding events and effects of xemilofiban in stented and nonstented patients were evaluated. The efficacy of continuing xemilofiban and aspirin therapy as the sole antithrombotic medications following stent deployment was assessed against a ticlopidine and aspirin control group. The incremental clinical benefit of long‐term receptor blockade over acute receptor antagonism was evaluated.
No abstract is provided for this article.
Conference Abstract| January 01 1989 Platelet Activating Factor (PAF) Stimulates Phosphoinositide (PI) Metabolism in Guinea Pig Eosinophils C. Kroegel; C. Kroegel 1Department of Thoracic Medicine, National Heart and Lung Institute, London SW3 6LY Search for other works by this author on: This Site PubMed Google Scholar E.R. Chilvers; E.R. Chilvers 1Department of Thoracic Medicine, National Heart and Lung Institute, London SW3 6LY Search for other works by this author on: This Site PubMed Google Scholar P.J. Barnes P.J. Barnes 1Department of Thoracic Medicine, National Heart and Lung Institute, London SW3 6LY Search for other works by this author on: This Site PubMed Google Scholar Clin Sci (Lond) (1989) 76 (s20): 45P. https://doi.org/10.1042/cs076045P Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter LinkedIn Cite Icon Cite Get Permissions Citation C. Kroegel, E.R. Chilvers, P.J. Barnes; Platelet Activating Factor (PAF) Stimulates Phosphoinositide (PI) Metabolism in Guinea Pig Eosinophils. Clin Sci (Lond) 1 January 1989; 76 (s20): 45P. doi: https://doi.org/10.1042/cs076045P Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu nav search search input Search input auto suggest search filter All ContentAll JournalsClinical Science Search Advanced Search This content is only available as a PDF. Article PDF first page preview Close Modal You do not currently have access to this content.
Objectives We sought to investigate the clinical benefit of additional stent implantation after achieving an optimal result of balloon angioplasty (BA) in long coronary lesions (>20 mm). Background Long coronary lesions are associated with increased early complications and late restenosis after BA. Stenting improves the early outcome, but stent restenosis is also related to both lesion length and stent length. Methods A total of 437 patients with a single native lesion 20 to 50 mm in length were included and underwent BA, using long balloons matched to lesion length and vessel diameter (balloon/artery ratio 1.1) to achieve a diameter stenosis (DS) <30% by on-line quantitative coronary angiography (QCA). “Bail-out stenting” was performed for flow-limiting dissections or >50% DS. Patients in whom an optimal BA result was achieved were randomized to additional stenting (using NIR stents) or no stenting. The primary end point was freedom from major adverse cardiac events (MACE) at nine months, and core laboratory QCA was performed on serial angiograms. Results Bailout stenting was necessary in 149 patients (34%) and was associated with a significantly increased risk of peri-procedural infarction (p < 0.02). Among the 288 randomized patients, the mean lesion length was 27 ± 9 mm, and the vessel diameter was 2.78 ± 0.52 mm. The procedural success rate was 90% for the 143 patients assigned to BA alone (control group), as compared with 93% in the 145 patients assigned to additional stenting (stent group), which resulted in a superior early minimal lumen diameter (0.54 mm, p < 0.001) and led to reduced angiographic restenosis (27% vs. 42%, p = 0.022). Freedom from MACE at nine months was 77% in both groups. Conclusions A strategy of provisional stenting for long coronary lesions led to bailout stenting in one-third of patients, with a threefold increase in peri-procedural infarction. Additional stenting yielded a lower angiographic restenosis rate, but no reduction in MACE at nine months.
The energy absorption and structural isolation performance of axially-compressed sandwich structures constructed with stiff face plates separated with an auxetic lattice core metamaterial is studied. Advances in additive manufacturing increasingly allow bespoke, carefully designed, structures to be included within the core lattice to enhance mechanical performance. Currently, the internal structure of the lattice core is deliberately disrupted geometrically to engineer suitable post-buckling behaviour under quasi-static loading. The desirable properties of a high fundamental stiffness and a practically zero underlying stiffness in the post-buckling range ensure that energy may be absorbed within a limited displacement and that any transfer of strain to an attached structure is minimized as far as is feasible. It is demonstrated that such disruptions can be arranged to enhance the panel performance. The concept may be extended to promote cellular buckling where the internal lattice buckles with densification occurring at defined locations and in sequence to absorb energy while maintaining a low underlying mechanical stiffness.
Background The risk of rupture and subsequent thrombosis of the atherosclerotic coronary plaques is related to the presence of necrotic core with high lipid content. We conducted an exploratory pilot trial to compare the capability for lipid tissue detection using four intra-coronary diagnostic techniques: greyscale intravascular ultrasound (GS IVUS), IVUS radiofrequency data (IVUS RFD) analysis, optical coherence tomography (OCT) and intravascular magnetic resonance spectroscopy (IVMR). Methods Twenty-four matched target plaques were analyzed with the 4 techniques in non-culprit lesions in five patients with stable angina. Following IVUS pullback, OCT and IVMR was performed. Plaque composition was assessed using established criteria of each technology. Results Atherosclerotic plaques classified as soft by GS IVUS were mainly composed by fibro-fatty (80%) or necrotic core (20%) by IVUS RFD. These soft plaques were classified as “lipid-rich” by OCT in the majority of cases (80%). IVMR confirmed the presence of lipid with a lipid fraction index ranging between 36 and 79 in these soft plaques. Besides this good agreement for soft plaques, GS IVUS, IVUS RFD and OCT had 100% agreement in the identification of calcified plaques. Conclusion The present study explored multi-modality imaging of atherosclerotic plaque in-vivo. Assessing specifically lipid-rich plaques, there was generally good agreement for plaque components identified as soft by traditional GS IVUS with RFD and OCT whereas IVMR showed a varying amount of lipid in these regions. Nevertheless there continues to remain inherent variation, namely as a result of the different imaging resolutions and the lack of common nomenclature and classification.
In order to examine the role of nitric oxide (NO) on airway mucus secretion we studied the effects of the nitric oxide synthase (NOS) inhibitor l ‐N G ‐monomethyl‐ l ‐arginine ( l ‐NMMA), a novel nitric oxide donor, (±)‐( E )‐ethyl‐2‐[( E )‐hydroxyimino]‐5‐nitro‐3‐hexeneamide (FK409), and the NO precursor l ‐arginine on basal mucus secretion in the ferret trachea in vitro in Ussing chambers. We also determined the effects of these agents upon secretion induced by electrical stimulation of nerves or by acetylcholine (ACh). We used 35 SO 4 as a mucus marker. l ‐NMMA (0.01‐1 mM) increased basal output of 35 SO 4 ‐labelled macromolecules with a maximal increase above baseline of 248% at 0.1 mM l ‐NMMA. l ‐Arginine (1 mM) alone had no significant effect on basal secretion but reversed the potentiating effect of l ‐NMMA on basal secretion. l ‐NMMA‐induced increases in basal mucus secretion were sustained for at least 30 min in the continuing presence of the NOS inhibitor. In contrast to the potentiating effects of l ‐NMMA, FK409 (100 nM) reduced basal secretion by 60% (at 1 nM and at 10 nM it was without effect). Electrical stimulation (50 V, 10 Hz, 0.5 ms for 5 min) increased 35 SO 4 output by 174%. l ‐NMMA (1 and 10 mM) present during stimulation of tracheal segments resulted in significant potentiations of 214% and 116%, respectively, of the neurogenic response. The potentiated response to 10 mM l ‐NMMA was reversed by l ‐arginine (1 mM). At this dose l ‐arginine had no effect itself on basal secretion. In contrast to the potentiating effects of l ‐NMMA on neurogenic secretion, FK409 at 10 nM and 100 nM inhibited the neurogenic response by 98% and 99%. At all concentrations tested, neither l ‐NMMA (0.01 mM − 1 mM) nor FK409 (1 − 100 mM) had any significant effect on ACh‐induced mucus secretion. These observations lead us to conclude that nitric oxide, derived from constitutive NO synthase, acts as an endogenous inhibitor of both basal and neurogenic mucus secretion in ferret trachea in vitro .
To answer the question of whether thrombolysis is a clinically useful approach in acute myocardial infarction, we initiated in May 1981 a randomized trial to compare a strategy aimed at early recanalization by intracoronary administration of streptokinase with conventional treatment in the coronary care unit. The primary objective was to study the effect of the intervention on mortality and morbidity after myocardial infarction. In addition, we analyzed the effect of attempted thrombolysis on infarct size and left ventricular function measured by various methods. The intake was completed in March 1985 after entry of 533 patients. The data presented in this report demonstrate that improved survival after early thrombolysis in acute myocardial infarction is indeed associated with a reduction of infarct size and with preservation of global left ventricular function. Furthermore, regional wall motion after thrombolysis appeared to be better than in the control group. The difference between the present study and the other randomized trials published thus far can be explained by differences in study design, by the shorter delay between the onset of symptoms and treatment, and by its larger size.
Current design specifications for steel and composite structures generally assume elastic-plastic or rigid-plastic material behaviour, which means that the beneficial influence of strain hardening is neglected. This assumption may lead to overly conservative strength predictions particularly for stocky bare steel sections and composite beams subjected to sagging bending. The continuous strength method (CSM) is a deformation based design approach that allows for strain hardening in the design of metallic cross-sections. Although the method has been successfully applied to bare steel, stainless steel and aluminium alloy cross-sections, use of the CSM for steel-concrete composite structural components, which may considerably benefit from strain hardening, has not been extensively studied. Thus, the primary purpose of this study is to extend the application of the CSM to composite structures, with an emphasis on simply supported beams subjected to sagging bending.
