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Antonio Delgado

Publications and source records attributed to Antonio Delgado.

At least 19 recordsLinked to original sources
PubMed2007

Drug-eluting stents for the treatment of bifurcation lesions: a randomized comparison between paclitaxel and sirolimus stents.

BACKGROUND: Drug-eluting stents have been shown to reduce restenosis in many types of lesions. The purpose of this article is to assess the efficacy of sirolimus- and paclitaxel-eluting stents in patients with bifurcation lesions. METHODS: Between June 2003 and October 2004, 205 patients were enrolled in a prospective randomized trial; 103 patients were assigned to sirolimus stents and 102 patients to paclitaxel stents. All patients were treated by provisional T-stenting. RESULTS: There were no differences between groups in terms of age, risk factors, clinical condition, location of the bifurcation lesion, or other technical factors. Angiographic data and immediate results were also similar in both groups. Three patients developed inhospital non-Q-wave acute myocardial infarction (2 from the sirolimus group and 1 from the paclitaxel group). Follow-up angiography was obtained in 109 patients (53%). In the sirolimus group, 5 patients developed restenosis (9%): 1 at the main vessel, 2 at the side branch, and 2 in both branches. In contrast, 16 patients from the paclitaxel group had restenosis (29%): 6 at the main vessel, 5 at the side branch, and 5 in both branches. Target lesion revascularization at 24 +/- 5 months post stenting occurred in 4 patients from the sirolimus group (4%) and in 13 from the paclitaxel group (13%) (P < .05). Late loss at the main vessel in the sirolimus group patients was 0.31 +/- 0.59 versus 0.60 +/- 0.77 mm in patients from the paclitaxel group (P < .05). CONCLUSIONS: Patients with bifurcation lesions treated by sirolimus showed significantly lower rates of late loss, restenosis and target lesion revascularization than patients treated with paclitaxel-eluting stents.

Aged↗
PubMed2006

Solid-phase synthesis of a combinatorial library of dihydroceramide analogues and its activity in human alveolar epithelial cells.

Solid-phase synthesis of a small combinatorial library of dihydroceramide analogues as mixtures of erythro and threo diastereomers is described. Some dihydroceramide analogues cause growth arrest and apoptosis in a dose-dependent manner in human alveolar epithelial cells. This activity is likely due to the threo isomers, as evidenced by cellular studies with a pair of diastereomerically pure N-acyldihydrosphingosines. The apoptotic activity reported in this work provides information for the design of new compounds that may provide the basis for the generation of biochemical tools for the study of different pathologies where ceramide and/or dihydroceramide are involved.

Apoptosis↗
PubMed2006

Inhibitors of sphingolipid metabolism enzymes.

Sphingolipids are a family of lipids that play essential roles both as structural cell membrane components and in cell signalling. The cellular contents of the various sphingolipid species are controlled by enzymes involved in their metabolic pathways. In this context, the discovery of small chemical entities able to modify these enzyme activities in a potent and selective way should offer new pharmacological tools and therapeutic agents.

Amidohydrolases↗
PubMed2006

Design, synthesis and activity as acid ceramidase inhibitors of 2-oxooctanoyl and N-oleoylethanolamine analogues.

The synthesis of novel N-acylethanolamines and their use as inhibitors of the aCDase is reported here. The compounds are either 2-oxooctanamides or oleamides of sphingosine analogs featuring a 3-hydroxy-4,5-hexadecenyl tail replaced by ether or thioether moieties. It appears that, within the 2-oxooctanamide family, the C3-OH group of the sphingosine molecule is required for inhibition both in vitro and in cultured cells. Furthermore, although the (E)-4 double bond is not essential for inhibitory activity, the (E) configuration is required, since the analogue with a (Z)-4 unsaturation was not inhibitory. None of the oleamides inhibited the aCDase in vitro. Conversely, with the exception of N-oleoylethanolamine and its analogs with S-decyl and S-hexadecyl substituents, all the synthesized oleamides inhibited the aCDase in cultured cells, although with a relatively low potency. We conclude that novel aCDase inhibitors can evolve from N-acylation of sphingoid bases with electron deficient-acyl groups. In contrast, chemical modification of the N-oleoylsphingosine backbone does not seem to offer an appropriate strategy to obtain aCDase inhibitors.

Animals↗
PubMed2006

Analysis of the flow field induced by the sessile peritrichous ciliate Opercularia asymmetrica.

The feeding mechanism of the sessile protozoon Opercularia asymmetrica (Oligohymenophorea, Peritrichia) relies on the cilia beat generating a flow field that convectively transports suspended particles and dissolved substances to the oral cavity of the organism. By use of optical micro-flow measurement and theoretical methods the flow environment of two neighbouring peritrichous ciliate cells is studied. Both, yeast cells (Saccharomyces cerevisiae) and artificial flow tracers are used for the visualisation of the flow field. Artificial tracers are rejected by the protozoa and deviate from the fluid path lines, while yeast cells follow the flow almost perfectly. This is shown through a dimensional analysis of the involved hydrodynamic forces on the tracers. The measured flow field exhibits maximum velocities of 25 microm/s at around 20 microm distance ahead of an individual ciliate. The flow field extends 200 microm from the location of the ciliate. A nicking motion of the protozoon is observed and found not to obey any periodic law. Multiples of protozoa exhibit most commonly an alternating cilia beat regime generating a non-stationary flow field. It can be shown through theoretical methods that fluid exchange is enhanced in this alternating regime compared to a flow field generated by a single ciliate. Fluid exchange depends on the distance of the ciliates from each other and on the alteration frequency of the cilia beat. The comparison of an analytical Stokes' flow solution with the observed fluid flow serves to determine the force required to maintain the flow field against viscous dissipation. The force magnitude is in the order of magnitude of 10-100 pN.

Animals↗
PubMed2006

A randomized, double-blind trial assessing the efficacy and safety of sublingual metopimazine and ondansetron in the prophylaxis of chemotherapy-induced delayed emesis.

The prevention of delayed emesis following chemotherapy remains an important challenge. This randomized, double-blind, double-dummy, multicenter study was designed to compare the efficacy and tolerance of metopimazine and ondansetron at preventing nausea and emesis in patients receiving chemotherapy. Two hundred patients were evaluated for efficacy: 103 patients received metopimazine (7.5 mg x 2 t.i.d.) and 97 received ondansetron (8 mg b.i.d.) for 5 days. Patients were asked to report episodes of nausea and emesis in a diary, and quality of life (QoL) was evaluated using the Functional Living Index--Emesis questionnaire. The incidence of complete response (defined as no nausea and emesis for 5 days) did not differ between the two treatment arms (53.4% for metopimazine versus 49.5% for ondansetron; P=0.58). No significant difference was found for the incidence of emesis (23.3% for metopimazine versus 30.9% for ondansetron) or QoL. Tolerance was as expected for both drugs and comparable, except for the incidence of gastrointestinal disorders, which was significantly lower in the metopimazine group (19.4 versus 32.7%; P=0.03). We conclude that metopimazine is an alternative to ondansetron that is better tolerated for the prevention of delayed emesis in patients receiving chemotherapy.

Administration, Sublingual↗
PubMed2005

Regio- and stereoselective synthesis of aminoinositols and 1,2-diaminoinositols from conduritol B epoxide.

[Chemical reaction: See text] A systematic approach to the regio- and stereoselective synthesis of aminoinositols and 1,2-diaminoinositols arising from tetra-O-benzylconduritol B epoxide (9) and its aziridine analogue 22, respectively, is described. In all cases, the synthetic methodologies rely on the regio- and stereocontrolled azidolysis of the starting precursors to give the corresponding trans regioadducts. Subsequent functional group manipulation under strict configurational control affords the isomeric cis adducts. Chemoselective functionalization of the diamine moiety in 1,2-diaminoinositol derivatives can be achieved by the proper design of the reaction sequence and choice of reagents. The described protocols allow efficient access to each of the eight possible configurations of the 1,2-diamino and 1,2-amino alcohol moieties from chemical modifications of the epoxide moiety on the common precursor 9.

Amines↗
PubMed2005

On the regio- and stereoselective synthesis of aminocyclitols from cyclitol epoxides: the effect of Li as a chelating agent.

Experimental and theoretical studies on the influence of Li ions on the regio- and the stereoselectivity of the reaction of cyclitol epoxides with nitrogen nucleophiles have been carried out. Model studies with NaN3 as a nucleophile in the absence of Li ions predict a mixture of C1 and C2 regioadducts. The inclusion of two Li ions as a chelating agent favours the operation of a low populated "all-axial" conformation leading ultimately to the C1 adducts. In all cases, the results can be rationalised by geometric and energetic considerations of the corresponding transition states. Predictions of the theoretical calculations are in good agreement with the experimental results using primary and secondary amines as nucleophiles, and thus confirm the validity of this study.

Chelating Agents↗
PubMed2005

New aminocyclitols as modulators of glucosylceramide metabolism.

A series of 13 aminocyclitol derivatives belonging to two different families is described. Their configuration is governed by the regio- and stereocontrolled epoxide opening of a suitably protected conduritol-B epoxide. Studies on several glycosyl processing enzymes indicate that some of them are good inhibitors of glucosylceramide hydrolase. A rationale to account for preliminary structure-activity relationships is provided.

Enzyme Inhibitors↗
PubMed2005

Aldol additions of dihydroxyacetone phosphate to N-Cbz-amino aldehydes catalyzed by L-fuculose-1-phosphate aldolase in emulsion systems: inversion of stereoselectivity as a function of the acceptor aldehyde.

The potential of L-fuculose-1-phosphate aldolase (FucA) as a catalyst for the asymmetric aldol addition of dihydroxyacetone phosphate (DHAP) to N-protected amino aldehydes has been investigated. First, the reaction was studied in both emulsion systems and conventional dimethylformamide (DMF)/H2O (1:4 v/v) mixtures. At 100 mM DHAP, compared with the reactions in the DMF/H2O (1:4) mixture, the use of emulsion systems led to two- to three-fold improvements in the conversions of the FucA-catalyzed reactions. The N-protected aminopolyols thus obtained were converted to iminocyclitols by reductive amination with Pd/C. This reaction was highly diastereoselective with the exception of the reaction of the aldol adduct formed from (S)-N-Cbz-alaninal, which gave a 55:45 mixture of both epimers. From the stereochemical analysis of the resulting iminocyclitols, it was concluded that the stereoselectivity of the FucA-catalyzed reaction depended upon the structure of the N-Cbz-amino aldehyde acceptor. Whereas the enzymatic aldol reaction with both enantiomers of N-Cbz-alaninal exclusively gave the expected 3R,4R configuration, the stereochemistry at the C-4 position of the major aldol adducts produced in the reactions with N-Cbz-glycinal and N-Cbz-3-aminopropanal was inverted to the 3R,4S configuration. The study of the FucA-catalyzed addition of DHAP to phenylacetaldehyde and benzyloxyacetaldehyde revealed that the 4R product was kinetically favored, but rapidly disappeared in favor of the 4S diastereoisomer. Computational models were generated for the situations before and after C-C bond formation in the active site of FucA. Moreover, the lowest-energy conformations of each pair of the resulting epimeric adducts were determined. The data show that the products with a 3R,4S configuration were thermodynamically more stable and, therefore, the major products formed, in agreement with the experimental results.

Aldehyde-Lyases↗
PubMed2005

Evidence for in situ crude oil biodegradation after the Prestige oil spill.

In November 2002, the oil tanker Prestige sank off the Spanish coast after releasing approximately 17,000 tones of heavy fuel, coating several hundred kilometers of coastline in oil sludge. In December 2002 and February 2003, samples were collected from the shore of the Galician coast to analyse the indigenous population ability to carry out crude oil degradation in situ. Carbon isotopic ratio of the dissolved inorganic carbon (DIC) in seawater samples was used as a rapid method to directly assess activity of microbes on the oil components. 12CO2/13CO2 ratio in samples from certain locations along the coast revealed degradation of a very delta13C-negative source such as the Prestige crude oil (-30.6 per thousand). Putative biodegradation processes taking place at areas with high income of fresh seawater could not be detected with this technique. Laboratory-scale biostimulation processes carried out in samples with the highest oil biodegradation activity showed that N/P deficiency in seawater is a limiting factor for crude oil degradation. The most probable number (MPN) of crude oil component degraders was estimated for several aromatic compounds (naphthalene, anthracene, phenanthrene, pyrene) and for undecane. Our results clearly show that bacteria present in the contaminated water are readily able to transform components of the crude oil into inorganic carbon.

Bacteria↗
PubMed2005

Sirolimus-eluting stents for treatment of in-stent restenosis: immediate and late results.

We analyzed the clinical, angiographic, and late intravascular ultrasonographic findings from 140 patients whose in-stent restenosis was treated with sirolimus-eluting stents. In-stent restenosis remains the main limitation to percutaneous coronary revascularization and has a high recurrence rate after bare stent implantation. From May 2002 through July 2003, we studied 140 patients with clinical restenosis after bare-stent treatment. In 107 patients, in-stent restenosis occurred de novo; in 28 patients, this was the 2nd restenosis; and in another 5, it was the 3rd occurrence. A sirolimus-eluting stent was implanted directly after angiographic evaluation of the in-stent restenosis in 79 patients and after pre-dilation in 61 patients. All patients were given the following antithrombotic regimen: low-molecular-weight heparin, ticlopidine, and aspirin for 1 month, followed by clopidogrel and aspirin for 1 year. Primary success was achieved in 137 patients. Three patients had a non-Q wave myocardial infarction. At the 1-month evaluation, 2 patients had died: 1 due to subacute stent thrombosis and another due to acute mesenteric ischemia. After a mean follow-up of 16 +/- 4 months, the major adverse cardiac events were acute myocardial infarction due to late stent thrombosis in 2 patients and the need for target lesion revascularization in 15 patients. Late angiographic evaluation was performed in 97 patients (69%), 16 of whom had new restenosis: 14 of the restenoses were intrastent, and 2 were at the edges of the stent. Our results suggest that sirolimus-eluting stents are effective in the prevention of in-stent restenosis and, therefore, may become the leading treatment alternative for patients with in-stent restenosis.

Aged↗
PubMed2005

[Six-month intravascular ultrasound follow-up of coronary bifurcation lesions treated with rapamycin-eluting stents: technical considerations].

INTRODUCTION AND OBJECTIVES: In vitro studies show that stents deform when dilated laterally to access a side branch. This phenomenon may be avoided by use of a kissing balloon at the end of the procedure. However, to date, no in vivo data are available. Our objectives were to investigate the main vessel stent using intravascular ultrasound (IVUS) at six-month follow-up in 55 patients with bifurcation lesions treated using rapamycin-eluting stents and to examine the effect of technical factors. PATIENTS AND METHOD: All patients were treated using provisional or T stents. At 6 months, IVUS measurements were made in the main vessel at both proximal and distal ends of the stent, in reference segments, immediately below the side branch ostium, and at the points where the lumen was smallest and where stent expansion was greatest. RESULTS: The lumen area immediately below the side branch ostium was significantly smaller than that at the point of maximum stent expansion (6.7 [1.8] vs 5.1 [1.3] mm2; P<.05). Underexpansion was not influenced by use of a kissing balloon (stent area immediately under the side branch ostium: 5.5 [0.9] vs 5.6 [1.6] mm2; P=NS) and only one patient experienced restenosis at this point. The lumen areas at the proximal and distal edges of the stent were almost identical in patients who did or did not undergo balloon dilation beyond the ends of the stent. CONCLUSIONS: Stent underexpansion below the side branch ostium was frequently found following provisional or T stenting of bifurcation lesions. This minor stent deformity was not prevented by use of a kissing balloon nor by any specific side branch treatment and had no significant impact on the restenosis rate.

Combined Modality Therapy↗
PubMed2004

Rapamycin-eluting stents for the treatment of unprotected left main coronary disease.

BACKGROUND: Conventional bare stents have been used to treat unprotected left main (LM) coronary artery stenosis. However, restenosis remains the main limitation. Since rapamycin-eluting stents (RES) appear to inhibit neointimal proliferation, their application to this specific site seems promising. METHODS: Since May 2002, we have studied a series of 52 patients with LM lesions treated with RES. Forty-seven patients presented with de novo stenoses, and 5 had in-stent restenosis; 19 patients required combined stent treatment for other remote lesions in the coronary tree, 6 of them at the level of proximal right coronary artery. The RES was implanted directly at the LM in 39 patients; 13 others needed predilation. Once deployed, the RES was overexpanded with short balloons adjusted to the LM length in 44 patients. Quantitative coronary angiograms were analyzed in the same view before and immediately after treatment and at follow-up. Patients were followed-up closely and new cardiac catheterization was scheduled at 6-month evaluation or earlier in the presence of symptoms. At follow-up study, quantitative coronary angiography and motorized intravascular ultrasound analyses were performed in 35 (67%) patients. RESULTS: Primary success was obtained in 50 patients (96%). Two patients (4%) developed a non-Q-wave myocardial infarction. All patients were symptom-free at discharge. After a mean follow-up of 12 +/- 4 months, 50 patients (96%) remain asymptomatic. No late death or acute thrombosis have been recorded. Two patients became symptomatic 2 and 4 months after treatment, respectively. One had restenosis at a remote site, while the other had in-segment restenosis. None of the remaining 33 angiographically evaluated patients developed restenosis at any site. Target lesion revascularization was 1/52 (2%). CONCLUSIONS: Although longer-term follow-up studies are needed, the tailored treatment of coronary lesions located at the LM by overexpanded RES is feasible and safe. Midterm results seem promising, which might help to shift the orientation of patient management from surgical to percutaneous revascularization.

Angioplasty, Balloon, Coronary↗
PubMed2004

Rapamycin-eluting stents for the treatment of bifurcated coronary lesions: a randomized comparison of a simple versus complex strategy.

BACKGROUND: Rapamycin-eluting stents (RES) have been shown to reduce restenosis in many types of lesions. However, the ideal strategy for the treatment of coronary bifurcated lesions has not been established to date. This randomized study compares 2 strategies for the RES treatment of bifurcation lesions: a simple approach (stenting the main vessel and balloon dilatation for the side branch [SB]) versus a complex approach (stents for both vessels). METHODS: To compare both strategies, a randomized study was conducted in 91 patients with true coronary bifurcation lesions. All patients received an RES at the main vessel, covering the SB. Patients from group A (n = 47) were assigned to balloon dilation of the involved SB (simple strategy); patients in group B (n = 44) were randomized to receive a second stent at the SB origin (complex strategy). There were no differences between groups regarding baseline clinical and angiographic data. RESULTS: Major adverse cardiac events occurred in 3 patients from group A (2 non-Q-wave myocardial infarctions and 1 target lesion revascularization). Six-month angiographic reevaluation was obtained in 80 patients (88%). Restenosis of the main vessel was observed in 1 (2%) patient from group A and in 4 (10%) from group B. Restenosis of the SB appeared in 2 (5%) patients from group A and in 6 (15%) from group B. CONCLUSIONS: Both strategies are effective in reducing the restenosis rate, with no differences in terms of clinical outcome. Elective SB stenting seems to provide no advantages over the simpler stent jail followed by SB balloon dilation.

Angioplasty, Balloon, Coronary↗
PubMed2004

Numerical simulation of the mechanics of a yeast cell under high hydrostatic pressure.

The mechanical effects of the compression of a yeast cell (Saccharomyces cerevisiae) under high hydrostatic pressure used for the processing of food and food ingredients are modelled and simulated with the finite-element method. The cell model consists of a cell wall, cytoplasm a lipid filled vacuole and the nucleus. Material parameters have been taken from literature or have been derived from thermodynamic relationships of water and lipids under high hydrostatic pressure. The model has been validated for a pressure load up to 250 MPa. Comparison of the volume reduction to in situ experimental observations reveals very good agreement. Dimensional analysis of the governing equations shows that transient pressure application in a high-pressure food process does not enhance structural inactivation (mechanical damage), unless pressure oscillation frequencies of 700 MHz are applied. The deformation of the cell under pressure deviates strongly from isotropic volume reduction. Especially, organelle membranes exhibit large effective strain values. Hydrostatic stress conditions are preserved in the interior part of the cell. A pressure load of 400 MPa, which is critical upon disruption of cell organelle membranes, generates an effective strain up to 80%. In the cell wall, the stress state is heterogeneous. Von-Mises stress reaches the critical value upon failure of the cell wall of 70+/-4 MPa at a pressure load between 415 and 460 MPa.

Biomechanical Phenomena↗
PubMed2004

Fatty acid biosynthesis is involved in solvent tolerance in Pseudomonas putida DOT-T1E.

The unusual tolerance of Pseudomonas putida DOT-T1E to toluene is based on the extrusion of this solvent by constitutive and inducible efflux pumps and rigidification of its membranes via phospholipid alterations. Pseudomonas putida DOT-T1E-109 is a solvent-sensitive mutant. Mutant cells were less efficient in solvent extrusion than the wild-type cells, as shown by the limited efflux of 14C-1,2,4-trichlorobenzene from the cell membranes, despite the fact that the efflux pumps are overexpressed as a result of increased expression of the ttgDEF and ttgGHI efflux pump operons. This limitation could be the result of alterations in the outer membrane because the mutant cells released more beta-lactamase to the external medium than the wild-type cells. The mutant P. putida DOT-T1E-109 showed negligible synthesis of fatty acids in the presence of sublethal concentrations of toluene as revealed by analysis of 13CH3-13COOH incorporation into fatty acids. In contrast, the mutant strain in the absence of solvents, and the wild-type strain, both in the presence and in the absence of toluene, incorporated 13CH3-13COOH at a high rate into de novo synthesized lipids. The mutation in P. putida DOT-T1E-109 increases sensitivity to the solvent because of a limited efflux of the solvent from the cell membranes with the concomitant inhibition of fatty acid biosynthesis.

Fatty Acids↗