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Biomedical subjects

Eduardo Moreno

Publications and source records attributed to Eduardo Moreno.

13 recordsLinked to original sources
PubMed2007

Three-dimensional versus two-dimensional transesophageal echocardiography in mitral valve repair.

OBJECTIVES: We sought to compare the diagnostic performance of 3-dimensional (3D) versus 2-dimensional (2D) echocardiography in patients with regurgitant mitral valve. BACKGROUND: An accurate assessment of morphology and function of the mitral valve is essential for surgical repair. Two-dimensional echocardiography has certain spatial limitations that could be overcome by 3D imaging. METHODS: Preoperative transesophageal 2D and 3D studies were compared with surgical findings in patients undergoing surgical repair for severe mitral regurgitation. RESULTS: A total of 81 consecutive patients underwent surgical repair (2002-2004). There was a high concordance (88%-100%) between both 2D and 3D studies and surgical findings in classification of involved segments. 3D imaging more accurately classified A1 segment defects (P = .05) and commissural dysfunction (P = .02). The 2D study incorrectly classified 22 segments, mainly corresponding to complex disease. The 3D study incorrectly classified 14 segments, unrelated to complex disease. Good agreement (94%, kappa 0.845) was found between non-expert and expert interpretations of 3D images. CONCLUSIONS: Three-dimensional echocardiography offers high accuracy in mitral valve evaluation. It may complement 2D study in patients with complex valve anatomy, where surgical decisions are more difficult. The images can be easily interpreted by professionals without a high degree of experience.

Adolescent↗
PubMed2006

Synthesis of orthogonally protected biaryl amino acid derivatives.

The efficient and direct synthesis of protected biaryl amino acids, including dityrosine (50% overall yield over 3 steps), by Negishi cross-coupling of the serine-derived organozinc reagent 4 with iodo- and di-iodobiaryls, is reported. An improved, although still not perfect, diiodination of 2,2'-biphenol has been achieved using NMe3BnICl2-ZnCl2. Protection of phenolic hydroxyl groups as acetates, rather than benzyl ethers, is required for efficient cross-coupling, and evidence for acetyl migration has been observed during debenzylation of a substituted 2-acetoxy-2'-benzyloxybiaryl. Aromatic C-I to C-Cl conversion has been detected as a minor reaction pathway in the palladium-catalyzed coupling of aryl iodide 3b with organozinc reagent 4.

Amino Acids↗
PubMed2005

The competitive nature of cells.

The possibility that cells of multicellular organisms may compete with one another has been postulated several times. It was experimentally confirmed in Drosophila, probably for the first time, when cells with different metabolic rates were mixed: cells that would have been viable on their own disappeared due to the presence of metabolically more active cells. After almost 30 years of neglect, genetic analysis in Drosophila has started to reveal a gene network that regulates the competitive behavior of cells. If the genes regulating cellular competitiveness in Drosophila have a conserved function in mammals, the study of cell competition could have an impact in several biomedical fields, including functional degeneration, cancer, or stem cell therapies.

Animals↗
PubMed2005

The biocide triclosan selects Stenotrophomonas maltophilia mutants that overproduce the SmeDEF multidrug efflux pump.

The possibility that triclosan selects Stenotrophomonas maltophilia mutants overexpressing the multidrug resistance pump SmeDEF is analyzed. Five out of 12 triclosan-selected mutants were less susceptible to antibiotics than the wild-type strain and overproduced SmeDEF. Results are discussed in relation to current debates on the potential selection of antibiotic-resistant bacteria by household biocides.

Anti-Infective Agents, Local↗
PubMed2004

The brinker gradient controls wing growth in Drosophila.

The Decapentaplegic (Dpp) morphogen gradient controls growth and patterning in the Drosophila appendages. There is recent evidence indicating that the Dpp gradient is converted into an inverse gradient of activity of the gene brinker (brk), which encodes a transcriptional repressor and is negatively regulated by the Dpp pathway. We have studied how alterations in the Brk gradient affect the growth of the wing disc. We find that there is a negative correlation between brk activity and growth of the disc: high levels of brk prevent or reduce growth, whereas loss of brk activity results in excessive growth. This effect is concentration dependent: different amounts of Brk produce distinct rates of growth. Furthermore, our results demonstrate that although brk is able to induce apoptosis where there is a sharp difference in Brk levels, its role as a growth repressor is not achieved by inducing apoptosis but by reducing cell proliferation. Brk appears to downregulate the activity of genes that control cell proliferation, such as bantam.

Animals↗
PubMed2004

dMyc transforms cells into super-competitors.

Overexpression of myc protooncogenes has been implicated in the genesis of many human tumors. Myc proteins seem to regulate diverse biological processes, but their role in tumorigenesis remains enigmatic. Here we use Drosophila imaginal discs to mimic situations in which cells with unequal levels of Myc protein are apposed and show that this invariably elicits a win/lose situation reminiscent of cell competition; cells with lower levels of dMyc are eliminated by apoptosis whereas cells with higher levels of dMyc over-proliferate. We find that this competitive behavior correlates with, and can be corrected by, the activation of the BMP/Dpp survival signaling pathway. Hence the heritable increase in dMyc levels causes cells to behave as "super-competitors" and reveals a novel mode of clonal expansion that causes, but also relies on, the killing of surrounding cells.

Animals↗
PubMed2003

KLM model for lossy piezoelectric transducers.

A KLM model has been developed using equivalent circuits to analyze the effects of different loss mechanisms on the transducer performance in the time and frequency domain. Transducers from two different piezoelectric materials (lead-zirconate-titanate (PZT) and polyvinylidene fluoride) were constructed to validate our model. Experimental results are in good agreement with the theoretical simulation.

Transducers↗
PubMed2003

[Does the EuroSCORE identify patients at minimum risk of mortality from heart surgery?].

INTRODUCTION AND OBJECTIVES: Risk of hospital death is one of the key factors considered by the clinical cardiologist when weighting indications for surgery. Risk estimation scales establish distinct levels of risk in quantitative terms. The aim of the present study was to investigate whether a low EuroSCORE value corresponds to low mortality in our setting. PATIENTS AND METHODS: During 1999-2000 we prospectively calculated the EuroSCORE for all patients who underwent isolated coronary (CS) or valvular (VS) surgery. We then analyzed intrahospital mortality of patients with a low EuroSCORE. The validation group consisted of patients who underwent surgery in 2001 and obtained a low EuroSCORE. RESULTS: During 1999-2000 we identified 116 patients (16.2% of all patients treated with isolated CS or CV) with a low EuroSCORE (50 8.6 years; 65% male). Fifty-seven of these patients underwent isolated CS, and 59 of them isolated VS. Intrahospital mortality was zero. In 2001 we identified 59 (16.1%) such patients (49 8.7 years; 68% male), of whom 35 underwent isolated CS and 24 underwent isolated VS. Intrahospital mortality during this period was again zero. CONCLUSIONS: A low EuroSCORE identifies a population of patients with minimum risk of mortality after isolated coronary or valve surgery. The score may be useful as a sentinel indicator in analyses of the complex issue of quality of cardiac surgery.

Cardiac Surgical Procedures↗
PubMed2003

Performance analysis of ultrasono-therapy transducer with contact detection.

The performance of ultrasono-therapy transducer with contact detection by using the impedance phase change is described. Usually a therapy transducer is designed with a lambda/2 frontal plate glued to a PZT-4 piezoceramic. This plate ensures a good mechanical protection of the piezoceramic with a corresponding high-transmission energy. Normally this transducer is operated at the minimum at the frequency of the impedance module of its input electric impedance, but this operation point is affected by the shift caused by the expected temperature increase. This shift could be higher than the narrow bandwidth presented. As a result we obtain a decrease in the power level for medical treatment. Usually it is designed electronic drivers with automatic control that follow the frequency change, but the relatively narrow bandwidth introduces difficulty in the design. Another frequency operation point is presented here and analyzed using the criteria of the maximum of the impedance phase with a wider bandwidth than in the previous case. Simulation with mechanical losses are presented with experimental results that show the convenience of this criteria for practical application.

Equipment Failure Analysis↗
PubMed2002

Evolution of TNF signaling mechanisms: JNK-dependent apoptosis triggered by Eiger, the Drosophila homolog of the TNF superfamily.

Much of what we know about apoptosis in human cells stems from pioneering genetic studies in the nematode C. elegans. However, one important way in which the regulation of mammalian cell death appears to differ from that of its nematode counterpart is in the employment of TNF and TNF receptor superfamilies. No members of these families are present in C. elegans, yet TNF factors play prominent roles in mammalian development and disease. Here, we describe the cloning and characterization of Eiger, a unique TNF homolog in Drosophila. Like a subset of mammalian TNF proteins, Eiger is a potent inducer of apoptosis. Unlike its mammalian counterparts, however, the apoptotic effect of Eiger does not require the activity of the caspase-8 homolog DREDD, but it completely depends on its ability to activate the JNK pathway. Eiger-induced cell death requires the caspase-9 homolog DRONC and the Apaf-1 homolog DARK. Our results suggest that primordial members of the TNF superfamily can induce cell death indirectly by triggering JNK signaling, which, in turn, causes activation of the apoptosome. A direct mode of action via the apical FADD/caspase-8 pathway may have been coopted by some TNF signaling systems only at subsequent stages of evolution.

Amino Acid Sequence↗
PubMed2002

Cells compete for decapentaplegic survival factor to prevent apoptosis in Drosophila wing development.

During the growth of Drosophila imaginal discs a process called 'cell competition' eliminates slow-proliferating but otherwise viable cells. We report here that cell competition requires the function of the brinker (brk) gene, whose expression is normally repressed by Decapentaplegic (Dpp) signalling but is upregulated in slow-growing Minute/+ cells. Excess brk expression activates the c-Jun amino-terminal kinase pathway, which in turn triggers apoptosis in these cells. We propose that slow-proliferating cells upregulate Brk levels owing to a disadvantage in competing for, or in transducing, the Dpp survival signal. This sequence of events might represent a general mechanism by which weaker cells are eliminated from a growing population, and might serve as a method of controlling cell number and optimizing tissue fitness and hence organ function.

Animals↗
PubMed2002

[Vasovagal syncope in pediatric patients: a medium-term follow-up analysis].

INTRODUCTION AND OBJECTIVES: Little information is available on the evolution of pediatric patients with vasovagal syncope. We therefore aimed to assess the medium-term clinical outcome of children evaluated by tilt testing for syncope of unknown origin. PATIENTS AND METHOD: Fifty-one children under 17 years of age who had undergone tilt testing were identified from a data base and studied prospectively. Kaplan-Meier and Cox regression analyses were performed to estimate syncope-free survival, its predictors, and the relative risks of several patient subgroups. RESULTS: Forty-seven (92%) of the children were followed for a mean 21 9 months. The rate of recurrence of syncope was considerably lower than that estimated during history taking before the tilt test (19% vs 47%; p < 0.01). Although the low rate made it difficult to identify predictors, several potential predictors emerged from the multivariate analysis. Only the history of more than one syncope before the tilt test (vs. isolated syncope) was found to have independent predictive value (p = 0.04). The cumulative probability of recurrence projected for a period of 38 months was 66.2% (SEM = 16.5%) for children with more than one syncope before testing vs. 0% for those who had experienced only one. No other events occurred. CONCLUSIONS: The medium-term prognosis seems to be good for children with vasovagal syncope of unknown origin, given the low rate of recurrence, regardless of the results of tilt testing. The only predictor of recurrent syncope was pretest history, such that children with only one syncope before testing experience no recurrence and those with one or more episodes are estimated to have an increasingly higher likelihood of recurrence. These data may be useful for the recommending tilt testing and for planning therapy for children with vasovagal syncope.

Adolescent↗