Biomedical subjects

Miguel A Fernández

Publications and source records attributed to Miguel A Fernández.

3 recordsLinked to original sources

PubMed2006

[Stress echocardiography in the identification of left anterior descending coronary artery disease in patients with inferior myocardial infarction and a positive exercise electrocardiography result].

INTRODUCTION AND OBJECTIVES: In patients with an inferior myocardial infarction (IMI), ST-segment depression in left precordial leads during exercise electrocardiography (ExECG) has been associated with left anterior descending coronary artery (LADCA) disease. The aim of this study was to assess the value of stress echocardiography in identifying LADCA disease in patients with IMI and a highly abnormal ExECG result. METHODS: The study included patients with an IMI and an abnormal ExECG result whose coronary angiography findings were available. A highly abnormal ExECG result was defined as ST-segment depression in three or more leads, including V5. The wall motion score index was calculated and each patient was evaluated echocardiographically for ischemia in LADCA territory. RESULTS: Of 241 patients who underwent stress ECG, 100 (mean age 57 [11] years) met inclusion criteria. Some 38 had significant LADCA stenosis and, in 75, ExECG gave a highly abnormal result. The sensitivity, specificity and accuracy of a highly abnormal ExECG result for detecting LADCA disease were 74% (60%-88%), 26% (15%-37%), and 44% (34%-54%), respectively. Echocardiographic detection of ischemia had similar sensitivity, at 74%, but higher specificity, at 92% (P< .001), and accuracy, at 85% (P< .001). Multivariate analysis of clinical, exercise test, and stress echocardiography variables revealed that the only independent predictors of LADCA disease were age (OR=1.070), recent IMI (OR=0.136), and ischemia in LADCA territory (OR=19.9). CONCLUSIONS: Stress echocardiography is a good noninvasive technique for detecting LADCA disease in patients with an IMI. The diagnostic accuracy of a highly abnormal ExECG result is not sufficient for its use in this clinical setting.

Adult↗

PubMed2003

Role of hydrocolloids in the creaming of oil in water emulsions.

The influence of guar gum and xanthan gum on the creaming of 10% oil in water emulsions has been investigated. The presence of very low concentrations of the polysaccharides (typically < approximately 0.075%) was found to induce depletion flocculation of the emulsion droplets and increased the rate of creaming. However, at higher polysaccharide concentrations (typically > approximately 0.1%) the creaming rate was reduced due to the increased viscosity of the aqueous phase. For most systems a delay period was noted before creaming started, which was found to be dependent on the zero shear viscosity of the continuous phase and independent of polysaccharide type. The delay period increased significantly at zero shear viscosities approaching 1 Pa s. A mathematical model has been used to fit the creaming rate profiles and a simple exponential relationship obtained between delay time and polysaccharide concentration.

Chemical Phenomena↗

PubMed2003

On motion detection through a multi-layer neural network architecture.

A neural network model called lateral interaction in accumulative computation for detection of non-rigid objects from motion of any of their parts in indefinite sequences of images is presented. Some biological evidences inspire the model. After introducing the model, the complete multi-layer neural architecture is offered in this paper. The architecture consists of four layers that perform segmentation by gray level bands, accumulative charge computation, charge redistribution by gray level bands and moving object fusion. The lateral interaction in accumulative computation associated learning algorithm is also introduced. Some examples that explain the usefulness of the system we propose are shown at the end of this article.

Motion Perception↗