P Serrano

Hospital Clínico Universitario Lozano Blesa, Zaragoza, Caesaraugusta, Aragon, Spain

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Publications (45)187.3 Total impact

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    Raquel Bailón, Pedro Serrano, Pablo Laguna
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    ABSTRACT: In this study, the influence of the time-varying mean heart rate (HR) and respiratory frequency in the ability of HR variability (HRV) indices to diagnose coronary artery disease has been studied. The autonomic nervous system activity has been assessed using a methodology that comprises correction of the HRV signal by the time-varying mean HR and redefinition of the classical high-frequency band to include respiratory frequencies above 0.4 Hz. The obtained clinical indices discriminate patients with coronary artery disease from patients with Framingham risk index lower than 5% with a moderate accuracy of 76%, which is lower than the reported in literature for HRV indices. We claim that time-varying mean HR and respiratory frequency, if not taken into account, introduce apparent improvement of diagnostic performance of HRV indices, adding information nonrelated to the autonomic nervous system activity, which is not what HRV is supposed to measure.
    Journal of electrocardiology 03/2011; 44(4):445-52. · 1.08 Impact Factor
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    ABSTRACT: The objective of the study was to identify clinical characteristics that enable non-cardiac chest pain to be differentiated from coronary artery disease. An observational case-control study was carried out in 40 patients with non-cardiac chest pain and a control group of 40 patients with coronary artery disease. Sociodemographic, medical and psychological variables were assessed. There was no difference in personality except in "emotional control", which was less in patients with non-cardiac chest pain. These patients had greater alexithymia and more frequently used coping strategies, such as religion and seeking medical help. Multivariate analysis showed that a predictive model comprising four variables (i.e., alexithymia, quality of life, and coping based on religion and seeking medical help) had a sensitivity of 85.4% and a specificity of 80.0%. This predictive model could be used as a screening test to discriminate between the two conditions.
    Revista Espa de Cardiologia 03/2010; 63(3):357-61. · 3.20 Impact Factor
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    ABSTRACT: The objective of the study was to identify clinical characteristics that enable non-cardiac chest pain to be differentiated from coronary artery disease. An observational case-control study was carried out in 40 patients with non-cardiac chest pain and a control group of 40 patients with coronary artery disease. Sociodemographic, medical and psychological variables were assessed. There was no difference in personality except in «emotional control», which was less in patients with non-cardiac chest pain. These patients had greater alexithymia and more frequently used coping strategies, such as religion and seeking medical help. Multivariate analysis showed that a predictive model comprising four variables (i.e., alexithymia, quality of life, and coping based on religion and seeking medical help) had a sensitivity of 85.4% and a specificity of 80.0%. This predictive model could be used as a screening test to discriminate between the two conditions.
    Revista Espa de Cardiologia 03/2010; 63(3):357-361. · 3.20 Impact Factor
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    ABSTRACT: This paper introduces a new clinical distortion index able to measure the decrease in diagnostic content in compressed echocardiograms. It is calculated using cardiologists' answers to a clinical testbed composed of two types of tests: one blind and the other semi-blind. This index may be used to compare clinical performance among video codecs from a clinical perspective. It can also be used to classify compression rates into useful and useless ranges, thus providing recommendations for echocardiogram compression. A study carried out in order to illustrate its use with Xvid video codec is also presented. The results obtained showed that, for 2D and M modes, the transmission rate should be at least 768 kbit s(-1) and for color Doppler mode and pulsed/continuous Doppler, 256 kbit s(-1).
    Physiological Measurement 05/2009; 30(5):429-40. · 1.50 Impact Factor
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    ABSTRACT: In this paper a new wireless decision-support system for haemodialysis patients using heart rate variability (HRV) is presented. The telemedicine system provides connectivity to three participant sites: the general practitioner or nurse at the point of care in the dialysis unit, the remote information and processing server and the cardiologist. At the clinical point of care, the nurse acquires the electrocardiogram (ECG) by using a tailored mobile telecardiology system as well as other relevant physiological information during the clinical procedure, and sends it to the information server. The received information is stored in a secure file server, linked to the patient database and the ECG signal is automatically analyzed by using advanced signal processing tools in the processing server, where a complete clinical results report is generated. The cardiologist can then be linked by means of a web browser to the information server to analyze these results for further clinical diagnosis support. The system has been applied to study HRV in patients undergoing haemodialysis. The clinical report consisted of trends for time- and frequency-domain HRV indexes and other supplementary information automatically calculated, which show the response of the electrical activity of the heart to the dialysis process and that can be helpful for the follow-up of these patients. The telecardiology framework has been successfully evaluated both by the patients and the hospital personnel showing a high compliance with the system. The design and implementation of the telecardiology system have followed the most recent advances in web technologies, biomedical information and storage standards and signal processing techniques. The presented system can be used as a telemedicine tool for clinical diagnosis support and could also be used in other clinical settings.
    Computer Methods and Programs in Biomedicine 01/2008; 88(3):273-82. · 1.56 Impact Factor
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    ABSTRACT: The study of the ultrastructure of spematozoa by means of transmission electron microscopy often presents with problems of interpretation according to the method employed, depending on whether samples are either centrifuged previously to the fixation or immersed in viscous gels. The major problems of interpretation are: changes in the location of vesicles originated during the maturation process and modifications in the adsorption of seminal plasma proteins to the sperm membrane surface. The aim of our study is to communicate an original new method for the treatment of spermatozoa for ultrastructural study. Our method is based on the use of animal tissues as biological containers, inside which the spermatic suspensions are included. We developed this method using fresh sperm samples taken from mature Rasa aragonesa rams. As biological container, we used 2.5-cm long segments of the intestine of 1-week-old chickens (Gallus gallus) (diameter around 4 mm). To avoid any influence of digestive enzymes of the mucosa on the sperm surface, we put each intestine fragment inside out by means of microdissection forceps under bifocal optical microscope and cold light. One of the edges was tied with thin suture silk. The sperm suspension was injected in the optimal experimental condition and amount. Finally, the still open edge of the intestine segment was tied with silk in the same way as the other segment edge. By using this technique, we can perform a suitable morphological study at an ultrastructural level. In addition, the functional relationship of the ultrastructural components of the target cells is correctly preserved.
    Microscopy Research and Technique 10/2007; 70(9):771-5. · 1.59 Impact Factor
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    ABSTRACT: The study of the ultrastructure of spematozoa by means of transmission electron microscopy (TEM) often presents with problems of interpretation according to the method employed, depending on whether samples are either centrifuged previously to the fixation or immersed in viscous gels. The major problems of interpretation are changes in the location of vesicles originated during the maturation process and modifications in the adsorption of seminal plasma proteins to the sperm membrane surface. The aim of our study is to communicate an original new method for the treatment of spermatozoa for ultrastructural study. Our method is based on the use of animal tissues as biological containers, inside which the spermatic suspensions are included. We developed this method using fresh sperm samples taken from mature Rasa Aragonesa rams. As biological container, we used 2.5-cm long segments of the intestine of 1-week-old chickens (Gallus gallus) (diameter around 4 mm). In order to avoid any influence of digestive enzymes of the mucosa on the sperm surface, we put each intestine fragment inside out by means of microdissection forceps under a bifocal optical microscope and cold light. One of the edges was tied with thin suture silk. The sperm suspension was injected in the optimal experimental condition and amount. Finally, the still-open edge of the intestine segment was tied with silk in the same way as the other segment edge. By using this technique, we can perform a suitable morphological study at an ultrastructural level. In addition, the functional relationship of the ultrastructural components of the target cells is correctly preserved.
    Microscopy Research and Technique 09/2007; 70(8):657-62. · 1.59 Impact Factor
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    ABSTRACT: This paper presents a new approach for ECG compression: to set a variable compression threshold to a value equal to the estimated noise in the ECG block. This approach presents several advantages. On the one hand, it solves the problem of where to place the compression threshold so as to obtain a compressed ECG signal preserving all its diagnostic properties. On the other hand, it provides a flexible threshold that is adapted block to block in order to remove noise from the block at the same time it considerably reduces the data to be stored or transmitted, depending on the application where the compression approach is being used. The new approach has been clinically tested using two kind of MOS tests: blind and semi-blind. Clinical evaluation using records from MIT-BIH Arrhythmia database carried out by three expert cardiologists has shown that the compressed signals produced with this compression approach preserves all their clinical diagnostic properties, being rated as very good, the maximum possible score.
    Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 02/2007; 2007:39-42.
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    ABSTRACT: Santiago Ramón y Cajal discovered a new type of cell related to the myenteric plexus and also to the smooth muscle cells of the circular muscle layer of the intestine. Based on their morphology, relationships and staining characteristics, he considered these cells as primitive neurons. One century later, despite major improvements in cell biology, the interstitial cells of Cajal (ICCs) are still controversial for many researchers. The aim of study was to perform an immunohistochemical and ultrastructural characterization of the ICCs in the rabbit duodenum. We have found interstitial cells that are positive for c-Kit, CD34 and nestin and are also positive for Ki67 protein, tightly associated with somatic cell proliferation. By means of electron microscopy, we describe ICCs around enteric ganglia. They present triangular or spindle forms and a very voluminous nucleus with scarce perinuclear chromatin surrounded by a thin perinuclear cytoplasm that expands with long cytoplasmic processes. ICC processes penetrate among the smooth muscle cells and couple with the processes of other ICCs located in the connective tissue of the circular muscle layer and establish a three-dimensional network. Intercellular contacts by means of gap-like junctions are frequent. ICCs also establish gap-like junctions with smooth muscle cells. We also observe a population of interstitial cells of stellate morphology in the connective tissue that sur-rounds the muscle bundles in the circular muscle layer, usually close to nervous trunks. These cells establish different types of contacts with the muscle cells around them. In addition, the presence of a single cilium showing a structure 9 + 0 in an ICC is demonstrated for the first time. In conclusion, we report positive staining c-Kit, CD34, nestin and Ki 67. ICCs fulfilled the usual transmission electron microscopy (TEM) criteria. A new ultrastructural characteristic of at least some ICCs is demonstrated: the presence of a single cilium. Some populations of ICCs in the rabbit duodenum present certain immunohistochemical and ultrastructural characteristics that often are present in progenitor cells.
    Journal of Cellular and Molecular Medicine 01/2007; 11(4):776-87. · 4.75 Impact Factor
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    ABSTRACT: The use of a tele-echocardiography system requires the use of lossy compression in order to reduce the transmission rates. That's the reason because guaranteeing clinical quality is a highly desired goal. In this paper we introduce two types of tests designed to obtain cardiologists' opinion and translate them to a clinical index. After that, we use this index to establish the recommendable transmission rate when using Xvid video codec in a tele-echocardiography system. Results show that the recommended rate depends on the echocardiography mode: 384 kbps for 2D and M mode, 256 kbps for color Doppler mode and 128 kbps for pulse and continuous Doppler mode.
    Computers in Cardiology, 2006; 10/2006
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    ABSTRACT: Guaranteeing reconstruction quality in ECG lossy compression is essential to obtain signals useful from a clinical point of view. In this paper we discuss the advantages and drawbacks of using two very well known mathematical error measures (PRD and RMS) in order to guarantee quality in threshold wavelet compression codecs that work segmenting the signal into blocks. We use two different error indices to analyze the results: mathematical (RMS global error) and clinical (MOS error). Although mathematical results conclude that guaranteeing RMS is better than PRD, clinical results have shown that the election is subordinated to the signal specific morphology.
    Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 02/2006; 1:6461-4.
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    ABSTRACT: A telecardiology framework for research and clinical decision support is presented. The telemedicine framework provides with connection to three participant sites: the physician at the point-of-care, the remote information centre and the specialized cardiologist. At the point of care, a physician acquires the ECG and other relevant information during the clinical intervention and sends it to the information server. Every ECG file received is stored in the file server, linked to the patient database and processed by the MATLAB-based tools in the processing server, which automatically generates a results report and informs the cardiologist of this fact. The system has been applied in the study of HRV in patients undergoing haemodialysis. In this particular case, the report consists of trends of time-domain and frequency-domain HRV indexes along dialysis and other supplementary information. The framework has been evaluated by patients and hospital personnel, who valued very positively the system. The designed framework has been shown as an efficient and helpful tool for clinical diagnosis support.
    01/2006;
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    ABSTRACT: Aspirin is valuable for preventing vascular events, but information about ulcer frequency is necessary to inform risk-benefit decisions in individual patients. To determine ulcer prevalence and incidence in a population representative of those given aspirin therapy and evaluate risk predictors. Patients taking aspirin 75-325 mg daily were recruited from four countries. Exclusions included use of gastroprotectant drugs or other non-steroidal anti-inflammatory drugs. We measured point prevalence of endoscopic ulcers, after quantitating dyspeptic symptoms. Incidence was assessed 3 months later in those eligible to continue (no baseline ulcer or reason for gastroprotectants). In 187 patients, ulcer prevalence was 11% [95% confidence interval (CI) 6.3-15.1%]. Only 20% had dyspeptic symptoms, not significantly different from patients without ulcer. Ulcer incidence in 113 patients followed for 3 months was 7% (95% CI 2.4-11.8%). Helicobacter pylori infection increased the risk of a duodenal ulcer [odds ratio (OR) 18.5, 95% CI 2.3-149.4], as did age >70 for ulcers in stomach and duodenum combined (OR 3.3, 95% CI 1.3-8.7). Gastroduodenal ulcers are found in one in 10 patients taking low-dose aspirin, and most are asymptomatic; this needs considering when discussing risks/benefits with patients. Risk factors include older age and H. pylori (for duodenal ulcer).
    Alimentary Pharmacology & Therapeutics 12/2005; 22(9):795-801. · 4.55 Impact Factor
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    ABSTRACT: Resumen cardiaco (HR) y las frecuencias centrales de dichas bandas. La coherencia media entre la frecuencia central de la banda HFext (0.15 Hz-HR/2) y la frecuencia respiratoria es de 0.64 en los voluntarios, de 0.47 en los sanos y de 0.44 en los isquémicos, y entre la frecuencia central de la banda HFext y el HR de 0.94 en los voluntarios, de 0.92 en los sanos y de 0.83 en los isquémicos, mostrándose un comportamiento diferente según el grupo.
    01/2005;
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    ABSTRACT: The aim of this work was to analyse the distribution pattern of S-100-immunoreactive elements in the upper eyelid of the sheep. This pattern may be of importance regarding the diagnosis and prognosis of eyelid tumours that are linked to deregulation of S-100 gene expression. Thirty upper eyelids taken from 15 adult male Ovis aries were studied by means of the peroxidase-antiperoxidase method for light microscopy. S-100-immunopositive cells were found in the eyelid edge. S-100-immunopositive steams and thinner fibres were found throughout the eyelid. These nerve processes typically were denser around glands, hair follicles and blood vessels. S-100-immunopositive elements may play a role as neuromodulator and also in the development of the vegetative innervation of the epithelium and its derivatives.
    Journal of Molecular Histology 07/2004; 35(5):457-62. · 1.55 Impact Factor
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    ABSTRACT: Observation on heart rate (HR) and heart rate variability (HRV) trends in exercise ECGs lead us to hypothesize that some correlation exists between the evolution of HR and the dominant HRV frequency, which may differ in ischemic and healthy subjects. The ECGs recordings from stress test trials were collected and clustered into four groups: ischemic (positive coronary angiography), non-ischemic, volunteers and healthy (non-ischemic patients with 10 year predicted risk of CAD < 5%, according to the Framingham index). A new index based on the coherence between HR and dominant frequency of the time-frequency HRV was proposed in this work to add diagnostic information to exercise testing, obtaining statistically significant differences (p<10<sup>-5</sup>) between ischemic and rest of the groups.
    Computers in Cardiology, 2003; 10/2003
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    ABSTRACT: Several indexes have been reported to improve the accuracy of exercise test electrocardiogram (ECG) analysis in the diagnosis of coronary artery disease (CAD), compared with the classical ST depression criterion. Some of them combine repolarisation measurements with heart rate (HR) information (such as the so-called ST/HR hysteresis); others are obtained from the depolarisation period (such as the Athens QRS score); finally, there are heart rate variability (HRV) indexes that account for the nervous system activity. The aim of this study was to identify the best exercise ECG indexes for CAD diagnosis. First, a method to automatically estimate repolarisation and depolarisation indexes in the presence of noise during a stress test was developed. The method is divided into three stages: first, a preprocessing step, where QRS detection, filtering and baseline beat rejection are applied to the raw ECG, prior to a weighted averaging; secondly, a post-processing step in which potentially noisy averaged beats are identified and discarded based on their noise variance; finally, the measurement step, in which ECG indexes are computed from the averaged beats. Then, a multivariate discriminant analysis was applied to classify patients referred for the exercise test into two groups: ischaemic (positive coronary angiography) and low-risk (Framingham risk index < 5%). HR-corrected repolarisation indexes improved the sensitivity (SE) and specificity (SP) of the classical exercise test (SE = 90%, SP = 79% against SE = 65%, SP = 66%). Depolarisation indexes also achieved an improvement over ST depression measurements (SE = 78%, SP = 81%). HRV indexes obtained the best classification results in our study population (SE = 94%, SP = 92%) by means of the very high-frequency power (VHF) (0.4-1 Hz) at stress peak.
    Medical & Biological Engineering & Computing 09/2003; 41(5):561-71. · 1.79 Impact Factor
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    ABSTRACT: We have studied the autoradiographic uptake of 65Zn in the cerebellum and brainstem of the rat, contrasting these results with Timm's positivity in these structures. Both, autoradiographic uptake and histochemical positivity, have demonstrated Zinc in a location that could be accepted as in climbing fibres and glomeruli of the cerebellum cortex, and also in brainstem neurons that project their axons to the cerebellum cortex, suggesting a circuit where zinc may act as a neuromodulator.
    Histology and histopathology 05/2003; 18(2):467-73. · 2.28 Impact Factor
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    ABSTRACT: To evaluate the risk of upper gastrointestinal bleeding associated with non-aspirin cardiovascular drug therapy, common analgesics and individual nonsteroidal anti-inflammatory drugs (NSAIDs). The case group was made up of 1122 consecutive patients admitted with bleeding from a peptic lesion. The 2231 control subjects consisted of 1109 patients hospitalized for other reasons and 1122 outpatients from the same geographical area. The relative risk was calculated by unconditional logistic regression after adjusting for confounding factors. The use of the antiplatelet agent triflusal, and other commonly used cardiovascular drugs, such as beta-receptor blockers and calcium channel blockers, was not associated with increased risk of upper gastrointestinal bleeding. The use of angiotensin-converting enzyme inhibitors reduced the risk of bleeding by 30% (odds ratio 0.7; 95% confidence interval 0.5-0.96). Use of ketorolac (odds ratio 59.4; 95% confidence interval 7.7-454) and piroxicam (odds ratio 19.6; 95% confidence interval 9.3-35.3) carried the highest risk. Use of paracetamol and tramadol was not associated with increased risk of bleeding, but the non-narcotic agent metamizol was associated with a small increase in risk of upper gastrointestinal bleeding (odds ratio 2.6; 95% confidence interval 1.3-5.2). The use of the antiplatelet agent triflusal and other cardiovascular drugs apart from low-dose aspirin was not associated with gastrointestinal bleeding. The use of either NSAIDs or aspirin increased the risk of gastrointestinal bleeding but, among the analgesics, only metamizol induced a small increase in the risk of gastrointestinal bleeding.
    European Journal of Gastroenterology & Hepatology 03/2003; 15(2):173-8. · 1.92 Impact Factor
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    ABSTRACT: Most patients with vascular-occlusive diseases benefit from low-dose aspirin (75-325 mg/day). However, they have an increased risk of upper gastrointestinal bleeding (UGIB). To analyse the incidence and factors influencing the occurrence of UGIB in patients taking low-dose aspirin for the prevention of cardiovascular diseases outside clinical trials. We studied 903 consecutive patients discharged on low-dose aspirin from the Cardiology Department of a general hospital. Data were collected from medical charts and structured telephone interviews. Forty-one patients (4.5%) presented with UGIB requiring hospitalization during follow-up (45 +/- 22 months). The incidence of UGIB was uniform during follow-up (1.2 UGIB per 100 patient years). Multivariate analysis showed that a history of peptic ulcer or UGIB [risk ratio: 3.1, 95% CI: (1.5-6.5)] and aspirin dose (per 100 mg/day) [1.8 (1.5-2.9)] was associated with higher risk of UGIB. On the other hand, antisecretory [0.22 (0.07-0.75)] and nitrovasodilator drugs [0.73 (0.55-0.96)] were associated with a decreased risk. Cardiovascular patients on long-term low-dose aspirin have a stable risk of major UGIB, which is higher than published controlled clinical trials. Antisecretory and nitrovasodilator drugs protect from UGIB, whereas previous peptic ulcer or UGIB and higher doses of aspirin increase the risk.
    Alimentary Pharmacology & Therapeutics 12/2002; 16(11):1945-53. · 4.55 Impact Factor

Publication Stats

826 Citations
187.30 Total Impact Points

Institutions

  • 2002–2010
    • Hospital Clínico Universitario Lozano Blesa, Zaragoza
      Caesaraugusta, Aragon, Spain
    • Servicos Medicos Cardio
      San Paulo, São Paulo, Brazil
  • 2000–2009
    • University of Zaragoza
      • Department of Electrical Engineering and Communications
      Caesaraugusta, Aragon, Spain