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Biomedical subjects

I Tejero

Publications and source records attributed to I Tejero.

12 recordsLinked to original sources
PubMed2006

Characterisation of solid and liquid fractions of dairy manure with regard to their component distribution and methane production.

Dairy manure with a total solids content of 77.2g TS/l was separated by means of screening and coagulation-flocculation treatments, using CaO as coagulant and a cationic polyacrylamide as flocculant, obtaining liquid and solid fractions. The solid fraction separated contained 33.4% of the initial total mass of dairy manure plus chemical solutions, containing also 75.2% of the TS, 80.4% of the VS, 58.5% of the total Kjeldahl nitrogen (TKN) and 87.4% of the total phosphorus (P(T)) present in the initial dairy manure. 83.7% of the liquid fraction chemical oxygen demand (COD) was anaerobically biodegradable (COD(BD)). Methane production for the separated liquid fraction was 0.604l CH4 NCTP/g VS added, being 0.307 and 0.371l CH4 NCTP/g VS added for dairy manure and screened dairy manure, respectively. The characteristics of this liquid fraction would allow its treatment in high loading anaerobic reactors having shorter hydraulic retention times, smaller reactor size and a higher methane volumetric production rate than conventional anaerobic reactors treating either manure or screened manure.

Anaerobiosis↗
PubMed2004

Environmental engineering education in Spain.

There is a growing demand for engineers and technologists who show multidisciplinary expertise to deal with environmental issues. As a result of this demand, most countries are adapting their old university programs on environmental engineering education. In Spain an official environmental engineering degree does not yet exist, but the Council of Universities is working to present a proposal, based on Bologna agreement concepts. The paper summarizes not only the future perspectives of environmental engineering education in Spain, but also the evolution of the approach during the last decades, which includes the role of the private initiative, the environmental sciences degree, and the intensification in different traditional engineering degrees. Finally, the paper briefly details and compares the syllabus developed in the only four Spanish universities where environmental engineering is offered as a non-official post-graduate course lasting two years.

Curriculum↗
PubMed2002

Detention storage volume for combined sewer overflow into a river.

This article discusses the storage volume needed in a combined sewer system tank in order to preserve the water quality. There are a lot of design criteria which do not take into account the conditions of the receiving water, and as a result are inappropriate. A model was used to simulate the performance of a theoretical combined sewer system where a tank was located downstream. Results were obtained from the overflows produced by the rain recorded in Santander (Spain) for 11 years, with several combinations of storage volume and treatment capacity in the wastewater treatment plant. Quality criteria were also proposed for faecal coliforms, BOD, and total nitrogen to evaluate the effects from the overflows in the river water quality. Equations have been obtained which relate the number of overflows, the storage volume and the treatment plant capacity. The bacteriological pollution, quantified by means of faecal coliforms, was the analytical parameter which produced the most adverse effects in the river, so that more storage volume is needed (45 to 180 m3 ha(-1) net) than with other simulated pollutants (5 to 50 m3 ha(-1) net for BOD, and less than 4 m3 ha(-1) net for the total nitrogen). The increase in the treatment plant's capacity, from two to three times the flow in dry weather, reduces the impact on the river water in a more effective way, allowing a reduction of up to 65% in the number of overflows rather than increasing the storage volume.

Enterobacteriaceae↗
PubMed1996

[Long-term clinical course of acute myocarditis. Prospective study of a series of 99 patients (1987-1995)].

BACKGROUND: The natural history of acute myocarditis is not well known. The aim of our study was to assess the spontaneous outcome of patients with this disease and its possible relation with progression to chronic dilated cardiomyopathy. METHODS: With this aim, we have carried out a prospective study of 99 patients consecutively diagnosed with acute myocarditis in our hospital from 1987 to April 1995, with a mean follow-up of 34 +/- 25 months. Acute myocarditis was diagnosed by clinical, echocardiographic and isotopic (detection of myocite damage) data, in absence of any other cardiac lesion. RESULTS: Mean age was 26 +/- 17 years; 70% of the patients were male. Initial symptoms were dyspnea in 58% of the patients, chest pain in 33% and arrhythmias in 9%. Severe heart failure was present in 62% of the patients, ventricular arrhythmias in 16% and supraventricular arrhythmias in 16%. Cardiothoracic index was 0.50 +/- 0.07. Left ventricular ejection fraction was 0.40 +/- 0.18, although in 44% of the patients it was lower than 0.30. Immunosuppressive therapy was not used in any case. Outcome was favorable in 70% of the patients, who had a normal ejection fraction, while 13% died or needed heart transplantation during follow-up and 17% progressed to stable chronic dilated cardiomyopathy. Final ejection fraction was 0.53 +/- 0.17, significantly higher than the initial, 0.40 +/- 0.18 (p < 0.05); this improvement in ejection fraction was mainly observed during the first month after diagnosis (0.49 +/- 0.18). The proportion of patients with an ejection fraction of less than 0.30 decreased from 44% to 21% at the end of follow-up. CONCLUSIONS: Spontaneous outcome of acute myocarditis is good in the majority of patients, although an unfavourable evolution was observed in almost 30% of the patients (death, need of heart transplantation or chronic dilated cardiomyopathy). Improvement in ventricular function mainly occurs at short-term, during the first month of evolution in our study.

Acute Disease↗
PubMed1995

Balloon-expandable stent repair of severe coarctation of aorta.

Experimental studies have shown that stents implanted at the aorta become incorporated within the aortic wall and can be further expanded in growing animals. This study evaluates the feasibility and immediate results of balloon-expandable stent implantation in 10 patients with severe coarctation of aorta. The ages of the patients ranged from 1 month to 43 years; 1 was an infant, 8 were children (mean age 5.3 +/- 4 years), and 1 was an adult. All had an unfavorable anatomy for balloon angioplasty; 9 had isthmus hypoplasia. Balloon predilation was first performed and its immediate effect evaluated. Then a balloon-expandable stent that was 30 mm long and covered the isthmus and coarctation levels was deployed, and it was further expanded to the preselected final diameter (12 +/- 4 mm). A final hemodynamic and angiographic evaluation was then obtained. Full deployment of an incompletely expanded and distally displaced stent in the infant led to aortic disruption that was controlled by a second stent covering the disrupted zone and the isthmus. After balloon angioplasty alone was done, the mean gradient (43 +/- 12 vs 31 +/- 10 mm Hg) and the percentage stenosis (72% +/- 11% vs 54% +/- 11%) had an insufficient decrease. However, after stent implantation was done, the gradient almost disappeared (mean 2 +/- 3 mm Hg). The angiographic stenosis disappeared in 7 patients and was markedly reduced in 3. The ratio of isthmus/descending aorta changed from 0.65 +/- 0.14 to 1 +/- 0.08 (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1995

Heart rate variability and inappropriate sinus tachycardia after catheter ablation of supraventricular tachycardia.

Sinus tachycardia has been reported after radiofrequency catheter ablation of supraventricular tachycardia. Frequently, these patients require beta-blocking agents for symptomatic control. The purpose of this study was to evaluate prospectively the incidence of inappropriate sinus tachycardia and heart rate variability after ablation of atrioventricular nodal reentrant tachycardia and accessory pathways. Patients undergoing ablation had 24-h ambulatory monitoring ECG (Holter) performed before the procedure, on the day of the ablation, and 3 months afterwards. There were 170 patients, mean age 48 +/- 23 years; 93 were female. A complete study of the 24-h Holter with analysis of heart rate variability: SD, rMSSD, pNN50, high and low frequency was obtained. There was a low prevalence of inappropriate sinus tachycardia after the ablation procedure (10 of 170 patients: five with four atrioventricular nodal reentry, with posteroseptal accessory pathways and one of the latter following ablation of the left accessory pathway). There was no modification of time and frequency domain parameters of heart rate variability in the remaining patients who underwent radiofrequency ablation. Holter monitoring 3 months after ablation showed that parameters of heart rate and heart rate variability had normalized in patients who had developed inappropriate sinus tachycardia. Inappropriate sinus tachycardia may be initiated by both radiofrequency ablation of atrioventricular nodal reentrant tachycardia and radiofrequency ablation of posteroseptal accessory pathways. Specific damage to the posteroseptal region is responsible for these changes, which usually recover spontaneously after 3 months.

Adult↗
PubMed1995

[Acute myocarditis with severe cardiac dysfunction in the pediatric population. The evolution and differential characteristics with respect to adult myocarditis].

AIMS: The aim of our study was to assess the spontaneous outcome of acute myocarditis associated with severe cardiac dysfunction in children, as well as to compare these features with those occurring in adult patients. METHODS: Fifty patients consecutively diagnosed of acute myocarditis during the last 7 years in our hospital were studied; 15 patients were children younger than 14 years, and 35 were adults. Immunosuppressive therapy was not used in any patient. RESULTS: Mean age was 2 +/- 3 years in children, ranging from 2 months to 12 years. One patient required temporary pacing for a third-degree atrioventricular block, while the remaining 14 children had severe congestive heart failure, with a left ventricular ejection fraction of 30 +/- 12% (16 to 44%). After a mean follow-up of 21 +/- 26 months, only 3 children died, at 1, 4 and 10 months after the initial diagnosis. Death was sudden in all 3 patients. Left ventricular ejection fraction rose to 45 +/- 14% at 1 month after diagnosis, and to 58 +/- 15% at the end of follow-up. Unfavorable evolution (death or evolution to chronic dilated cardiomyopathy, with a left ventricular ejection fraction < 45%) occurred in 6 children (40%) at 1 month after diagnosis and in only 4 (25%) at the end of follow-up. The 9 children with 1-month favorable outcome were alive and had an ejection fraction > 45% at long-term, while only 2 of the 6 children with 1-month unfavorable outcome were alive and had an ejection fraction > 45% at long-term. Only the 3 children who died had an ejection fraction < 30% at 1-month. Favorable outcome was more frequent in children that in adult patients with acute myocarditis (75% versus 46%). CONCLUSIONS: The outcome of acute myocarditis with severe cardiac dysfunction was favorable in a majority of pediatric patients; this favorable evolution was less frequent in adults. Patients in whom left ventricular ejection fraction did not increase at short-term had a higher risk of death, and they should probably be considered for heart transplantation.

Acute Disease↗
PubMed1994

[Infectious endocarditis in non-addict patients without predisposing heart disease. Differential features].

INTRODUCTION AND AIMS: Although uncommonly, infective endocarditis in non-addict patients may involve people without predisponente heart disease. The aim of our study was to assess the clinical and prognostic features of this type of endocarditis and to compare them with those of the more common type of endocarditis with underlying lesion. METHODS: With this aim, we have reviewed 71 consecutive cases of non-addict infective endocarditis diagnosed in our hospital in the last 7 years; there was no preexisting cardiac lesion in 9 patients (13% of all endocarditis and 21% of native valve endocarditis), while underlying heart disease, including mitral valve prolapse, was present in the remaining 62 patients. RESULTS: Mean age was significantly lower in 9 patients without preexistent lesion (28 +/- 18 versus 46 +/- 17 years, p < 0.01), while there was no differences for gender. Infection involved the aortic valve in 56%, the tricuspid or pulmonary valve in 33% and the mitral valve in only 11% of the patients without underlying cardiopathy (for 44%, 4% and 49%, respectively, in patients with cardiopathy). Staphylococcus aureus caused 67% of cases in patients without cardiopathy and only 9% in those with cardiopathy. Surgery was required in a similar proportion by both groups of patients (55% and 56%), although mortality was more than twice higher in patients with prior cardiac lesions (25% versus 11%). CONCLUSIONS: A significant proportion of non-addict infective endocarditis involves patients without predisponente heart disease. These cases have some differential features (younger age, aortic and right heart valves involvement, S. aureus as the main causative agent and lower mortality) in comparison to those of endocarditis in patients with underlying cardiopathy.

Adolescent↗
PubMed1989

Abrupt homeostatic responses to transient intracardiac occlusion during balloon valvuloplasty.

The present study analyzes the hemodynamics of intracardiac occlusive periods during balloon mitral or aortic valvuloplasty and compares them with immediate plasma levels of atrial natriuretic factor (ANF), vasopressin and renin activity. Forty-nine patients were studied; 33 of them had mitral stenosis and 16 had aortic stenosis. The mean age was 52 +/- 17 years. During dilations pressures were monitored from the ascending aorta and left atrium. Plasma levels of ANF, vasopressin and renin were serially determined at baseline, after diagnostic procedures, within 15 to 30 seconds after the first 2 occlusive dilations, and 1 and 7 hours later. There were no significant changes in plasma renin throughout the study stages. ANF and vasopressin significantly increased after the dilations. These hormonal changes were related to the significant hemodynamic changes observed during intracardiac occlusion. The left atrial pressure correlated directly and significantly (r = 0.54, p less than 0.001) with plasma ANF levels throughout the conditions. On the other hand, the plasma vasopressin also correlated (r = 0.76, p less than 0.001) with systemic pressure in an exponential fashion. These findings show that abrupt releases of ANF and vasopressin occur immediately after intracardiac occlusive periods as a response to the acute and transient hemodynamic changes observed.

Adolescent↗