Incidence, predictors, and effects of acute kidney injury after percutaneous valve implantation.

BACKGROUND: Acute kidney injury is a common complication after surgical aortic replacement and entails a worse prognosis. Percutaneous valve implantation is an alternative to surgical replacement. We sought to elucidate incidence, predictors, and effects of acute kidney injury after percutaneous aortic valve implantation. METHODS: A cohort of consecutive patients who underwent percutaneous aortic valve implantation at one center were studied, excluding those who died in the first 24 hours and those on prior hemodialysis. RESULTS: A total of 131 patients (age, 80.8 ± 6 years; 42% male; Euroscore II, 10.27 ± 6.9) were included. Acute kidney injury was defined as a reduction >25% in glomerular filtration rate (GFR). GFR was 62.09 ± 22 mL/min/1.73 m² at baseline, 62.7 ± 25 mL/min/1.73 m² after the procedure, and 68.03 ± 25 mL/min/1.73 m² at discharge. Acute kidney injury appeared in 17 patients (13%). Of these, 11 recovered and only 6 (4.5%) showed impaired GFR >25% upon discharge. Patients with acute kidney injury showed longer hospitalization length (median 7 days [IQR, 5-12 days] vs 3 days [IQR, 2-6 days]; P=.01) and higher 30-day mortality rate (17.6% vs 0.9%; P=.01). The only independent predictor for acute kidney injury development was Euroscore II (odds ratio, 1.192; confidence interval, 1.042-1.326; P=.01). CONCLUSION: Incidence of acute kidney injury after transcatheter aortic valve implantation was 13% in our cohort. Patients with acute kidney injury showed longer hospitalization and higher 30-day mortality rate. Euroscore II was an independent predictor of acute kidney injury.

Recovery of global systolic function after primary angioplasty. Influence of coronary flow velocity reserve measured by transthoracic echocardiography.

BACKGROUND: Our objective were to know whether coronary flow velocity reserve measured by transthoracic Doppler echocardiography, as marker of microvascular integrity, affects the recovery of global systolic function. Secondly, we intended to define the best cut-off point of coronary flow velocity reserve to predict recovery of global systolic function. METHODS: We studied 57 patients with coronary flow recorded by transthoracic Doppler echocardiography, after suffering a first anterior acute myocardial infarction and undergoing a successful primary percutaneous coronary intervention (TIMI 3 flow). We measured, at discharge and at 1 month: ejection fraction, volume indexes and anterior wall motion score index. Coronary flow in left anterior descending artery was detected by transthoracic Doppler echocardiography and coronary flow velocity reserve was calculated. RESULTS: After applying ROC curves, 1.54 was the best cut-off value of coronary flow velocity reserve for detection of recovery of global systolic function. Ejection fraction only increased significantly in patients with normal coronary flow velocity reserve. Only end-systolic volume index increased significantly at 1 month in patients with impaired coronary flow velocity reserve. CONCLUSION: We showed that coronary flow velocity reserve, measured by transthoracic Doppler echocardiography, influence the recovery of global systolic function, mainly by ventricular dilation. Furthermore, a quite lower value of coronary flow velocity reserve than that used for diagnostic purpose should be used to predict improvement of systolic function.

[Comparative study of treatment with quinupristin-dalfopristin alone or in combination with gentamicin, teicoplanin, imipenem or levofloxacin in experimental endocarditis due to a multidrug-resistant Enterococcus faecium]. / Comparacion de la eficacia de quinupristina-dalfopristina en monoterapia y combinada con gentamicina, teicoplanina, imipenem o levofloxacino en un modelo experimental de endocarditis por Enterococcus faecium multirresistente.

The incidence of multidrug-resistant Enterococcus faecium is increasing despite advances in antibacterial therapy. Thus, new antibiotics are required to treat hospital- or community-acquired infections caused by these multidrug-resistant organisms. The aim of this study was to compare the therapeutic efficacy of quinupristin-dalfopristin (QD) alone, or in combination with gentamicin (G), teicoplanin (T), imipenem (I) or levofloxacin (L) against a strain of multidrug-resistant E. faecium in an experimental model of aortic valve endocarditis in rabbits. The study group consisted of 28 control animals. Eighty-two animals were treated with one of the following antibiotic regimens: G1: 18 animals QD (30 mg/kg/8 h); G2: 18 animals QD+G (6 mg/kg/12 h); G3: 16 animals QD+T (20 mg/kg/12 h); G4: 14 animals QD+I (60 mg/kg/8 h); and G5: 16 animals QD+L (20 mg/kg/12 h). The response to therapy was determined by the comparison of the number of CFU/g of E. faecium in each vegetation. In vitro, time-kill studies looking for synergy for the combinations that showed better efficacy in vivo were done. The sensitivity of the strain was intermediate to QD, resistant to T and I, and sensitive to L. There was no high-level resistance to G. QD alone revealed a significant decrease (p <0.001) in the CFU/g in the control group (9.49 vs. 7.31). There were no differences in the average of CFU/g between the QD alone (G1), QD+G (G2) and QD+T (G3) groups. These three groups revealed a significant difference in decrease of CFU/g respect of the group control (p <0.001). There were no differences in the average of CFU/g between QD+I (G4) and QD+T (G5). These two groups revealed the greatest decrease in average CFU/g (G4: 4.38 and G5: 4.04) with differences respect of the group control (p <0.0001) and respect of the groups G1, G2 and G3 (p <0.001). We did not detect any alteration of MIC from QD in the course of the treatment for either of the final isolations. Only the time kill corresponding to concentrations of I 32 mg/l (0.25 x MIC) and QD 1 mg/l (0.25 x MIC presents a descending slope in the curve at 4 and 8 h, suggesting an early synergy phenomenon, which was lost after 8 h. In light of these results, the combination QD with I and L may be considered suitable alternatives for the treatment of multiresistant E. faecium.

Comparación de la eficacia de quinupristina-dalfopristina en monoterapia y combinada con gentamicina, teicoplanina, imipenem o levofloxacino en un modelo experimental de endocarditis por Enterococcus faecium multirresistente / Comparative study of treatment with quinupristin-dalfopristin alone or in combination with gentamicin, teicoplanin, imipenem or levofloxacin in experimental endocarditis due to a multidrug-resistant Enterococcus faecium

La incidencia de infecciones por Enterococcus faecium multirresistentes va aumentando a pesar de los avances que se han producido en antibioticoterapia.Por ello, se necesitan nuevos antibióticos para tratar las infecciones nosocomiales o comunitarias causadas por este microorganismo.El objetivo principal del presente estudio fue comparar la eficacia de quinupristina-dalfopristina (QD), sola o combinada con gentamicina(G), teicoplanina (T), imipenem (I) o levofloxacino (L), en un modelo de endocarditis experimental en conejos por E. faecium multirresistente.Se utilizaron 110 animales, 28 como grupo control y 82 como grupos terapéuticos, que fueron G1: 18 animales con QD (30mg/kg/8 h); G2: 18 con QD+G (6 mg/kg/12 h); G3: 16 con QD+T (20 mg/kg/12 h); G4: 14 con QD+I (60 mg/kg/8 h); y G5: 16 con QD+L(20 mg/kg/12 h). Se valoró la respuesta terapéutica comparando la concentración de E. faecium en las vegetaciones cardiacas expresada comolog10 de las unidades formadoras de colonias por gramo de tejido (UFC/g). Se realizaron pruebas de cinética de letalidad bacteriana paralas asociaciones que mostraron mejor comportamiento in vivo: QD + I y QD + L. El patrón de sensibilidad de la cepa utilizada fue: sensiblepara L, intermedia para QD, resistente para T e I, y sin resistencia de alto grado para G. El tratamiento con QD logró una reducción significativa(p <0.001) en las UFC/g respecto al grupo control (9,49 frente a 7,31). No hubo diferencias significativas entre los grupos G1 (QDsola), G2 (QD + G) y G3 (QD + T), consiguiendo estos tres grupos una redución significativa respecto del grupo control (p <0.001). No hubodiferencias entre G4 (QD + I) y G5 (QD + L). Estos dos grupos se mostraron como los más eficaces en reducir la media de UFC/g en lasvegetaciones cardiacas (G4: 4,38 y G5: 4,04), con p <0.0001 respecto al grupo control y p <0.001 respecto a G1, G2 y G3. No se detectóningún cambio en la CMI de QD durante el tratamiento. Sólo la curva de letalidad correspondiente a la concentración de I de 32 mg/l (0,25x CMI) con QD 1 mg/l (0,25 x CMI) presentó una curva descendente a las 4 y 8 horas, sugiriendo una sinergia precoz que se perdió a las 8 horas.A la vista de estos resultados, la combinación de QD con I o L podría considerarse como alternativa terapéutica en la endocarditis porE. faecium multirresistente

The incidence of multidrug-resistant Enterococcus faecium is increasing despite advances in antibacterial therapy. Thus, new antibiotics arerequired to treat hospital- or community-acquired infections caused by these multidrug-resistant organisms. The aim of this study was tocompare the therapeutic efficacy of quinupristin-dalfopristin (QD) alone, or in combination with gentamicin (G), teicoplanin (T), imipenem(I) or levofloxacin (L) against a strain of multidrug-resistant E. faecium in an experimental model of aortic valve endocarditis in rabbits. Thestudy group consisted of 28 control animals. Eighty-two animals were treated with one of the following antibiotic regimens: G1: 18 animalsQD (30 mg/kg/8 h); G2: 18 animals QD+G (6 mg/kg/12 h); G3: 16 animals QD+T (20 mg/kg/12 h); G4: 14 animals QD+I (60 mg/kg/8 h);and G5: 16 animals QD+L (20 mg/kg/12 h). The response to therapy was determined by the comparison of the number of CFU/g of E. faeciumin each vegetation. In vitro, time-kill studies looking for synergy for the combinations that showed better efficacy in vivo were done.The sensitivity of the strain was intermediate to QD, resistant to T and I, and sensitive to L. There was no high-level resistance to G. QD alonerevealed a significant decrease (p <0.001) in the CFU/g in the control group (9.49 vs. 7.31). There were no differences in the average of CFU/gbetween the QD alone (G1), QD+G (G2) and QD+T (G3) groups. These three groups revealed a significant difference in decrease of CFU/grespect of the group control (p <0.001). There were no differences in the average of CFU/g between QD+I (G4) and QD+T (G5). These twogroups revealed the greatest decrease in average CFU/g (G4: 4.38 and G5: 4.04) with differences respect of the group control (p <0.0001)and respect of the groups G1, G2 and G3 (p <0.001). We did not detect any alteration of MIC from QD in the course of the treatment for eitherof the final isolations. Only the time kill corresponding to concentrations of I 32 mg/l (0.25 x MIC) and QD 1 mg/l (0.25 x MIC presents adescending slope in the curve at 4 and 8 h, suggesting an early synergy phenomenon, which was lost after 8 h. In light of these results, thecombination QD with I and L may be considered suitable alternatives for the treatment of multiresistant E. faecium

[Regenerative medicine with adult stem cells]. / Medicina regenerativa con células madre adultas.

The present state of clinical regenerative medicine with adult stem cells in the cardiology, digestive, corneal and neurological fields are reviewed. From the cardiology point of view, there is clinical experience with bone marrow stem cells and peripheral blood cells and with skeletal myoblasts. At present, the adult stem cells (bone marrow hematopoietic or mesenchymal) constitute the best option for the regeneration of heart tissue, the clinical studies showing favorable results without ethical or safety problems. Most of the studies with skeletal myoblasts have also been demonstrated to significantly contribute to improve heart function, above all, the systolic one. However they have the disadvantage that has not been totally clarified that they induce malignant ventricular arrhythmias. In either case, the clinical studies are in the initial phase and new studies, above all randomized, are necessary. In the digestive field, there is the pioneer experience of the Hospital La Paz on the use of stem cells from abdominal fat in the treatment of fistulous condition of patients with Crohn's disease. In ophthalmology, the limbal corneal transplant is a recognized practice, using cells from the contralateral eye when the damage is in a single eye and cells from a donor when the damage is bilateral. Finally, in the neurological field, different zones of the adult mammal brain where there are stem cells have been identified: the hippocampus, subventricular zone, olfactory bulb and periependymal zone of the spinal cord. On the other hand, neurons may be obtained from adult stem cells from other tissues, such as the bone marrow or adipose tissue, which means a practically unendable source of neural precursors, either by direct implant after their selection or after their in vitro culture. However, most of the experimentation is animal up to now, clinical trails on safety in amyotrophic lateral sclerosis are now being initiated.

Medicina regenerativa con células madre adultas / Regenerative medicine with adult stem cells

En este trabajo se revisa el estado actual de la medicina regenerativa clínica con células madre de adulto en los campos cardiológico, digestivo, corneal y neurológico. Desde el punto de vista cardiológico existe experiencia clínica con progenitores de médula ósea y células de sangre periférica, así como con mioblastos esqueléticos. En el momento actual las células madre del adulto (hematopoyéticas o mesenquimales de médula ósea) constituyen la mejor opción para la regeneración del tejido cardíaco, mostrando los estudios clínicos resultados favorables, sin problemas éticos ni de seguridad. La mayoría de los estudios con mioblastos esqueléticos también han demostrado que contribuyen significativamente a mejorar la función cardíaca, sobre todo la sistólica, aunque tienen el inconveniente no aclarado totalmente, de inducir arritmias ventriculares malignas. Tanto en uno como en otro caso los estudios clínicos están en la fase inicial y se hace necesario nuevos estudios sobre todo randomizados. En el campo digestivo se presenta la experiencia pionera del Hospital La Paz del uso de células madre procedentes de la grasa abdominal en el tratamiento de la patología fistulosa de pacientes con enfermedad de Crohn. En Oftalmología el trasplante de limbo corneal es una práctica reconocida, usándose células del ojo contralateral cuando el daño es en un solo ojo y células de un donante cuando el daño es bilateral. Por último, en el campo neurológico se han identificado diversas zonas del cerebro de mamíferos adultos donde existen células troncales: el hipocampo, la zona subventricular, el bulbo olfatorio y la zona periependimaria de la médula espinal. Por otra parte, es posible obtener neuronas a partir de células troncales adultas procedentes de otros tejidos, como la médula ósea o el tejido adiposo, lo que supondría una fuente prácticamente inagotable de precursores neurales, bien mediante implante directo tras su selección o bien tras su cultivo in vitro. Aunque hasta la fecha la mayor parte de la experimentación es animal, se están poniendo ya en marcha ensayos clínicos de seguridad en esclerosis lateral amiotrófica

The present state of clinical regenerative medicine with adult stem cells in the cardiology, digestive, corneal and neurological fields are reviewed. From the cardiology point of view, there is clinical experience with bone marrow stem cells and peripheral blood cells and with skeletal myoblasts. At present, the adult stem cells (bone marrow hematopoietics or mesenchymal) constitute the best option for the regeneration of heart tissue, the clinical studies showing favorable results without ethical or safety problems. Most of the studies with skeletal myoblasts have also been demonstrated to significantly contribute to improve heart function, above all, the systolic one. However they have the disadvantage that has not been totally clarified that they induce malignant ventricular arrhythmias. In either case, the clinical studies are in the initial phase and new studies, above all randomized, are necessary. In the digestive field, there is the pioneer experience of the Hospital La Paz on the use of stem cells from abdominal fat in the treatment of fistulous condition of patients with Chron disease. In ophthalmology, the limbal corneal transplant is a recognized practice, using cells from the contralateral eye when the damage is in a single eye and cells from a donor when the damage is bilateral. Finally, in the neurological field, different zones of the adult mammal brain where there are stem cells have been identified: the hippocampus, subventricular zone, olfactory bulb and periependymal zone of the spinal cord. On the other hand, neurons may be obtained from adult stem cells from other tissues, such as the bone marrow or adipose tissue, which means a practically unendable source of neural precursors, either by direct implant after their selection or after their in vitro culture. However, most of the experimentation is animal up to now, clinical trails on safety in amyotrophic lateral sclerosis are now being initiated

El ácido linoleico conjugado disminuye la hipercolesterolemia pero aumenta el riesgo de litiasis biliar / Conjugated linoleic acid lowers hypercholesterolemia but increases the risk for biliary lithiasis

El término ácido linoleico conjugado (ALC) designa una serie de isómeros del ácido linoleico, presentes en la carne y productos lácteos de rumiantes, que presentan sus dos dobles enlaces en posición conjugada. El objetivo del presente trabajo fue estudiar los efectos de un isómero del ALC, el trans-10, cis-12, sobre la colesterolemia y el riesgo de litiasis biliar en un modelo animal de hipercolesterolemia inducida por dieta. Para ello se utilizaron dos grupos de hámsters alimentados con una dieta hipercolesterolemiante suplementada al 0,5% con ácido linoleico o con el isómero trans-10, cis-12 del ALC, respectivamente. Se midió diariamente su ingesta de alimento y peso corporal y, tras 6 semanas, se obtuvieron muestras de suero y bilis, y se diseccionaron y pesaron sus hígados y bazos. Se determinó la colesterolemia, el contenido hepático y esplénico de colesterol, y la concentración biliar de colesterol, fosfolípidos y sales biliares; se calculó el índice litogénico biliar y se evaluó la presencia de cálculos biliares. El ALC no modificó la ingesta energética, el peso corporal final, ni el tamaño y contenido de colesterol del bazo, pero sí produjo una disminución significativa del colesterol sérico total (-18%) a expensas de la fracción c-LDL (-66%), y también redujo significativamente el contenido hepático de colesterol libre (-26%), sin cambios en el colesterol esterificado. Además, el ALC produjo un incremento del 32% de la concentración biliar de colesterol, un aumento del 28% del índice litogénico y una mayor incidencia de litiasis biliar. Por tanto, el presente estudio demuestra que el isómero trans-10, cis-12 del ALC es hipocolesterolemiante debido, al menos en parte, a que aumenta la secreción de colesterol a bilis. En contrapartida, este efecto aumenta el riesgo de litiasis biliar (AU)

The term conjugated linoleic acid (CLA) refers to a series of linoleic acid isomers present in meat and diary products from ruminants that have their double bonds in a conjugated position. The aim of the present work was to study the effects of a CLA isomer, trans-10,cis-12, on cholesterolemia and biliary lithiasis risk in an animal model of diet-induced hypercholesterolemia. For that, two groups of hamsters were fed with a hypercholesterolemic diet supplemented with 0.5% linoleic acid or with the trans-10,cis-12 CLA isomer, respectively. Daily food intake and weight were determined and, 6 weeks later, serum and bile samples were obtained, and livers and spleens were dissected and weighted. Cholesterolemia, hepatic and splenic cholesterol content, and biliary cholesterol phosnolipid and bileacid concentrations were determined; Biliary Lithogenic Index was calculated, and presence of gallstones was assessed. CLA did not modify energetic intake or final body weight, spleen size or spleen cholesterol content, but it did significantly reduce total serum cholesterol (-18%) at the expense of c-LDL (-66%), and it also significantly reduced hepatic content of free cholesterol (-26%), without changes in esterified cholesterol. Besides, CLA produced a 32% increase in biliary cholesterol concentration, a 28% increase in Lithogenic Index, and a higher incidence of biliary lithiasis. Therefore, the present study shows that the CLA trans-10,cis-12 isomer is hypercholesterolemic since it increases, at least in part, cholesterol secretion to the bile. As a consequence, this effect increases the risk for biliary lithiasis (AU)

[P. aeruginosa bacteremias: analysis of prognostic factors. A prospective study, 1992-1998]. / Bacteriemias por P. aeruginosa: análisis de los factores pronóstico. Estudio prospectivo 1992-1998.

INTRODUCTION: P. aeruginosa causes serious infections with high mortality. OBJECTIVES: Identify the prognostic factors associated with higher mortality in P. aeruginosa bacteremias (PAB). METHODS: 211 consecutive cases of PAB were analyzed prospectively between 1992-1998. Blood cultures, isolation, and antimicrobial sensitivity were carried out according to microbiology standard methodology. The variables analyzed as prognostic factors were: sex, age, source of infection, background, main disease, initial clinical severity, foci, presence of complications, leukocyte count, type of antibiotic treatment and adaptation. Bivariate and multivariate statistical analyses were carried out by the method of logistic regression. RESULTS: Global mortality was 27.96%; factors associated with higher mortality in the bivariate study were main disease rapidly and eventually fatal, diabetes, a situation of critical initial clinical severity, lung focus, complications, neutropenia and inadequate antibiotic treatment. The logistic regression study, the critical initial clinical severity, and the presence of complications were the variables associated with worse prognosis. We did not find significant differences in the evolution among the patients who received monotherapy and those on combinations of antimicrobial drugs against pseudomonas. CONCLUSION: Higher mortality of PAB is statistically associated to the situation of critical initial clinical severity and to the presence of complications; therefore, an early diagnosis and adequate treatment to improve the morbidity and mortality are recommended.

Bacteriemias por P. aeruginosa: análisis de los factores pronóstico. Estudio prospectivo 1992-1998 / P. aeruginosa bacteremias: analysis of prognostic factors. A prospective study, 1992-1998

Introducción. P. aeruginosa causa infecciones graves con alta mortalidad. Objetivos. Identificar los factores pronóstico asociados a mayor mortalidad en bacteriemias por P. aeruginosa (BPA).Métodos. Se analizaron prospectivamente 211 casos consecutivos de BPA entre 1992-1998.Los hemocultivos, aislamiento y sensibilidad antimicrobiana fueron realizados según la metodología estándar de microbiología. Las variables analizadas como factores pronóstico fueron: sexo, edad, adquisición, antecedentes, enfermedad de base, gravedad clínica inicial, focos, presencia de complicaciones, recuento leucocitario, tipo de tratamiento antibiótico y adecuación. Se realizaron análisis estadísticos bivariantes y multivariantes por el método de la regresión logística. Resultados. La mortalidad global fue del 27,96 por ciento, encontrando como factores asociados a mayor mortalidad en el estudio bivariante, enfermedad de base rápidamente y últimamente fatal, diabetes, situación de gravedad clínica inicial crítica, foco pulmonar, complicaciones, neutropenia y tratamiento antibiótico inadecuado. El estudio de regresión logística, la gravedad clínica inicial crítica y la presencia de complicaciones fueron los factores asociados a peor pronóstico. No encontramos diferencias significativas en la evolución entre los que recibieron monoterapia y combinaciones de antimicrobianos antipseudomonas. Conclusión. La elevada tasa de mortalidad de BPA se asocia estadísticamente con la situación de gravedad clínica inicial crítica y la presencia de complicaciones, requiriendo un diagnóstico y tratamiento precoz adecuado para mejorar su morbimortalidad (AU)

[Transient atrial fibrillation induced by adenosine in a patient with atrial tachycardia]. / Fibrilación auricular transitoria inducida por adenosina en una paciente con taquicardia auricular.

The administration of adenosine during atrial tachycardia usually terminates the arrhythmia or induces AV block and makes the diagnosis clear. We present a patient with atrial tachycardia in which the administration of adenosine induced a transient atrial fibrillation (AF). A continuous transition between both arrhythmias was observed and the original tachycardia persisted after the termination of the AF. This proarrhythmic effect may be due to the adenosine-mediated shortening of the atrial refractory periods, which produces a decreased wavelength of the reentry circuits and the potential coexistence of several wave-fronts in the atria, favoring the development of AF. The recognition of this uncommon effect is important, since the repeated administration of increasing doses of adenosine may induce sustained AF.

Fibrilación auricular transitoria inducida por adenosina en una paciente con taquicardia auricular / Adenosine-induced transient atrial fibrillation in a patient with atrial tachycardia

La administración de adenosina durante taquicardia auricular suele producir la terminación de la misma o aumentar el grado de bloqueo AV facilitando su diagnóstico. Presentamos un caso de inducción de fibrilación auricular (FA) transitoria por adenosina en una paciente con taquicardia auricular. La transición entre ambos ritmos fue contínua, persistiendo la taquicardia original al finalizar la FA. Este efecto proarrítmico se cree debido al acortamiento de los peridodos refractarios auriculares inducido por la adenosina, disminuyendo la longitud de onda de los circuitos de reentrada y facilitando de este modo la coexistencia simultánea de varios frentes de activación en las aurículas como ocurre en la FA.Aunque es un fenómeno poco común, su reconocimiento es importante para evitar la administración repetida de dosis crecientes de adenosina, que podría llevar a la inducción de FA sostenida (AU)

Papel de las proteínas desacoplantes en la obesidad / Role of uncoupling proteins in obesity

El descubrimiento de una proteína de la membrana mitocondrial interna de adipocitos marrones, la UCP1, supuso un importante avance en el conocimiento del proceso termogénico, así como del funcionamiento del tejido adiposo marrón. Esta proteína es sólo importante en neonatos y animales pequeños, no obstante el posterior hallazgo de proteínas análogas a la UCP1 (UCP2, ampliamente distribuida, y UCP3, presente principalmente en músculo) con un funcionamiento similar y presentes también en tejido humano, creó nuevas perspectivas y objetivos científicos. Estas proteínas desacoplan la cadena respiratoria de la fosforilación oxidativa, disipando así energía en forma de calor sin que se produzca ATP, mediante un mecanismo aún debatido. De los estudios de regulación realizados trasciende que su actividad se ve modificada ante distintos estímulos fisiológicos y nutricionales, observándose una mayor actividad de las mismas en situaciones en las que se requiere un aumento del gasto energético. Los estudios realizados en humanos parecen corroborar los resultados obtenidos en la experimentación con animales, por lo que podría plantearse la actuación sobre la actividad o la cantidad de estas proteínas en humanos como medio para combatir el sobrepeso y la obesidad. Sin embargo, existe aún una evidente necesidad de completar y mejorar la información existente acerca de la importancia de estas proteínas transportadoras de protones en humanos. (AU)

[Role of uncoupling proteins in obesity]. / Papel de las proteínas desacoplantes en la obesidad.

The discovery of a protein of the internal mitochondrial membrane of the brown adipocytes, the UCP1, marked an important advance in the understanding of the thermogenic process, as well as of the working of the brown adipose tissue. This protein is only of importance in the newly born and small animals, however the later discovery of proteins that were analogues of UCP1 (UCP2, widely distributed, and UCP3, mainly present in the muscle) with a similar functioning and also present in human tissue, created new perspectives and scientific goals. These proteins uncouple the respiratory chain of the oxidative phosphorylation, thus dissipating energy in the form of heat without producing ATP, by means of a mechanism that is still the subject of debate. From the studies of regulation that have been made, it emerges that their activity is modified when facing different physiological and nutritional stimuli, with greater activity observed in situations where an increase of energy expenditure is required. The studies carried on humans seem to corroborate the results obtained in experiments on animals, and action can thus be proposed on the activity, or the quantity, of these proteins in humans, as a means for fighting overweightedness and obesity. However, there is still an evident need to complete and improve the existing information on the importance of these proton transporting proteins in humans.

[Ventricular arrhythmias induced by appropriate antibradycardia pacing in patients with implantable defibrillators]. / Inducción de arritmias ventriculares por estimulación antibradicardia apropiada en pacientes portadores de desfibrilador automático.

INTRODUCTION AND OBJECTIVES: The induction of ventricular arrhythmias by appropriate antibradycardia ventricular pacing in patients with implantable cardioverter defibrillators has been reported in only a few cases. The aim of this study was to assess the incidence, characteristics and management of these episodes. METHODS: The follow-up records of 180 patients with implantable cardioverter defibrillators with intracardiac electrogram storage were reviewed. Pacing induced episodes were defined as those occurring immediately after an appropriate paced stimulus in a patient with sporadic paced beats. We assessed the number and type of episodes, mode of onset, therapy administered and the efficacy of different prevention measures. RESULTS: Pacing induced episodes were found in 9 patients (5%). Seven received device administered therapy which was effective in all cases. One to 95 episodes were observed per patient, of which 138 were monomorphic ventricular tachycardias and 20 polymorphic ventricular tachycardia/ventricular fibrillation episodes. All were induced by a paced ventricular beat after a post-extrasystolic pause or after long RR intervals during atrial fibrillation. Pacing induced arrhythmias were prevented by changing the pacing rate or hysteresis in 3 out of 6 patients and by decreasing the stimulus energy in 3 out of 3. Antibradycardia pacing function was disabled in 4 patients. CONCLUSIONS: Ventricular arrhythmias induced by appropriate antibradycardia ventricular pacing are relatively common in patients with implantable cardioverter defibrillators. Effective prevention can be achieved in most cases by changing the pacing rate or the pacing stimulus energy, however in selected cases the antibradycardia function may be disabled.

Differential effects of diets that provide different lipid sources on hepatic lipogenic activities in rats under ad libitum or restricted feeding.

This work was designed to study the effect of different lipid sources on hepatic lipogenic enzyme activity in rats fed ad libitum or energy-controlled diets. Male Wistar rats were fed diets containing 40% of energy as fat (olive oil, sunflower oil, palm oil, or beef tallow) for 4 wk. In experiment 1 rats had free access to food, and in experiment 2 rats were fed a controlled amount of food. In both experiments, rats fed the olive oil diets had higher activities of glucose-6-phosphate dehydrogenase, malic enzyme, fatty acid synthase, and acetyl-CoA carboxylase (P < 0.05) than rats fed the other fats. It is unlikely that this effect could be attributed to the stimulation by insulin or triiodothyronine because serum values did not differ among the groups. Enzymatic activities were positively and significantly correlated with liver triacylglycerol content, but not with serum triacylglycerol levels. No interaction between lipid source and feeding protocol was found. Oleic acid and components in olive oil other than fatty acids, such as phytosterols, may account for the effects of dietary fat on lipogenic enzyme activity.

[Concurrent long QT and Brugada syndrome in a single patient]. / Presentación de síndrome de Brugada e intervalo QT largo en un mismo paciente.

We present a 61-year-old patient with previous cardiac arrest and frequent syncopal spells. ECG showed a typical Brugada pattern and a QTc interval of 425 ms. During programmed ventricular stimulation a self-limited syncopal polymorphic ventricular tachycardia was induced. On diagnosis of the Brugada syndrome an implantable cardioverter defibrillator was implanted. Two days later two episodes of polimorphic ventricular arrhythmia were converted by the device. The ECG at this time showed a prolonged QTc of 500 ms in addition to a typical Brugada pattern. Atenolol was started and after a 36-month follow-up the patient has remained asymptomatic without arrhythmic events. In conclusion, this patient has the Brugada syndrome and also fulfills the clinical and ECG characteristics of the Long QT syndrome. These findings suggest a genetic link between the two syndromes.

Comparative study of treatment with penicillin, ceftriaxone, trovafloxacin, quinupristin-dalfopristin and vancomycin in experimental endocarditis due to penicillin- and ceftriaxone-resistant Streptococcus pneumoniae.

The efficacy of different antibiotics was compared in an experimental model of aortic valve endocarditis in rabbits, using a serotype 19 strain of Streptococcus pneumoniae resistant to penicillin (MIC 12 mg/L) and ceftriaxone (MIC 12 mg/L). The results were compared with those of a control group, which received no treatment. One hundred and nineteen animals were treated with one of the following antibiotic regimens: im procaine penicillin G at a dosage of 300,000 U/kg weight/12 h (16 animals); iv trovafloxacin, 13.3 mg/kg/12 h (31 animals); iv ceftriaxone, 75 mg/kg/24 h (21 animals); iv vancomycin, 20 mg/kg/12 h (15 animals) and im quinupristin-dalfopristin, 30 mg/kg/8 h (20 animals). All the antibiotics used in this study proved to be efficient in reducing numbers of S. pneumoniae and in increasing the percentage of aortic vegetations that were rendered sterile compared with the control group. Penicillin at the dosage used in our study was capable of achieving serum concentrations two or three times greater than the MIC, thus demonstrating its effectiveness as an antibiotic for this endocarditis model. No significant difference was observed between the effects of vancomycin, quinupristin-dalfopristin and penicillin. Vancomycin proved to be more efficient than trovofloxacin in reducing the bacterial load and increasing the numbers sterilized. There was also a tendency for this antibiotic to be more effective than ceftriaxone in reducing the bacterial load of the vegetations. There was a statistically significant correlation between the weight of the vegetations and their bacterial load. In the light of these results, vancomycin and quinupristin-dalfopristin may be considered suitable alternatives to penicillin for the treatment of penicillin-resistant S. pneumoniae endocarditis.

Effects of the whole seed and a protein isolate of faba bean (Vicia faba) on the cholesterol metabolism of hypercholesterolaemic rats.

The aim of the present work was to analyse the hypocholesterolaemic efficiency of a Vicia faba-protein isolate in relation to the intact legume. In addition, the mechanisms underlying the effects of this isolate were investigated. Hypercholesterolaemic rats were divided into three groups and fed high-fat diets rich in cholesterol-containing casein, whole seeds of Vicia faba or the protein isolate of faba beans as protein source, for 2 weeks ad libitum. The protein isolate was prepared by isoelectric precipitation and spray dried. Analyses of serum, liver and faeces, as well as of the activity of hepatic 3-hydroxy-3-methylglutaryl (HMG)-CoA reductase, were assessed by enzymatic methods. The rats fed on Vicia faba diets showed significantly lower body weights and energy intakes than rats fed on casein diets. The whole-seed diet induced a significant reduction in plasma triacylglycerol. Feeding rats on diets containing faba bean seeds, or the protein isolate, induced a significant decrease in plasma (LDL+VLDL)-cholesterol but not in HDL-cholesterol. Hepatic cholesterol and triacylglycerol were also reduced. The hypocholesterolaemic effects of Vicia faba were not the result of a reduction in cholesterol synthesis as assessed from HMG-CoA reductase activity, but the result of an increase in steroid faecal excretion. The faba bean-protein isolate obtained under our experimental conditions was useful in improving the metabolic alterations induced by feeding with a hypercholesterolaemic diet compared with casein. The effectiveness of the whole seeds was higher than that of the protein isolate.