Ana Gómez - Academia.edu (original) (raw)
Papers by Ana Gómez
Journal of Physiology-london, 2001
1. Aldosterone, a major ionic homeostasis regulator, might also regulate cardiac ion currents. Us... more 1. Aldosterone, a major ionic homeostasis regulator, might also regulate cardiac ion currents. Using the whole-cell patch-clamp technique, we investigated whether aldosterone affects the 4-aminopyridine-sensitive transient outward K+ current (I(to1)). 2. Exposure to 100 nM aldosterone for 48 h at 37 degrees C produced a 1.6-fold decrease in the I(to1) density compared to control myocytes incubated without aldosterone. Neither the time- nor voltage-dependent properties of the current were significantly altered after aldosterone treatment. RU28318 (1 microM), a specific mineralocorticoid receptor antagonist, prevented the aldosterone-induced decrease in I(to1) density. 3. When myocytes were incubated for 24 h with aldosterone, concentrations up to 1 microM did not change I(to1) density, whereas L-type Ca(2+) current (I(Ca,L)) density increased. After 48 h, aldosterone caused a further increase in I(Ca,L). The delay in the I(to1) response to aldosterone might indicate that it occurs secondary to an increase in I(Ca,L). 4. After 24 h of aldosterone pretreatment, further co-incubation for 24 h either with an I(Ca,L) antagonist (100 nM nifedipine) or with a permeant Ca(2+) chelator (10 microM BAPTA-AM) prevented a decrease in I(to1) density. 5. After 48 h of aldosterone treatment, we observed a 2.5-fold increase in the occurrence of spontaneous Ca(2+) sparks, which was blunted by co-treatment with nifedipine. 6. We conclude that aldosterone decreases I(to1) density. We suggest that this decrease is secondary to the modulation of intracellular Ca(2+) signalling, which probably arises from the aldosterone-induced increase in I(Ca,L). These results provide new insights into how cardiac ionic currents are modulated by hormones.
Journal of Molecular and Cellular Cardiology, 1999
C. D, A. A, A. M. G G. V. Frequency-dependent Increase in Cardiac Ca 2+... more C. D, A. A, A. M. G G. V. Frequency-dependent Increase in Cardiac Ca 2+ Current is due to Reduced Ca 2+ Release by the Sarcoplasmic Reticulum. Journal of Molecular and Cellular Cardiology (1999) 31, 1783-1793. "Ca 2+ -current facilitation" describes several features of increase in current amplitude often associated with a reduction in inactivation rate. The aim of this study was to investigate the mechanism of frequency-dependent increase in L-type Ca 2+ current, I Ca taking advantage of recent knowledge on the control of Ca 2+ current inactivation in cardiac cells. The frequency-dependent increase in I Ca was studied in adult rat ventricular myocytes using the whole-cell patch-clamp technique. I Ca was elicited by a train of 200-ms depolarizing pulses to +20 mV applied at various frequencies (0.2 up to 1.3 Hz). The increase in frequency induced a ratedependent enhancement of I Ca , or facilitation phenomena. In most cells, that showed two inactivation phases of I Ca , facilitation was mainly related to slowing of the fast I Ca inactivation phase that occurred besides increase in peak I Ca amplitude. Both the decrease and slowing of the fast component of inactivation phase were attenuated on -adrenergic-stimulated current. Frequency-dependent I Ca facilitation paralleled a reduction in Ca 2+ transient measured with fluo-3. After blocking sarcoplasmic reticulum-Ca 2+ release by thapsigargin, the fast I Ca inactivation phase was reduced and facilitation was eliminated. Facilitation could not then be restored by 1 isoprenaline. Thus in rat ventricular myocytes, frequency-dependent facilitation of I Ca reflects a reduced Ca 2+ -dependent inactivation consecutive, in most part, to reduced Ca 2+ load and Ca 2+ release by the sarcoplasmic reticulum rather than being an intrinsic characteristic of the L-type Ca 2+ channel.
Journal of Thoracic and Cardiovascular Surgery, 2004
donors who died out of hospital Bipulmonary transplants with lungs obtained from two non-heart-be... more donors who died out of hospital Bipulmonary transplants with lungs obtained from two non-heart-beating Figure 2. Preoperative CT scan. The metallic wall-stent prosthesis compresses the anterior wall of the gastric tube against the "pars membranacea" of the right main bronchus.
The paper studies the effects of Familias en Acción, a conditional cash transfer programme implem... more The paper studies the effects of Familias en Acción, a conditional cash transfer programme implemented in rural areas in Colombia in 2002, on school enrolment and child labour. Using a quasi-experimental approach, our methodology makes use of an interesting feature of the data, which allows us to identify anticipation effects. Our results show that the programme increased school participation of 14 to 17 year old children quite substantially, by between 5 and 7 percentage points, and had lower, but non-negligible effects on enrolment of younger children of between around 1.5 and 2.5 percentage points. In terms of work, the effects are generally largest for younger children whose participation in domestic work decreased by around 10 to 12 percentage points after the programme but whose participation in income-generating work remained largely unaffected by the programme. We also find evidence of school and work time not being fully substitutable, suggesting that some, but not all, of the increased time at school may be drawn from children's leisure time.
Drug resistance in Mycobacterium tuberculosis complex strains is solely due to chromosomal mutati... more Drug resistance in Mycobacterium tuberculosis complex strains is solely due to chromosomal mutations that could affect bacterial virulence. Molecular epidemiology studies have shown that resistant strains are less likely to be clustered than susceptible strains. However, a few multidrug-resistant (MDR) M. tuberculosis complex strains have been described as causing outbreaks, suggesting that they have restored virulence or increased transmission. One of the biggest MDR tuberculosis outbreaks documented to date was caused by the B strain of M. bovis. Restriction fragment length polymorphism fingerprinting revealed that the B strain contains two copies of IS6110. Here, we mapped and sequenced the regions flanking the two copies of IS6110 in the B strain. Ligation-mediated PCR showed that one of these IS6110 copies is located within the promoter region of phoP, a transcriptional regulator that is essential for M. tuberculosis virulence. We used PCR to screen 219 MDR M. tuberculosis complex strains (90.4% of all MDR isolates) isolated in Spain between 1998 and 2002 and found that the B strain was the only strain that contained a copy of IS6110 in the phoP promoter. To determine whether IS6110 affects phoP promoter activity in the B strain, we individually cloned the phoP gene and its promoter region (including IS6110 from the B strain and the equivalent region from M. tuberculosis without IS6110 as a control) into a mycobacterial replicative plasmid and transformed M. smegmatis with the resulting plasmid. Primer extension analysis showed that phoP transcription was strongly upregulated when the promoter region contained IS6110, as in the case of the B strain.
El qué y el para qué de la memoria humana Posiblemente lo más importante para cualquier ser human... more El qué y el para qué de la memoria humana Posiblemente lo más importante para cualquier ser humano es su capacidad para almacenar experiencias y poder beneficiarse de dichas experiencias en su actuación futura. El engranaje y los mecanismos que rigen el funcionamiento de este colosal proceso psicológico funcionan con tal grado de per-fección que la persona sana apenas es consciente de que todas sus acciones y todas sus comunicaciones verbales dependen del correcto funcionamiento de su memoria. Sin embargo, cuando la memoria falla, ya sea de manera circunstancial y momentánea, ya sea de manera permanente, el individuo se da cuenta, en medio de la frustración, de su importancia. ¿Quién no ha pasado por alguna situación social embarazosa cuando, a pesar de intentarlo con ahínco, no puede recordar el nombre de una persona a la que se está seguro de conocer? No menos frustrante es cuando creemos que hemos guardado algún objeto o documento en un lugar y comprobamos que no está donde creíamos La memoria es un proceso psicológico que sirve para almacenar información codificada. Dicha información puede ser recuperada, unas veces de forma voluntaria y consciente y otras de manera involuntaria. En el estudio de la memoria, unos investigadores han destacado sus componentes estructurales mientras otros se han centrado en los procesos de memoria. En este Número Especial se recogen trabajos sobre la memoria icónica, la memoria de trabajo y memoria a largo plazo perceptiva y semántica. Varios trabajos se dedican al estudio del priming perceptivo y semántico para palabras, dibujos y objetos 3-D familiares y no familiares. Los resultados parece que están más en consonancia con la postura de los sistemas de memoria que con la teoría procesual.
Journal of Physiology-london, 2001
1. Aldosterone, a major ionic homeostasis regulator, might also regulate cardiac ion currents. Us... more 1. Aldosterone, a major ionic homeostasis regulator, might also regulate cardiac ion currents. Using the whole-cell patch-clamp technique, we investigated whether aldosterone affects the 4-aminopyridine-sensitive transient outward K+ current (I(to1)). 2. Exposure to 100 nM aldosterone for 48 h at 37 degrees C produced a 1.6-fold decrease in the I(to1) density compared to control myocytes incubated without aldosterone. Neither the time- nor voltage-dependent properties of the current were significantly altered after aldosterone treatment. RU28318 (1 microM), a specific mineralocorticoid receptor antagonist, prevented the aldosterone-induced decrease in I(to1) density. 3. When myocytes were incubated for 24 h with aldosterone, concentrations up to 1 microM did not change I(to1) density, whereas L-type Ca(2+) current (I(Ca,L)) density increased. After 48 h, aldosterone caused a further increase in I(Ca,L). The delay in the I(to1) response to aldosterone might indicate that it occurs secondary to an increase in I(Ca,L). 4. After 24 h of aldosterone pretreatment, further co-incubation for 24 h either with an I(Ca,L) antagonist (100 nM nifedipine) or with a permeant Ca(2+) chelator (10 microM BAPTA-AM) prevented a decrease in I(to1) density. 5. After 48 h of aldosterone treatment, we observed a 2.5-fold increase in the occurrence of spontaneous Ca(2+) sparks, which was blunted by co-treatment with nifedipine. 6. We conclude that aldosterone decreases I(to1) density. We suggest that this decrease is secondary to the modulation of intracellular Ca(2+) signalling, which probably arises from the aldosterone-induced increase in I(Ca,L). These results provide new insights into how cardiac ionic currents are modulated by hormones.
Journal of Molecular and Cellular Cardiology, 1999
C. D, A. A, A. M. G G. V. Frequency-dependent Increase in Cardiac Ca 2+... more C. D, A. A, A. M. G G. V. Frequency-dependent Increase in Cardiac Ca 2+ Current is due to Reduced Ca 2+ Release by the Sarcoplasmic Reticulum. Journal of Molecular and Cellular Cardiology (1999) 31, 1783-1793. "Ca 2+ -current facilitation" describes several features of increase in current amplitude often associated with a reduction in inactivation rate. The aim of this study was to investigate the mechanism of frequency-dependent increase in L-type Ca 2+ current, I Ca taking advantage of recent knowledge on the control of Ca 2+ current inactivation in cardiac cells. The frequency-dependent increase in I Ca was studied in adult rat ventricular myocytes using the whole-cell patch-clamp technique. I Ca was elicited by a train of 200-ms depolarizing pulses to +20 mV applied at various frequencies (0.2 up to 1.3 Hz). The increase in frequency induced a ratedependent enhancement of I Ca , or facilitation phenomena. In most cells, that showed two inactivation phases of I Ca , facilitation was mainly related to slowing of the fast I Ca inactivation phase that occurred besides increase in peak I Ca amplitude. Both the decrease and slowing of the fast component of inactivation phase were attenuated on -adrenergic-stimulated current. Frequency-dependent I Ca facilitation paralleled a reduction in Ca 2+ transient measured with fluo-3. After blocking sarcoplasmic reticulum-Ca 2+ release by thapsigargin, the fast I Ca inactivation phase was reduced and facilitation was eliminated. Facilitation could not then be restored by 1 isoprenaline. Thus in rat ventricular myocytes, frequency-dependent facilitation of I Ca reflects a reduced Ca 2+ -dependent inactivation consecutive, in most part, to reduced Ca 2+ load and Ca 2+ release by the sarcoplasmic reticulum rather than being an intrinsic characteristic of the L-type Ca 2+ channel.
Journal of Thoracic and Cardiovascular Surgery, 2004
donors who died out of hospital Bipulmonary transplants with lungs obtained from two non-heart-be... more donors who died out of hospital Bipulmonary transplants with lungs obtained from two non-heart-beating Figure 2. Preoperative CT scan. The metallic wall-stent prosthesis compresses the anterior wall of the gastric tube against the "pars membranacea" of the right main bronchus.
The paper studies the effects of Familias en Acción, a conditional cash transfer programme implem... more The paper studies the effects of Familias en Acción, a conditional cash transfer programme implemented in rural areas in Colombia in 2002, on school enrolment and child labour. Using a quasi-experimental approach, our methodology makes use of an interesting feature of the data, which allows us to identify anticipation effects. Our results show that the programme increased school participation of 14 to 17 year old children quite substantially, by between 5 and 7 percentage points, and had lower, but non-negligible effects on enrolment of younger children of between around 1.5 and 2.5 percentage points. In terms of work, the effects are generally largest for younger children whose participation in domestic work decreased by around 10 to 12 percentage points after the programme but whose participation in income-generating work remained largely unaffected by the programme. We also find evidence of school and work time not being fully substitutable, suggesting that some, but not all, of the increased time at school may be drawn from children's leisure time.
Drug resistance in Mycobacterium tuberculosis complex strains is solely due to chromosomal mutati... more Drug resistance in Mycobacterium tuberculosis complex strains is solely due to chromosomal mutations that could affect bacterial virulence. Molecular epidemiology studies have shown that resistant strains are less likely to be clustered than susceptible strains. However, a few multidrug-resistant (MDR) M. tuberculosis complex strains have been described as causing outbreaks, suggesting that they have restored virulence or increased transmission. One of the biggest MDR tuberculosis outbreaks documented to date was caused by the B strain of M. bovis. Restriction fragment length polymorphism fingerprinting revealed that the B strain contains two copies of IS6110. Here, we mapped and sequenced the regions flanking the two copies of IS6110 in the B strain. Ligation-mediated PCR showed that one of these IS6110 copies is located within the promoter region of phoP, a transcriptional regulator that is essential for M. tuberculosis virulence. We used PCR to screen 219 MDR M. tuberculosis complex strains (90.4% of all MDR isolates) isolated in Spain between 1998 and 2002 and found that the B strain was the only strain that contained a copy of IS6110 in the phoP promoter. To determine whether IS6110 affects phoP promoter activity in the B strain, we individually cloned the phoP gene and its promoter region (including IS6110 from the B strain and the equivalent region from M. tuberculosis without IS6110 as a control) into a mycobacterial replicative plasmid and transformed M. smegmatis with the resulting plasmid. Primer extension analysis showed that phoP transcription was strongly upregulated when the promoter region contained IS6110, as in the case of the B strain.
El qué y el para qué de la memoria humana Posiblemente lo más importante para cualquier ser human... more El qué y el para qué de la memoria humana Posiblemente lo más importante para cualquier ser humano es su capacidad para almacenar experiencias y poder beneficiarse de dichas experiencias en su actuación futura. El engranaje y los mecanismos que rigen el funcionamiento de este colosal proceso psicológico funcionan con tal grado de per-fección que la persona sana apenas es consciente de que todas sus acciones y todas sus comunicaciones verbales dependen del correcto funcionamiento de su memoria. Sin embargo, cuando la memoria falla, ya sea de manera circunstancial y momentánea, ya sea de manera permanente, el individuo se da cuenta, en medio de la frustración, de su importancia. ¿Quién no ha pasado por alguna situación social embarazosa cuando, a pesar de intentarlo con ahínco, no puede recordar el nombre de una persona a la que se está seguro de conocer? No menos frustrante es cuando creemos que hemos guardado algún objeto o documento en un lugar y comprobamos que no está donde creíamos La memoria es un proceso psicológico que sirve para almacenar información codificada. Dicha información puede ser recuperada, unas veces de forma voluntaria y consciente y otras de manera involuntaria. En el estudio de la memoria, unos investigadores han destacado sus componentes estructurales mientras otros se han centrado en los procesos de memoria. En este Número Especial se recogen trabajos sobre la memoria icónica, la memoria de trabajo y memoria a largo plazo perceptiva y semántica. Varios trabajos se dedican al estudio del priming perceptivo y semántico para palabras, dibujos y objetos 3-D familiares y no familiares. Los resultados parece que están más en consonancia con la postura de los sistemas de memoria que con la teoría procesual.