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Medicina Intensiva 01/2013; · 1.07 Impact Factor
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ABSTRACT: Peripheral blood is an easily accessed source for stem cell production; however, the number of cells produced is relatively low. We hypothesized that ischemic preconditioning may serve as a safe method to increase the number of CD34+ cells that can be harvested and cultured in a short period. This study was conducted to test this hypothesis by examining the safety and efficacy of brief, transient ischemia of the lower limbs to augment the number of cells that can be produced from blood of healthy volunteers. Following induction of ischemia, blood samples were withdrawn at baseline, 30 min, 12 h and 24 h. The number of progenitor cells was determined by flow cytometry after the harvested cells were cultured for 5 days. We also analyzed the blood samples to determine IL-8 and VEGF concentrations. No serious adverse events were observed. The total number of cells increased from 0.46 ± 0.1 × 10^6 cells/ml in the pretreatment blood samples to 0.7 ± 0.1 × 10^6 cells/ml in blood taken 12 h after the conclusion of transient ischemia, p = 0.0029. The number of CD34+ cells increased from 4.23 ± 0.8 × 10^4 cells/ml in the pretreatment samples to 7.17 ± 1.34 × 10^4 cells/ml in blood taken 12 h after ischemia, p = 0.0001. The harvested stem cells maintained their ability to construct tubular structures. The augmentation in the number of CD34+ cells was positively correlated with the increase of IL-8, but not with VEGF concentrations. Ischemic preconditioning is a safe and effective technique to increase the availability of stem cells for therapeutic purposes.
01/2012: pages 303-308; , ISBN: 978-1-4471-2905-9
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ABSTRACT: Physical exercise is often terminated not due to muscle fatigue but because of inadequate neural drive in the serotonergic system. Modifications in activity levels of the serotonergic system, induced by variations in the availability of L-tryptophan (a serotonin precursor) may alter neural drive. We examined the effect of L-tryptophan supplementation on physical performance by combining aerobic work with brief periods of supramaximal intensity that closely mimics the activity typical of team sports. Twenty healthy young sportsmen (mean age 21.2 +/- 0.7 years) performed a submaximal exercise on a cycle ergometer, with a workload corresponding to 50% of their respective VO(2) max for 10 min, followed by a maximal intensity exercise for 30 s. This sequence was repeated three times and, after the fourth series, each participant continued to exercise at the highest speed that he could sustain for 20 min. This protocol was performed twice: once with and finally without supplementation of L-tryptophan, in random order and double-blind. Peak power output, average anaerobic power output, and power output during the last 20 min of the trial were higher on the trials performed with L-tryptophan supplementation than on those performed with placebo. The distance covered during the last 20 min of the trial was 11,959 +/- 1,753 m on placebo and 12,526 +/- 1,617 m on L-tryptophan (p < .05). In conclusion, in some types of exercises, modification of the serotonergic system may improve the physical performance.
The International journal of neuroscience 05/2010; 120(5):319-27. · 0.86 Impact Factor
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Minerva cardioangiologica 03/2009; 57(1):137-8.
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ABSTRACT: The difference between genders has generated increasing interest in recent years. It is well known that women and men show differences in their respiratory system: different red blood cell counts, haemoglobin and 2,3-diphosphoglycerate plasma concentrations. Recently, further differences have been found in the ventilatory response to hypoxia and exercise and the evolution of some respiratory illnesses. In this study it was found that during rest at sea level, the haemoglobin oxygen saturation, as measured by pulse oxymetry, is slightly higher in women than in men (98.6 (SD 1.1)% versus 97.9 (SD 0.9)%; p = 0.001). These findings are consistent with other studies, which found gender differences in the transcutaneous or tissue PaO(2). The difference in oxygen saturation is not related to differences in ventilation. The disparity is modest and does not seem to produce great differences in the oxygen content of arterial blood, but combined with the different affinity of haemoglobin for oxygen or different metabolic rate, may play a role in the course of elite competition sports, high altitude ascents or the evaluation of critically ill patients. Further studies are needed to establish the degree, extent and clinical importance of these differences in the saturation of haemoglobin.
British journal of sports medicine 08/2008; 42(7):620-1. · 2.55 Impact Factor
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J A Rotela Samaniego,
E Castells,
N Manito,
J Roca,
J Toscano,
J M Calbet,
E Saura,
C Fontanillas,
M Benito,
J Granados,
A Miralles,
J M Rabasa,
D Ortiz,
D Toral,
C Rullan, J L Ventura,
E Esplugas
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ABSTRACT: Heart transplantation (HT) due to valvular cardiomyopathy is rare, namely, about 3% of cases in the Registry of the International Society for Heart and Lung Transplantation (ISHLT). Usually, these patients present some risk factors such as previous valvular operations and pulmonary hypertension. Since there are few studies in the literature, we retrospectively analyzed our early and long-term results.
We studied our experience in 22 HT cases for valvular cardiomyopathy (9.3% of our total experience), namely, 12 men and 10 women, of overall mean age of 52.6 +/- 10 years. Five patients had mitral; 8, aortic; and 1, tricuspid valve disease; 7 had double valve disease and 1, triple valve disease. Nineteen patients (87%) had been operated previously between 1 and 4 times. The mean ejection fraction was 23% +/- 7.3% and the mean New York Heart Association (NYHA) functional class was 3.7. Fifty-three percent of the patients had pulmonary hypertension. Two patients were operated as an emergency "O." We used the standard HT technique.
Four patients (18%) were reoperated due to hemorrhage. The hospital mortality was 2 cases (9%). Another patients (9%) died on follow-up due to cardiac allograft vasculopathy. All surviving patients have been followed to the end of 2006. The mean follow-up has been 72 +/- 53 months. They are functional class I or II.
HT for this indication was more frequent in our experience than in the Registry of the ISHLT. The immediate and long-term results were good, with an 82% mean survival at 6 years. HT can be a good treatment for patients with valvular cardiomyopathy and bad ventricular function and/or multiple valvular reoperations.
Transplantation Proceedings 10/2007; 39(7):2355-6. · 1.00 Impact Factor
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ABSTRACT: It was believed that amiodarone-related adverse respiratory effects were found only when receiving amiodarone on a long-term basis, but several reports seem to contradict this hypothesis. The aim of this study was to evaluate, in an intensive care unit (ICU), the possibility of acute respiratory toxicity induced by short-term amiodarone administration following cardiac surgery.
We conducted a prospective clinical trial of 111 consecutive patients admitted to our ICU after cardiac surgery (basically, coronary artery bypass graft and/or valve surgery) and who received short-term prophylactic amiodarone treatment if they were considered at high risk of developing atrial fibrillation. We administered 900 mg/day intravenously for the first 2 days and 600 mg/day on the following days of the ICU stay. The oxygenation index (PaO2/FiO2 ratio) was evaluated at admission, and then 24 and 48 h postsurgery.
One-hundred and two patients were included in the study (9 were excluded for bradycardia), and 25 received amiodarone treatment. The Parsonnet and APACHE II scores differed slightly between the treated and nontreated groups. There were no significant differences between the treated and nontreated groups with respect to left atrial pressure, the number of packed red cells transfused or the oxygenation index at admission and 24 and 48 h postsurgery.
The short-term administration of amiodarone under the conditions of the present study does not seem to affect respiratory function.
The Journal of cardiovascular surgery 09/2007; 48(4):509-12. · 1.56 Impact Factor
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ABSTRACT: A global physical evaluation was performed in 21 males with spinal cord injury (SCI), at the beginning and at three and six months of omega-3 fatty acid (FA) supplementation. A significant increase in the proportion of eicosapentaenoic acid and docosahexanoic acid in plasma was observed in response to the supplementation (p<0.05). After six months of FA supplementation, strength endurance time increased from 127.7+/-19.0 s to 215.2+/-45.6 s in the right arm, and from 139+/-27.6 s to 237.7+/-48.7 s, in the left arm. The time to perform 20 repetitions of 70% maximum workload showed a reduction of 41% between the first and the third test. The time taken to cover a 90 meter long track, with a 6% slope, was reduced from 66.9+/-8.0 s to 59.3+/-6.7 s, at the end of the study (p<0.05). In conclusion, omega-3 FA supplementation could contribute to improve the functional capabilities in SCI subjects.
Journal of physiology and biochemistry 01/2007; 62(4):271-9. · 1.71 Impact Factor
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ABSTRACT: Atrial fibrillation (AF) is common after cardiac surgery, but prophylaxis for patients especially prone to developing this arrhythmia has not been studied to date. We investigated amiodarone as prophylaxis for AF in selected patients after open-heart surgery.
In the first stage we studied a group of 204 consecutive cardiac surgery patients and devised a formula from some of the known risk factors of AF for each sex to serve as a predictor model. In this first group we were able to quantify the probability of developing this arrhythmia. In the second stage we applied this formula to a group of 231 consecutive cardiac surgery patients and then selectively treated the high-risk patients for AF: 25 men (16.1%) and 29 women (53.7%). In the first 24 h of treatment with amiodarone, 22 patients (10 men and 12 women) were excluded from the study due to sinus bradycardia. Therapy consisted of amiodarone 900 mg intravenously every 24 h for the first 2 postoperative days, followed by 600 mg intravenously every 24 h until discharge from the Intensive Care Unit.
Expected AF in males fell from 34.4% (52/151) in the observation group to 11% (17/155) in the treated group, and in females from 50.9% in the observation group (27/53) to 9.3% (5/54) in the treated group (P<0.001).
Patient-selective prophylaxis of AF with amiodarone can be a highly effective measure.
Minerva chirurgica 11/2006; 61(5):403-8. · 0.77 Impact Factor
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ABSTRACT: Creatine is an ergogenic aid used in individual and team sports. The aim of this study is to analyze the effect of monohydrate creatine supplementation on physical performance during 6 consecutive maximal speed 60 meter races, and the changes induced in some characteristic biochemical and ventilatory parameters. The study was carried out on nineteen healthy and physically active male volunteers, and randomly distributed into two groups: Group C received a supplement of creatine monohydrate (20 g/day for 5 days) and group P received placebo. Tests were performed before and after supplementation. No significant changes were observed in weight or body water measured by bioimpedance or the sum of 7 skinfold or performance during the 60 meter races. Group C showed a statistically significant increase in plasma creatinine from 69.8 +/- 12.4 to 89.3 +/- 12.4 micromol x L(-1) (p<0.05). In group C in the second control day (after creatine supplementation), expiratory volume V(E), O2 uptake and CO2 production were lower after 2 minutes of active recovery period. These results indicate that creatine monohydrate supplementation does not appear to improve the performance in 6 consecutive 60 meter repeated races but may modify ventilatory dynamics during the recovery after maximal effort.
Journal of physiology and biochemistry 12/2004; 60(4):265-71. · 1.71 Impact Factor
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Medicine & Science in Sports & Exercise 04/2003; 35(5):S115. · 4.43 Impact Factor
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Proceedings of the 7th Annual Congress of the European College of Sport Science. 01/2002; I:p. 83.
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Proceedings of the 7 th Annual Congress of the European College of Sport ScienceProceedings of the 7 th Annual Congress of the European College of Sport Science, Athens, Greece; 01/2002
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H Casas,
B Murtra,
M Casas,
J Ibáñez, J L Ventura,
A Ricart,
F Rodríguez,
G Viscor,
L Palacios,
T Pagés,
R Rama
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ABSTRACT: The effect of acute hypoxia on blood concentration of ammonia ([NH3]b) and lactate (la-]b) was studied during incremental exercise(IE), and two-step constant workload exercises (CE). Fourteen endurance-trained subjects performed incremental exercise on a cycle ergometer under normoxic (21% O2) and hypoxic (10.4% O2) conditions. Eight endurance-trained subjects performed two-step constant workload exercise at sea level and at a simulated altitude of 5000 m (hypobaric chamber, P(B)=405 Torr; P(O2)=85 Torr) in random order. In normoxia, the first step lasted 25 minutes at an intensity of 85 % of the individual ventilatory anaerobic threshold (AT(vent), ind) at sea level. This reduced workload was followed by a second step of 5 minutes at 115% of their AT(vent), ind. This test was repeated into a hypobaric chamber, at a simulated altitude of 5,000 m. The first step in hypoxia was at an intensity of 65 % of AT(vent), ind., whereas workload for the second step at simulated altitude was the same as that of the first workload in normoxia (85 % of AT(vent), ind). During IE, [NH3]b and [la-]b were significantly higher in hypoxia than in normoxia. Increases in these metabolites were highly correlated in each condition. The onset of [NH3]b and [la-]b accumulation occurred at different exercise intensity in normoxia (181W for lactate and 222W for ammonia) and hypoxia (100W for lactate and 140W for ammonia). In both conditions, during CE, [NH3]b showed a significant increase during each of the two steps, whereas [la-]b increased to a steady-state in the initial step, followed by a sharp increase above 4 mM x L(-1) during the second. Although exercise intensity was much lower in hypoxia than in normoxia, [NH3]b was always higher at simulated altitude. Thus, for the same workload, [NH3]b in hypoxia was significantly higher (p<0.05) than in normoxia. Our data suggest that there is a close relationship between [NH3]b and [la-]b in normoxia and hypoxia during graded intensity exercises. The accumulation of ammonia in blood is independent of that of lactate during constant intense exercise. Hypoxia increases the concentration of ammonia in blood during exercise.
Journal of physiology and biochemistry 12/2001; 57(4):303-12. · 1.71 Impact Factor
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ABSTRACT: This study aimed to determine whether brief hypoxic stimuli in a hypobaric chamber are able to elicit erythropoietin (EPO) secretion, and to effectively stimulate erythropoiesis in the short term. In two different experiments, a set of haematological, biochemical, haemorheological, aerobic performance, and medical tests were performed in two groups of healthy subjects. In the first experiment, the mean plasma concentration of EPO ([EPO]) increased from 8.7 to 13.5 mU.ml-1 (55.2%; P < 0.01) after 90 min of acute exposure at 540 hPa, and continued to rise until a peak was attained 3 h after the termination of hypoxia. In the second experiment, in which subjects were exposed to a simulated altitude of up to 5500 m (504 hPa) for 90 min, three times a week for 3 weeks, all haematological indicators of red cell mass increased significantly, reaching the highest mean values at the end of the programme or during the subsequent 2 weeks, including packed cell volume (from 42.5 to 45.1%; P < 0.01), red blood cell count (from 4.55 x 10(6) to 4.86 x 10(6).l-1; P < 0.01), reticulocytes (from 0.5 to 1.4%; P < 0.01), and haemoglobin concentration (from 14.3 to 16.2 g.dl-1; P < 0.01), without an increase in blood viscosity. Arterial blood oxygen saturation during hypoxia was improved (from 60% to 78%; P < 0.05). Our most relevant finding is the ability to effectively stimulate erythropoiesis through brief intermittent hypoxic stimuli (90 min), in a short period of time (3 weeks), leading to a lower arterial blood desaturation in hypoxia. The proposed mechanism for these haematological and functional adaptations is the repeated triggering effect of EPO production caused by the intermittent hypoxic stimuli.
Arbeitsphysiologie 06/2000; 82(3):170-7. · 2.15 Impact Factor
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Neuropsychiatry, neuropsychology, and behavioral neurology 05/2000; 13(2):148.
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ABSTRACT: The physiological responses to short-term intermittent exposure to hypoxia in a hypobaric chamber were evaluated. The exposure to hypoxia was compatible with normal daily activity. The ability of the hypoxia program to induce hematological and ventilatory adaptations leading to altitude acclimation and to improve physical performance capacity was tested. Six members of a high-altitude expedition were exposed to intermittent hypoxia and low-intensity exercise (in cycle-ergometer) in the INEFC-UB hypobaric chamber over 17 d, 3-5 h x d(-1), at simulated altitude of 4,000 m to 5,500 m. Following this hypoxia exposure program, significant increases were found in packed cell volume (41 to 44.6%; p<0.05), red blood cells count (4.607 to 4.968 10(6) cells x microL(-1); p<0.05), and hemoglobin concentration (14.8 to 16.4 g x dL(-1); p<0.05), thus implying an increase in the blood oxygen transport capacity. Significant differences in exercise blood lactate kinetics and heart rate were also observed. The lactate vs. exercise load curve shifted to the right and heart rate decreased, thus indicating an improvement of aerobic endurance. These results were associated with a significant increase in the ventilatory anaerobic threshold (p<0.05). Significant increases (p<0.05) in pulmonary ventilation, tidal volume, respiratory frequency, O2 uptake, CO2 output and ventilatory equivalents to oxygen (VE/Vo2) and carbon dioxide (VE/co2) were observed at the ventilatory threshold and within the transitional zone of the curves. We conclude that short-term intermittent exposure to moderate hypoxia, in combination with low-intensity exercise in a hypobaric chamber, is sufficient to improve aerobic capacity and to induce altitude acclimation.
Aviation Space and Environmental Medicine 02/2000; 71(2):125-30. · 0.88 Impact Factor
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ABSTRACT: With the ultimate goal of finding a straightforward protocol for acclimatization at simulated altitude, we evaluated the early effects of repeated short-term exposure to hypobaric hypoxia on the respiratory response to exercise in hypoxia.
Nine subjects were exposed to a simulated altitude of 5000 m for 2 hours a day for 14 days. Arterial oxygen saturation (SaO2), expired volume per minute (VE), respiratory rate, tidal volume (VT), and heart rate were measured during rest and during exercise (cycloergometer, at 30% of maximum oxygen consumption at sea level), both in normoxia and at 5000 m of simulated altitude on the first and 15th days. On the same days, blood samples were obtained for hematological tests.
During exercise in hypoxia, SaO2 rose from 65 to 71% (P = .02), and VE rose from 55.5 to 67.6 L.min-1 (P = .02) due to an increase in VT from 2 to 2.6 L (P = .003). No significant differences were found in any of the variables studied at rest either in normoxia or in hypoxia or in exercise in normoxia after the exposure program. In the second week, changes in packed cell volume and blood hemoglobin concentration were nonsignificant.
After short-term intermittent exposure to hypobaric hypoxia, subjects increased their ventilatory response and SaO2 during exercise at simulated altitude. These changes may be interpreted as acclimatization to altitude. The monitoring of ventilatory response and SaO2 during moderate exercise in hypobaric hypoxia may be used to detect the first stages of acclimatization to altitude.
Wilderness and Environmental Medicine 02/2000; 11(2):84-8. · 0.94 Impact Factor
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ABSTRACT: L'exposition prolongée en altitude est utilisée depuis plusieurs décennies dans la préparation des athlètes. A partir de trois semaines, elle entraîne des modifications physiologiques (acclimatation) comme l'augmentation de la masse érythrocytaire, d'où l'amélioration des performances au niveau de la mer. Mais la difficulté de maintenir un entraînement de qualité en altitude a imposé l'utilisation de chambres hypobares, permettant ainsi de vivre en altitude et de s'entraîner au niveau de la mer. Afin de déterminer les effets de l'hypoxie sur les réponses ventilatoires et érythropoïétiques, et sur les performances aérobies, deux groupes de sujets ont été confrontés parallèlement à deux types de protocole dans la chambre hypobare de l'INEFC-UB (Barcelone, Espagne) dont l'altitude simulée initialement à 4000 m est augmentée jour après jour: ○ une exposition totale de 30 à 60 heures à raison de 3 à 5 heures par jour (protocole intensif), ○ une exposition totale de 14 heures à raison de 1 heure et demie par jour, et alternée un jour sur deux (protocole allégé). Des prélèvements veineux ont été effectués avant et au moins 22 jours après la fin du protocole afin de déterminer les profils hématologiques (hémoglobine, réticulocytes...) et hémorhéologique (viscosité apparente et relative). Dans le même temps, la performance a été mesurée par un test triangulaire sur tapis roulant (données ventilatoires et taux de lactates). Les résultats montrent dans chacun des protocoles: ○ une augmentation du volume des cellules sanguines, du taux d'hémoglobine et des réticulocytes, ○ une amélioration similaire des performances aérobies, ○ une absence d'hémoconcentration ou d'hémodilution, ○ un profil hémorrhéologique inchangé. Ces modifications seraient dues à la sécrétion d'érythropoïétine. En conclusion, il semblerait que le protocole allégé soit plus efficace que le protocole intensif.
Médecine du Sport. 01/2000; 74(2):32-34.
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ABSTRACT: Blood lactate concentrations in capillary samples obtained from the ear lobe or from the finger tip are used indistinctly, since they are considered equivalents. The aim of the study reported in this paper was to verify whether that assumption is valid due to the practical implications which any possible differences between these two sampling sites would have in the planning and assessing of an athletic training program. Twenty six healthy male athletes competing in different sports at the national level (9 rowers, 7 cyclists and 10 runners) were studied during the performance of a graded exercise test up to the point of exhaustion, on specific ergometers. In each group, capillary blood samples were obtained simultaneously from both the ear lobe and the finger tip at three different times during the test: 1) in resting conditions; 2) when exercising at a submaximal work load and 3) seven minutes after the point of exhaustion. Significant differences were found between the blood lactate concentrations of samples obtained from the ear lobe and from the finger tip (p < 0.001). The method error of repeated measurements for lactate concentrations from paired samples obtained in resting conditions was 27%, when exercising at a submaximal work load, 16% and at maximal work load, 3%. Capillary blood samples collected from the finger tip consistently showed higher values in lactate concentration than those obtained, at the same time, from the ear lobe.
Journal of physiology and biochemistry 01/2000; 55(4):333-9. · 1.71 Impact Factor
