PubMed Health⌕ Search

Biomedical subjects

E Baraldi

Publications and source records attributed to E Baraldi.

At least 37 records · Page 2Linked to original sources
PubMed1997

Exercise performance in children with asthma: is it different from that of healthy controls?

Exercise tolerance and possible limitation in work capacity of asthmatic children is still a matter of debate. The aim of this study was to compare ventilation and gas exchange response to exercise of asthmatic children with that of healthy controls. Exercise performance was evaluated in 80 children with mild-to-moderate asthma, aged 7-15 yrs, and in 80 healthy controls matched for age, height, weight and habitual level of physical activity. The children performed a maximal exercise test on a treadmill, during which oxygen uptake (V'O2), carbon dioxide output (V'CO2) and minute ventilation (V'E) were measured continuously. No premedication was given to the asthmatic children. Forced expiratory volume in one second (FEV1) at rest was 93+/-11% of predicted in asthmatic children and 95+/-9% pred in controls. After the run, the mean fall in FEV1 was 13.9% (range 0-57%) and 1.6% (0-9%), respectively (p<0.001). The two groups achieved similar maximum oxygen uptake (V'O2,max) ((mean+/-SD) 40.3+/-8.4 and 42.6+/-9.6 mL x min(-1) x kg(-1) in asthmatics and controls, respectively; NS) and maximum minute ventilation output (V'E,max) (42.9+/-14.8 and 45.7+/-14.9 L x min(-1) respectively; NS). The kinetics of V'O2, V'CO2 and V'E during the test revealed no differences between the two populations. Moreover, anaerobic threshold and oxygen pulse were the same in the two groups. Asthmatics showed a ventilatory pattern with lower respiratory frequencies and greater tidal volumes during the run. These results suggest that asthmatic children can achieve a level of exercise performance similar to that of healthy children, provided that they have a comparable level of habitual physical activity. The only difference found concerned the ventilatory pattern of the asthmatic children, which was characterized by a reduced respiratory frequency and greater tidal volume at the same minute ventilation. The level of physical conditioning was found to be the main determinant of exercise tolerance for children with controlled asthma.

Adolescent↗
PubMed1996

Structure of the WW domain of a kinase-associated protein complexed with a proline-rich peptide.

The WW domain is a new protein module with two highly conserved tryptophans that binds proline-rich peptide motifs in vitro. It is present in a number of signalling and regulatory proteins, often in several copies. Here we investigate the solution structure of the WW domain of human YAP65 (for Yes kinase-associated protein) in complex with proline-rich peptides containing the core motif PPxY. The structure of the domain with the bound peptide GTPPPPYTVG is a slightly curved, three-stranded, antiparallel beta-sheet. Two prolines pack against the first tryptophan, forming a hydrophobic buckle on the convex side of the sheet. The concave side has three exposed hydrophobic residues (tyrosine, tryptophan and leucine) which form the binding site for the ligand. A non-conserved isoleucine in the amino-terminal flanking region covers a hydrophobic patch and stabilizes the WW domain of human YAP65 in vitro. The structure of the WW domain differs from that of the SH3 domain and reveals a new design for a protein module that uses stacked aromatic surface residues to arrange a binding site for proline-rich peptides.

Adaptor Proteins, Signal Transducing↗
PubMed1995

Factors limiting exercise performance in long-term survivors of bronchopulmonary dysplasia.

The long-term impairment of pulmonary function during exercise was assessed in 12 children, aged 6 to 12 yr, who developed BPD after prematurity (gestational age 30 +/- 2 wk [mean +/- SD] and birth weight 1,400 +/- 335 g) and 16 age-, sex-, and physical activity-matched healthy children born at term, who served as controls. The children performed pulmonary function tests at rest and a maximal stepwise exercise on a treadmill. Oxygen consumption (VO2), carbon dioxide output (VCO2), and minute ventilation (VE) were monitored during the run. Baseline mean spirometric values (% of predicted) were in the normal range for both groups but were lower in BPD children with respect to control children (p < 0.05). At rest, arterial oxygen saturation (SaO2) was > or = 98% in all BPD children, but at peak exercise, 4 of them had a SaO2 fall > or = 4%. The postexercise FEV1 fall, with respect to the baseline, was 8 +/- 6%, in BPD and 2 +/- 1% in control children (p < 0.01). Maximum VO2 and VE were significantly lower in BPD children with respect to the control group (25.2 +/- 10.3 versus 37.1 +/- 10.4 ml/min/kg and 20.8 +/- 9.4 versus 30.7 +/- 7.9 L/min, respectively, both p < 0.01). Also, at submaximal levels of exercise dynamic, VO2 and VE responses were significantly lower in the BPD group (ANOVA, p < 0.001), with a ventilatory pattern characterized by lower tidal volumes. Anaerobic threshold was 20.6 +/- 9 in BPD and 28.8 +/- 8.6 ml O2/min/kg in healthy children (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Bronchopulmonary Dysplasia↗
PubMed1994

Effect of beclomethasone dipropionate on bone mineral content assessed by X-ray densitometry in asthmatic children: a longitudinal evaluation.

There is little information on bone turnover in asthmatic children taking long-term treatment with inhaled steroids (ICS). The aim of this longitudinal study was to determine the effects of inhaled beclomethasone dipropionate (BDP) on bone mineral density (BMD), in asthmatic children treated over a period of six months. BMD and growth were studied in two age- and sex-matched groups of asthmatic children. These comprised: 14 asthmatic children (Group 1) who had taken BDP in a dosage of 300-400 micrograms daily through a 145 ml spacer device for at least 6 months (mean age 9.1 yrs); and a control group of 16 age- and sex-matched asthmatic patients (Group 2) not treated with ICS (mean age 9.5 yrs). Mean duration of asthma was 5.7 yrs in Group 1 and 5.5 yrs in Group 2. Vertebral BMD (L2-L4) was measured by dual energy X-ray absorptiometry (DEXA) at the beginning (baseline) of the study and 6 months later. There were no significant differences in the baseline bone mass (mean +/- SEM) between the two groups (0.63 +/- 0.03 and 0.64 +/- 0.02 g.cm-2 in Group 1 and 2, respectively). During the observation period, bone density increased, by 4% (95% confidence interval (95% CI) 2-6) in the control group and by 2.3% (95% CI 0.4-4.2) in the group under BDP treatment, showing no significant influence of the treatment. No difference was found in height velocity evaluated before starting BDP and after 6 months of therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1994

Effect of disodium cromoglycate on ventilation and gas exchange during exercise in asthmatic children with a postexertion FEV1 fall less than 15 percent.

The purpose of this study is to evaluate the effect of disodium cromoglycate (DSCG) on gas exchange and ventilation during incremental exercise in asthmatic children with an FEV1 fall less than 15 percent from the baseline after the exercise. Seventeen children (aged 8 to 14 years) with a history of mild to moderate asthma but no clinical and spirometric evidence of exercise-induced asthma (EIA) underwent two maximal exercise tests in a randomized order: test A without premidication and test B after inhalation of DSCG, 40 mg. To evaluate the effect of DSCG on normal airways, nine healthy children performed the same exercise protocol. Pulmonary function was normal at rest and after treadmill exercise test (the mean postexercise fall in FEV1 was 5.9 percent in test A and 1.5 percent in test B). Gas exchange, minute ventilation (VE) and heart rate (HR) were monitored during running in both tests. In the asthmatic subjects, there were no differences in oxygen uptake (VO2), carbon dioxide output (VCO2), and VE at rest between the two tests. During exercise, VE, VO2, VCO2, and energy cost (EC[O2 ml.kg-1.m-1]) of running in the asthmatic subjects were significantly lower in test B than in test A (analysis of variance, p < 0.01) for comparable work rates. Maximal minute ventilation (VEmax) was significantly higher in test A (46.9 +/- 14.6[+/- SD]L.min-1) than in test B (43.2 +/- 14 L. min-1; p < 0.05). We found no significant effect of DSCG on gas exchange and ventilation during exercise in the healthy children (VEmax 47.8 +/- 25 and 48.4 +/- 25 L.min-1 in test A and B, respectively). In conclusion, premedication with DSCG appears to decrease the ventilatory cost of exercise in asthmatic children who do not present a substantial fall in FEV1 after an exercise test without pretreatment.

Asthma↗
PubMed1994

Passive respiratory mechanics to assess lung function in infants.

In the last decade, the development of a number of ingenious techniques has led to the possibility of evaluating respiratory mechanics from the neonate up to children 3-4 yrs of age. Among these methods, the single-breath occlusion (SBO) technique and the multiple occlusion (MO) technique have gained extensive acceptance, and are used both in spontaneously breathing and mechanically-ventilated infants. These techniques allow the assessment of the passive mechanics of the total respiratory system (compliance, resistance and time constant), by evoking the Hering-Breuer inflation reflex, which results in relaxation of both inspiratory and expiratory muscles. These methods are suitable for repeated assessment in small infants and for longitudinal studies, because of their low invasivity, high reproducibility and relatively simple application. Pulmonary function tests may represent a useful guide in diagnosis, monitoring, prediction of outcome, and management assessment in infants and children with lung diseases. However all these techniques are limited by implicit assumptions and further developments towards simpler methods are needed.

Child, Preschool↗
PubMed1993

Rapid improvement of static compliance after surfactant treatment in preterm infants with respiratory distress syndrome.

Respiratory mechanics were measured in 20 preterm infants before and in the 24-hr period after treatment with surfactant. All infants were enrolled in the rescue clinical trial with Curosurf carried out in the Neonatal Intensive Care Unit. They received a dose of 200 mg/kg lipid surfactant intratracheally after birth. Static compliance of the respiratory system (Crs) was measured by the single breath occlusion technique during both spontaneous and mechanical ventilation. Resistance of the respiratory system (Rrs) and expiratory time constant (Trs) were also measured. As early as 3 hr after surfactant administration a significant improvement of 45% in Crs measured during mechanical ventilation (CrsV) was noted (0.40 +/- 0.14 vs 0.58 +/- 0.17 mL/cm H2O/kg, P < 0.001), together with a significant improvement of the arterial/alveolar O2 tension ratio (Pa/AO2) (0.12 +/- 0.03 vs 0.30 +/- 0.16, P < 0.01). The improvement of CrsV and Pa/AO2 was confirmed 24 hr later (0.55 +/- 0.15 mL/cm H2O/kg and 0.33 +/- 0.18, respectively). A significant correlation was found between Crs and Pa/AO2 ratio (r = 0.56, P < 0.001). Time constant values were significantly higher after surfactant treatment (0.15 +/- 0.07 vs 0.09 +/- 0.03 sec; P < 0.01). Rrs remained unchanged. These data indicate that Curosurf given intratracheally after birth determines a rapid improvement of respiratory mechanics as soon as 3 hr after dosing, together with the improvement of oxygenation. From the findings obtained with the present study we show evidence that respiratory system mechanics may be a useful physiological measure to guide ventilatory strategy following surfactant therapy.

Airway Resistance↗
PubMed1993

Respiratory mechanics in infants and young children before and after repair of left-to-right shunts.

In an attempt to investigate the relationship between respiratory mechanics and pulmonary hemodynamics, we evaluated pulmonary function in 31 infants with left-to-right shunts and subsequent high pulmonary blood flow, undergoing cardiac surgery. Measurements were performed 1 d before and repeated 10 d and 4-5 wk after correction. The age of the patients ranged from 4 d to 24 mo, body weight from 2.7 to 11.8 kg. Pulmonary artery pressure, assessed by Doppler echocardiography, was preoperatively elevated in 23 patients (group 1), whereas it was within normal values in eight infants (group 2). Respiratory mechanics were measured using the single-breath occlusion technique in sedated infants. To evaluate specific compliance, functional residual capacity was determined by using an open circuit nitrogen washout technique. A reduced preoperative compliance value (mean with 95% confidence interval) was found in group 1: 34.8 (26.5-43.1) mL.kPa-1. After hemodynamic correction, a progressive significant (p < 0.01) improvement was demonstrated at 10 d and 1 mo with values of 47.5 (39.2-55.8) mL.kPa-1 and 56.5 (45.6-67.4) mL.kPa-1, respectively. A similar trend was noted evaluating specific compliance with values of 0.27 (0.24-0.30) kPa-1 and 0.44 (0.42-0.46) kPa-1, respectively before and after surgery. Preoperative functional residual capacity value was 130 (100-160) mL. In group 2, normal preoperative compliance values were obtained, without significant changes after surgery. In both groups, resistance was within the normal range both before and after surgical correction, and functional residual capacity did not change either. No correlations were found between compliance and pulmonary artery pressure and pulmonary blood flow values.(ABSTRACT TRUNCATED AT 250 WORDS)

Child, Preschool↗
PubMed1992

Gas exchange during exercise in diabetic children.

The purpose of this study was to evaluate the cardiorespiratory and metabolic response to exercise in 33 children, aged 9 to 15 years, affected by type I diabetes mellitus, in comparison with 47 age-, sex-, weight-, and height-matched healthy children. All diabetic children were on a mixed split-dose insulin regimen, consisting of both regular and long-acting insulin in the morning and evening. The last insulin injection was administered on average 6 hours before the test. The mean duration of diabetes mellitus was 5.0 +/- 3.1 years. The metabolic control was evaluated on the basis of HbA1 levels (mean, 8.9 +/- 1.8%). Pulmonary function tests and progressive exercise tests on the treadmill were performed. Gas exchange, ventilation, and heart rate (HR) were monitored during the tests. The O2 pulse (VO2/HR) was calculated. There was no difference in the baseline oxygen uptake (VO2) between the diabetic children and the control group. VO2 peak was significantly lower (P less than 0.01) in the diabetic adolescents (41.2 +/- 5.9 mL/min/kg) compared to control subjects (46.3 +/- 9.6 mL/min/kg) and it was achieved at an earlier (P less than 0.01) time of run (7.5 +/- 1.8 vs. 9.1 +/- 2.8 min). Anaerobic threshold and minute ventilation were similar in the two groups. The O2 pulse throughout the test was significantly lower (ANOVA, P less than 0.001) in the diabetic group compared to the controls. No differences were found in resting and post-exercise spirometric values. In conclusion, our study shows that well-controlled diabetic adolescents have a reduced working capacity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Exercise performance in very low birth weight children at the age of 7-12 years.

Fifteen very low birth weight children, 9 appropriate for gestational age (AGA, mean birth weight 1302 +/- 164 g) and 6 small for gestational age children (SGA, mean birth weight 1263 +/- 117 g), were studied at the age of 7-12 years, and compared to a group of 26 healthy, age-, sex-, and height-matched children born at term. None of the VLBW children had developed chronic bronchopulmonary disease. Pulmonary function tests and progressive exercise tests on a treadmill were performed. Forced vital capacity, forced expiratory volume at 1 s and forced expiratory flow between 25% and 75% of vital capacity were normal for all subjects. No differences were found in maximum oxygen consumption, anaerobic threshold and maximal heart rate between the AGA and SGA children and the respective controls. Both in the AGA and SGA subgroups, the pre-exercise oxygen uptake results were comparable to those of the controls. In the SGA subgroup the energy cost of running was significantly higher with respect to the controls, while no difference was found between the AGA and the control children. In conclusion, children with birth weight less than 1501 g have normal values of aerobic fitness. In SGA children the efficiency of running is slightly reduced.

Anaerobic Threshold↗
PubMed1991

Heart rate recovery from 1 minute of exercise in children and adults.

Previous studies demonstrated that the time required for oxygen uptake, CO2 production, and minute ventilation to return to baseline levels after 1-min bursts of exercise is different in children compared with adults. To test the hypothesis that the heart rate (HR) recovery time after exercise is also different in children compared with adults, we examined HR in 10 children (range 7-11 y old) and 12 adults (26-42 y old) for 10 min after 1 min of cycle ergometer exercise. Each subject exercised at work rates corresponding to 80% of the lactate or anaerobic threshold (AT), 50% of the difference between AT and maximal O2 uptake (delta), 100% of maximal uptake, and 125% of maximal uptake. Gas exchange was measured breath by breath. In adults, the HR recovery time increased significantly with work intensity as judged by the time constant of a single exponential curve fit to postburst-exercise HR [23 +/- 8 (SD) s at 80% AT, 55 +/- 16 at 50% delta, 74 +/- 13 at 100% of maximal uptake, and 83 +/- 20 at 125% of maximal uptake]. HR recovery time tended to increase with work intensity in children (16 +/- 7, 20 +/- 4, 23 +/- 7, and 27 +/- 9; for 80% AT, 50% delta, 100% of maximal uptake, and 125% of maximal uptake respectively), but to a much smaller extent, and the HR recovery time was significantly smaller in children in the high-intensity (above AT) range of exercise (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Effect of inhaled disodium cromoglycate and albuterol on energy cost of running in asthmatic children.

The purpose of this study is to evaluate the effect of disodium cromoglycate and albuterol on energy cost of running, gas exchange, and ventilation during maximal exercise in children with exercise-induced asthma (EIA). Twelve children (7.1-15.5 years old) with a history of mild to moderate asthma and EIA performed three maximal exercise tests on a treadmill: 1) test A, without premedication; 2) test B, after premedication with inhaled disodium cromoglycate (DSCG) (40 mg); 3) test C, after premedication with inhaled albuterol (200 micrograms). The energy cost of running was calculated at each minute of exercise. None of the children were limited by dyspnea during the run. The post-exercise fall in FEVi after test A was greater than 20% for each child, the mean fall being 32.8 +/- 11.6%, in comparison with 12.6 +/- 8.9% after test B (P less than 0.001) and 2.5 +/- 5.3% after test C (P less than 0.001). There was no difference in the baseline oxygen uptake for the three tests. Maximum oxygen uptake (VO2 peak) decreased from 43.9 +/- 7.7 mL/min/kg in test A to 37.7 +/- 6.0 mL/min/kg in test B (P less than 0.01) and 39.1 +/- 7.2 mL/min/kg in test C (P less than 0.05). Ventilatory anaerobic threshold in tests B and C was significantly lower than in test A (P less than 0.01). Ventilation (L/min) and energy cost of running (O2 mL/kg/m) were significantly lower in tests B and C than in test A at comparable times. Running time was longer in B and C (P less than 0.05) with respect to A.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗
PubMed1990

Exercise tolerance after anaemia correction with recombinant human erythropoietin in end-stage renal disease.

The aim of this study was to evaluate the effect of correction of chronic anaemia on the physical performance and the cardiovascular response to effort in children with end-stage renal disease (ESRD) maintained by haemodialysis. Seven patients (mean age 13.9 years) underwent triangular-type treadmill exercise testing before [haemoglobin (Hb) 6.3 +/- 0.9 g/dl] and after (Hb 11.2 +/- 1.2 g/dl) anaemia correction with recombinant human erythropoietin (rHuEPO). After treatment, the work-load reached, the peak oxygen uptake and average ventilatory anaerobic threshold (VAT) values were significantly increased (P less than 0.01, P less than 0.001, P less than 0.05 respectively). VAT values, expressed as a percentage of normal values, increased from 55.7 +/- 16.6% to 82.4 +/- 21%. This improvement correlated well with the increase in Hb (r = 0.79). Oxygen pulse also increased significantly, when tested after anaemia correction. In conclusion, these data demonstrate that when the anaemia of children with ESRD is corrected with rHuEPO, there is a clear improvement in aerobic work capacity and effort tolerance.

Adolescent↗
PubMed1990

Benefits and risks of anemia correction with recombinant human erythropoietin in children maintained by hemodialysis.

Ten children with renal failure (age range 2 years 6 months to 18 years 9 months; median 11 years 10 months), maintained by long-term hemodialysis, had successful correction of their anemia after intravenous administration of recombinant human erythropoietin in a dosage escalating every 2 weeks (75 to 150 to 300 to 450 IU/kg/wk). Mean hemoglobin concentration increased from 6.4 +/- 0.9 to 11.5 +/- 1.0 gm/dl. Blood cell counts used to evaluate the correction of anemia were done after dialysis; this was especially important for children less compliant with water restriction. The higher hemoglobin concentration resulted in improvement of the quality of life, a greater tolerance for physical effort (exercise tolerance doubled and the ventilatory anaerobic threshold increased significantly), correction of some subclinical central nervous system abnormalities detected by evoked potentials testing, and reduction of bleeding time. Few side effects were noted; severe hypertension developed in one patient when postdialysis hematocrit was only 28%, and there were two episodes of hypertransaminasemia with no other evidence of liver dysfunction. We conclude that in children with renal failure the use of recombinant human erythropoietin to correct anemia is safe and strongly advisable, because of the resolution of many of the symptoms correlated with anemia.

Adolescent↗
PubMed1990

Exercise tolerance in end-stage renal disease.

The cardiorespiratory and metabolic response to exercise was evaluated in children with end-stage renal failure maintained on haemodialysis. Eight patients (haemodialysis group), 4 boys and 4 girls, with a mean age of 13.4 +/- 3.6 years (range 9.4-18.6 years) and haemoglobin levels ranging from 5.3 to 7.6 g/dl and 16 healthy children (control group) performed a progressive exercise testing on a treadmill. Gas exchange was simultaneously monitored. The mean ventilatory anaerobic threshold of the haemodialysis group, expressed as a percentage of the reference values, was 59.1 +/- 18.2%, and their maximum work load (29.9 +/- 19 W) was about one fourth of that reached by the control group (113.3 +/- 51.6 W). Ventilatory anaerobic threshold values in the haemodialysis group significantly correlated with blood haemoglobin levels, but not with creatinine and parathyroid hormone concentrations. We, therefore, conclude (1) that children maintained on chronic haemodialysis have a marked reduction in aerobic working capacity and (2) that the major cause for this limitation appears to be the reduced haemoglobin concentration.

Adolescent↗
PubMed1989

Gas exchange during exercise in obese children.

Twenty-three obese children, aged 9 to 14 years, ranging in percentage overweight from 26% to 83% (median 51.6% +/- 16.3%), and 37 normal-weight children, matched for sex, age and height, performed a maximal exercise test on a treadmill. Cardiorespiratory performance was assessed by determination of the ventilatory anaerobic threshold (VAT) expressed in ml O2/min per kg and as a percent of maximal oxygen uptake (% VO2max). VAT and VO2max related to body weight were significantly lower (P less than 0.01) in the obese than in the normal-weight children. VAT % VO2max was similar in the two groups. A significant correlation was found between VAT and VO2max both in the obese (r = 0.85) and in the control groups (r = 0.79). The habitual level of physical activity was lower in the obese subjects compared to the control subjects (P less than 0.001). In conclusion our study shows that physical fitness of overweight children is quantitatively lowered and that it can be assessed by VAT. VAT does not require a maximal test and is particularly useful in the ergometric study of subjects with exercise intolerance.

Adolescent↗
PubMed1989

A comparison of two noninvasive methods in the determination of the anaerobic threshold in children.

Seventy children, ranging in age from 7 to 14 years, performed a maximal exercise test on a treadmill with determination of the anaerobic threshold (AT) by two methods: (1) with the gas exchange method the ventilatory anaerobic threshold (VAT) was identified by the increase in the ventilatory equivalent for O2 uptake without a concomitant increase in the ventilatory equivalent for CO2 output and (2) with the method proposed by Conconi, the AT was taken at the point beyond which the increase in work intensity exceeded the increase in heart rate and the linearity of the work rate/heart rate relationship was lost. The AT values measured with the two methods were correlated (r = 0.80, P less than 0.001). This result confirms, also in children, the validity of the simple Conconi method: It can be used particularly for the determination of the individual optimal intensity of training.

Adolescent↗