Comparison of reaction time and functional balance in chronic obstructive pulmonary disease and healthy participants

BackgroundReaction time is one of the components of functional balance and could contribute to balance impairment. Information regarding this relationship is scant among Chronic Obstructive Pulmonary Disease (COPD) participants.ObjectivesTo compare stepping reaction time between participants with COPD and age; gender-matched healthy individuals to find out whether reaction time in COPD population is affected.MethodsThis cross-sectional study included 41 COPD participants and 41 age and gender-matched healthy individuals. All the participants underwent measurements of stepping reaction time (SRT) and timed up and go test (TUG).ResultsSRT was significantly higher in COPD participants compared to healthy individuals [median of difference- 350 milliseconds (110, 830), p < 0.001]. TUG was significantly higher in COPD participants compared to healthy individuals [median of difference = 2.82 seconds (0.34 and 4.5), p < 0.001].ConclusionsParticipants with COPD exhibit marked increase in SRT and demonstrate a deficiency in functional balance compared to the healthy participants.     

Acute cardiac effects of nicotine in healthy young adults

BACKGROUND: Nicotine is known to have many physiologic effects. The influence of nicotine delivered in chewing gum upon cardiac hemodynamics and conduction has not been well-characterized. METHODS: We studied the effects of nicotine in nonsmoking adults (6 male, 5 female; ages 23-36 years) using a double-blind, randomized, cross-over study. Subjects chewed nicotine gum (4 mg) or placebo. After 20 minutes (approximate time to peak nicotine levels), echocardiograms and signal-averaged electrocardiograms (SAECG) were obtained. After 40 minutes, subjects were again given nicotine gum or placebo in cross-over fashion. Standard echocardiographic measurements were made from two-dimensional images. We then calculated end-systolic wall stress (ESWS), shortening fraction (SF), systemic vascular resistance (SVR), velocity for circumferential fiber shortening corrected for heart rate (Vcfc), stroke volume, and cardiac output. P wave and QRS duration were measured from SAECG. Results: Significant differences (P < 0.05) from control or placebo were found for ESWS, mean blood pressure, cardiac output, SVR, heart rate, and P wave duration. No significant changes were seen in left ventricular ejection time (LVET), LV dimensions, SF, contractility (Vcfc), or QRS duration. CONCLUSIONS: These results suggest that nicotine chewing gum increases afterload and cardiac output. Cardiac contractility does not change acutely in response to nicotine gum. Heart rate and P wave duration are increased by chewing nicotine gum.     

Short-term effects of exercise and music on cognitive performance among participants in a cardiac rehabilitation program

OBJECTIVE: Exercise has been associated with improved cognitive performance among patients with coronary artery disease. Music listening has been associated with enhanced cognitive functioning among healthy adults. This study evaluated the combined influence of exercise and music listening on cognitive performance among patients in cardiac rehabilitation (CR). DESIGN AND SETTING: Using a within-subjects repeated measures design, this study was conducted in an outpatient University-based CR facility. SAMPLE: Thirty-three men and women (mean age = 62.6 +/- 10.5 years) participated in this study. METHODS: Participants completed 1 exercise session accompanied by music and a second exercise session without music. Order of conditions was assigned randomly. Before and after each exercise session, participants completed a brief assessment of depression and anxiety, and a cognitive test of verbal fluency. RESULTS: The music condition was associated with significant improvements in verbal fluency, but the no-music control condition was not associated with cognitive change. CONCLUSION: The study provides preliminary evidence of the combined benefit of exercise and music listening for cognitive performance among patients in CR.     

Sedentary behavior and physical activity in cardiac rehabilitation participants

Background

There is a deleterious association between sedentary behavior and mortality risk factors. Elevated sedentary time has been reported in several studies that involved cardiac rehabilitation (CR) participants.

Sympathomimetic infusion and cardiac repolarization: the normative effects of epinephrine and isoproterenol in healthy subjects

Introduction: Catecholamines are known to affect cardiac repolarization, and provocation with either isoproterenol or epinephrine has been proposed as a tool for uncovering latent repolarization abnormalities. This study systematically compares the effects of isoproterenol and epinephrine infusions on QT interval (QT), T waves and U waves in normal subjects.
Methods and Results: Twenty-four normal subjects (29 ± 8 years) were evaluated during graded infusions of up to 0.30 μg/kg/minute epinephrine and 5.0 μg/minute isoproterenol. Heart rates at peak doses were 81 ± 13 bpm at 0.28 ± 0.04 μg/kg/minute epinephrine and 104 ± 5 bpm at 2.4 μg/minute isoproterenol. The longest absolute QT increase was 4 ± 5 msec above baseline during isoproterenol (P < 0.001) and 12 ± 23 msec during epinephrine (P = 0.07), while the longest corrected QT interval (QTc) increase was 67 ± 28 msec (P < 0.0001) and 79 ± 40 msec (P < 0.0001) above baseline during isoproterenol and epinephrine, respectively (P = 0.12 for difference). There was a 2-fold increase in U-wave amplitude during each intervention (P < 0.001). The specificity of paradoxical QT prolongation (≥30 msec at 0.05 μg/kg/minute or ≥35 msec at 0.10 μg/kg/minute epinephrine) and an increase in QTc ≥600 msec at any dose epinephrine were 100%. However, the specificity of other proposed criteria that utilized QTc measurement (≥30 msec at 0.10 μg/kg/minute or ≥65 msec at any dose) was poor whether all leads or only lead II were assessed.
Conclusion: Both epinephrine and isoproterenol are associated with QTc prolongation and amplification of the U wave in normal subjects. The specificity of proposed criteria for epinephrine provocation in diagnosis of the long-QT syndrome is variable; however, paradoxical QT prolongation at low-dose epinephrine or a QTc ≥600 msec is highly specific.     

Comparison between the cardiac effects induced by muzolimine and furosemide in guinea-pig atria

Summary Muzolimine (10–500 M) induced a concentration-dependent reduction of both the contractile force and frequency in spontaneously beating atria and in electrically driven left atrium from reserpine-treated guinea pigs. This negative inotropic response was unaffected by the addition of atropine to the perfusion fluid, and it was highly sensitive to changes in external Ca²⁺ concentration. Both in spontaneously beating and in electrically driven atrium, muzolimine (50–400 M) antagonized, in an apparently competitive manner, the increase in contractile force induced by cumulative addition of CaCl₂ (0.68–9.59 mM) to the bathing fluid. Muzolimine (50–100 M) reduced the inotropic response to low (5–30 nM), but not high (50–100 nM) concentrations of Bay K 8644, a calcium-channel agonist. The inotropic effects of 8-phenyltheophylline and of ouabain were antagonized by muzolimine (10–100 M) in a noncompetitive manner, while the response to noradrenaline was not altered. Similar to muzolimine, verapamil at a concentration suitable to block calcium channels inhibited, in a noncompetitive way, the inotropic effect induced by 8-phenyltheophylline and by ouabain without altering the contractile response to noradrenaline. Furosemide (10 and 100 M) did not influence the contractile force or the frequency of spontaneously beating atria, nor the inotropic effect induced by CaCl₂, 8-phenyltheophylline, ouabain, or noradrenaline. These results indicate that the influence of muzolimine on guinea-pig atria originates from an inhibition of Ca²⁺ influx into cardiac cells and that furosemide does not mimic the effect of muzolimine at this level.     

Haemoglobinuria in a case of Falciparum malaria treated with co-artemether

The first reported case of haemoglobinuria in a patient treated with co-artemether for falciparum malaria is described.     

Serum albumin and muscle measures in a cohort of healthy young and old participants

Consensus on clinically valid diagnostic criteria for sarcopenia requires a systematical assessment of the association of its candidate measures of muscle mass, muscle strength, and physical performance on one side and muscle-related clinical parameters on the other side. In this study, we systematically assessed associations between serum albumin as a muscle-related parameter and muscle measures in 172 healthy young (aged 18–30 years) and 271 old participants (aged 69–81 year) from the European MYOAGE study. Muscle measures included relative muscle mass, i.e., total- and appendicular lean mass (ALM) percentage, absolute muscle mass, i.e., ALM/height² and total lean mass in kilograms, handgrip strength, and walking speed. Muscle measures were standardized and analyzed in multivariate linear regression models, stratified by age. Adjustment models included age, body composition, C-reactive protein and lifestyle factors. In young participants, serum albumin was positively associated with lean mass percentage (p = 0.007) and with ALM percentage (p = 0.001). In old participants, serum albumin was not associated with any of the muscle measures. In conclusion, the association between serum albumin and muscle measures was only found in healthy young participants and the strongest for measures of relative muscle mass.     

The physical activity patterns of cardiac rehabilitation program participants

PURPOSE: This investigation aimed to examine the physical activity patterns of cardiac rehabilitation program (CRP) participants. METHODS: The investigation enrolled 53 male and 24 female CRP participants between 46 and 88 years of age. By means of a uniaxial accelerometer (Life-Corder), the amount of physical activity (in kilocalories) and the time spent in physical activity at light (<3 metabolic equivalents [METs]), moderate (3 to 6 METs), and vigorous (>6 METs) intensity were evaluated. In addition to these variables, the MET levels for the CRP and non-CRP periods were calculated. RESULTS: The weekly amount of physical activity energy expenditure averaged 1597 +/- 846 kcal/week, and the time spent in light, moderate, and vigorous physical activity averaged, respectively, 375.5 +/- 124.5 minutes, 125.2 +/- 109.4 minutes, and 5.7 +/- 12.8 minutes per week. These levels were significantly lower on non-CRP days than on CRP days: 177 +/- 113 versus 299 +/- 161 kcal/day and, respectively, 49.3 +/- 19.3 versus 59.7 +/- 19.8 minutes, 10.5 +/- 14.6 versus 26.4 +/- 20.4 minutes, and 0.4 +/- 1.7 versus 1.4 +/- 3.0 minutes per day. CONCLUSIONS: These results indicate that the amount of physical activity was generally adequate on CRP days, but failed to reach target levels on non-CRP days. Thus CRP participants, when it is medically appropriate, should be encouraged to incorporate lifestyle physical activity, additional exercise, or both on non-CRP days to supplement their caloric expenditure from CRP exercise sessions.     

Comparison of the effects of gastric antisecretory agents in healthy volunteers and patients with duodenal ulcer.

Thirty published studies of the clinical pharmacology of gastric antisecretory agents in normal volunteers and duodenal ulcer patients were reviewed. The aim was to investigate the relationship between antisecretory effect in the two populations. There was a significant correlation between effect in patients and normal subjects for suppression of 24 hour intragastric acidity (r = 0.732; p = 0.0068), nocturnal intragastric acidity (r = 0.861; p = 0.0033) and nocturnal acid output (r = 0.964; p = 0.0069). The regression lines for 24 hour and nocturnal acidity were very similar. The expected antisecretory effect of a particular dosage regimen in patients with duodenal ulcer can be predicted mathematically from data derived from studies in normal volunteers.     

Stage-specific effects of antimalarials on an Indian isolate of Plasmodium falciparum

In this study, effects of timed sequential exposure to various concentrations of chloroquine and its two metabolites (SA100387/050 B, SA 100487/053 B), quinine, hydroquinine and quinidine were monitored by morphological analyses, using synchronous cultures of Plasmodium falciparum. The trophozoites and schizonts were sensitive to chloroquine and its metabolites. However, quinine and two of its derivatives were lethal without particularly being stage-specific.     

Comparison of the effects of VVI versus DDD pacing on cardiac baroreflex function

INTRODUCTION: Conventional baroreceptor-heart rate (HR) reflex sensitivity cannot be examined in chronotropically incompetent patients or in pacemaker recipients. However, cardiac baroreceptor reflex sensitivity (BRS)-stroke volume (SV), which is closely and linearly correlated with BRS-HR, may be an alternative in that population. The aim of this study was to compare the BRS-SV in pacemaker recipients with a fixed HR paced in VVI versus DDD modes in the supine and upright positions. METHODS: The pacing mode was set randomly to DDD or VVI with complete atrial and/or ventricular capture, then crossed over to the alternate mode in 9 recipients of dual-chamber pacemakers with atrioventricular (AV) block. Beat-to-beat mean blood pressure and SV were measured in the supine and upright positions, using a tilt table. The BRS-SV, expressed in %/mmHg, was the ratio of low-frequency (LF) power to total power (TP) of SV variability, measured by spectral analysis of spontaneous variations in mean blood pressure and SV. RESULTS: BRS-SV was significantly lower in the VVI than in the DDD mode in the supine (37.2 +/- 26.7 vs 14.5 +/- 7.7%/mmHg) and upright (22.9 +/- 16.9 vs 10.6 +/- 6.6%/mmHg) positions (P < 0.05 for both comparisons). CONCLUSIONS: VVI pacing is adverse from the standpoint of cardiac autonomic baroreflex function. A decreased BRS-SV may be one of the factors involved in the hemodynamic intolerance associated with VVI pacing.     

Cardiopulmonary interactions in healthy children and children after simple cardiac surgery: the effects of positive and negative pressure ventilation

Objective—To investigate the effects of cuirass negative pressure ventilation on the cardiac output of a group of anaesthetised children after occlusion of an asymptomatic persistent arterial duct, and a group of paediatric patients in the early postoperative period following cardiopulmonary bypass.
Design—Prospective study.
Setting—The paediatric intensive care unit and catheter laboratory of a tertiary care centre.
Patients—16 mechanically ventilated children were studied: seven had undergone surgery for congenital heart disease, and nine cardiac catheterisation for transcatheter occlusion of an isolated asymptomatic persistent arterial duct.
Interventions—Cardiac output was measured using the direct Fick method during intermittent positive pressure ventilation and again after a short period of negative pressure ventilation. In five of the postoperative patients a third measurement was made following reinstitution of positive pressure ventilation.
Results—Negative pressure ventilation was delivered without complication, with no significant change in systemic arterial oxygen and carbon dioxide tension. The mixed venous saturation increased from 74% to 75.8% in the healthy children, and from 58.9% to 62.3% in the postoperative group. Negative pressure ventilation increased the cardiac index from 4.0 to 4.5 l/min/m² in the healthy children, and from 2.8 to 3.5 l/min/m² in the surgical group. The increase was significantly higher in the postoperative patients (28.1%) than the healthy children (10.8%).
Conclusions—While offering similar ventilatory efficiency to positive pressure ventilation, cuirass negative pressure ventilation led to a modest improvement in the cardiac output of healthy children, and to a greater increase in postoperative patients. There are important cardiopulmonary interactions in normal children and in children after cardiopulmonary bypass, and by having beneficial effects on these interactions, negative pressure ventilation has haemodynamic advantages over conventional positive pressure ventilation.

Keywords: cardiopulmonary interactions;  congenital heart disease;  ventilation;  children