Contribution of lung function in predicting distance covered in the 6-min walk test in obese Brazilian women.

Obesity affects the respiratory system through various mechanisms, including systemic inflammation and direct mechanical hindrance due to fat deposition in the chest and abdomen. In addition, changes in the neural control of respiration and increases in thoracic blood volume can promote abnormalities in lung function. Thus, determining relationships between the distance covered in the 6-min walk test (6MWT) and demographic and lung function variables may help us better understand the mechanisms involved in reduced functional exercise capacity in obesity. To explore the determinants of the 6-min walking distance (6MWD) and evaluate the influence of lung function on the distance covered, 263 obese Brazilian women performed the 6MWT and underwent spirometry and respiratory muscle strength measurement. The mean age was 41.8±11.1 years. The mean body mass index (BMI) was 45±8 kg/m2. The 6MWD showed correlations with height (r=0.319), age (r=-0.281), weight (r=-0.370), BMI (r=-0.561), forced vital capacity (FVC, r=0.443), expiratory peak flow (r=0.278), maximal inspiratory pressure (MIP, r=0.326), and maximal expiratory pressure (r=0.259), all with P<0.0001. In the stepwise forward regression analysis, BMI, FVC, age, and MIP were the independent predictive variables for 6MWD, explaining 41% of its variability. The reference equation including lung function was as follows: 6MWD (m) = 513.6 - (4.439 × BMIkg/m2) + (1.136 × FVC%predicted) - (1.048 × ageyrs) + (0.544 × MIP%predicted). Thus, the inclusion of lung function in a reference equation for 6MWD contributes to a better prediction of the distance covered in this population.

Contribution of lung function in predicting distance covered in the 6-min walk test in obese Brazilian women

Obesity affects the respiratory system through various mechanisms, including systemic inflammation and direct mechanical hindrance due to fat deposition in the chest and abdomen. In addition, changes in the neural control of respiration and increases in thoracic blood volume can promote abnormalities in lung function. Thus, determining relationships between the distance covered in the 6-min walk test (6MWT) and demographic and lung function variables may help us better understand the mechanisms involved in reduced functional exercise capacity in obesity. To explore the determinants of the 6-min walking distance (6MWD) and evaluate the influence of lung function on the distance covered, 263 obese Brazilian women performed the 6MWT and underwent spirometry and respiratory muscle strength measurement. The mean age was 41.8±11.1 years. The mean body mass index (BMI) was 45±8 kg/m2. The 6MWD showed correlations with height (r=0.319), age (r=-0.281), weight (r=-0.370), BMI (r=-0.561), forced vital capacity (FVC, r=0.443), expiratory peak flow (r=0.278), maximal inspiratory pressure (MIP, r=0.326), and maximal expiratory pressure (r=0.259), all with P<0.0001. In the stepwise forward regression analysis, BMI, FVC, age, and MIP were the independent predictive variables for 6MWD, explaining 41% of its variability. The reference equation including lung function was as follows: 6MWD (m) = 513.6 - (4.439 × BMIkg/m2) + (1.136 × FVC%predicted) - (1.048 × ageyrs) + (0.544 × MIP%predicted). Thus, the inclusion of lung function in a reference equation for 6MWD contributes to a better prediction of the distance covered in this population.

[Correlation between pulmonary function, posture, and body composition in patients with asthma]. / Correlação entre função pulmonar, postura e composição corporal em pacientes com asma.

AIM: Asthma may result in postural disorders due to increased activity of accessory respiratory muscles and hyperinflation. Our primary objective was to assess the correlation between pulmonary function and posture in adult patients with asthma. Secondarily, we aimed to study the correlation between body composition and body posture in this group of patients. METHOD: This was a cross-sectional study including 34 patients with asthma who were subjected to postural assessment (photogrammetry), pulmonary function testing (spirometry, whole-body plethysmography, diffusing capacity for carbon monoxide, and respiratory muscle strength), and body composition estimation by means of bioelectrical impedance. RESULTS: Most patients were female (70.6%) with a median age of 32.5 years (range: 23-42 years old). We found a significant correlation between horizontal alignment of head (anterior view) and the ratio of forced expiratory volume in 1 second to forced vital capacity (FEV1/FVC; ρ=-0,37; P=.03), total lung capacity (TLC; ρ=0,42; P=.01), and residual volume (RV; ρ=0,45; P<.001). Bronchial obstruction and respiratory muscle strength variables also correlated with postural assessment measures on the right and left lateral views. Both body mass index and the percentage of fat mass correlated with horizontal alignment of head, horizontal alignment of the pelvis, and the frontal angle of the lower limbs. CONCLUSION: Adult patients with asthma exhibit specific postural disorders that correlate with pulmonary function and body composition. The assessment of postural variables may provide a better pulmonary rehabilitation approach for these patients.

Is the type of chronic pulmonary infection a determinant of lung function outcomes in adult patients with cystic fibrosis?

BACKGROUND AND AIM: Lung function abnormalities are the main factors responsible for the high mortality of cystic fibrosis (CF) patients. It is not yet clear whether Burkholderia cepacia infection causes more pronounced loss of lung function than pseudomonas aeruginosa infection. Our primary objective was to compare the lung function of adult CF patients with different chronic pulmonary infections. Our second objective was to compare the microbiology using patients' genetic status. METHODS: Fifty-two adult CF patients were divided into 3 groups according to their chronic pulmonary infection profile. All subjects underwent clinical evaluation, pulmonary function tests (PFT) and genetic analysis. RESULTS: The PFT parameters of chronically infected patients were significantly different from those of subjects without pulmonary infection (p < 0.0001). FVC was significantly more altered in patients infected with B. cepacia complex (p < 0.0001); in contrast, FEF25-75% was significantly more altered in patients with P. aeruginosa infection (p < 0.0001). In the groups with chronic P. aeruginosa infection and chronic B. cepacia complex infection, 58.1% and 10% of patients were homozygous for AF508, respectively. In addition to chronic infections, pancreatic insufficiency was also associated with lung function deterioration. CONCLUSION: Chronic pulmonary infection and pancreatic insufficiency are critical processes in lung function deterioration in adult CF patients. Although chronic B. cepacia complex infection causes a more pronounced lung volume reduction, chronic P. aeruginosa infection causes a more pronounced obstruction of small airways. Our results also suggest that deltaF508-homozygous patients are more susceptible to chronic P. aeruginosa infection.

Low expression of antigen-presenting and costimulatory molecules by lung cells from tuberculosis patients

Costimulatory and antigen-presenting molecules are essential to the initiation of T cell immunity to mycobacteria. The present study analyzed by immunocytochemistry, using monoclonal antibodies and alkaline phosphatase-anti-alkaline phosphatase method, the frequency of costimulatory (CD86, CD40, CD40L, CD28, and CD152) and antigen-presenting (MHC class II and CD1) molecules expression on human lung cells recovered by sputum induction from tuberculosis (TB) patients (N = 22) and non-TB controls (N = 17). TB cases showed a statistically significant lower percentage of HLA-DR+ cells than control subjects (21.9 ± 4.2 vs 50.0 ± 7.2 percent, P < 0.001), even though similar proportions of TB cases (18/22) and control subjects (16/17, P = 0.36) had HLA-DR-positive-stained cells. In addition, fewer TB cases (10/22) compared to control subjects (16/17) possessed CD86-expressing cells (P = 0.04; OR: 0.05; 95 percentCI = 0.00-0.51), and TB cases expressed a lower percentage of CD86+ cells (P = 0.04). Moreover, TB patients with clinically limited disease (£1 lobe) on chest X-ray exhibited a lower percentage of CD86-bearing cells compared to patients with more extensive lung disease (>1 lobe) (P = 0.02). The lower expression by lung cells from TB patients of HLA-DR and CD86, molecules involved in antigen presentation and activation of T cells, may minimize T cell recognition of Mycobacterium tuberculosis, fostering an immune dysfunctional state and active TB.

Low expression of antigen-presenting and costimulatory molecules by lung cells from tuberculosis patients.

Costimulatory and antigen-presenting molecules are essential to the initiation of T cell immunity to mycobacteria. The present study analyzed by immunocytochemistry, using monoclonal antibodies and alkaline phosphatase-anti-alkaline phosphatase method, the frequency of costimulatory (CD86, CD40, CD40L, CD28, and CD152) and antigen-presenting (MHC class II and CD1) molecules expression on human lung cells recovered by sputum induction from tuberculosis (TB) patients (N = 22) and non-TB controls (N = 17). TB cases showed a statistically significant lower percentage of HLA-DR+ cells than control subjects (21.9 +/- 4.2 vs 50.0 +/- 7.2%, P < 0.001), even though similar proportions of TB cases (18/22) and control subjects (16/17, P = 0.36) had HLA-DR-positive-stained cells. In addition, fewer TB cases (10/22) compared to control subjects (16/17) possessed CD86-expressing cells (P = 0.04; OR: 0.05; 95%CI = 0.00-0.51), and TB cases expressed a lower percentage of CD86+ cells (P = 0.04). Moreover, TB patients with clinically limited disease ( pound1 lobe) on chest X-ray exhibited a lower percentage of CD86-bearing cells compared to patients with more extensive lung disease (>1 lobe) (P = 0.02). The lower expression by lung cells from TB patients of HLA-DR and CD86, molecules involved in antigen presentation and activation of T cells, may minimize T cell recognition of Mycobacterium tuberculosis, fostering an immune dysfunctional state and active TB.