Effects of Endurance Training at the Crossover Point in Women with Metabolic Syndrome

INTRODUCTION

On the basis of theoretical evidence, intensity at the crossover point (COP) of substrate utilization could be considered as potential exercise intensity for metabolic syndrome (MetS). This study aimed to examine the effects of a training program at COP on exercise capacity parameters in women with MetS and to compare two metabolic indices (COP and the maximal fat oxidation rate point LIPOXmax®) with ventilatory threshold (VT).

METHODS

Nineteen women with MetS volunteered to perform a 12-wk training program on a cycle ergometer, with intensity corresponding to COP. Pre- and posttraining values of anthropometric and exercise capacity parameters were compared to determine the effects of exercise training. The pre-post training change of COP, LIPOXmax®, and VT were also investigated.

RESULTS

After training, anthropometric parameters were significantly modified, with reduction of body mass (3.0% ± 3.0%, P < 0.001), fat mass (3.3% ± 3.4%, P < 0.001), and body mass index (3.2% ± 3.4%, P < 0.001). Exercise capacity was improved after the training program, with significant increase of maximal power output (25.0% ± 18.4%, P < 0.001) and maximal oxygen uptake (V˙O2max, 9.0% ± 11.2%; P < 0.01). Lastly, when expressed in terms of power output, COP, LIPOXmax®, and VT occurred at a similar exercise intensity, but the occurrence of these three indices is different when expressed in terms of oxygen uptake, HR, or RPE.

CONCLUSIONS

This study highlights the effectiveness of a 12-wk training program at COP to improve physical fitness in women with MetS. The relations between metabolic indices and VT in terms of power output highlight the determination of VT from a shorter maximal exercise as a useful method for determining metabolic indices in MetS.

A common variant in RAB27A gene is associated with fractional exhaled nitric oxide levels in adults

BACKGROUND

Exhaled nitric oxide (FeNO) is a biomarker for eosinophilic inflammation in the airways and for responsiveness to corticosteroids in asthmatics.

OBJECTIVE

We sought to identify in adults the genetic determinants of fractional exhaled nitric oxide (FeNO) levels and to assess whether environmental and disease-related factors influence these associations.

METHODS

We performed a genome-wide association study of FeNO through meta-analysis of two independent discovery samples of European ancestry: the outbred EGEA study (French Epidemiological study on the Genetics and Environment of Asthma, N = 610 adults) and the Hutterites (N = 601 adults), a founder population living on communal farms. Replication of main findings was assessed in adults from an isolated village in Sardinia (Talana study, N = 450). We then investigated the influence of asthma, atopy and tobacco smoke exposure on these genetic associations, and whether they were also associated with FeNO values in children of the EAGLE (EArly Genetics & Lifecourse Epidemiology, N = 8858) consortium.

RESULTS

We detected a common variant in RAB27A (rs2444043) associated with FeNO that reached the genome-wide significant level (P = 1.6 × 10(-7) ) in the combined discovery and replication adult data sets. This SNP belongs to member of RAS oncogene family (RAB27A) and was associated with an expression quantitative trait locus for RAB27A in lymphoblastoid cell lines from asthmatics. A second suggestive locus (rs2194437, P = 8.9 × 10(-7) ) located nearby the sodium/calcium exchanger 1 (SLC8A1) was mainly detected in atopic subjects and influenced by inhaled corticosteroid use. These two loci were not associated with childhood FeNO values.

CONCLUSIONS AND CLINICAL RELEVANCE

This study identified a common variant located in RAB27A gene influencing FeNO levels specifically in adults and with a biological relevance to the regulation of FeNO levels. This study provides new insight into the biological mechanisms underlying FeNO levels in adults.

Influence of physical fitness on antioxidant activity and malondialdehyde level in healthy older adults

The aim of this study was to investigate how physical fitness level could affect antioxidant activity and malondialdehyde (MDA) level at rest and in response to exhaustive exercise in healthy older adults. Fifty older adults (average age: 66.1 ± 3.8 years) were divided according to their physical fitness level into an unfit group (UG) (n = 15), a low fitness level group (LFG) (n = 18), and a high fitness level group (HFG) (n = 17). Fitness status was classified based on answers to a questionnaire about physical activity in the previous 12 months. Before and after an incremental cycle ergometer test to exhaustion, the following markers were assessed: superoxide dismutase (SOD), glutathione peroxidase (GPX), glutathione reductase, ascorbic acid, α-tocopherol, and MDA. At rest, SOD, GPX, and α-tocopherol activities were higher in the HFG (p < 0.05), whereas MDA level was lower in the LFG in comparison with the 2 other groups (p < 0.05). During the postexercise period, antioxidant activity increased only in the LFG and the HFG (GPX, SOD, and α-tocopherol). MDA level increased in all groups after the exercise (p < 0.05). In addition, MDA level was higher during the recovery period in the HFG as compared with the others groups. This study concluded that both low and high physical fitness levels help maintain better antioxidant defenses in older adults. However, a higher physical fitness level, rather than a lower physical fitness level, could increase lipid peroxidation.

Exhaled nitric oxide, nitrite/nitrate levels, allergy, rhinitis and asthma in the EGEA study

Although interest in biomarkers in the nitrate-nitrite-NO pathway has recently increased, associations between nitrite (NO2(-)) and nitrate (NO3(-)), and asthma, allergic sensitisation and rhinitis remain unclear. The study aimed to evaluate the associations between NO2(-)/NO3(-) and exhaled fraction of nitric oxide (FeNO) levels with asthma, allergic sensitisation and rhinitis. Plasma and exhaled breath condensate (EBC) NO2(-)/NO3(-) and FeNO levels were measured in 523 adults of the French Epidemiological study on Genetics and Environment of Asthma. Allergic sensitisation was defined by a positive skin prick test for at least one aeroallergen. Subjects were classified as non-sensitised, sensitised and as having allergic rhinitis. Plasma NO2 (-)/NO3(-) level was unrelated to any disease phenotypes. EBC NO2(-)/NO3(-) level was unrelated to any asthma phenotypes. EBC NO2(-)/NO3(-) and FeNO levels were correlated in sensitised subjects only (r = 0.21 ± 0.10, p=0.01). EBC NO2(-)/NO3(-) and FeNO levels were higher in sensitised than in non-sensitised subjects (adjusted geometric mean (95% CI): 2.36 (1.96-2.84) versus 1.72 (1.38-2.14) μmol per mg proteins, p=0.008; and 18.3 (16.7-20.0) versus 14.8 (13.3-16.5) ppb, p=0.0006, respectively), with gradual relationships from sensitised subjects to those with allergic rhinitis (p<0.0001). Results suggest that EBC NO2(-)/NO3(-) and FeNO levels may be considered as biological markers of intensity of allergic sensitisation and rhinitis.

Quantification of shape of flow-volume loop of healthy preschool children and preschool children with wheezing disorders

BACKGROUND

The earliest change associated with airflow obstruction in small airways is reflected in a concave shape on the maximum expiratory flow-volume loop (MEFVL). The shape of the MEFL changes with age but reference values for curvilinearity indices (CI) for preschool children have not been published. We aimed to describe the normal curvilinearity of healthy preschool MEFVL by CI (the β angle and the ratio of maximum expiratory flow when 50% of forced vital capacity remains to be expired/peak expiratory flow (MEF(50%) /PEF)) and to test their capacity in detecting concavity in preschool children with wheezing disorders.

METHODS

Spirometric data were obtained from 132 healthy preschool children and 171 3-to-5-year-old preschool children with wheezing disorders and reference values for CI calculated.

RESULTS

Mean (SD) β angle of healthy children was 203° (16°) and mean MEF(50%) /PEF of healthy children was 0.71 (0.12) indicating convexity of MEFVL, both decreased with increasing age (P = 10(-4) ). Children with wheezing disorders had lower z-score values of CI (P ≤ 10(-6) ) indicating more concave MEFVL. Among the two CI, MEF(50%) /PEF allowed for the best discrimination between healthy children and children with wheezing disorders (Wilks' lambda = 0.898, P = 10(-7) ).

CONCLUSION

These CI can detect and quantify the concavity of the descending limb of the MEFVL in preschool children with wheezing disorders, MEF(50%) /PEF having the highest sensitivity in detecting the concavity.

P. aeruginosa LPS stimulates calcium signaling and chloride secretion via CFTR in human bronchial epithelial cells

BACKGROUND

Pseudomonas aeruginosa airway infection is associated with a high mortality rate in cystic fibrosis. Lipopolysaccharide (LPS), a main constituent of the outer membrane of P. aeruginosa, is responsible for activation of innate immune response but its role on airway epithelium ion transport, is not well known. The aim of this study was to determine the role for P. aeruginosa LPS in modulating chloride secretion and intracellular calcium in the human bronchial epithelial cell line, 16HBE14o-.

METHODS

We used intracellular calcium imaging and short-circuit current measurement upon exposure of cells to P. aeruginosa LPS.

RESULTS

Apical LPS stimulated intracellular calcium release and calcium entry and enhanced chloride secretion. This latter effect was significantly inhibited by CFTR(inh)-172 and BAPTA-AM (intracellular Ca(2+) chelator).

CONCLUSIONS

Our data provides evidence for a new role of P. aeruginosa LPS in stimulating calcium entry and release and a subsequent chloride secretion via CFTR in human bronchial epithelium.

Interest of exhaled biomarkers in occupational asthma to latex: a case report

New methods for exploring pulmonary inflammation might be useful: measurements of exhaled nitric oxide (NO) and hydrogen peroxide (H(2)O(2)) in exhaled breath condensate (EBC). The authors describe the application and utility of these methods in a case report of pediatric nurse presenting an occupational asthma to latex. Despite compliance with avoidance measures, respiratory discomfort had worsened during work. Classical tests (spirometry, monitoring of peak expiratory flow) were not contributing to objectify the discomfort. Exhaled NO and H(2)O(2) in EBC increased immediately after work periods, compared with rest periods. Application of these new methods, at the same time, in workplace appears useful in the objective demonstration of a temporal relation between work and respiratory problems. The results allowed the occupational physician to transfer the patient to a new work station more appropriate for her respiratory health status.

Prediction of time to exhaustion in competitive cyclists from a perceptually based scale

Prediction of time to exhaustion in competitive cyclists from a perceptually based scale. We have tested the validity of the estimated time limit (ETL) scale to predict an exhaustion time (T(lim)) from values stemming from incremental and randomized constant workloads tests on a cycle ergometer. Twenty-five cyclists performed 1 continuous incremental test, 1 discontinuous test with randomized workloads, and 1 constant power output test at 90% of maximal aerobic power (MAP) to exhaustion. Estimated time limits at 90% MAP during the incremental test and the test with randomized workloads were calculated from exponential relationships between power and ETL using the same 4 workloads. Real measured T(lim) during the constant power output test was converted into ETL values (called measured ETL). The differences between the calculated and measured ETLs were examined. Estimated time limits calculated at 90% MAP during the incremental and randomized tests corresponded to 14 minutes 56 seconds and 10 minutes 14 seconds, whereas measured ETL was equal to 11 minutes 19 seconds ± 3 minutes 40 seconds. The results showed a nonsignificant difference between calculated and measured ETLs. However, the mean differences between the measured ETL values during the constant test performed at the same intensity were -1.3 ± 2.9 and 0.3 ± 3.0 for the incremental and the randomized constant workloads tests, respectively. Consequently, the use of ETL calculated at 90% MAP during the test with randomized constant workloads may be preferable to predict the accurate T(lim). Moreover, it would seem that high-level cyclists, who were more consciously attuned to their bodies and their own effort sense, were more accurate in their prediction than low-level cyclists. It is concluded that the randomized constant workloads test that is both shorter and less strenuous would be more convenient for high-level athletes.

Home telemonitoring (forced expiratory volume in 1 s) in children with severe asthma does not reduce exacerbations

Some children with severe asthma develop frequent exacerbations despite intensive treatment. We sought to assess the outcome (severe exacerbations and healthcare use, lung function, quality of life and maintenance treatment) of a strategy based on daily home spirometry with teletransmission to an expert medical centre and whether it differs from that of a conventional strategy. 50 children with severe uncontrolled asthma were enrolled in a 12-month prospective study and were randomised into two groups: 1) treatment managed with daily home spirometry and medical feedback (HM) and 2) conventional treatment (CT). The children's mean age was 10.9 yrs (95% confidence interval 10.2-11.6). 44 children completed the study (21 in the HM group and 23 in the CT group). The median number of severe exacerbations per patient was 2.0 (interquartile range 1.0-4.0) in the HM group and 3.0 (1.0-4.0) in the CT group (p=0.38 with adjustment for age). There were no significant differences between the two groups for unscheduled visits (HM 5.0 (3.0-7.0), CT 3.0 (2.0-7.0); p=0.30), lung function (pre-β(2)-agonist forced expiratory volume in 1 s (FEV(1)) p=0.13), Paediatric Asthma Quality of Life Questionnaire scores (p=0.61) and median daily dose of inhaled corticosteroids (p=0.86). A treatment strategy based on daily FEV(1) monitoring with medical feedback did not reduce severe asthma exacerbations.

Analysis of nitrogen oxides (NOx) in the exhaled breath condensate (EBC) of subjects with asthma as a complement to exhaled nitric oxide (FeNO) measurements: a cross-sectional study

Background

The study of pulmonary biomarkers with noninvasive methods, such as the analysis of exhaled breath condensate (EBC), provides a useful approach to the pathophysiology of asthma. Although many recent publications have applied such methods, numerous methodological pitfalls remain. The first stage of our study consisted of validating methods for the collection, storage and analysis of EBC; we next sought to clarify the utility of analysing nitrogen oxides (NOx) in the EBC of asthmatics, as a complement to measuring exhaled nitric oxide (FeNO).

Methods

This hospital-based cross-sectional study included 23 controls matched with 23 asthmatics. EBC and FeNO were performed and respiratory function measured. Intra-assay and intra-subject reproducibility were assessed for the analysis of NOx in the EBC of 10 healthy subjects.

Results

The intraclass correlation coefficient (ICC) was excellent for intra-assay reproducibility and was moderate for intra-subject reproducibility (Fermanian's classification). NOx was significantly higher in asthmatics (geometric mean [IQR] 14.4 μM [10.4 - 19.7] vs controls 9.9 μM [7.5 - 15.0]), as was FeNO (29.9 ppb [17.9 - 52.4] vs controls 9.6 ppb [8.4 - 14.2]). FeNO also increased significantly with asthma severity.

Conclusions

We validated the procedures for NOx analysis in EBC and confirmed the need for assays of other biomarkers to further our knowledge of the pathophysiologic processes of asthma and improve its treatment and control.

Usefulness of a new dialysis device adapted to small volume of red blood cells and its interest in epidemiology

OBJECTIVES

We checked the efficiency of a new dialysis device adapted to small volumes to remove glycerol from cryopreserved red blood cells.

DESIGN AND METHODS

Dialysis was performed on D-Tube96™ Dialyzer Mini device. In a preliminary trial, we measured the residual glycerol before, and 2, 4 and 24 h after dialysis. Glycerol and hemoglobin concentrations and antioxidant enzymes activities were measured in three samples with or without glycerolization/deglycerolization procedure. The mini dialysis was then applied to 96 samples from the French Epidemiological study on the Genetics and Environment of Asthma.

RESULTS

Ninety-two percent of glycerol was removed after 24 h of dialysis. Hemoglobin content and activities of superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase were recovered. No significant loss of volume was observed. Results obtained for the 96 samples perfectly fitted with reference values of our laboratory.

CONCLUSION

This new dialysis method seems to be particularly adapted for processing a large number of samples of RBCs cryoconserved in small volumes from epidemiological studies.

Cryptogenic haemoptysis in smokers: angiography and results of embolisation in 35 patients

The aim of the present study was to describe angiographic findings and embolisation results in smokers with haemoptysis. We retrospectively reviewed the clinical data and angiographic findings from 35 patients with smoking-related bronchopulmonary disease and no associated comorbidity, who were referred for embolisation for mild (n = 6), moderate (n = 14) and severe (n = 15) haemoptysis. Spirometric classification subdivided our population into: 16 patients with chronic bronchitis but no airflow limitation; and 19 patients with chronic obstructive pulmonary disease (COPD) (stage I: n = 12; stage II: n = 5; stage III: n = 2). Bronchoscopy depicted focal submucosal vascular abnormalities in three patients and only endobronchial inflammation in 32 (91%) patients. Bronchial artery angiography revealed moderate (n = 18) or severe (n = 10) hypervascularisation in 28 (80%) patients, and normal vascularisation in seven (20%). No statistically significant difference was observed between the angiographic findings and the severity of COPD, tobacco consumption or the amount of bleeding. Cessation of bleeding was obtained by embolisation in 29 out of the 34 technically successful procedures (85%), requiring surgery in three out of five patients with recurrence. Follow-up (mean duration 7 yrs) demonstrated no recurrence of bleeding in 32 (94%) out of 34 patients and excluded late endobronchial malignancy. Smokers with various stages of COPD severity may suffer from haemoptysis that is efficiently treatable by endovascular treatment.