Activity,Severity and Impact of Respiratory Disease in Primary Antibody Deficiency Syndromes

Purpose

Some patients with primary antibody deficiency (PAD) syndromes develop bronchiectasis. In immunocompetent patients with bronchiectasis, key clinico-pathophysiological relationships exist between exacerbation frequency, lung function, health-status, infection and inflammation. It is not known whether such relationships are present in PAD. It is also not known how local and systemic inflammation in PAD compares with that in immunocompetent (non-PAD) bronchiectasis patients.

Method

We assessed symptoms, exacerbation frequency, health-status, lung function, CT, airway and systemic inflammation and infection in 33 PAD patients and 20 immunocompetent controls with bronchiectasis.

Results

Despite less severe airflow obstruction, PAD patients had similar health-status impairment and greater airway (sputum log₁₀ IL-6 2.71 vs. 1.81 pg/ml, p?=?0.001) and greater systemic inflammation than immunocompetent bronchiectasis controls (serum log₁₀ CRP 0.77 vs. 0.36 mg/l, p?=?0.001). In PAD, cross-sectional markers of disease severity (CT and lung function) did not relate to inflammatory markers of disease activity, however there was a relationship between FEV₁ decline rate and systemic inflammation (IL-6; r?=?0.42, p?=?0.036) and the magnitude of the systemic inflammatory response was related to that in the airway. Correlation between generic SF36 and respiratory SGRQ questionnaires (r?=??0.79, p?<?0.001) suggests that much health-status impairment in PAD relates to respiratory involvement. Health-status was associated with dyspnoea (rho?=?0.77, p?<?0.001), respiratory infection frequency (rho?=?0.48, p?=?0.016), lung function (FEV₁: r?=??0.60, p?=?0.001) and rate of lung function decline (r?=?0.41, p?=?0.047).

Conclusion

The major findings of this analysis are that in patients with PAD, cross-sectional markers of disease severity such as lung function and CT extent of disease do not reflect disease activity as assessed by airway and systemic inflammation. In addition, there is a relationship between the rate of progression of lung disease and the severity of the systemic inflammatory response which itself is related to that in the airway. Much of the quality of life impact in PAD relates to respiratory involvement, specifically the severity of airflow obstruction, respiratory exacerbation frequency and dyspnoea. Finally, patients with PAD had greater airway and systemic inflammation than a control population with non-PAD bronchiectasis which may suggest a dysregulated airway immune response.     

Associations of objectively measured sedentary behavior,light activity,and markers of cardiometabolic health in young women

Purpose

To investigate the associations among objectively measured sedentary behavior, light physical activity, and markers of cardiometabolic health in young women.

Methods

Cardiovascular disease risk factors, homeostasis model assessment for insulin resistance (HOMA-IR), lipid accumulation product, and inflammatory markers were measured in 50 young, adult women. Accelerometers were worn over 7 days to assess sedentary time (<150 counts min^?1), light physical activity (150–2,689 counts min^?1), and moderate-to-vigorous physical activity (MVPA; ≥2,690 counts min^?1). Multivariate regression examined independent associations of sedentary behavior and light physical activity with cardiometabolic health. Covariates included MVPA, cardiorespiratory fitness (VO_2peak) and body mass, and body composition.

Results

Sedentary behavior was associated with triglycerides (p = 0.03) and lipid accumulation product (p = 0.02) independent of MVPA. These associations were attenuated by VO_2peak and body mass or body composition (p ≥ 0.05). Light physical activity was independently associated with triglycerides and lipid accumulation product after adjustment for all covariates (p < 0.05). The association between light physical activity and HOMA-IR was independent of MVPA (p = 0.02) but was attenuated by VO_2peak and body mass or body composition (p > 0.05).

Conclusions

Sedentary behavior and light physical activity were independently associated with markers of cardiometabolic health in young, adult women. Our data suggest that VO_2peak and body composition may be important mediators of these associations. Decreasing sedentary behavior and increasing light physical activity may be important for maintaining cardiometabolic health in young, adult women.     

Exhaled breath condensate pH in patients with cystic fibrosis

Objective and design

Exhaled breath condensate (EBC) pH has been proposed as a useful, non-invasive marker of airway inflammation in pulmonary diseases. In this study we tested whether cystic fibrosis (CF) is associated with acidification of EBC, when pH is assessed by the CO₂ gas standardization method.

Methods

EBC was collected using two different devices (EcoScreen and R-Tube) in 46 stable CF patients during routine clinical visits and in 28 healthy controls.

Results

Mean EBC pH in CF patients and in healthy controls was similar (EcoScreen: CF patients: 6.38?±?0.03 versus controls: 6.39?±?0.03, p?=?0.699; R-tube: CF patients: 5.94?±?0.04 versus controls: 6.02?±?0.03, p?=?0.159). Inflammatory cell counts in spontaneously expectorated sputum obtained in a subset of patients (n?=?20) showed no correlation with pH values. EBC samples collected with the R-tube were more acidic than those collected with the EcoScreen device (p?Conclusions Our data suggest that EBC pH does not discriminate between healthy controls and those with CF disease indicating that the clinical applicability of EBC pH measurements for assessing airway inflammation in CF is limited.     

Latent cytomegalovirus infection and innate immune function following a 75 km cycling time trial

Purpose

This study compared the acute immune response, inflammation, and lipid peroxidation to a 75 km cycling time trial in male athletes testing positive or negative for latent cytomegalovirus (CMV) infection.

Design

Trained cyclists (N = 20) were tested for CMV serostatus, and cycled 75 km on a mountainous course using indoor trainers with continuous workload monitoring. Pre-, post-, and 1 h post-exercise blood samples were analyzed for total blood leukocyte counts, blood granulocyte (GR) and monocyte (MO) phagocytosis (PHAG) and oxidative burst activity (OBA), four plasma cytokines, and plasma F₂-isoprostanes.

Results

Forty percent of the subjects tested positive for CMV. No differences in subject characteristics were found between CMV_pos and CMV_neg groups. Mean power (57.3 ± 1.6, 59.4 ± 1.8 % maximal Watts, p = 0.803), heart rate (87.0 ± 1.0, 86.5 ± 1.3 % maximal heart rate, p = 0.376), and total time (2.56 ± 0.08, 2.60 ± 0.08 h, p = 0.744) to complete the 75 km cycling time trial did not differ between CMV_pos and CMV_neg groups. Whereas exercise induced significant changes in total blood leukocyte counts, GR and MO-PHAG, four plasma cytokines, and plasma F₂-isoprostanes (p < 0.05, ω² > 0.03), these exercise-induced changes did not differ between CMV_pos and CMV_neg groups (p > 0.05, ω² < 0.01).

Conclusions

CMV serostatus does not appear to influence these innate immune responses or markers of inflammation and lipid peroxidation in response to a single bout of heavy exertion.     

Faster \dot{V}{\text{O}}_{ 2} kinetics after eccentric contractions is explained by better matching of O2 delivery to O2 utilization

Purpose

This study examined the impact of eccentric exercise-induced muscle damage on the rate of adjustment in muscle deoxygenation and pulmonary O₂ uptake ( \(\dot{V}{\text{O}}_{{2{\text{p}}}}\) ) kinetics during moderate exercise.

Methods

Fourteen males (25 ± 3 year; mean ± SD) completed three step transitions to 90 % θ_L before (Pre), 24 h (Post24) and 48 h after (Post48) eccentric exercise (100 eccentric leg-press repetitions with a load corresponding to 110 % of the participant’s concentric 1RM). Participants were separated into two groups: phase II \(\dot{V}{\text{O}}_{{2{\text{p}}}}\) time constant (τ \(\dot{V}{\text{O}}_{{2{\text{p}}}}\) ) ≤ 25 s (fast group; n = 7) or τ \(\dot{V}{\text{O}}_{{2{\text{p}}}}\)  > 25 s (slow group; n = 7). \(\dot{V}{\text{O}}_{{2{\text{p}}}}\) and [HHb] responses were modeled as a mono-exponential.

Results

In both groups, isometric peak torque (0°/s) at Post24 was decreased compared to Pre (p < 0.05) and remained depressed at Post48 (p < 0.05). τ \(\dot{V}{\text{O}}_{{2{\text{p}}}}\) was designed to be different (p < 0.05) at Pre between the Fast (τ \(\dot{V}{\text{O}}_{{2{\text{p}}}}\) ; 19 ± 4 s) and Slow (32 ± 6 s) groups. There were no differences among time points (τ \(\dot{V}{\text{O}}_{{2{\text{p}}}}\) : Pre, 19 ± 4 s; Post24, 22 ± 3 s; Post48, 20 ± 4 s) in the Fast group. In Slow, there was a speeding (p < 0.05) from the Pre (32 ± 6 s) to the Post24 (25 ± 6) but not Post48 (31 ± 6), resulting in no difference (p > 0.05) between groups at Post24. This reduction of τ \(\dot{V}{\text{O}}_{{2{\text{p}}}} \,\) was concomitant with the abolishment (p < 0.05) of an overshoot in the [HHb]/ \(\dot{V}{\text{O}}_{{2{\text{p}}}}\) ratio.

Conclusion

We propose that the sped \(\dot{V}{\text{O}}_{{2{\text{p}}}}\) kinetics observed in the Slow group coupled with an improved [HHb]/ \(\dot{V}{\text{O}}_{{2{\text{p}}}}\) ratio suggest a better matching of local muscle O₂ delivery to O₂ utilization following eccentric contractions.     

Effects of Preoperative Short Term Use of Atorvastatin on Endothelial Progenitor Cells after Coronary Surgery: A Randomized, Controlled Trial

Objectives

We investigated the effects of short-term use of atorvastatin on CD34+/VEGF-R2+/CD133+/CD45- endothelial progenitor cell (EPC) count after on-pump coronary artery bypass surgery (CABG).

Methods

Between Feb-2010 and May-2010, we randomly assigned, in a placebo-controlled, double-blind study, 60 consecutive patients who underwent isolated, first-time CABG to receive either 14-day atorvastatin (40 mg/day) or placebo preoperatively. Urgent CABG and recent myocardial infarction were excluded. EPCs were quantified (cells/μl) by flow cytometric phenotyping obtained from venous blood samples collected preoperatively (T₁), 6-hours (T₂), and on the 5th day postoperatively (T₃). Levels of markers of inflammation and serum cardiac troponin I were also measured preoperatively and daily until day-5 after surgery.

Results

There were no differences in baseline risk factors including cholesterol profiles, and EuroSCORES between the groups. The composite primary end-point, favored statin group with higher amount of circulating, early EPC count (cells/μl) at all time points compared with placebo (T₁, 2.30?±?0.02 versus 1.58?±?0.03, p?2, 5.00?±?0.06 versus 2.19?±?0.06, p?3, 3.03?±?0.08 versus 1.78?±?0.02, p?1, 0.8?±?0.1 versus 2.2?±?1.5, p?2, 72.9?±?3.2 versus 96.0?±?3.6, p?3, 4.3?±?1.2 versus 11.4?±?4.1, p?p?=?0.02).

Conclusions

Short-term atorvastatin use increases circulating early EPCs both pre- and post-operatively and is associated with better preservation of sinus rhythm and reduced hsCRP levels. (ClinicalTrials.gov number, NCT01096875)     

The validity of the Moxus Modular metabolic system during incremental exercise tests: impacts on detection of small changes in oxygen consumption

Purpose

We investigated the accuracy of the Moxus Modular Metabolic System (MOXUS) against the Douglas Bag Method (DBM) during high-intensity exercise, and whether the two methods agreed when detecting small changes in $\dot{V}{\text{O}}_{2}$ between two consecutive workloads ( $\Delta {\dot{{V}}\text{O}}_{ 2}$ ).

Methods

Twelve trained male runners performed two maximal incremental running tests while gas exchange was analyzed simultaneously by the two systems using a serial setup for four consecutive intervals of 30 s on each test. Comparisons between methods were performed for $\dot{V}{\text{O}}_{2}$ , ${\dot{{V}}}_{\text{E}}$ , fractions of expired O₂ (FeO₂) and CO₂ (FeCO₂) and $\Delta {\dot{{V}}\text{O}}_{ 2}$ .

Results

The MOXUS produced significant higher (mean ± SD, n = 54) readings for $\dot{V}{\text{O}}_{2}$ (80 ± 200 mL min^?1, p = 0.005) and ${\dot{{V}}}_{\text{E}}$ (2.9 ± 4.2 L min^?1, p < 0.0001), but not FeO₂ (?0.01 ± 0.09). Log-transformed 95 % limits of agreement for readings between methods were 94–110 % for $\dot{V}{\text{O}}_{2}$ , 97–108 % for $\dot{V}_{\text{E}}$ and 99–101 % for FeO₂. $\Delta \dot{V}{\text{O}}_{2}$ for two consecutive measurements was not different between systems (120 ± 110 vs. 90 ± 190 mL min^?1 for MOXUS and DBM, respectively, p = 0.26), but agreement between methods was very low (r = 0.25, p = 0.12).

Discussion

Although it was tested during high-intensity exercise and short sampling intervals, the MOXUS performed within the acceptable range of accuracy reported for automated analyzers. Most of the differences between equipments were due to differences in $\dot{V}_{\text{E}}$ . Detecting small changes in $\dot{V}{\text{O}}_{2}$ during an incremental test with small changes in workload, however, might be beyond the equipment’s accuracy.     

Urinary trypsin inhibitor suppresses excessive generation of superoxide anion radical, systemic inflammation, oxidative stress, and endothelial injury in endotoxemic rats

Objective and design

The protective effects of ulinastatin, a human urinary trypsin inhibitor (UTI), against superoxide radical (O ₂ ^?· ) generation, systemic inflammation, lipid peroxidation, and endothelial injury were investigated in endotoxemic rats.

Materials and treatment

Twenty-one Wistar rats were allocated to a control group, a UTI group, and a sham group. A bolus of lipopolysaccharide (LPS; 3 μg/g) was administered intravenously to the control group, a bolus of LPS and UTI (5 U/g) to the UTI group, and a bolus of saline to the sham group.

Methods

The O ₂ ^?· generated was measured as the current in the right atrium using an electrochemical O ₂ ^?· sensor. Plasma nitrite, high mobility group box 1 (HMGB1), tumor necrosis factor (TNF)-α, inteleukin (IL)-6, malondialdehyde, and soluble intercellular adhesion molecule-1 (sICAM-1) were measured 360 min after LPS administration.

Results

The O ₂ ^?· current increased in the control group and was significantly attenuated in the UTI group after 55 min (P < 0.05 at 55–60 min, P < 0.01 at 65–360 min). Plasma nitrite, HMGB1, TNF-α, IL-6, malondialdehyde, and sICAM-1 were attenuated in the UTI group.

Conclusions

UTI suppressed excessive O ₂ ^?· generation, systemic inflammation, lipid peroxidation, and endothelial injury in endotoxemic rats.     

Combined caffeine and carbohydrate ingestion: effects on nocturnal sleep and exercise performance in athletes

Purpose

In athletes, caffeine use is common although its effects on sleep have not been widely studied. This randomised, double-blind, placebo-controlled crossover trial investigated the effects of late-afternoon caffeine and carbohydrate-electrolyte (CEB) co-ingestion on cycling performance and nocturnal sleep.

Methods

Six male cyclists/triathletes (age 27.5 ± 6.9 years) completed an afternoon training session (TS; cycling 80 min; 65 % VO_2max) followed by a 5 kJ kg^?1 cycling time trial (TT). Caffeine (split dose 2 × 3 mg kg^?1) or placebo was administered 1 h prior and 40 min into the TS. A 7.4 % CEB (3 ml kg^?1 every 15 min) was administered during the TS, followed 30 min after by a standardised evening meal. Participants retired at their usual bedtime and indices of sleep duration and quality were monitored via polysomnography. Data: mean ± SD.

Results

All participants performed better in the caffeine TT (caffeine 19.7 ± 3.3; placebo 20.5 ± 3.5 min; p = 0.006), while ratings of perceived exertion (caffeine 12.0 ± 0.6; placebo 12.9 ± 0.7; p = 0.004) and heart rate (caffeine 175 ± 6; placebo 167 ± 11 bpm; p = 0.085) were lower in the caffeine TS. Caffeine intake induced significant disruptions to a number of sleep indices including increased sleep onset latency (caffeine 51.1 ± 34.7; placebo 10.2 ± 4.2 min; p = 0.028) and decreased sleep efficiency (caffeine 76.1 ± 19.6; placebo 91.5 ± 4.2 %; p = 0.028), rapid eye movement sleep (caffeine 62.1 ± 19.6; placebo 85.8 ± 24.7 min; p = 0.028) and total sleep time (caffeine 391 ± 97; placebo 464 ± 49 min; p = 0.028).

Conclusions

This study supports a performance-enhancing effect of caffeine, although athletes (especially those using caffeine for late-afternoon/evening training and competition) should consider its deleterious effects on sleep.     

Serum amyloid A, phospholipase A2-IIA and C-reactive protein as inflammatory biomarkers for prostate diseases

Introduction

Serum amyloid A (SAA), secreted group IIA phospholipase A₂ (sPLA₂-IIA), and C-reactive protein (CRP) are acute-phase proteins whose serum concentrations increase not only during inflammatory disorders, but also in the course of malignant diseases.

Materials and methods

In this study we analyzed serum levels of these inflammatory markers along with prostate-specific antigens (PSA) in patients with benign prostatic hyperplasia (BPH, n = 55), localized prostate cancers (PCa, n = 55), and metastatic prostate cancers (mPCa, n = 27) using immunological assays.

Results

We found that in comparison to healthy individuals (n = 55), patients with BPH, PCa and mPCa have elevated serum levels of SAA, sPLA₂-IIA, and CRP, in addition to elevated levels of PSA. Significant differences with respect to inflammatory biomarkers were found between localized and metastatic PCa (p < 0.001), suggesting a prognostic value of these parameters. In addition, serum concentrations of SAA and sPLA₂-IIA positively correlate with CRP in BPH patients (p < 0.05) and in patients with PCa and mPCa (p < 0.001), but not with PSA levels, Gleason score, or tumor stage, emphasizing a role of SAA and sPLA₂-IIA as circulating biomarkers of inflammation rather than of neoplastic transformation. In contrast to PSA, which differed significantly between BPH and localized PCa patients (p < 0.01), such a difference was not found for SAA, sPLA₂-IIA, and CRP. In order to elucidate whether the elevated levels of SAA and sPLA₂-IIA can be caused by cancer cell-associated synthesis, in vitro studies were performed. These analyses demonstrated the expression of SAA and sPLA₂-IIA in LNCaP and PC-3 prostate cell lines, which can be further upregulated by pro-inflammatory cytokines in a cell type-dependent manner. This might suggest that, in addition to the hepatic origin, SAA and sPLA₂-IIA can also be synthesized and secreted by prostatic cancer tissue itself.

Conclusion

The results of the present study emphasize the utility of SAA, sPLA₂-IIA, and CRP as circulating biomarkers of inflammation during BPH development and PCa progression.     

Influence of post-exercise hypoxic exposure on hepcidin response in athletes

Purpose

To assess the influence of a simulated altitude exposure (~2,900 m above sea level) for a 3 h recovery period following intense interval running on post-exercise inflammation, serum iron, ferritin, erythropoietin, and hepcidin response.

Methods

In a cross-over design, ten well-trained male endurance athletes completed two 8 × 3 min interval running sessions at 85 % of their maximal aerobic velocity on a motorized treadmill, before being randomly assigned to either a hypoxic (HYP: F _IO₂ ~0.1513) or a normoxic (NORM: F _IO₂ 0.2093) 3 h recovery period. Venous blood was collected pre- and immediately post-exercise, and after 3 and 24 h of recovery. Blood was analyzed for interleukin-6, serum iron, ferritin, erythropoietin, and hepcidin.

Results

Interleukin-6 was significantly elevated (p < 0.01) immediately post-exercise compared to baseline (NORM: 1.08 ± 0.061 to 3.12 ± 1.80) (HYP: 1.32 ± 0.86 to 2.99 ± 2.02), but was not different between conditions. Hepcidin levels were significantly elevated (p < 0.01) at 3 h post-exercise for both conditions when compared to baseline (NORM: 3.25 ± 1.23 to 7.40 ± 4.00) (HYP: 3.24 ± 1.94 to 5.42 ± 3.20), but were significantly lower (p < 0.05) in the HYP trial compared to NORM. No significant differences existed between HYP and NORM for erythropoietin, serum iron, or ferritin.

Conclusion

Simulated altitude exposure (~2,900 m) for 3 h following intense interval running attenuates the peak hepcidin levels recorded at 3 h post-exercise. Consequently, a hypoxic recovery after exercise may be useful for athletes with compromised iron status to potentially increase acute dietary iron absorption.     

Dried blood spot omega-3 and omega-6 long chain polyunsaturated fatty acid levels in 7–9 year old Zimbabwean children: a cross sectional study

Background

Omega-3 long chain-polyunsaturated fatty acids (LC-PUFAs)–docosahexaenoic acid (DHA), docosapentaenoic acid (DPA) and eicosapentaenoic acid (EPA)– and omega-6 LC-PUFA arachidonic acid (ARA), are essential for optimum physical and mental development in children. Prior to this study, the blood omega-3 LC-PUFA levels were unknown in Zimbabwean children, particularly in those aged 7–9 years, despite the documented benefits of LC-PUFAs. Documentation of the LC-PUFA levels in this age group would help determine whether interventions, such as fortification, are necessary. This study aimed to determine dried whole blood spot omega-3 and omega-6 LC-PUFA levels and LC-PUFA reference intervals among a selected group of Zimbabwean children aged 7–9 years old.

Methods

We conducted a cross sectional study from September 2011 to August 2012 on a cohort of peri-urban, Zimbabwean children aged 7–9 years. The children were born to mothers enrolled at late pregnancy into an HIV prevention program between 2002 and 2004. Dried whole blood spots were sampled on butylated hydroxytoluene antioxidant impregnated filter papers and dried. LC-PUFAs were quantified using gas liquid chromatography. Differences in LC-PUFAs between groups were compared using the Kruskal Wallis test and reference intervals determined using non-parametric statistical methods.

Results

LC-PUFAs levels were determined in 297 Zimbabwean children of whom 170 (57.2 %) were girls. The study determined that LC-PUFAs (wt/wt) ranges were EPA 0.06–0.55 %, DPA 0.38–1.98 %, DHA 1.13–3.52 %, ARA 5.58–14.64 % and ARA: EPA ratio 15.47–1633.33. Sixteen participants had omega-3 LC-PUFAs levels below the determined reference intervals, while 18 had higher omega-6 LC-PUFAs. The study did not show gender differences in omega-3 and omega-6 LC-PUFAs levels (all p?>?0.05). EPA was significantly higher in the 8 year age group compared to those aged 7 and 9 years (median; 0.20 vs 0.17 vs 0.18, respectively, p?=?0.049). ARA: EPA ratio was significantly higher in the 7 year age group compared to those aged 8 and 9 years (median; 64.38 vs 56.43 vs 55.87 respectively, p?=?0.014).

Conclusions

In this cohort of children, lower EPA levels and higher ARA: EPA ratios were observed compared to those reported in apparently healthy children elsewhere. The high ARA: EPA ratios might increase the vulnerability of these children to inflammatory pathologies. Identification and incorporation into diet of locally produced foodstuffs rich in omega-3 LC-PUFAs is recommended as well as advocating for dietary supplementation with omega-3 fish oils and algae based oils.

     

Influence of exercise intensity on respiratory muscle fatigue and brachial artery blood flow during cycling exercise

Purpose

During high intensity exercise, both respiratory muscle fatigue and cardiovascular reflexes occur; however, it is not known how inactive limb blood flow is influenced. The purpose of this study was to determine the influence of moderate and high exercise intensity on respiratory muscle fatigue and inactive limb muscle and cutaneous blood flow during exercise.

Methods

Twelve men cycled at 70 and 85 % \(\dot{V}{\text{O}}_{{ 2_{ {\rm max} } }}\) for 20 min. Subjects also performed a second 85 % \(\dot{V}{\text{O}}_{{ 2_{ {\rm max} } }}\) test after ingesting 1,800 mg of N-acetylcysteine (NAC), which has been shown to reduce respiratory muscle fatigue (RMF). Maximum inspiratory pressures (P _Imax), brachial artery blood flow (BABF), cutaneous vascular conductance (CVC), and mean arterial pressure were measured at rest and during exercise.

Results

Significant RMF occurred with 85 % \(\dot{V}{\text{O}}_{{ 2_{ {\rm max} } }}\) (P _Imax, ?12.8 ± 9.8 %), but not with 70 % \(\dot{V}{\text{O}}_{{ 2_{ {\rm max} } }}\) (P _Imax, ?5.0 ± 5.9 %). BABF and BA vascular conductance were significantly lower at end exercise of the 85 % \(\dot{V}{\text{O}}_{{ 2_{ {\rm max} } }}\) test compared to the 70 % \(\dot{V}{\text{O}}_{{ 2_{ {\rm max} } }}\) test. CVC during exercise was not different (p > 0.05) between trials. With NAC, RMF was reduced (p < 0.05) and BABF was significantly higher (~30 %) compared to 85 % \(\dot{V}{\text{O}}_{{ 2_{ {\rm max} } }}\) (p < 0.05).

Conclusions

These data suggest that heavy whole-body exercise at 85 % \(\dot{V}{\text{O}}_{{ 2_{ {\rm max} } }}\) leads to RMF, decreases in inactive arm blood flow, and vascular conductance, but not cutaneous blood flow.     

Acute hypoxic exercise does not alter post-exercise iron metabolism in moderately trained endurance athletes

Purpose

This study measured the influence of acute hypoxic exercise on Interleukin-6 (IL-6), hepcidin, and iron biomarkers in athletes.

Methods

In a repeated measures design, 13 moderately trained endurance athletes performed 5 × 4 min intervals at 90 % of their peak oxygen consumption velocity (vVO_2peak) in both normoxic [NORM, fraction of inspired oxygen (F _IO₂) = 0.2093, 15.3 ± 1.7 km h^?1] and simulated hypoxic (HYP, F _IO₂ = 0.1450, 13.2 ± 1.5 km h^?1) conditions. Venous blood samples were obtained pre-, post-, and 3 h post-exercise, and analysed for serum hepcidin, IL-6, ferritin, iron, soluble transferrin receptor (sTfR), and transferrin saturation.

Results

Peak heart rate was significantly lower in HYP compared with NORM (p = 0.01); however, the rating of perceived exertion was similar between trials (p = 0.24). Ferritin (p = 0.02), transferrin (p = 0.03), and IL-6 (p = 0.01) significantly increased immediately post-exercise in both conditions, but returned to baseline 3 h later. Hepcidin levels significantly increased in both conditions 3 h post-exercise (p = 0.05), with no significant differences between trials. A significant treatment effect was observed between trials for sTfR (p = 0.01), but not iron and transferrin saturation.

Conclusion

Acute exercise in hypoxia did not influence post-exercise IL-6 production, hepcidin activity or iron metabolism compared with exercise at the same relative intensity in normoxia. Hence, acute exercise performed at the same relative intensity in hypoxia poses no further risk to an athlete’s iron status, as compared with exercise in normoxia.     

The effect of β-alanine and NaHCO3 co-ingestion on buffering capacity and exercise performance with high-intensity exercise in healthy males

Introduction

β-alanine (BAl) and NaHCO₃ (SB) ingestion may provide performance benefits by enhancing concentrations of their respective physiochemical buffer counterparts, muscle carnosine and blood bicarbonate, counteracting acidosis during intense exercise. This study examined the effect of BAl and SB co-supplementation as an ergogenic strategy during high-intensity exercise.

Methods

Eight healthy males ingested either BAl (4.8 g day^?1 for 4 weeks, increased to 6.4 g day^?1 for 2 weeks) or placebo (Pl) (CaCO₃) for 6 weeks, in a crossover design (6-week washout between supplements). After each chronic supplementation period participants performed two trials, each consisting of two intense exercise tests performed over consecutive days. Trials were separated by 1 week and consisted of a repeated sprint ability (RSA) test and cycling capacity test at 110 % Wmax (CCT_110 %). Placebo (Pl) or SB (300 mg kgbw^?1) was ingested prior to exercise in a crossover design to creating four supplement conditions (BAl-Pl, BAl-SB, Pl–Pl, Pl-SB).

Results

Carnosine increased in the gastrocnemius (n = 5) (p = 0.03) and soleus (n = 5) (p = 0.02) following BAl supplementation, and Pl-SB and BAl-SB ingestion elevated blood HCO₃ ^? concentrations (p < 0.01). Although buffering capacity was elevated following both BAl and SB ingestion, performance improvement was only observed with BAl-Pl and BAl-SB increasing time to exhaustion of the CCT_110 % test 14 and 16 %, respectively, compared to Pl–Pl (p < 0.01).

Conclusion

Supplementation of BAl and SB elevated buffering potential by increasing muscle carnosine and blood bicarbonate levels, respectively. BAl ingestion improved performance during the CCT_110 %, with no aggregating effect of SB supplementation (p > 0.05). Performance was not different between treatments during the RSA test.     

Heart rate recovery normality data recorded in response to a maximal exercise test in physically active men

Background

Despite a growing clinical interest in determining the heart rate recovery (HRR) response to exercise, the limits of a normal HRR have not yet been well established.

Purpose

This study was designed to examine HRR following a controlled maximal exercise test in healthy, physically active adult men.

Methods

The subjects recruited (n = 789) performed a maximal stress test on a treadmill. HRR indices were calculated by subtracting the first and third minute heart rates (HRs) during recovery from the maximal HR obtained during stress testing and designated these as HRR-1 and HRR-3, respectively. The relative change in HRR was determined as the decrease in HR produced at the time points 1 and 3 min after exercise as a percentage of the peak HR (%HRR-1/HR_peak and %HRR-3/HR_peak, respectively). Percentile values of HRR-1 and HRR-3 were generated for the study population.

Results

Mean HHR-1 and HHR-3 were 15.24 ± 8.36 and 64.58 ± 12.17 bpm, respectively, and %HRR-1/HR_peak and %HRR-3/HR_peak were 8.60 ± 4.70 and 36.35 ± 6.79 %, respectively. Significant correlation was detected between Peak VO₂ and HRR-3 (r = 0.36; p < 0.001) or %HRR-3/HR_peak (r = 0.23; p < 0.001).

Conclusions

Our study provides normality data for HRR following a maximal Ergometry test obtained in a large population of physically active men.     

Pulmonary O2 uptake kinetics during moderate-intensity exercise transitions initiated from low versus elevated metabolic rates: insights from manipulations in cadence

Introduction

The rate of adjustment (τ) of phase II pulmonary O₂ uptake ( \(\dot{V}{\text{O}}_{{2{\text{p}}}}\) ) is slower when exercise transitions are initiated from an elevated baseline work rate (WR) and metabolic rate (MR). In this study, combinations of cycling cadence (40 vs. 90 rpm) and external WR were used to examine the effect of prior MR on τ \(\dot{V}{\text{O}}_{{2{\text{p}}}}\) .

Methods

Eleven young men completed transitions from 20 W (BSL) to 90 % lactate threshold, with transitions performed as two steps of equal ?WR (LS, lower step; US, upper step), while maintaining a cadence of (1) 40 rpm, (2) 90 rpm, and (3) 40 rpm but with the WRs elevated to match the higher \(\dot{V}{\text{O}}_{{2{\text{p}}}}\) associated with 90 rpm cycling (40_MATCH); transitions lasted 6 min. \(\dot{V}{\text{O}}_{{2{\text{p}}}}\) was measured breath-by-breath using mass spectrometry and turbinometry; vastus lateralis muscle deoxygenation [HHb] was measured using near-infrared spectroscopy. \(\dot{V}{\text{O}}_{{2{\text{p}}}}\) and HHb responses were modeled using nonlinear least squares regression analysis.

Results

\(\dot{V}{\text{O}}_{{2{\text{p}}}}\) at BSL, LS and US was similar for 90 rpm and 40_MATCH, but greater than in 40 rpm. Compared to 90 rpm, τ \(\dot{V}{\text{O}}_{{2{\text{p}}}}\) at 40 rpm was shorter (p < 0.05) in LS (18 ± 5 vs. 28 ± 8 s) but not in US (26 ± 8 vs. 33 ± 9 s), and at 40_MATCH, τ \(\dot{V}{\text{O}}_{{2{\text{p}}}}\) was lower (p < 0.05) (19 ± 6 s) in LS but not in US (34 ± 13 s) despite differing external WR and ?WR.

Conclusions

A similar overall adjustment of [HHb] and \(\dot{V}{\text{O}}_{{2{\text{p}}}}\) in LS and US across conditions suggested dynamic matching between microvascular blood flow and O₂ utilization. Prior MR (rather than external WR per se) plays a role in the dynamic adjustment of pulmonary (and muscle) \(\dot{V}{\text{O}}_{{2{\text{p}}}}\) .     

Influence of thigh activation on the \dot{V}O2 slow component in boys and men

Purpose

During constant work rate exercise above the lactate threshold (LT), the initial rapid phase of pulmonary oxygen uptake ( \(\dot{V}\) O₂) kinetics is supplemented by an additional \(\dot{V}\) O₂ slow component ( \(\dot{V}\) O_2Sc) which reduces the efficiency of muscular work. The \(\dot{V}\) O_2Sc amplitude has been shown to increase with maturation but the mechanisms are poorly understood. We utilized the transverse relaxation time (T ₂) of muscle protons from magnetic resonance imaging (MRI) to test the hypothesis that a lower \(\dot{V}\) O₂ slow component ( \(\dot{V}\) O_2Sc) amplitude in children would be associated with a reduced muscle recruitment compared to adults.

Methods

Eight boys (mean age 11.4 ± 0.4) and eight men (mean age 25.3 ± 3.3 years) completed repeated step transitions of unloaded-to-very heavy-intensity (U → VH) exercise on a cycle ergometer. MRI scans of the thigh region were acquired at rest and after VH exercise up to the \(\dot{V}\) O_2Sc time delay (ScTD) and after 6 min. T ₂ for each of eight muscles was adjusted in relation to cross-sectional area and then summed to provide the area-weighted ΣT ₂ as an index of thigh recruitment.

Results

There were no child/adult differences in the relative \(\dot{V}\) O_2Sc amplitude [Boys 14 ± 7 vs. Men 18 ± 3 %, P = 0.15, effect size (ES) = 0.8] during which the change (?) in area-weighted ΣT ₂ between the ScTD and 6 min was not different between groups (Boys 1.6 ± 1.2 vs. Men 2.3 ± 1.1 ms, P = 0.27, ES = 0.6). A positive and strong correlation was found between the relative \(\dot{V}\) O_2Sc amplitude and the magnitude of the area-weighted ?ΣT ₂ in men (r = 0.92, P = 0.001) but not in boys (r = 0.09, P = 0.84).

Conclusions

This study provides evidence to show that progressive muscle recruitment (as inferred from T ₂ changes) contributes to the development of the \(\dot{V}\) O_2Sc during intense submaximal exercise independent of age.     

Flavones derived from nature attenuate the immediate and late-phase asthmatic responses to aerosolized-ovalbumin exposure in conscious guinea pigs

Objective

Asthma is an inflammatory disease of the lung that is characterized by airway hyperresponsiveness and the increase of inflammatory cell infiltration into the airways. Naturally occurring flavones have potent anti-inflammatory effects, but their effects on asthmatic responses are still relatively unknown.

Methods

We evaluated the inhibitory effects of flavone derivatives having the chromone moiety on the immediate-phase asthmatic response (IAR) and the late-phase asthmatic response (LAR) to aerosolized-ovalbumin (OA) exposure in conscious OA-sensitized guinea pigs.

Results

Luteolin and apigenin (30 mg/kg, p.o.) significantly (P < 0.05) decreased not only the specific airway resistance (sRaw) in IAR and LAR, but also the recruitment of leukocytes and the release of histamine and activities of phospholipase A₂ (PLA₂) and eosinophil peroxide (EPO) in bronchoalveolar lavage fluid (BALF), compared to control. However, their anti-asthmatic activities were less than those of cromolyn sodium and dexamethasone.

Conclusions

These results indicate that flavones containing more hydroxyl radicals have a greater anti-asthmatic effect. The potencies of flavone anti-asthmatic activities are, in order: luteolin ≥ apigenin > baicalein > chrysin > flavone.