Twenty‐four hour variation in heart rate variability indices derived from fractional differintegration

Assuming that RR time‐series behave as a fractionally differintegrated Gaussian process, García‐González et al. (2003) recently proposed new indices for quantifying variability and structure in RR data. One of these was the ‘fractional noise quantifier’ (fnQ), measuring the departure of an RR time‐series from a monofractal structure (i.e. a measure of its multifractality). Sixty‐nine participants (aged = 34·5 ± 12·4 years, body mass index (BMI) = 23·9 ± 2·9 kg m^?2, maximal oxygen uptake rate (O_2peak) = 42·4 ± 10·9 ml min^?1 kg^?1, 39 males) provided continuous beat‐to‐beat ECG recordings for a 24‐h period. Fractional differintegration was used to quantify fnQ, and heart rate variability was calculated in the time domain. All variables were evaluated during consecutive 1‐h periods and also during four 6‐h blocks corresponding to morning, afternoon, evening and night periods. Apart from RR, circadian trends in all variables were independent of gender (P = 0·11–0·59). Apart from fnQ, all variables exhibited circadian variation (0·0005<P<0·012). Although fnQ was statistically uniform during the 24‐h period, it showed a trend towards elevated values during evening and night. The main finding of this study was that fnQ was elevated by around 10% during the evening and night, although this was not statistically significant. This suggests that the structure of RR time‐series in healthy individuals is most strongly ‘multifractal’ during evening and night periods. fnQ appears to be a plausible surrogate measure of multifractality in RR time‐series.     

Ventilation–perfusion inequality and carbon dioxide sensitivity in hypoxaemic chronic obstructive pulmonary disease (COPD) and effects of 6 months of long‐term oxygen treatment (LTOT)

The aim of our study was to find out how blood gas disturbances in stable, eucapnic, severe chronic obstructive pulmonary disease (COPD) patients with an arterial oxygen tension (PaO₂) value of 7·7 (6·1–8·4) kPa are affected by ventilation–perfusion (V_A/Q) relationships and carbon dioxide (CO₂) sensitivity and how these parameters are influenced by 6 months of long‐term oxygen treatment (LTOT). V_A/Q ratios were measured using the multiple inert gas elimination technique (MIGET). Mouth occlusion pressure 0·1 s after onset of inspiration (Pi0·1) and minute ventilation (V_E) were measured to assess respiratory drive response (ΔPi0·1/ΔPCO₂) and hypercapnic ventilatory response (HCVR) to CO₂ rebreathing. At the start of LTOT, a normal median respiratory drive response level of 1·2 (0·2–2·3) cm H₂O/kPa and a low median HCVR as compared with healthy individuals (P<0·001) were found. However, 7·9 (0–29·8)% of the V_E, was directed towards hypoperfused lung areas. The dispersion of ventilation (log SDV; 0·47–1·76), and the dispersion of perfusion (log SDQ; 0·66–1·07) were wider than normal. The PaO₂ level correlated inversely with mean V_A/Q ratio for ventilation (V mean) and shunt. The PaCO₂ level correlated inversely with HCVR and vital capacity. After 6 months of LTOT, no significant changes in daytime blood gas levels, CO₂‐sensitivity or V_A/Q ratios were found. V_E tended to be reduced by 1·0 l min^–1. Conclusions: An elevated V mean and probably shunting are important contributing factors for the reduced PaO₂ and hypercapnic ventilatory response is a major determinant of PaCO₂ in eucapnic stable hypoxaemic COPD. Six months of LTOT does not affect blood gases, CO₂ sensitivity or ventilation–perfusion relationships.     

Influence of long-term oxygen therapy on cardiac acceleration and deceleration capacity in hypoxic patients with chronic obstructive pulmonary disease

Background: There is increasing interest in cardiovascular co‐morbidities of chronic obstructive pulmonary disease (COPD). Heart rate turbulence (HRT) and phase‐rectified signal averaging (PRSA) techniques quantify the heart’s acceleration/deceleration capacities. We postulated that these methods can help assess the integrity of cardiac control in hypoxic COPD. Methods: Eight hypoxic stable COPD patients, nine healthy age‐matched older adults and eight healthy young adults underwent ECG monitoring for 24 h. Patients with COPD were also monitored following 4 weeks of standardized oxygen therapy. HRT measures [turbulence onset (TO), turbulence slope (TS)] and PRSA‐derived acceleration/deceleration (AC, DC) indices were quantified within 6‐h blocks to assess circadian variation. Results: There were between‐group differences for variables TS, DC and AC (P<0·0005, η² = 0·54–0·65), attributable solely to differences between healthy young and COPD subjects. Only HR (P<0·0005) and DC index (P = 0·008) showed circadian variation. A significant interaction ‘trend’ effect for HR (F_9,87 = 2·52, P = 0·015, η² = 0·21) reflected the strong influence of COPD on HR circadian variation (afternoon and night values being different to those in healthy subjects). Conclusions: As expected, heart rate dynamics were substantially diminished in older (healthy and COPD) groups compared with healthy young controls. Patients with COPD showed similar heart rate dynamics compared with age‐matched controls, both before and after hypoxia correction. However, there was a suggestion of diminished DC in COPD compared with age‐matched controls (P = 0·059) that was absent following oxygen therapy. TS, DC and AC indices were altered by similar degrees in older subjects, apparently indicating equivalent tonic dysfunction of sympathetic/parasympathetic systems with ageing.     

Effects of oxygen supplementation on cerebral oxygenation during exercise in chronic obstructive pulmonary disease patients not entitled to long-term oxygen therapy

Background: The rate of change (Δ) in cerebral oxygenation (COx) during exercise is influenced by blood flow and arterial O₂ content (CaO₂). It is currently unclear whether ΔCOx would (i) be impaired during exercise in patients with chronic obstructive pulmonary disease (COPD) who do not fulfil the current criteria for long‐term O₂ therapy but present with exercise‐induced hypoxaemia and (ii) improve with hyperoxia (FIO₂ = 0·4) in this specific sub‐population. Methods: A total of 20 non‐hypercapnic men (FEV₁ = 47·2 ± 11·5% pred) underwent incremental cycle ergometer exercise tests under normoxia and hyperoxia with ΔCOx (fold‐changes from unloaded exercise in O₂Hb) being determined by near‐infrared spectroscopy. Pulse oximetry assessed oxyhaemoglobin saturation (SpO₂), and impedance cardiography estimated changes in cardiac output (ΔQT). Results: Peak work rate and ΔCOx in normoxia were lower in eight O₂‘desaturators’ compared with 12 ‘non‐desaturators’ (P<0·05). Area under ΔCOx during sub‐maximal exercise was closely related to SpO₂ decrements in ‘desaturators’ (r = 0·92, P<0·01). These patients showed the largest improvement in peak exercise capacity with hyperoxia (P<0·05). Despite a trend to lower sub‐maximal ΔQT and mean arterial pressure with active intervention, ΔCOx was significantly improved only in this group (0·57 ± 0·20 versus 2·09 ± 0·42 for ‘non‐desaturators’ and ‘desaturators’, respectively; P<0·05). Conclusions: ΔCOx was impaired in non‐hypoxaemic patients with COPD who desaturated during exercise. Hyperoxic breathing was able to correct for these abnormalities, an effect related to enhanced CaO₂ rather than improved central haemodynamics. This indicates that O₂ supplementation ameliorates exercise COx in patients with COPD who are not currently entitled to ambulatory O₂ therapy.     

Late potentials and QT dispersion after high‐dose chemotherapy in patients with non‐Hodgkin lymphoma

The most common cardiotoxic effects of high‐dose cyclophosphamide (CY) are electrocardiographic changes and transient arrhythmias. Therefore, we prospectively assessed serial electrocardiogram (ECG) and signal‐averaged electrocardiogram (SAECG) recordings in 30 adult patients with non‐Hodgkin lymphoma (NHL) receiving high‐dose CY as part of high‐dose chemotherapy (HDT) regimen. All patients were treated with anthracyclines earlier. Heart‐rate‐corrected QT interval and QT dispersion (QTc and QTc dispersion) were measured from ECG. QRS duration and late potentials (LPs) were analysed from SAECG. Both ECG and SAECG were recorded 1 day (d) prior to HDT (d?7) at baseline, and 1 day (d?2), 7 days (d+7), 12 days (+12) and 3 months (m+3) after HDT. Stem cells were infused on day 0 (d0). Cardiac systolic and diastolic function were assessed on (d?7), (d+12) and (m+3) by radionuclide ventriculography. At baseline, four patients presented with LPs. Cardiac systolic function decreased significantly (53 ± 2; 49 ± 2%, P = 0·009 versus baseline), whilst no patient developed acute heart failure. QRS duration prolonged and RMS₄₀ reduced significantly versus baseline (104 ± 3; 107 ± 3 ms, P = 0·003; 41 ± 4; 38 ± 3 μV, P = 0·03), and six patients (21%) presented with LPs after CY treatment. Both QTc interval and QTc dispersion increased versus baseline (402 ± 5; 423 ± 5 ms, P<0·001; 32 ± 2; 44 ± 3 ms, P = 0·012), and six patients (20%) developed abnormal QT dispersion. In conclusion, high‐dose CY causes subclinical and transient electrical instability reflected by occurrence of LPs as well as increased QTc interval and QT dispersion. Thus, longer follow‐up is required to confirm the meaning of these adverse effects on cardiac function and quality of life.     

Functional near‐infrared spectroscopy to probe sensorimotor region activation during electrical stimulation‐evoked movement

This study used non‐invasive functional near‐infrared spectroscopy (fNIRS) neuroimaging to monitor bilateral sensorimotor region activation during unilateral voluntary (VOL) and neuromuscular electrical stimulation (NMES)‐evoked movements. Methods. In eight healthy male volunteers, fNIRS was used to measure relative changes in oxyhaemoglobin (O₂Hb) and deoxyhaemoglobin (HHb) concentrations from a cortical sensorimotor region of interest in the left (LH) and right (RH) hemispheres during NMES‐evoked and VOL wrist extension movements of the right arm. Results. NMES‐evoked movements induced significantly greater activation (increase in O₂Hb and concomitant decrease in HHb) in the contralateral LH than in the ipsilateral RH (O₂Hb: 0·44 ± 0·16 μM and 0·25 ± 0·22 μM, P = 0·017; HHb: ?0·19 ± 0·10 μM and ?0·12 ± 0·09 μM, P = 0·036, respectively) as did VOL movements (0·51 ± 0·24 μΜ and 0·34 ± 0·21 μM, P = 0·031; HHb: ?0·18 ± 0·07 μΜ and ?0·12 ± 0·04 μΜ, P = 0·05, respectively). There was no significant difference between conditions for O₂Hb (P = 0·144) and HHb (P = 0·958). Conclusion. fNIRS neuroimaging enables quantification of bilateral sensorimotor regional activation profiles during voluntary and NMES‐evoked wrist extension movements.     

Effect of set configuration on hemodynamics and cardiac autonomic modulation after high‐intensity squat exercise

The aim of this study was to compare the effect of two different high‐intensity resistance exercise (RE) set configurations on the following: systolic blood pressure (SBP), rate pressure product (RPP), heart rate (HR) variability (HRV), and HR complexity (HRC). Ten well‐trained males performed three parallel squat sets until failure (traditional training; TT) with the four repetitions maximum load (4RM), and a rest of 3 min between sets. Thereafter, participants performed a cluster training session (CT) of equated load but with resting time distributed between each repetition. Dependent variables were recorded before, during, and after RE. Mean SBP (25·7 versus 10·9% percentage increase; P = 0·016) and RPP (112·5 versus 69·9%; P = 0·01) were significantly higher in TT. The decrease in HRV after exercise and the drop of HRC during exercise were similar in CT and TT. Change of standard deviation of normal RR intervals after TT correlated with change in SBP (r = 0·803; P = 0·009) while the change of Sample Entropy during exercise correlated with the increment of RPP during CT (ρ = ?0·667; P = 0·05). This study suggests that set configuration influences acute cardiovascular responses during RE. When intensity, volume and work‐to‐rest ratio are equated, CT is less demanding in terms of SBP and RPP. A greater hemodynamic response during exercise would be associated with a faster parasympathetic recovery.     

Interventions to reduce vasovagal reactions in blood donors: a systematic review and meta‐analysis

Vasovagal reactions (VVRs) in blood donors have significant implications for the welfare of donors, donor retention and the management of donor sessions. We present a systematic review of interventions designed to prevent or reduce VVRs in blood donors. Electronic databases were searched for eligible randomised trials to March 2015. Data on study design and outcomes were extracted and pooled using random effects meta‐analyses. Sixteen trials met the inclusion criteria: five trials (12 042 participants) of pre‐donation water, eight trials (3500 participants) of applied muscle tension (AMT) and one trial each of AMT combined with water, caffeine, audio‐visual distraction and/or social support. In donors receiving pre‐donation water, the relative risk (RR) compared with controls for VVRs was 0·79 [95% confidence interval (CI) 0·70–0·89, P < 0·0001] and the mean difference (MD) in severity of VVRs measured with the Blood Donation Reactions Inventory (BDRI) score was ?0·32 (95% CI ?0·51 to ?0·12, P < 0·0001). Excluding trials with a high risk of selection bias, the RR for VVRs was 0·70 (95% CI 0·45–1·11, P = 0·13). In donors who received AMT, there was no difference in the risk of chair recline in response to donor distress from controls (RR 0·76, 95% CI 0·53–1·10, P = 0·15), although the MD in BDRI score was ?0·07 (95% CI ?0·11 to ?0·03, P = 0·0005). There was insufficient data to perform meta‐analysis for other interventions. Current evidence on interventions to prevent or reduce VVRs in blood donors is indeed limited and does not provide strong support for the administration of pre‐donation water or AMT during donation. Further large trials are required to reliably evaluate the effect of these and other interventions in the prevention of VVRs.     

Plasma protein thiols: an early marker of oxidative stress in asthma and chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) and asthma are both characterized by heterogeneous chronic airway inflammation and obstruction as well as oxidative stress (OS). However, it is unknown whether OS occurs in early disease and how to best assess its presence. Plasma OS markers (TBARS, PSH, taurine, GSH, ergothioneine and paraoxonase 1 activity) and lung function tests were measured in patients with mild stable asthma (n = 24) and mild stable COPD (n = 29) and in age‐ and sex‐matched controls. Forced expiratory volume in 1 s (FEV₁) was associated with age both in patients and control groups. By contrast, FEV₁ was positively correlated with PSH only in COPD (ρ = 0·49, P = 0·007). In multiple logistic regression analysis, lower PSH was the only OS marker independently associated with increased odds of both asthma (OR = 0·32, 95% CI 0·13–0·78, P = 0·01) and COPD (OR = 0·50, 95% CI 0·26–0·95, P = 0·03). These findings suggest that proteins ‐SH are a sensitive OS marker in early COPD and asthma.     

A comparison of dynamic contrast‐enhanced CT and MR imaging‐derived measurements in patients with cervical cancer

This work is to compare the kinetic parameters derived from the DCE‐CT and ‐MR data of a group of 37 patients with cervical cancer. The modified Tofts model and the reference tissue method were applied to estimate kinetic parameters. In the MR kinetic analyses using the modified Tofts model for each patient data set, both the arterial input function (AIF) measured from DCE‐MR images and a population‐averaged AIF from the literature were applied to the analyses, while the measured AIF was used for the CT kinetic analysis. The kinetic parameters obtained from both modalities were compared. Significant moderate correlations were found in modified Tofts parameters [volume transfer constant(K^trans) and rate constant (k_ep)] between CT and MR analysis for MR with the measured AIFs (R = 0·45, P<0·01 and R = 0·40, P<0·01 in high‐K^trans region; R = 0·38, P<0·01 and R = 0·80, P<0·01 in low‐K^trans region) as well as with the population‐averaged AIF (R = 0·59, P<0·01 and R = 0·62, P<0·01 in high‐K^trans region; R = 0·50, P<0·01 and R = 0·63, P<0·01 in low‐K^trans region), respectively. In addition, from the Bland–Altman plot analysis, it was found that the systematic biases (the mean difference) between the modalities were drastically reduced in magnitude by adopting the population‐averaged AIF for the MR analysis instead of the measured ones (from 51·5% to 18·9% for K^trans and from 21·7% to 4·1% for k_ep in high‐K^trans region; from 73·0% to 29·4% for K^trans and from 63·4% to 24·5% for k_ep in low‐K^trans region). The preliminary results showed the feasibility in the interchangeable use of the two imaging modalities in assessing cervical cancers.     

Technetium‐99m‐anti‐tumour necrosis factor alpha scintigraphy as promising predictor of response to corticotherapy in chronic active Graves' ophthalmopathy

It has been suggested that technetium‐99m (99mTc)‐anti‐tumour necrosis factor alpha (TNF‐α) scintigraphy (SCI) may be a useful diagnostic tool in Graves' ophthalmopathy (GO). This study evaluated whether orbit total radioactivity uptake on SCI could be used to predict corticosteroid therapy (CorT) responses in active‐GO patients. A longitudinal study of patients with active GO defined by Clinical Active Score (CAS) >3/7 was done. Clinical, laboratory and SCI evaluations were performed at baseline and 3 months after concluding intravenous CorT. SCI (planar and tomographic) was assessed after intravenous injection of 10 mCi of 99mTc‐anti‐TNF‐α. Orbits and cerebral hemispheres were defined as regions of interest (ROIs) to enable orbit/hemisphere ROI‐ratios of total radioactive uptake. ROI‐ratios were considered positive at >2·5. Average total radiation uptake (TRU) was also determined for each orbit (AVG_ROI). Clinical, laboratory and SCI data were compared between responders (CAS became inactive) and non‐responders to CorT (18 patients). At baseline, AVG_ROI were higher in active OG orbits (67·3 cps) than in inactive ones (33·6 cps; P<0·05). AVG_ROI (absolute values) reduced (?29·9 cps) in CorT responders and tended (P = 0·067) to differ from variations occurred in non‐responders (+6·9 cps in patients with maintained CAS positivity post‐treatment). Higher baseline ROI‐ratios (4·9 versus 3·3; P = 0·056) and its pronounced reductions following CorT (?37% versus +56% in non‐responders; P = 0·036) tended to be associated with good CorT responses in the subgroup of GO history ≥1 year. SCI showed a good association with active eye disease and may be an additional tool to identify CorT responders.     

Maximal explosive muscle power in obese and non‐obese prepubertal children

Objective: The objectives of the present study was to compare the maximal explosive muscle power developed by the lower limbs in obese and non‐obese prepubertal children. Design: Twenty‐five obese [mean body mass index (BMI) z‐score: 2·4] and 30 non‐obese (mean BMI z‐score: 0) children aged 8–12 years, participated in this study. Body composition was measured by bioelectrical impedance analysis and the maximal explosive power of the lower limbs was assessed by the Exercise‐Ergometer (a sledge dynamometer). Results: Absolute peak force (F_peak) was higher in obese than in non‐obese children by 18·2% (P<0·001). Peak speed (v_peak) was not significantly different between groups (P = 0·504). Consequently, absolute peak power (W′_peak) was higher in obese than in non‐obese children (+19·3%, P = 0·021). Considering gender differences, absolute F_peak and v_peak were higher in boys than in girls by +12·3 and +17·4% (P<0·05), respectively, thus yielding higher absolute W′_peak values in boys as compared to girls (+26·1%, P<0·001). Finally, W′_peak normalized for fat‐free mass (FFM) was not different between obese and non‐obese children but higher in boys than in girls (+24·5%, P<0·001). Conclusions: Power generation capability per unit of FFM was similar between obese and non‐obese children but was significantly higher in boys than girls. On the clinical practice it seems important to devote supplementary care to sustain and improve the motor function of obese and non‐obese girls.     

Predictors of the intima‐media thickness of carotid artery in asymptomatic newly detected severe hypercholesterolemic patients

Background: Data about predictors of intima‐media thickness (IMT) of common carotid artery (CCA) in asymptomatic subjects with newly detected severe hypercholesterolemia is scarce. Aim: This research is aimed at studying the predictors of the IMT of CCA among basic atherogenic risk biomarkers – lipid [total cholesterol (TC), triglycerides, high‐density lipoprotein cholesterol, low‐density lipoprotein (LDL) cholesterol, Apolipoprotein‐B, Apolipoprotein‐Ai, Apolipoprotein‐B/A₁ index] and non‐lipid, [asymmetric dimethylarginine (ADMA), total homocysteine, cell adhesion molecules] in asymptomatic subjects with newly detected severe hypercholesterolemia. Methods: Two hundred and fifty asymptomatic patients with severe, newly hypercholesterolemia and 200 controls were evaluated. Hypercholesterolemia was defined as TC > 7·5 mm and LDL cholesterol > 4·9 mm . The ADMA and cell adhesion molecules were determined by ELISA and total homocysteine by high‐performance liquid chromatography. Results: There was significant difference between the two groups in respect to all lipid biomarkers (P<0·001). Hypercholesterolemic patients had significantly higher level of ADMA, sVCAM‐1, sICAM‐1, IMT (P<0·001), whereas no significant difference was found between two groups with respect to total homocysteine, P‐selectin and E‐selectin (P>0·05). A strong positive correlation between IMT mean and age (r_xy = 0·714; P<0·001), Apolipoprotein‐B (r_xy = 0·706; r_xy < 0·001), Apolipoprotein‐B/A₁ (r_xy = 0·324; P<0·001), ADMA (r_xy = 0·603; P<0·001) was found. The subsequent linear and multiple regression analysis selected age and Apolipoprotein‐B as most significant factors in relation to IMT mean. Apolipoprotein‐B is a better factor for assessment of risk, as LDL cholesterol underestimates the risk in asymptomatic subjects with newly detected severe hypercholesterolemia, until more rapid and feasible methods for measurement of small and dense LDL are available.     

Validation of a single‐stage fixed‐rate step test for the prediction of maximal oxygen uptake in healthy adults

Healthcare professionals with limited access to ergospirometry remain in need of valid and simple submaximal exercise tests to predict maximal oxygen uptake (VO_2max). Despite previous validation studies concerning fixed‐rate step tests, accurate equations for the estimation of VO_2max remain to be formulated from a large sample of healthy adults between age 18–75 years (n > 100). The aim of this study was to develop a valid equation to estimate VO_2max from a fixed‐rate step test in a larger sample of healthy adults. A maximal ergospirometry test, with assessment of cardiopulmonary parameters and VO_2max, and a 5‐min fixed‐rate single‐stage step test were executed in 112 healthy adults (age 18–75 years). During the step test and subsequent recovery, heart rate was monitored continuously. By linear regression analysis, an equation to predict VO_2max from the step test was formulated. This equation was assessed for level of agreement by displaying Bland–Altman plots and calculation of intraclass correlations with measured VO_2max. Validity further was assessed by employing a Jackknife procedure. The linear regression analysis generated the following equation to predict VO_2max (l min^?1) from the step test: 0·054(BMI)+0·612(gender)+3·359(body height in m)+0·019(fitness index)?0·012(HRmax)?0·011(age)?3·475. This equation explained 78% of the variance in measured VO_2max (F = 66·15, P<0·001). The level of agreement and intraclass correlation was high (ICC = 0·94, P<0·001) between measured and predicted VO_2max. From this study, a valid fixed‐rate single‐stage step test equation has been developed to estimate VO_2max in healthy adults. This tool could be employed by healthcare professionals with limited access to ergospirometry.     

Temporal age‐related changes in spectral,fractal and complexity characteristics of heart rate variability

Cross‐sectional studies have suggested that heart rate (HR) variability, analysed using traditional time and frequency domain methods, is related to ageing, but no longitudinal studies have estimated the age dependence of HR fluctuation. This study evaluated temporal age‐related changes in 12‐h measures of HR variability among 109 patients with coronary artery disease (CAD), who underwent repeat Holter recordings at 32‐month intervals. Time and frequency domain measures, along with fractal and complexity measures of HR variability, were determined at the baseline and after 32 months. Changes in HR dynamics were compared with various laboratory variables, exercise data and angiographic progression of CAD. Traditional time and frequency domain measures of HR variability did not change significantly during the follow‐up, but the power‐law scaling slope decreased from ?1·29 ± 0·20 to ?1·36 ± 0·23 (P<0·01) and the short‐term fractal exponent (α₁) of HR dynamics from 1·29 ± 0·14–1·22 ± 0·18 (P<0·001). The approximate entropy value also decreased from 1·00 ± 0·19 to 0·95 ± 0·18 (P<0·05). The changes in HR behaviour were not related to demographic data, laboratory values or angiographic progression of CAD. Only a weak correlation was observed between the change in the power‐law slope and the baseline glucose value (P<0·05). This longitudinal study shows that the fractal characteristics of HR dynamics and the complexity properties of R‐R intervals undergo rapid changes along with ageing, and that fractal and complexity analysis techniques are more sensitive than traditional analysis methods in documenting temporal age‐related changes in HR behaviour.     

Effects of long‐term clarithromycin treatment on lavage‐fluid markers of inflammation in chronic rhinosinusitis

Macrolides can be clinically effective in chronic rhinosinusitis (CRS). However, little is known about how these drugs affect pathophysiological features of CRS in vivo. In the present study, patients with CRS were subjected to long‐term treatment with clarithromycin. Nasal lavages with and without histamine (40 and 400 μg ml^?1) were carried out prior to and late into the treatment period. Histamine was included as a tool to produce plasma exudation, a process known to move free cellular products from the mucosal tissue into the airway lumen thereby enriching nasal surface liquids with such products. Interleukin‐8 (IL‐8), myeloperoxidase (MPO), eosinophil cationic protein (ECP), α₂‐macroglobulin and fucose were monitored as indices of pro‐inflammatory cytokine production, neutrophil and eosinophil granulocyte activities, plasma exudation and mucinous secretion, respectively. Clarithromycin reduced the lavage fluid levels of IL‐8 at the low‐dose histamine observation (P<0·001). There was a trend towards reduced MPO by the treatment, whereas ECP was significantly reduced at the low‐dose histamine observation (P<0·05). α₂‐Macroglobulin was reduced by clarithromycin (saline lavages) (P = 0·05), whereas fucose was unaffected. The exudative responsiveness to high‐dose histamine was significantly reduced by the treatment (P<0·05). Furthermore, significantly lower levels of fucose were observed at the low‐dose histamine observation (P<0·01). We conclude that long‐term clarithromycin treatment likely exerts an anti‐inflammatory effect in CRS.     

The effectiveness of silver‐releasing dressings in the management of non‐healing chronic wounds: a meta‐analysis

Aim. The purpose of this study was to examine the efficacy of silver‐releasing dressings in the management of non‐healing chronic wounds. Background. Non‐healing chronic wounds often have a negative physical impact on patients and place a financial burden on healthcare systems. Silver dressings are wound products designed to control infection and provide a wound environment conducive to healing. However, validation of the clinical efficacy of these dressings is lacking. Design. Systematic review and meta‐analysis. Methods. A systematic search of the major electronic databases PubMed, CINAHL, Cochrane, MEDLINE, British Nursing Index, EBSCO, OCLC and Proquest between 1950–June 2007 was conducted. Hand searches of selected periodicals, textbooks and checking reference lists and contacting experts was also performed. Results. Eight studies were selected from a potentially relevant 1957 references screened. Analysis incorporated data from 1399 participants in the eight randomised control trials. We found that silver dressings significantly improved wound healing (CI₉₅: 0·16–0·39, p < 0·001), reduced odour (CI₉₅: 0·24–0·52, p < 0·001) and pain‐related symptoms (CI₉₅: 0·18–0·47, p < 0·001), decreased wound exudates (CI₉₅: 0·17–0·44, p < 0·001) and had a prolonged dressing wear time (CI₉₅: 0·19–0·48, p = 0·028) when compared with alternative wound management approaches. An analysis of sensitivity in these studies by subgroup analysis generally supported these associations. Furthermore, studies indicated an improvement in quality of life (CI₉₅: 0·04–0·33, p = 0·013) using silver dressings in wound management with no associated severe adverse events. Conclusion. This meta‐analysis confirms the effectiveness of silver dressings in wound healing and improving patients’ quality of life. However, it also highlights the need for additional well‐designed randomised controlled trials to evaluate the effectiveness of silver‐related dressings further. Relevance to clinical practice. The results of this study provide objective data on the effectiveness of silver‐related dressing when applied to non‐healing chronic wounds.     

Left ventricular diastolic function is enhanced after peak exercise in endurance‐trained adolescents as well as in their non‐trained controls

The aims of the study were to explore the temporal change of cardiac function after peak exercise in adolescents, and to investigate how these functional changes relate to maximal oxygen uptake (VO_2max). The cohort consisted of 27 endurance‐trained adolescents aged 13–19 years, and 27 controls individually matched by age and gender. Standard echocardiography and colour tissue Doppler were performed at rest, and immediately after as well as 15 min after a maximal cardio pulmonary exercise test (CPET) on a treadmill. The changes in systolic and diastolic parameters after exercise compared to baseline were similar in both groups. The septal E/e′‐ratio increased immediately after exercise in both the active and the control groups (from 9·2 to 11·0; P<0·001, and from 8·7 to 10·2; P = 0·008, respectively). In a comparison between the two groups after CPET, the septal E/e′‐ratio was higher in the active group both immediately after exercise and 15 min later compared to the control group (P = 0·007 and P = 0·006, respectively). We demonstrated a positive correlation between VO_2max and cardiac function including LVEF and E/e′ immediately after CPET, but the strongest correlation was found between VO_2max and LVEDV (r = 0·67, P<0·001) as well as septal E/e′ (r = 0·34, P = 0·013). Enhanced diastolic function was found in both groups, but this was more pronounced in active adolescents. The cardiac functional response to exercise, in terms of LVEF and E/e′, correlates with the increase in VO₂ uptake. These findings in trained as well as un‐trained teenagers have practical implications when assessing cardiac function.     

Effects of short‐term detraining following blood flow restricted low‐intensity training on muscle size and strength

We investigated the effects of 3 weeks of detraining on muscle cross‐sectional area (CSA) and one‐repetition maximum strength (1‐RM) in young men who had previously participated in 6 weeks (3 days week^?1) of bench press training [blood flow restricted low‐intensity (LI‐BFR; n = 10, 20% 1‐RM) or high‐intensity (HI; n = 7, 75% 1‐RM)]. Bench press 1‐RM and muscle CSA of triceps brachii (TB) and pectoralis major (PM) were evaluated before (pre) and after training period (post) as well as after detraining period (detraining). Bench press 1‐RM was higher at both post and detraining than at pre for LI‐BFR (P<0·01) and the HI (P<0·01). TB and PM muscle CSA were higher at both post and detraining than at pre for the HI group (P<0·01), while the LI‐BFR group only increased (P<0·01) at post. Relative dynamic strength (1‐RM divided by TB muscle CSA) was higher at both post and detraining than at pre for the HI group (P<0·01), while the LI‐BFR group only increased (P<0·01) at detraining. In conclusion, increased muscle strength following 6 weeks of training with LI‐BFR as well as HI was well preserved at 3 weeks of detraining. HI‐induced muscle strength appears to be dependent upon both neural adaptations and muscle hypertrophy with training and detraining. On the other hand, LI‐BFR‐induced muscle strength appears to be related primarily to muscle hypertrophy with training and to neural adaptations with detraining.