Effects of 24-week prebiotic intervention on self-reported upper respiratory symptoms, gastrointestinal symptoms, and markers of immunity in elite rugby union players.

OBJECTIVES: Elite rugby union players face numerous physiological and psychological stressors which can increase upper respiratory and gastrointestinal illness risk, and in turn can compromise training and competitive performance. This study aimed to investigate the effect of daily prebiotic supplementation on upper respiratory symptoms, gastrointestinal symptoms, and markers of immune function in elite rugby union players. METHODS: Thirty-three elite rugby union players were randomly assigned to consume a prebiotic (2.8 g/day galactooligosaccharide) or placebo (2.8 g/day maltodextrin), daily for 168 days under double-blind conditions. Participants completed daily and weekly questionnaires for self-reported upper respiratory and gastrointestinal symptoms respectively. Blood and saliva samples were collected at 0, 84, and 168 days for assessment of plasma TNF-α and CRP, and saliva IgA respectively. RESULTS: The prebiotic group experienced a 2-day reduction in upper respiratory symptom duration (P = 0.045). Gastrointestinal symptom severity and incidence were lower in the prebiotic group compared to the placebo group (P < 0.001, P = 0.041) respectively. Salivary immunoglobulin A secretion rate was 42% greater in the prebiotic group compared to the placebo group at day 168 (P = 0.004), no differences in CRP and TNF-α were found (P > 0.05). CONCLUSION: A 168-day dietary prebiotic intervention reduced the duration of upper respiratory symptoms and reduced the incidence and severity of gastrointestinal symptoms in elite rugby union players. These findings suggest that seasonal prebiotic interventions may be beneficial for reducing illness in elite rugby union players, improving their availability to train and compete.Key pointsElite athletes are susceptible to upper respiratory symptoms and gastrointestinal symptoms which may impact upon training availability and competition performance.For the first time, this study shows that a dietary prebiotic intervention can reduce the duration of upper respiratory symptoms by 2 days in elite rugby union players.Dietary prebiotic supplementation can improve the incidence and severity of gastrointestinal symptoms experienced by elite rugby union players.Prebiotic supplementation was able to increase salivary IgA secretion after 168 days.These findings can inform practice suggesting that seasonal prebiotic use has the potential to modulate immune function and reduce illness in elite rugby union, which may improve a player's availability to train and compete.The mechanisms by which prebiotics reduce URS and GIS require further research exploration.

The effect of trait self-control on dyspnoea and tolerance to a CO2 rebreathing challenge in healthy males and females.

BACKGROUND: High trait self-control is associated with greater tolerance of unpleasant sensations including effort and pain. Dyspnoea and pain have several commonalities and this study aimed to investigate for the first time whether trait self-control influences responses to a hypercapnic rebreathing challenge designed to induce dyspnoea. As sex also influences tolerance to dyspnoea, we also sought to investigate whether this moderated the role of trait self-control. METHODS: Participants (n = 65, 32 females) scoring high or low for trait self-control, performed a standardised rebreathing challenge, in which inspired carbon dioxide (CO2) gradually increased over a period of 6 min or until an intolerable level of dyspnoea. Air hunger (AH) intensity - a distinctive quality of dyspnoea, was measured every 30 s. The multidimensional dyspnoea profile (MDP) was completed after the rebreathing challenge for a more complete overview of breathing discomfort. RESULTS: Males high in trait self-control (SCHIGH) (302 ± 42 s), tolerated the rebreathing challenge for longer than males low in self-control (SCLOW) (252 ± 66 s, P = 0.021), experienced slower increases in AH intensity during the rebreathing challenge (0.03 ± 0.01 cm.s - 1 vs. 0.04 ± 0.01 cm.s - 1,P = 0.045) and reported lower perceived mental effort on the MDP (4.94 ± 2.46 vs. 7.06 ± 1.60, P = 0.007). There was no difference between SCHIGH and SCLOW females for challenge duration. However, SCHIGH females (9.29 ± 0.66 cm) reported greater air hunger at the end of the challenge than SCLOW females (7.75 ± 1.75 cm, P = 0.003). It is possible that SCLOW females were unwilling to tolerate the same perceptual intensity of AH as the SCHIGH females. CONCLUSIONS: These results indicate that individuals high in trait self-control are more tolerant of dyspnoea during a CO2 rebreathing challenge than low self-control individuals. Tolerance of the stimulus was moderated by the sex of the participant, presenting an interesting opportunity for future research.

Locomotor muscle fatigue is not critically regulated after prior upper body exercise.

This study examined the effects of prior upper body exercise on subsequent high-intensity cycling exercise tolerance and associated changes in neuromuscular function and perceptual responses. Eight men performed three fixed work-rate (85% peak power) cycling tests: 1) to the limit of tolerance (CYC); 2) to the limit of tolerance after prior high-intensity arm-cranking exercise (ARM-CYC); and 3) without prior exercise and for an equal duration as ARM-CYC (ISOTIME). Peripheral fatigue was assessed via changes in potentiated quadriceps twitch force during supramaximal electrical femoral nerve stimulation. Voluntary activation was assessed using twitch interpolation during maximal voluntary contractions. Cycling time during ARM-CYC and ISOTIME (4.33 ± 1.10 min) was 38% shorter than during CYC (7.46 ± 2.79 min) (P < 0.001). Twitch force decreased more after CYC (-38 ± 13%) than ARM-CYC (-26 ± 10%) (P = 0.004) and ISOTIME (-24 ± 10%) (P = 0.003). Voluntary activation was 94 ± 5% at rest and decreased after CYC (89 ± 9%, P = 0.012) and ARM-CYC (91 ± 8%, P = 0.047). Rating of perceived exertion for limb discomfort increased more quickly during cycling in ARM-CYC [1.83 ± 0.46 arbitrary units (AU)/min] than CYC (1.10 ± 0.38 AU/min, P = 0.003) and ISOTIME (1.05 ± 0.43 AU/min, P = 0.002), and this was correlated with the reduced cycling time in ARM-CYC (r = -0.72, P = 0.045). In conclusion, cycling exercise tolerance after prior upper body exercise is potentially mediated by central fatigue and intolerable levels of sensory perception rather than a critical peripheral fatigue limit.

Reproducibility of the bronchoconstrictive response to eucapnic voluntary hyperpnoea.

BACKGROUND: Eucapnic voluntary hyperpnoea (EVH) is considered an effective bronchoprovocation challenge for identifying exercise-induced bronchoconstriction (EIB). However, the reproducibility of the hyperpnoea-induced bronchoconstriction (HIB) response elicited by EVH remains unknown and was therefore the focus of this study. METHODS: Two cohorts of 16 physically active males (each cohort comprised 8 controls and 8 with physician diagnosis of asthma) participated in two studies of the short- and long-term reproducibility of the bronchoconstrictive response to an EVH test with dry air. EVH was performed on days 0, 7, 14, and 21 (short-term study), and 0, 35, and 70 (long-term study). HIB was diagnosed by a ≥10% fall in forced expiratory volume in 1 s (FEV1) after EVH. RESULTS: On day 0 of the short-term study, FEV1 fell by 2 ± 1% (P < 0.05) and 27 ± 18% (P < 0.01) from pre-to post-EVH in control and HIB-positive groups respectively. The post-EVH fall in FEV1 did not differ across the short-term study test days. In the HIB-positive group, the day-to-day coefficient of variation, reproducibility, and smallest meaningful change for the fall in FEV1 were 12%, 328 mL, and 164 mL, respectively. On day 0 of the long-term study, FEV1 fell by 2 ± 2% and 25 ± 18% (P < 0.01) after EVH in control and HIB-positive groups respectively. The post-EVH fall in FEV1 did not differ across the long-term study test days. In the HIB-positive group, the day-to-day coefficient of variation, reproducibility, and smallest meaningful change for the fall in FEV1 were 10%, 196 mL, and 98 mL respectively. CONCLUSION: The EVH test elicits a reproducible bronchoconstrictive response in physically active males with physician diagnosed asthma. These data thus support the clinical utility of the EVH test for EIB screening and monitoring.

Inspiratory muscle warm-up does not improve cycling time-trial performance.

PURPOSE: This study examined the effects of an active cycling warm-up, with and without the addition of an inspiratory muscle warm-up (IMW), on 10-km cycling time-trial performance. METHODS: Ten cyclists (VO2 = 65 ± 9 mL kg(-1) min(-1)) performed a habituation 10-km cycling time-trial and three further time-trials preceded by either no warm-up (CONT), a cycling-specific warm-up (CYC) comprising three consecutive 5-min bouts at powers corresponding to 70, 80, and 90% of the gas exchange threshold, or a cycling-specific warm-up preceded by an IMW (CYC + IMW) comprising two sets of 30 inspiratory efforts against a pressure-threshold load of 40% maximal inspiratory pressure (MIP). The cycling warm-up was followed by 2-min rest before the start of the time-trial. RESULTS: Time-trial performance times during CYC (14.75 ± 0.79 min) and CYC + IMW (14.70 ± 0.75 min) were not different, although both were faster than CONT (14.99 ± 0.90 min) (P < 0.05). Throughout the time-trial, physiological (minute ventilation, breathing pattern, pulmonary gas exchange, heart rate, blood lactate concentration and pH) and perceptual (limb discomfort and dyspnoea) responses were not different between CYC and CYC + IMW. Baseline MIP during CONT and CYC was 151 ± 31 and 156 ± 39 cmH2O, respectively, and was unchanged following the time-trial. MIP increased by 8% after IMW (152 ± 27 vs. 164 ± 27 cmH2O, P < 0.05) and returned to baseline after the time-trial. CONCLUSIONS: Improvements in 10-km cycling time-trial performance following an active cycling warm-up were not magnified by the addition of an IMW. Therefore, an appropriately designed active whole-body warm-up does adequately prepare the inspiratory muscles for cycling time-trials lasting approximately 15 min.

Effects of protocol design on lactate minimum power.

The aim of this investigation was to use a validated lactate minimum test protocol and evaluate whether blood lactate responses and the lactate minimum power are influenced by the starting power (study 1) and 1 min inter-stage rest intervals (study 2) during the incremental phase. Study 1: 8 subjects performed a lactate minimum test comprising a lactate elevation phase, recovery phase, and incremental phase comprising 5 continuous 4 min stages with starting power being 40% or 45% of the maximum power achieved during the lactate elevation phase, and with power increments of 5% maximum power. Study 2: 8 subjects performed 2 identical lactate minimum tests except that during one of the tests the incremental phase included 1 min inter-stage rest intervals. The lactate minimum power was lower when the incremental phase commenced at 40% (175±29 W) compared to 45% (184±30 W) maximum power (p<0.01), and was increased when 1 min inter-stage rest intervals were included during the incremental phase (192±25 vs. 200±26 W, p<0.01). In conclusion, changes in lactate minimum power were small and thus unlikely to compromise test validity and therefore training status evaluation and exercise prescription.

Investigations of the lactate minimum test.

We evaluated: the agreement between lactate minimum and maximal lactate steady state (MLSS) cycling powers (study 1); whether rates of change of blood lactate concentration during the lactate minimum test reflect that of constant power exercise (study 2); whether the lactate minimum power is influenced by the muscle groups used to elevate blood lactate concentration (study 3). Study 1: 32 subjects performed a lactate minimum test comprising a lactate elevation phase, recovery phase, and incremental phase (five 4 min stages); MLSS was subsequently determined. Study 2: 8 subjects performed a lactate minimum test and five 22 min constant power tests at the incremental phase exercise intensities. Study 3: 10 subjects performed two identical lactate minimum tests, except during the second test the lactate elevation phase comprised arm-cranking. Lactate minimum and MLSS powers demonstrated good agreement (mean bias+/-95% limits of agreement: 2+/-22 W). Rates of change of blood lactate concentration during each incremental phase stage and corresponding constant power test did not correlate. Lactate minimum power was lowered when arm-cranking was used during the lactate elevation phase (157+/-29 vs. 168+/-21 W; p<0.05). The lactate elevation phase modifies blood lactate concentration responses during the incremental phase, thus good agreement between lactate minimum and MLSS powers seems fortuitous.

A 4-year follow-up study of atopic dermatitis therapy with 0.1% tacrolimus ointment in children and adult patients.

BACKGROUND: For the treatment of a chronic disease like atopic dermatitis, sustained tolerability and efficacy of the applied medication are essential. OBJECTIVES: The present open-label, noncomparative study was conducted to obtain information on the long-term safety and efficacy of 0.1% tacrolimus ointment. METHODS: Patients aged 2 years or older with an affected body surface area of more than 5%, who previously participated in a clinical trial on tacrolimus ointment, were eligible for this study. The treatment area was defined by the investigator at study entry. Both children and adults applied continuously or intermittently 0.1% tacrolimus ointment twice daily during episodes of active disease plus an additional week after remission over a follow-up period of up to 4 years. RESULTS: The intent-to-treat population comprised 782 patients, with a median age of 22 years (range 2-72). Patients remained in the study for up to 4 years. Approximately half of the patients discontinued the study prematurely; the median follow-up was 1422 days. Median tacrolimus ointment use was 31.2 g during the first week; ointment use decreased during the first year and then remained stable for the remainder of the study. The median cumulative tacrolimus use was 271.5 g at month 6, 462.5 g at month 12, 739.9 g at month 24, 1029.3 g at month 36 and 1320.8 g at month 48. Altogether 51.8% of patients discontinued the study prematurely; the main reasons were withdrawal of consent (13.3%), loss to follow-up (11.3%) and lack of efficacy (9.4%). Adverse events led to study discontinuation in 3.7% of the patients. The most frequent application site events were skin burning and pruritus. These events were most often reported in adult patients during the initial treatment period; prevalence decreased after the first week and remained at a low level throughout the study. Nonapplication site events occurred with stable incidences throughout the study period. In general, calculated daily hazard rates did not indicate an increased risk of adverse events with prolonged treatment. The total affected body surface area decreased substantially upon onset of treatment and efficacy of treatment was maintained until the end of the study with smaller but continuous improvements throughout the follow-up period. Overall, 75% of the patients and 76% of the investigators rated their satisfaction with the treatment as excellent, very good or good at the end of the study or at the time of premature discontinuation. CONCLUSIONS: The safety profile of intermittent or continuous long-term application of 0.1% tacrolimus ointment for up to 4 years was consistent with that which has been established from shorter studies and gave no reason for concern. In addition, 0.1% tacrolimus ointment demonstrated sustained efficacy as reflected by the expression of high satisfaction with treatment by both patients and investigators.

Attitudes regarding specialist referrals in periodontics.

OBJECTIVE: To examine the attitudes of dental practitioners towards specialist periodontal referral in the North East of England. SUBJECTS AND METHODS: Semi-structured interviews were conducted with a purposive sample of 10 practitioners. Interviews continued until data saturation occurred. The data were organised using a framework and analysed by two researchers working independently. RESULTS: Perceptions of periodontal disease and treatment appear to be heavily influenced by the NHS remuneration system. Treatment in general practice was limited to simple scaling and there was an apparent reluctance to treat advanced periodontitis. Such cases were commonly referred to specialists, confirming the demand for a referral service in periodontics. The perceived potential for medico-legal consequences was a strong driver of referrals. Distance to the referral centre and the perceived costs of treatment were significant barriers to referral. Dentists valued the specialist's personal reputation and clinical skills more highly than academic status. Deficiencies in communication between primary and secondary care were highlighted. CONCLUSIONS: Increased resources are required to manage periodontal diseases within the NHS. There is a need for a periodontal referral service in the North East of England to improve accessibility to specialist care. This would appear to be most appropriately delivered by increased numbers of specialist practitioners.

Almost all five year disease free survivors are cured following rectal cancer surgery, but longer term follow-up detects some late local and systemic recurrences.

BACKGROUND: The necessity, timing and benefits of follow-up after rectal cancer surgery remain controversial, with two years traditionally considered adequate to detect most local recurrences. This unit has a policy of lifetime follow-up, and this paper investigates, at 23 years, the value of prolonged surveillance. METHOD: Six hundred and sixty consecutive patients undergoing surgery for rectal cancer were prospectively followed-up between 1978 and 2002, and local or systemic recurrence recorded. This analysis was performed on the 509/660 (76%) patients who underwent potentially curative surgery. RESULTS: Total mesorectal excision (TME) was performed in 422/509 (83%) patients, mesorectal transection in 78 (15%), and local excision in 9 (2%). Follow-up ranged from 1 to 23 years (mean = 9.7). Seven (1.4%) patients had local recurrence alone, 11 (2.2%) local plus systemic, and 86 (17%) systemic recurrence alone. Of the local recurrences 3 (17%) became evident within 1 year, 9 (50%) within 2 years, 16 (89%) within 5 years, and 2 (11%) presented after 5 years, at 5.6 and 5.8 years. Of the systemic recurrences 26 (27%) became evident within 1 year, 57 (59%) within 2 years, 93 (96%) within 5 years, and 4 (4%) presented after 5 years at 5.3, 5.3, 5.4 and 7.9 years. CONCLUSION: This long-term surveillance of patients undergoing curative surgery for rectal cancer demonstrates that most local and systemic recurrences occur within 5 years. Almost half occurred more than 2 years after surgery. However, those centres wishing to set standards of care, or evaluate current or new therapies in rectal cancer treatment, should be aware that unexpected late recurrences occasionally develop.

Generation of superoxide anion impairs histamine-induced increases in macromolecular efflux.

The first goal of this study was to determine the effect of generation of superoxide anion using pyrogallol on histamine-induced increases in macromolecular efflux. We used intravital microscopy and fluorescein isothiocyanate-dextran (FITC-dextran; MW 70K) to examine macromolecular extravazation from postcapillary venules in the hamster cheek pouch in response to histamine before and following topical application of vehicle or pyrogallol. Extravazation of macromolecules was quantitated by counting venular leaky sites. Histamine elicited reproducible increases in venular leaky sites before and during infusion of vehicle. In contrast, topical application of pyrogallol (0.5 mM) abolished histamine-induced increases in formation of venular leaky sites. Our second goal was to examine whether pyrogallol-induced inhibition of venular leaky site formation could be reversed by superoxide dismutase. Application of superoxide dismutase (300 U/ml) to the cheek pouch in the presence of pyrogallol restored histamine-induced increases in venular leaky sites. Thus, the generation of superoxide anion alters histamine-induced increases in macromolecular efflux. These results support the concept that disease states that produce oxidative stress may impair agonist-induced increases in microvascular permeability via inactivation of nitric oxide.