Mucosal Defences, Antimicrobial Protein Concentrations and Risk of Infection in Athletes

The mucosal immune system functions as the first line of defence against pathogen invasion by preventing microbes adhering to mucosal surfaces and interrupting pathogen replication during transcytosis through epithelial cells. An important part of this defence mechanism is the secretion of antimicrobial proteins (AMPs) that have a broad range of activities against microorganisms including the direct inactivation of viruses. Some AMPs including lysozyme, lactoferrin, cathelicidin and defensins are produced by epithelial cells, neutrophils and macrophages in the lungs and are secreted into the biofilm covering the inner surface of the airways, thereby creating a barrier that is chemically lethal to microbes. Other proteins, including immunoglobulin (Ig)A, IgG and IgM are produced by lymphocytes and pass through the epithelial cells to enter the biofilm. In most human exercise studies, saliva has been used to examine the impact of acute or chronic exercise on mucosal immunity as it contains a similar cocktail of AMPs and may itself play a role in protection against pathogens that cause symptoms of upper respiratory tract infection. Short bouts of high intensity exercise result in reduced saliva flow rate but increased concentrations and/or secretion rates of AMPs. The changes in saliva IgA with strenuous acute exercise may reflect altered mobilisation of the polymeric Ig receptor due to increased sympathetic nervous system activation. Decreases in saliva volume reflect withdrawal of the inhibitory effects of the parasympathetic nervous system. Very prolonged bouts of continuous exercise commonly result in unchanged saliva flow rate and reduced concentrations and secretion rates of some AMPs (notably IgA). Periods of intensified training by athletes can also result in reduced concentrations and secretion rates of some AMPs including IgA and lactoferrin. The mechanisms underlying the chronic effect of exercise are unclear but may reflect modified IgA synthesis from local plasma cells and/or depletion of the available pool of the polymeric Ig receptor. An inhibitory effect of cortisol may be involved. In contrast, regular moderate physical activity is associated with elevated levels of IgA. Some, but not all, studies have reported negative associations between salivary IgA secretion and risk of respiratory illness. Thus, monitoring saliva IgA levels (and possibly other AMPs), with interpretation based on changes from the usual profile for the individual, can be a useful tool for athletes and coaches to highlight individuals who may be at risk of respiratory illness. Nutritional interventions that may influence AMP levels include probiotics, colostrum and vitamin D

Effects of Two Weeks of High-intensity Interval Training (HIIT) on Monocyte TLR2 and TLR4 Expression in High BMI Sedentary Men

International Journal of Exercise Science 6(1) : 81-90, 2013. Monocyte TLR expression has been shown to be reduced after a combination of aerobic and resistance exercise, but more studies considering the influences of different exercise intensities, type and duration on TLR expression are needed. Although there is an agreement about the importance of physical exercise, the minimal amount needed to improve health status is uncertain. Therefore, the aim of this study was to analyse the influence of 2 weeks of high-intensity intermittent exercise training on CD14+ monocyte TLR4 expression in a sedentary, high BMI population. As a secondary purpose, this study covers the influence of exercise on classical and pro-inflammatory monocytes and the TLR4 expression before and after a training period in these monocyte subsets. Six high-intensity interval training (HIIT) sessions over a 2 week period (three sessions per week) were completed by 11 sedentary participants (24 ± 5 years old). Blood samples were taken at the beginning and end of the training period for analysis of haematocrit, haemoglobin, total white blood cell (leukocyte), monocyte counts, monocyte CD14+ TLR4 expression and monocyte subsets. Two weeks of high-intensity intermittent exercise training increased VO2peak and total CD14+ monocyte TLR4 expression in a sedentary, high BMI population. There was no influence of training on the proportions of classical and pro-inflammatory monocyte subsets, but TLR4 expression in the majority of these monocyte subsets (apart from CD14++CD16+) was higher after the six training sessions

Spin-coating on nanoscale topography and phase separation of diblock copolymers

CRANN researchers are interested in mathematical modelling of all aspects of the process of spin-coating of diblock copolymers, with the aim of removing expensive trial and error design cycles. Of particular interest is the flow of the polymer during spin-coating, and also during the subsequent annealing process. Also of considerable interest is the chemical process of phase-separation and self-assembly of the diblock copolymer. Existing models in the literature rely heavily on computationally expensive Monte-Carlo simulation methods. The modelling work performed during the study group in summarized in this report. The report is split into four main sections, with discussion and suggestions for experiments in the concluding section. The content of the sections is as follows: Section 0.2: Mathematical modelling of spin-coating onto a flat substrate; no annealing considered. Section 0.3: Modelling of spin-coating onto a substrate with topography (i.e. trenches); no annealing considered. Section 0.4: Flow of polymer during annealing. Section 0.5: Models for self-assembly of polymers into nanostructures. Sections 0.2 to 0.4 are focussed on the fluid flow problems for the polymer, and go some way to providing useful answers to Problem 1. On the other hand, Problem 2 was found to be extremely challenging, and the efforts described in section 0.5 represent only a relatively modest impact on this problem

The Return of a River: The Willamette River, Oregon

2 p. Review produced for HC 441: Science Colloquium: Willamette River Environmental Health, Robert D. Clark Honors College, University of Oregon , Spring term, 2004. File contains the content of the Web site that was reviewed, captured Dec. 19, 2005Print copies of the reviewed title are available through the UO Libraries under the call numbers: Law Storage TD224.O7G57; and: SCA OrColl HD1694.O7G5

Integration of predictive-corrective incompressible SPH and Hodgkin-Huxley based models in the OpenWorm in silico model of C. elegans

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Influence of Prolonged Exercise and Hydration Status on Antigen-Stimulated Cytokine Production by Whole Blood Culture

Prolonged, strenuous exercise has been associated with a temporal depression of host defence, increasing susceptibility to upper respiratory tract illness (URTI). An elevated anti-inflammatory cytokine response to antigen challenge at rest has been reported as a risk factor for URTI. Chronic, strenuous exercise training appears to augment this anti-inflammatory response, with IL-10 release predicting URTI susceptibility in athletes. The purpose of this study was to determine the acute effects of a bout of prolonged exercise and hydration status on antigen-stimulated cytokine production. Twelve healthy males cycled for 120 minutes at 60% of maximal oxygen uptake on two occasions, once in a euhydrated state and once moderately hypohydrated. For the euhydrated trial, participants drank ad libitum during the 24 hours prior to the trial, and were provided with 250 mL water every 30 minutes during exercise. For the hypohydrated trial, fluid intake was restricted to 500 mL water during the 24 hours leading up to the trial, and no fluid was ingested during exercise. Blood samples were collected immediately before and after exercise, and following 2 hours of passive recovery. A full blood count was obtained, and plasma analysed for cortisol. In vitro antigen-stimulated cytokine production was determined from whole blood culture, using a multi-antigen vaccine as stimulant. Fluid restriction resulted in body mass loss of 1.3 ± 0.7 % and 3.9 ± 1.0 % before and after exercise, respectively. Exercise elicited a significant leukocytosis and elevated plasma cortisol, with no differences between trials. Post-exercise IL-10 production following stimulation was significantly higher than pre-exercise (p\u3c0.01). Both IL-4 (p\u3c0.05) and IL-10 (p\u3c0.01) release per lymphocyte were significantly increased 2 hours post-exercise compared with pre-exercise. Antigen-stimulated IL-6 production was significantly reduced 2 hours post-exercise (p\u3c0.05), an effect that remained significant when expressed per monocyte (p\u3c0.01). Although not quite reaching statistical significance, antigen-stimulated IFN-γ and IL-8 release tended to decrease following exercise, as did monocyte production of TNF-α. IL-1β and IL-2 production were not significantly altered by exercise. No significant effect of hydration status was observed for any of the measured variables. Prolonged exercise appears to result in augmented anti-inflammatory cytokine release in response to antigen challenge, possibly coupled with an acute suppression of pro-inflammatory cytokine production. These findings correspond with previous studies using mitogen or endotoxin as stimulant. Neither cytokine production nor plasma cortisol was affected by moderate hypohydration induced by fluid restriction for 24 hours prior to and during exercise

Influence of CMV/EBV Serostatus on Respiratory Infection Incidence During 4 Months of Winter Training in a Student Cohort of Endurance Athletes

The purpose of this study was to examine the influence of previous infection with cytomegalovirus (CMV) or Epstein Barr virus (EBV) on the incidence, severity and duration of upper respiratory tract illness (URTI) episodes in endurance athletes during a 4-month winter training period. Blood samples were obtained from 236 healthy subjects (186 males, 70 females) who were engaged in regular sports training (predominantly endurance-based activities such as running, cycling, swimming, triathlon, team games and racquet sports) at the start of the study period for CMV and EBV serostatus analysis. Their baseline characteristics were (mean ± SD) age: 21 ± 2 years, body mass: 73.5 ± 11.2 kg, height: 176.5 ± 9.3 cm, body mass index 23.6 ± 2.2 kg/m2. Weekly training and daily illness logs were kept. Self-reported weekly training duration averaged 9.6 ± 5.2 h/week and 4.0 ± 1.6% of the cohort experienced a URTI episode each week. Twenty-five percent of the subject cohort were CMV positive with a similar proportion in males (24%) and females (26%) whereas 84% of the subject cohort were EBV positive with a similar proportion in males (84%) and females (83%). In addition, 21% of the subject cohort were both CMV and EBV positive (CMV+EBV+) whereas 13% of the subject cohort had no prior CMV or EBV infection (CMV-EBV-). With regard to CMV/EBV serostatus, the results indicated that there was no difference in the proportion of subjects who presented with symptoms of infection between CMV/EBV positive and negative groups. Athletes with previous CMV infection had fewer URTI symptom days during the study period than those with no previous infection [mean and interquartile range (IQR), positives 2 (0-7) days, negatives 4 (1-9) days, P = 0.033] and EBV serostatus had no influence on URTI episode incidence, severity or duration. Moreover, we found that athletes with prior infection of both CMV and EBV had fewer URTI episodes and symptom days than athletes who were seronegative for both CMV and EBV [mean (IQR), URTI episodes: positives 0 (0-1), negatives 1 (0-2), P = 0.04; symptom days: positives 2 (0-7), negatives 8 (2-12), P = 0.01]. The reasons for this are still unclear but could be related to the previously reported elevated T cytotoxic cell response to exercise in individuals with positive CMV serostatus. Previous coinfection with CMV and EBV might promote protective immune surveillance to lower the risk of URTI

Influence of noise intensity on the spectrum of an oscillator

This paper investigates the influence of high-intensity noise on the correlation spectrum of a two-dimensional (2-D) nonlinear oscillator. An exact analytical solution for the correlation spectrum of this 2-D oscillator is provided. The analytical derivations are well suited for oscillators with white noise of any intensity, but computational constraints on the solution of the partial differential equation may make it impractical for cases where the number of state variables exceeds three. The spectral results predicted by our analytical method are verified by numerical simulations of the noisy oscillator in the time domain. We find that the peak of the oscillator spectrum shifts toward higher frequencies as the noise intensity is increased, as opposed to the fixed oscillation frequency predicted in the existing literature. This phenomenon does not appear to have been reported previously in the context of phase noise in oscillators

Self-Healing, Inflatable, Rigidizable Shelter

An inflatable, rigidizable shelter system was developed based on Rigi dization on Command (ROC) technology incorporating not only the requ ired low-stowage volume and lightweight character achieved from an i nflatable/rigidizable system, but also a self-healing foam system inc orporated between the rigidizable layers of the final structure to m inimize the damage caused by any punctures to the structure

The effect of 14 weeks of vitamin D3 supplementation on antimicrobial peptides and proteins in athletes

Heavy training is associated with increased respiratory infection risk and antimicrobial proteins are important in defence against oral and respiratory tract infections. We examined the effect of 14 weeks of vitamin D3 supplementation (5000 IU/day) on the resting plasma cathelicidin concentration and the salivary secretion rates of secretory immunoglobulin A (SIgA), cathelicidin, lactoferrin and lysozyme in athletes during a winter training period. Blood and saliva were obtained at the start of the study from 39 healthy men who were randomly allocated to vitamin D3 supplement or placebo. Blood samples were also collected at the end of the study; saliva samples were collected after 7 and 14 weeks. Plasma total 25(OH)D concentration increased by 130% in the vitamin D3 group and decreased by 43% in the placebo group (both P=0.001). The percentage change of plasma cathelicidin concentration in the vitamin D3 group was higher than in the placebo group (P=0.025). Only in the vitamin D3 group, the saliva SIgA and cathelicidin secretion rates increased over time (both P=0.03). A daily 5000 IU vitamin D3 supplement has a beneficial effect in up-regulating the expression of SIgA and cathelicidin in athletes during a winter training period which could improve resistance to respiratory infections