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

Analysing the Impact of Digital Photography Projects on Student Engagement and Performance in a Higher Education Engineering Discipline

Developing and implementing engaging activities aligned with the learning outcomes of a module within a higher education programme is essential to successful teaching practice in the 21st century. Substantial research evidence indicates that student engagement plays a pivotal role in the academic performance and success of the student. The aim of this research is to compare student performance after adopting an alternative pedagogic approach utilising digital photography as a tool to engage the student in an engineering discipline. The activity was designed to promote student engagement by integrating digital photography, replicating authentic construction professional practice and focusing on images as a key means of communication and to aid the learning. Such strategies can promote student inclusion by eliminating literacy challenges associated with the traditional lecturing approach. A questionnaire to students revealed that those from a construction background perceived that they gained a deeper understanding of the subject matter and a richer learning experience, and advocated that more teachers on their programme should adopt a similar teaching strategy. A comparison of assessment results from two previous student cohorts (n=36 students) found that the alternative approach yielded superior exam performance. The careful planning and implementation of combined teaching strategies in a single engaging activity can deliver improved student performance without the need for additional material or financial resources

Immunological aspects of sport nutrition

Prolonged bouts of exercise and heavy training regimens are associated with depression of immune system functions that can increase the risk of picking up opportunistic infections such as the common cold and influenza. Some common sport nutrition practices including high-carbohydrate diets and carbohydrate ingestion during exercise, training with low-glycogen stores, intentional dieting for weight loss, ingestion of high-dose antioxidant supplements and protein ingestion post exercise may influence immune system status in athletes. In order to maintain robust immunity, athletes need to consume a well-balanced diet that is sufficient to meet their requirements for energy, carbohydrate, protein and micronutrients. Dietary deficiencies of protein and specific micronutrients are well known to be potential causes of immune dysfunction and an adequate intake of some essential minerals including iron and zinc and the vitamins A, D, E, B6 and B12 are important to maintain a healthy immune function. Vitamin D may be a particular concern as recent studies have emphasised its importance in limiting infection episode incidence and duration in both the general population and in athletes and many individuals exhibit inadequate vitamin D status during the winter months. There is only limited evidence that individual amino acids, β-glucans, herbal extracts and zinc are capable of boosting immunity or reducing infection risk in athletes. The ingestion of carbohydrate during exercise and daily consumption of probiotics, vitamin D3, bovine colostrum and plant polyphenol containing supplements or foodstuffs currently offer the best chance of success, particularly for those individuals who are prone to illness

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

Effects of intensified training and taper on immune function

Although resting immune function is not very different in athletes compared with non-athletes periods of intensified training (overreaching) in already well trained athletes can result in a depression of immunity in the resting state. Illness-prone athletes appear to have an altered cytokine response to antigen stimulation and exercise. Having low levels of salivary IgA secretion also makes athletes more susceptible to upper respiratory tract infections. Overtraining is associated with recurrent infections and immunodepression is common, but immune functions do not seem to be reliable markers of impending overtraining. There are several possible causes of the diminution of immune function associated with periods of heavy training. One mechanism may simply be the cumulative effects of repeated bouts of intense exercise (with or without tissue damage) with the consequent elevation of stress hormones, particularly glucocorticoids such as cortisol, causing temporary inhibition of TH-1 cytokines with a relative dampening of the cell-mediated response. When exercise is repeated frequently there may not be sufficient time for the immune system to recover fully. Tapering has been described as a gradual reduction in the training load which allows the recovery of physiological capacities that were impaired by previous intensive training and permits further training-induced adaptations to occur accompanied by competition performance enhancements. The majority of the studies that have examined the recovery of immunoendocrine responses during 1-3 week tapers in trained athletes have mainly reported enhanced performance, often accompanied by increased anabolic activity, reduced physiological stress and restoration of mucosal immunity and immune function.Quando se compara a função imune, em repouso, de atletas e não atletas, não se verificam grandes diferenças. Porém, períodos de treinamento intensificado ("overreaching") em atletas bem treinados podem induzir supressão da imunidade no estado de repouso. Os atletas com maior propensão para contrair doenças parecem apresentar uma resposta alterada de citocinas, tanto quando estas são estimuladas por antígenos, quanto em resposta ao exercício propriamente dito. Baixos níveis de secreção de IgA salivar também contribuem para tornar os atletas mais susceptíveis à infecções do trato respiratório superior. A síndrome do "overtraining" é associada a infecções recorrentes e a imunossupressão é comum; no entanto, marcadores da função imune não parecem ser suficientemente sensíveis ao "overtraining" eminente. Existem várias possíveis causas para a diminuição da função imune associadas com períodos de treinamento severo. Um possível mecanismo pode ser simplesmente, o efeito acumulativo de atividades e sessões repetidas de exercício intenso (com ou sem dano tecidual), com a consequente elevação dos hormônios de estresse, particularmente os glicocorticóides como o cortisol, causando assim, uma inibição temporária das citocinas de TH-1, com uma relativa atenuação da resposta imune celular. Quando o exercício é repetido frequentemente, pode não haver tempo suficiente para uma total recuperação do sistema imunológico. O "Tapering" tem sido descrito como uma gradual redução na carga de treinamento a qual permite a recuperação das capacidades fisiológicas, que por sua vez, foram afetadas pelo treinamento intensivo anterior, permitindo assim, que adaptações adicionais decorrentes do treinamento ocorram, acompanhadas pelo incremento do desempenho competitivo. A maioria dos estudos que investigaram a recuperação das respostas imuno-endócrinas em atletas durante uma a três semanas de "taper" tem registrado aumento do desempenho, frequentemente acompanhado pelo aumento da atividade anabólica, redução do estresse fisiológico e restabelecimento da imunidade das mucosas e da função imune

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

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

Acute and chronic effects of exercise on markers of mucosal immunity

Decreased secretion rate of salivary markers of mucosal immunity, and in particular salivary immunoglobulin A (s- IgA), have been implicated as risk factors for subsequent episodes of respiratory infection in athletes. IgA is the predominant Ig in mucosal secretions and acts with innate mucosal defences to provide the ‘first line of defence’ against pathogens and antigens presented at the mucosa. As well as summarising the evidence concerning the effects of acute exercise and longer-term intensive training on these markers of mucosal immunity, this review explores the factors that impact upon salivary responses to exercise, such as method of saliva collection, stimulation of saliva collection and the method of reporting s-IgA data. The influence of adequate hydration and nutritional supplementation during exercise as well as exercising in extreme environmental conditions on salivary responses is also explored. Finally, the possible mechanisms underlying the acute and longer-term of effects of exercise on salivary responses are examined, with particular emphasis on the potential role of the sympathetic nervous system and the expression and mobilisation of the polymeric Ig receptor

The in vitro Effects of Various Immunomodulatory Nutritional Compounds on Antigen-Stimulated Whole-Blood Culture Cytokine Production

Immunomodulators are substances that alter immune system via dynamic regulation of messenger molecules. It can be divided into immunostimulant and immunosuppressant. It can help to increase immunity of people with a low immune system, and also can help to normalize an overactive immune system. Aim of this study is to investigate the effects of in vitro exposure to low and high doses of several immunomodulators which include caffeine, kaloba and quercetin on antigen-stimulated whole blood culture cytokine production. Whole blood samples were taken from 5 healthy males (age: 32 ± 12 years; weight: 75.7 ± 6.1 kg; BMI: 24.3 ± 1.5 kg/m2) following an overnight fast with no vigorous activity during the preceding 24 h. The whole blood was then stimulated with 50 µl of 100 x diluted Pediacel vaccine and low or high dose of immunomodulators in the culture plate. After 20 h incubation (5% CO2, 37°C), it was analysed using the Evidence Investigator to determine the production of cytokines including IL-2, IL-4, IL-10, IFN-γ, and IL-1α. Caffeine and quercetin showed a tendency towards decrease cytokine production as the doses were increased. On the other hand, an upward trend was evident with kaloba, where a high dose of kaloba seemed to increase the cytokine production. In conclusion, we found that caffeine and quercetin have potential as immunosuppressant and kaloba as immunostimulant

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