Effects of bovine colostrum supplementation on immune variables of highly-trained cyclists

The aim of this study was to investigate the influence of low-dose bovine colostrum protein concentrate (CPC) supplementation on selected immune variables in cyclists. Twenty-nine highly trained male road cyclists completed an initial 40-km time trial (TT(40)) and were then randomly assigned to either a supplement (n = 14, 10 g bovine CPC/day) or placebo group (n = 15, 10 g whey protein concentrate/day). After 5 wk of supplementation, the cyclists completed a second TT(40). They then completed 5 consecutive days of high-intensity training (HIT) that included a TT(40), followed by a final TT(40) in the following week. Venous blood and saliva samples were collected immediately before and after each TT(40), and upper respiratory illness symptoms were recorded over the experimental period. Compared with the placebo group, bovine CPC supplementation significantly increased preexercise serum soluble TNF receptor 1 during the HIT period (bovine CPC = 882 +/- 233 pg/ml, placebo = 468 +/- 139 pg/ml; P = 0.039). Supplementation also suppressed the postexercise decrease in cytotoxic/suppressor T cells during the HIT period (bovine CPC = -1.0 +/- 2.7%, placebo = -9.2 +/- 2.8%; P = 0.017) and during the following week (bovine CPC = 1.4 +/- 2.9%, placebo = -8.2 +/- 2.8%; P = 0.004). Bovine CPC supplementation prevented a postexercise decrease in serum IgG(2) concentration at the end of the HIT period (bovine CPC = 4.8 +/- 6.8%, P = 0.88; placebo = -9.7 +/- 6.9%, P = 0.013). There was a trend toward reduced incidence of upper respiratory illness symptoms in the bovine CPC group (P = 0.055). In summary, low-dose bovine CPC supplementation modulates immune parameters during normal training and after an acute period of intense exercise, which may have contributed to the trend toward reduced upper respiratory illness in the bovine CPC group.

Changes in neutrophil surface receptor expression, degranulation, and respiratory burst activity after moderate- and high-intensity exercise

Intense exercise stimulates the systemic release of a variety of factors that alter neutrophil surface receptor expression and functional activity. These alterations may influence resistance to infection after intense exercise. The aim of this study was to examine the influence of exercise intensity on neutrophil receptor expression, degranulation (measured by plasma and intracellular myeloperoxidase concentrations), and respiratory burst activity. Ten well-trained male runners ran on a treadmill for 60 min at 60% [moderate-intensity exercise (MI)] and 85% maximal oxygen consumption [high-intensity exercise (HI)]. Blood was drawn immediately before and after exercise and at 1 h postexercise. Immediately after HI, the expression of the neutrophil receptor CD16 was significantly below preexercise values (P < 0.01), whereas MI significantly reduced CD35 expression below preexercise values (P < 0.05). One hour after exercise at both intensities, there was a significant decline in CD11b expression (P < 0.05) and a further decrease in CD16 expression compared with preexercise values (P < 0.01). CD16 expression was lower 1 h after HI than 1 h after MI (P < 0.01). Immediately after HI, intracellular myeloperoxidase concentration was less than preexercise values (P < 0.01), whereas plasma myeloperoxidase concentration was greater (P < 0.01), indicating that HI stimulated neutrophil degranulation. Plasma myeloperoxidase concentration was higher immediately after HI than after MI (P < 0.01). Neutrophil respiratory burst activity increased after HI (P < 0.01). In summary, both MI and HI reduced neutrophil surface receptor expression. Although CD16 expression was reduced to a greater extent after HI, this reduction did not impair neutrophil degranulation and respiratory burst activity.

Plasma zinc and immune markers in runners in response to a moderate increase in training volume

Changes in plasma zinc concentration and markers of immune function were examined in a group of 10 male runners (n = 10) following a moderate increase in training over four weeks. Seven sedentary males acted as controls. Fasting blood samples were taken at rest, before (T0) and after (T4) four weeks of increased (+ 16 %) training and after two weeks of reduced (-31 %) training (T6). Blood was analysed for plasma zinc concentration, differential leucocyte counts, lymphocyte subpopulations and lymphocyte proliferation using incorporation of 3H-thymidine. The runners increased their training volume by 16 % over the four weeks. When compared with the nonathletes, the runners had lower concentrations of plasma zinc (p = 0.012), CD3 + (p = 0.042) and CD19 + lymphocytes (p = 0.010) over the four weeks. Lymphocyte proliferation in response to Concanavalin A stimulation was greater in the runners (p = 0.0090). Plasma zinc concentration and immune markers remained constant during the study. Plasma zinc concentration correlated with total leucocyte counts in the athletes at T6 (r = -0.72, p < 0.05) and with Pokeweed mitogen stimulation in the nonathletes at T6 (r = -0.92, p < 0.05). Therefore, athletes are unlikely to benefit from zinc supplementation during periods of moderately increased training volume.

Exercise-induced alterations in neutrophil degranulation and respiratory burst activity : possible mechanisms of action

Neutrophils constitute 50-60% of all circulating leukocytes; they present the first line of microbicidal defense and are involved in inflammatory responses. To examine immunocompetence in athletes, numerous studies have investigated the effects of exercise on the number of circulating neutrophils and their response to stimulation by chemotactic stimuli and activating factors. Exercise causes a biphasic increase in the number of neutrophils in the blood, arising from increases in catecholamine and cortisol concentrations. Moderate intensity exercise may enhance neutrophil respiratory burst activity, possibly through increases in the concentrations of growth hormone and the inflammatory cytokine IL-6. In contrast, intense or long duration exercise may suppress neutrophil degranulation and the production of reactive oxidants via elevated circulating concentrations of epinephrine (adrenaline) and cortisol. There is evidence of neutrophil degranulation and activation of the respiratory burst following exercise-induced muscle damage. In principle, improved responsiveness of neutrophils to stimulation following exercise of moderate intensity could mean that individuals participating in moderate exercise may have improved resistance to infection. Conversely, competitive athletes undertaking regular intense exercise may be at greater risk of contracting illness. However, there are limited data to support this concept. To elucidate the cellular mechanisms involved in the neutrophil responses to exercise, researchers have examined changes in the expression of cell membrane receptors, the production and release of reactive oxidants and more recently, calcium signaling. The investigation of possible modifications of other signal transduction events following exercise has not been possible because of current methodological limitations. At present, variation in exercise-induced alterations in neutrophil function appears to be due to differences in exercise protocols, training status, sampling points and laboratory assay techniques.

Intracellular trafficking and secretion of inflammatory cytokines

The secretion of cytokines by immune cells plays a significant role in determining the course of an inflammatory response. The levels and timing of each cytokine released are critical for mounting an effective but confined response, whereas excessive or dysregulated inflammation contributes to many diseases. Cytokines are both culprits and targets for effective treatments in some diseases. The multiple points and mechanisms that have evolved for cellular control of cytokine secretion highlight the potency of these mediators and the fine tuning required to manage inflammation. Cytokine production in cells is regulated by cell signaling, and at mRNA and protein synthesis levels. Thereafter, the intracellular transport pathways and molecular trafficking machinery have intricate and essential roles in dictating the release and activity of cytokines. The trafficking machinery and secretory (exocytic) pathways are complex and highly regulated in many cells, involving specialized membranes, molecules and organelles that enable these cells to deliver cytokines to often-distinct areas of the cell surface, in a timely manner. This review provides an overview of secretory pathways - both conventional and unconventional - and key families of trafficking machinery. The prevailing knowledge about the trafficking and secretion of a number of individual cytokines is also summarized. In conclusion, we present emerging concepts about the functional plasticity of secretory pathways and their modulation for controlling cytokines and inflammation.

Australian adolescents’ perceived school-based barriers and facilitators to engagement in physical activity

OBJECTIVE: School-aged youth spend a significant amount of time either in transit to and from school, or within school settings performing a range of varying learning-based activities. Adolescent physical activity has also been shown to increase the likelihood of maintaining physical activity throughout adulthood. The purpose of this study is to investigate adolescents’ perceived school-based barriers and facilitators to engagement in physical activity. METHODS: One-hundred and twenty four participants (38 males and 86 females) were recruited from two non-denominational same-sex private schools, in Brisbane, Australia. The mean age and standard deviation (SD) was 13.83 (0.56) and 14.40 (2.33) for males and females respectively. Participants responded to a series questions regarding perceived barriers and facilitators to engagement in physical activity. Quantitative data was analysed using descriptive statistics and frequency distributions, and qualitative data with thematic analysis. RESULTS: A total of 121 (97.6%) participants had complete data sets and were included in the analysis. School timetable (44.6%), homework (81.8%), and assessment (81.0%) were identified as the most prominent perceived factors, increasing the difficulty of physical activity engagement. Physical Education classes (71.9%) and school sport programs (80.2%) were identified as the most prominent perceived factors that facilitate engagement in physical activity. There was no significant gender effect. CONCLUSIONS: Each of the identified factors perceived by adolescent's as either barriers or facilitators to engagement in physical activity may be addressed by administrators at a school and government policy level. These may include strategies such as; increasing the assigned hours to physical education classes, providing additional extra-curricular sporting opportunities, and reviewing the time allocated to homework and assessment items. This may provide a simpler, low-cost solution to increasing youth physical activity, as opposed to contemporary higher-cost strategies utilising increased staff commitment, mass media, provision of equipment and counsellors and other health professionals.

The use of SMS messaging for physical activity promotion : preferences of Australian adolescents and their parents

OBJECTIVE: Recent increases in youth mobile phone ownership and usage may provide a unique and innovative opportunity for engagement by health promoters, via a familiar and immediately accessible medium. This study investigated adolescents’ and their parents’ preferences for promoting physical activity via means of SMS messaging. METHODS: Adolescents (36 males and 76 females) and their parents (37 males 75 females) were recruited from two non-denominational same-sex private schools, in Brisbane, Australia. The mean age and standard deviation (SD) for adolescents and parents was 14.03 (0.58) and 47.18 (4.65) respectively. Participants responded to a series of questions regarding mobile phone ownership, and preferences for physical activity, school-based physical activity programs, and programs invovling SMS messaging. Data analysis included descriptive statistics and frequency distributions. T-tests were employed to measure gender effect. RESULTS: Overall, 47 (42%) parents desired their child to be more physically active, and were interested for their child to participate in a school-based physical activity program. Of those parents, 16 (34%) parents were interested in their child participating in an SMS-based physical activity program, with 21 (45%) not interested, and 10 (21%) neutral. One hundred and four (95%) adolescents owned a mobile phone, with 84 (82%) of those adolescents wanting to be more physically active. Of those adolescents, 14 (17%) were interested in participating in an SMS-based physical activity program, with 40 (48%) not interested, and 30 (36%) neutral. There was no significant gender effect. CONCLUSIONS: Although SMS messaging may provide an innovative method for youth physical activity promotion, low levels of interest are concerning. These results differ from other studies utilising SMS messaging for the purpose of health promotion, where more positive feedback from participants were reported. A screening process to gauge interest prior to the implementation of any SMS-based health promotion program may prove invaluable toward the success of the program.

Passenger experience at airports : An activity-centred approach

This project has provided a new understanding of the passenger experience in Australian international airport departure terminals. A novel understanding of the passenger experience developed by observing the activities passengers carried out on their day of travel, and interviewing passengers and staff members. The development of the Taxonomy of Passenger Activities (TOPA) has been an important outcome of this research. It provides a new understanding of the airport passenger experience at departure. The Taxonomy of Passenger Activities identifies the activities that improve the experience of passengers and the processing efficiency of the airport terminal.

Effects of introducing an interactive teaching and learning activity (TLA) in the engineering classroom

This research study examines qualitatively and quantitatively the influence of introducing an activity in the traditional engineering classroom. It studies instances of active learning and its relationship with the student learning outcomes. The primary purpose of this study was to compare the learning outcomes of students who were involved in an active TLA with those students who were not, instead they learned under traditional teaching and studying approaches. I present the argument that the introduction of a TLA in class stimulates student engagement bringing enormous benefits to student learning. The outcomes of this study were measured using qualitative and quantitative data to evaluate the levels of student engagement, achievement and satisfaction in the terms of Intended Learning Outcomes (ILOs). Results indicate that students held positive attitude towards the activities in class and also, that a positive link between TLA, learning approach and learning outcome exist. It also provides insights about the potential benefits of active learning when compared with traditional, passive and teacher-centred methods of teaching & learning.

Mathematical modelling of tumour growth and interaction with host tissue and the immune system

In this thesis, three mathematical models describing the growth of solid tumour incorporating the host tissue and the immune system response are developed and investigated. The initial model describes the dynamics of the growing tumour and immune response before being extended in the second model by introducing a time-varying dendritic cell-based treatment strategy. Finally, in the third model, we present a mathematical model of a growing tumour using a hybrid cellular automata. These models can provide information to pre-experimental work to assist in designing more effective and efficient laboratory experiments related to tumour growth and interactions with the immune system and immunotherapy.

Hyperlipidemia impaired innate immune response to periodontal pathogen Porphyromonas gingivalis in apolipoprotein E knockout mice

A finely-tuned innate immune response plays a pivotal role in protecting host against bacterial invasion during periodontal disease progression. Hyperlipidemia has been suggested to exacerbate periodontal health condition. However, the underlying mechanism has not been addressed. In the present study, we investigated the effect of hyperlipidemia on innate immune responses to periodontal pathogen Porphyromonas gingivalis infection. Apolipoprotein E-deficient and wild-type mice at the age of 20 weeks were used for the study. Peritoneal macrophages were isolated and subsequently used for the study of viable P. gingivalis infection. ApoE−/− mice demonstrated inhibited iNOS production and impaired clearance of P. gingivalis in vitro and in vivo; furthermore, ApoE−/− mice displayed disrupted cytokine production pattern in response to P. gingivalis, with a decreased production of tumor necrosis factor-α, interleukin-6 (IL-6), IL-1β and monocyte chemotactic protein-1. Microarray data demonstrated that Toll-like receptor (TLR) and NOD-like receptor (NLR) pathway were altered in ApoE−/− mice macrophages; further analysis of pattern recognition receptors (PRRs) demonstrated that expression of triggering receptors on myeloid cells-1 (TREM-1), an amplifier of the TLR and NLR pathway, was decreased in ApoE−/− mice macrophages, leading to decreased recruitment of NF-κB onto the promoters of the TNF-α and IL-6. Our data suggest that in ApoE−/− mice hyperlipidemia disrupts the expression of PRRs, and cripples the host’s capability to generate sufficient innate immune response to P. gingivalis, which may facilitate immune evasion, subgingival colonization and establishment of P. gingivalis in the periodontal niche.

Perception and reality : meeting Australia’s physical activity guidelines for 12-18 year olds

Governments regularly publish empirically derived minimum physical activity (PA) guidelines for youth, in response to the ongoing trend of youth physical inactivity. The purpose of this investigation was to explore parents’ awareness of the national PA guidelines for youth, and adolescents’ and their parents’ perceptions of adolescent PA, and compare these to self-reported adolescent PA. A total of 115 adolescents (aged 12-14) and their parents completed questionnaire assessments. Parents responded to questions concerning their awareness of the national PA guidelines, and whether they believed their child to be sufficiently active. Adolescents completed the International Physical Activity Questionnaire for Adolescents, and questions concerning their perceived level of PA. Adolescents were deemed sufficiently active if they participated in an average of at least 60 minutes of moderate-to-vigorous PA each day. Overall, 104 (90.4%) adolescents and their parents had complete data sets and were included in the analysis. Of the 45 (43.3%) sufficiently and 59 (56.7%) insufficiently active adolescents, 42 (93%) and 41 (69.5%) respectively believed that they were active enough for good general health. Additionally, 41 (91.1%) parents of active and 44 (74.6%) parents of inactive adolescents either agreed or strongly agreed that their child participates in sufficient PA for good general health. Twenty-four (53.3%) parents of active adolescents were unaware of the national PA guidelines, with 10 (22.2%) neither aware or unaware, and 11 (24.4%) aware. Similar results were found for the parents of inactive adolescents with 31 (52.5%) unaware, 17 (28.8%) neither aware or unaware, and 11 (18.6%) aware. These results suggest that the youth PA guidelines are being inadequately received by both adolescents, and their parents. Opportunities to effectively communicate these guidelines such as embedment in curriculum for adolescents, or the dissemination of materials for parents, should be maximised by appropriate authorities.

Pre-service Physical Education teachers and concerns regarding their ability to successfully facilitate school-based physical activity promotion strategies

Regular physical activity (PA) in youth has numerous immediate and long-term health benefits. With several studies indicating low levels of youth PA globally, schools settings have become increasingly critical settings for youth health promotion strategies. The role of physical education (PE) teachers has long been considered central to the facilitation of such strategies. However, PE teachers have a selfreported lack of knowledge, skills, understanding, and competence to successfully implement these strategies. Tertiary education programs are fundamental to adequately preparing, and shaping the attitudes and philosophies of future PE teachers towards their involvement within these programs. The aim of this investigation was to explore the beliefs and perceptions of future secondary school PE teachers, regarding their potential roles in future school-based programs designed to promote student PA. Fifty-seven (21 males and 36 females) pre-service PE teachers completed a series of open-ended survey questions concerning their perceptions towards participating in school-based PA promotion programs both as preservice during practicum, and prospectively as practising teachers. Responses were analysed thematically. Participants responded both positively and enthusiastically to both questions. Concerns regarding time, and the intention or expectation to participate in such programs were also key themes for pre-service and practicing teacher participation respectively. Critically in this study, participants did not identify any limitations which may impact upon their ability to successfully promote youth PA in school settings. This may indicate that participants have misconceptions regarding their ability to fulfil this role, or conversely, the deficiency of current PE teachers regarding school-based PA promotion has been recognised by the tertiary institution, and addressed to adequately prepare its students. School-based PA promotion is an integral element of pre-service PE teacher education, and ongoing professional development of practicing PE teachers. This trend is expected to continue in the future, in order to address ongoing public health concerns.

Do adolescents ‘like’ the use of social networking and associated technologies for physical activity promotion?

Physical activity has been identified as a key behaviour in determining an individual’s health and functioning. Adolescent physical inactivity has been shown to track strongly through to adulthood. Interventions in youth to promote and increase physical activity have had mixed results. The significant rise over the past decade in time spent by adolescents performing social networking may provide a unique opportunity for health promoters to interact with adolescents through a familiar medium. The purpose of was study is to investigate the potential utility of social networking and associated technologies for the promotion of physical activity amongst adolescents. Participants were recruited from two nondenominational same-sex private schools, from high socioeconomic backgrounds in Brisbane, Australia. A total of 112 (90.3%) participants had complete data sets and were included in the analysis. Account ownership and rates of access to some social networking sites were high. However, a combination of a lack of interest and additional risks associated with social networking utilities, means that caution should be undertaken prior to the commencement of any intervention seeking to increase engagement in physical activities through these mediums. Student smart phone access and interest in smart phone applications for physical activity promotion purposes were moderate, and may provide opportunities for samples of adolescents from high socioeconomic backgrounds who are more likely to have access to appropriate technologies. As technology advances, the rate of smart phone ownership as opposed to overall phone ownership is likely to steadily increase over time. Access and use of information technology by children likely to continue to become more convenient. This makes smart phone applications as a means for physical activity promotion progressively more practical, and a promising future option.

Development and validation of a new self-report instrument for measuring sedentary behaviors and light-intensity physical activity in adults

Background Low levels of physical activity and high levels of sedentary behavior (SB) are major public health concerns. This study was designed to develop and validate the 7-day Sedentary (S) and Light Intensity Physical Activity (LIPA) Log (7-day SLIPA Log), a self-report measure of specific daily behaviors. Method To develop the log, 62 specific SB and LIPA behaviors were chosen from the Compendium of Physical Activities. Face-to-face interviews were conducted with 32 sedentary volunteers to identify domains and behaviors of SB and LIPA. To validate the log, a further 22 sedentary adults were recruited to wear the GT3X for 7 consecutive days and nights. Results Pearson correlations (r) between the 7-day SLIPA Log and GT3X were significant for sedentary (r =.86, p < 0.001), for LIPA (r =.80, p < 0.001). Lying and sitting postures were positively correlated with GT3X output (r =.60 and r =.64, p < 0.001, respectively). No significant correlation was found for standing posture (r =.14, p = 0.53).The kappa values between the 7-day SLIPA Log and GT3X variables ranged from 0.09–0.61, indicating poor to good agreement. Conclusion The 7-day SLIPA Log is a valid self-report measure of SB and LIPA in specific behavioral domains.