This thesis presents studies relating to effects of different macronutrients, predominantly fat and carbohydrate, on gastrointestinal motility, hormone release/suppression, appetite and energy intake in healthy subjects, and on symptom generation in patients with functional dyspepsia. The three broad areas that have been investigated in these studies are: (i) the effect of load, and duration, of small intestinal nutrient exposure on gastric motility, gastrointestinal hormone release/suppression, appetite and energy intake in healthy subjects, (ii) the dietary factors that may contribute to symptom generation in patients with functional dyspepsia, through analysis of diet diaries and acute nutrient challenges, and (iii) the effects of the herbal medication, Iberogast®, on gastric motility in healthy subjects. The ingestion of nutrients, triggers a number of gastrointestinal responses, including the modulation of antropyloroduodenal motility, gastrointestinal hormone release/suppression, and the suppression of appetite and energy intake, resulting in a slowing of gastric emptying to an average rate of 1 - 3 kcal/min, which is required for efficient nutrient digestion and absorption. Additionally, the rate at which glucose enters the small intestine influences postprandial glycaemia and incretin responses. These responses have been demonstrated in animals to be dependent on the length, and region, of the small intestine exposed to fat and glucose, however, this has not been directly investigated in humans. Functional dyspepsia is a clinical condition, characterised by chronic upper abdominal symptoms, such as nausea, bloating and early fullness, without a known cause, which affects approximately 11 - 29 % of the population. Many studies have reported that disturbed gastric motor activity may be the cause of these symptoms, but patients frequently experience symptoms following ingestion of food, and some patients report to eat smaller meals more frequently and avoid fatty and spicy foods. In addition, laboratory-based studies have indicated that functional dyspepsia patients may be hypersensitive to fat, but not carbohydrate. To date, the treatments used to reduce symptoms are frequently directed at the normalisation of gastroduodenal motility, using prokinetics. However, the beneficial effect of these drugs is relatively small and variable, and their adverse effects can be substantial. Herbal drug preparations have recently received considerable interest as an alternative treatment option in functional dyspepsia. A commercially available herbal preparation, Iberogast® which contains nine plant extracts, has been reported to improve upper abdominal symptoms in functional dyspepsia and to decrease fundic tone, increase antral contractility and decrease afferent nerve sensitivity in experimental animals. The effects of Iberogast® in the human gastrointestinal tract have not been investigated. The first three studies presented in this thesis have focused on the effects of delivering fat and glucose into the small intestine at different loads (Chapter 5, 6 and 7), lower, comparable to, and higher than gastric emptying normally occurs, and at different durations of infusion (but still at similar caloric loads - Chapter 5, fat only), on gastrointestinal motility, plasma hormone release/suppression, glycaemia, and energy intake in healthy male subjects. The study in Chapter 5 demonstrated that antral pressure waves and pressure wave sequences were suppressed, and basal pyloric pressure, isolated pyloric pressure waves, and plasma cholecystokinin and peptide YY stimulated, during both the low (1.33 kcal/min for 50 min: 67 kcal/min), and high (4 kcal/min for 50 min: 200 kcal), loads of lipid. The effect of the 4 kcal/min load was sustained so that the suppression of antral pressure waves and pressure wave sequences and increase in peptide YY remained evident after cessation of the infusion. The prolonged lipid infusion (1.33 kcal/min for 150 min: 200 kcal) suppressed antral pressure waves, stimulated cholecystokinin and peptide YY and basal pyloric pressure and tended to stimulate isolated pyloric pressure waves when compared with saline throughout the entire infusion period. These results indicate that both the load, and duration, of small intestinal lipid have an influence on antropyloroduodenal motility and patterns of cholecystokinin and peptide YY release. Chapter 6 demonstrated that lipid loads lower than gastric emptying normally occurs (0.25 kcal/min for 50 min: 12.5 kcal) transiently stimulated isolated pyloric pressure waves and cholecystokinin release and suppressed pressure wave sequences and hunger scores. Loads comparable to (1.5 kcal/min for 50 min: 75 kcal) and higher (4 kcal/min for 50 min: 200 kcal), than the normal rate of gastric emptying, were required to stimulate basal pyloric tone and peptide YY release and suppress antral and duodenal pressure waves. Only the 4 kcal/min load suppressed energy intake. The effects of lipid on all parameters, with the exception of hunger, were load-dependent. In addition, there were relationships between antropyloroduodenal motility and cholecystokinin and peptide YY concentrations with energy/food intake. The study in Chapter 7 demonstrated that loads of glucose lower than (1 kcal/min for 120 min: 120 kcal), comparable to (2 kcal/min for 120 min: 240 kcal) and higher than (4 kcal/min for 120 min: 480 kcal) the rate gastric emptying normally occurs, stimulated blood glucose, plasma insulin, glucagon-like peptide-1, glucose-dependent insulinotropic polypeptide and cholecystokinin concentrations and suppressed the number of antral pressure waves, 2 and 4 kcal/min loads were required for the suppression of duodenal pressure waves and pressure wave sequences and the stimulation of basal pyloric pressure and suppression of energy intake only after the 4 kcal/min loads. There were also relationships between glucagon-like peptide-1 and glucose-dependent insulinotropic peptide with basal pyloric tone, and food/energy intake with pyloric pressures. The studies presented in the subsequent three chapters investigated the contribution of dietary factors on the generation of symptoms in patients with functional dyspepsia when compared with healthy subjects (Chapter 8 and 9) and the effect of Iberogast® on motility in the healthy gastrointestinal tract (Chapter 10). The effects of equi-caloric high-carbohydrate vs. high-fat yoghurt preloads on symptom generation, plasma hormone concentrations, antral area and energy intake were compared between functional dyspepsia patients and healthy subjects (Chapter 8). Nausea and pain were greater in patients after the high-fat, when compared with high-carbohydrate and control, preloads and with healthy subjects. Discomfort was greater after all preloads in patients when compared with healthy subjects. Fasting cholecystokinin and stimulation of cholecystokinin by the high-fat preload were greater in patients, while fasting and postprandial peptide YY were lower in patients than in healthy subjects, with no differences in fasting, or postprandial, plasma ghrelin between patients and healthy subjects. Fasting antral area was greater in patients, with no differences postprandially between patients and healthy subjects. There were no differences in energy intake between the two groups. The relationship between the effect of dietary intake and eating behaviour over a 7-day period on the occurrence and severity of abdominal symptoms was compared between patients and healthy subjects (Chapter 9). The symptoms experienced by the patients included nausea, fullness discomfort, bloating and upper abdominal, and epigastric, pain, of a modest severity, which occurred within 30 min of eating. The number of “meals” ingested was significantly less in functional dyspepsia patients and there was a trend for total energy and fat intake to be less. The occurrence of these symptoms was also statistically related to the ingestion of fat and energy intake. The results of these studies indicate that diet, particularly the ingestion of fat, influences the development of symptoms in a subgroup of patients with functional dyspepsia. The study in Chapter 10 evaluated the effect of the herbal drug Iberogast® on gastric motility in the gastrointestinal tract. Iberogast® increased proximal gastric volume, increased antral pressure waves without affecting pyloric or duodenal pressures, and slightly increased the retention of liquid in the total stomach, but had no effect on gastric emptying of solids or intragastric distribution. These results demonstrate that Iberogast® affects gastric motility in humans, and the stimulation of gastric relaxation and antral motility may contribute to the reported therapeutic efficacy of Iberogast® in functional dyspepsia. The studies reported in this thesis provide new information about the regulation of gastric motility, hormone release/suppression, appetite and energy intake, by varying the loads of lipid and glucose infused into the small intestine in healthy subjects, which may have implications in patients with altered gastric motor functions, such as obese, type-2 diabetes and functional dyspepsia patients. In addition, studies in functional dyspepsia patients revealed that diet, in particular the ingestion of fat, contribute to the cause of their symptoms, and these findings may have important implications for the development of diet-based therapies for the treatment of functional dyspepsia. Furthermore, functional dyspepsia patients with impaired gastric relaxation and antral dysmotility may benefit from the effects of Iberogast® as demonstrated in the healthy gastrointestinal tract. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1331606 / Thesis (Ph.D.) - University of Adelaide, School of Medicine, 2008

<p>El propósito del presente estudio es comprobar la efectividad del aprendizaje de una segunda lengua en situaciones tanto naturales como formales en cuanto a la adquisición de la competencia socio-pragmática se refiere. Muchos son los estudios realizados sobre la enseñanza de lenguas extranjeras en el aula, pero pocos los que se han centrado en esta competencia. Es por ello que pretendemos profundizar en este campo mediante un análisis de los resultados de ambas formas de aprendizaje, el formal y el natural. Partimos de la creencia generalizada de que mediante estancias en países donde se habla la lengua estudiada se aprende mucho más y mejor, y defendemos la hipótesis de que, si bien el hecho de viajar beneficia en gran medida la adquisición de una lengua, no basta para que la adquisición sea satisfactoria, sino que ésta depende de la integración social que los aprendices logren durante estas visitas. Para comprobar nuestra hipótesis nos basamos en una batería de preguntas distribuidas tanto a estudiantes que hayan residido/visitado países de habla hispana como a los que no lo hayan hecho, así como a hablantes nativos de la lengua meta, con el fin de obtener muestras de la competencia socio-pragmática que se espera de los estudiantes tras su aprendizaje. Finalmente concluimos que serían las relaciones que se establecen con los hablantes nativos las que condicionan el éxito de las estancias en el extranjero, no el simple hecho de viajar.</p>

Introduction: Several national trials have demonstrated the efficacy of lifestyle interventions on decreasing the incidence of type 2 diabetes in adults with prediabetes. Behavior change pertaining to physical activity (PA) and diet were central to these lifestyle interventions; however it is likely a majority of adults with prediabetes are not currently meeting public health guidelines for PA and dietary intake. Little information is available on different influences of behavior central to prediabetes treatment. Given these findings, further investigation into potential influences on the efficacy of prediabetes service provision is warranted. Purpose: This dissertation aimed to explore prediabetes service provision to identify potential influences on PA and dietary intake in adults with prediabetes. Methods: The first study used Grounded Theory methodology to obtain opinions on necessary components of an optimal diabetes prevention program from health professionals (n=20) and adults with, or at high risk of, prediabetes (n=12). The second, third, and fourth studies involved individuals with prediabetes (N=232) in Northern Alberta, Canada. Participants completed a mailed survey assessing various demographic, health and behavior influences in August-September, 2008. Results: Data from Study 1 identified four influences on behavior change in adults with prediabetes: service provision, knowledge or confusion, motivational influences, and goal-setting. Potential strategies to increase effectiveness of prediabetes programs were also identified. In Study 2, individuals with prediabetes achieving PA guidelines (38%) reported higher physical and mental health-related quality of life compared to those not meeting PA guidelines. In Study 3, a number of preferences for PA and PA programming were identified. Activity status, health, and demographic variables all demonstrated significant influence on different PA preference variables. In Study 4, behavior-specific social cognitive theory constructs including self-efficacy, outcome expectations, and goal formation demonstrated significant associations with each other and PA, fat, and fibre intake. Conclusions: Evidence suggests it is possible to prevent or delay the progression of prediabetes to diabetes with small changes in body weight, physical activity and dietary intake. The results reported in this dissertation identified a number of factors that may influence potential success of a prediabetes program to promote behavior change and increase the public health impact of prediabetes prevention programs.

This investigation examined acute energy compensation and macronutrient intake in habitually active and sedentary, college-aged males, following an exercise session as compared to a resting (control) session, to see if habitually active males compensate intake better to an energy deficit incurred by exercise, than sedentary males. Participants were males, aged 18-30 years, of a normal percent body fat and body mass index, and exercised < 60 min per week (sedentary) or > 150 min per week (habitually active). Participants came in for two sessions: 1) 45 minutes of resting (control) and then eating an ad libitum meal; and 2) riding a cycle ergometer for 45 minutes (exercise) and then eating an ad libitum meal. Sessions were counterbalanced across participants. Energy and macronutrient intake were calculated for the meal and over the remaining part of the day. Sedentary individuals ate significantly less during the meal in the exercise session (which expended a mean of 453.5 kcals across both groups) as compared to the control session (934.8 + 222.0 kcals vs. 1073.9 + 470.3 kcals, p < 0.03), which demonstrated negative energy compensation (-30.6%). The habitually active group showed no significant difference in energy intake between sessions at the meal (1016.8 + 396.7 kcal [control] vs. 1105.6 + 389.2 kcal [exercise]). While the habitually active group showed no significant difference in intake at the meal, the slight increase in intake at the meal in the exercise session demonstrated some energy compensation (19.6%), which was significantly better (p < 0.03) than that in the sedentary group. No differences in macronutrient intake at the meal were found between the sessions. Over the day following the sessions, both groups reported a significant increase in energy intake after the exercise session as compared to the control session (1457.5 + 646.2 kcals vs. 1356.1 + 657.2 kcals, p < 0.04), with no difference in macronutrient intake between the sessions. These results indicate that, although complete acute compensation did not occur, the habitually active group acutely compensated intake significantly more so than the sedentary group, demonstrating better energy regulation ability.

<p>Observations of feeding behaviour of common guillemots, <em>Uria aalge</em>, in June 2002 at the island Stora Karlsö in the Baltic Sea proper, and measurements of morphology and energy density in the prey fish sprat, <em>Sprattus sprattus</em>, showed that fish delivered to chicks at present are shorter and weigh less than in the 1970s. Long lasting attending periods and a feeding rate of 4.6 feeds per day indicate that parents are feeding their chicks at a maximum rate. Because of a decline in the energy density in sprat (22.4 kJg^-1 dry weight) the daily energy intake of common guillemot chicks have declined noticeably. This could probably explain the observed decrease in fledging body weight of chicks through the 1990s. Baltic common guillemots do not seem to be able to select more energy-dense prey sizes or to switch to other prey species.</p>

The overall aim was to follow the development of nutritional status and its significance for general health status using an epiemiologic method in a representative population‐based selection of older individuals in two cohorts. The main focus was to prospectively examine the significance of demographic, social and medical factors and to establish a basis to investigate the possibilities of preventive measures. Methods: Five hundred and eighty‐three individuals (278 women and 305 men), 75 and 80 years old, when included, living in a municipality in Östergötland in Sweden, participated in this study. Data collection took place 2001‐2006 with one examination yearly. The examination included a single question regarding self‐perceived health demographical questions, different questionnaires in the areas of nutritional status, symptoms of depression, cognitive function, health‐related quality of life and well being and objective assessments such as anthropometrical, physical and biochemical measurements. Results: Fifty percent of the women (I) and 58% of the men (II) perceived themselves as healthy. Important factors for women’s health (I) at baseline were no or few symptoms of depression, better physical mobility and better physical health. Among men who perceived themselves as healthy (II) at baseline, important factors were better physical health, maintaining a social network and the ability to walk outdoors. After one year 69% of the women and 75% of the men still perceived themselves as healthy. Among those women (I) who perceived themselves as healthy after one year, better physical mobility and better physical health were still important, with the addition of less or no pain. Important predictors for preserving health among men (II) were no symptoms of depression and the ability to walk up and down stairs. The prevalence of risk for malnutrition (III) was 14.5% (n=84), among women 18.8% and men 10.6%. Risk factors for malnutrition at baseline were a lower TSF, lower handgrip strength and worse physical health according to the PGC MAI. The incidence was 7.6%‐16.2%, and was distributed equally among women and men over time. Predictors for developing malnutrition were lower self‐perceived health, increased number of symptoms of depression.  Especially men with symptoms of depression ran a higher risk. Reported energy intake (IV) was low in relation to the estimated requirement, on average 74% among women and 67% among men. Intake of vitamins A, D, E and folate was below the recommended intake and the same pattern was found over time. A smaller weight loss was found among women and men from baseline to Follow‐up 2. Conclusions: The experience of a good physical health was the only common factor for a good self‐perceived health among women and men. The highest risk for developing malnutrition was a combination of impaired self‐perceived health and increased number of symptoms of depression. Clinical implications: A combination of nutritional status, self‐perceived health and symptoms of depression can be a base for clinical judgement and can be used by different professionals in ealth and medical care and in home care service.

Sea water intake structures submerged in the surf zone are used to provide water for cooling processes in large facilities such as power plants and refineries. Structures submerged in the surf zone are subject to large forces from breaking waves. To study these forces induced from realistic sea state conditions, a physical model of an intake structure submerged in the wave breaking zone was constructed and subjected to a wide spectrum of regular and irregular waves. The model structure was designed in a manner so force measurement could be isolated to separate components of the structure. The data of peak forces on the structure was analyzed for correlations with varying irregular wave properties. Using the results of forcing on the structure from regular wave tests, drag and inertia coefficients for use in the Morison equation were determined for each separate component and configuration of the structure. These force coefficients were plotted against various wave properties to analyze correlations with wave conditions. Finally, the force coefficients for the structure were used with the Morison equation and current data from the experiments to successfully model forcing on the structure during irregular wave tests.

A series of experiments were conducted during 2005 and 2006 to evaluate five perennial grass species for forage yield and quality, steer performance and grazing capacity, animal intake, plant energy reserves and economic return under grazed conditions. In 1999, two 0.8 ha replicates each of Paddock meadow bromegrass (<i>Bromus riparius</i>Rehm.), Carlton smooth bromegrass (<i>Bromus inermis</i>Leyss.) and AC Knowles hybrid bromegrass (<i>B. riparius</i> x <i>B. inermis</i>) were seeded. In 2003, two 0.8 ha replicates each of AC Goliath crested wheatgrass (<i>Agropyron cristatum </i> (L.) Gaertn.), hybrid bromegrass, and Courtenay tall fescue (<i>Festuca arundinacea </i> Schreb.) were seeded. A long established stand of crested wheatgrass acted as the control pasture. For 2003 established pastures, AC Goliath crested wheatgrass (7515 kg ha-1) had greater (P<0.05) cumulative dry matter yield than hybrid bromegrass (3136 kg ha-1) during the 2005 grazing season. Average (2005-2006) crude protein (CP) was greatest (P<0.05) for hybrid and smooth bromegrass for 1999 established pastures at start and middle of period one. Control pastures had the greatest (P<0.05) neutral detergent fiber (NDF) mid-grazing period. Over 2 years, smooth bromegrass had greater acid detergent fiber (ADF) (P<0.05) than control pastures at the end of the grazing period one. Average (2005-2006) in vitro organic matter digestibility (IVOMD) was greatest for hybrid and meadow bromegrass (P<0.05) at the start of grazing period one. Control pastures (129 g kg-1) had lower CP levels at the start of the 2005-2006 (average) grazing period 1 (P<0.05) compared to species seeded in 2003. Control and hybrid bromegrass pastures had the greatest NDF and ADF levels at the start of grazing period 1 (2005-2006 average) while tall fescue pastures had the lowest (P<0.05) NDF and ADF levels. Over 2 years, control pastures had the lowest IVOMD at start of grazing (P<0.05). In 2006, hybrid and smooth bromegrass had greater etiolated re-growth than control pastures (P<0.05). In 2006, grazed plants seeded in 1999 had greater (P<0.05) etiolated re-growth than ungrazed plants. For 2003 seeded grasses, crested wheatgrass produced greater (P<0.05) etiolated re-growth than tall fescue and control pastures. Average daily gain was similar (P>0.05) for all 1999 and 2003 seeded grasses. Overall, bromegrasses seeded in 1999 produced greater animal grazing days (AGD) than control pastures (P<0.05). Total beef production (TBP) was greater (P<0.05) for hybrid and meadow bromegrass compared to the control. All species seeded in 2003 produced greater AGD (P<0.05) compared to the control. Crested wheatgrass produced greater (P<0.05) TBP than the control over both years of the study. The C33:C32 alkane ratio estimated greater DMI (P<0.05) for hybrid bromegrass (9.9 kg d-1) and control pastures (9.6 kg d-1) compared to crested wheatgrass (6.8 kg d-1) or tall fescue (6.8 kg d-1) during period 1 in 2006. Over 2 years, net return to labor, equity and personal draw was greater (P<0.05) for hybrid bromegrass ($91.24 ha-1) compared to the control (-$54.32 ha-1). For 2003 seeded pastures, all pastures generated positive returns over 2 years. Crested wheatgrass ($92.49 ha-1) had greater net return than control pastures (-$54.32 ha-1) (P<0.05). Finally, the results of this grazing study indicate beef producers can manage these grasses during the summer grazing season and maintain high levels of animal performance and pasture production. This study has demonstrated that bromegrasses, crested wheatgrass and tall fescue could work well in a complementary grazing system.

In order to elucidate the component(s) of yellow peas responsible for their health benefits, the effects of 10 or 20 g of isolated yellow pea protein (P10 and P20) or fibre (F10 and F20) on food intake (FI) at an ad libitum pizza meal served at 30 min (experiment 1) or 120 min (experiment 2), blood glucose (BG) and appetite in young healthy males (20-30 y) were investigated. In experiment 1, P20 suppressed FI compared to all other treatments and lowered cumulative FI (pizza meal kcal + treatment kcal) compared to F10. Protein treatments suppressed pre-meal (0-30 min) BG compared to control, whereas only P20 suppressed post-meal (50-120 min) BG. In experiment 2, there was no effect of treatment on any outcome measures. Thus, protein is the component responsible for the short-term effects of yellow peas on glycaemia and FI, but its second-meal effects diminish by 2 hours post-consumption.

The hypothesis that high multivitamin gestational (HV) diets affect the development of central serotonergic regulatory systems in female offspring, and that this is due to its high folic acid content, was investigated. Dams were fed the AIN-93G diet containing the recommended multivitamin mix (RV), 10-fold the RV amount (HV), or the RV diet with 10-fold the folic acid (Hfol). Serotonergic control of food intake and macronutrient selection was assessed by measuring long-term intake and selection, short-term intake and selection following injections of serotonin receptor agonists, and hypothalamic serotonin receptor expression. Offspring from Hfol dams selected more protein and were less responsive to agonist injections, but showed no altered serotonin receptor expression. In contrast, those born to HV fed dams were not different from the RV controls in any measure. In conclusion, the Hfol, but not HV gestational diet affects serotonergic regulation of food intake in female rat offspring.