Dietetics, Nutrition and Biological Sciences
Permanent URI for this collectionhttps://eresearch.qmu.ac.uk/handle/20.500.12289/7187
Browse
8 results
Search Results
Item Role of eating frequency and macronutrient content of in-between-meal snacks incompliance with a low fatdietary advice in overweight men aged 25-50 years(Queen Margaret University, 2007) Zaveri, SwatiThe prevalence of obesity is increasing rapidly. Eating frequency has been shown to be inversely related to body weight status and appetite control. In addition, macronutrients have a role to play in appetite control, as protein has shown to be more satiating than either carbohydrate or fat. This dietary intervention study aimed to assess the impact of increasing daily eating frequency (EF), by providing either high carbohydrate (HC), high protein (HP), high fat (HF) snacks, or no snacks (control, C) on energy intake (EI), hunger ratings (HR), body weight status and metabolic parameters over 12 weeks in 59 healthy overweight to moderately obese Scottish men. Subjects were also followed up at 24 weeks (12 weeks post intervention). The HC (n = 14) and HF (n = 14) groups did not show a significant change in EF, HR, EI, body weight and % body fat at 6, 12 and 24 weeks compared to baseline. In contrast, the HP group (n = 18) showed a significant increase in the EF compared to HC group at 12 weeks, however, this did not result in a corresponding increase in EI, body weight or % body fat. Additionally, at 12 weeks, HP group tended to feel less hungry compared to baseline and HC group. However, the difference in the EF in HP group was not sustained after removing the under-reporters (URs). The C group (n = 13) showed a significant increase in HR at 12 weeks and an increase in % body fat at 24 weeks. There was no change in metabolic parameters in any study groups in the total sample. However, after removing the URs, there was a significant increase in total cholesterol level in HC group and a significant decrease in triglycerides level in control group. The study demonstrates that addition of extra energy, in the form of snacks, to the habitual diet may be compensated at the subsequent meals and does not result in an increase in EI and body weight. Including snacks that are healthy and of a reasonable portion size may help in maintaining a healthy diet and lifestyle.Item The inhibitory properties and mode of action of plant essential oils and fruit extracts on protozoan parasites(Queen Margaret University, 2008) Anthony, Jean-PaulThe main aims and objectives of this study was to determine if plant essential oils (PEOs) and polyphenol-rich fruit extracts (PRFEs) could reduce the viability of Giardia duodenalis trophozoites, Trypanosoma cruzi epimastigotes and Cryptospordium parvum oocysts in vitro. All PEOs tested reduced epimastigote and trophozoite viability at a concentration of 0.02% v/v, with titrations of the PEOs showing a concentration dependant decrease in viability. The minimum inhibitory concentrations (MICs) of PEOs demonstrated that myrtle and elemi oil were the most active PEOs (trophozoites = 0.005% v/v; epimastigotes = 0.00125% v/v) with the terpenes, α-pinene and limonene, constituents of these oils, being responsible for their action. Incubation of palmarosa oil and its terpene, geraniol, with C. parvum oocysts caused the almost complete excystation of oocysts (in the presence of increased temperature and time), with geranium oil and its terpene, citronellol, being nearly as effective. PRFEs reduce trophozoite viability, with 4 members of the Rosaceae Family causing complete reduction at 167 μg ml-1, possibly through their ellagitannin content. Cloudberry extract was found to have an MIC comparable to the drug metronidazole (67 μg ml-1). The historical use of blueberries for the treatment of diarrhoeal diseases was demonstrated by the ability of blueberry PRFE, pressed juice and drink to kill trophozoites. Protein expression was both inhibited and upregulated in several proteins in whole cell lysates of PEO treated trophozoites, indicating a supplemental intracellular mode of action. Both PEOs and PRFEs cause morphological changes to epimastigotes and trophozoites through flagellar truncation and internalisation, swelling and rounding of the cell body, cytoplasmic condensation and the formation of large membrane protrusions. These indicate an action on the membrane itself with possible changes in osmoregulation. Both PEOs and PRFEs can be considered to be candidates for novel drug discovery for the treatments of cryptosporidiosis, giardiasis and American trypanosomiasis.Item Consumer use of the nutritional label on food packages: a cognitive task analysis(Queen Margaret University, Edinburgh, 2000) Higginson, Catherine SusanItem The acute and long-term effects of 3,4- methylenedioxymethamphetamine (MDMA; 'ecstasy') upon cerebral and cerebrovascular serotonergic processes.(Queen Margaret University, 2004) Ferrington, LindaThe amphetamine derivative 3,4,-methylenedioxymethamphetamine (MDMA; Ecstasy) is a recreational drug of abuse, particularly popular among young people with whom it has formed a well-established sub-culture. MDMA is popular for its euphoria-inducing and mild stimulant properties and its popularity continues to rise despite a number of well-publicised cases of MDMA-associated fatalities and evidence of MDMA-induced acute toxicity. MDMA is known to produce an acute efflux of serotonin (5-HT) release in the brains of experimental animals, in which a marked behavioural response is also demonstrated. In the long-term MDMA causes specific neurotoxic damage to serotonergic nerve terminals, a phenomenon which is not demonstrated in other neurotransmitters. MDMA use has been associated with long-term adverse effects on both psychological and physiological health and this may represent a major public health problem given the 2 million people who use the drug in the UK alone. However, there is a perceived imbalance between the relative number of those who use MDMA and the serious adverse effects of the drug and it is possible that these may occur in a more susceptible sub-population of users. This thesis involves in vivo work using the Dark Agouti (DA) rat strain which is known to be more susceptible to MDMA and which may therefore provide an insight in this more susceptible sub-population of human MDMA users. The data presented in this thesis demonstrate that a single exposure to MDMA (15mg.kg-1) has a significal effect upon local cerebral glucose utilisation (LCMRglu) and local cerebral blood flow (LCBF) in DA rats both acutely and in the longer-term. This work demonstrates that this single dose of MDMA is neurotoxic to serotonergic neurons, inducing up to 80% depletion of serotonergic nerve terminals 6 weeks later. Furthermore, data generated from pharmacological challenges upon animals treated with MDMA 6 weeks earlier demonstrates the existence of compensatory mechanisms which act to normalise LCMRglu and LCBF, despite the persistence of serotonergic depletion. Thus this thesis extends the currently available information regarding acute and long-term effects of MDMA in a vulnerable sub-population of users and also proposes potential theories for the mechanisms of action by which pharmacological compensation for these long-term effects of MDMA-induced neurotoxicity may occur. In addition this thesis examines the effects of previous exposure to MDMA upon physiological challenges that might realistically be encountered by human users of the drug. The nature of MDMA-induced neurotoxicity suggests that human users of MDMA may suffer from untreatable chronic psychosis, and this thesis lends support to the view that currently available first line anti-depressant therapies may not be useful in the treatment of this sub-section of the population.Item The effects of Hypoxia on neuronal cell signalling(Queen Margaret University, 2009) Ibegbu, AugustineHypoxia adversely affects cells and tissues, and neuronal cells in particular have been shown to be more susceptible to the injurious effects of hypoxia i.e. they may begin to die when oxygen supply is reduced or completely eliminated. Cannabinoid (CB1) receptor and opioid (μ, δ and κ) receptor agonists have been shown to elicit several central nervous system (CNS) effects, mediated via G protein-coupled receptors. The aim of the research presented in this thesis was to study the effect of hypoxia on neuronal cell signalling and the consequent neuroprotectant effects of cannabinoid and opioid receptor agonists against hypoxia in the rat cortical neuronal cell line (B50) in culture. The B50 cells cultured in hypoxic conditions were treated and concurrently cultured with cannabinoid and opioid receptor agonists to determine the effects of these drugs on hypoxia-induced changes using downstream signalling activities such as cellular morphogenesis, growth, proliferation, differentiation, lactate dehydrogenase (LDH) leakage, second messenger (cAMP) and extracellular signalregulated kinases (ERK1/2) quantification, to assess the level of cellular damage and injury, repair and protection. Cortical B50 cells were cultured in either a normal incubator (21%O2; 5% CO2) as the normoxic control group, or a hypoxic incubator (5%O2; 5% CO2) as the experimental group. Three cannabinoid agonists [Win55,212- 2 mesylate (Win), anandamide or arachidonoylethanolamide (AEA), and 2- arachidonylglycerol (2-AG)] and three opioid agonists [DAMGO (μ), DSLET (δ) and ICI-199,441 hydrochloride (κ)], were selected and administered to the cells as treatment group for 48 hours after 48 hours of initial culture for a total of 96 hours of culture and pre-treatment group treated at 0 hour for a total of 96 hours in hypoxic conditions at concentrations of 10nM, 50nM and 100nM for cannabinoid agonists, and 10μM, 50μM and 100μM for opioid agonists. Neuronal viability, proliferation, differentiation and second messenger activity were assessed using morphological same-field assessment, LDH leakage, cellular proliferation assay, second messenger (cAMP) assay, and phospho-ERK1 & 2 assay and dibutyryl cyclic adenosine monophosphate (DbcAMP) induced differentiation method. Levels of G-protein coupled receptor (cannabinoid, CB1 and mu opioid, MOR) mRNAs were assessed using the RT-PCR method. The results showed that hypoxia induced a 4-fold increase in LDH leakage from B50 cells cultured in hypoxia when compared to the cells xxviii cultured in normoxic conditions (440% versus 100%, respectively; p<0.05). Cannabinoid receptor agonist treatment was able to reduce the LDH release in hypoxic cells to between 2-to 4-folds: 100nM AEA (69%), 100nM 2-AG (103%) and 10nM Win (217%), when compared to untreated hypoxic B50 cells (440% versus cannabinoid treated; p<0.05). The results of opioid administration showed a 3-fold decrease in the level of LDH leakage in B50 cells cultured in hypoxia when compared to untreated hypoxic cells (587%). The results of hypoxic treated B50 cells with opioid agonists are 100μM ICI-199,441 (318%); 50μM DSLET (339%) and 50μM DAMGO (352%) (p<0.05; untreated hypoxia versus opioid treated). The result of cAMP quantification in B50 cells in culture showed a reduction in cAMP concentration in untreated hypoxic B50 cells when compared to normoxic cells (0.7 pmol/ml versus 3.0 pmol/ml; p<0.05). Cannabinoid treated hypoxic cells showed increases in cAMP concentration: 2-AG 10nM (3.5 pmol/ml), 50nM (3.1 pmol/ml) and 100nM (0.9 pmol/ml), (p<0.05; Cannabinoid treated versus hypoxia untreated). The cAMP concentration in B50 cells treated in hypoxia with opioid agonist, ICI 199,441 hydrochloride, was significantly increased when compared to untreated hypoxic B50 cells (0.7 pmol/ml). The treatment with ICI 199,441 hydrochloride are 10μM (10.0 pmol/ml), 50μM (3.15 pmol/ml) and 100μM (1.15 pmol/ml), (p<0.05; opioid treated versus hypoxia untreated). The result of phospho-ERK1&2 assay in B50 cells showed decrease in phospho-ERK1&2 in untreated hypoxic cells when compared to normoxic untreated cells (6.0 units/ml versus 87.0 units/ml; p<0.05). The result of cannabinoid treated hypoxic cells showed increases in phospho-ERK1&2 when compared with the hypoxic untreated B50 cells: Win 10nM (98 units/ml), Win 100nM (27 units/ml), AEA 10nM (62 units/ml), AEA 100nM (60.5 units/ml), 2-AG 10nM (45 units/ml) and 2-AG 100nM (68 units/ml) (cannabinoid treated versus untreated hypoxia; p<0.05). The phospho-ERK1&2 in hypoxic B50 cells treated with opioid showed increase with DAMGO 10μM (22 units/ml), DSLET 10μM (16 units/ml) and ICI 199,441 hydrochloride 10μM (23.5 units/ml) (P<0.05; opioid treated versus hypoxia untreated). The result showed a decrease in cellular proliferation in untreated hypoxic cells when compared to the normoxic cells (7x106 cells/ml versus 20x106 cells/ml; p<0.05), while cannabinoid and opioid treatments was able to increase cell proliferation in hypoxic treated cells with: Win 10nM (11x106 cells/ml), AEA 100nM (12x106 cells/ml) and 2-AG 100nM (13.8x106 cells/ml), DAMGO 10μM (16x106 cells/ml), DSLET 10μM (20x106 cells/ml) and ICI xxix 199,441 100μM (21.5x106 cells/ml) when compared to hypoxic untreated cells (7x106 cells/ml) (hypoxia untreated versus hypoxia treated; p<0.05). Some of these changes were shown to be concentration-dependent between the normal and hypoxic B50 neurons, and between treated and untreated hypoxic B50 cells in culture, while the CB1 and MOR mRNA levels showed no appreciable change. The results show that B50 neuronal cells are susceptible to damage and injurious effects of hypoxia, as are most brain cells, while the results of the administration of cannabinoid and opioid agonists suggest that these agents have some potential therapeutic and protective benefits in the treatment and prevention of hypoxia-induced toxicity in neuronal B50 cells in culture. This could be of potential benefit in the treatment and protection against hypoxia-related neurodegenerative diseases and disorders such as stroke, dementias, ageing, Alzheimer’s and Parkinson’s diseases.Item Integrating components of energy intake in impaired glucose tolerant and type 2 diabetic populations(Queen Margaret University, 2008) Sommerville, JillObjective - During feeding there is an integrated 'whole body' response which endeavours to maintain energy homeostasis. The integrated response consists of sensory, postingestive, postabsorptive and cognitive feedback which exerts control over ingestive behaviour. It is accepted that when an imbalance in this integrated response occurs and may promote an increased fat mass and ultimately can lead to obesity which is known to play an important role in the development of IGT and type 2 diabetes. This study investigated the integrated responses of a test meal to determine any differences between IGT, type 2 diabetics and controls in their integrated response mechanisms. This knowledge may be important in both predicting the onset of these diseases and in the treatment of them. Research Design and Methods - IGT and type 2 diabetics with a BMI greater than 30 and were recruited together with a group of healthy controls. The study assessed habitual energy intakes and energy expenditure in all groups. All participants' height, weight, BMI and WHR were measured. A taste test assessed the sensory component of food intake. The metabolic response and parallel changes in appetite to the meal were recorded at baseline and at 15, 30, 60, 90 and 120 minutes. Results - Control participants had significantly lower weight (p<0.01), BMI (p<0.01), waist (p<0.01) and hip (p<0.01) measurements compared to IGT and the type 2 diabetic groups. Habitual diet diaries indicated a lower sugar intake in the type 2 diabetic group compared with IGT and control groups. Percentage protein intake was significantly lower in control participants (14.4%, p<0.05) compared to IGT (17.2%) and type 2 diabetics (18.5%). Activity diaries highlighted an indication of increased strenuous/physical activity in the control participants compared to IGT participants however, this was not statistically significant. The control group showed greater sensitivity to PROP followed by type 2 diabetics and then IGT participants (p<0.05). Throughout the study the control participants rated themselves the most hungry compared to IGT (p<0.05) and type 2 diabetics (p<0.01) respectively and controls were also the least satiated (p<0.05). There was no difference in fullness ratings. Control participants rated prospective consumption the highest compared to IGT and then type 2 diabetics (p<0.05) respectively. The differences in EE measured by calorimetry when normalised for body weight indicated that IGT (p<0.01) and type 2 diabetic participants (p<0.01) had significantly lower EE than control participants. CHO oxidation rates were significantly lower in IGT and type 2 diabetics (p<0.05). Investigating the blood parameters showed no differences in plasma ghrelin responses, that IGT participants had the highest overall plasma glucose (p<0.01) and insulin (p<0.05) responses. Conclusions - It is clear that there are subtle differences in the pathways of energy balance in IGT and type 2 diabetics compared to controls; including sensitivity to taste, subjective feelings of appetite, EE, oxidation rates and differing blood parameters. Taste appears to be an important contributor to the sensory control of food intake and is associated with an increased sugar intake. Furthermore, differences between IGT and type 2 diabetics demonstrate that the degree of management of the disease can influence the effectiveness of the metabolic pathways controlling food intake. It is not clear which component is the most influential in the control of food intake and it is likely that the synergistic effects are what potentiate the diseases and make them difficult to combat.Item Talk about homeopathy: discursive strategies as ways to continually marginalise homeopathy from mainstream acceptance(Queen Margaret University, 2009) Campbell, CraigTraditionally, quantifiable research into homeopathy has largely focused on its effectiveness compared to forms of mainstream medicine. The effect of such comparisons is that homeopathy is commonly constructed as not being demonstrably effective. It becomes discredited, demarcated and downgraded as an alternative 'type' of practice, subsequently marginalised in terms of mainstream acceptance. Qualitative studies concerned with homeopathy and focusing on notions of personal credibility, demarcation and the marginal are primarily concerned with practitioners' perspectives, where views are taken for granted and regarded as representative of accurate events. Thus, no study has focused on and investigated social constructions of homeopathic practice derived from practitioners, and their patients, in the semi-structured interview and in the context of the homeopathic consultation. Here, I identify and fill a gap in the literature which is currently under-represented. The corpus of twenty practitioners, seventeen patients and five homeopathic consultations drawn from interview and consultation contexts were recorded and subsequently transcribed verbatim. The innovative analytical framework is informed by discursive psychology perspectives that focus on accounts as action. Discourse analysis (DA) led to new, original and significant findings about how interpersonal experiences in relation to homeopathic practice are contingently formulated and constituted in interaction and configured over broader discourses. The analytical chapters show how talk about homeopathy is presented via four discursive strategies: by using the communicative competencies and descriptions they do, the participants' factual accounts function to enhance their own individual credibility and that of their practices, defend their practices and attend to the notion of personal accountability as a discursive practice. For those advocates for homeopathy, managing their personal credibility is accomplished only through sensitive ways of accounting. This reflects the way in which homeopathic practice is located in a culture of scepticism, as an alternative, contested and controversial 'type' of practice positioned on the fringe of the modern medical market. Demonstrating an understanding of homeopathy and their expectations of it as a form of treatment, participants draw upon dichotomised categories attributed to notions of mainstream medicine and homeopathy, combined with various discursive devices to add persuasiveness to their descriptions. Overall, the originality of the research lies in the application of the innovative interactional DA framework, its broad range of participants and unique findings from within the field of homeopathy. With several implications, it forms a unique interdisciplinary, theoretical, and methodological contribution to the DA literature. It has practical implications for future policy makers, in the education and training of practitioners, and offers ways to approach future research in homeopathic encounters and in parallel health-related encounters such as other CAM therapies, Myalgic Encephalomyelitis or Chronic Fatigue Syndrome and Attention-Deficit Hyperactivity Disorder. Notably, the transferability of the findings has wider implications for the understanding of other contested, controversial and new medical practices in the ways that mainstream medicine is the taken-for-granted, accepted yardstick for practice. In making this distinction, the paradoxical boundaries of what is and what is not acceptable is seen as a central issue to members' mutually intelligible sense-making practices in everyday medical encounters.Item An evaluation of the impact of introducing a breakfast club on nutritional status and cognitive function in lower social class primary school children(Queen Margaret University, 2005) Mehrotra, S.Breakfast has been shown to increase the supply of glucose to the brain which improves short-term memory. On waking hepatic glycogenolysis is the major buffer against short-term (12-18 hrs) fasting. The higher ratio of brain weight to liver weight in the child (1.4 - 1.6 versus 0.73 for the adult) and the 50% greater metabolic rate per unit brain weight in the child, places a greater demand on the child's glycogenic stores during a short fast as compared to the adult. Few school breakfast studies have examined the effect of different breakfasts on cognitive performance. This study investigated the nutritional differences of a habitual breakfast consumed at hom (NBC) and breakfast served at a breakfast club in (BC) school and the effect of these breakfasts on cognitive performance. Subjects were primary school children aged 7-11 years old in Scotland. When baseline cognitive performance scores were compared to scored at data collections 2,3 and 4 there were more significantly pronounced improvements for the NBC group than the BC group (p < 0.001). There were significantly greater numbers of children eating a cooked breakfast in the BC group and significantly higher numbers of children eating a cereal breakfast in the NBC group. As a result breakfasts of the BC group were higher in fat (MUFA and PUFA) (p < 0.01) and lower in percentage energy from carbohydrate than the NBC group. Positive correlations existed between percentage energy from carbohydrate and percentage energy from starch and cognitive test performance (p < 0.01). This suggests that a breakfast higher in % energy from carbohydrate such as a cereal breakfast benefits short-term memory, by supplying the brain with readily available supply of glucose it's primary and preferred fuel. This results of this research provide evidence for the requirement of guidelines to ensure that breakfasts served at school will both assist learning in morning lessons and be in-line with healthy eating recommendations.