Dissertations / Theses: 'Metabolic Aspects'

1

Svensson, Maria. "Metabolic aspects on diabetic nephropathy." Doctoral thesis, Umeå University, Public Health and Clinical Medicine, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-79.

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Diabetic nephropathy (DN) is associated with morbidity and mortality due to cardiovascular disease and renal failure. This study focused on the impact of glycemic control on the development of DN and the metabolic consequences of DN. The euglycemic hyperinsulinemic clamp technique was used to assess insulin sensitivity and insulin clearance. Two different registries, the Diabetes Incidence Study in Sweden (DISS) and the Swedish Childhood Diabetes Registry, as well as questionnaires and data from medical records were used to study diabetic complications in population-based cohorts.

Microalbuminuria is an early marker of DN and may also be associated with impaired insulin sensitiv-ity in diabetic and non-diabetic subjects. We studied the relationship between insulin sensitivity and the degree of albuminuria in patients with type 1 diabetes and micro- or macroalbuminuria but normal glomerular filtration rate (GFR). We did not find a direct quantitative association between the degree of albuminuria and insulin resistance, arguing against a cause-effect relationship.

With progression of DN, a decline in GFR is seen. Patients with severe renal failure have both im-paired insulin sensitivity and insulin clearance. We studied insulin sensitivity and insulin clearance in type 1 diabetes patients with three different degrees of renal involvement (none, only albuminuria, and slightly reduced GFR, ~40-70 ml/min/1.73 m2, respectively). A clear reduction in insulin sensitivity in vivo, but not in insulin clearance, was seen in the group with reduced GFR, and concomitant changes in the levels of PTH, IGF-1, IL-6 and TNF-α were found. In parallel, cellular insulin sensitivity and insulin degradation were examined in vitro, in subcutaneous fat cells but no differences were found between the three groups of patients.

To study the occurrence of renal involvement in patients with modern diabetes treatment we moni-tored a cohort of young adults from the DISS-registry with onset of diabetes in 1987-88 at age 15-34 years. We found that ~7% of the patients had signs of renal involvement, i.e. incipient nephropathy (5%) and overt nephropathy (2%), after a median follow-up of ~9 years and the strongest risk markers were poor glycemic control (HbA1c) and high blood pressure. Patients with type 2 diabetes were most prone to have renal involvement in this age group.

Retrospectively, we studied 94 patients diagnosed with type 1 diabetes in 1981-1992 at age 0-14 years at the Umeå University Hospital. Incipient nephropathy and background retinopathy occurred in 18 and 45%, respectively, of the patients, during ~12 years of follow-up. Glycemic control, also during the first five years of diabetes, was a strong risk marker. Young age at onset of diabetes prolonged the time to development of microvascular complications.

Conclusion: Despite modern diabetes treatment some patients with diabetes develop renal involvement within the first ten years. Inadequate glycemic control, also early in the disease, is a risk marker as well as type 2 diabetes and high blood pressure. In patients with type 1 diabetes and diabetic neph-ropathy a slightly reduced GFR, but not albuminuria, is associated with insulin resistance. Concomi-tant changes in insulin-antagonistic hormones and cytokines may be involved.

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2

Small, J. R. "Theoretical aspects of metabolic control." Thesis, Oxford Brookes University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382208.

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3

Gauna, Carlotta. "Metabolic aspects of the ghrelin system." [S.l.] : Rotterdam : [The Author] ; Erasmus University [Host], 2007. http://hdl.handle.net/1765/10528.

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Yasmin, Ephia. "Metabolic aspects of polycystic ovary syndrome." Thesis, University of Leeds, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.545722.

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Riley, Marshall S. "Metabolic aspects of chronic cardiac failure." Thesis, Queen's University Belfast, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335264.

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6

Wardle, Catherine A. "Metabolic aspects of the hypoxic heart." Thesis, University of Edinburgh, 1990. http://hdl.handle.net/1842/20278.

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Coronary heart disease is a major cause of death in Western society. Many studies have demonstrated the importance of lipid metabolism in the deterioration in cardiac function and the development of lethal arrhythmias during ischaemia. It has been suggested that a TAG-NEFA (triacylglycerol - non-esterified fatty acid) 'wasteful' cycle exists in the ischaemic heart and that increased operation of the cycle depletes ATP (adenosine triphosphate) supplies for the energy dependent ion pumps, disturbs membrane potentials and therefore causes arrhythmias. The aim of this thesis was to quantify energy wastage due to the operation of the TAG-NEFA cycle in the heart during oxygen deprivation. The hypoxic, isolated, perfused rat heart was used as the experimental model. Cannulation of the pulmonary artery allowed anaerobic sampling of coronary effluent for measurement of blood gases, and therefore calculation of oxygen uptake. Glycerol release was used as an index of TAG breakdown. Lactate production and tissue concentrations of ATP, CP (creatine phosphate), glycogen, α-glycerophosphate, glycerol and TAG were measured. The rate of TAG-NEFA cycling could therefore be calculated. The influence of severity of hypoxia on the rate of TAG-NEFA cycling was studied. A positive correlation between severity of hypoxia and energy utilization by the operation of the cycle was demonstrated. However, even during severe hypoxia (10% O_2, 85% N_2, 5% CO_2), the proportion of the total ATP produced during hypoxia utilized in the operation of the cycle was small (less than 3%). The influence of age, fasting(48h) and obesity on the operation of the TAG-NEFA cycle during normoxia and hypoxia was also studied. A five-fold difference in myocardial TAG concentration was found to be of little importance in determining the rate of the TAG-NEFA cycle. The rate of cycling was reduced in fasted rats. The role of endogenous catecholamines in the metabolic changes induced by hypoxia was investigated. Myocardial noradrenaline release could not be stimulated by oxygen deprivation. In contrast to isoprenaline-stimulated glycerol release, hypoxia-stimulated glycerol release could not be inhibited by β-adrenoceptor blocking agents. Furthermore, depletion of endogenous catecholamines by pretreament of rats with 6-hydroxydopamine caused only a 30% reduction in hypoxia stimulated glycerol release. In conclusion: 1) The operation of the TAG-NEFA cycle during hypoxia does not appear to cause a major drain on high energy phosphate supplies in the heart. 2) The rate of cycling is independent of myocardial TAG concentrations. 3) Glycerokinase activity can be demonstrated in the rat heart. 4) Glycerol release during hypoxia is mediated by non-adrenergic mechanisms and cannot be assumed to be an accurate reflection of myocardial lipolysis.

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Lindholm, Åsa Maria. "Metabolic Aspects in the Polycystic Ovary Syndrome." Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-120235.

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Lindholm, Åsa Maria. "Metabolic Aspects in the Polycystic Ovary Syndrome." Doctoral thesis, Uppsala universitet, Institutionen för kvinnors och barns hälsa, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-120235.

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Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders among women of childbearing age and is associated with a number of metabolic disturbances. It has been hypothesised these women carry an increased risk of developing cardiovascular diseases (CVD) with advancing age. The first aim of this thesis was to establish the prevalence of PCOS-related symptoms in Northern Sweden. The Northern part of the WHO MONICA project was used for this purpose. Based on self-reported menstrual disturbances and hirsutism together with biochemical analyses of free androgen index, the estimated prevalence of PCOS in Northern Sweden was 4.8%, which corresponded with previous prevalence studies. Disturbances in the fibrinolytic system are predictors of future cardiovascular events and measurements of plasminogen activator inhibitor 1 (PAI-1) activity and tissue plasminogen activator (tPA) mass concentration may be used to assess fibrinolytic activity in women with PCOS. From the findings, over-weight women with PCOS had impaired fibrinolysis, especially if they displayed objective biochemical markers of hyperandrogenism. Conversely, lean women with PCOS, displayed no signs of disturbed fibrinolysis. The adipose tissue is an active endocrine organ that produces and releases hormones, pro- and anti-inflammatory cytokines, and chemoattractant cytokines. Proinflammatory molecules produced by adipose tissue can be active participants in the development of insulin resistance and the increased risk of cardiovascular disease associated with obesity. The findings suggested being overweight, rather than the PCOS diagnosis per se, was the main explanatory variable for elevated adipose tissue inflammation in PCOS patients. Weight reduction is the primary target for intervention in overweight and obese women with PCOS. When this thesis was planned, no placebo-controlled trials on anti-obesity drugs in women with PCOS had been conducted. Sibutramine in combination with lifestyle intervention resulted in significant weight reduction in overweight women with PCOS. In addition to the weight loss, sibutramine appeared to have a beneficial effect on metabolic and cardiovascular risk factors.

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Bisi, Maria Cristina <1983&gt. "Bioengineering of exercise: biomechanical and metabolic aspects." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2543/.

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The field of research of this dissertation concerns the bioengineering of exercise, in particular the relationship between biomechanical and metabolic knowledge. This relationship can allow to evaluate exercise in many different circumstances: optimizing athlete performance, understanding and helping compensation in prosthetic patients and prescribing exercise with high caloric consumption and minimal joint loading to obese subjects. Furthermore, it can have technical application in fitness and rehabilitation machine design, predicting energy consumption and joint loads for the subjects who will use the machine. The aim of this dissertation was to further understand how mechanical work and metabolic energy cost are related during movement using interpretative models. Musculoskeletal models, when including muscle energy expenditure description, can be useful to address this issue, allowing to evaluate human movement in terms of both mechanical and metabolic energy expenditure. A whole body muscle-skeletal model that could describe both biomechanical and metabolic aspects during movement was identified in literature and then was applied and validated using an EMG-driven approach. The advantage of using EMG driven approach was to avoid the use of arbitrary defined optimization functions to solve the indeterminate problem of muscle activations. A sensitivity analysis was conducted in order to know how much changes in model parameters could affect model outputs: the results showed that changing parameters in between physiological ranges did not influence model outputs largely. In order to evaluate its predicting capacity, the musculoskeletal model was applied to experimental data: first the model was applied in a simple exercise (unilateral leg press exercise) and then in a more complete exercise (elliptical exercise). In these studies, energy consumption predicted by the model resulted to be close to energy consumption estimated by indirect calorimetry for different intensity levels at low frequencies of movement. The use of muscle skeletal models for predicting energy consumption resulted to be promising and the use of EMG driven approach permitted to avoid the introduction of optimization functions. Even though many aspects of this approach have still to be investigated and these results are preliminary, the conclusions of this dissertation suggest that musculoskeletal modelling can be a useful tool for addressing issues about efficiency of movement in healthy and pathologic subjects.
L’ambito di ricerca di questa tesi riguarda la bioingegneria dell’esercizio fisico, in particolare l’integrazione tra conoscenze biomeccaniche e metaboliche. La relazione tra questi due aspetti consentirebbe una valutazione completa dell’esercizio fisico che potrebbe aiutare la pratica clinica in diversi ambiti (ottimizzazione della performance di atleti, comprensione e compensazione del consumo energetico nei pazienti protesizzati, identificazione di esercizi ad alto consumo calorico e basso carico alle articolazioni per pazienti in sovrappeso). Inoltre, potrebbe avere applicazioni tecniche nel design di macchine per il fitness e per la riabilitazione. Lo scopo di questo lavoro era di approfondire la conoscenza riguardante la relazione tra lavoro meccanico e costo energetico metabolico durante il movimento, attraverso l’utilizzo di modelli interpretativi. Il problema è stato affrontato attraverso l’utilizzo di modelli muscolo scheletrici che includono oltre alla descrizione meccanica anche la descrizione della spesa energetica muscolare e che quindi permettono di valutare il movimento umano sia in termini meccanici che in termini di spesa energetica. E’ stato identificato in letteratura un modello muscolo scheletrico dell’intero corpo che potesse descrivere sia aspetti meccanici che metabolici; tale modello è stato applicato e validato utilizzando un approccio guidato da dati sperimentali di cinematica e elettromiografia (EMG-driven). Il vantaggio principale nell’utilizzo di un approccio EMG-driven è evitare l’introduzione di funzioni di ottimizzazione arbitrarie che servono per risolvere il problema indeterminato delle forze muscolari attorno alle articolazioni. E’ stata quindi condotta un’analisi di sensitività sul modello con lo scopo di conoscere quanto le variazioni nei parametri possono influire sulle uscite del modello stesso: i risultati hanno mostrato che variazioni dei parametri all’interno di range fisiologici non influenzano largamente le uscite del modello. Successivamente, il modello muscolo scheletrico è stato applicato ai dati sperimentali al fine di valutare la sua capacità predittiva: la valutazione è stata prima effettuata su un esercizio semplice (leg press unilaterale) e poi su uno più completo (esercizio ellittico). Le predizioni energetiche del modello sono risultate vicine ai dati di consumo energetici stimati tramite calorimetria indiretta nei casi studiati, in particolare alle basse velocità di esercizio e a diversi livelli di intensità. In conclusione, l’utilizzo di modelli muscolo scheletrici per predire il consumo energetico è risultato promettente e l’uso di un approccio EMG-driven ha permesso di evitare l’utilizzo di funzioni di ottimizzazione. Sebbene i risultati ottenuti siano preliminari e molti aspetti dell’approccio proposto debbano essere ulteriormente studiati, le conclusioni di questa tesi suggeriscono che la modellazione muscolo scheletrica può essere uno strumento utile per rispondere a domande riguardanti l’efficienza del movimento in soggetti sani o patologici.

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10

Guberović, Iva. "The metabolic aspects of macroH2A histone variants." Doctoral thesis, Universitat de Barcelona, 2021. http://hdl.handle.net/10803/673875.

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The histone variant macroH2A is the only structural chromatin component containing a macrodomain. In vertebrates, two genes and one event of alternative splicing give rise to three macroH2A proteins that differ in their macrodomains. As histone variants, macroH2A proteins contribute to the protein content of chromatin (Buschbeck & Hake, 2017). On the other hand, the capacity to bind ADP-ribose via its macrodomain is limited to the splice variant macroH2A1.1 (Kustatscher et al., 2005). As a consequence, macroH2A1.1, but not macroH2A1.2 or macroH2A2, binds auto-ADP-ribosylated PARP1 (Timinszky et al., 2009). Since the alternative splicing of the exon 5 affects the binding pocket of macroH2A1.2, as a consequence it cannot bind ADP-ribose (Kustatscher et al., 2005) and it remains an orphan protein. In the first study presented here, we investigated the evolution of the macrodomain-containing histone variant macroH2A1.1, an integral chromatin component that limits nuclear NAD+ consumption by inhibiting PARP1. We found that macroH2A originated in pre-metazoan protists. The crystal structure of the macroH2A macrodomain from the protist Capsaspora allowed us to identify highly conserved principles of ligand binding and pinpoint key residue substitutions, selected for during the evolution of the vertebrate stem lineage. Metabolic characterization of the Capsaspora life cycle indicated that the metabolic function of macroH2A was associated with non-proliferative stages. Taken together, we provide insight into the evolution of a chromatin element involved in compartmental NAD regulation, relevant for understanding of its metabolism and potential therapeutic applications. In the second study, we described the structurally relevant elements for ligand binding by the orphan macroH2A isoform, macroH2A1.2. Furthermore, using targeted and untargeted approaches on the verge of in silico, in vitro and in cellulo approaches, we detected phospholipids as the first putative physiological ligands of macroH2A1.2. We further observed a behavioral phenotype in macroH2A1.2 knock-out mice and report for the first time the upregulation of macroH2A1.2 expression in the differentiated cells, more specifically in differentiated neurons. We postulate that macroH2A1.2 might have a binding-pocket related role in the regulation of behavior, similarly to what was observed for PPARα in hypothalamus, whereby it regulates animal behavior depending on the binding of its phospholipid ligands (Chakravarthy et al., 2007; Roy et al., 2016).

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11

Shirazi, Farshad 1963. "Metabolic aspects of neonatal rat cardiomyocyte hypertrophy." Diss., The University of Arizona, 1997. http://hdl.handle.net/10150/282447.

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The consensus view is that cardiac hypertrophy is an adaptive response to increased work caused by a variety of stimuli. While hypertrophy can be defined as an increase in cell mass without an increase in cell number, not all increases are equivalent in type and amount of protein accumulated. Our goal in this study was to identify the common steps in the process of cardiac hypertrophy. Our working hypothesis was that in all forms of cardiac hypertrophy glucose utilization increases and that the percentage of energy derived from fatty-acid oxidation decreases. The first part of this study entailed the development and characterization of a neonatal rat heart cell model. The model had to provide uniform culture conditions for rapid development of hypertrophy by agents acting at different sites in the cardiomyocytes. The second part of this study was composed of an assessment of hypertrophy caused by four pharmacologically distinct agents: norepinephrine, angiotensin-II, endothelin-I and tetradecylglycidic acid. In this part we compared the quantity of protein accumulation and quality of hypertrophy cause by each agent. This task was accomplished by examining the effect of each agent on selected mRNA messages and alteration in DNA content of cardiomyocytes. Here we also examined the effect of protein kinase-C, endothelin-I and angiotensin-II inhibitors on hypertrophy caused by each agent. In the final part of this study, metabolic alteration in hypertrophy caused by each agent was assessed for a potential common pathway to hypertrophy. As part of this analysis, we examined changes in glucose and palmitate oxidation, glucose uptake and role of pentose pathway in hypertrophy resulting from treatment of cardiomyocyte by each agent.

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12

Jenkins, Timothy Mark. "Molecular and metabolic aspects of succinate thiokinase." Thesis, University of Bath, 1988. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383299.

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13

Ghosh, Nandini. "MOLECULAR ASPECTS OF LIPID METABOLISM IN NUTRITIONAL INTERVENTIONS: FOCUS ON DEGENERATIVE METABOLIC CONDITIONS." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu156346872132189.

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Duijnhoven, Elly M. van. "Metabolic and pharmacokinetic aspects of tacrolimus in renal transplantation." Maastricht : Maastricht : Universitaire Pers Maastricht ; University Library, Maastricht University [Host], 2002. http://arno.unimaas.nl/show.cgi?fid=7135.

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15

Cervellati, Claudia <1983&gt. "Metabolic and molecular aspects of cyanogenesis in apricot seed." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amsdottorato.unibo.it/3843/.

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Bosagh, Zadeh Ali Reza. "Some aspects of the metabolic response to surgical trauma." Thesis, King's College London (University of London), 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299907.

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17

Audet, Diane. "Metabolic cost of aerobic dance circuit training." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=56816.

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This study was undertaken to characterize the oxygen consumption and heart rate responses of subjects during laboratory simulated aerobic dance circuit training sessions. Sixteen female subjects performed six randomly assigned 30-minute aerobic dance circuit training protocols. Oxygen consumption and heart rate responses were monitored in response to changes in three independent variables which were: interval duration, leg involvement and fitness level. Results revealed that the different interval durations generated significantly different oxygen costs. Also, it was found that in relative terms (% of max VO$ sb2$), the low fitness group (max VO$ sb2 $ 45 ml/kg.min). Furthermore, it was found that the involvement of deep knee bends during the resistance training segment of the circuit significantly increased the oxygen cost when the resistance training segments were compared. Finally, the results showed that exercise intensity was overestimated when using percentage of max HR.

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Tan, Bee Kang. "Adipokines and the Metabolic Aspects of the Polycystic Ovary Syndrome." Thesis, University of Warwick, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.490677.

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Polycystic Ovary Syndrome (PCOS) is the most common endocrine disorder amongst women of reproductive age associated with a number of adverse metabolic sequealae. These women have an increased risk of insulin resistance and hyperinsulinemia, an increased risk of glucose intolerance and type 2 diabetes mellitus, dyslipidemia, subclinical atherosclerosis and vascular dysfunction, independent of BMI. With the epidemic of obesity, the PCOS phenotype is becoming ever more so prevalent and represents a clear and present health issue that needs to be addressed urgently. The studies describe for the first time the expression of visfatin and Retinol-Binding Protein 4 (RBP4) as well as adiponectin receptors, in corresponding sc and om human adipose tissues at both mRNA and protein levels. Also, it was shown that there was significant upregulation of visfatin and RBP4 as well as adiponectin receptors gene expression and protein in both these adipose tissue depots in overweight women with PCOS, including significantly higher circulatin visfatin and RBP4 levels, compared with matched controls. Furthermore, in isolated sc adipocytes, visfatin and RBP4 mRNA as well as adiponectin receptor(s) expression was significantly higher in age, BMI and WHR matched overweight PCOS women. Leptin was found to regulate om adipose tissue visfatin protein production and secretion, exhibiting a 'biphasic' response with a peak at leptin 10-9 M; a dose which is of physiological relevance in both mice and humans; returning to baseline with higher doses of leptin. This was true even in experiments conducted with C57BLIKs db/db mice, which lacked the membrane bound long leptin receptor (OB-Rb); thus highlighting the possible role of the membrane bound short leptin receptor (OBRa) in leptin induced visfatin protein production. Also, the apparent diminished response to higher doses of leptin with respect to visfatin production may be partly explained by the concurrent significant increase in the secretion of the soluble leptin receptor (SLR) at higher doses ofleptin. Binding ofleptin with SLR decreases the bioavailability of leptin to membrane bound leptin receptors and as a consequence, attenuates leptin's biological actions. Finally, when omental adipose tissues were subjected to leptin treatment in the presence of inhibitors of MAPK and PI3K, there was a significant decrease in leptin induced visfatin protein production and secretion. The MAPK and PI3K signalling pathways are known to functionally signal through both the short (OB-Ra) as well as the long (OB-Rb) leptin receptors. Leptin and visfatin may therefore playa coordinated role in various bodily functions, for example adipogenesis. Furthermore, the studies provide novel evidence that testosterone and 17~-estradiol increase both AdipoRl and AdipoR2 mRNA and protein levels; also, that 17~-estradiol significantly increases RBP4 secretion and up-regulates RBP4 mRNA expression and protein levels in human sc and om adipose tissue explants. Finally, HEK-293 cells were found to be suitable to further study and clarify the signalling pathways of both AdipoRl and AdipoR2. The temporal differences observed with respect to the activation ofAMPK between globular adiponectin and full length adiponectin forms the basis of further studies looking into the regulation of glucose and lipid metabolism, the molecular causes of diabetes and atherosclerosis, and the development of anti-diabetic and anti-atherosclerotic drugs.

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Gemert, Wilhelmus Gerardus van. "Surgical treatment of morbid obesity technical, psychosocial and metabolic aspects /." [Maastricht : Maastricht : Universiteit Maastricht] ; University Library, Maastricht University [Host], 1999. http://arno.unimaas.nl/show.cgi?fid=8566.

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Taveroff, Arlene. "Metabolic derangements following bone marrow transplantation : an integrated analysis." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74259.

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Bone marrow transplantation (BMT) involves the use of maximal doses of chemotherapy and total body irradiation. As a result, even well-nourished patients exhibit negative nitrogen balance and hypoproteinemia in the post-transplant period, despite a high energy and protein intake from Total Parenteral Nutrition (TPN). The purpose of this research was to investigate the impact of cytotoxic therapy, with a view toward explaining and improving the response to nutritional support. Stool, urine and serum biochemistry were studied prospectively in 10 BMT patients. Analysis of stool revealed increased sodium and decreased potassium. Examination of serum electrolytes indicated hyponatremia and hyperkalemia. A significant decrease in nitrogen balance, serum albumin and net protein utilization immediately followed the disturbances in serum electrolytes; improvement began as serum sodium and potassium returned to normal. Thus, electrolyte imbalance may have reduced the capacity of cells to utilize nitrogen. Lowering the volume of TPN dramatically decreased serum electrolyte aberrations and improved nitrogen utilization.

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Hesselink, Matthijs Karel Christiaan. "Structural, functional and metabolic aspects of shortening and lengthening muscle contractions." Maastricht : Maastricht : Universiteit Maastricht ; University Library, Maastricht University [Host], 1998. http://arno.unimaas.nl/show.cgi?fid=6030.

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22

Böttiger, Ylva. "Metabolic drug interactions in man : methodological aspects on in vivo studies /." Stockholm, 2000. http://diss.kib.ki.se/2000/91-628-4207-2/.

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23

Bruce, N. C. "Enzymic and metabolic aspects of aromatic ring degradation in nocardioform actinomycetes." Thesis, University of Kent, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376346.

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24

Bishop, Stephen Christopher. "Genetic and metabolic aspects of growth and its components in mice." Thesis, University of Edinburgh, 1985. http://hdl.handle.net/1842/10817.

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25

Ainslie, Philip N. "The prolonged exercise of hill walking : physiological, metabolic and ergonomic aspects." Thesis, Liverpool John Moores University, 2002. http://researchonline.ljmu.ac.uk/4995/.

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26

Westhoff, Philipp [Verfasser]. "Metabolic aspects of host pathogen interactions revealed by metabolomics / Philipp Westhoff." Greifswald : Universitätsbibliothek Greifswald, 2016. http://d-nb.info/1112473602/34.

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27

Khoo, Kong Kheong. "The influence of metabolic phenotypes upon the development of colorectal neoplasia /." Title page, table of contents and conclusions only, 1995. http://web4.library.adelaide.edu.au/theses/09MD/09mdk45.pdf.

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28

Flynn, Michael Gerald. "Fat storage in athletes : the metabolic and hormonal responses to swimming and running exercise." Virtual Press, 1987. http://liblink.bsu.edu/uhtbin/catkey/516210.

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Despite similar rates of energy expenditure during training, competitive swimmers have been shown to store significantly greater amounts of body fat than competitive runners. In an attempt to explain these discrepancies, male collegiate swimmers (n=8) and runners (n=8) were monitored during 45 min of swimming and running, respectively (75% V02 max), and during two hours of recovery. In addition, a group of male competitive triathletes (n=6) were similarly monitored during and after both swimming and running exercise.Blood samples were obtained after 15 min rest prior to exercise and at 0, 15, 30, 60 and 120 min of recovery and were analyzed for glucose, lactate, glycerol, free fatty acids, insulin, glucagons, norepinephrine (NE) and epinephrine (E). Respiratory gases were collected at 15 min intervals during exercise and at 15, 30, 45, 60, 90 and 120 min of recovery. Heart rate and mean body temperature were recorded at 10 min intervals throughout recovery. There were no differences in post-exercise oxygen consumption or heart rate while the RER suggested increased fat oxidation after exercise for the swimmers and the swimming triathletes. The mean body temperature and mean skin temperatures were significantly lower throughout 120 min of recovery for the swimmers compared to the runners. The triathletes demonstrated a similar tendency but these differences were not significant. The serum glucose levels were significantly greater (P<0.05) immediately post-exercise for the runners compared to the swimmers (6.71 +0.29 and 4.97 +0.19 mmol•1-1, respectively). Blood glucose values were also significantly greater immediately post-run for the triathletes (6.40 +0.26 and 4.87 ±0.18 mmol-l-1 for running and swimming, respectively). Blood glucose values remained elevated for runners and the running triathletes up to 30 min of recovery. Free fatty acids were similar after the run and the swim, but glycerols were increased immediately after running in the runners (P<0.05) and the triathletes (P<0.05). Differences in blood glucose levels or fat release were not explained by differences in NE, E or cortisol. The glucagon-to-insulin (G:I) ratio was significantly increased after exercise in the swimmers and the swimming triathletes. This, combined with a reduced RER after the swimming trials, suggests that the reduced glucose levels were due to reduced hepatic glycogen stores. The results of this study suggest that there were differences in substrate utilization during running and swimming exercise of the same intensity. These differences were not explained by NE, E or cortisol; however, the increased G:T ratio suggests increased carbohydrate use during exercise in the swimmers. Finally, body fat differences between runners and swimmers were not explained by differences in post-exercise energy expenditure or fat oxidation.

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29

Ferguson, Matthew J. "The metabolic and muscular adaptations to cycle training with Powercranks." Virtual Press, 2007. http://liblink.bsu.edu/uhtbin/catkey/1371690.

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PowercranksTM are a device that enables the user to cycle with each leg acting independently of the other. This type of cycling forces the rider to actively pull up with the hip and knee flexors throughout the recovery phase of the pedaling cycle. While the metabolic benefits of training with PowercranksTM are known, no research has investigated what, if any, strength benefits result from training. The purpose of this study was to examine how strength, submaximal oxygen consumption, hear rate, gross efficiency, and muscle activation were affected by 6 weeks of PowercranksTM training, compared to a traditional cycling training. A total of 1 1 recreationally trained adult subjects (5 males, 6 females) were randomly placed into either the PowercranksTM group (PC) or regular cranks (RC) group. Subjects trained 3 days per week following a progressive interval protocol for 6 weeks. Prior to and following training, subjects were measured for peak isokinetic knee and hip flexion/extension strength, timing of muscular contractions, and submaximal VO2, heart rate, and gross efficiency. A MANOVA for strength values pre-post were not significant. However, large effect sizes implied that there were increases in knee and hip flexion for the PC group (d =1.00,1.63, respectively). Heart rate was found to be significant at all 4 time points (p = 0.001, 0.011, 0.001, 0.000 for time points 1-4, respectively). MANOVAs for VO2 and GE did not yield significant results. Muscular timing was also unchanged as a result of training. While the PowercranksTM did not have an effect on VO2 and GE in untrained subjects, HR decreased, suggesting an aerobic benefit. The possible strength benefits in untrained subjects resulting from PowercrankTM training could prove beneficial for individuals looking to recover from injury.
School of Physical Education, Sport, and Exercise Science

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30

Rautio, K. (Katriina). "Effects of insulin-lowering drugs in PCOS: endocrine, metabolic and inflammatory aspects." Doctoral thesis, University of Oulu, 2006. http://urn.fi/urn:isbn:951428268X.

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Abstract Most women with polycystic ovary syndrome (PCOS) exhibit features of metabolic syndrome, including insulin resistance, abdominal obesity, dyslipidaemia, glucose intolerance and low-grade chronic inflammation, reflected in elevated levels of serum C-reactive protein (CRP), placing these women at increased risk of cardiovascular disease and type 2 diabetes (type 2 DM). The aim of this study was to investigate the effects of two well-known insulin-lowering drugs used in the treatment of type 2 DM, metformin and rosiglitazone, on traditional cardiovascular risk factors and inflammation in women with PCOS. In addition, the impact of rosiglitazone was evaluated as regards clinical, endocrine and metabolic aspects of PCOS. Six-months of metformin treatment in women with PCOS had beneficial effects on levels of CRP, lipid profile and blood pressure, expressed as increased levels of high-density lipoprotein cholesterol (HDL-C), and decreased levels of triglycerides (TGs), decreased ratio of total cholesterol/HDL-C, decreased levels of CRP, and decreased systolic and diastolic blood pressures. Four-month treatment with rosiglitazone in a randomised, double-blind, placebo-controlled study in overweight women with PCOS resulted in significant improvements in menstrual cyclicity, hyperandrogenism, insulin resistance and hyperinsulinaemia. In addition, rosiglitazone decreased levels of markers of low-grade inflammation, CRP and white blood cell (WBC) count, and the liver function marker alanine aminotransferase (ALAT), while having neutral effects on levels of lipids, and blood pressure. In conclusion, metformin treatment, in accordance with the known beneficial metabolic effects of this drug, could be useful in the prevention of cardiovascular complications in women with PCOS. Rosiglitazone represents an alternative treatment for overweight anovulatory women with PCOS. It could be useful in the prevention of type 2 DM in overweight women with PCOS and for those suffering from possible side-effects related to metformin treatment. In addition, alleviation of inflammation and improvement of liver function during rosiglitazone treatment may indicate decreased future risks of cardiovascular diseases and non-alcoholic fatty liver disease (NAFLD).

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31

Tappi, Silvia <1980&gt. "Qualitative, Metabolic and Nutritional Aspects of Traditional and Innovative Minimally Processed Fruit." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amsdottorato.unibo.it/7633/.

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Minimally processed fruit (MPF) are products that have to maintain their quality similar to those of fresh ones. Being metabolic active tissues, they show physical and physiological response to minimal processing (wounding), that negatively influence their shelf-life. In the last decades, novel non-thermal processing methods have attracted the interest of food scientists, industries and consumers as technologies useful for shelf-life extension or increasing product functionality, with a minimal impact on the nutritional and sensory properties of foods. The main aim of this PhD thesis was to investigate qualitative, metabolic and nutritional aspects of different MPF, submitted to traditional and innovative non-thermal processes. This issue was addressed considering the product as a dynamic system, both in terms of endogenous physiological activity and porous matrix interacting with the surrounding ambient (during processing and storage), through the application of multi-analytical approach. The most consistent results related to the applied non-thermal techniques confirmed their different potentiality in the optic of processing and product innovation, but the need of their modulation in relation to the different raw material susceptibility to degradation and final product target. Cold plasma treatment effects on fresh-cut fruit, characterized by different kind of stability criticisms, resulted mainly bound to the inactivation of degradative enzymes and microbial cells, without evidencing functional modifications in the final products. The study of osmotic dehydration and vacuum impregnation highlighted as these techniques can be successfully applied for cold formulation/enrichment of MPF, but also the necessity to carefully account for the metabolic and structural modifications induced by the processing on the vegetable tissues. An induction of metabolic stress response was also evidenced as a consequence of pulsed electric fields treatment related to electric field strength. Below the threshold limit of irreversible damages to cell membranes, the treatment promoted only slight and reversible modifications of the metabolic profiles.

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32

Pivovarova, Olga [Verfasser]. "Cardiovascular, inflammatory and circadian aspects of metabolic regulation in humans / Olga Pivovarova." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2017. http://d-nb.info/1149050721/34.

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33

Dengel, Donald R. "Metabolic determinants of success during triathlon competition." Virtual Press, 1986. http://liblink.bsu.edu/uhtbin/catkey/452141.

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Eleven male triathletes were studied to determine the relationships between selected metabolic measurements and triathlon performance. Measurements were made for oxygen consumption (V02), pulmonary ventilation (Ve) and heart rate (HR) during submaximal and maximal 400-yd freestyle swimming (FS), cycle ergometry (CE) and treadmill running (TR). Submaximal workloads were 1 m/sec for swimming, 200 watts for cycling and 7.5 mph for running. The mean (1/min) was significantly (P<0.05) lower during 1/min) than CE (4.68 1/sin) or TR (4.81 1/min). cycling and running performance times during the (1.2 mile swim, 56 mile cycle, 13.1 mile run) were to have a low relationship to V0z max (ml/kg/min) -0.32 and -0.55, respectively. The V0z max when expressed as 1/min was found to significantly (P<0.05) related to cycling time (r=-0.70). However, at a selected workload the %VO2 max was found to be highly related to swimming (0.91), cycling (0.78) and running (0.86) performance times. Maximal HR (bts/min) was also observed to be significantly (P<0.05) lower during FS (163) than CE (176) or TR (183). Running and cycling times in the triathlon were highly correlated (P<0.05) to overall triathlon performance times, 0.97 and 0.81, respectively, whereas swimming was found to be less a contributor to the athlete's final time, r=0.30. This study suggests that economy of effort is of greater importance to a triathlete's performance than their maximal oxygen uptake.

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34

Patel, Kishor Kantilal. "Physiological aspects of weight loss in obesity." Thesis, University of Nottingham, 2011. http://eprints.nottingham.ac.uk/12052/.

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Obesity continues to be a major cause of morbidity and mortality and worldwide prevalence rates continue to rise. The cornerstone for treating obesity remains diet and lifestyle, with the ultimate goal being normalising those parameters that are associated with ill health, for example hyperinsulinaemia and insulin resistance. Because obesity predominantly develops due to a mismatch between energy intake and utilisation, this thesis looked at the effects of dietary interventions upon Resting Energy Expenditure (REE) and substrate oxidation. In addition, the impact of popular dietary interventions upon body composition and insulin resistance was examined. When phenotypic characteristics were investigated before and after weight loss by using hypocaloric diets, which differed in fat and carbohydrate content, Fat-Free Mass (FFM) and Fat Mass (FM), were strong predictors of REE before and after the intervention and weight loss rather than the specific dietary intervention, significantly predicted post intervention REE. Fasting fat oxidation was found to be lower in obese subjects and they had a lower postprandial response to a high fat challenge. This implied that a diet high in fat is more likely to promote a positive energy balance an ultimate weight gain. The final study compared 4 popular dietary interventions. Each was equally effective at achieving clinically significant weight loss and improvements in insulin sensitivity. Although none was significantly more superior, there was a trend supporting three of the diets (Atkins’, Weight Watchers and Rosemary Conley) above the other (Slim-Fast) and it was the pattern of weight loss, i.e. mainly loss of FM, which proved beneficial with regards to improving insulin sensitivity. In summary, this thesis confirms that REE is mainly predicted by FFM and FM and that there is diminished fat oxidation on obese subjects. What this thesis also adds to previous research that it if a specific diet can improve the pattern of weight loss, this can be clinically beneficial.

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35

Butler, Ross Norman. "Aspects of the relationship between metabolic and proliferative activity in the large bowel /." Title page, contents and abstract only, 1990. http://web4.library.adelaide.edu.au/theses/09PH/09phb986.pdf.

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36

Trichia, Eirini. "Dairy products and cardio-metabolic health : aspects from nutritional, molecular and genetic epidemiology." Thesis, University of Cambridge, 2019. https://www.repository.cam.ac.uk/handle/1810/290034.

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There is accumulating evidence on differences in the link between types of dairy products and cardio-metabolic health, but inconsistent findings limit the field. In my PhD project, I undertook an epidemiological investigation comprising inter-related but distinct themes evaluating aspects of nutritional, molecular and genetic epidemiology to advance scientific understanding. I undertook research to describe dairy consumption patterns over time by evaluating nationally-representative data of the United Kingdom National Diet and Nutrition Survey. I observed significant time trends for specific dairy types and groups, which were different among different groups of people e.g. adults younger than 65 years or elderly people. Using data from the large Fenland (n~12,000) and EPIC Norfolk (n~25,000) studies, I investigated associations of total and types of dairy consumption with markers of metabolic risk and adiposity as potential pathways to cardio-metabolic disease. The analyses showed differential associations of dairy types and groups mainly with markers of adiposity and lipidaemia. I explored the potential of objective markers to assess dairy consumption, by examining metabolomics profiles and blood fatty acids to identify a set of biomarkers predicting dairy consumption and prospective associations of the identified biomarkers with type 2 diabetes risk. I was able to develop and validate metabolite scores reflecting consumption of some dairy products and observed inverse associations between some of these scores and type 2 diabetes incidence. I analysed genetic determinants of dairy consumption, using a genome-wide association study in the UK Biobank (n~500,000) and identified single nucleotide polymorphisms predicting milk, cheese and total dairy consumption. Overall, this PhD work contributed towards (1) a more precise description of dairy consumption patterns in the UK, (2) hypothesis formulation for potential biological pathways linking to cardio-metabolic disease, (3) discovery of metabolite scores as potential dairy biomarkers and (4) hypothesis formulation for potential genetic predictors of dairy consumption.

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37

Socha, Catherine. "Study of the metabolic aspects of resilience to intestinal infections in Drosophila melanogaster." Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAJ106.

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Lors d’une infection microbienne, la défense de l’hôte comprend deux facettes complémentaires. Premièrement, le système immunitaire cible les pathogènes dans le but de les éliminer, une attaque correspondant à la résistance. Dans un second temps, l’organisme doit réparer les dégâts causés par le pathogène ou par la réponse immunitaire de l’hôte, un mécanisme appelé résilience. J’ai étudié les effets d’une infection intestinale par la bactérie Serratia marcescens chez la drosophile. Nous avons mis en évidence un processus de purge dans l’intestin, lors duquel les enterocytes -les cellules principales de l’intestin- se vident partiellement de leur contenu. L’épithélium intestinal devient alors très fin mais se régénère rapidement, protégeant ainsi la mouche des effets délétères de l’infection. J’ai identifié un transporteur d’acides aminés, CG1139, qui est nécessaire à la régénération de l’intestin. CG1139 est requis pour la mobilisation de certaines réserves métaboliques de la drosophile et pour le transport rétrograde de ces dernières vers l’intestin
Upon microbial infections, host defenses comprise two complementary facets. First, immune effectors target and kill the invading pathogen, an attack referred to as resistance. Second, the infected host must repair the damages inflicted by microbes or by the immune response itself, a mechanism called resilience. I have studied the effects of an intestinal infection with the bacterium Serratia marcescens in Drosophila. We have discovered a purge mechanism in the intestine, where enterocytes -the main cell type in the gut- extrude some of their internal contents. The intestinal epithelium thus becomes very thin but rapidly recovers its shape, thereby protecting the fly against the deleterious effects of infection. I have identified an amino acid transporter, CG1139, which is required for the intestinal recovery. CG1139 is necessary to mobilize the fly’s internal metabolic reserves and to transport some these metabolic stores back to the gut, in a retrograde manner

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38

Howe, Cheryl A. "The effects of warm-up intensity on anaerobic performance and metabolic recovery in male children." Virtual Press, 1994. http://liblink.bsu.edu/uhtbin/catkey/917031.

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The purpose of this study was to examine the effects of warm-up intensity on anaerobic performance and recovery in children. Six male children (11.0 ± 0.6 yr) performed an IAT following a mild (85% of VAT), intense (115% of VAT), or no warm-up protocol. VAT was determined during a previously performed GXT. A catheter allowed for multiple blood samples drawn thoughout each trial. Performance indices, PP, MP, TW, and FI%, were not significantly different across trials. Blood analysis revealed significant interactions for recovery [LA] and [HC03-], although no significant interaction for pH values. There was also a significant interaction for V02 recovery pattern. The ALA (5.2 vs. 7.1 mmol•1-1, respectively) and AHC03- (6.1 vs. 8.4 mmol-l-1, respectively) were significantly lower for the AVAT trial compared to NWU trial. These data indicate that the AVAT warm-up resulted in less acid-base balance disturbance suggesting greater dependence on aerobic metabolism during the IAT.
School of Physical Education

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39

Ramabhai, Leena I. "The effect of load carriage on selected metabolic and perceptual responses of military personnel." Thesis, Rhodes University, 2000. http://hdl.handle.net/10962/d1005189.

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Taking a multi-disciplinary, integrated approach, the present study sought to examine selected physiological and psycho-physical parameters related to load carriage involving a 12 km march under military conditions. Military constraints hampered, but did not entirely inhibit the secondary aim of the study which concerned the effectiveness of relativising loads in order to normalise responses for all soldiers, irrespective of morphological diversity. Forty three subjects were measured in six groups using a test-retest experimental protocol. They were involved in a rest-broken 12 km march at 4 km.h⁻¹ under 40.5 kg absolute total load and under a relative load of 37% of body mass. Heart rates, ratings of perceived exertion (RPE) as well as area and intensity of discomfort were monitored for all subjects. Ten subjects were measured more extensively with regard to physiology using the Metamax, a portable ergospirometry system that provides all the data needed for a complete functional analysis of lung, heart, circulation and metabolic activity. Physiological responses (fc; fb; V̇T; V̇E; V̇O₂; EE; V̇CO₂; R; T°) indicated subjects were not severely physically taxed and that the loads imposed constituted a sub-maximal demand. Moreover, there appeared to be a limited cumulative effect over the 3.5 h. Data from the first and third hours were similar, while the significantly higher responses in the second hour reflected the challenge of the undulating terrain encountered during this section of the march. All responses during the Relative load conditions mirrored those of the Absolute load condition but, because the demands were less, the trends occurred at a reduced level. Furthermore, the reduction in inter-individual variability indicates that relativised load carriage tends to stress the soldiers in a more uniform manner. All "local" RPE responses were higher than "central" ratings, suggesting soldiers were in good cardiovascular condition and experienced marginally more strain in the lower limbs. There was increased perceived strain corresponding to the increase in gradient, with little cumulative effect over the three hours. The shoulders and feet were the two regions in which most discomfort was experienced; the shoulders being the worst area in the first hour and the feet being rated the worst after the third hour of marching. This study clearly demonstrates the probability of a significant improvement in mean combat-readiness following loaded marching by showing that, if loads are set at levels commensurate with individual capabilities to carry them without undue strain, unnecessary physical demands experienced by smaller, more gracile soldiers are reduced.

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40

Goh, Kah Lay. "Skin microvascular function in type 2 diabetes and related aspects of the metabolic syndrome." Thesis, University of Leicester, 2001. http://hdl.handle.net/2381/29384.

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Microangiopathy is a major cause of morbidity and mortality in type 2 diabetes. This thesis investigates the factors that may influence the microcirculation in type 2 diabetes and related aspects of the metabolic syndrome, using techniques that interrogate the skin microvascular function. The first study explores the concept of intrinsic microvascular dysfunction. Low birth weight has been linked with the increased risk of developing type 2 diabetes and cardiovascular disease in adult life. Impaired maximum hyperaemic response to local heating was demonstrated in the lowest-quartile birth weight infants compared to the highest-quartile birth weight group. Skin endothelium-dependent vasodilatory function and capillary density were not different between the two groups. In a separate study involving prepubertal and postpubertal subjects, both skin maximum hyperaemic response and postural vasoconstriction response were not related to birth weight. It is possible that extrinsic factors or perhaps the rapid phase of growth and sexual maturation during childhood may have modified the relationship between birth weight and microvascular function. There has been much interest in the role of postprandial dyslipidaemia in macrovascular disease but its effect on the microcirculation is not known. In a group of healthy volunteers, skin microvascular response was not significantly attenuated after a high-fat meal. However, the change in vasodilatory response correlated strongly with the postprandial rise in triglycerides. In a corresponding study in type 2 diabetic subjects, skin microvascular function was significantly reduced after a high-fat meal. Thus it would appear that both intrinsic and extrinsic influences are important factors in determining skin microvascular function and the interplay between the elements that are present at birth and subsequent exposures is one of the essential challenges for future research.

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41

Nijhuis, Jeroen. "Bariatric surgery and its effect on the metabolic and inflammatory aspects of morbid obesity." Maastricht : Maastricht : Universitaire Pers Maastricht ; University Library, Universiteit Maastricht [host], 2008. http://arno.unimaas.nl/show.cgi?fid=11592.

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42

Cole, Kevin J. "The effects of caffeine sensitivity on metabolic substrate use and performance." Virtual Press, 1994. http://liblink.bsu.edu/uhtbin/catkey/902503.

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This study was designed to determine if highly caffeine sensitive (HS) and less caffeine sensitive (LS) individuals differ in metabolic substrate use and endurance performance following caffeine ingestion. Twenty subjects were placed into HS and LS groups based on a series of 6 isokinetic cycle ergometer rides in which perceived exertion was held constant and work output was measured. Subjects who performed significantly more work following caffeine ingestion were classified as HS while those who did not were classified as LS. Seven subjects were selected from each of these groups to perform the experimental trials. These trials were conducted 60 min after ingestion of 6 mg-kg-1 caffeine or a placebo and consisted of a 30 min ride at70% VO2max followed by a 60 min isokinetic performance ride. The HS group achieved a higher accumulated workload over the last 30 min of the ride following caffeine ingestion compared to the placebo condition. No increase in work output was observed in the LS group following caffeine ingestion. There were no significant differences between treatments in either the HS or LS group in amount of muscle glycogen utilized during the first 30 min of the ride. During the caffeine trials serum glucose was elevated at 20, 30, and 50 min, free fatty acid concentration was elevated at the zero time point, and glycerol concentration was elevated at 60 and 90 min compared to the placebo trials. However, there were no differences between the HS and LS groups in these parameters. These data suggest that the ergogenic effects of caffeine in some individuals are not due to an alteration in substrate utilization, but may be related to an alteration in neural perception of effort.
School of Physical Education

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43

Bradbury, James. "Computational hypothesis generation with genome-side metabolic reconstructions : in-silico prediction of metabolic changes in the freshwater model organism Daphnia to environmental stressors." Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8437/.

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Computational toxicology is an emerging, multidisciplinary field that uses in-silico modelling techniques to predict and understand how biological organisms interact with pollutants and environmental stressors. Genome-wide metabolic reconstruction (GWMR) is an in-silico modelling technique that aims to represent the metabolic capabilities of an organism. Daphnia is an emerging model species for environmental omics whose underlying biology is still being uncovered. Creating a metabolic reconstruction of Daphnia and applying it in an environmental computational toxicology setting has the potential to aid in understanding its interaction with environmental stressors. Here, the fist GWMR of D. magna is presented, which is built using METRONOME, a newly developed tool for automated GWMR of new genome sequences. Active module identification allows for omics data sets to be integrated into in-silico models and uses optimisation algorithms to find hot-spots within networks that represent areas that are significantly impacted based on a toxicogenomic transcriptomics dataset. Here, a method that uses the active modules approach in a predictive capacity for computational hypothesis generation is introduced to predict unknown metabolic responses to environmentally relevant human-induced stressors. A computational workflow is presented that takes a new genome sequence, builds a GWMR and integrates gene expression data to make predictions of metabolic effects. The aim is to introduce an element of hypothesis generation into the untargeted metabolomics experimental workflow. A study to validate this approach using D. magna as the target organism is presented, which uses untargeted Liquid-Chromatography Mass Spectrometry (LC-MS) to make metabolomics measurements. A software tool MUSCLE is presented that uses multi-objective closed-loop evolutionary optimisation to automatically develop LC-MS instrument methods and is used here to develop the analytical method.

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44

Laberge, MacDonald Tammy. "Molecular Aspects of Nitrogen Metabolism in Fishes." Scholarly Repository, 2009. http://scholarlyrepository.miami.edu/oa_dissertations/668.

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Molecular aspects of nitrogen metabolism in vertebrates is an interesting area of physiology and evolution to explore due to the different ways in which animals excrete nitrogenous waste as they transition from an aquatic to a terrestrial lifestyle. Two main products of nitrogen metabolism in fishes are ammonia and urea. Ammonia is produced during protein catabolism and build up of ammonia is toxic. Some aquatic vertebrates convert ammonia into a less toxic compound urea via de novo synthesis through the ornithine-urea cycle (O-UC). Five enzymes are involved in the O-UC: carbamoyl phosphate synthetase (CPS), ornithine carbamoyl transferase (OCT), argininosuccinate synthetase (ASS), argininosuccinate lyase (ASL), and arginase (ARG). An accessory enzyme, glutamine synthetase (GS) also participates in the "fish-type" O-UC. Teleosts excrete ammonia passively over their gills into the aquatic environment. The teleost, Opsanus beta, has been shown to increase urea production after 48 hours of crowding. This thesis explored how crowding stress affected nitrogen metabolite levels of ammonia and urea and O-UC gene expression and enzyme activity in O. beta. Lungfishes while in an aquatic environment avoid ammonia toxicity by releasing excess ammonia across their gills, but when stranded on land they produce urea through the O-UC. Urea production via the O-UC has a metabolic cost of at least four ATP molecules. This thesis explored the response of a lungfish, Protopterus annectens, to six days of aerial exposure and re-immersion conditions by measuring concentrations of O-UC mRNA expression and enzyme activity and nitrogen metabolites ammonia and urea. CPS acts as the entry point to the O-UC and based on enzymatic studies, most aquatic vertebrates utilize one isoform of this enzyme (CPSIII) while terrestrial vertebrates utilize a different isoform of this enzyme (CPSI). Lungfishes are a particularly interesting group of air-breathing fishes, not only because of their link to the origins of tetrapods, but also because CPS I may have originated within this group. Both CPS III and CPS I have been enzymatically described within this group. This thesis uses phylogenetics to investigate how CPS nucleotide sequences in lungfishes evolved compared to other vertebrates.

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45

Zhang, Song. "Peripheral and central pathways linking metabolic status and reproduction in male sheep." University of Western Australia. School of Animal Biology, 2005. http://theses.library.uwa.edu.au/adt-WU2005.0037.

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[Truncated abstract] Reproductive activity is affected by external factors such as photoperiod, social cues, stress and nutrition, all of which can alter the pulsatile activity of the GnRH neurons, which is the major neuroendocrine system used by the brain to control gonadal function. In the male Merino sheep, nutrition is one of the most powerful factors that affect pulsatile LH secretion, used commonly to bioassay GnRH neuronal activity. More accurately, the reproductive system responds to “metabolic status”, rather than “nutrition”, and the three factors that contribute to metabolic status are food intake, the amount of body reserves and the rate of energy expenditure ... In this thesis, I tested the general hypothesis that the metabolic hormones and hypothalamic neuropeptides that are known to control food intake also mediate the effect of metabolic status on the activity of the GnRH neurons ... In conclusion, the results from my experiments provide some insight into the mechanisms by which metabolic status affects reproductive activity in male sheep. Plasma insulin, which changes with alterations in metabolic status, appears to play a critical role in the regulation of GnRH neuronal activity. The level of leptin seems to have a permissive role only in lean animals. Orexins acting via OX2 receptors could be involved in the activation of reproductive function following an acute increase in nutrition. However, the neuropeptidergic systems can not be ruled out because they might be involved in very early steps of responses to nutrition.

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46

Passow, Courtney Nicole. "Physiological and transcriptomic aspects of adaptation to extreme environments." Diss., Kansas State University, 2016. http://hdl.handle.net/2097/32867.

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Doctor of Philosophy
Department of Biology
Michael Tobler
Extremophiles are organisms with the ability to survive in environments characterized by strong physicochemical stressors lethal to most other organisms, providing excellent models to further our understanding of life's capacities and limitations to deal with far-from-average conditions. I studied how physiological processes varied among fish residing in starkly different environmental conditions to understand how organisms cope with extreme environments and disentangle the roles of short-term plastic responses and evolved population differences in shaping physiological responses. I used the Poecilia mexicana model, a series of extremophile fish populations that has colonized toxic hydrogen sulfide (H₂S) rich springs and caves, to address three major objectives: (1) I investigated the energetic consequences of life in extreme environments and tested whether predicted reductions in organismal energy demands evolved repeatedly along replicated environmental gradients. (2) I characterized variation in gene expression among populations and organs to test for interactive effects between different stressors and identify potential physiological mechanisms underlying adaptation to H₂S and cave environments. (3) I conducted common garden and H₂S-exposure experiments to test how evolutionary change and plasticity interact to shape variation in gene expression observed in nature. To address these objectives, I measured variation in metabolic physiology and quantified variation in physiological processes through genome-wide gene expression analyses. I found that adaptation to extreme environments directly impacts energy metabolism, with fish living in extreme environments consistently expending less energy overall. Reductions in energy demand have evolved in convergence and were primarily mediated through a life history shift (reduction in body mass). The quantification of gene expression across divergent habitats and organs revealed organ-specific physiological responses in H₂S-rich and cave habitats. Gene expression variation in the relevant genes was primarily shaped by evolutionary change in gene regulation, and ancestral plastic responses play a minor role in causing the observed expression differences between replicated sulfidic and nonsulfidic populations in nature. Overall, my research has implications for understanding the capacities and constraints that shape life in extreme environments and aids in our understanding of modifications in physiological pathways mediating adaptation to elevated H₂S and perpetual darkness.

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47

Carman, Judith Anne. "The metabolic relationship between nutrition and cancer /." Title page, contents and abstract only, 1988. http://web4.library.adelaide.edu.au/theses/09PH/09phc287.pdf.

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48

Hicks, Richard Wayne. "Association of metabolic and hemodynamic variables during exercise in children." Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184264.

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Three investigations were conducted using pulsed Doppler echocardiography (PDE) and oxygen consumption to non-invasively determine the relationship between hemodynamic and metabolic variables from rest through submaximal and maximal exercise in early adolescent males. In the first study, interinvestigator and day-to-day variability of cardiac output measurements at rest and during exercise determined by PDE were analyzed in six junior high school age boys. Four Doppler-derived variables (cardiac output, cardiac index, stroke volume, and stroke index) were not different when calculated by independent investigators and showed the same interinvestigator variability from rest through submaximal and maximal exercise as has been reported at rest in previous validation studies. There was a slight but statistically significant increase in the absolute values of the above hemodynamic variables and simultaneously collected metabolic variables during a second identical test conducted approximately nine days later. A faster adjustment to increasing workrates in the second test could explain this latter finding since supine cycle ergometry is not as familiar an activity as more frequently used modes of exercise testing. It is concluded that hemodynamic measurements using PDE exhibit the same acceptable variability throughout exercise as has been previously demonstrated at rest. In the second study, PDE was used to determine rapid serial measurements of cardiac output during a rapid loading supine cycle ergometer exercise test in twenty-two junior high school age boys. These measurements were compared to simultaneoulsy determined measurements of oxygen consumption. Cardiac output adjusted faster to each new workrate than oxygen consumption. Further analysis of these responses revealed that increases in heart rate (as opposed to stroke volume) were responsible for this rapid adjustment. It is concluded that there is an uncoupling and recoupling of these normally closely related hemodynamic and metabolic variables during the transitional periods between increasing levels of steady-state supine exercise. In the final study, gradual loading and rapid loading supine cycle ergometer protocols were compared in fifteen junior high school age boys. Maximal metabolic measurements and heart rate from each test were not different. Maximal PDE-derived measurements of cardiac output, cardiac index, stroke volume, and stroke index were slightly, but significantly, higher in the gradual loading protocol. It is concluded that a more complete adjustment of cardiac output (reflected by stroke volume) to maximal supine exercise occurs in a more gradual loading protocol than in a rapid loading protocol.

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49

Lee, Stuart M. C. "The elevation of metabolic rate after combined arm-and-leg versus leg-only exercise." Thesis, Virginia Tech, 1992. http://hdl.handle.net/10919/40646.

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Previous investigations have shown that metabolic rate remains elevated for a period of time after the cessation of exercise. While other investigations have examined the effect of intensity and duration of prior exercise, the purpose of this study was to examine the effect of exercise mode and the employment of different muscle masses on the elevation of post-exercise metabolic rate (EPOC). Fifteen non-smoking, physically active females (21.1 Â± 1.3 years; 21.4 Â± 4.6 %BF) volunteered for this investigation. Each subject completed a graded maximal exercise test (GXT) on the Monark 880 cycle ergometer (Max HR=192.5 Â± 2.3 bpm; Max V02=2.68 Â± O.lll/min; Max RPE=19.5 Â± 0.1) from which a heart rate corresponding to 70% V02max was chosen. Subjects then exercised on either a Monark 880 cycle ergometer (LE) or the Schwinn Airdyne (ALE) in random order for thirty minutes at the prescribed heart rate (HR). Exercise bouts were separated from each other and from the GXT by at least 48 hours. Workloads were monitored in five minute intervals and adjusted to maintain the appropriate heart rate. The mean exercise heart rates were 172.5 Â± 2.8 bpm for the LE bout and 170.0 Â± 2.8 bpm for the ALE bout, respectively. Two-way repeated measures ANOVA revealed no significant difference \r >0.05) between exercise treatments in terms of HR or V02. Repeated measures trend analYSis revealed no significant difference in either EPOC or post-exercise heart rate between the two treatments across a one-hour seated recovery period. There was also no significant difference (p>O.05) in excess post-exercise caloric expenditure during the recovery period as a result of the different exercise treatments. Therefore, this suggests that neither exercise modality nor the distribution of work over a larger muscle mass had an effect on EPOC when exercise intensity and duration were held constant.

Master of Science

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50

Ledbetter, John C. "Event Order in the Biathlon Does Not Have an Effect on Metabolic Response." Thesis, University of North Texas, 1990. https://digital.library.unt.edu/ark:/67531/metadc500834/.

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Abstract:

The purpose of this study was to examine the effects of event order on a cycling(C)/running(R) or R/C biathlon. Eight experienced male biathlete/triathletes with a mean age of 24.9 + 4.6 yr formed the sample of the study. Results show no significant interaction effects on oxygen consumption peak, oxygen consumption during steady-state, ventilation, and heart rate when C/R or R/C are performed at 70% oxygen consumption peak for subsequent R and C respectively. These results seem to indicate that the biathlete/triathlete is efficient in both C and R to the extent that event order does not significantly interact with metabolic response in submaximal cycling and running.

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Dissertations / Theses on the topic 'Metabolic Aspects'

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