The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on September 16, 2009). Thesis advisor: Dr. John Thyfault, Dr. Tom Thomas. Includes bibliographical references.

published_or_final_version / abstract / Medicine / Master / Master of Philosophy

Metabolic syndrome includes several metabolic and hormonal disorders, such as abdominal obesity, insulin resistance, and lower blood ghrelin. Women with breastfeeding history exhibit a reduced risk for metabolic syndrome in later life. The purpose of aim 1 was to determine the incidence of metabolic syndrome in low income, overweight/obese women in early postpartum and to assess its relationship to lactation status. It has been found that the incidence of metabolic syndrome is much higher in formula feeding women than that of the breastfeeding ones (44.3% vs. 22.4%, p < 0.01). The breastfeeding mothers had reduced triglycerides (109.07 mg/dl vs. 143.10 mg/dl, p < 001) and elevated serum high-density lipoprotein (HDL)-cholesterol (58.59 mg/dl vs. 51.76 mg/dl, p < 0.01). The goal of aim 2 was to explore associations between ghrelin, metabolic syndrome and infant feeding methods in low income, overweight/obese women in early postpartum. In our study, the breastfeeding mothers in early postpartum had higher plasma ghrelin, as compared to those who formula fed (584.73 pg/ml vs. 450.77 pg/ml, p < 0.01). Additionally, it is found that plasma ghrelin was negatively associated with incidence and numbers of risk factors for metabolic syndrome, before and after controlling for body mass index (BMI). After adjusting for ghrelin in logistic regression analyses, significant relationships between lactation status and metabolic syndrome disappeared. Thus, the protective function of breastfeeding against metabolic syndrome in overweight/obese women in early postpartum may related to the plasma ghrelin values. The purpose of aim 3 was to detect the influence of weight loss on insulin resistance and plasma adiponectin, zinc (Zn), manganese (Mn) and copper (Cu) in low income, overweight/obese women in early postpartum. After an eight-week weight loss intervention, plasma levels of adiponectin, Zn and Mn were significantly enhanced, and plasma concentrations of insulin (7.53±0.56 vs. 6.23±0.49, p <0.01) and insulin resistance (1.84±0.15 vs. 1.44±0.12, p <0.01) were reduced. The increase of adiponectin, Zn and Mn was positively associated with weight reduction. However, the plasma Cu was not significantly affected. The relationships between weight loss and reduced insulin resistance disappeared after adjusting the increases of adiponectin, Zn and Mn during weight loss. Thus, weight loss had beneficial effects on insulin resistance, plasma values of adiponectin Zn and Mn. It is plausible that the influence of weight loss on insulin resistance may be associated with improvements of plasma of adiponectin, Zn and Mn. Collectively, the results of this study demonstrate the important benefits of breastfeeding on prevention of metabolic syndrome in overweight/obese women in early postpartum. This study also emphasizes the influence of ghrelin on risk factors of metabolic syndrome and lactation status. / text

MMed (Urology), Faculty of Health Sciences, University of the Witwatersrand / The metabolic syndrome has recently become one of the major public health challenges and results from the increasing prevalence of obesity. Erectile dysfunction (ED) affects up to half of men over the age of forty. Men with co-morbid disease and risk factors including cardiovascular disease, hypertension, dyslipidaemia and depression all report a higher prevalence of ED. The current study investigated the prevalence of the metabolic syndrome in one hundred men with (ED) presenting to the Male Sexual Dysfunction Clinic at the Johannesburg Hospital. Participants underwent a thorough history taking and examination session which included the International Index of Erectile Function Score. Several fasting biochemistry and hormonal tests were performed. Participants were divided by race into three groups. Data was recorded in EXCEL and reported as mean±std or as a number (frequency). Where applicable, correlation between variables was determined. The prevalence of the metabolic syndrome was 39%, with the highest prevalence (54%) in the group comprising Asian, Coloured and Chinese participants. Eighty percent of participants had moderate-severe (ED), with a mean duration of 3,8 years. Glucose and HbA1c were strong predictors of ED duration. Severity of ED was not influenced by the presence of the metabolic syndrome. Men presenting with ED may represent an ideal patient group to screen for the metabolic syndrome, and therefore for cardiovascular disease, especially for those men within the asymptomatic period.

Thesis (M. Phil.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

Phosphatidylethanolamine (PE) is an important inner membrane phospholipid synthesized de novo by the CDP-ethanolamine pathway and by the decarboxylation of phosphatidylserine. CTP: phosphoethanolamine cytidylyltransferase (Pcyt2) is the main regulatory enzyme in the CDP-ethanolamine pathway and catalyzes the formation of CDP-ethanolamine from phosphoethanolamine. Complete deletion of the mouse Pcyt2 gene is embryonic lethal, and the single allele deficiency leads to development of metabolic syndrome phenotype, including liver steatosis, hypertriglyceridemia, obesity, and insulin resistance. This study aimed to specifically elucidate the effects of dietary methyl group donors betaine and choline supplementation in Pcyt2 heterozygous mice (ETKO). Evidence here shows choline and its oxidized metabolite betaine are responsible for lowering whole body weight, restoring insulin resistance, reducing hypertriglyceridemia, hepatic steatosis, and alleviating adipose and liver tissue inflammation, by restoring hepatic metabolism and gene expression. Collectively, these results establish that the impaired systemic metabolism resulting from Pcyt2 deficiency is a metabolic adaptation that is restored after methyl group supplementation.

Thesis (M.Ph.)--Georgia State University, 2008. / Title from file title page. Ike Okosun, committee chair; Richard Rothenberg, Rodney Lyn, committee members. Electronic text (73 p.) : digital, PDF file. Description based on contents viewed November 25, 2008. Includes bibliographical references (p. 69-73).

Non-nutritive sweeteners (NNS) have been used to replace added sugars in foods/beverages. Research related to NNS consumption and metabolic syndrome (MetS) is of great importance as NNS are often used by individuals who are looking to improve their health. The objectives of this investigation were to determine whether an association between NNS consumption (total and individual types) and MetS exists, and if any of the five risk factors for MetS were more significantly impacted by NNS consumption. Four NNS were included in this study: saccharin, sucralose, aspartame, and acesulfame potassium. Adult participants (n = 125) from Southwest Virginia were recruited for a cross-sectional investigation. Demographics, three 24-hour dietary recalls, and values for MetS (blood pressure, waist circumference, and glucose, triglyceride, and HDL levels) were collected. Statistical analyses included descriptives and multiple linear regressions models. Of the 125 participants, 63 were classified as NNS consumers and 18 met the criteria for MetS. There was a significant positive relationship between MetS and total NNS consumption (p=0.007) and MetS and aspartame (p=0.012). When looking at individual MetS risk factors, waist circumference, triglyceride and glucose values were significantly positively associated with NNS consumption (p≤0.001) and aspartame, sucralose, and saccharin (all p≤0.027). Some limitations to current NNS research were addressed, such as, examining associations between individual NNS types and not using diet soda as a proxy for NNS consumption. More research is needed to address the bias of self-reported data and the lack of randomized controlled trials to inferentially test the impact of NNS consumption. / Master of Science / Non-nutritive sweeteners (NNS) have been used to replace added sugars in foods/beverages because they provide little to no calories. Research related to NNS consumption and metabolic syndrome (MetS) is of great importance as NNS are often used by individuals who are looking to improve their health by reducing added sugar intake. MetS consists of five risk factors: high blood pressure, large waist circumference, high fasting blood glucose values, high triglyceride values, and low high-density lipoprotein. The goals of this study were to determine if there was a relationship between NNS consumption (total and individual types) and MetS, and if any of the five risk factors for MetS were more heavily affected by NNS consumption. Four NNS were included in this study: saccharin, sucralose, aspartame, and acesulfame potassium. For this cross-sectional study, participants (n=125) from Southwest Virginia were recruited. Three 24-hour dietary recalls and values for risk factors of MetS were collected. Of the 125 participants, 63 were classified as NNS consumers and 18 met the criteria for MetS. Based on the data collected, there was a significant positive association between MetS and total NNS consumption and aspartame consumption. When looking at individual MetS risk factors, waist circumference, triglyceride and glucose values were significantly positively associated with total NNS consumption and aspartame, sucralose, and saccharin consumption. Some limitations to current NNS research were addressed, such as, examining relationships between individual NNS types and not using diet soda as the only source for NNS consumption. More research is needed to address the bias of self-reported data and the lack of randomized controlled trials to better test the impact of NNS consumption.

Thesis (Ph. D.)--Michigan State University. Human Nutrition, 2008. / Title from PDF t.p. (Proquest, viewed on Aug. 24, 2009) Includes bibliographical references (p. 141-163). Also issued in print.

Background The optimal exercise load/intensity for exercise programs for individuals with metabolic syndrome (MetS) has not been investigated. One method of determining optimal exercise load is to measure the blood lactate transition threshold (BLTT), referred to as the anaerobic threshold (AT). The first part of this thesis (study 1) investigated the reproducibility of BLTT testing and the consequent determination of AT via the Mader method (Mader et al. 1986) and a modified form of the ADAPT method (Cheng et al. 1992) in patients with MetS. Furthermore, a comparison of the reproducibility of the AT determination using the Mader et al. (1986) method as opposed to the ADAPT method has not been investigated in MetS patients. The effect of specific exercise protocols on the different components of MetS has also not been investigated. Therefore, the second study in the thesis compared the effects on the components of the MetS of an exercise program that uses BLTT (specifically, the AT) to those of a comparable exercise program (not using AT) taken from the literature. The main aim of the study was to design an exercise program that optimized exercise responses and may thus improve metabolic characteristics in individuals with MetS. The third part of the thesis (study 3) focused on the relationship between cardiorespiratory fitness and the components of the metabolic syndrome. This study developed multiple regression models to find the principal variables that associated with peak vi oxygen consumption (VO2 peak) and AT in persons with MetS. Regression models were also developed to investigate whether these variables were associated with the individual metabolic and cardiovascular components of the metabolic syndrome. Methods In study 1, fifteen male patients diagnosed with MetS (age: 43.5 ± 7.52 years) and fifteen healthy, male participants (age: 44.1 ± 6.08 years) each performed a peak oxygen consumption and BLTT test simultaneously using an incremental protocol to exhaustion on a treadmill, at the same daily times, on three different days. Study 2 used three subject groups. One group consisted of ten participants (male, age: 48.3 ± 7.32 years) with MetS that exercised using the walking program of Leon et al. (1979) (MetSL). A second group consisted of ten participants (male, age: 40.8 ± 8.21 years) with MetS that exercised using velocity at AT to set training intensities (MetSV). A third group consisted of ten participants (male, age: 40.2 ± 7.90 years) without MetS that exercised using velocity at AT to set training intensities (Non-MetSV). Training durations and frequency varied from 20 – 90 minutes and 3 -5 days per week respectively. Height, body mass, waist circumference, blood pressure, fasting plasma triglyceride, total cholesterol, HDL-, LDL- cholesterol, insulin levels, VO2 peak and BLTT were measured in all groups before, during and after twenty weeks of exercise. In addition, oral glucose tolerance tests (OGTT) were administered to all participants. 0 min, 30 min and 2 hours plasma glucose and insulin levels were measured during the OGTT. HOMA-IR and insulinogenic indices were also calculated. Nutritional data were recorded at week 0, 8 and 20 of training. vii In study 3, thirty-one males diagnosed with MetS and twenty-four healthy male participants each performed a VO2 peak and a BLTT test. Height, mass, waist circumference, blood pressure, fasting plasma triglyceride, total cholesterol, HDLcholesterol and insulin levels were also measured. In addition, oral glucose tolerance tests (OGTT) were administered to all participants and HOMA indices were calculated. Results There was no significant difference in treadmill velocity at AT determined by the Mader method or the Modified ADAPT method within both groups of study 1 (p > 0.05). The mean treadmill velocity at AT was higher in the healthy compared to the MetS group using both the Mader and the ADAPT method. Regression analysis and ANCOVA in study 1 demonstrated that this difference was largely due to a higher VO2 peak in the healthy group. The study also found an association between VO2 peak and waist circumference. The coefficient of variation of repeat measurements for both the Mader method and the Adapt method was less than 4% indicating good reproducibility. This was confirmed by the typical error method of Hopkins (2000). Study 2 showed that body mass, BMI and waist circumference decreased significantly in all training groups with the training program using AT and the program not using AT showing similar outcomes in these variables among persons with MetS. Velocity at AT also improved in all training groups. While VO2 peak increased (p < 0.05) in both the MetS groups, it did not change significantly in the group without MetS. Similarly, the blood pressure response was favourable in the groups with MetS yet absent in the group viii without MetS. The training group with MetS that used AT was the only group to show significant, positive changes in any of the metabolic parameters (fasting insulin and HOMA). This group also showed the greatest change in the incidence of MetS. In study 3, presence of MetS, waist circumference and AT were found to associate with VO2 peak and VO2 peak was strongly correlated with AT. Age and body mass were found to correlate with fasting glucose, whilst only age correlated with HDL-cholesterol. Age and VO2 peak both correlated with systolic blood pressure but only VO2 peak had a significant association with diastolic blood pressure. Conclusions Study 1 demonstrated that BLTT tests are reproducible in persons with MetS. Study 2 demonstrated that an endurance exercise program using AT to set intensity is effective in eliciting favourable responses in individuals diagnosed with MetS. In addition, the training program using AT elicited the responses with a reduced exercise frequency and intensity. It also improved insulin sensitivity which was not affected by the walking program. The response to the exercise program that used AT was similar in persons with MetS and in persons without MetS, except in the central cardio-vascular adaptations of VO2 peak and in the metabolic parameters of fasting insulin and the HOMA index. Study 3 found that the lower VO2 peak of participants with MetS is associated with their higher waist circumference. The VO2 peak, in turn, was shown to correlate with anaerobic threshold. Therefore, reducing waist circumference in persons with MetS needs to be a focus of intervention programs for such a group. This study also found that both diastolic and systolic blood pressures were associated with cardio-respiratory fitness (VO2 peak). ix This further supports the benefit of increasing cardio-respiratory fitness in persons with MetS. The results of these studies showed that BLTT tests are simple, low-cost, reproducible ways of setting exercise intensity for persons with MetS that can be incorporated in the routine cardio-respiratory fitness assessment of an individual. Furthermore, the determination of AT from such tests can be used to design an individualized exercise program that can “reverse” the effects of MetS.