Dissertations / Theses on the topic 'Academic Metabolism'

Although poorly understood, normal cells and cancerous cells of the same type exhibit different patterns of nutrient consumption, processing and utility of metabolic substrates. Differences in substrate uptake, preference, and alternately emphasized metabolic pathways offer opportunities for selective targeting of cancer versus stroma. This may be accomplished by using a sequential approach of nutrient deprivation and pharmaceutical perturbation of metabolic pathways to inhibit cellular proliferation. The purpose of this study was to investigate the effects of restricting glucose and glutamine concentrations, in vitro, to levels that resemble a potential human fasting state. The mammalian target of rapamycin (mTOR), a mediator of nutrient sensation, was then inhibited with rapamycin in the nutrient-restricted conditions. Because active Akt/mTOR is implicated in cancer cell pro-survival, the hypothesis is that pharmaceutical inhibition of active Akt/mTOR signaling in combination with the stress of restricted nutrient supply will be more effective than nutrient deprivation alone at disrupting metabolic processes to impair cancer cell proliferation and/or pro-survival mechanisms. Untreated and treated conditions were tested to determine if an additive or synergistic effect would result from a sequential insult of nutrient deprivation followed by inhibited mTORC1 signaling. The cell line used for this study was cultivated from a murine pancreatic intraepithelial neoplasia (PANIN) derived from a transgenic mouse with pancreatic tissue-specific expression of constitutively active Akt. The transgene of Akt, isoform 1, contains a myristoyl tag that facilitates co-localization of Akt to the plasma membrane, thereby promoting the activation of this signaling protein.; This aberrantly activated Akt represents a prosurvival condition observed in most cancers, and impacts metabolic balance with increased downstream signaling to metabolic sensors and regulators, including mTORC1. Several methods were used to evaluate changes in metabolic and physiological response to nutrient deprivation and mTORC1 inhibition. These included tetrazolium reduction/absorbance readings to qualitatively evaluate differences in cell proliferation, and Western immunoblots for observing changes in protein expression and phosphorylation. ATP luminescence assays were applied to quantify intracellular ATP content, and citrate synthase spectrophotometry used to quantify specific activity/indicate changes in the TCA/OXPHOS production of ATP. Results from the above methods suggest that, individually, nutrient deprivation and rapamycin treatment share some similar effects on metabolically-related protein phosphorylation and in reducing cellular proliferation. Collectively, nutrient deprivation plus rapamycin treatment, however, resulted in unanticipated metabolic alterations under conditions used for this study, the complexities of which would need to be delineated in future studies.
B.S.
Bachelors
Burnett School of Biomedical Sciences
Molecular Biology and Microbiology

The weightless environment results in atrophy of the anti-gravity muscles. Hindlimb suspension is a model for weightlessness induced atrophy. This study evaluated the effects of hindlimb suspension, microgravity and exercise training followed by suspension on skeletal muscle. Soleus mass, myofibrillar and sarcoplasmic protein content were measured in one to four day hindlimb suspended animals. Protein synthesis was measured by intramuscular injection of ³H phenylalanine with correction for the difference between tRNA and intracellular specific activities. Myofibrillar protein loss was minimal after two days of unweighting but significant after three days. Although sarcoplasmic protein content showed no change, synthesis of both protein pools declined in parallel. Myofibrillar degradation increased during the first three days of unweighting, partially accounting for protein loss. The decline in degradation during day four explained the slower rate of protein loss at this time. Sarcoplasmic protein degradation increased slightly during the first two days of unweighting then declined sharply, thus explaining the sparing of sarcoplasmic proteins. Animals exposed to weightlessness showed soleus atrophy similar to suspended animals. The plantaris and gastrocnemius had reduced growth while the extensor digitorum longus and tibialis anterior grew normally in flight and suspended animals. Insulin stimulated glucose uptake was enhanced in soleus, but not extensor digitorum longus of flight and suspended animals. In situ insulin and IGF-1 stimulated 2-deoxyglucose uptake was greater after six days of suspension. Voluntary wheel training increased soleus mass, protein content and in vivo protein synthesis which plateaued by three weeks. Suspended or trained-suspended animals showed reductions in soleus mass, protein content and synthesis compared to trained animals. However, trained-suspended animals showed higher values for protein content and synthesis compared to suspended animals. In conclusion, these studies show that unweighting atrophy is characterized by decreased synthesis and increased degradation of myofibrillar proteins, and a sparing of sarcoplasmic proteins due to slower degradation. Tail-cast hindlimb suspension may be used as a ground based model to mimic the effects of weightlessness on muscle proteins. Wheel training causes muscle hypertrophy; and although training prior to suspension provides some protection against protein loss, it does not prevent atrophy.

Pyrrolizidine alkaloids are proposed to be metabolized in the liver to reactive pyrrole species, or dehydroalkaloids. These reactive pyrroles are hypothesized to be responsible for pyrrolizidine alkaloid toxicity. This dissertation research has established that dehydroalkaloids are, in fact, metabolites of pyrrolizidine alkaloids. It was first determined that dehydromonocrotaline is produced during hepatic microsomal metabolism of monocrotaline and that it has the ability to bind in vitro with a synthetic thiol-containing resin, Thiopropyl Sepharose 6B. Similarly, synthetic dehydromonocrotaline binds to this resin. Dehydromonocrotaline was identified as a pyrrolizidine alkaloid metabolite based upon its resin cleavage products. When resin-bound pyrrole, synthetic or microsomally generated, was cleaved in a buffered, ethanolic silver nitrate solution, O⁷-ethyl dehydroretronecine was the major product, supporting the suggestion that the pyrrole generated by hepatic microsomes is dehydromonocrotaline. This system was then used to determine the formation of dehydroalkaloids from other pyrrolizidine alkaloids. These other alkaloids--trichodesmine, retrorsine, senecionine and heliotrine--cause toxicity to the liver as well as to extrahepatic organs. Their metabolism in this system reveals that alkaloids which produce extrahepatic toxicity have an increased percentage of reactive metabolites formed by phenobarbital-induced hepatic microsomes. Therefore, this system in vitro can be a good predictor of alkaloids which may produce extrahepatic toxicity in vivo. Trichodesmine is a pyrrolizidine alkaloid that is unique in its neurotoxicity. It is structurally similar to monocrotaline, yet it varies widely in its toxicity. It was determined that trichodesmine is more toxic in the rat than monocrotaline as indexed by LD₅₀ values. The distribution of pyrrolic metabolites reveals that trichodesmine treatment results in brain pyrrole levels 4 times higher than monocrotaline, retrorsine, or control. Histopathologic investigation of trichodesmine-treated animals reveals severe neuronal death in the cerebral cortex. These results suggest that neurotoxicity observed with trichodesmine is a result of pyrrole metabolites reaching the brain, thus providing further evidence for the involvement of pyrrole metabolites in pyrrolizidine alkaloid-induced extrahepatic toxicity.

1,2,3-Trichloropropane (TCP) causes rat hepatic DNA damage in the form of DNA single strand breaks. This damage was dose and time dependent. In vivo ¹⁴C-TCP equivalents covalently bound to hepatic protein, RNA and DNA. Glutathione depletion with L-buthionine-(R,S)-sulfoximine increased binding to protein by 342% while it decreased binding to DNA by 56%. The in vivo binding data suggest a dual role for glutathione in the bioactivation of TCP. In vitro rat hepatic microsomes activated TCP to species which covalently bound to microsomal protein. Rat liver microsomes also bioactivated TCP to the direct acting mutagen 1,3-dichloroacetone. 1,3-Dichloroacetone was identified as the major microsomal protein binding species through conjugation with N-acetylcysteine to form 1,3-(2-propanone)-bis-S-(N-acetylcysteine) which accounted for 87% of all TCP microsomal metabolism. These findings support a role for 1,3-dichloroacetone as a mutagenic metabolite of TCP. Carbon-13 nuclear magnetic resonance was used to identify directly the urinary metabolite of ¹³C₃-TCP (99 atom % enrichment). Urine was investigated directly using proton-decoupled ¹³C and two-dimensional homonuclear correlated nuclear magnetic resonance spectroscopy. Spectral shifts have been assigned to N-acetyl-S-(2-hydroxy-3-chloropropyl)cysteine, 1,3-(2-propanol)-bis-S-(N-acetylcysteine), N-acetyl-S-(2-hydroxy-2-carboxyethyl)cysteine, 2,3-dichloropropionic acid, 2-chloroethanol, ethylene glycol and oxalic acid by comparison to spectra of authentic standards. No unchanged TCP was detected. From the results obtained it is concluded that metabolism of TCP by cytochromes P450 and by glutathione conjugation can result in the formation of reactive metabolites of TCP which may be responsible for TCP genotoxicity.

Thesis (Ph. D.)--University of California, San Diego, 2010.
Title from first page of PDF file (viewed June 3, 2010). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (leaves 141-143).

Human promyelocytic leukemic cells (HL-60) possess well regulated expression of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, acylCoA:cholesterol acyltransferase (ACAT), and receptor-mediated low density lipoprotein (LDL) catabolism, but lack receptor-mediated acetyl-LDL processing. Differentiation of HL-60 cells with tetramyristic phorbol acetate (TPA) is accompanied by the loss of receptor-mediated LDL degradation and no expression of a functionally active scavenger receptor. 1,25-Dihydroxyvitamin D₃ (D₃)-induced HL-60 macrophages possess specific and saturable receptor-mediated binding for LDL, with an apparent K(d) of 29 μg/ml and a B(max) of 219 ng/mg. Receptor-mediated LDL degradation is specific for apoB and apoE containing lipoproteins; it is calcium dependent, and is inhibited by pronase and chloroquine. Differentiation of HL-60 cells with D₃ for 2 days induces a 45-fold increase in acetyl-LDL degradation rate compared to undifferentiated cells. Receptor-mediated degradation of acetyl-LDL is specific for acetyl-LDL, calcium independent, inhibited by chloroquine, pronase and fucoidin treatment, and is not regulated by cellular cholesterol. Acetyl-LDL binding studies demonstrated a K(d) of 36 μg/ml and a B(max) 313 ng/mg. Delivery of cholesterol via receptor-mediated catabolism of LDL or acetyl-LDL results in significant suppression of sterol synthesis and HMG-CoA reductase activity, and significant induction of ACAT activity relative to macrophages incubated with LPDS (P < 0.001). However, receptor-mediated degradation of acetyl-LDL, but not LDL, significantly increases cholesteryl ester content (P < 0.001). D₃-induced HL-60 macrophages incubated with or without LDL for 48 hr exhibited large empty vacuoles with little or no lipid stainable material. In contrast, macrophages incubated with acetyl-LDL exhibited a dramatic increase in lipid stainable material which imparted the macrophages with a foamy appearance. In conclusion, HL-60 cells treated with D₃ for 48 hr undergo activation differentiation assuming the structural and functional characteristics of human monocyte-derived macrophages. Thus, D₃-induced HL-60 macrophages are a suitable in vitro system to study lipoproteins and cholesterol regulation as related to macrophage involvement in atherosclerosis.

Thesis (Ph. D.)--University of California, San Diego, 2007.
Title from first page of PDF file (viewed August 6, 2007). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 147-190).

Thesis (Ph. D.)--University of California, San Diego and San Diego State University, 2009.
Title from first page of PDF file (viewed January 12, 2010). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.

Over the last 30 years data from manned spaceflight missions have indicated that microgravity affects a number of physiological systems including the skeletal muscles. The purpose of the experiments in this dissertation was to examine the influence of 14 days of simulated microgravity on insulin and exercise stimulated glucose utilization in rat hindlimb muscles. To accomplish this aim, male Sprague-Dawley rats (250-325 g) were suspended in a head down position (SUS) so that one or both hindlimbs were non-weight bearing. The results from hindlimb perfusion experiments indicated that glucose uptake rates for the entire hindquarter at both submaximally and maximally stimulating insulin concentrations were significantly higher (p ≤ 0.05) in the SUS rats (77% and 15%, respectively) than the cage control rats (CC), suggesting increases in insulin sensitivity and responsiveness. Insulin sensitivity for ¹⁴C glucose incorporation into glycogen was also increased for the soleus (SOL), plantaris (PL), and extensor digitorum longus (EDL) muscles in the SUS rats. When the suspended (SUS-E) and control (CC-E) rats were exposed to acute treadmill exercise at 80-90% of VO₂ max, hindlimb glucose uptake and its incorporation into glycogen in the absence of insulin were higher in the PL, EDL, and white gastrocnemius (GW) muscles from the SUS-E rats. However, hindlimb muscle responses to insulin appeared to be impaired after exercise for the SUS-E rats when compared to the CC-E rats, especially in the SOL muscle. To examine the influence of non-weight bearing per se on muscles during simulated microgravity, rats were suspended with the left hindlimb non-weight bearing (NWB) and the right hindlimb bearing 20% of pre-suspension body mass (WB). The results indicated that ³H 2-deoxyglucose uptake was significantly higher for the SOL, PL, EDL and GW muscles (21-80%), at a maximally stimulating insulin concentration, in both SUS-NWB and SUS-WB hindlimbs despite the prevention of SOL and PL muscle mass losses in the SUS-WB hindlimbs. Collectively, the results from this dissertation indicate that the suspension of the rat with hindlimbs non-weight bearing leads to enhanced muscle responses to insulin for glucose uptake and metabolism, and suggest that systemic influences may be involved. In addition, exercise induced glucose and glycogen utilization increase to a greater extent in the hindlimb muscles of suspended rats when compared to their controls; but, there was evidence that muscle responses to insulin were attenuated with exercise in the suspended animals.

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Bachelors
Burnett College of Biomedical Sciences
Molecular Biology and Microbiology

Thesis (Ph.D.)--Medical University of Ohio, 2004.
"In partial fulfillment of the requirements for the degree of Doctor of Philosophy in Medical Sciences." Major advisor: Sonia M. Najjar. Includes abstract. Document formatted into pages: v, 217 p. Title from title page of PDF document. Bibliography: pages 158-216.

Experiments were conducted to compare the effect of processing grain sorghum either by dry rolling or steam flaking on the performance and metabolism of high producing dairy cow. In an 80 d trial, following a 14 d pretrial for covariance adjustments, 36 Holstein cows divided in 4 groups were fed a total mixed ration (37 forage:63 concentrate) prepared with one of the following four grains: Steam-rolled corn (CORN), dry-rolled sorghum (DRS), steam-flaked sorghum (SFS) and an equal mixture of DRS and SFS (MIX). Grain comprised 42.2% of diet DM. In the last 14 d of the experimental period a digestibility trial was conducted. There was no difference (PS < .05) in milk, FCM or milk fat production across treatments. Because cows on SFS consumed less DM (P < .05) than those on MIX, the gross efficiency of FCM production was higher, (P < .05) for SFS. Other treatments were intermediate for DM intake and FCM efficiency. Milk protein percentage and production were higher (P < .05) for SFS compared to DRS, while lactose and SNF were higher (P < .05) for SFS compared to DRS, while lactose and SNF percentages were the highest (P < .05) for SFS compared to other diets. Apparent digestibility of starch from SFS was the highest (P < .01) and that from DRS was the lowest while apparent digestibility of the fiber components and of CP were lower (P < .05) for SFS compared to DRS. Improvement in FCM efficiency and milk protein production was probably due to increased starch degradability. In a second experiment, the same diets used in the lactation trial were fed to 4 duodenally cannulated cows in a 4 x 4 Latin square design. Total tract digestibility of starch was higher (P < .05) for SFS than MIX and DRS diets and tended to be more digested in the rumen than starch from other diets. Cows fed SFS also tended to more efficiently convert dietary CP digested in the rumen to BCP and to have higher BCP flow to the duodenum. Cows on the SFS diet had highest (P < .01) fecal pH, tended to have the lowest amount of fecal protein and the highest apparent digestion of N.

The effects of premature weaning at two days of age on cholesterol and lipoprotein metabolism were studied in adult guinea pigs. Both normally (control) and prematurely weaned guinea pigs were fed a non-purified diet (basal diet). At 8 weeks of age control and prematurely weaned animals were divided into three groups, and were fed either the basal diet, or basal diet containing either 0.25% cholesterol or 1.1% cholestyramine for 4 weeks. Prematurely weaned guinea pigs fed the basal diet as adults exhibited a significant increase of 1.7-fold in hepatic 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase activity and a 1.4-fold increase in plasma cholesterol levels, mainly in the low-density lipoprotein (LDL) fraction (P < 0.05). In addition, the number of LDL receptors of hepatic membranes was significantly reduced by 56% in prematurely weaned guinea pigs compared to controls. Mass ratios of core (triglyceride and cholesteryl ester) to surface (free cholesterol, protein, and phospholipid) components of LDL were significantly higher in the prematurely weaned animals relative to normally weaned animals (P < 0.05). However, there was no change in particle size with variation in treatment. In vitro incubation of LDL with high density lipoprotein and cholesterol ester transfer protein demonstrated a 2-fold increase in cholesteryl esters transferred to LDL in the prematurely weaned animals compared to controls. Addition of dietary cholesterol increased plasma and hepatic cholesterol levels, and decreased hepatic HMG-CoA reductase activity and receptor-mediated LDL binding in the control animals. In contrast, prematurely weaned animals did not show a significant increase in plasma cholesterol levels. Cholestyramine intake decreased plasma cholesterol in the normally weaned but not in prematurely weaned guinea pigs. Premature weaning resulted in a significant reduction in hepatic cholesterol levels in animals fed cholestyramine. Receptor-mediated LDL binding increased in animals fed cholestyramine compared to animals fed the basal diet and premature weaning did not alter this response. These data indicate that premature weaning alters in vivo cholesterol metabolism of adult guinea pigs resulting in increased plasma cholesterol levels, hepatic HMG-CoA reductase activity and CETP activity, and decreased levels of hepatic LDL receptors. Premature weaning also alters the regulatory responses to feedback suppression and metabolic induction of plasma lipoprotein cholesterol metabolism.

Studies have shown that hypercholesterolemia is a risk for cardiovascular disease; however, some normocholesterolemic individuals still develop coronary atherosclerosis. This project was undertaken to investigate the association of abnormalities of low density lipoprotein (LDL) metabolism, in the absence of hypercholesterolemia, with the development of coronary artery disease (CAD). Mononuclear leukocytes (MNL), HL-60 cells and 1,25-dihydroxyvitamin D₃-induced HL-60 macrophages were used as model systems to study the effect of an altered LDL composition on cellular lipoprotein and sterol metabolism. LDL and MNL were isolated from patients with and without CAD. The mean rate of LDL degradation was 1.7-fold higher in CAD-MNL than in control-MNL (P < 0.05), independent of the LDL source. The increased LDL degradation rate in CAD-MNL appeared to be due to an increased LDL receptor activity of CAD-MNL and not to an increased CAD-LDL interaction with the receptor since LDL isolated from patients with and without CAD had similar in vitro degradation rates by HL-60 cells and D₃-induced HL-60 macrophages. LDL from CAD patients (CAD-LDL) contained significantly less cholesteryl ester per particle than LDL from control subjects (Control-LDL). The ability of CAD-LDL and Control-LDL to regulate sterol and lipoprotein metabolism was compared in HL-60 cells. The results indicate that CAD-LDL exhibited reduced abilities to suppress receptor-mediated LDL degradation and to activate acyl-CoA:cholesterol acyltransferase as compared to Control-LDL. There was no significant difference in the rate of sterol synthesis between cells treated with CAD-LDL and Control-LDL. The data support the hypothesis that cholesteryl ester-poor CAD-LDL exhibits a decreased ability to down-regulate LDL receptor activity which could in part account for the observed increase in LDL degradation by MNL from CAD patients. A noncompetitive enzyme-linked immunosorbent assay (ELISA) was developed to measure plasma apolipoproteins (apo) A-I and B. The results indicate that a reduced plasma apo A-I level was associated with CAD patients even if there were no significant differences in the levels of high density lipoprotein cholesterol when compared with individuals without CAD.

Diets consisting of non-purified guinea pig diet or non-purified guinea pig diet supplemented with either 1.1% of the bile acid binding resin cholestyramine or 0.25% cholesterol were fed to dams from the first day of conception. Whole body rates of endogenous cholesterol synthesis and 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase mRNA levels were determined at 0, 40 and 60 days of gestation in the dam and fetus. Sterol synthesis studies indicated that maternal hepatic cholesterol synthesis was reduced 87% by dietary cholesterol and was increased 2.9-fold with cholestyramine feeding. The pattern of fetal hepatic and peripheral tissue cholesterol synthesis rates during development indicated that synthesis was highest at 40 days gestation, and by 60 days was reduced to levels similar to that found in the adult. Cholesterol synthesis rates in the fetus were relatively insensitive to dietary manipulation; however, maternal cholestyramine treatment did result in a 1.4-fold increase in fetal carcass cholesterol synthesis at 60 days gestation. To determine whether regulation at the level of feedback suppression or induction of steady state RNA levels were also present in the fetal organism, mRNA levels for HMG-CoA reductase were quantified in the maternal and fetal liver. In these studies the guinea pig was shown to have two reductase mRNA species of 4.5 and 3.2 kb, similar to transcript sizes identified for the hamster, rat and Drosophila. Although nearly equimolar in the 40 day gestation fetus the 3.2 kb transcript predominated at 60 days. Dietary treatment had only minor effects on fetal reductase mRNA levels at 40 days gestation; however, at 60 days gestation, fetuses from cholestyramine-fed dams had elevated levels of reductase mRNA and fetuses from cholesterol fed dams had reduced levels of reductase mRNA. These studies indicate that maternal cholesterogenic systems maintain responsiveness to dietary regulation during pregnancy at both the level of sterol synthesis rates and HMG-CoA reductase mRNA levels. These findings also indicate that it is possible to influence those mechanisms which modulate cholesterol homeostasis prenatally. Further studies will be required to determine if such effects extend into the post-natal period and beyond.

Thesis (Ph.D.)--Medical College of Ohio, 2004.
In partial fulfillment of the requirements for the degree of Doctor of Philosophy in Medical Sciences. Major advisor: Sonia Najjar. Includes abstract. Document formatted into pages: v, 167 p. Bibliography: pages 117-165.

The influence of dietary copper deficiency on hepatic apolipoprotein A-I synthesis and mRNA abundance, as well as on whole body energy metabolism was examined in rats. Weanling male Sprague-Dawley rats were divided into two dietary treatments; copper-adequate (6.0 mg Cu/kg diet) and copper-deficient (0.6 mg Cu/kg diet). After 6 weeks of treatment, an increase in intravascular apolipoprotein A-I pool size was observed in copper-deficient rats. In part I, in vivo hepatic apolipoprotein A-I synthesis was determined by the injection of flooding dose of [³H]phenylalanine and measurement of the incorporation of [³H]phenylalanine into newly synthesized immunoprecipitable apolipoprotein A-I in liver homogenates as well as plasma. A pulse-chase study was designed using [³H]phenylalanine, to determine the in vitro hepatic apolipoprotein A-I synthesis and intracellular degradation in freshly isolated hepatocytes. Furthermore, hepatic apolipoprotein A-I mRNA abundance was determined by dot blot analysis. In part II, rats were individually housed in metabolic cages within indirect calorimetry units to study their energy metabolism. Total body composition was determined by total body electrical conductivity. Copper deficiency resulted in a specific 2-fold increase in hepatic apolipoprotein A-I synthesis and secretion. In vitro hepatic intracellular degradation was small and not affected by copper status. The hepatic apolipoprotein A-I mRNA abundance was increased by 28% when corrected for liver-to-body weight ratio in the copper-deficient rats. Copper deficiency resulted in a distinct shift in energy substrate utilization from carbohydrate to fat. Body weight gain and net energy retention were reduced as a result of copper deficiency. Total body composition analysis showed a reduction in percent fat mass in the copper-deficient rats. The present data suggest that copper deficiency results in an increased cellular demand for lipids as energy substrate in order to maintain an adequate energy balance. The observed increase in hepatic apo A-I synthesis may be a result of an increased demand for HDL formation to sustain an increased flux of lipid substrates between the liver and peripheral tissues, resulting in the observed hypercholesterolemia in copper-deficient rats.

Thesis (Ph. D.)--Medical College of Ohio, 2004.
"In partial fulfillment of the requirements for the degree of Doctor of Philosophy in Medical Sciences." Major advisor: Sonia Najjar. Includes abstract. Document formatted into pages: iv, 181 p. Title from title page of PDF document Includes bibliographical references (p. 123-180).

Use of induced hypothermia for the purpose of lowering intracranial pressure and preserving neuronal function has increased as research data reveals a trend of positive outcomes in patients treated with this therapy. Recently induced hypothermia following cardiac arrest due to ventricular fibrillation has been deemed successful. Current research has expanded to evaluate the effectiveness of induced hypothermia as a treatment modality for severe stroke and head trauma. In spite of its efficacy, complications exist with this treatment modality. The purpose of this literature review is to examine potential complications secondary to induced hypothermia and highlight the nurse's role in managing patient care. At the present, patient protocols for induced hypothermia are lacking. The success of treatment is largely dependent on the skill of the healthcare team to prevent further harm and enhance therapeutic outcomes by providing astute assessment and management of complications in patients undergoing induced hypothermia. The desired outcome of this review is to promote integration of research in the development of evidence-based protocols for induced hypothermia.
B.S.N.
Bachelors
Nursing
Nursing

The Glycine and Proline Reduction systems are two of the best characterized selenoenzymes in bacteria and have been found to occur in a wide variety of clostridia [1-5]. These enzymes are utilized to reduce glycine or D-proline to obtain energy via substrate level phosporylation or membrane gradients, respectively [6, 7]. This includes the pathogens C. difficile and C. botulinum [5, 8]. Strains of C. difficile are activate toxigenic pathways whenever either of these pathways is active within the cell [5, 8]. Though evolutionary studies have been conducted on ammonia producing bacteria [9] none has been done to directly characterize these two system by themselves. This includes an understanding of whether or not this system is transferred between organisms, as many of the clostridia that are to be studied are known to have an “open genome.” [8, 10] With this information we were able to generate a phylogenic model of the proline and glycine reduction systems. Through this analysis, we were able to account for many clostridial organisms that contain the system, but also many other organisms as well. These included enterobacteriaceae including a strain of the model organism, Escherichia coli. It was further concluded that Glycine Reductase was a much less centralized system and included a wide range of taxa while Proline Reductase was much more centralized to being within the phyla of firmicutes. It was also concluded that the strain of E. coli has a fully functional operon for Glycine Reductase.
B.S.
Bachelors
Burnett School of Biomedical Sciences
Molecular Biology and Microbiology

Diabetes is a condition that is primarily self-managed and lifestyle modifications such as diet, exercise, and weight management are necessary to reduce morbidity and mortality. Motivation to implement lifestyle modifications through self management is an integral part of disease management and studies have shown group medical visits are more effective than individual appointments in this patient population. The purpose of this project was to develop, implement and evaluate an evidencebased group medical visit program for up to a maximum of 8 adult patients with type 2 diabetes in a family practice setting for six months. Seven participants with abnormal A1C results accepted the invitation to attend group medical visits. Here surrounded by peers with the same diagnosis, they were able to learn and discuss methods to self manage their type 2 diabetes. At the conclusion post survey results indicate positive change in some lifestyle behaviors and improvement with hemoglobin A1C. However there was no improvement in weight management. A cost analysis reveals group medical visits may generate a small profit when compared to individual visits. Group medical visits may offer an effective means to motivate patients to make lifestyle change to reduce risk.

The rumen microbiome constitutes a unique genetic resource of plant fiber degrading microbial enzymes that could be used for agricultural and industrial purposes. Anaeromyces mucronatus is a poorly characterized anaerobic lignocellulolytic fungus in the rumen. This thesis aimed at better understanding A. mucronatus YE505 and the particle associated rumen microbiota based on transcriptomic and metatranscriptomic approaches. High quality RNA was isolated from the fiber-associated rumen sample based on an improved RNA extraction method. A transcriptomic study was performed to investigate the expression of the fiber degrading system of A. mucronatus YE505, and the functional diversity of the fiber-associated eukaryotes from the rumen of muskoxen (Ovibos moschatus) was explored by a metatranscriptomic study. Much carbohydrate degradation related protein modules were detected. This study established effective approaches to characterizing the functional contents of rumen eukaryotic microbiome as well as rumen fungi, and identified several candidate genes that merit further investigation.
xiv leaves : ill. (some col.) ; 29 cm

Thesis submitted in fulfilment of the requirements for the degree Doctor of Technology: Biomedical Technology in the Faculty of Health and Wellness Sciences at the Cape Peninsula University of Technology 2014
According to the World Health Organization, cancer is the leading cause of death in the developed world, while it is the second leading cause of death in the developing world. In particular, liver cancer is the fifth most commonly diagnosed cancer in men, however, it is the second most frequent cause of death, responsible for an estimated 700,000 deaths annually. General limited access to health services, including treatment and the overall management of cancer in developing countries often contribute to the increased mortality rates when compared to developed countries. For centuries, medicinal plants have been used to prevent, and to a certain extent, treat cancer as a readily available and affordable alternative. In many instances, the curative or preventative claims still remain anecdotal. However, increasing evidence suggest that polyphenolic components of plants possess antioxidant activities, which are credited with curative/beneficial properties of medicinal plants. The curative properties could either be related to the primary compounds present in the plant itself, or the bio-activation products of plant components affecting hepatic drug metabolising and antioxidant enzymes systems related to carcinogen metabolism and maintaining oxidative homeostasis, respectively. Similarly, chronic consumption of medicinal plants could also result in hepatotoxicity, either caused by the primary plant components or bio-activation products. Due to these observations it is paramount to understand the mechanisms involved in the metabolism of plant components to critically assess beneficial versus potential harmful properties associated with chronic consumption. The focus of the current study was aimed at elucidating the bio-activity of four multipurpose indigenous plants to Southern Africa, i.e. Adansonia digitata, Agathosma betulina, Siphonochilus aethiopicus and Myrothamnus flabellifolius. Traditionally, A. digitata has been used as an immunostimulant, anti-inflammatory and analgesic agent, while also as an antipyretic agent in the treatment of diarrhoea and dysentery. Similarly, traditional medicinal uses of A. betulina include treatment cholera, haematuria, calculus, kidney diseases, as well as infections of the bladder, urethra, and prostate among others. S. aethiopicus was traditionally employed to treat infections associated with pains and fevers, whereas M. flabellifolius served as treatment of conditions ranging from respiratory ailments, backache, kidney problems, haemorrhoids, chest pain, and asthma. In the first part of this study, the polyphenolic contents and antioxidant capacities of the four plants were characterised. The emphasis was placed on using different solvents, namely water, ethanol and acetone for the extraction of the plant material and different methodologies to assess the antioxidant contents and -capacities of the various extracts as both these factors can influence the outcome. When considering the antioxidant contents, total polyphenols, flavanols, and flavonols of the different solvent extracts prepared from the four plants were determined, whereas three different assays were used for the antioxidant capacities, i.e. oxygen radical absorbance capacity (ORAC), trolox equivalent antioxidant capacity (TEAC) and ferric-reducing antioxidant power (FRAP) assays. The A. digitata acetone extract had the highest (7.121 mg gallic acid equivalent (GAE)/milligram (mg) soluble solids), whereas the water extract of the same plant had the lowest total phenolic content (0.008 mg GAE/mg soluble solids). In general, the acetone extracts demonstrated the highest total polyphenol, flavanol, and flavonol contents, followed by the ethanol extracts, with the water extracts having the lowest contents. M. flabellifolius was the only distinct deviation from this rule, where the water extract demonstrated the highest total polyphenol content. Considering antioxidant capacities, the acetone extracts provided the highest antioxidant capacities for all plants when assessed using the TEAC (8.56-32.68 milimole (mmole) trolox equivalent (TE)/mg soluble solids) and FRAP (5.69-37.39 mmole ascorbic acid equivalent/mg soluble solids) antioxidant assays, with the exception of M. flabellifolius where the water extract demonstrated the highest activity (22.73 mmole ascorbic acid equivalent/mg soluble solids). Antioxidant capacity determinations with TEAC and FRAP assays followed similar patterns, which were different from capacities determined by the ORAC (0.46-533.54 mmoleTE/mg of soluble solids) assay. Corroborating the antioxidant content findings, the acetone extracts also demonstrated the highest antioxidant capacities (140.41-533.54 mmoleTE/mg of soluble solids), followed by ethanol (94.62-151.29 mmoleTE/mg of soluble solids) and water (0.46-134.02 mmoleTE/mg of soluble solids). Only M. flabellifolius (TEAC and FRAP) and S. aethiopicus (FRAP) deviated from this trend. Correlations between the polyphenolic contents and antioxidant capacities indicated that acetone and ethanol were more effective in extracting polyphenolic compounds than water, while also providing extracts with superior antioxidant activities. Furthermore, ORAC assay was the antioxidant capacity determining assay of choice for the aqueous plant extracts, whereas the TEAC and FRAP assays were more suitable when determining the antioxidant capacities of the acetone and ethanol plant extracts. These results confirm the notion that no single assay can comprehensively determine the antioxidant activities of plant extracts and that a battery of assays should be used, as the various antioxidant capacity determination techniques use different substrates with different targets for measurement. The second part of this study comprised an in vivo experimental animal model to assess the potential toxicity, antioxidant status and modulation of the hepatic phase 2 drug metabolising enzymes following chronic consumption of the various plant extracts in male Fisher rats. Rats consumed aqueous extracts of the various plants (2% and 5% (w/v)) as the sole source of drinking fluid for 90 days, and the serum chemical pathology parameters for monitoring liver and kidney function conducted. These included alkaline phosphatase (ALP), aspartate transaminase (AST), alanine transaminase (ALT), total iron (Fe), and creatinine (CREA). Parameters for blood and hepatic redox status included total polyphenols, ORAC, reduced glutathione (GSH), oxidised glutathione (GSSG), their ratio (GSH:GSSG), conjugated dienes (CD) and thiobarbituric acid reactive substances (TBARS). Assessment of the phase 2 hepatic xenobiotic metabolising enzymes included glutathione S-transferase (GST)  and activity in the cytosolic fraction and, UDP-glucuronosyltransferase (UDP-GT) activity in liver microsomes. When considering the liver and kidney function none of the plant extracts induced any significant toxicity, while 2% A. digitata significantly increased serum Fe. When considering the redox status, the whole blood and liver samples yielded similar results, with significant decreases in oxidised glutathione (GSSG) in rats consuming the 2% M. flabellifolius (82.76 mole/L) and 5% A. digitata (90.42 mole/L) with a resultant significant increase in the glutathione redox status (GSH:GSSG ratio of 5.69 and 5.64, respectively) when compared to rats consuming water (4.77). The GSH:GSSG ratio was also significantly increased by consumption of 2% A. betulina (8.45) and 5% S. aethiopicus (5.99). The consumption of all plant extracts, except 5% A. betulina and M. flabellifolius, significantly increased lipid peroxidation in the plasma CDs assay. These results indicated an increased antioxidant capacity in the liver with/without an associated reduced cellular oxidative stress status, which could be interpreted as a reduced susceptibility to oxidative damage. When considering the phase 2 hepatic enzymes, none of the plant extracts caused any significant changes in GST, GST or UDP-GT activities. The third part investigated the chemoprotective properties against cancer promotion in the liver utilising diethylnitrosamine (DEN) as cancer initiator and maize culture material of Fusarium verticillioides, containing the fumonisin B mycotoxins, as promoters in male Fischer rats. The rats consumed 2% (w/v) aqueous extracts of A. digitata, A. betulina, and S. aethiopicus over 28 days after cancer initiation and liver sections subjected to glutathione-S-transferase placental form positive GSTP+ staining and pre-cancerous liver foci categorised according to size. In addition, blood and liver analyses were done as described in the chronic feeding study above. Consumption of the A. digitata and, to a certain extent, S. aethiopicus extracts, altered the oxidative stress status in the liver as indicated by the increased lipid peroxidation, as determined by significantly increased liver CDs and the decreased GSH:GSSG ratio in the blood. This can be related to a subchronic toxicity due to the high total polyphenol intake as mentioned above. These underlying sub chronic toxic effects of A. digitata and S. aethiopicus are likely to be responsible for the observed inhibitory effect on the proliferation of GSTP+ minifoci in the liver. Hepatic phase 2 metabolising enzyme activities were not significantly altered by A. digitata and S. aethiopicus consumption, while GST activity was significantly increased by A. betulina treatment. Based on the findings of the current study, aqueous extracts of A. digitata, A. betulina, and S. aethiopicus may serve as hepatoprotectors with a potential to modulate liver carcinogenesis, specifically cancer promotion. To our knowledge, no other studies have attempted to describe the possible chemoprevention mechanisms of these indigenous medicinal plants. Assessments of phase 1 hepatic enzymes and other antioxidant enzymes are suggested for future studies to further describe biochemical and molecular mechanisms associated with consumption of these extracts. Additionally, identifying main compounds present in the plant extracts could culminate in development of drugs and novel nutraceuticals. It is also recommended that increasing concentrations of the plant extracts and/or the ethanol extracts to be used in future studies to better describe dose-responses of the different plants in liver carcinogenesis.

Sucralose is a zero calorie sweetener developed and manufactured by Tate and Lyle Sweetener Company in the 1980’s. They sell the sweetener compounded with maltodextrin and dextrose under the brand name Splenda®. Sucralose was developed as a low cost artificial sweetener that is non-metabolizable in humans and can withstand changes in pH and temperature. It is not degraded by the waste water treatment process. Since the molecule can withstand heat, acidification and microbial degradation it is accumulating in the environment, and has been found in waste water, estuaries, rivers and the Gulf Stream. The highest concentration of environmental sucralose detected to date is 300 ng/L (Torres et al., 2009). Our lab has isolated six bacterial species from areas that may have been exposed to sucralose, given that sucralose has been detected throughout the aquatic environment (Mead et al., 2009). These isolates were cultured in the presence of sucralose looking for potential sucralose metabolism or growth acceleration. Sucralose was found to be nonnutritive, and we found bacteriostatic effects on all six isolates. This inhibition was directly proportional to the concentration of sucralose exposure. The amount of the growth inhibition appears to be species specific. The bacteriostatic effect may be due to a decrease in sucrose uptake by bacteria exposed to sucralose. We have determined that sucralose inhibits invertase and sucrose permease. These enzymes cannot catalyze hydrolysis or be effective in transmembrane transport of the sugar substitute. As sucralose builds up in the environment we must consider it a contaminant due to its bacteriostatic effect. Sucralose may also destabilize or shift the compositions of the bacterial communities in microenvironments such as the mammalian gut.

Obesity is a serious health concern in modern society. One way to reduce caloric intake is with nonnutritive sweeteners (NNS). However, recent research suggests they may be compounding the obesity problem. Nonnutritive sweeteners have been linked to increased body mass in a few studies and may be a barrier to effective weight management for some individuals. Under the framework of the health belief model, the research question was: Does this pattern of NNS-BMI covariance exist in young adults at the University of North Florida and, if so, are there other dietary or activity differences that might partially explain this relationship? A sample of 113 students completed an online survey based on the Youth Risk Behavior Surveillance Survey to answer this question. Their responses quantified BMI, activity level estimates, NNS intake, and produce consumption. There was a no trend of covariance between BMI and NNS intake overall. However, there was a significant relationship between length of NNS usage and both BMI (p<0.01) and NNS intake (p<0.05). A positive correlation also existed between NNS usage and fruit and vegetable intake (p<.005). Weight variability was positively related to NNS due to the maintenance of previous weight loss (p<0.005). There was no correlation between NNS and activity. There is a tendency to have a higher BMI the longer NNS is consumed. This pattern does not appear to be explained by nutrient intake or activity. However, it may be due to increased tolerance towards sweets over time. Nurse practitioners can make recommendations that facilitate healthy behaviors amongst their patients. Therefore, this is an important issue for advanced practice nursing.

Thesis (M. Tech.) -- Central University of Technology, Free State, 2007
Cerebrovascular disease and coronary heart disease (CHD) are of the most important causes of morbidity and mortality amongst South Africans. The risk factor prevalence for stroke and CHD becomes altered by changes in lifestyle, including diet. In general it is suggested that lifestyle management should be the first choice when having to treat patients with increased cardiovascular risk. The prudent low-fat, high-fibre diet is regarded as an apparently healthy diet. It is suspected that this diet is effective for the control of known coronary risk factors as well as raised clotting factors. Research studies have shown the addition of dietary fibre to the diet as a promising therapeutic agent for the limited control of known coronary risk factors. The physiological effects of dietary fibre in humans are significantly influenced by the degree to which fibre is fermented in the colon. Fermentation results in the production of short-chain fatty acids (SCFAs); acetate, propionate and butyrate. The aim of this study was to examine the possible effects of different combinations of short-chain fatty acids on some metabolic risk markers. In this study a group of westernised African male volunteers was recruited and randomly assigned to three groups. Group one received a placebo. Group two received a supplement containing 50% acetate and 50% propionate. Group three received a SCFA supplement in the ratio of 70% acetate, 15% propionate and 15% butyrate. Supplementation was sustained for a period of six weeks. Blood samples were drawn during the different visits. At baseline the study group represented a group of black African men without any apparent metabolic or physical abnormalities. All measured variables fell within the normal range. In the placebo group, there was a statistically significant decrease in plasma fibrinogen levels from baseline to the end of supplementation. In the acetatepropionate supplement study group a statistically significant decrease in factor VIII (from 91.1 ± 11.2 to 90.9 ± 8.3%, respectively), and ATIII (from 114.3 ± 13.1 to 108.34 ± 9.5%), as well as a statistically significant decrease in low-density lipoprotein cholesterol (LDL-C) from 3.10 ± 0.79 to 2.64 ± 0.73 mmol/L. The significant increase in %HDL-C from 26.3 ± 6.5 to 30.2 ± 9.3% should also be noted. Both triglycerides (8%) and plasma fibrinogen (2%) showed a statistically significant increase. However, these changes are of no clinical significance. For the high-acetate supplement study group (with the addition of butyrate), a statistically significant decrease in factor VII (from 102.5 ± 13.7 to 101.1 ± 6.4%), VIII (from 92.6 ± 12.8 to 87.6 ± 6.0%), ATIII (from 109.2 ± 16.0 to 103.0 ± 9.9%) as well as fibrin monomer concentration (from 13.9 ± 2.2 to 12.1 ± 3.6 mg/L), were measured. Fibrin network compaction increased significantly from 14.2 ± 4.6 to 13.7 ± 4.0%. Other changes include a statistically significant increase in the serum-TC of 4.2%. From the results it is evident that the acetate-propionate supplement, with exclusion of butyrate, has a beneficial effect on metabolic parameters when compared to a highacetate- propionate supplement. The results do provide evidence of a possible therapeutic application for the propionate-acetate containing supplement. The specific mechanism should, however, still be investigated. It can be concluded from this study that acetate, propionate and butyrate each have different effects on human metabolism. It is evident that the use of a mixture of acetate and propionate may have a beneficial effect on patients at risk of developing CVD. Further studies that investigate the optimum ratio of these two products may lead to the development of a naturally derived therapeutic product for the prevention or treatment of CVD in black African men, as well as the population at large.

Objectives: To examine variation in clustered metabolic risk (cMetS) in adolescents classified as not overweight/active (NOA), not overweight/not active (NONA), overweight/active (OA), and overweight/not active (ONA). Background: While studies to date have shown that children and adolescents who meet the current physical activity (PA) recommendations and maintain a healthy body weight demonstrate significantly lower cardiometabolic risk, there are some studies that suggest the relationship between PA and metabolic risk may be mediated by adiposity. Methods: The sample included adolescent participants (n=875; 12-17 years) of the 2007-2012 National Health and Nutrition Examination Survey (NHANES). The cMetS score included triglycerides, high-density lipoprotein cholesterol, fasting plasma glucose, and mean arterial pressure. Age- and sex-specific body mass index (BMI) percentiles were utilized; overweight was defined as BMI percentile ≥ 85th. Activity data included self-reported frequency of moderate-to-vigorous PA. Adolescents reporting ≥ 60 min/day of PA were considered “active”. General linear models, adjusted for age, sex, and race-ethnicity, were used. A six-year fasting sample weight was applied to the analyses in order to ensure representativeness of the data. Results: The cMetS scores were significantly (p Conclusions: The cMetS scores were higher in OA and ONA adolescents when compared to those classified as NOA. Whereas only ONA males demonstrated significantly higher cMetS score when compared to the NOA referent, both OA and ONA cMetS scores (vs NOA) were significantly higher in females.

Metabolic hormones and their axes, including the target tissues and receptors, regulate the tissue specific utilization of nutrients with in the body. The purpose of this research was to understand the hormonal control of complex nutrient partitioning mechanisms involved in young, growing animals. Specifically, this involved the investigation of metabolic hormones and the regulation of growth in two common species of phocids (true seals): harbor seal (Phoca vitulina) and Northern elephant seal (Mirounga angustirostris) pups. This longitudinal study examines young phocids from nutritional nadir through realimentation (realimentation) to investigate how metabolic hormones involved in both food intake and nutrient partitioning change with respect to nutritional state. To investigate the role of metabolic hormones during realimentation in a small phocid seal, chapter 2 focuses on the changes in the somatotropic axis and ghrelin during a 10-week period of realimentation following nutritional nadir. Chapter 3 focuses on the application of the results of previous research and the second chapter of this thesis to a specific experimental feeding project. Chapter 4 focuses on the response to changes in nutritional status in the fasting adapted NES. Given the changes in metabolism and priority of nutrient utilization associated with transitioning from a nursing neonate to a fasting adapted juvenile, NES provide a unique opportunity to assess the effect of age on the response to realimentation. Overall, this research will further expand the understanding of tissue specific demands and the effect on endocrine response to realimentation. By incorporating assessments of metabolic changes based on nutrition as well as age, this study will expound on how metabolic hormones are involved in regulating the trade-off between adipose and lean tissue development in this unique taxon.

The purpose of this integrated review of the literature was to explore the effects of social support on diabetes-related stress, conflict, and metabolic control in adolescents with type 1 diabetes mellitus (T1DM). Social support was examined in four subgroups: adolescents with T1DM, family caregivers, peers, and teachers. Relevant findings in the literature revealed a significant deficiency of research devoted to adolescent males with diabetes as well as fathers as primary and secondary caregivers. Studies highlighted the importance of fostering autonomy and positive self-image in adolescents with T1DM and described effective interventions to improve diabetes-related stress, reduce disease-related conflict, and improve metabolic control. Findings suggested that nurses caring for adolescents with T1DM and their families should foster positive, open communication, while identifying barriers to problem solving, coping, stress, and optimal glycemic control. Interventions that educate caregivers and peers on how to better communicate and provide support are critical in fostering positive psychological and physiological outcomes in the adolescent with T1DM. The findings of this study may provide guidance in the way that nurses assess, identify, and counsel adolescents with TIDM regarding their disease management and access to support systems.
B.S.N.
Bachelors
Nursing
Nursing

THESIS SUBMITED IN FULFILMENT OF THE REQUIREMENT FOR THE AWARD OF THE DEGREE OF DOCTOR OF TECHNOLOGY OF BIOMEDICAL TECHNOLOGTY IN THE FACULTY OF HEALTH AND WELLNESS SCIENCES AT THE CAPE PENINSULA UNIVERSITY OF TECHNOLOGY SUPERVISORS: PROF T.E. MATSHA PROF R.T. ERASMUS DR A. ZEMLIN SUBMITED DECEMBER 2013
Introduction: Cardiovascular diseases (CVD) have become the leading cause of morbidity and mortality amongst the global population. Originally thought to be a health burden of high income countries, the prevalence is rapidly increasing in developing countries. For example, in 2008, an estimated 17.3 million died from CVD, and 80% of these (13.8 mil) were from low to middle income countries. Epidemiological data on CVD in Africa is scanty and of poor quality and national vital registration is available in only 5% of Africa’s 53 countries. Furthermore, data on CVD risk amongst the South African population and specifically the mixed ancestry community is poorly described. The increasing global population of people with CVD has been largely attributed to increasing rates of determinants and risk factors which include obesity, metabolic syndrome (MetS), type 2 diabetes mellitus (DM) and chronic kidney diseases (CKD). The prevalence of DM in South Africa is known to be on the rise with more affected communities being South African Asians followed by coloureds. Aims and objectives: The aim of this study was to determine the CVD risk profile of the Bellville South community during a baseline and three year follow-up study, by assessment of known risk factors, MetS, type 2 DM, obesity and CKD. Methods: Participants for this study were drawn from an urban community of the Bellville South suburb of Cape Town. At baseline (January 2008 and March 2009) 946 individuals aged 16 to 95 participated. All participants received a standardized interview and physical examination during which anthropometric measurements were performed three times and their average used for analysis: weight (kg), height (cm), waist (cm) and hip (cm) circumferences. Body Mass Index (BMI) was calculated as weight per square metre (kg/m2). A blood sample was obtained from all participants after an overnight fast for the determination of biochemical profiles: glucose, glycated haemoglobin, creatinine, total cholesterol, high density lipoprotein cholesterol (HDL-C), triglycerides and low density lipoprotein cholesterol (LDL-C) which was calculated using Friedewald’s formula. Kidney function test was assessed through estimated glomerular filtration rate (eGFR) using the cockcroft-Gault and MDRD equations. Blood pressure was measured according to the World Health Organisation (WHO) guidelines. Participants with no history of doctor diagnosed DM underwent a 75 g oral glucose tolerance test as recommended by the WHO. Metabolic syndrome was determined using JIS, NCEP ATPIII and IDF criteria. The follow-up examination was conducted in 2011 (3 years from vii baseline) using similar procedures. A total of 198 participants formed the follow-up cohort whose measurements were compared to those of the baseline. Finally, the prediction and processes/progression of the risk factors were determined. Results: At both baseline and follow-up studies, females had a higher BMI compared to their male counterparts. The crude prevalence of type 2 DM, including the previously diagnosed type 2 DM was 28.59% (age-adjusted = 33.5%, 95%CI: 30.01 – 36.92), and that of undiagnosed type 2 DM was 17.8% (age-adjusted = 12.4%, 95%CI: 9.8 – 14.8). The overall prevalence of CKD was 28.7% (269) and was higher in females (31.4%) compared to 20.2% in males. MetS was present in 46.5% of the participants. Gender-specific prediction for CVD risk calculated using the 30-year CVD interactive risk calculator showed that high CVD risk was present in normoglycaemic and younger subjects (under 35 years). At follow-up, the cumulative incidence of progression in glucose tolerance status was: 16.2% (32 participants including 11 with new-onset diabetes), and increased in a stepwise fashion with the number of components of MetS. Between baseline and 3-year evaluation glomerular filtration rate (eGFR) increased by 8.7 ml/min (95% confidence interval: 6.9-10.7), reflecting variables trajectories across baseline strata of kidney functions. Conclusion: Given the findings of this study and the estimated increases in the determinants and risk factors of CVD in the mixed ancestry population of South Africa this trend may continue to worsen if current trajectories do not change.

Thesis (M.P.H.)--University of Texas Health Science Center at Houston, School of Public Health, 2008.
Source: Masters Abstracts International, Volume: 46-05, page: 2641. Advisers: Jan Bressler; Raol Caetano. Includes bibliographical references.

Polycyclic aromatic hydrocarbons (PAH) are important environmental pollutants originating from a wide variety of natural and anthropogenic sources. Because many of them are highly suspect as etiological agents in human cancer, chemical analysis of PAH is of great environmental and toxicological importance. Current methodology for PAH follows the classical pattern of sample preparation and chromatographic analysis. Sample preparation pre-concentrates PAH, simplifies matrix composition, and facilitates analytical resolution in the chromatographic column. Among the several approaches that exist to pre-concentrate PAH from water samples, the Environmental Protection Agency (EPA) recommends the use of solid-phase extraction (SPE). High-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) are the basis for standard PAH identification and determination. Ultraviolet (UV) absorption and room temperature fluorescence detection are both widely used in HPLC, but the specificity of these detectors is modest. Since PAH identification is solely based on retention times, unambiguous PAH identification requires complete chromatographic resolution of sample components. When HPLC is applied to “unfamiliar” samples, the EPA recommends that a supporting analytical technique such as GC-MS be applied to verify compound identification and to check peak-purity HPLC fractions. Independent of the volume of extracted water, the approximate time required to separate and determine the sixteen “priority pollutants” (EPA-PAH) via HPLC is approximately 60min. If additional GC-MS analysis is required for unambiguous PAH determination, the total analysis time will reach 2-3 hours per sample. If the concentrations of target species are found to lie outside the detector's response range, the sample must be diluted and the process repeated. These are important considerations when routine analysis of numerous samples is contemplated. Parent PAH are relatively inert and need metabolic activation to express their carcinogenicity. By virtue of the rich heterogeneous distribution of metabolic products they produce, PAH provide a full spectrum of the complexity associated with understanding the initial phase of carcinogenesis. PAH metabolites include a variety of products such as expoxides, hydroxyl aromatics, quinines, dihydrodiols, dioepoxides, tetrols and water soluble conjugates. During the past decades tremendous efforts have been made to develop bio-analytical techniques that possess the selectivity and sensitivity for the problem at hand. Depending on the complexity of the sample and the relative concentrations of the targeted metabolites, a combination of sample preparation techniques is often necessary to reach the limits of detection of the instrumental method of analysis. The numerous preparation steps open ample opportunity to metabolite loss and collection of inaccurate data. Separation of metabolites has been accomplished via HPLC, capillary electrophoresis (CE) and GC-MS. Unfortunately, the existence of chemically related metabolic products with virtually identical fragmentation patterns often challenges the specificity of these techniques. This dissertation presents significant improvements in various fronts. Its first original component – which we have named solid-phase nano-extraction (SPNE) - deals with the use of gold nanoparticles (Au NPs) as extracting material for PAH. The advantages of SPNE are demonstrated for the analysis of PAH in water samples via both HPLC1 and Laser-Excited Time-Resolved Shpol'skii Spectroscopy (LETRSS).2 The same concept is then extended to the analysis of monohydroxy-PAH in urine samples via SPE- HPLC3 and In-Capillary SPNE-CE.4 The second original component of this dissertation describes the application of Shpol'skii Spectroscopy to the analysis of polar PAH metabolites. The outstanding selectivity and sensitivity for the direct analysis of PAH at trace concentration levels has made Shpol'skii spectroscopy a leading technique in environmental analysis.5 Unfortunately, the requirement of a specific guest-host combination - typically a non-polar PAH dissolved in an n-alkane - has hindered its widespread application to the field of analytical chemistry. This dissertation takes the first steps in removing this limitation demonstrating its feasibility for the analysis of polar benzo[a]pyrene metabolites in alcohol matrixes.
Ph.D.
Doctorate
Chemistry
Sciences
Chemistry