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The reactions of the early and intermediate stages of protein glycation were studied using bovine serum albumin and hen egg white lysozyme as model proteins, and D-glucose and D-fructose as model reducing sugars. The reactions were studied under low moisture and limiting sugar conditions in the presence and absence of oxygen in a closed system. Several analytical methods, including the fluorescamine assay, total Maillard fluorescence and solubility measurement, size exclusion chromatography, and electrospray ionization mass spectrometry were used to follow the glycation reaction. The effect of glycation on the structure of proteins was also studied by electrospray ionization mass spectrometric peptide mapping. The results showed that under low moisture conditions, the initial rate of glucation was 5 to 6 times higher than the initial rate of fructation, both in the presence and in the absence of oxygen. The presence of oxygen in the reaction system induced selectivity of the glycation of the protein amino groups during the initial stages of the reaction, due to competition between glycation and glycoxidation. The reaction, however, occurred at a higher rate in the presence of oxygen than in its absence, especially during the latter stages of the reaction. The more reactive glycoxidation products, formed during the initial stages of the reaction also participated in the glycation reaction and increased the involvement of arginine residues in the glycation reaction. The glycation reaction also resulted in a heterogeneous mixture of protein glycoforms with varying degrees and extent of glycation. The heterogeneity of the glycated species was further complicated by the involvement of glycoxidation products in the glycation reaction, resulting in a distribution of different classes of glycoconjugates. Limited glycation improved protein solubility and increased solvent accessibility into the interior of the protein, thereby, increasing protein digestibility. Electrospr

Background: Serum estradiol levels decline after menopause and the effect on mental health-related quality of life (MHR-QOL) is unclear. Objective: To determine if there is an association between endogenous serum estradiol levels and MHR-QOL in healthy postmenopausal women. Methods: This cross-sectional study used baseline Canadian data from the Mammary Prevention.3 trial. Serum estradiol was measured with liquid chromatography-tandem mass spectrometry. Outcomes for MHR-QOL were the Medical Outcomes 36-Item Short Form Health Survey (SF-36) Mental Health Inventory-5 (MHI-5), Mental Component Summary (MCS), and the Menopause-Specific Quality of Life Questionnaire (MENQOL)-psychosocial domain. Results: There were no statistically significant associations between estradiol levels and MHR-QOL in univariate analyses (n=455). Multivariable linear regression predicted statistically significant differences in MCS (R2=0.10, P=0.03) and MENQOL-psychosocial domain (R2=0.10, P=0.04), however estradiol was not a significant predictor. Conclusions: This study did not find a statistically significant association between endogenous serum estradiol levels and MHR-QOL in healthy postmenopausal women.

Cardiovascular disease is now the leading cause of death worldwide. Serum amyloid A (SAA), a positive acute phase reactant, along with C-reactive protein is used clinically as a marker of cardiovascular disease risk. However, recent data has shed light on a possible causal role of SAA in the development of atherosclerosis, the most pervasive form of cardiovascular disease. Several inflammatory diseases such as diabetes and obesity are known to confer increased risk of developing cardiovascular disease. Individuals with these diseases all have modest but persistent elevation of SAA. To determine if SAA caused the development of atherosclerosis, apoe-/-chow fed mice were injected with either an adenoviral vector expressing human SAA1 (ad-hSAA1), a null adenoviral vector (ad-Null) or saline. Human SAA levels rapidly increased, albeit briefly then returned to baseline within 14 days in mice that received ad-hSAA1. After 16 weeks, mice that received ad-hSAA1 had significantly increased atherosclerosis compared to controls on the aortic intimal surface (p<0.0001), aortic sinus (p<0.05) and the brachiocephalic artery (p<0.05). According to the “response to retention” hypothesis; lipoprotein retention by vascular wall proteoglycans is a key initiating event in the development of atherosclerosis. We previously reported that SAA-stimulated vascular smooth muscle cells expressed biglycan with increased glycosaminoglycan chain length and increased binding affinity for low density lipoprotein. To further test the role of biglycan on the development of atherosclerosis we generated biglycan transgenic mice. These mice were crossed to the ldlr-/- mouse on a C57BL/6 background and fed a pro-atherogenic western diet for 12 weeks. There was a significant increase in atherosclerotic lesion area on the aortic intimal surface (p<0.05) and the aortic sinus (p<0.006), as well as a significant correlation between vascular biglycan content and aortic sinus atherosclerotic lesion area (p<0.0001). These data demonstrate that transiently increased SAA resulted in increased atherosclerosis compared to control mice, possibly via increased vascular biglycan content. In support of this we found that biglycan transgenic mice had significantly increased atherosclerosis compared to wildtype controls, likely through increased lipid retention in the vascular wall.

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OBJECTIVE: The main aim of this thesis was to investigate the role of nutrition during "early" HIV-infection in African women. METHODS: Data reported in this investigation formed part of two cross-sectional studies, the THUSA and Mangaung studies. The Mangaung study investigated women and, therefore, the sub-sample of the THUSA study was chosen accordingly. The data of the two studies were kept and analysed separately. The investigation consisted of 1040 women from the THUSA study, aged between 15 and 90 years of which 120 (11.5%) were HIV infected. The Mangaung study comprised of 488 women aged between 25 and 44 years of which 248 (51%) women were infected. Demographic data, anthropometric measurements, health outcome variables and habitual nutrient intakes by a quantified food frequency questionnaire were used. The SPSS statistical package (version 14.0; SPSS Inc., Chicago, Illinois, 2005) was used to analyse data. Descriptive statistics were done expressing variables as means, medians, standard deviations (SD), standard errors (SE) and confidence intervals (CI). An analysis of variance (ANOVA) was done to test for significance between the HIV-infected and non-infected groups in both studies. Partial correlations were done in the infected and non-infected groups to determine associations between dietary / nutrient intake, anthropometry and the biological health variables. In the THUSA study we controlled for age, education level, degree of urbanization and alcohol intake and in the Mangaung study for age, education level and alcohol intake. Nutrient intakes of both infected and non-infected women above and below median values as well as in the first and fourth quartile of total cholesterol (TC) and albumin distribution were compared to assess the role of nutrients in the observed decreases in TC and albumin of HIV-infected women. RESULTS AND DISCUSSION: The dietary intakes of the HIV-infected women in both the studies did not differ significantly from the non-infected women. Total serum cholesterol, albumin, fibrinogen and blood pressure were significantly lower in the HIV-infected women in both the THUSA and Mangaung studies. The non-infected THUSA women with lower serum cholesterol levels (than the median) had significantly lower intakes of percentage energy from fat (25.2 versus 26.4%, p ≤0.027), percentage energy from total protein (11.6 versus 12.1%, p≤0.000), animal protein (25.6 versus 27.7g, p≤0.005), and significantly higher intakes of plant protein (32.2 versus 29.4g, p≤0.002) and fibre (16.9 versus 15.89 p≤0.029). There were no significant differences observed in the nutrient intakes in the infected women with serum cholesterol levels above and below the median. In the Mangaung study no significant nutrient intake differences were observed in both of the HIV-infected and non-infected women with lower and higher than the median TC levels. In the THUSA study, higher intakes of fat (percentage energy) were close to significant (27.3 versus 24.5%, p≤0.053) in the infected women with higher (than the median) albumin levels. In the non-infected group with higher albumin levels, significant differences were observed in percentage energy from fat (26.6 versus 24.9%; p≤0.001) protein (12.2 versus 11.6%; p≤0.001) and carbohydrate (62.8 versus 65.2%; p≤0.000). Higher intakes of saturated fat (SATFAT) (17.7 versus 16.1g, p≤0.008), monounsaturated fats (MUFAT) (19.3 versus 17.4g, p≤0.004) as well as higher intakes of animal protein (28.5 versus 24.4g, p≤0.000) were observed in the group with higher than the median levels of serum albumin. In the Mangaung study the HIV-infected women (with higher than the median serum albumin levels), had significantly higher intakes of energy (13 275 versus 11 622 kJ, p≤0.022), polyunsaturated fatty acids (32.3 versus 17.3g, p≤0.036), dietary cholesterol (412.9 versus 344.5mg, p≤0.043) and plant protein (42.3 versus 35.3g, p≤0.008). No differences were observed in the non-infected women. The further analyses, comparing the dietary intakes in both studies of infected and non-infected women with TC and albumin levels in the first and fourth quartiles, showed that in the THUSA study, non-infected women with lower TC levels had significantly lower intakes of protein (% of total energy), total fat (% of total energy) and vitamin B12 and significantly higher intakes of total energy (TE), plant protein, total carbohydrate, % TE from carbohydrate, dietary fibre, added sugar and thiamine. In the infected women saturated fatty acids (SATFAT), calcium and the fat ratio (polyunsaturated/saturated ratio) differed significantly between women with TC levels in the first and the fourth quartile. A significant higher intake of riboflavin was seen in the non-infected women from Mangaung with TC levels in the fourth quartile, while significant higher intakes of energy, total protein, animal protein, total fat, SATFAT, MUFAT, total carbohydrate, phosphorus, chromium and iodine was seen in the infected women with TC levels in the fourth quartile. These results suggest that a more "westernized" diet with higher intakes of energy, and animal derived foods (SATFAT and calcium) could have protected against the detrimental decreases in TC observed in HIV infection. Significant differences were observed in the intakes in the non-infected THUSA women who had serum albumin in the first and fourth quartiles. lntakes in percentage energy from protein and fat, animal protein, total fat, SATFAT, MUFAT, calcium, zinc, vitamin C and fat ratio, were significantly lower in the women with albumin levels in the first quartile. Significantly higher carbohydrate intakes were observed in the women who had serum albumin levels in the first quartile. In the Mangaung study, significant differences were seen in the intakes between infected women who had serum albumin levels in the first and fourth quartiles. lntakes of total energy, protein, fat, MUFAT, SATFAT, carbohydrate, magnesium, zinc, chromium, biotin, pantothenic acid and iodine were significantly lower in the infected women with serum albumin levels in the first quartile. In the non-infected women significantly lower intakes of calcium were observed in the group who had serum albumin levels in the first quartile compared to those who had serum albumin levels in the fourth quartile. These results also suggest that a more "westernized” diet was associated with higher albumin levels in HIV-infected women. CONCLUSION: It is well known that nutrition has an integral part to play in the care of people living with HIV/AIDS (PLWHA). Maintaining proper nutrition, weight and immune function is thought to delay disease progression, prolong the asymptomatic phase and improve survival. These analyses suggest that the "prudent" diet generally regarded as an optimal diet for prevention of non-communicable diseases, may not be the optimal diet for PLWHA. The overall analyses therefore suggest that a more "westernized" diet, higher in fat and protein could be more beneficial to asymptomatic HIV-infected women compared to that of a more "prudent" diet. As these studies were not primarily designed to investigate HIV and nutrition, the role of a higher energy, fat and animal protein intake ("western" diet) in asymptomatic HIV warrants urgent investigation. / Thesis (Ph.D. (Nutrition))--North-West University, Potchefstroom Campus, 2007.

Small intestinal neuroendocrine tumours (SI-NETs) are rare, hormone producing and proliferate slowly. Patients usually display metastases at time of diagnosis, the tumours are difficult to cure, and the disease course is unpredictable. The gene expression pattern was investigated in paper I, with emphasis on aggressive disease and tumour progression. Expression microarrays were performed on 42 tumours. Unsupervised hierarchal clustering revealed three clusters that were correlated to clinical features, and expression changes from primary tumour to metastasis. Eight novel genes, ACTG2, GREM2, REG3A, TUSC2, RUNX1, TGFBR2, TPH1 and CDH6 may be of importance for tumour progression. In paper II, expression of ACTG2 was detected in a fraction of SI-NETs, but not in normal enterochromaffin cells. Inhibition of histone methyltransferase and transfection of miR-145 induced expression and no effect was seen after DNA methylation or selective EZH2 inhibition in vitro. miR-145 expression was reduced in metastases compared to primary tumours. Overexpression of ACTG2 inhibited cell growth, and inducing ACTG2 may have therapeutic effects. TCEB3C (Elongin A3) is located on chromosome 18 and is imprinted in some tissues. In paper III a reduced protein expression was detected. The gene was epigenetically repressed by both DNA and histone methylation in a tumour tissue specific context. The expression was also induced in primary cell cultures after DNA demethylation and pyrosequencing revealed promoter region hypermethylation. Overexpression of TCEB3C inhibited cell growth by 50%, suggesting TCEB3C to be a tumour suppressor gene. In paper IV, 69 biomarkers were analysed in blood serum using multiplex proximity ligation assay. Nineteen markers displayed different levels between patients and controls. In an extended cohort, ELISA analysis showed elevated serum levels of Mindin, DcR3 and TFF3 in patients and protein expression in tumour cells. High levels of DcR3 and TFF3 were associated with poor survival, and DcR3 may be a marker for liver metastases. Mindin, DcR3, and TFF3 are potential novel diagnostic biomarkers for SI-NETs.

No description available.

Background: Serum estradiol levels decline after menopause and the effect on mental health-related quality of life (MHR-QOL) is unclear. Objective: To determine if there is an association between endogenous serum estradiol levels and MHR-QOL in healthy postmenopausal women. Methods: This cross-sectional study used baseline Canadian data from the Mammary Prevention.3 trial. Serum estradiol was measured with liquid chromatography-tandem mass spectrometry. Outcomes for MHR-QOL were the Medical Outcomes 36-Item Short Form Health Survey (SF-36) Mental Health Inventory-5 (MHI-5), Mental Component Summary (MCS), and the Menopause-Specific Quality of Life Questionnaire (MENQOL)-psychosocial domain. Results: There were no statistically significant associations between estradiol levels and MHR-QOL in univariate analyses (n=455). Multivariable linear regression predicted statistically significant differences in MCS (R2=0.10, P=0.03) and MENQOL-psychosocial domain (R2=0.10, P=0.04), however estradiol was not a significant predictor. Conclusions: This study did not find a statistically significant association between endogenous serum estradiol levels and MHR-QOL in healthy postmenopausal women.

Alpha1-proteinase inhibitor (alpha1-PI) has been shown to be a useful marker of gastrointestinal protein loss in some species. The objectives of this study were, first, to develop and analytically validate an ELISA for the measurement of alpha1-PI in feces and serum from cats, and, second, to evaluate fecal alpha1-PI concentrations in healthy cats and cats with chronic gastrointestinal disease. The lower detection limits of the ELISA were 0.02 g/L for serum and 0.04 microgram/gram for feces. The observed-to-expected (O/E) ratios for serial dilutions of serum and fecal samples ranged from 100.0 to 129.7% (mean +/- SD: 112.2 +/- 9.9%) and 103.5 to 141.6% (115.6 +/- 12.8%), respectively. The O/E ratios for samples spiked with seven known concentrations of alpha1-PI ranged from 82.3 to 107.8% (94.7 +/- 7.6%) for serum and 78.5 to 148.7% (96.8 +/- 18.2%) for feces. The coefficients of variation for intra-assay and inter-assay variability were <7.9% and &lt;12.1% for serum, and 5.3%, 11.8%, and 14.2% and 7.7%, 10.2%, and 20.4% for feces, respectively. Reference intervals were 0.6 to 1.4 g/L for serum and up to 1.6 microgram/g for feces. We conclude that this ELISA is sufficiently linear, accurate, precise, and reproducible. For the clinical evaluation, twenty cats with clinical signs of chronic gastrointestinal disease and 20 healthy control cats were enrolled. The diseased cats were grouped into two groups: mild to moderate idiopathic inflammatory bowel disease (IBD) (Group A; n=8) and severe IBD or neoplastic disease (Group B; n=12), based on histopathology results of endoscopic biopsies. Fecal alpha1-PI concentrations and serum concentrations of total protein, albumin, globulin, cobalamin, folate, pancreatic lipase immunoreactivity, and trypsin-like immunoreactivity were determined. Nineteen of the 20 diseased cats had increased fecal alpha1-PI concentrations, ranging from 1.9 to 233.6 microgram/g (normal range: <= 1.6 microgram/g). Fecal alpha1-PI concentrations were statistically significantly different between healthy cats and cats of Group A (median: 3.9 microgram/g, range: 1.3 to 9.2 microgram/g, P<0.001) or cats of Group B (median: 20.6 microgram/g, 4.3 to 233.6 microgram/g; P<0.001), and also between cats of Groups A and B (P<0.01). Hypoalbuminemia, hypoproteinemia, and hypocobalaminemia were detected in 88%, 83%, and 56% of the diseased cats, respectively. Our study suggests that increased fecal alpha1-PI concentrations in association with hypoalbuminemia may be a common finding in cats with IBD or GI neoplasia. Furthermore, alpha1-PI concentrations appear to be higher in cats with severe IBD or confirmed GI neoplasia when compared to cats with mild to moderate IBD.