Cardiovascular diseases (CVDs) remain to be the leading causes of morbidity and mortality in Hong Kong and worldwide. Among different modifiable risk factors, dietary pattern is on the major determinant for CVD and overall mortality. Other than pharmacological therapies for cardiovascular risk factors, such as hypertension, hyperlipidemia and diabetes, maintaining a healthy diet is a more sustainable method in general population to prevent CVDs. Current lifestyle intervention in the West countries focus on high intake of fruit and vegetables with more than 400g per day and limited saturated fats with less than 10% of energy, there is very limited data on impact of dietary pattern on CVDs in Chinese. Prior studies among Chinese in Hong Kong have shown that only half of the local population fell within these recommended ranges for fat, saturated fatty acid and cholesterol intakes. Several different dietary patterns have been recommended for CVDs prevention based on: i) food groups, such as Mediterranean diet, the Dietary Approaches to Stop Hypertension (DASH) diet; ii) macronutrients: the low-carbohydrate diet, low glycemic index diet, very-low- fat diet and iii) nutrition or vitamin supplement. However, the effect of different dietary patterns based on modulations of food group, macronutrients and particular micronutrients on vascular structure and function in Chinese subjects is unclear. In the first part of this thesis, the relationships between different dietary pattern and surrogate markers of subclinical atherosclerosis and vascular function in different high risk populations for CVDs were investigated. In Chapter 3, we compared the assessment of dietary pattern in Chinese using different tool, including Food Frequency Questionnaire (FFQ); Dietary Record; and Dietitian assessment. In this study, we demonstrated that suitable dietary assessments tools should be chosen for the assessment of different dietary pattern, according to characteristics of assessments. In Chapter 4, the relationship between the fruit intake and subclinical atherosclerosis as measured by carotid intimal thickness (IMT) was investigated in patient with type II diabetes mellitus (DM). Our results showed that high fruit intake was associated with lower burden of carotid atherosclerosis, independent of level of vitamin intake in patients with type II DM. In Chapter 5, we compared the impact of high carbohydrate diet on arterial stiffness between control subjects without CVDs and patients with high risk for CVDs. Our findings showed that high carbohydrate diet mainly affected patients with established CVDs, and their increased arterial stiffness was associated with an elevation of blood pressure. In Chapter 6, we determined the effect of dietary vitamin intake on oxidative stress in patients with high risk of CVDs. In those high risk patients for CVDs, we demonstrated that increased dietary intake of vitamin A, beta-carotene and alpha tocopherol were associated with decreased oxidative stress, but these relationships were not observed in those control subjects without CVDs. It is likely attributed to the higher systemic oxidative stress levels in patients with high risk of CVDs. On the other hand, food intake may also affect the clinical efficacy of cardiovascular therapies. In particularly, it has been well established that herbal intake which is commonly used by Chinese can affect the anticoagulant effect of warfarin on patients with non-valvular atrial fibrillation (AF). Thus, in this second part of the thesis, we investigated the effect of concomitant herbal intake on anticoagulation control in patients with non-valvular AF treated with warfarin. Our results showed that patients with AF treated with warfarin had limited knowledge on potential interaction between herbal substances in foods and warfarin, in which increased herbal substances intake significantly reduced the percentage time of anticoagulant effect within the therapeutic range. Moreover, a single section of education on knowledge of herbal ingredients did not improve their percentage time of therapeutic range for these patients. In conclusion, these findings suggest that dietary pattern in Chinese might have significant impact of vascular function in patients with type II DM and high risk for CVDs. Moreover, the herbal substances in the diet among Chinese could have significant impact of the therapeutic effects in some of the cardiovascular medications, such as warfarin. Future clinical studies will be needed to confirm these potential beneficial effects of particular diet intake on vascular function in patients with high risks of CVDs as well as potential interaction between herbal substances in Chinese diet and cardiovascular medications. / published_or_final_version / Medicine / Doctoral / Doctor of Philosophy

The independent effect of a high polyunsaturated:saturated fat (P:S) diet on glycemic control in humans has been poorly studied. We propose that a P:S $>$ 1.0 vs P:S 1.0 vs. P:S 1.0. HDL and IGFl were significantly lower with the P:S $>$ 1.0. Si was unaffected by the P:S difference, however, trends towards decreased Sg and increased insulin secretion were seen with P:S $>$ 1.0. The small sample size limits the making of firm conclusions, however, it suggests that glycemic control may be improved through increased insulin secretion a result of an increase in P:S.

The nutritional status of 78 women was assessed during the third trimester of pregnancy. The study was conducted in military barracks in Sierra Leone with 39 adolescent women (<20 years) and 39 adult women (>20 years).Twenty-four hour dietary recall interviews and anthropometric measures were collected. Laboratory, clinical and physiological data were obtained from the subjects' medical records. The dietary analysis of the diets consumed by adolescent and adult women showed differences in the intakes of only calcium, phosphorous, potassium, selenium and sodium. The average diet consumed by the women was <2/3 the recommended guidelines for carbohydrate and <2/3 the Recommended Dietary Allowances for persons in the U.S. for kilocalories, protein, riboflavin, pyridoxine, folacin, pantothenic acid, cholesterol, calcium, iron, magnesium, phosphorous, sodium and zinc. The women consumed diets that were >100 percent of the RDA for vitamins A, C, E, niacin and selenium. Differences occurred in the infant birthweights and Apgar scores at 1, 5 and 10 minutes between women who had abnormal measures for hemoglobin, hematocrit, ketonuria, albuminuria, glycosuria and/or malaria parasites and the women who were healthy.Maternal weight gain, age and infant health status did not correlate. The average weight gain for all the women was 17.85 kg which is within the acceptable range recommended for pregnancy. Maternal weight-at-term, gestational age, triceps skinfolds, arm circumference, hemoglobin, hematocrit were correlated with infant birthweight, length and head circumference. Maternal hemoglobin and hematocrit further correlated with infant Apgar scores at 1, 5 and 10 minutes.Hemoglobin and hematocrit levels were very low for the average women in the study (X 9.7 g/dl and 29.7 percent respectively). The malaria reduced the infant birthweight by 431 g. Albuminuria and ketonuria were associated with reduced infant birthweight while modest glycosuria was associated with increased birthweight. / Department of Home Economics

The status of vitamin B-6 (B6) nutriture of nine persons (4F;5M) with insulin dependent diabetes mellitus (IDDM), nine persons (5F;4M) with non-insulin dependent diabetes mellitus (NIDDM), and 18 control individuals (9F;9M) was evaluated, using biochemical and dietary indicators of B6 status. The biochemical indices employed were plasma concentration of pyridoxal 5'-phosphate (PLP), urinary 4-pyridoxic acid (4PA) excretion, and urinary kynurenic acid (KA) and xanthurenic, acid (XA) excretion following a tryptophan load test (2 g L-tryptophan oral load). Dietary B6 intake and the ratio of B6 (mg) to dietary protein (g) (B6:protein) were determined. Fasting blood, two consecutive 24 h urine collections and three consecutive daily weighed diet records were obtained on each of two occasions, separated by 30-70 d. Diet records were analyzed for vitamin B-6 and protein intake using nutrient data bases. Samples of 70 foods, for which the data bases lacked B6 values, were obtained and analyzed for total B6 content by a microbiological method. The plasma concentration of PLP was determined by an enzymatic method, and plasma alkaline phosphatase activity by a colorimetric method. Urinary 4PA was separated by HPLC, urinary KA and XA by ion exchange, and each metabolite was determined fluorometrically. The mean daily vitamin B-6 intake of each group exceeded the recommended dietary allowance (RDA). The mean B6:protein ratios ± standard deviations (SD) for the groups of females were 0.0200±0.0027, 0.0304±0.0101, and 0.0254±0.0099 for IDDM, NIDDM and control (C), respectively. The respective B6:protein ratios for the males were 0.0280±0.0040, 0.0242±0.0038 and 0.0241±0.0078. The mean±SD plasma PLP concentrations for females were 22.4±6.8, 21.8±9.6 and 37.4126.8 nmol/L for IDDM, NIDDM and C, respectively. The mean plasma PLP concentrations of the two groups of females with diabetes were at the low end of a range (22.4-25.3 nmol/L) suggested to indicate marginal status, and 56% of the females with diabetes had PLP concentrations below the lower boundary of the marginal range. For the three groups of males the PLP concentrations were in the same rank order as dietary B6 intake; 53.9±18.2, 43.6±7.2 and 37.5±17.7 nmol/L for IDDM, NIDDM and C, respectively. Plasma PLP concentration was strongly and significantly correlated with B6 intake in both diabetes (n=18, r=.744, p<.001) and C (n=18, r=.695, p<.001) groups, but was also negatively associated with plasma AP activity only for the diabetes group (n=18, r=- .454, a=.058). The mean plasma AP activity of females with NIDDM was significantly higher than that of the female C group (p<.01). Greater than normal AP hydrolysis of PLP is thought to have contributed to the low plasma PLP concentrations observed in the females with NIDDM. Levels of urinary 4PA excretion by females were 8.76±2.10, 7.61±12.57 and 8.15±14.43 μmol/d for IDDM, NIDDM and C, respectively, or 87, 63 and 72% of B6 intake. For males the urinary 4PA levels were 12.76±14.53, 10.32±11.77 and 9.81+3.34 μmol/d, respectively, or 76, 68 and 78% of B6 intake. All subjects excreted 4-PA in amounts indicative of adequate B6 status. All means for tryptophan metabolites were within ranges seen for normal subjects, both pre and post-tryptophan load. None of the subjects with diabetes and only one female C subject excreted more than 65 μmol XA in 24 h after the tryptophan load (upper boundary of normal response to 2 g tryptophan load). Mean post-load excretion of XA and KA of diabetes groups was numerically lower than that of same sex controls in all comparisons, although in only one instance was the difference significant (NIDDM females post-load KA, p<.05). The results of the tryptophan load test suggest adequate B6 function in the kynurenine pathway those with diabetes and controls. Individuals with diabetes were found to consume adequate or above amounts of B6 by the standard of the RDA. Low plasma PLP levels were observed in females with IDDM who had the lowest B6 intake, and in females with NIDDM who had the highest plasma AP activity. The present research indicates that low PLP may be present in diabetes, as observed by other investigators, despite seemingly adequate B6 nutriture. However, normal to above normal amounts of urinary 4-PA excretion indicated adequate body stores of B6, and normal response to the tryptophan load test suggested adequate function of B6 in the liver of persons with diabetes. Plasma PLP concentration alone may not be an adequate B6 status indicator in persons with diabetes. Based upon the levels of multiple indicators, the vitamin B-6 status of those persons with diabetes studied was judged to be adequate. / Graduation date: 1991

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No description available.

To investigate the possibility that malnutrition is an important factor that prolongs respiratory failure (PRF), I studied the effects of pharmacologic injections of recombinant human growth hormone (rhGH), an important anabolic stimulus, on nutritional and respiratory parameters in patients requiring mechanical ventilation for more than three days. Patients were excluded from consideration if dominating factors known to prolong ventilatory failure had not been stabilized. Over ten months, 106 patients in PRF were evaluated, but only six met the selection criteria. Three patients were randomized to receive standard nutritional support, and three into a group that received the equivalent nutrition plus 5 mg/day of rhGH for 14 days or until withdrawal of mechanical ventilation. Baseline characteristics of the selected patients were divergent as demonstrated by body mass indexes ranging from 14 to 42 (kg/m$ sp2),$ baseline maximal inspiratory pressures (PI$ sb{ max}$ from $-$15 to $-$70 cm H$ sb2$O, and Day 1 N balances from $-$13.5 to 1.2 g N/day. Despite increased plasma insulin-like growth factor-1 concentrations, the mean daily N balances of the rhGH-treated group were no better than the controls (1.3 $ pm$ 5.0 vs. 0.4 $ pm$ 2.6 g N/day; Mean $ pm$ SD), nor were there differences in PI$ sb{ max},$ level of ventilatory assistance required, and days to weaning. The persistence of respiratory failure in the overwhelming majority of patients in PRF appears to be due to factors already known to prevent weaning from mechanical ventilation. Even the carefully selected patients enrolled in the present study were insufficiently homogeneous or stable enough to allow proper testing of the experimental hypothesis.

No description available.

The nutritional value of indigenous fodder plants has been reported to be high and constant throughout seasons as compared to grasses. The aim of this study was to evaluate the nutritional value of three tree species of the Combretum family, C. apiculatum, C. molle, C. zeyheri, and two other plant species, Colophospermum mopane and Pelthophorum africanum. This would be achieved through the determination of chemical composition (ash, dry matter (DM), organic matter (OM), CP, acid detergent fibre (ADF), acid detergent lignin (ADL), acid detergent indigestible nitrogen (ADIN), condensed tannins (CT) and ether extract (EE)), rumen degradability and in vitro digestibility of the leaves of these species were determined. The foliage of the tree species were collected in and north of Pretoria. After rinsing a portion of each species' samples, they were freeze-dried, prepared for analyses and stored as fresh samples pending analyses. The in situ analysis was done as blanket analysis over all the seasonal samples of each plant species excluding Mopane. This was done because the leaf materials collected were not enough to conduct a complete trial for each seasonal collection. Therefore sites were not considered for statistical analyses hence species were compared across seasons only. All the plant species exhibited a wider range of the chemical fractions. Their ash concentrations ranged from 30.3 g/kg DM for C. zeyheri to 85.8 g/kg DM forC. molle, NDF 270.3 g/kg DM for C. apiculatum to 410.1 g/kg DM for P africanum, ADF 208.1 g/kg DM P. africanum to 375.2 g/kg DM for C. molle. Their CP ranged from 62.9 g/kg DM for C. molle to 172 g/kg DM for Mopane, CT 65.6 mg sorghum tannin equivalent (STE)/g DM for C. zeyheri to 660.3 mg STE/g DM for Mopane, ADIN ranged from 1.2 g/kg DM for C. apiculatum to 3.3 g/kg DM in C. mopane. The range of some mineral concentrations of all the plants was not as wide as the other fractions. The concentrations of Ca ranged from 7.9 g/kg DM for Mopane to 16 g/kg DM for C. molle, K 1.2 g/kg DM Mopane to 7.8 g/kg DM for C. molle, Mg 1.4 g/kg DM for C. molle to 3.8 g/kg DM for C. apiculatum. The concentrations of Cu ranged from 7.8 mg/kg DM for C. molle to 66 mg/kg DM for C apiculatum, Fe 169 mg/kg DM for Mopane to 435 mg/kg DM for C. zeyheri. The in vitro dry matter digestibility (IVDOM) ranged from 52.6% for Mopane and C. zeyheri to 64.1% for C. apiculatum. The in situ degradability fractions for the Combretum species ranged as follows: soluble fraction was 4.02% for C. apiculatum to 25.4% for C. zeyheri; degradable fraction was 34% for C. zeyheri to 44% for C. apiculatum and the extent of nitrogen (N) degradation was 47% for C. apiculatum to 60% for C. zeyheri. The concentrations of the chemical fractions of all the plants did not show a particular seasonal trend. However significant and insignificant variations were observed. The CP concentrations were almost constant implying a better N supply to animals throughout the seasons. The CT concentrations were not high enough to adversely affect the digestibility of protein. The Combretum species showed reasonable N degradability in situ, C. zeyheri the most degradable. The plant's digestibility values were within the range of browse plants. These results cannot be conclusive on the eventual nutritional value of these plants to the animals. Further studies would be necessary to quantify the availability of the chemical fractions and the foliage's palatability to the animals. / Dissertation (M Inst. Agrar (Animal Production))--University of Pretoria, 2005. / Animal and Wildlife Sciences / unrestricted

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