Dissertationen zum Thema „Coronary heart disease Molecular aspects“

Amendments inserted at back. "May 2002" Includes bibliographical references (leaves 237-290) Experiments described in this thesis address the potential role of inducible nitric oxide synthase (iNOS) in hibernating myocardium. Specifically it was sought to establish a cellular model of hibernating myocardium and investigate the expression, regulation and effects of iNOS in this model. Experiments were performed using primary cultures of neonatal rat ventricular myocytes.

Thesis (MSc)--Stellenbosch University, 2000.
ENGLISH ABSTRACT: Progressive familial heart block type I (PFHBI) is a cardiac ventricular conduction disorder of unknown cause associated with risk of sudden death, which has been described in several South African families. Clinically, PFHBI is characterised by right bundle branch block on ECG, which may progress to complete heart block, necessitating pacemaker implantation. The disease shows an autosomal dominant pattern of inheritance with evidence of genetic anticipation. Using genetic linkage analysis, the PFHBI-causative gene was mapped to a 10 eentimorgan (cM) gene-rich area of chromosome (C) 19q13.3, which has, subsequently, been reduced to 7cM by fine mapping with polymorphic dinucleotide (CA)n short tandem repeat (STR) markers. Several attractive candidate genes, including muscle glycogen synthase (GSY 1) and histidine-rich calcium binding protein (HRC), lie within this region. The aim of the present study was two-fold: 1) to identify and characterise tetranucleotide (AAAT)n STRs within the PFHBI critical region that could be developed as polymorphic markers for use in genetic fine mapping and 2) to screen selected regions of GSY 1and HRC, positional candidate genes, for the presence ofPFHBI-causing mutation(s). Cosmids harbouring CI9q13.3 insert DNA were screened for the presence of (AAAT)n STRs by dot blot and Southern blot hybridisation using a radiolabelled (AAAT)lO oligonucleotide probe. To characterise the harboured (AAAT)n STRs, the positively hybridising fragments identified by Southern blot were sub-cloned, sequenced and primers designed from the unique repeat-flanking sequences. These primers were used to genotype the (AAAT)n repeat locus to assess its polymorphic nature in a panel of unrelated individuals. Alternatively, vectorette PCR, a rapid method of identifying repeat sequences and obtaining the flanking sequences in large inserts, was employed to develop polymorphic markers from the positively hybridising clones. Selected exons of GSY1 and HRC were screened for the presence of potentially disease-causing mutations by PCR-SSCP analysis and direct sequencing, respectively, in PFHBI-affected and unaffected family members. Of the available cosmid clones that gave strong signals on dot blot and Southern blot hybridisation, three, 29395, 24493 and 20381, were located within the critical PFHBI area and were used for marker development. An interrupted (AAAT)n repeat motif (n less than 5) was identified in cosmid 29395, however, the repeat locus was not polymorphic in the tested population. No (AAAT)n motif, single or repeated was observed in the partial sequence of the sub-cloned fragment of cosmid 24493. Using vectorette peR, no repeated (AAAT)n motif was identified on sequencing the generated products in either cosmid 24493 or 2038l. However, diffuse single AAAT motifs were detected in both cosmids. Exons 4, 5, 11, 12 and 16 of GSY 1, containing domains that are conserved across species, and the conserved eterminus- encoding exons 2-6 of HRC were selected for screening for potential PFHBI-causing mutation(s). However, no sequence variations were detected. The interrupted (AAAT)n repeat identified in cosmid 29395 was not polymorphic, which confirmed reports that complex repeats, especially those containing AAAT motifs of less than 6 repeats, are not polymorphic. One possible explanation for the absence of a repeated AAAT motif in cosmids 24493 and 20381, which both gave positive hybridisation signals, is that the low annealing temperature of the AfT -rich repeat-anchored primers used in vectorette peR may have resulted in transient annealing to the diffuse single AAAT motifs detected on sequencing. The screened regions of candidate genes GSYI and HRC were excluded from carrying the disease-causing mutation(s). The availability of new sequence data generated by the Human Genome Project will influence future strategies to identify the PFHBI gene. Electronic searches will allow identification of STR sequences for development of polymorphic markers and gene annotation will allow selection of new candidate genes for mutation screening.
AFRIKAANSE OPSOMMING: Sien volteks vir opsomming

Coronary Heart Disease (CHD) is a major cause of death in Western countries. Mediterranean and Asian populations have a lower risk of death from CHD compared to Westernised population, as do vegetarian versus omnivorous populations. Dietary constituents of traditional diets consumed by these populations are thought to influence both the classical risk factors for CHD, and the more recently identified risk factors, such as oxidative modification of low density lipoprotein (LDL), LDL particle size, arterial compliance and haemostatic factors. The aim of this thesis was to examine the effects of several food components, particularly soybean and monounsaturated fat (MUFA), on CHD risk factors through 3 carefully controlled dietary interventions, and a cross-sectional study. A randomised crossover dietary intervention study was conducted in 42 healthy males to investigate the effect on CHD risk factors of replacing lean meat with tofu, a soybean product regularly consumed by Asian populations, while controlling all other dietary factors. The tofu diet resulted in significantly lower total cholesterol and triacylglycerol levels compared to the lean meat diet, and LDL particles that were more resistant to in vitro oxidative modification. However, insulin, fibrinogen, factor VII, and lipoprotein (a) were not significantly different on the 2 diets. A postprandial study was subsequently conducted to investigate any acute effects of a tofu test meal on the oxidative modification of LDL in 16 male subjects. There was no significant difference between the susceptibility of LDL to oxidative modification before and after the tofu meal. Twenty eight healthy subjects completed a separate randomised crossover dietary intervention comparing a high MUFA fat diet, using an Australian high oleic sunflower oil, with a low fat, high carbohydrate diet on CHD risk factors. The high MUFA oil diet significantly increased high density lipoprotein cholesterol compared to the low fat diet as well as producing LDL that were more resistant to oxidative modification. Neither the size of the LDL particle nor arterial compliance were significantly different on the 2 diets. Twelve matched pairs of vegetations and omnivores were also studies to compare the habitual diet of a low and higher risk population group, to compare their risk factors and identify dietary constituents that may explain the differences. The vegetarians consumed less saturated fat (SFA) and dietary cholesterol while consuming more polyunsaturated fat, dietary fibre and vitamin E compared to omnivores. The vegetarians had lower total cholesterol, LDL cholesterol and triacylglycerol levels compared to the omnivores and had LDL particles that were more resistant to in vitro oxidation. These findings contribute to our knowledge about the dietary constituents that can alter some CHD risk factors in healthy subjects, and which could reduce the risk of developing CHD. Investigations in high risk groups might reveal even more benefits.

The aim of this research was to identify psychological factors associated with outcomes of coronary heart disease (CHD) among patients in Malaysia. The research tested whether a model of psychological factors found to predict recovery from CHD in the West would be applicable in a collectivistic society such as Malaysia. Among the research questions posed were whether self-referent beliefs, coping styles and locus of control constructs would predict affective status for patients at the time of hospitalisation, and whether these psychological constructs would predict patients' affective status, functional status and quality of life up to nine months posthospitalisation. The research also looked at whether behavioural intentions assessed at the time of hospitalisation predict attendance at cardiac rehabilitation programmes (CRP) and the use of complementary medicine after hospital discharge. A series of studies were conducted to answer the research questions formulated based on the model developed for each study. Study 1 assessed the reliability and validity of measures developed in the West when used on a healthy Malaysian sample (N = 97). Study 2 examined the concurrent relationships among psychological variables assessed at the time of hospitalisation for 97 cardiac patients. Study 3 examined the longitudinal relationships among variables assessed in patients at the hospital and outcome variables assessed up to six months post-hospitalisation (n = 26). Study 4 (N = 77) determined the concurrent relationships among psychological variables assessed in posthospitalisation patients, and compared the psychological characteristics between posthospitalisation patients and the in-hospital patients in Study 2. A notable feature of the findings obtained from Studies 2, 3 and 4 was that whilst some psychological variables were predictive of outcome variables, others failed to support findings obtained in the West. Self-referent beliefs, for example, significantly predicted intention to attend CRP but did not significantly predict actual attendance. In addition, negative affect was relatively low for patients at in- and post-hospital assessments. Accordingly, Study 5 (N = 300) was conducted to explore possible origins of the lack of consistent findings of the studies on Malaysian cardiac samples. It assessed perceptions of illness constructs in healthy individuals. The findings of this study revealed that perceptions of illness constructs were predictive of healthful behaviors. The findings also revealed the importance of looking at specific cultural factors such as spiritual beliefs in explaining treatment-seeking behaviours in non-Western societies such as Malaysia. In conclusion, the findings of this research project highlighted the importance of studying health and illness-related behaviors within the socio-cultural contexts in which the illness occurs. Although models developed in the West may be applicable in these non-Western, collectivistic societies, the constructs assessed may not be sufficient in accounting for the variance in explaining psychological and behavioral outcomes of illness. Thus, in addition to the constructs found to be predictive of these outcomes on Western patients, psychological studies done in Malaysia should also assess mental representations of illness that are specific to Malaysians.

Thesis (Ph.D. )--University of Tennessee Health Science Center, 2007.
Title from title page screen (viewed on May 16, 2008 ). Research advisor: Gerald I. Byrne, Ph.D. Document formatted into pages (xi, 114 p. : ill.). Vita. Abstract. Includes bibliographical references (p. 65-107).

The purpose of this study was to examine the role of anger/hostility on physiological and behavioral coronary heart disease risk factors. It was hypothesized that anger/hostility would contribute to the severity of CHD via consummatory behaviors such as smoking, poor diet, and excessive alcohol consumption. Some researchers suggest that negative consummatory behaviors play a direct causal role in CHD. The present study proposed that hostility predisposes an individual to these behaviors, and that these behaviors in turn, contribute to CHD. Further, it was proposed that some of the anger that exists in CHD patients may result from the individual being unable to participate in some of their previous consummatory behaviors after suffering a myocardial infarction. Also, it was hypothesized that the construct of anger/hostility would be differentially related to consummatory behaviors.

Data were collected from the initial symptomâ limited maximal exercise tests of 161 patients without. diagnosed coronary heart disease (CHD). Subjects were grouped according to their systolic (SBP) and diastolic (DBP) blood pressure changes between the final two stages of exercise.
Master of Science

The programme of work comprised two maj or aspects of enquiry. Firstly, the work aimed to identify specific situations which promote the Type A coping response. Secondly, the research aimed to investigate the biological mechanisms by which Type A behaviour may be translated into coronary heart disease. Specifically, the sympathetic adrenomedullary process operating via platelet and prostaglandin activity provided a major focus of the work. Type A's (defined by both the Bortner and Thurstone Scales) have been shown to perceive performance tasks as more threatening than Type B's. not only by their enhanced cardiovascular reactivity (heart rate and systolic blood pressure), but also by their superior word recall performance. Dyadic interactive situations, in which combinations of Type A's and Type B's work together on a task, and only one member of the dyad has response control, promote intriguing behavioural, and cardiovascular coping patterns. On a difficult task, Type A dyads (and dyads in which Type A's lacked response control) performed poorer than other dyadic combinations. Cardiovascularly, Type A's demonstrated the greater heart rate, systolic and diastolic pressure, and slower cardiovascular recovery, particularly, if they lacked control of responding, or were paired with another Type A. A long-term naturalistic study provided validity for the acute laboratory tasks. Behavioural, cardiovascular and haematological response patterns, and the timing of reactivity, differentiated Type A's from Type B's. Whilst preparing for and following final year examinations, Type A individuals demonstrated the greater elevations in heart rate, systolic and diastolic blood pressure, plasma adrenaline and noradrenaline. They also demonstrated the faster platelet aggregation (although percentage aggregation decreased similarly for both groups), together with the greater increase in the anticoagulant, antithrombin III. The complexity of these haenatological findings encouraged the examination of two prostaglandins which control platelet function (the coagulatory thromboxane A2 , and the anticoagulatory prostacyclin). Different response patterns emerged prior to, and following a mental arithmetic challenge. The task anticipation effect involved elevated heart rate, systolic and diastolic pressure, plasma adrenaline and prostacyclin. Type A's demonstrated the greater reactivity in all parameters. Following the task, a decrease in the percentage and speed of aggregation was recorded, together with an increase in plasma noradrenaline and thromboxane A 2 . At this stage, Type A's demonstrated the faster platelet aggregation, and the greater noradrenai.ine levels. The thromboxane/prostacyclin ratios, however, remained similar for both groups. The Type A psychobiological response pattern, characterised by the greater magnitude and duration of potentially pathological cardiovascular and hasnatological parameters, may exert profound effects on the development of atherosclerosis and the onset of clinical coronary events.

The dietary outcomes of a school-based heart health promotion program in a low-income, multiethnic, inner-city neighbourhood of Montreal, Canada, were investigated. Eight intervention schools and sixteen control schools participated in the project from 1993 to 1997. Twenty-four hour recall data, as well as data on anthropometric and sociodemographic characteristics, were collected from a subsample of all students in grades 4--6 (aged 9--12 years) at baseline (n = 498), after two years (n = 491), and after four years (n = 347). There were no significant differ in nutrient intakes between 1995 and 1997, so these data were combined for analyses. Compared to students in control schools, students exposed to the program had a significantly increased mean intake of vitamin C per 1000 kcal (4184 kJ) (p = 0.0013). Compared to students in designated intervention schools at baseline, mean make of vitamin C per 1000 kcal was significantly increased (p = 0.002) and mean folate intake was significantly domed (p = 0.0058) in exposed to the program. When the intervention group was restricted to only those students who had received 16 hours or more of program exposure (n = 113), there were no significant differences in any nutrient intakes when compared to control students or students in intervention schools at baseline. This program was unsuccessful in changing nutrient intakes of school-aged children, contributing further evidence that conscious dietary change is difficult to achieve by means of a school-based program with a reasonable number of curriculum hours.

Congenital heart disease (CHD) is the most common birth defect in infants. Identifying factors that are critical to embryonic heart development or CHDs in general could further our understanding of the disease and may lead to new strategies of its prevention and treatment. Endothelial nitric oxide synthase (NOS3/eNOS) is known for many important biological functions including vasodilation, vascular homeostasis and angiogenesis. Previous studies have shown that deficiency in NOS3 results in congenital septal defects, cardiac hypertrophy and postnatal heart failure. In addition, NOS3 is pivotal to morphogenesis of aortic valve and myocardial capillary development. The aim of my thesis was to investigate the role of NOS3 in the embryonic and adult heart. I discovered that NOS3 deficiency resulted in coronary artery hypoplasia in fetal mice and spontaneous myocardial infarction in postnatal hearts. Coronary artery diameters, vessel density and volume were significantly decreased in NOS3-/- mice at postnatal day 0. Lack of NOS3 also down-regulated the expression of Gata4, Wilms tumor-1, vascular endothelial growth factor, basic fibroblast growth factor and erythropoietin in the embryonic heart at E12.5, and inhibited migration of epicardial cells into the myocardium. In addition, my data show that the overall size and length of mitral and tricuspid valves were decreased in NOS3-/- compared with WT mice. Echocardiographic assessment showed significant regurgitation of mitral and tricuspid valves during systole in NOS3-/- mice. Immunostaining of Snail1 was performed in the embryonic heart. Snail1 positive and total mesenchymal cells in the AV cushion were decreased in NOS3-/- compared with WT mice at E10.5 and E12.5. Finally, in the adult aortic valves, NOS3 is important in inhibition of thrombosis formation. Deficiency in NOS3 leads to aortic valve thrombosis and calcification. At 12 months old, 72% (13/18) of NOS3-/- mice showed severe spontaneous aortic valve thrombosis compared with WT mice (0/12). Ex vivo culture of aortic valves showed that platelet aggregation and adhesion were significantly increased in NOS3-/- aortic valves compared with WT aortic valves. There was also a significant regurgitation of the aortic valve during systole in the NOS3-/- compared with WT mice. In addition, NOS3 deficiency resulted in significant aortic valve stenosis, calcification and fibrosis. In summary, these data suggest NOS3 plays a critical role in embryonic heart development and morphogenesis of coronary arteries and inhibits thrombosis formation in the adult aortic valves.

The emphasis of the study was to determine the degree of correlation between the Conicity Index and known risk factors for heart disease. Conicity Index was shown in one study to be a useful screening tool in assessing the relationship between body composition and risk for heart disease. This study was designed to provide nutrition education and teach lifestyle modification to fourteen Veteran's Affairs patients. Change in specific risk factors including Waist-to-Hip Ratio, Body Mass Index, serum lipid levels and dietary intakes were correlated with change in Conicity Index over the six month study. Results from the present study did not suggest that the Conicity Index would serve as an effective screening tool for the present population. Mean body weight, body mass index, hip circumference, cholesterol and triglyceride levels, total caloric and fat intake all decreased significantly as a result of the program. Through nutrition education, behavior modification and group support, the risk for heart disease was successfully modified in this population.
Department of Family and Consumer Sciences

Recent research has shown that the combination of high triglyceride (TG) levels and low high density lipoprotein (HDL) levels, significantly increases the incidence of coronary artery disease (CAD). The incidence of CAD is also increased in abdominally obese individuals. To assess differences in postprandial TG clearance patterns between abdominally obese (AO) and controls (C), fourteen healthy, normolipidemic males (seven controls and seven abdominally obese) completed an oral fat loading test (78 grams of fat). Blood samples were collected every hour for eight hours. Abdominally obese individuals had significantly greater TG values, significantly lower total HDL and HDL2 values and significantly greater area under the TG curve (p = 0.03). Time to reach peak TG and time to reach baseline TG values did not differ between the two groups, even though fewer AO individuals reached baseline within eight hours. The data from the present investigation indicate that increased time to clear TG in AO individuals may be one pathway that increases the incidence of CAD in this group.
School of Physical Education

Given the presumed importance of cardiovascular reactivity and the role of anger in the development of hypertension and coronary heart disease, this study is the first to jointly examine three related areas (i.e. gender effects, anger direction preference, and opportunity/no opportunity to aggress following an anger Inducing situation). The present study tested the following hypotheses: a) that cardiovascular reactivity would vary as a function of subjects' gender and direction preference; b) that the rate of cardiovascular recovery would vary as a function of anger direction preference and opportunity/no opportunity to aggress; c) that the subjective feelings of anger after harassment would vary as a function of gender, anger direction preference, and opportunity/no opportunity to aggress; and d) that the evaluation of experimenter's competency and performance would vary as a function of anger preference. 56 females and 49 males executed a math task while being harassed for "poor performance". Next, they were randomly assigned to either write a negative evaluation of the frustrator or to copy a neutral paragraph and then to circle some letters in another paragraph. Heart rate and blood pressure were measured intermittently throughout. Subjects' preferred mode of anger expression (i.e. anger-in versus anger-out) had been previously assessed and cross validated by self as well as peer evaluations. Results indicated that gender was a better predictor than anger direction preference for cardiovascular reactivity to harassment. Complex patterns of recovery were detected with Intriguing sex differences. Results on male diastolic recovery were consistent with a matching hypothesis of anger direction preference but only for anger-out males. In addition, subjective anger for males was related to opportunity/no opportunity conditions, whereas females did not show such a relationship. Female anger-ln's showed quicker systolic recovery than anger-out's. Lastly, the evaluation of experimenter's competency and performance did not vary as a function of anger preference. Therapeutic implications of the findings within the context of anger control as well as trends for future research are discussed.
Arts, Faculty of
Psychology, Department of
Graduate

Background: Lipoprotein(a) [Lp(a)] is composed of a low density-lipoprotein (LDL) particle and a glycoprotein molecule known as apolipoprotein(a) [apo(a)]. Apo(a) exists in several differently-sized isoforms and is responsible for the unique properties of Lp(a). Although Lp(a) has been known for the past 40 years its relationship with coronary heart disease (CHD) has not been characterized in sufficient detail. Whether Lp(a) causes CHD is not clear. Furthermore, the role of apo(a) isoform variation and other sources of Lp(a) heterogeneity (e.g., level of oxidized phospholipids) in Lp(a)-disease association has not been determined. Objectives: To characterize in detail the association of circulating Lp(a) levels with the risk CHD To assess the nature of Lp(a)-CHD association using an integrative genetic study To explore the role of Lp(a) heterogeneity in its association with CHD Data sources: 1. The Emerging Risk Factors Collaboration (ERFC) database (36 studies, 127,000 participants) 2. The European Prospective Investigation of Cancer – Norfolk (EPIC-Norfolk) study (2200CHD cases, 2200 controls) 3. The Pakistani Risk of Myocardial Infarction Study (PROMIS) (1800 MI cases and 1800 controls) 4. Systematic quantitative reviews of published epidemiological studies Results: ERFC data - Analyses of cross-sectional data on up to 127,000 participants (predominantly of European descent) demonstrated that Lp(a) is generally not strongly correlated with known CHD risk factors. Weakly positive correlations were observed with LDL-cholesterol, apolipoprotein B100 and fibrinogen. Levels were over 2-fold higher in Blacks compared to Whites. Analyses of available data on repeat measurements in 6600 participants demonstrated that Lp(a) values have very high long-term within-person consistency (regression dilution ratio ~ 0.9). Outcome data involved 9300 incident CHD events, 1900 ischaemic strokes and 8100 nonvascular deaths. The risk ratio for CHD per 1SD higher Lp(a) concentration, adjusted for age, sex, lipids and other conventional vascular risk factors, was 1.13 (95% CI, 1.09-1.18). The corresponding risk ratios for ischaemic stroke and nonvascular death were 1.10 (1.02 – 1.18) and 1.01 (0.98-1.05), respectively. Data were too limited to assess association in nonwhites. PROMIS data – the adjusted odds ratio for MI in South Asians was comparable to that of Europeans. EPIC-Norfolk genetic data - The odds ratio for CHD per 1-SD higher Lp(a) concentration, after adjustment for cardiovascular risk factors, was 1.37 (1.20-1.56). Tagging SNPs rs10455872 and rs11751605 (minor allele frequency: 8% and 18%, respectively) were associated with 207% (95% CI, 188 - 227%) and 38% (31 - 46%) higher Lp(a) concentrations per copy of minor allele, respectively. These SNPs accounted for 35% and 5% of the variation in circulating Lp(a) levels, respectively, and were associated with an odds ratio for CHD of 1.34 (1.14-1.58) and 1.17 (1.04-1.33), respectively. The observed SNP-CHD associations were consistent with expected odds ratios corresponding to the Lp(a) effect of the SNPs. Systematic reviews – meta-analysis of published data from 40 studies (11,300 cases, 47,000 controls) demonstrated that people with smaller apo(a) isoforms have about a 2-fold higher risk of CHD or ischemic stroke than those with larger isoforms. Meta-analysis of published data from 10 studies (1500 cases, 10,200 controls) showed that people in the top third of baseline distribution of oxidized LDL levels have a 1.8-fold higher risk of CHD than those in bottom third. EPIC-Norfolk biomarker data – Levels of oxidized phospholipids were strongly correlated with Lp(a) concentration (r = 0.7, p-value < 0.0001). One SD higher concentration of oxidized phospholipids was associated with an adjusted odds ratio for CHD of 1.31 (1.15-1.49). The risk ratio was no longer significant after adjustment for Lp(a) concentration (1.08; 95% CI, 0.91-1.29). Conclusion: Lp(a) concentration is specifically, continuously and independently associated with the risk of ischaemic vascular outcomes. Available evidence supports the causal role of the particle in CHD. Lp(a) appears to induce vascular damage through causal mechanisms that involve apo(a) isoforms and oxidized phospholipids. A comprehensive study of markers of Lp(a) heterogeneity should help to understand the full impact of Lp(a) on cardiovascular diseases. In addition, further study is needed in nonwhites to assess the relevance of the factor to vascular disease risk in these populations.

[Truncated abstract] This thesis investigates novel methods for the genetic association analysis of haplotype data in samples of unrelated individuals, and applies these methods to the analysis of coronary heart disease and related phenotypes. Determining the inheritance pattern of genetic variants in studies of unrelated individuals can be problematic because family members of the studied individuals are often not available. For the analysis of individual genetic loci, no problem arises because the unit of interest is the observed genotype. When the unit of interest is the linear combination of alleles along one chromosome, inherited together in a haplotype, it is not always possible to determine with certainty the inheritance pattern, and therefore statistical methods to infer these patterns must be adopted. Due to genotypic heterozygosity, mutliple possible haplotype configurations can often resolve an individual's genotype measures at multiple loci. When haplotypes are not known, but are inferred statistically, an element of uncertainty is thus inherent which, if not dealt with appropriately, can result in unreliable estimates of effect sizes in an association setting. The core aim of the research described in this thesis was to develop and implement a general method for haplotype-based association analysis using multiple imputation to appropriately deal with uncertainty haplotype assignment. Regression-based approaches to association analysis provide flexible methods to investigate the influence of a covariate on a response variable, adjusting for the effects of other variables including interaction terms. ... These methods are then applied to models accommodating binary, quantitative, longitudinal and survival data. The performance of the multiple imputation method implemented was assessed using simulated data under a range of haplotypic effect sizes and genetic inheritance patterns. The multiple imputation approach performed better, on average, than ignoring haplotypic uncertainty, and provided estimates that in most cases were similar to those observed when haplotypes were known. The haplotype association methods developed in this thesis were used to investigate the genetic epidemiology of cardiovascular disease, utilising data for the cholesteryl ester transfer protein gene (CETP), the hepatic lipase (LIPC) gene and the 15- lipoxygenase (ALOX15) gene on a total of 6,487 individuals from three Western Australian studies. Results of these analyses suggested single nucleotide polymorphisms (SNPs) and haplotypes in the CETP gene were associated with increased plasma high-density lipoprotein cholesterol (HDL-C). SNPs in the LIPC gene were also associated with increased HDL-C and haplotypes in the ALOX15 gene were associated with risk of carotid plaque among individuals with premature CHD. The research presented in this thesis is both novel and important as it provides methods for the analysis of haplotypic associations with a range of response types, while incorporating information about haplotype uncertainty inherent in populationbased studies. These methods are shown to perform well for a range of simulated and real data situations, and have been written into a statistical analysis package that has been freely released to the research community.

The purpose of this study was to determine the effect of a light-moderate versus hard exercise intensity on health and fitness benefits in a previously sedentary population. Twenty-six subjects, 17 male (mean age 45 + 3 yrs), 9 female (mean age 48 + 3 yrs) with at least one coronary artery disease risk factor volunteered to participate in this study. Subjects underwent laboratory testing comprising of, resting heart rate and blood pressure, body composition, blood lipid analysis and aerobic capacity (V02 ), prior to and 22-32 weeks after participating > 2 days per week in the Adult Physical Fitness Program (APFP) at Ball State University. After an initial exercise prescription subjects self selected an exercise intensity between 40-80% of their maximal heart rate range (MHRR) at which to train. Subjects were then grouped into those who trained at < 60% (light-moderate) and those who trained at > 60% (hard) of their MHRR.Those that self selected a hard training intensity did show a significantly greater decrease in diastolic blood pressure than the light-moderate intensity group. Subjects received a main training effect with a mean decrease in systolic blood pressure (123 ± 2.8 to 119 ± 2.4 mmHg), diastolic blood pressure (78 ± 2.2 to 75 ± 1.7 mmHg), and mean increases for HDL-cholesterol (49 ± 2.5 to 53 ± 2.8 mg/dL), absolute functional capacity (2.676 +.162 to 2.843 +.169 L/min) and relative functional capacity (30.2 ± 1.5 to 32.8 + 1.8 ml/kg/min). In conclusion this study demonstrated health and fitness benefits when training at least 2 days per week with greater effects when training at a hard versus light-moderate intensity with regards to diastolic blood pressure.
School of Physical Education

The Type A personality has been associated with coronary heart disease and other psychosomatic illnesses. Previous investigators have suggested that a major stress-related feature of the Type A personality is "excessive" striving for achievement, even though ambition is often conceptualized as a positive aspect of personality. The purpose of the present dissertation was to examine whether there are psychological differences in how Type A individuals, compared to their Type B counterparts, approach and respond to an achievement situation, which, in addition to defining the Type A personality, have potential pathogenic health and personal adjustment implications. Three experiments are reported which examined self-directed behavior in an achievement situation where subjects were required to perform sequential general information tests. The results of Experiment I support the hypotheses that Type A individuals, compared to Type B individuals, adopt very high standards for performance, which increase the probability that they will not achieve their personal goals. The results of Experiment II expand on the findings of Experiment I by indicating that in addition to not achieving personal goals, Type A individuals, relative to Type B individuals, also tend to devalue their actual performance. Furthermore, failure to achieve personal goals was associated with increased self-report of psychological distress. The findings of Experiment III replicate previous results and further indicate that failure to achieve personal goals is associated with specific negative consequences of increased anger and decreased self-esteem. The results also indicate that Type A individuals compared to Type B individuals, tend to make internal attributions for failure, while at the same time, they take less personal credit for success. Finally, the results of Experiment III suggest that the Type A personality is related to general negative affective states, psychosomatic illness, and daily stress. Results of the three experiments indicate that there are important psychological characteristics of how Type A individuals approach and respond to an achievement situation, which appear to have pathogenic health and personal adjustment consequences. Recent reconceptualizations of the Type A personality have emphasized a trait-like dimension of hostility, characterized by cynicism, resentment, and suspiciousness toward others as the "toxic" component of the Type A personality. The present study urges that striving toward lofty goals, devaluation of performance, self-blame for failure without taking comparable self-credit for success, along with negative self-evaluation also be viewed as important unhealthy aspects of the Type A personality.
Ph. D.

Heterotaxy refers to the abnormal arrangement of internal organs in relation to each other. Model organism studies have shown that functions of more than eighty genes are required for normal asymmetric left-right organ development. CRELD1 has been shown to be necessary for proper heart development and mutations in CRELD1 are known to increase risk of cardiac atrioventricular septal defects (AVSD). AVSD is the most common form of heart defect associated with heterotaxy, and we have previously shown that some individuals with heterotaxy-related AVSD have mutations in CRELD1. Therefore, we propose to examine the CRELD1 gene in a large sample of patients with heterotaxy syndrome. Our goal was to determine if mutations in CRELD1 are associated with other manifestations of heterotaxy or if they only coincide with AVSD. To achieve this aim, a sample size of 126 patients with heterotaxy collected by Dr. Belmont, Baylor college of Medicine, Texas, with approximately 66% of the heterotaxy population with different types of heart defects, were used for this study. Ten exons, promoter regions, and regulatory elements in the introns of CRELD1 gene were sequenced and analyzed. In this study three different heterozygous missense mutations in CRELD1 were identified in three unrelated individuals. These three individuals were diagnosed with different forms of heart defects in addition to AVSD. All three mutations were identified in highly conserved regions of CRELD1 possibly altering the CRELD1 properties. This demonstrates that mutations in CRELD1 may increase the susceptibility of AVSD in heterotaxy population. This information can help us to find factors effecting disease susceptibility in heterotaxy patients since the heart defects are a complex trait with incomplete penetrance.

Background: Normative values of VO2max have been developed or updated based on the estimated VO2max, but measured normative values of VO2max have not been developed yet. VO2max has been reported to relate to coronary heart disease (CHD) risk factors, yet most of the studies have used estimated VO2max to compare CHD risk factors. Therefore, the purpose of this study was to develop norms for VO2max from the Ball State University (BSU) Adult Physical Fitness Program cohort that represented percentiles based on the measured VO2max. In addition, this study evaluated the relationship between measured VO2max and six coronary heart disease (CHD) risk factors, which include Body Bass Index (BMI), high density lipoprotein cholesterol (HDL-C), glucose, triglyceride (TG), total cholesterol (TC) and resting blood pressure (BP).Methods: Subjects were healthy men (N=1,867) and women (N=1,253), ranging in age from 19 to 75 years, who completed the standard BSU Adult Physical Fitness Program quiet and exercise testing sessions between 1971 and 2000, with the graded exercise testing (GXT) conducted with one of the following protocols including modified walking, running, Balke, Bruce, and BSU/Bruce ramp. To be included, subjects had to achieve respiratory exchange ratio (RER) >1.0 during their exercise test.Results: All subjects were classified into ten group determined by deciles of VO2max for each decade of age for males and females respectively. A linear regression showed that VO2max decreased 10.1% per decade (0.44 mi.kg'•min'•yr') for men and 9.7% per decade (0.32 ml•kg-l.min-l.yr') for women. There was no significant difference in the rate of agerelated decline in VO2max per decade between men and women or between deciles of VO2max. Also, the percent of subjects with an exercise history code >5 (regularly participate in exercise at least 3 days per week) was higher in the higher VO2max deciles. In addition, five positive CHD risk factors were inversely related to VO2max, and one negative CHD risk factor was directly related to VO2max. As expected, the higher CRF groups had a more favorable CHD risk factor profile. Also, the mean of VO2max decreased with the greater number of CHD risk factors.Conclusion: This study developed normative values of the VO2max based on measured VO2max. VO2max was significantly correlated to CHD risk factors.
School of Physical Education, Sport, and Exercise Science

The purpose of this study was to evaluate whether the current CDC/ACSM physical activity recommendation, ("30 minutes or more of accumulated moderate-intensity activity, most if not all, days of the week") would improve women's health through a reduction ofcoronary heart disease (CHD) risk factors. Twenty-one sedentary females (ages 49 ± 7 yrs.) with one or more CHD risk factors underwent baseline laboratory including: resting heart rate and blood pressure, resting electrocardiogram, body mass index, bioelectrical impedance, skinfold measures, waist-to-hip, blood lipid profile, and V02max. The VO2 was determined by an exercise treadmill test using the Ball State University Ramp protocol. The subjects were instructed on the CDC/ACSM recommendation, the physical activity survey, and given examples of moderate-intensity activity. The survey data was collected bimonthly over the six month period. The subjects reported participating in >_ 30 min. of moderate-intensity activity an average of 4 f 1 days/week with an average duration of 54 ± 26 min. On the remaining days, the subjects reported doing an average of 14 ± 6 minutes per day. Also, 90% of the women reported doing the activity in continuous bouts. Following the six month study period, the women were retested in the laboratory. Sixteen subjects completed the post-testing. The results of the sixteen women showed a significant improvements in HDL-cholesterol (51 ± 15 vs.56 ± 15 mmHg; p=<.05) and TC/HDL ratio (4.5 ± 1 vs.4.25 ± 1.3; p=<.05). There were no significant changes in the other risk factor variables examined or their V02,„.. It was concluded that the majority of previously sedentary, middle aged women can not meet the CDC/ACSM recommendations for daily activity and total energy expenditure. Additionally, it appears that when given the choice, these women choose to do activity in continuous time blocks versus breaking the daily activities into shorter time periods.
School of Physical Education

There is extensive evidence that the rehabilitation of individuals with coronary heart disease needs to include psychological components to complement the exercise and dietary recommendations that are normally provided. However, psychological aspects have not been integrated into medical care in South Africa to any significant degree. Psychological interventions overseas have included the modification of the Type A behaviour pattern, stress management, cognitive restructuring, relaxation techniques, improved communication skills, the identification and expression of emotions, and emotional support. The aim of the present study was to design a short-term group intervention which incorporated these aspects and which included an exploration of the mind-body experience post infarct. In addition, the intervention aimed to increase participants' awareness of the compensatory dynamics of the Type A behaviour pattern. The intervention was tailored to South African conditions and was evaluated by means of a multiple case study design. The intervention was delivered to a group of nine coronary heart disease patients which included six survivors of myocardial infarction, the remaining participants having undergone a by-pass operation. Data included weekly feedback sheets evaluating each session, repeated measures on the Profile of Mood States, the Jenkins Activity Survey, a Spouse Rating Scale and extensive qualitative data on each participant including tape recordings of each session and data collected from a series of interviews before, during and after the programme. The feedback sheets and recordings of the sessions were used as a basis for recommendations for revising the content and structure of the programme for future use. Case narratives were written for three of the participants and provided an in-depth look at how and why individual changes did or did not occur in response to the intervention. In addition, the case narratives revealed the role played by the compensatory dynamics of the Type A behaviour pattern in complicating rehabilitation for survivors of myocardial infarction. Two participants were offered a series of individual sessions at 18-month follow-up and the material from these sessions was also used to aid in the interpretation of the data. The content of the 18-month follow-up sessions provided evidence for the importance of conducting a developmental analysis of the origins of low self-esteem and insecurity that maintain and drive the Type A behaviour pattern. In these sessions, this analysis provided the basis for a brief focused psychodynamic psychotherapy that facilitated marked changes that had not been achieved in the 12-week structured group intervention. It is recommended that future research investigate the use of brief psychodynamic psychotherapy on an individual basis as a complement to a group intervention focusing on psycho-education, building social support and management of problematic emotions in everyday situations.

Cardiovascular disease is one of the leading causes of death in industrialized nations. Research indicates that job strain may be significantly related to cardiovascular disease in employees with little to no social support. Using the JDC-S model developed by Karasek (1979) and elaborated upon by Johnson and Hall (1988), the family-supportive supervisory behaviors (FSSB) measure created by Hammer et al., (2009), and the blood pressure wrist monitor device Omron317T, this study examined FSSB as a moderator of the relationship between job strain, job demands, job control and workers' blood pressure on work and non-work days. Sixty-nine grocery store workers from a Midwest grocery store chain participated in this study, fifty-six of which were included in the analyses. Though none of the interactions were significant at the .05 level, results indicate that FSSB is significantly related to a number of blood pressure readings at the grand centered mean of job strain, job control, and job demands.

The relationship of coronary-prone behavior, hostility, and defense style to atherosclerosis was examined. Subjects were 1,271 patients who underwent coronary angiography at Duke University Medical Center between 1974 and 1980. Type A behavior was assessed using both the Structured Interview and Jenkins Activity Survey. The Cook and Medley Hostility scale and Byrne's Repression-Sensitization scale, both subscales of the Minnesota Multiphasic Personality Inventory, were employed to measure hostility and defense style. The results revealed no significant association between the disease end-points CADSEV, history of myocardial infarction, and history of angina pectoris and either the Structured Interview Type A, hostility, or repression-sensitization, Jenkins Activity Survey defined Type B's, however, were found to more frequently complain of angina. It was suggested future research employ longitudinal or process designs to focus on adaptive functioning from a transactional and developmental perspective which may serve to promote coronary resistance.

[Truncated abstract. Please see the pdf format for the complete text.] The discovery of the C282Y mutation and its role in the development of hereditary haemochromatosis has allowed a greater understanding into the effects of iron overload and its involvement in other conditions such as diabetes and heart disease. It has also allowed the better classification of heterozygotes, who were previously only diagnosed through the use of family studies. There are however, areas of conflict between phenotyping and genotyping methods. My research involved examining the relationship between Haemochromatosis and certain diseases such as diabetes and heart disease; genotyping versus phenotyping discrepancies and the possible interaction of secondary mutations. In Chapter 3 a population study was undertaken with the aim of comparing genotyping versus phenotyping methods as well as increasing general practitioner awareness regarding hereditary haemochromatosis and its diagnosis. It was determined that a minimum of 5000 subjects would be required to give the study sufficient power. Individuals were to be between the ages of 20—40 years, and thus presumably presymptomatic. Participation was entirely voluntary and a consent form was to be signed. Recruitment of subjects proved to be difficult and there was a selective bias towards individuals already displaying symptoms of haemochromatosis. In total less than a 100 subjects were recruited for the study. There were several issues encountered in the implementation of this study. Firstly the number of GPs participating was probably insufficient to recruit the subjects required. A more extensive campaign was probably required to enroll more GPs. Secondly it is very difficult for a busy GP to find the time necessary to explain the study to each of his patients and to get them to sign the consent form. Finally a bias developed in some of the requests. The subjects participating in this study were supposed to be random but in many cases the GPs had enrolled them in the study because they had symptoms of iron overload. In effect the biggest obstacle this study faced was the recruitment of subjects. Due to the small number of subjects little statistical data could be obtained from this study. It was noted, however, that genotyping methods detected two individuals who were homozygous for the C282Y mutation. Both also had increased transferrin saturation levels. Phenotyping detected 5 individuals with increased transferrin saturation. The three others detected via phenotyping were C282Y heterozygotes. Haemochromatosis has long been though to be related to the development of diabetes due to the effect of iron overload on the pancreas. If this is so it would be logical to assume that the prevalence of haemochromatosis would be higher in a diabetic population. Chapter 4 examined the possibility that diabetics have a higher frequency of the C282Y mutation. A population group consisting of 1355 diabetics was genotyped for the C282Y mutation and iron studies were performed on all heterozygotes and C282Y homozygotes. Initial findings indicated that there was a significant difference between the diabetic and control population. However, this finding was the opposite of what was expected, there seemed to be a decreased frequency of the Y allele in the diabetic population rather than an increased one. The control and diabetic populations were not matched in terms of ethnicity. The removal of the ethnic bias in the diabetic population altered the statistics so there was no longer a significant difference between the two groups. This study highlighted the importance of using appropriate control populations as comparison groups. The final results of the study indicated that there was no significant difference between the diabetic population and the control population. This would seem to indicate that there is not an increased occurrence of the C282Y mutation in the diabetic population when compared to the control group. Chapter 5 considered the possible association between C282Y heterozygosity and cardiovascular disease as well as the potential for early mortality. Several recent studies have indicated that C282Y heterozygosity may be a risk factor for the development of atherosclerosis, possibly on the basis of increased iron loading. Using a control population and a population of individuals with known coronary events the incidence of the C282Y mutation was compared against other risk factors. C282Y heterozygosity did not appear to be a risk factor for atherosclerosis. There was however, a statistically significant link between increased ferritin in women and carotid plaques. A population of elderly women was genotyped in order to examine the effects of C282Y heterozygosity on longevity. The first hypothesis addressed in chapter 5 was that C282Y heterozygosity was a risk factor for the development of coronary heart disease.

Cognitive ratings that use bipolar constructs based upon similarity and contrast have been shown to be biased towards the similarity pole in approximately a 62/38 ratio. This bias has also been known to shift in the contrastive direction for individuals who have psychiatric problems. This quantitative measure of cognitive change has a potential for characterizing cognitive changes that occur during the disease process, including recovery from disease. The present study investigated changes in self-aspect ratings and bipolar construct use in adult male veterans who had undergone coronary artery bypass graft surgery. Results indicated that treatment subjects' self-aspect and construct ratings were more negative than controls'. Results also indicated that all subjects rated core interpersonal self-aspects closest to the expected bias, while self-aspects related to cardiac recovery problems were rated in the most contrastive direction. The results finally suggested that the greatest degree of change for the treatment subjects were in emotionally generated constructs. The results suggested a preliminary validation for characterizing cognitive changes in the disease process by measuring shifts in bipolar construct ratings.

Thesis (MTech (Biomedical Technology))--Cape Peninsula University of Technology, 2006
Research has shown that the activation of the NO-cGMP pathway leads to myocardial protection from oxidative stress conditions, such as ischaemia and reperfusion. Few of these studies have however combined diet induced oxidative stress with ischaemia/reperfusion injury. Although little is known about the effects of supplements such as red palm oil (RPO) on the NO-cGMP pathway, research has shown that dietary RPO-supplementation improved reperfusion aortic output recovery through mechanisms that may include activation of the NO-cGMP- and inhibition of the cAMP pathway. RPO is an antioxidant-rich oil containing ~carotene and Vitamin E (tocopherols and tocotrienols). The aims of this study were to determine: 1) whether RPO-supplementation of an oxidative risk induced diet (ORD) and a high saturated fat diet (HFD) offers protection against ischaemia/reperfusion injury in the isolated perfused rat heart and 2) the possible mechanisms for this protection. Male Wistar rats were randomly divided into four groups for a period of 14 weeks according to the dietary supplementation they received. The control groups received either an oxidative risk induced diet (ORD) or a high saturated fat diet (HFD), while the experimental groups received an ORD supplemented with RPO (ORD+RPO) or a HFD supplemented with RPO (HFD+RPO).

Cardiovascular disease is the leading cause of death in the United States. Chronic short sleep duration is also a significant public health problem and has been linked to several markers and outcomes of cardiovascular disease. To date, inconsistency of assessments of sleep duration and insufficiency, use of covariates, and cardiovascular disease measurement across studies limits strong conclusions about the relationship between sleep duration, sleep insufficiency, and cardiovascular disease. The current study examined the association between sleep duration, sleep insufficiency, and a marker of preclinical coronary heart disease (i.e., carotid intima-media thickness) in a community sample using a cross-sectional design. Some evidence for a relationship between sleep duration and cIMT was found, with longer sleep duration predicting higher cIMT in some segments. Additionally, the interaction between sleep duration and sleep insufficiency was significant. However, neither of these effects were significant after adjusting for age and in some cases race/ethnicity, suggesting demographics may explain this association. Actigraphy and sleep diary duration assessments demonstrated significantly different correlations with cIMT in some segments, suggesting the nature of the assessment method may impact the strength or direction of the relationship between sleep duration and cIMT. Limitations and future directions are discussed.

The purpose of the research was to describe the relationships between social support and role strain and preventative health behaviors. The sample consisted of 62 critical care nurses employed in three southwest acute care facilities. Subjects completed instruments measuring social support, role strain, and four preventative health care behaviors. Pearson correlations revealed significant positive relationships between social support and personal/household roles women perform and ways women handle stress. Additional significant negative relationships existed between marital/relationship roles women perform and leisure physical activities, a subset of preventative health behaviors. The parental roles, obligations, and responsibilities women perform were also significantly related with leisure physical activities. Conclusions drawn indicate that the critical care nurses did not perceive themselves susceptible to cardiovascular disease and therefore did not participate in preventative health care activities, regardless of perceived helpful social support and an absence of role strain.

[Truncated abstract] The low density lipoprotein receptor-related protein (LRP), a member of the low-density lipoprotein (LDL) receptor gene family is involved in numerous biological processes including lipoprotein metabolism. This thesis concerns investigations into some aspects of LRP metabolism/regulation and possible roles in coronary artery disease (CAD). Specific aims were: to investigate the association between polymorphisms in the LRP gene and in its associated protein, the lipoprotein receptor-associated protein (RAP), with the risk of CAD; to extensively examine the influence of the LRP exon 22 C200T polymorphism on lipid metabolism; to develop and characterise assays for the mRNA expression of LRP and 2 other genes relevant to lipid metabolism, the LDL receptor (LDLR), and HMG CoA reductase (HMGCR); and finally, to apply the latter techniques to studies on the influence of genetic variation in LRP, and dietary and drug interventions, on LRP, LDLR and HMGCR mRNA expression in nucleated blood cells from healthy human subjects. Six hundred CAD subjects and 700 similarly aged controls were genotyped for 8 LRP gene polymorphisms as well as for the RAP V311M polymorphism. ... In the final phase of my studies, I examined the influence of 4 weeks therapy with a cholesterol lowering drug, an HMGCR inhibitor, atorvastatin (20mg daily), on the mRNA expression of LDLR, LRP and HMGCR in human nucleated blood cells. Twelve normal Caucasian male subjects aged 49 ? 5 (SD) years were studied. Plasma total cholesterol and LDL-C decreased by averages of 29 % and 41 % after the 4 week period. This was accompanied by an elevation in LDLR mRNA expression by approximately 30 35 %. In contrast, there was no significant effect on LRP and HMGCR mRNA expression. In conclusion, the original findings in this thesis included: demonstration of a strong influence of the LRP exon 22 C200T polymorphism on coronary artery disease and LDLR expression, but without a clear effect on fasting or postprandial lipid levels; data on the biological variation in LDLR and LRP gene expression in nucleated blood cells from normal subjects; the influence of an oral fat load on the expression viii of these genes, finding that LDLR was significantly depressed; and finally, the observation that statin therapy upregulated LDLR in nucleated blood cells.

The worldwide increasing number of persons affected by largely preventable diseases like diabetes demands better prevention and treatment. Insulin is required for effective utilisation of circulating nutrients. Impaired responsiveness to insulin (insulin resistance, IR) is a hallmark of type 2 diabetes and independently raises the risk of heart attack and stroke. The pathophysiology of IR is incompletely understood. High-throughput measurement of large numbers of circulating biomarkers may provide new insights beyond established risk factors. The aims of this thesis were to (i) use proteomics, metabolomics and genomics methods in large community samples to identify biomarkers of IR; (ii) assess biomarkers for risk prediction and insights into aetiology and consequences of IR; and (iii) use Mendelian randomisation analysis to assess causality. In Study I, analysis of 80 circulating proteins in 70-to-77-year-old Swedes identified cathepsin D as a biomarker for IR and highlighted a tentative causal effect of IR on raised plasma tissue plasminogen activator levels. In Study II, nontargeted fasting plasma metabolomics was used to discover 52 metabolites associated with glycaemic traits in non-diabetic 70-year-old men. Replication in independent samples of several thousand persons provided evidence for a causal effect of IR on reduced plasma oleic acid and palmitoleic acid levels. In Study III, nontargeted metabolomics in plasma samples obtained at three time points during an oral glucose challenge in 70-year-old men identified associations between a physiologic measure of IR and concentration changes in medium-chain acylcarnitines, monounsaturated fatty acids, bile acids and lysophosphatidylethanolamines. Study IV provided evidence in two large longitudinal cohorts for causal effects of type 2 diabetes and impaired insulin secretion on raised coronary artery disease risk. In conclusion, the Studies in this thesis provide new insights into the pathophysiology and adverse health consequences of IR and illustrate the value of combining traditional epidemiologic designs with recent molecular techniques and bioinformatics methods. The results provide limited evidence for the role of circulating proteins and small molecules in IR and require replication in separate studies and validation in experimental designs.

Indiana University-Purdue University Indianapolis (IUPUI)
For years, the leading killer of Americans has been coronary artery disease (CAD), which has a strong correlation to the U.S. obesity epidemic. Obesity, along with the presence of other risk factors including hyperglycemia, hypercholesterolemia, dyslipidemia, and high blood pressure, comprise of the diagnosis of metabolic syndrome (MetS). The presentation of multiple MetS risk factors increases a patients risk for adverse cardiovascular events. CAD is a complex progressive disease. We utilized the superb model of CAD and MetS, the Ossabaw miniature swine, to investigate underlying mechanisms of CAD progression. We studied the influence of coronary epicardial adipose tissue (cEAT) and coronary smooth muscle cell (CSM) intracellular Ca2+ regulation on CAD progression. By surgical excision of cEAT from MetS Ossabaw, we observed an attenuation of CAD progression. This finding provides evidence for a link between local cEAT and CAD progression. Intracellular Ca2+ is a tightly regulated messenger in CSM that initiates contraction, translation, proliferation and migration. When regulation is lost, CSM dedifferentiate from their mature, contractile phenotype found in the healthy vascular wall to a synthetic, proliferative phenotype. Synthetic CSM are found in intimal plaque of CAD patients. We investigated the changes in intracellular Ca2+ signaling in enzymatically isolated CSM from Ossabaw swine with varying stages of CAD using the fluorescent Ca2+ indicator, fura-2. This time course study revealed heightened Ca2+ signaling in early CAD followed by a significant drop off in late stage calcified plaque. Coronary artery calcification (CAC) is a result of dedifferentiation into an osteogenic CSM that secretes hydroxyapatite in the extracellular matrix. CAC is clinically detected by computed tomography (CT). Microcalcifications have been linked to plaque instability/rupture and cannot be detected by CT. We used 18F-NaF positron emission tomography (PET) to detect CAC in Ossabaw swine with early stage CAD shown by mild neointimal thickening. This study validated 18F-NaF PET as a diagnostic tool for early, molecular CAC at a stage prior to lesions detectable by CT. This is the first report showing non-invasive PET resolution of CAC and CSMC Ca2+ dysfunction at an early stage previously only characterized by invasive cellular Ca2+ imaging.

博士
國立臺灣大學
臨床醫學研究所
90
英文簡述（Summary） Dyslipidemia and ensuing atherosclerosis have been implicated in the pathophysiology of coronary heart disease (CHD). A number of prospective studies have established that the risk of cardiac morbidity and mortality is directly related to the concentration of plasma total or low-density lipoprotein (LDL) cholesterol. Furthermore, lipid-lowering therapy has been found to reduce the risk of cardiovascular events in both high-risk individuals and patients with manifest CHD. However, whether dyslipidemia influences the severity of myocardial infarction (MI) is still uncertain. It is noteworthy that, in the Scandinavian Simvastatin Survival Study, the mortality rate of definite MI in the placebo group was 28% higher than that in the simvastatin group. This finding suggests that dyslipidemia may have an adverse effect on the evolution of MI. Likewise, a number of animal and human studies have revealed that hypercholesterolemia can increase the susceptibility of myocardium to ischemic insults by various nonatherosclerotic mechanisms. To examine the hypothesis that dyslipidemia can aggravate myocardial vulnerability in the clinical setting of acute MI and this deleterious effect is not entirely due to the well-known atherogenic properties of dyslipidemia, we performed a retrospective study on 165 patients with a first MI admitted to the coronary care unit from January 1992 to December 1993. All patients underwent measurements of serum lipid profiles 1 week and 3 months after MI, a radionuclide ventriculographic study, and a coronary angiographic study. The patients were divided into 3 groups according to their 3-month serum total cholesterol levels (group 1, <200 mg/dL; group 2, 200 to 240 mg/dL; group 3, >240 mg/dL). Groups 1, 2, and 3 consisted of 66, 59, and 40 patients, respectively. Group 3 had a higher Gensini score than groups 1 and 2, although this was not statistically significant (P=0.13). The postinfarct left ventricular ejection fraction (LVEF) was highest in group 1 (53 ± 13%), at mid level in group 2 (43 ± 14%), and lowest in group 3 (35 ± 11%)(P<0.0001). A significant negative correlation between 3-month LDL cholesterol and postinfarct LVEF after adjustment for all confounding variables was found. The product of peak creatine kinase (CKMAX) and time to CKMAX, and patency of the infarct-related artery, rather than variables of coronary atherosclerosis, were also independent predictors of the postinfarct LVEF. In this study, we have demonstrated, for the first time, that dyslipidemia had a detrimental effect on postinfarct LVEF. Moreover, the detrimental effect of dyslipidemia on postinfarct LVEF was independent of the extent of MI and the patency rate of infarct-related artery. These findings suggest that dyslipidemia may adversely influence the evolution of MI even after the establishment of a patent infarct-related artery, which indicates that reperfusion injury may be the pathogenic link mediating the deleterious effect of dyslipidemia on postinfarct left ventricular systolic function. The deleterious effect of dyslipidemia on postinfarct LVEF being independent of the size of MI estimated by cardiac enzyme elevation is another very intriguing finding. Because the cardiac enzymes are released only when cardiomyocytes break down and cardiomyocytes typically rupture during necrosis but not apoptosis, we therefore speculated that cardiomyocyte apoptosis may play a role in the deleterious effect of dyslipidemia on postinfarct LVEF. In fact, it has been reported that apoptosis is a significant contributor to myocardial cell death as a result of reperfusion injury. However, whether the extent of cardiomyocyte apoptosis following ischemia and reperfusion varies in different pathophysiological background is still uncertain. Accordingly, we designed an experiment to investigate whether prolonged hypercholesterolemia increases the extent of experimental myocardial ischemia-reperfusion injury by aggravating cardiomyocyte apoptosis in a rabbit model (Study #1). Although a large number of genes have been reported to be involved in the regulation of apoptotic cell death, the antiapoptotic Bcl-2 and proapoptotic Bax play major roles in regulating myocardial apoptosis following ischemia and reperfusion. We thus determined the effects of hypercholesterolemia on the expression of Bcl-2 and Bax in the ischemic and non-ischemic myocardium to identify the underlying molecular mechanisms induced by hypercholesterolemia. In view of the significant contribution of cardiomyocyte apoptosis as a result of reperfusion injury, it is speculated that anti-apoptotic interventions, such as caspase inhibitors, may reduce myocardial reperfusion injury by attenuating cardiomyocyte apoptosis within the ischemic area at risk. On the other hand, in addition to apoptosis, various other mechanisms responsible for reperfusion injury have been identified, including the massive generation of oxygen free radicals and inflammatory cytokines. Mechanistically, apoptotic cell death is mediated by a family of aspartate-specific cysteine proteases known as caspases that include at least 14 members. Caspase-1, the first identified member of the caspase family, is responsible for the activation of executioner caspases involved in apoptosis progression in a variety of experimental paradigms. Furthermore, it modulates the inflammatory reaction by processing the maturation of interleukin-1b (IL-1b). Caspase-1 hence has the peculiarity of being involved in the activation of both apoptosis and inflammation, through the intermediate of the pro-inflammatory cytokine IL-1b. Based on these background researches, we speculated that pharmacological inhibition of the caspase-1 cascade might have greater protective effects on myocardial ischemia-reperfusion injury in the context of hypercholesterolemia. In Study #2, we examined whether pharmacological inhibition of the caspase-1 cascade, using Ac-Tyr-Val-Ala-Asp-CH2Cl (Ac-YVAD.cmk), after myocardial ischemia have greater protective effects on myocardial ischemia-reperfusion injury in diet-induced hypercholesterolemic rabbits. Although the observed adverse effect of dyslipidemia on postinfarct LVEF was mostly ascribed as a consequence of dyslipidemia-associated deleterious effects on the evolution of MI, we still can not exclude the possibility that it may in part reflect the baseline left ventricular systolic function. Large-scale clinical trials have shown that long-term treatment with lipid-lowering therapy results in a significant reduction in the occurrence of heart failure among patient with coronary artery disease without previous evidence of congestive heart failure, suggesting dyslipidemia may have an adverse effect on left ventricular performance. Hence, we performed another hospital-based study to examine whether dyslipidemia has a detrimental effect on left ventricular systolic function and whether this effect is dependent on the corresponding severity of coronary atherosclerosis (Study #3). Despite we studied issues regarding dyslipidemia and various aspects of CHD, the definition of dyslipidemia per se is still under debate. Although elevated levels of LDL cholesterol and low levels of HDL cholesterol are independent risk factors for CHD, several important issues in clinical management of dyslipidemic individuals remain to be solved. For example, there is a continuing debate as to whether subjects with high levels of both HDL and LDL cholesterol have an increased risk for CHD. The same problem confronts clinicians in managing subjects with low levels of both HDL and LDL cholesterol. These unresolved issues reflect the inadequacy of current LDL cholesterol-based guidelines. Recent studies have shown that the total cholesterol/HDL cholesterol ratio is a powerful lipoprotein predictor for the development of CHD. Although this concept has not been integrated into current clinical guidelines, it is suggested that using total cholesterol/HDL cholesterol ratio as a stratifying variable may help clinicians to better clarify the risk status of individuals with high levels of both HDL and LDL cholesterol as well as those with low levels of both HDL and LDL cholesterol. In Study #4, by using the 8-year follow-up data of CHD-free participants in a well-characterized Chinese population-based prospective cohort study─the Chin-Shan Community Cardiovascular Cohort (CCCC) study, we first assessed the efficacy of various lipid and lipoprotein measurements at baseline in predicting the risk for future coronary events. Then, we determined the associated risk of CHD in subgroups stratified by different lipid and lipoprotein screening strategies to evaluate the adequacy of current total and LDL cholesterol-based approach in lipid management. Several epidemiologic studies have demonstrated that elevated serum total cholesterol and LDL cholesterol levels lose their predictive power for CHD as people age. However, the underlying mechanisms remained uncertain. To elucidate this issue, in Study #5, we assessed the efficacy of various lipid and lipoprotein measurements at baseline in predicting CHD risk in both the younger (aged 35 to 55 years) and older cohorts (aged ³56 years) by analyzing the same 8-year follow-up data of CHD-free participants in the CCCC study. In Study #1, twenty-eight male New Zealand White Rabbits had been fed with standard chow (control, n = 14) or chow supplemented with 1% cholesterol (hypercholesterolemic, n = 14) for 8 weeks. Anesthetized rabbits were then subjected to 30 minutes of left circumflex artery occlusion followed by 4 hours of reperfusion. Apoptosis was identified as “DNA ladders” by gel electrophoresis and confirmed histologically using the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay. The infarct size (% of risk region) was significantly greater in hypercholesterolemic rabbits than control (39 ± 6% vs. 23 ± 2%, P=0.02). Very few TUNEL-positive cardiomyocytes could be identified in the non-ischemic regions in both groups, consistent with an absence of DNA laddering. In contrast, TUNEL-positive cardiomyocytes were significantly displayed in the ischemic, non-necrotic myocardium and DNA ladder occurred in all animals. The percentage of TUNEL-positive cardiomyocytes in the ischemic non-necrotic myocardium was significantly higher in hypercholesterolemic rabbits compared with control (40 ± 5% vs. 17 ± 1%, P<0.001). Western blot analysis showed that, in the non-ischemic myocardium, hypercholesterolemic rabbits exhibited an approximately 50% increase in the expression of Bcl-2 (P<0.05), but not Bax, than control rabbits. However, compared with control, hypercholesterolemic rabbits exhibited a more pronounced decrease in the expression of Bcl-2 (42 ± 4% vs. 26 ± 2%, P<0.01) and a similar extent of increase in the expression of Bax in the ischemic myocardium. Furthermore, hypercholesterolemic rabbits were associated with markedly increased activation of caspase-1 and caspase-3 within the ischemic myocardium than control rabbits. This study demonstrates that although hypercholesterolemia is associated with an increased myocardial Bcl-2/Bax ratio at baseline, it still significantly exacerbates cardiac reperfusion injury, not only by increasing the infarct size, but also by increasing the extent of cardiomyocyte apoptosis. After demonstrating that hypercholesterolemia is associated with greater myocardial ischemia-reperfusion injury, in which apoptosis and inflammation-mediated necrosis both play a key role, we performed Study #2. In this study, sixty male New Zealand White Rabbits, fed with standard chow or chow supplemented with 1% cholesterol for 8 weeks, were subjected to 30 minutes of left circumflex artery occlusion followed by 4 hours of reperfusion. An intravenous bolus of Ac-YVAD.cmk (1.6 mg kg-1) or vehicle was given 20 minutes after coronary occlusion in each group. Apoptosis was also identified as “DNA ladders” by gel electrophoresis and confirmed histologically using the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay. The infarct size (% of risk region) assessed by triphenyltetrazolium chloride staining was significantly greater in cholesterol-fed rabbits than in normally fed ones (41±6% vs. 26±3%, P=0.003). Postischemic administration of Ac-YVAD.cmk markedly decreased infarct size from 26±3% to 12±2% in normally fed rabbits (P=0.005) and from 41±6% to 14±2% in cholesterol-fed rabbits (P<0.001). In the ischemic non-necrotic area, the percentage of TUNEL-positive cardiomyocytes was significantly greater in vehicle-treated cholesterol-fed rabbits compared with normally fed ones (39.0±2.3% vs 15.5±0.8%, P<0.001), whereas treatment with Ac-YVAD.cmk markedly reduced the percentage of TUNEL-positive cardiomyocytes from 15.5±0.8% to 2.2±0.1% in normally fed rabbits (P<0.001) and from 39.0±2.3% to 2.2±0.1% in cholesterol-fed rabbits (P<0.001). Although myocardial IL-1b levels and activity of both caspase-1 and caspase-3 in the ischemic area were significantly higher in vehicle-treated cholesterol-fed rabbits compared to normally fed ones, Ac-YVAD.cmk treatment resulted in a reduction not only of IL-1b and caspase-1, but also of caspase-3 in both normally fed and cholesterol-fed rabbits. Furthermore, no differences in IL-1b levels and activity of caspase-1 and caspase-3 were observed between Ac-YVAD.cmk-treated normally fed and cholesterol-fed rabbits. This study demonstrates that injection of a selective caspase-1 inhibitor after myocardial ischemia completely abolished the detrimental effect conferred by hypercholesterolemia on myocardial ischemia-reperfusion injury by attenuating both necrotic as well as apoptotic cell death pathways through inhibition of IL-1b production and activation of caspase-1 and caspase-3. In Study #3, 114 consecutive patients with stable angina and a positive exercise thallium-201 myocardial perfusion single-photon emission computed tomography were studied. All patients underwent measurement of serum lipid profiles, right-sided heart catheterization, left ventriculography, and selective coronary arteriography. Mean serum levels of total cholesterol and triglycerides were 4.5 mmol/L and 1.4 mmol/L, respectively. In univariate analysis, a significant positive correlation between serum high-density lipoprotein (HDL) cholesterol and LVEF (r = 0.49, P<0.0001) was found. Patients in the lower tertile of serum HDL cholesterol had a significantly lower mean LVEF than those in the upper tertile (55.9 ± 15.2 vs. 72.8 ± 6.8 %, P<0.0001). Stepwise multiple linear regression analysis revealed that LVEF significantly correlated with HDL cholesterol (P<0.0001), the Gensini score (P=0.008), and diabetes mellitus (P = 0.08)(r = 0.55, P<0.0001). In subgroup analysis of patients with angiographically normal coronary arteries, serum HDL cholesterol was still significantly associated with LVEF. The present study demonstrated an independent association between low HDL cholesterol and subclinical left ventricular systolic dysfunction in Chinese patients with stable angina whose serum levels of total cholesterol and triglycerides were relatively low. Moreover, the correlation between HDL cholesterol and baseline LVEF remained significant even in patients with normal coronary angiograms, suggesting HDL cholesterol might influence left ventricular systolic performance through extra-atherosclerotic mechanisms. In Study #4, we assessed the efficacy of various lipid and lipoprotein measurements at baseline in predicting the risk for CHD and determined the associated risk of CHD in subgroups stratified by different lipid and lipoprotein screening strategies to evaluate the adequacy of current total and LDL cholesterol-based approach in lipid management. We analyzed data from the Chin-Shan Community Cardiovascular Cohort study, a Chinese population-based prospective cohort study since 1990. During an 8-year follow-up, 213 (6.7%) of 3,159 CHD-free participants (aged ³35 years) developed CHD. The total cholesterol/HDL cholesterol ratio was the most powerful lipoprotein discriminator of future CHD (hazard ratio, 1.21 for 1.0 increment in ratio; P<0.001). Subjects with “high-risk” LDL cholesterol levels (>160 mg/dL) and low total cholesterol/HDL cholesterol ratios (£5) had an incidence of CHD similar to those with low levels of both LDL cholesterol (£130 mg/dL) and total cholesterol/HDL cholesterol ratios (4.9% vs. 4.6%). On the other hand, subjects with “low-risk” LDL cholesterol levels (£130 mg/dL) and high total cholesterol/HDL cholesterol ratios (>5) had a 2.5-fold higher incidence of CHD than those with similar LDL cholesterol levels but low total cholesterol/HDL cholesterol ratios (P<0.001). Compared to using LDL cholesterol level of 130 mg/dL as the cut-off point, using total cholesterol/HDL cholesterol ratio of 5 was associated with superior specificity (73% vs. 59%, P<0.001) and accuracy (72% vs. 58%, P<0.001) and similar sensitivity (50% vs. 53%). In Study #5, we first assessed the efficacy of various lipid and lipoprotein measurements at baseline in predicting CHD risk in the younger and older cohorts to understand whether the predictability differed between both age groups. In the younger cohort (35 to 55 years), total cholesterol and LDL cholesterol levels were independently predictive of CHD risk, whereas in the older cohort (³56 years), HDL cholesterol level was a better predictor of CHD risk than total cholesterol or LDL cholesterol levels. Among the lipoprotein measurements examined, the ratio of total to HDL cholesterol was the most powerful lipoprotein predictor of CHD risk in both cohorts. We then divided both cohorts into subgroups of different lipoprotein phenotypes on the basis of serum LDL cholesterol levels and the ratios of total to HDL cholesterol at baseline. Compared with those with an LDL cholesterol level of £130 mg/dL and a total cholesterol/HDL cholesterol ratio of £5, individuals with an LDL cholesterol level of >130 mg/dL and a total cholesterol/HDL cholesterol ratio of >5 (the “high LDL-low HDL cholesterol” phenotype) had an increased CHD risk in both the younger and older age groups (hazard ratios, 2.10 and 2.17, respectively). By contrast, only older individuals with an LDL cholesterol level of £130 mg/dL and a total cholesterol/HDL cholesterol ratio of >5 (the “isolated low HDL cholesterol” phenotype) had an increased CHD risk (hazard ratio, 3.04), whereas the younger counterparts did not. It is noteworthy that individuals with an LDL cholesterol level of >130 mg/dL and a total cholesterol/HDL cholesterol ratio of £5 did not have an increased CHD risk regardless of their age. The present study demonstrated that CHD risk associated with the high LDL-low HDL cholesterol phenotype developed early in adult life, whereas CHD risk associated with the isolated low HDL cholesterol phenotype developed in later life. Conclusions In Studies #1 and #2, we showed that although hypercholesterolemia is associated with an increased myocardial Bcl-2/Bax ratio at baseline, diet-induced hypercholesterolemia significantly exacerbates cardiac reperfusion injury, not only by increasing the infarct size, but also by increasing the extent of cardiomyocyte apoptosis. The increased extent of cardiomyocyte apoptosis may adversely influence the left ventricular remodeling process and subsequently lead to poor prognosis. Because the magnitude of reperfusion-related cardiomyocyte apoptosis is significantly greater in hypercholesterolemic rabbits, we speculated that the administration of anti-apoptotic agents following the establishment of successful revascularization might provide additional benefits in salvaging the ischemic myocardium. Based on these findings, we subsequently demonstrated that pharmacological inhibition of caspase-1 as an adjunct to reperfusion results in a significant cardioprotection from ischemia-reperfusion insult. Furthermore, we presented the first evidence that pharmacological inhibition of caspase-1 completely abolished the detrimental effect conferred by hypercholesterolemia on myocardial ischemia-reperfusion injury. This cardioprotective effect is achieved not only by blocking the apoptotic pathway but also by inhibiting IL-1b-mediated inflammation. These observations indicate that inhibition of caspase-1 could be a promising therapeutic approach to attenuate myocardial damage caused by ischemia and reperfusion, particularly in those with concomitant hypercholesterolemia. Our previous study revealed that dyslipidemia was independently associated with decreased postinfarct LVEF in patients with a first MI. Despite that dyslipidemia-associated adverse effect on the evolution of MI was assumed to be the most important mechanism, as shown in Studies #1 and #2, the present finding of the association between low serum HDL cholesterol and subclinical left ventricular systolic dysfunction in Study #3 suggests that dyslipidemia-associated deleterious effect on baseline left ventricular systolic function may partly contribute to the decreased postinfarct LVEF in dyslipidemic patients observed in our previous study. Moreover, it would be important to investigate whether left ventricular systolic dysfunction could be reversed by vigorous control of abnormal serum lipid profiles. In Studies #4 and #5, we clearly demonstrated that current guidelines for lipid management may misclassify individuals with high levels of both HDL and LDL cholesterol as well as those with low levels of both HDL and LDL cholesterol. Using the ratio of total to HDL cholesterol as the initial screening tool can obviate this discrepancy. Therefore, the definition of dyslipidemia should be revised. We also confirmed that the differential predictability of various lipoprotein measurements for CHD in younger and older cohorts observed in most Western epidemiologic studies was also present in this Chinese population-based prospective study. Furthermore, by using LDL cholesterol level and the ratio of total to HDL cholesterol as the stratifying variables, we explicitly distinguished two atherogenic lipoprotein phenotypes and, for the first time, demonstrated that CHD risk associated with the high LDL-low HDL cholesterol phenotype is consistently increased across a wide age range, whereas CHD risk associated with the isolated low HDL cholesterol phenotype is evident only in older individuals. More importantly, both younger and older individuals with high levels of both HDL and LDL cholesterol did not have an excess risk for CHD. These findings not only delineate the atherogenic risk of different lipoprotein phenotypes, but also elucidate the confusing information regarding the relations between total cholesterol and LDL cholesterol levels and CHD risk in older individuals. It is noteworthy that all published primary-prevention or secondary-prevention lipid-intervention trials included patients with an average total cholesterol/HDL cholesterol ratio far greater than 5. However, the average level of total cholesterol/HDL cholesterol ratio in Western populations is only 4.5. Why there was such a discrepancy is still uncertain. However, the absence of specific clinical trials that document the magnitude of benefit from drug therapy and the low absolute risk in CHD-free individuals with high levels of both HDL and LDL cholesterol allude to the need for more caution when considering aggressive lipid-lowering therapy in this clinical setting.

by Choi Ka Yan.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2000.
Includes bibliographical references (leaves 113-128).
Abstract and appendix in English and Chinese.
Acknowledgements --- p.i
Abstract --- p.ii
Abstract (Chinese version) --- p.iv
Table of Contents --- p.vi
List of Tables --- p.xi
List of Figures --- p.xiv
List of Abbreviations --- p.xv
Chapter CHAPTER ONE: --- BACKGROUND AND LITERATURE REVIEW
Chapter 1.1 --- Coronary Heart Disease: a global health problem --- p.1
Chapter 1.2 --- Risk Factors of Coronary Heart Disease --- p.3
Chapter 1.2.1 --- Age --- p.3
Chapter 1.2.2 --- Gender --- p.4
Chapter 1.2.3 --- Family History of Cardiovascular Disease --- p.5
Chapter 1.2.4 --- Hypercholesterolemia --- p.7
Chapter 1.2.5 --- Unhealthy Dietary Habits --- p.11
Chapter 1.2.6 --- Obesity --- p.14
Chapter 1.2.7 --- Physical Inactivity --- p.20
Chapter 1.3 --- Clustering of Risk Factors --- p.24
Chapter 1.4 --- Risk Factors in Children: Atherosclerosis Begins Early in Life --- p.26
Chapter CHAPTER TWO: --- RESEARCH IN HONG KONG AND PURPOSES OF THIS STUDY
Chapter 2.1 --- Nutrition Transition --- p.27
Chapter 2.2 --- CHD Mortality Trends in Hong Kong --- p.28
Chapter 2.3 --- Serum Total Cholesterol and Obesity in Hong Kong Adults --- p.29
Chapter 2.4 --- "Obesity, Serum Total Cholesterol, Dietary Habits and Physical Activity of Hong Kong Children and Adolescents" --- p.31
Chapter 2.5 --- Study Purpose and Objectives --- p.35
Chapter CHAPTER THREE: --- SURVEY DESIGN
Chapter 3.1 --- Sample Selection --- p.39
Chapter 3.2 --- "Blood Total Blood Cholesterol, Triglyceride and Anthropometric Measurements" --- p.40
Chapter 3.2.1 --- Total Blood Cholesterol and Triglyceride --- p.40
Chapter 3.2.2 --- Anthropometry Measures --- p.42
Chapter 3.3 --- Questionnaire --- p.45
Chapter 3.3.1 --- Questionnaire Design and Pre-testing --- p.45
Chapter 3.3.2 --- General Health and Socio-demographic Questionnaire --- p.47
Chapter 3.3.3 --- Physical Activity Questionnaire --- p.47
Chapter 3.3.4 --- Dietary Questionnaire --- p.48
Chapter 3.4 --- Data Management --- p.49
Chapter 3.5 --- Statistics --- p.49
Chapter 3.6 --- Data Analysis --- p.50
Chapter 3.6.1 --- Blood Total Cholesterol and Triglyceride --- p.50
Chapter 3.6.2 --- Obesity and Fat Distribution --- p.50
Chapter 3.6.3 --- Diet --- p.51
Chapter 3.6.4 --- Physical Activity Patterns --- p.51
Chapter 3.6.5 --- Body Mass Index of Parent and Family History of Diseases --- p.52
Chapter CHAPTER FOUR: --- RESULTS
Chapter 4.1 --- Sample Size and the Characteristics of the Students in the Two Schools --- p.54
Chapter 4.2 --- Gender and Age Distribution --- p.55
Chapter 4.3 --- Blood Total Cholesterol and Triglyceride --- p.56
Chapter 4.4 --- Anthropometry Measures --- p.58
Chapter 4.5 --- Dietary Habits --- p.60
Chapter 4.5.1 --- Dietary Composition of 3-day Dietary Record --- p.60
Chapter 4.5.2 --- Eating Behaviors --- p.65
Chapter 4.6 --- Physical Activity --- p.68
Chapter 4.7 --- Family History of Diseases --- p.70
Chapter 4.8 --- Parents' Anthropometry --- p.71
Chapter 4.9 --- Demographic Data --- p.71
Chapter 4.10 --- Inter-relationships --- p.75
Chapter 4.10.1 --- Blood Total Cholesterol and Triglyceride --- p.75
Chapter a. --- "Blood Total Cholesterol, Triglyceride and Body Fatness" --- p.75
Chapter b. --- "Blood Total Cholesterol, Triglyceride and Diet" --- p.75
Chapter c. --- "Blood Total Cholesterol, Triglyceride and Physical Activity Patterns" --- p.77
Chapter d. --- Blood Total Cholesterol，Triglyceride and Family History of Hypercholesterolemia --- p.78
Chapter e. --- Relative Importance of the Key Factors in Predicting Blood Total Cholesterol levels --- p.79
Chapter 4.10.2 --- Obesity and Body Fatness --- p.79
Chapter a. --- "Obesity, Body Fatness and Physical Activity Patterns" --- p.79
Chapter b. --- "Obesity, Body Fatness and Diets" --- p.82
Chapter c. --- Body Fatness and Genetics --- p.84
Chapter 4.10.3 --- Diet and Physical Activity --- p.86
Chapter 4.10.4 --- "Blood Total Cholesterol, Triglyceride, Obesity and Other Demographic or Economic Characteristics" --- p.87
Chapter 4.11 --- Clustering of Risk Factors among Obese children --- p.87
Chapter CHAPTER FIVE: --- DISCUSSION
Chapter 5.1 --- Implication of Research Findings --- p.89
Chapter 5.2 --- Limitations --- p.108
Chapter CHAPTER SIX: --- CONCLUSIONS AND RECOMMENDATIONS --- p.111
References --- p.113
Appendices
Chapter I --- Questionnaire (English version) --- p.129
Chapter II --- Questionnaire (Chinese version) --- p.139
Chapter III --- Introductory letter (English version) --- p.152
Chapter V --- Introductory letter (Chinese version) --- p.153
Chapter V --- Consent form (English version) --- p.154
Chapter VI --- Consent form (Chinese version) --- p.155
Chapter VII --- Photos of the standard household measures given to children for estimation of portion size (English version) --- p.156
Chapter VIII --- Photos of the standard household measures given to children for estimation of portion size (Chinese version) --- p.157
Chapter IX --- Responses from the children to the food frequency questionnaire --- p.158
Chapter X --- The frequency of the reported food items liked or disliked by the children --- p.160

Ph.D.
It has become an accepted fact that Coronary Heart Disease is an epidemic of modern civilisation. Coronary Heart Disease is responsible for approximately a third of all deaths in the Western world (Fullard, 1990) and South Africa is no exception. Several risk factors contributing to the development of heart disease have been identified but the extent and exact nature of their contribution is not fully understood. Traditionally accepted risk factors that play a role in the development of Coronary Heart Disease include diet, hypertension, hypercholestrolaemia, smoking, physical inactivity, age, sex and genetic disposition. However the strongest combination of these factors has been unable to predict the majority of heart disease cases. In this regard psychological factors are steadily gaining acceptance as risk factors, one of the most important of these being the Type A behaviour pattern. The far reaching consequences of Coronary Heart Disease have necessitated investigations into methods of decreasing contact with risk factors, particularly psychological ones. The substantial success of the Recurrent Coronary Prevention Project (Friedman et al), coupled with the promising results from other intervention studies, suggests that behaviour change is a viable goal in the prevention of heart disease. Following on from the Recurrent Coronary Prevention Project, Venter (1993) and Viljoen (1993) adapted it for the South African population. Although relatively successful, it did have its flaws. Thus the motivation for redesigning this intervention addressing its shortcomings The revised intervention was administered to a group of 25 Coronary Heart Disease patients. A second group of 22 patients were subjected to the intervention utilised in the original South African Recurrent Coronary Prevention Project. A third group of 18 patients served as a waiting list control group. The results indicated that although the revised intervention produced larger changes in Type A behaviour than the original South African Recurrent Prevention Project intervention, these differences were not significant. Possible reasons for this were the measures utilised, the sample sizes and the nature of the groups themselves. However, the revised version of the SARCPP was found to be more effective in the reduction of the hostility and anger components of the behaviour pattern than the original version. In conclusion it was found that before any further research in this area be conducted, the measures utilised should be modified and the mechanisms of treatment effect be examined.

Objective: To determine the role of candidate gene polymorphisms in patients who sustained myocardial infarction at a young age and examine their relationship, if any, to risk factors. Since angiotensin II is known to play a pathophysiological role at the myocardial and vascular level, the genes to be studied are those regulating the renin angiotensin system and tissue metabolism. Design: The risk factors and genetic profile is described in 117 young Indians with myocardial infarction recruited over a period of thirty months (Dec 1997 - Jun 1999). Controls comprised 80 normal subjects with no clinical evidence of coronary heart disease (CHD) and with a normal effort response. The key features of this study are the selection of young subjects with myocardial infarction, (mean age 43 ± 6.8 years) in whom the possibility of a genetic basis for the disease was felt to be more likely since the confounding effect of age as a risk factor was reduced. Setting: Patients recruited 3 -12 months after myocardial infarction from Addington Hospital, Durban. This hospital subserves the Indian community in the north of Durban. The majority of patients were from the Phoenix settlement area. Results: 1. The clinical profile of the young Indian with myocardial infarction is a young man, slightly overweight with a high prevalence of risk factors, particularly smoking and diabetes, coupled with sedentary behaviour and risk-prone dietary patterns characterised by high red meat intake and low fruit and vegetable consumption, resulting in increased BMI and W/H ratios. 2. There were no differences in the patterns of gene polymorphism in the reninangiotensin system between the study and control groups. This finding extended across all candidate gene loci studied i.e. those involving aldosterone, G-protein, TGF-B and homocysteine metabolism. Serum triglycerides, haemoglobin AlC and urine microalbumin levels were elevated in the probands together with low HDL-C levels (p = 0.001). 3. A striking finding of this study was the substantial proportion of patients found to have diabetes mellitus, totalling 47% of the proband group. Of the 53 diabetic patients, (45 males and 8 females) four (3 males, 1 female) had impaired glucose tolerance. Cigarette smoking, a positive family history of hypertension/diabetes and a family history for premature CHD emerged as important risk predictors for MI. Conclusion: This study, the first to report candidate gene polymorphisms in young Indians with coronary heart disease, has shown no obvious association between the genetic loci studied and acute myocardial infarction. Instead a high prevalence of risk factors, particularly smoking and diabetes mellitus, coupled with coronary-prone behavioural patterns was observed. In the light of these findings, genome-wide screening of unaffected siblings of subjects with early onset CHD cannot be recommended in this population until common polymorphisms can be clearly identified as risk factors. Indeed this study again supports the dire need for early, school level, education in behavioural lifestyle patterns and disease predisposition. The Indian community is a very high-risk group who should be targeted, not for secondary, but for primordial disease prevention measures. The study does not rule out the role of other candidate gene polymorphisms in the pathogenesis of CHD in these subjects. The high prevalence of diabetes and insulin resistance suggests that studies of genes regulating glucose and lipid metabolism should be pursued. Such candidate genes should include genes for lipoprotein lipase and paraoxonase polymorphisms which may explain the dyslipidaemia patterns in this group.
Thesis (Ph.D.)-University of Natal, Durban, 2000.

Low physical activity levels and high serum C-reactive protein (CRP) levels are risk factors for coronary artery disease (CAD) in both men and women. However, postmenopausal women who take hormone replacement therapy (HRT) may have increased risk of CAD because of HRT-related increases in serum CRP. There are two manuscripts in this dissertation. The purpose of the first manuscript was to determine whether higher physical activity energy expenditure was associated with lower serum CRP, independent of oral HRT status and body fatness, in 133 postmenopausal women. Higher physical activity energy expenditures were significantly associated with lower serum CRP levels (r=-0.21, p=0.0l9), independent of oral HRT use, age, smoking behavior, alcohol consumption, aspirin use, and statin use. However, in the complete multivariate model, which included body fat, the association between higher physical activity and lower serum CRP levels was abolished. The purpose of the second study was to quantify the biological variability of insulin resistant CAD risk factors in a sample of 8 postmenopausal women. Risk factor outcomes, including serum total cholesterol, serum triglycerides (TG), serum high-density lipoprotein cholesterol (HDL-C), serum glucose, plasma insulin, serum CRP, waist and hip circumferences, abdominal sagittal diameter, body fat, systolic (SBP) and diastolic blood pressure, and self-reported physical activity energy expenditure, were measured on two occasions, 7-12 days apart. High absolute biological variability values (by standard error of measurement) were observed for serum TG (32.0 mg/dl), serum CRP (5.6 mg/l), SBP (4.0 mmHg), and physical activity (9.4 kcal/kg/week). High relative biological variability (by within-subjects coefficient of variation ���27.3%) was also observed for serum TG, serum CRP, and physical activity. Bland-Altman plots identified individual outliers for serum TG, serum CRP, plasma insulin, and SBP. Together, the results suggest that the correlations between lower levels of serum CRP and higher levels of physical activity, though significant, may have been attenuated by the high biological variability of both serum CRP and physical activity. Thus, the importance of higher levels of physical activity, in decreasing serum CRP and the concomitant risk of heart disease, may be underestimated in the absence of serial measurement of serum CRP and physical activity.
Graduation date: 2002

Lam Lop Chi.
Thesis submitted in: August 2005.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2006.
Includes bibliographical references (leaves 114-126).
Abstracts in English and Chinese.
Acknowledgements --- p.I
Abstract in English --- p.II-IV
Abstract in Chinese --- p.V-VI
List of Abbreviations --- p.VII-IX
List of Figures --- p.X
List of Tables --- p.XI-XII
Table of Contents --- p.XIII-XV
Chapter Chapter 1 --- Introduction
Chapter 1.1 --- Background --- p.1
Chapter 1.2 --- Risk factors --- p.6
Chapter 1.3 --- Overseas guidelines in CAD management --- p.11
Chapter 1.4 --- Angioplasty in CAD intervention --- p.15
Chapter 1.5 --- Prevention or Intervention? --- p.21
Chapter 1.6 --- Economic impact on PCI --- p.24
Chapter 1.7 --- Cost of illness --- p.28
Chapter 1.8 --- Hypothesis --- p.30
Chapter 1.9 --- Objectives --- p.30
Chapter Chapter 2 --- Cost of AMI Study
Chapter 2.1 --- Background --- p.31
Chapter 2.2 --- Objective --- p.32
Chapter 2.3 --- Method --- p.32
Chapter 2.4 --- Results --- p.35
Chapter 2.5 --- Discussion --- p.49
Chapter 2.6 --- Study limitations --- p.58
Chapter 2.7 --- Conclusions --- p.58
Chapter Chapter 3 --- Angina study
Chapter 3.1 --- Background --- p.60
Chapter 3.2 --- Objective --- p.76
Chapter 3.3 --- Hypothesis --- p.76
Chapter 3.4 --- Method --- p.76
Chapter 3.5 --- Results --- p.79
Chapter 3.6 --- Discussion --- p.93
Chapter 3.7 --- Study limitations --- p.101
Chapter 3.8 --- Conclusions --- p.101
Chapter Chapter 4 --- Overall Discussion --- p.103
Chapter Chapter 5 --- Conclusions --- p.112
References --- p.114
Appendix --- p.127

The World Health Organization (1969) has declared that heart disease is the largest plague that ever faced humanity. Myocardial Infarction (MD, in addition to causing more deaths than all other diseases of the heart combined, is responsible for changes, and in many cases deterioration, in the quality of life of survivors. Intervention programs tend to focus on preventing re-occurrence of MI. At the same time there is an urgent need for sophisticated rehabilitation programs that aim to improve quality of life after MI. It is speculated here that identification of the personality factors that relate to the different adjustment patterms of different subgroups of post-MI patients will assist in the design of an efficient rehabilitation program. Accordingly, the present study focuses on the inquiry of the psychological mechanisms that mediate between the Type A behavior pattern (TABP) and adjustment style. An integrated crisis and developmental theory based on psychoanalytical, attachment and social learning theories is proposed. The Thesis put forward is that TABP is not a homogeneous pattern and that interpersonal dependency is an underlying personality factor that subdivides Type A patients to subgroups with different developmental and adjustment patterns. It is claimed here that dependent Type A patients have a dependent-independent developmental psychodynamic conflict, and that for them, TABP is an adopted defense mechanism. They are expected to have more adjustment difficulties to the specific characteristics of the post-MI crisis than inde pendent Type A patients for whom TABP is a socially learned developmental process in an urban Western environment. Type B patients, who also lack the psychodynamic conflict, are expected to adjust as a group better than dependent Type A patients. Seventy-nine white urban South African males aged 30-60 years, after clinical MI, were tested. A combination of qualitative and quantitative methods of assessment was used in order to test the relationships between personality factors and adjustment, which was defined by multi-dimensional criteria (32 indices of adjustment) that related to various aspects of life in the post-MI period. The results confirmed the heterogeneity of TABP, dependent Type A patients adjusted less well than independent Type A patients to 16 out of 32 indices of adjustment. As expected for the same 16 indices, the behavior of Type B patients was better adjusted than dependent Type A patients. The outcomes of the adjustment of post-MI patients to all 32 indices is discussed. On the basis of the study's results and the crisis and developmental theory set out here, a differential rehabilitation program is proposed that relates to the different needs of the subgroups of post-MI patients.
Thesis (Ph.D.)-University of Natal, Durban, 1986.