Changes in estimated coronary risk in the 1980s: data from 38 populations in the WHO MONICA Project

The World Health Organization (WHO) MONICA Project is a 10-year study monitoring trends and determinants of cardiovascular disease in geographically defined populations. Data were collected from over 100 000 randomly selected participants in two risk factor surveys conducted approximately 5 years apart in 38 populations using standardized protocols. The net effects of changes in the risk factor levels were estimated using risk scores derived from longitudinal studies in the Nordic countries. The prevalence of cigarette smoking decreased among men in most populations, but the trends for women varied. The prevalence of hypertension declined in two-thirds of the populations. Changes in the prevalence of raised total cholesterol were small but highly correlated between the genders (r = 0.8). The prevalence of obesity increased in three-quarters of the populations for men and in more than half of the populations for women. In almost half of the populations there were statistically significant declines in the estimated coronary risk for both men and women, although for Beijing the risk score increased significantly for both genders. The net effect of the changes in the risk factor levels in the 1980s in most of the study populations of the WHO MONICA Project is that the rates of coronary disease are predicted to decline in the 1990s.

Velocimetry and thermometry of supersonic flow around a cylindrical body

The supersonic flow around a cylindrical body has been studied using two optical techniques. For both sets of measurements, the cylinder was mounted from the side of the tunnel, allowing investigation of the bow shock region as well as in the wake. A new technique, laser-enhanced ionization flow tagging, was used for streamwise velocity determinations behind the body. From these measurements, it was found that the downstream velocity outside the wake was (1.90 +/- 0.06) km/s, whereas inside the wake the velocity was about 0-500 m/s in the upstream direction. Planar laser induced fluorescence of nitric oxide was employed for temperature determinations. It was established that the freestream temperature was (2120 +/- 100) K, decreasing to around (1550 +/- 400) K in the wake.

Peptidergic control of gastrointestinal blood flow in the estuarine crocodile, Crocodylus porosus

Peptidergic mechanisms influencing the resistance of the gastrointestinal vascular bed of the estuarine crocodile, Crocodylus porosus, were investigated. The gut was perfused in situ via the mesenteric and the celiac arteries, and the effects of different neuropeptides were tested using bolus injections. Effects on vascular resistance were recorded as changes in inflow pressures. Peptides found in sensory neurons [substance P, neurokinin A, and calcitonin gene-related peptide (CGRP)] all caused significant relaxation of the celiac vascular bed, as did vasoactive intestinal polypeptide (VIP), another well-known vasodilator. Except for VIP, the peptides also induced transitory gut contractions. Somatostatin and neuropeptide Y (NPY), which coexist in adrenergic neurons of the C. porosus, induced vasoconstriction in the celiac vascular bed without affecting the gut motility. Galanin caused vasoconstriction and occasionally activated the gut wall. To elucidate direct effects on individual vessels, the different peptides were tested on isolated ring preparations of the mesenteric and celiac arteries. Only CGRP and VIP relaxed the epinephrine-precontracted celiac artery, whereas the effects on the mesenteric artery were variable. Somatostatin and NPY did not affect the resting tonus of these vessels, but somatostatin potentiated the epinephrine-induced contraction of the celiac artery. Immunohistochemistry revealed the existence and localization of the above-mentioned peptides in nerve fibers innervating vessels of different sizes in the gut region. These data support the hypothesis of an important role for neuropeptides in the control of the vascular bed of the gastrointestinal tract in C. porosus.

Coronary events and exposure to environmental tobacco smoke: a case-control study from Australia and New Zealand

Objectives-To estimate the relative risk of coronary heart disease (CHD) associated with exposure to environmental tobacco smoke (ETS). Design-Population-based case-control study. Subjects-Cases were 953 people identified in a population register of coronary events, and controls were 3189 participants in independent community-based risk factor prevalence surveys from the same study populations. Setting-Newcastle, Australia and Auckland, New Zealand. Main outcome measures-Acute myocardial infarction or coronary death. Results-After adjusting for the effects of age, education, history of heart disease, and body mass index, women had a statistically significant increased risk of a coronary event associated with exposure to ETS (relative risk (RR) = 1.99; 95% confidence interval (CI)= 1.40-2.81). There was little statistical evidence of increased risk found in men (RR = 1.02, 95% CI = 0.81-1.28). Conclusion-Our study found evidence for the adverse effects of exposure to ETS on risk of coronary heart disease among women, especially at home. For men the issue is unclear according to the data from our study. Additional studies with detailed information on possible confounders and adequate statistical power are needed. Most importantly, they should use methods for measuring exposure to ETS that are sufficiently accurate to permit the investigation of dose-response relationships.

Reducing coronary heart disease in the Australian Coalfields: evaluation of a 10-year community intervention

Coronary heart disease is a leading cause of death in Australia with the Coalfields district of New South Wales having one of the country's highest rates. Identification of the Coalfields epidemic in the 1970's led to the formation of a community awareness program in the late 1980's (the healthy heart support group) followed by a more intense community action program in 1990, the Coalfields Healthy Heartbeat (CHHB). CHHB is a coalition of community members, local government officers, health workers and University researchers. We evaluate the CHHB program, examining both the nature and sustainability of heart health activities undertaken, as well as trends in risk factor levels and rates of coronary events in the Coalfields in comparison with nearby local government areas. Process data reveal difficulties mobilising the community as a whole; activities had to be selected for interested subgroups such as families of heart disease patients, school children, retired people and women concerned with family nutrition and body maintenance. Outcome data show a significantly larger reduction in case fatality for Coalfields men (although nonfatal heart attacks did not decline) while changes in risk factors levels were comparable with surrounding areas. We explain positive responses to the CHHB by schools, heart attack survivors and women interested in body maintenance in terms of the meaning these subgroups find in health promotion discourses based on their embodied experiences. When faced with a threat to one's identity, health discourse suddenly becomes meaningful along with the regimens for health improvement. General public disinterest in heart health promotion is examined in the context of historical patterns of outsiders criticising the lifestyle of miners, an orientation toward communal lather than individual responsibility for health (i.e, community 'owned' emergency services and hospitals) and anger about risks from environmental hazards imposed by industrialists. (C) 1999 Elsevier Science Ltd. All rights reserved.

Rapid reduction in coronary risk for those who quit cigarette smoking

The objective of this study was to determine the rate of the decline in risk of a major coronary event after quitting cigarette smoking. It was a population-based case-control study of men and women aged 35 to 69 years in Newcastle, Australia, and men and women aged 35 to 64 years in Auckland, New Zealand, between 1986 and 1994. Cases were 5,572 people identified in population registers of coronary events and controls were 6,268 participants in independent community-based risk factor prevalence surveys from the same study populations. There was a rapid reduction in risk after quitting cigarette smoking. The risk of suffering a major coronary event for men who were current cigarette smokers was 3.5 (95% CI 3.0-4.0) times higher than the risk for never smokers but this fell to 1.5 (95% CI 1.1-1.9) for men who had quit for 1-3 years. Women who were current cigarette smokers were 4.8 (95% CI 4.0-5.9) times more likely to suffer a major coronary event than never smokers and this fell to 1.6 (95% CI 1.0-2.5) for women who had quit for 1-3 years. Those who had quit cigarette smoking for 4-6 years or more had a similar risk to never smokers. These results reinforce the importance of smoking cessation. The public health message is that the benefit of giving up smoking occurs rapidly.

Modeling the fluid-flow-induced stress and collapse in a dendritic network

An analytical approach to the stress development in the coherent dendritic network during solidification is proposed. Under the assumption that stresses are developed in the network as a result of the friction resisting shrinkage-induced interdendritic fluid flow, the model predicts the stresses in the solid. The calculations reflect the expected effects of postponed dendrite coherency, slower solidification conditions, and variations of eutectic volume fraction and shrinkage. Comparing the calculated stresses to the measured shear strength of equiaxed mushy zones shows that it is possible for the stresses to exceed the strength, thereby resulting in reorientation or collapse of the dendritic network.

Socio-economic, migrant and geographic differentials in coronary heart disease occurrence in New South Wales

Objective: This study examines the variation in coronary heart disease (CHD) mortality and acute myocardial infarction (AMI) by socio-economic status (SES), country of birth (COB) and geography (urban/rural) in the total population of New South Wales (Australia) in 1991-95. Method: CHD deaths and AMI are from complete enumerations of deaths and hospital admissions, respectively; and population denominators are from census information. Data are examined separately by sex, and comparisons of SES groups (based on municipalities), COB and region are analysed using Poisson regression, after adjustment for age. Results: The study identified higher risk for AMI admissions and CHD mortality in lower SES populations with significant linear trends, for both sexes, adjusted for age, region and COB. According to the population attributable fractions (PAF), 23-41% of the risk of CHD occurrence is due to SES lower than the highest quartile. The higher age-adjusted risk for CHD occurrence in rural and remote populations for both sexes, compared with urban communities, was lessened by adjustment for COB, and all but abolished when also adjusted for SES. COB analysis indicated significantly lower age-adjusted AMI admissions and CHD mortality compared with the Australian-born, Conclusions: Higher risks for CHD in rural populations compared with the capital city (Sydney) are due, in part, to lower SES, lesser migrant composition. Implications: Strategies for reducing CHD differentials should consider demographic factors and the fundamental need to reduce socio-economic inequalities, as well as targeting appropriate prevention measures.

Hypoxia stimulates cerebral blood flow in the estuarine crocodile (Crocodylus porosus)

The effect of N-2 respiration on cerebral blood flow (CBF) velocity on the dorsal surface of cerebellum was examined in the estuarine crocodile, Crocodylus porosus, using epi-illumination microscopy. Twelve minutes of N-2 respiration resulted in a 126% increase in CBF velocity. N-2 respiration had no effect on blood pressure, indicating an underlying cerebral vasodilation. In addition, heart rate increased significantly. Systemic injections of aminophylline and the NO synthase (NOS) inhibitor nitro-L-arginine (L-NA) did not affect the hypoxia induced increase in CBF. We conclude that C. porosus responds to hypoxia with adenosine and nitric oxide (NO) independent cerebral vasodilation, and that this is likely to be a mechanism protecting the brain from energy deficiency during prolonged dives. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.

Targeting local tissues by transdermal application: Understanding drug physicochemical properties that best exploit protein binding and blood flow effects

The targeting of topically applied drug molecules into tissues below a site of application requires an understanding of the complex interrelationships between the drug, its formulation, the barrier properties of the skin, and the physiological processes occurring below the skin that are responsible for drug clearance from the site, tissue, and/or systemic distribution and eventual elimination. There is still a certain amount of controversy over the ability of topically applied drugs to penetrate into deeper tissues by diffusion or whether this occurs by redistribution in the systemic circulation. The major focus of our work in this area has been in determining how changes in drug structure and physicochemical properties, such as protein binding and lipophilicity, affect drug clearance into the local dermal microcirculation and lymphatics, as well as subsequent distribution into deeper tissues below an application site. The present study outlines our recent thinking on the drug molecule optimal physical attributes, in terms of plasma and tissue partitioning behaviour, that offer the greatest potential for deep tissue targeting. Drug Dev. Res. 46:309-315, 1999. (C) 1999 Wiley-Liss, Inc.

A numerical study of pore-fluid, thermal and mass flow iu fluid-saturated porous rock basins

We present a numerical methodology for the study of convective pore-fluid, thermal and mass flow in fluid-saturated porous rock basins. lit particular, we investigate the occurrence and distribution pattern of temperature gradient driven convective pore-fluid flow and hydrocarbon transport in the Australian North West Shelf basin. The related numerical results have demonstrated that: (1) The finite element method combined with the progressive asymptotic approach procedure is a useful tool for dealing with temperature gradient driven pore-fluid flow and mass transport in fluid-saturated hydrothermal basins; (2) Convective pore-fluid flow generally becomes focused in more permeable layers, especially when the layers are thick enough to accommodate the appropriate convective cells; (3) Large dislocation of strata has a significant influence off the distribution patterns of convective pore;fluid flow, thermal flow and hydrocarbon transport in the North West Shelf basin; (4) As a direct consequence of the formation of convective pore-fluid cells, the hydrocarbon concentration is highly localized in the range bounded by two major faults in the basin.

Finite element analysis of flow patterns near geological lenses in hydrodynamic and hydrothermal systems

We use theoretical and numerical methods to investigate the general pore-fluid flow patterns near geological lenses in hydrodynamic and hydrothermal systems respectively. Analytical solutions have been rigorously derived for the pore-fluid velocity, stream function and excess pore-fluid pressure near a circular lens in a hydrodynamic system. These analytical solutions provide not only a better understanding of the physics behind the problem, but also a valuable benchmark solution for validating any numerical method. Since a geological lens is surrounded by a medium of large extent in nature and the finite element method is efficient at modelling only media of finite size, the determination of the size of the computational domain of a finite element model, which is often overlooked by numerical analysts, is very important in order to ensure both the efficiency of the method and the accuracy of the numerical solution obtained. To highlight this issue, we use the derived analytical solutions to deduce a rigorous mathematical formula for designing the computational domain size of a finite element model. The proposed mathematical formula has indicated that, no matter how fine the mesh or how high the order of elements, the desired accuracy of a finite element solution for pore-fluid flow near a geological lens cannot be achieved unless the size of the finite element model is determined appropriately. Once the finite element computational model has been appropriately designed and validated in a hydrodynamic system, it is used to examine general pore-fluid flow patterns near geological lenses in hydrothermal systems. Some interesting conclusions on the behaviour of geological lenses in hydrodynamic and hydrothermal systems have been reached through the analytical and numerical analyses carried out in this paper.

Changing patterns of coronary heart disease in the hunter region of New South Wales, Australia

A population-based observational study of men acid women aged 35-69 years in the Hunter Region of New South Wales, Australia, was conducted to assess the impact. of risk-factor modification and increased drug therapy on the trends in major coronary events and case fatality. From 1985 to 1993, there were 3006 coronary deaths and 6450 nonfatal major coronary events. Rates of death and nonfatal myocardial infarction declined, but there was an increase in hospital admissions for prolonged chess pain. Reductions in cigarette smoking, diastolic blood pressure, total cholesterol, and increased use of aspirin can fully explain the 3.3% (95% confidence interval [CI] 2.4, 4.2) average annual reduction in rates of major coronary events for men and the 4.1% (95% CI 2.7, 5.5) reduction for women. In contrast, increased use of aspirin, beta-blockers, fibrinolytic therapy, and angiotensin-converting enzyme inhibitors explain less than hall of the 8.9% (95% CI 5.9, 11.8) and 6.9% (95% CI 2.7, 10.9) average annual reduction in case fatality in hospital for men and women, respectively. These trends suggest a decline in severity of coronary heart disease consistent with reductions in risk-factor levels and improved acute medical treatment. J CLIN EPIDEMIOL 52;8:761-771, 1999. (C) 1999 Elsevier Science Inc.

Estimation of contribution of changes in classic risk factors to trends in coronary-event rates across the WHO MONICA Project populations

Background From the mid-1980s to mid-1990s, the WHO MONICA Project monitored coronary events and classic risk factors for coronary heart disease (CHD) in 38 populations from 21 countries. We assessed the extent to which changes in these risk factors explain the variation in the trends in coronary-event rates across the populations. Methods In men and women aged 35-64 years, non-fatal myocardial infarction and coronary deaths were registered continuously to assess trends in rates of coronary events. We carried out population surveys to estimate trends in risk factors. Trends in event rates were regressed on trends in risk score and in individual risk factors. Findings Smoking rates decreased in most male populations but trends were mixed in women; mean blood pressures and cholesterol concentrations decreased, body-mass index increased, and overall risk scores and coronary-event rates decreased. The model of trends in 10-year coronary-event rates against risk scores and single risk factors showed a poor fit, but this was improved with a 4-year time lag for coronary events. The explanatory power of the analyses was limited by imprecision of the estimates and homogeneity of trends in the study populations. Interpretation Changes in the classic risk factors seem to partly explain the variation in population trends in CHD. Residual variance is attributable to difficulties in measurement and analysis, including time lag, and to factors that were not included, such as medical interventions. The results support prevention policies based on the classic risk factors but suggest potential for prevention beyond these.