A survey of 246 suggested coronary risk factors

Serum glycoproteins and severity of coronary atherosclerosis

The relation of serum glycoproteins and C-reactive protein (CRP) to severity of coronary atherosclerosis was examined in 133 men and 92 women undergoing coronary angiography. The following serum glycoproteins were determined: alpha 1-antitrypsin, alpha 1-acid glycoprotein, alpha 2-macroglobulin, ceruloplasmin, haptoglobin, fibrinogen, C4b binding protein, and lipoprotein (a) [Lp(a)]. Sex- and age-adjusted levels of alpha 1-antitrypsin, alpha 1-acid glycoproteins, alpha 2-macroglobulin, ceruloplasmin, Lp(a) and CRP were significantly associated with the severity of coronary atherosclerosis as determined by the Gensini score; these associations remained significant even after adjustment for body-mass index, smoking history, hypertension, and total cholesterol, except for Lp(a) (p = 0.075). These findings suggest that certain serum glycoproteins and CRP can serve as independent indicators for the progression of coronary atherosclerosis.

The risk epidemic in medical journals

Searches in MEDLINE databases show a rapid increase in the number of articles with the term 'risk(s)' in the title and/or abstract in the period from 1967 to 1991. This trend is found in medical journals giving a general coverage of medicine and journals covering obstetrics and gynaecology in U.S.A., Britain and Scandinavia. The most rapid increase is, however, found in epidemiological journals. Comparisons of the developments in the occurrence of such terms as risk, hazard, danger and uncertainty show that the increasing frequency of the term risk in the medical literature can not be explained as a change in terminology alone. It is hypothesized that the ongoing trend, which resembles an epidemic, is a result of developments in science and technology, that has changed our beliefs about the locus of control from factors outside human control to factors inside our control. The origins of the epidemic may be traced to the development of such disciplines as probability statistics, increased focus on risk management and health promotion, with recent developments in computer technology as the factor responsible for the escalation seen in the past decade. With the cultural selection of risks in mind, the social construction of risk is discussed. Potentially harmful effects of such an epidemic are discussed, exemplified through controversies over current epidemiological risk construction and strategies for coronary risk reduction. It is finally argued that the risk epidemic reflects the social constructions of a particular culture at a particular time in history.

Science, policy, and ethics: the case of environmental tobacco smoke

The successful campaign against smoking will long be celebrated as a landmark achievement of public health. Recently, a prominent component of this campaign has been the portrayal of environmental tobacco smoke as a major health risk. To this day, however, the scientific basis for this later contention remains speculative. The elevation of heuristic hypotheses into official precepts raises an intriguing ethical question: Should a claim of best intentions justify representing conjecture as scientific knowledge in public policy formulation?

A multifactorial approach to coronary disease risk assessment

Coronary heart disease (CHD) remains a major cause of morbidity and mortality in Western societies. Hypertension has been identified as a cardinal risk factor for CHD. Guidelines for hypertension classification and treatment are based on the results of clinical trials that have demonstrated reductions in cardiovascular endpoints in treated hypertensive patient. Controversy persists regarding the level of blood pressure at which treatment should be initiated and the desirable blood pressure goals of treatment. Several algorithms for CHD risk prediction have been developed. This report will review one recently developed approach for predicting CHD risk based upon observational data from the Framingham Heart Study. A rationale is presented for considering absolute level of CHD risk to guide hypertension treatment.

Serum lipoproteins and hemostatic function in intermittent claudication

Normoglucemic men with intermittent claudication (n = 41), mean age of 63 years, and sex-, age-, body mass index-, and smoking habit-matched controls (n = 75) were compared for plasma lipoprotein and hemostatic variables. The patients had significantly lower levels of large high-density lipoprotein (HDL) particles (HDL2b, HDL2a, and HDL3a) and elevated lipoprotein(a) [Lp(a)] concentrations than the control subjects. Of the hemostatic variables, plasminogen activator inhibitor-1 (PAI-1), plasma antiplasmin, plasma fibrinogen, and urine beta-thromboglobulin concentrations were significantly elevated in patients. In intermittent claudication patients Lp(a) correlated significantly with activation of the coagulation system, ie, with the levels of plasma fibrinogen and urine fibrinopeptide A. No correlations between the values for Lp(a) and PAI-1 or plasma alpha 2-antiplasmin were seen. The PAI-1 activity showed significant univariate correlations to the levels of HDL3b, HDL2b (inverse), and very-low-density lipoprotein triglycerides, of which the positive correlation to HDL3b persisted in multivariate analysis (r = .48, P < .001). Independent characteristics for intermittent claudication estimated by multiple regression analysis were PAI-1, plasma fibrinogen, and HDL3a, with a combined R2 of .36. The intermittent claudication subgroup that was being treated with beta-blockers/thiazides had a higher frequency of coronary heart disease compared with the other patients. In addition, the patients taking beta-blockers/thiazides had elevated triglyceride concentrations, lower HDL cholesterol with a size shift toward smaller particles, and a tendency toward raised PAI-1 and plasma alpha 2-antiplasmin levels compared with the patient group that did not take these medications.

Interaction of apolipoprotein AII with the putative high-density lipoprotein receptor

There is strong evidence to indicate that binding of HDL by cells is due to recognition of apoproteins residing on the surface of the lipoprotein by the putative HDL receptor(s). Although both of the major HDL apoproteins, AI and AII, are recognized by the putative receptor, the nature of the binding interaction and the domains of the apoproteins involved are largely unknown. Previous data from this laboratory led to the proposal of a model to explain how HDL particles containing AII interacted with the HDL receptor in a different manner as compared to HDL particles which contain apoAI but not apoAII [Vadiveloo, P. K., & Fidge, N. H. (1992) Biochem. J. 284, 145-151]. The model predicted that each chain of the apoAII homodimer contained a binding domain capable of interacting with the HDL receptor. This model was tested in the current study by preparing apoAII monomers, complexing them with phospholipid, and determining the ability of these complexes to bind to putative HDL receptors in rat liver plasma membranes (RLPM) and bovine aortic endothelial cell membranes (BAECM) by ligand blotting. The data showed that these complexes were bound by HB1 and HB2 from RLPM, and to the 110-kDa HDL binding protein from BAECM, providing critical evidence to support the model. Further investigation into the binding interaction revealed that apoAII complexed with phospholipid (apoAII-PC) bound more than delipidated apoAII, which bound more than delipidated apoAII monomers. Thus, optimum binding required the presence of lipid.(ABSTRACT TRUNCATED AT 250 WORDS)

Risk factors for atherosclerotic aortoiliac occlusive disease

Notwithstanding the difficulties in analysis because of the small number of studies available, patients with aortoiliac atherosclerosis, irrespective of their sex, have a particular "risk profile" that includes tobacco use, young age, diabetes (rare), frequent hypercholesterolemia, and limited atheroma. It must be remembered, however, that most studies have not dealt with the specific risk factors of lower limb arterial disease and the location of disease in the aortoiliac vessels. It is possible that the classical analysis of the vascular risk factors has overlooked one or more major factors such as hyperhomocysteinemia. This underscores the necessity to conduct further prospective studies specifically focused on the various aspects of lower limb and aortoiliac arterial disease in particular.

[Cardiovascular pathology and panic disorder]

The relationship between anxiety and cardiovascular function and symptoms has long been of interest, culminating in the recent emphasis on the modulation of cardiovascular response in patients with panic disorder. The relationship between panic disorder and mitral valve prolapse remains controversial. Panic disorder appears to be significantly associated with increased incidence of cardiovascular morbidity. The detection and treatment of panic disorder in patients with cardiovascular risk or diseases could have an important impact on prognosis and quality of life of the patients.

Distribution of atherosclerosis and risk factors in atherothrombotic occlusion

BACKGROUND AND PURPOSE

The present study was performed to determine the relation between distribution of atherosclerosis and risk factors in Japanese patients with atherothrombotic occlusion.

METHODS

We studied 154 patients with atherothrombotic occlusion of the extracranial internal carotid artery (n = 75, ICA group), the horizontal portion of the middle cerebral artery (n = 47, MCA group), and the basilar artery (n = 32, BA group), all of which were confirmed by cerebral angiography. We investigated the distribution of atherosclerosis of the three sites and compared the risk factors for atherosclerosis between the three groups. We used 113 subjects without stroke as the control group.

RESULTS

A strong correlation was present between atherosclerosis of the extracranial internal carotid artery and that of the basilar artery. However, only a weak correlation existed between atherosclerosis of the middle cerebral artery and that of the other vessels. Although the prevalence of smoking and hypertension was higher and high density lipoprotein cholesterol levels were lower in the three groups than in the control subjects, no significant differences were found in age, sex, prevalence of smoking and hypertension, serum levels of triglycerides, and high density lipoprotein cholesterol among the three groups. The prevalence of coronary heart disease and diabetes mellitus and the serum levels of hemoglobin A1c, total cholesterol, and low density lipoprotein cholesterol were higher in the ICA and BA groups than in the MCA group. The prevalence of electrocardiographic evidence of left ventricular hypertrophy was higher in the MCA group than in the other groups.

CONCLUSIONS

In addition to smoking, hypertension, and low concentration of high density lipoprotein cholesterol, diabetes mellitus and hypercholesterolemia seem to be associated with atherosclerosis of the extracranial internal carotid artery and the basilar artery, and advanced hypertension may play a role in the development of middle cerebral artery occlusion.

The promotion of health through planned sociopolitical change: challenges for research and policy

The focus of health promotion is moving from the level of individuals to organizations, communities and broader social policy. Traditional quantitative methods (e.g. social surveys and experimental designs) which are variously appropriate at the level of individual behavior change require adaptation and refinement when sociopolitical change becomes the mechanism for health promotion. Because of their training and experience health services researchers and health educators (especially psychologists) are understandably resistant to necessary methodologic changes. Well designed and carefully conducted qualitative studies (e.g. ethnographic interviewing, participant observation, case studies and focus group activities) are required to complement quantitative approaches, and can fill gaps where quantitative techniques are suboptimal or even inappropriate: hard qualitative techniques can support soft quantitative methods. Their utility in process evaluation is now beyond dispute. Recent work at the New England Research Institute (NERI) is used to illustrate the role of qualitative research in the evaluation of health promotion through planned sociopolitical change.

The Raymond Pearl memorial lecture, 1992: Ethnicity and disease-more than familiality

It has long been recognized that the prevalence of many, possibly most diseases differs among different ethnic groups, and it is further known that cultural differences among people affect the acceptability of measures to prevent or ameliorate a given disease process. Major public health challenges of our time are the delineation and understanding of how these differences in prevalence arise, and the fashioning of acceptable and effective intervention strategies. The web of causation is undoubtedly complex and in the unraveling there will be a need to examine new paradigms, new models of how genes and environments interact in the evolution of disease. These models must recognize the levels within the disease process where interactions can occur. This will demand a holistic rather than the reductionist approach that has obtained in the past. However, there are promising developments at the molecular and cellular levels, and the methods of data analysis grow progressively more sophisticated. This presentation briefly describes the methods of and problems confronted by genetic epidemiology in the context of studies of ethnic differences in disease. © 1993 Wiley-Liss, Inc.

Arteriosclerosis. Impairment of cellular interactions in the arterial wall

Our understanding of the cellular interactions in the arterial wall has increased considerably during the last 15 years. It has become clear that arteriosclerosis is a multifaceted disease, in which the accumulation of monocyte-derived macrophages, smooth muscle cells, T-lymphocytes, and lipid deposits contributes to the progressive thickening of the arterial intima. Many different types of stress, including cholesterol-rich lipoproteins, smoking, hypertension, hyperfibrinogenemia, endothelial damage, and inflammatory activation, contribute to this derailed "repair" response in the arterial intima. They are recognized as risk factors for cardiovascular disease. As a consequence of the progressive thickening of the arterial intima, the arterial lumen narrows, the barrier, vasoregulatory, and anticoagulant properties of the endothelium become impaired, and the arterial wall becomes prone to rupture and thrombosis. The advanced lesions can cause serious complications: myocardial infarction, stroke, claudication, and angina pectoris. As the extent of arteriosclerosis increases with age--a process that is accelerated by risk factors--it has a particular impact on the mortality and the quality of life of elderly people.

Oxidized HDL are much less cytotoxic to lymphoblastoid cells than oxidized LDL

The possible effect of oxidized HDL was investigated on lymphoblastoid cells, in comparison to the cytotoxic effect of oxidized LDL. Oxidation of HDL was promoted by UV-C irradiation, or by copper ion (5 microM) or the combination of the two treatments. HDL extensively treated by UV-C for 20 h did not exhibit any cytotoxic effect on cultured lymphoblastoid cells even at a concentration of 500 micrograms apolipoprotein A-I/ml. In contrast to UV-treated (2 h) LDL, which were highly cytotoxic (already at a concentration of 100 micrograms apolipoprotein B/ml), HDL treated by copper or copper + UV were oxidized, as shown by TBARS formation and PUFA content decrease, but were slightly cytotoxic.

Comparison of the effect of the amount and degree of unsaturation of dietary fat on plasma low density lipoproteins in vervet monkeys

The effects of the degree of unsaturation and of the amount of dietary fat on low density lipoprotein (LDL) concentration and composition were determined in vervet monkeys. Diets with fat contents of 41, 31 and 18% energy, each with a low and a high polyunsaturated to saturated fatty acid ratio (P/S; 0.27-0.38 and 1.13-1.47) were fed to six female vervet monkeys for two months. Another six females were given a low fat, high P/S diet for the same period of time, to serve as a reference. The cholesterol contents of the diets were low (21-33 mg per day) and relatively constant. LDL cholesterol concentrations decreased significantly (P < or = 0.01) when the dietary fat content decreased from 31 to 18% of energy. The dietary P/S ratio only affected LDL cholesterol concentrations during moderate (31% of energy) fat intake, where LDL cholesterol increased (P < or = 0.01) with a decrease in dietary P/S. Substantial individual variations were observed in LDL cholesterol concentration responses to dietary fat changes. The changes in LDL cholesterol concentrations were the result of changes in the concentration of LDL particles, as the molecular composition did not differ significantly between dietary periods. The high density lipoprotein cholesterol and the plasma triacylglycerol concentrations were not influenced by the dietary fat changes. During the high P/S diets, the percentage of 18:2 (linoleic acid) increased (P < or = 0.01) and that of 18:1 (oleic acid) decreased (P < or = 0.01) in LDL esterified cholesterol, as compared to the low P/S diets. In adipose tissue triacylglycerol the percentage of 18:2 was three times higher (P < or = 0.01) during the high P/S diets than during the low P/S diets.(ABSTRACT TRUNCATED AT 250 WORDS)

Confounding in epidemiological studies: why "independent" effects may not be all they seem

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Gene-environment interactions in atherosclerosis

The importance of environment and genetics working together to shape an individual's risk for atherosclerosis seems intuitively obvious. However, it is only recently that research strategies have begun to evolve that attempt to answer questions related to apportionment of risk that is due to specific environmental and genetic factors. These factors may impact upon risk either singly or, more likely, through a complex interaction that affects the metabolic history of the whole organism. Because the genetic bases of lipid and lipoprotein metabolism have been well-studied, and because of the epidemiologic and pathobiochemical associations between genetic disorders of lipid metabolism and atherosclerosis, researchers have searched for gene-environment interactions within animal and human systems in which the phenotype is defined by some index of lipoprotein metabolism. From work done in the lipoprotein area to this point a clear case can be made for: 1) the genetic influence over the phenotypic response to an environmental stimulus; 2) the environmental modulation of the phenotypic expression of severe genetic defects. In the realm of gene-environment interactions that affect lipoprotein phenotype, diet is the best-studied environmental factor.

Patients' choices and perceptions after an invitation to participate in treatment decisions

Previous search indicates that treatment outcomes may be improved if patients perceive greater control over their treatment, but the practical implications of encouraging patients to take more control have not been investigated. The present study investigated responses of 143 patients in a cardiovascular risk management clinic to an invitation to make a decision about their treatment. Subjects' choices of the target behaviour for their behaviour-change treatment were highly predictable from their state of health, reasons for coming to the clinic, what behaviours they were told they were at risk from, and contacts with health workers. The degree of control that subjects reported they had over the decision varied considerably, being negatively related to blood pressure and positively related to the degree of control that subjects believed they had over their health in general. Issues such as time-demands, the practitioner's job satisfaction, and ethical implications of patient participation are discussed.

The role of apoproteins AI and AII in binding of high-density lipoprotein3 to membranes derived from bovine aortic endothelial cells

Although binding of high-density lipoproteins (HDL) to a variety of cells in culture has been widely reported, the mechanism of this binding has yet to be fully elucidated. The aim of the current studies was to explore the roles of apoproteins (apo) AI and AII in HDL3 binding to membranes derived from bovine aortic endothelial cells. Binding studies showed that HDL3 (which contains both apo AI and apo AII) and AII-HDL3 (which contain only apo AII) bound to membranes with similar affinity (44 +/- 6 and 41 +/- 9 micrograms/ml respectively) and capacity (673 +/- 97 and 969 +/- 101 ng bound/mg of membrane protein respectively). In contrast with these results, HDL3 [AI w/o AII] (which contain apo AI, but not apo AII) bound to the membranes with a significantly higher capacity (2228 +/- 206 ng bound/mg of membrane protein) and lower affinity (65 +/- 3 micrograms/ml) as compared with HDL3 or AII-HDL3. Therefore, although both apo AI and apo AII appear capable of facilitating HDL3 binding, the mechanisms involved probably differ. A model which fits the data postulates that a common receptor exists which binds both apo AI and apo AII, and that a particle containing AII can occupy up to four receptors (partly owing to each AII molecule containing two binding domains), whereas an HDL3 [AI w/o AII] particle can occupy only one.

Concept of an antiatherosclerotic efficacy of calcium entry blockers. INTACT Investigators

Animal experiments suggest an inhibitory effect of calcium entry blockers on arterial calcinosis and the formation of atherosclerotic plaques. Experiments with isolated tissues suggest various mechanisms for an antiatherosclerotic effect of calcium entry blockers. INTACT, the International Nifedipine Trial on Antiatherosclerotic Therapy, is the first study investigating, with a prospective, placebo-controlled, randomized, double-blind design, the influence of a calcium entry blocker (nifedipine 80 mg/day) on the progression of coronary atherosclerosis in patients with proven coronary artery disease. Study endpoints were changes of established coronary stenoses (diameter reduction greater than or equal to 20%), as well as the formation of new stenoses as documented by coronary angiography. Standardized coronary angiograms were taken before and after a treatment period of 3 years. The angiograms were quantitatively analyzed with the computer-assisted edge detection system CAAS. Of the 425 patients included in the study, 282 patients (134 on nifedipine and 148 on placebo) revealed no protocol violations. In the inclusion angiograms of these patients, 893 coronary stenoses were detected which were not significantly influenced in their development by nifedipine. However, 196 entirely new coronary lesions, 185 stenoses and 11 occlusions, were found in the follow-up angiograms. There were 78 lesions in 54 patients (40%) on nifedipine (0.58 new lesions/patient) and 118 lesions in 73 patients (49%; n.s.) on placebo (0.8 new lesions/patient; p = 0.031). In two other studies on the inhibiting effect of dihydropyridine calcium entry blockers on the progression of coronary artery disease in man defining angiographic endpoints, the drugs were also shown to reduce the number of newly formed significant coronary lesions. If further trials in man confirm a protective role of calcium entry blockers against the formation of atherosclerotic coronary lesions, a new strategy in the prevention of coronary artery disease has to be considered.

Lower extremity arterial disease and the aging process: a review

Atherosclerotic disease is a major health problem in the elderly population in the U.S. To date, most research has focused on the coronary and cerebral manifestations of the disease. Lower extremity arterial disease (LEAD) has received less attention. However, the use of simple objective non-invasive diagnostic techniques in recent population-based studies has allowed identification of asymptomatic LEAD and shown that the prevalence of disease is several fold higher than previously estimated. The prevalence increases sharply with age, from 3% in those under 60 years to over 20% at 75+ years. Detection of LEAD in the elderly provides a rapid, easy assessment of the level of atherosclerosis in the body and identifies those at high risk for mortality and morbidity. LEAD is associated with a relative risk of 4 to 5 for all cause mortality. In about 25% of those with LEAD, the disease progresses over time, leading to loss of mobility, gangrene or amputation. This review summarizes current knowledge regarding the etiology and natural history of LEAD from an epidemiologic viewpoint, delineating areas in which additional research is needed.

The prevalence of homocysteinemia and hypercholesterolemia in angiographically defined coronary heart disease

Total serum homocysteine and cholesterol levels were determined in 163 male patients with typical angina who were subjected to coronary angiography. The prevalence of homocysteinemia in coronary heart disease (CHD) was 41.9%. Serum homocysteine levels were significantly elevated (p less than 0.05) in patients with major occlusion in two or three coronary arteries. Furthermore, the prevalence of homocysteinemia correlated positively (p less than 0.05) with the number of coronary vessels that were occluded. The prevalence of hypercholesterolemia was 34.9%, but, in contrast to homocysteinemia, no graded strength of association with the number of stenotic coronary arteries could be demonstrated. The results suggest that homocysteinemia may contribute significantly to the development of coronary heart disease.

Mainstream and environmental tobacco smoke

Environmental tobacco smoke (ETS) is derived from cigarette smoldering and active smoker exhalation. Its composition displays broad quantitative differences and redistributions between gas and respirable suspended particulate (RSP) phases when compared with the mainstream smoke (MSS) that smokers puff. This is because of different generation conditions and because ETS is diluted and ages vastly more than MSS. Such differences prevent a direct comparison of MSS and ETS and their biologic activities. However, even assuming similarities on an equal mass basis, ETS-RSP inhaled doses are estimated to be between 10,000- and 100,000-fold less than estimated average MSS-RSP doses for active smokers. Differences in effective gas phase doses are expected to be of similar magnitude. Thus the average person exposed to ETS would retain an annual dose analogous to the active MSS smoking of considerably less than one cigarette dispersed over a 1-year period. By contrast, consistent epidemiologic data indicate that active smoking of some 4-5 cigarettes per day may not be associated with a significantly increased risk of lung cancer. Similar indications also obtain for cardiovascular and respiratory diseases. Since average doses of ETS to nonsmoking subjects in epidemiologic studies are several thousand times less than this reported intake level, the marginal relative risks of lung cancer and other diseases attributed to ETS in some epidemiologic studies are likely to be statistical artifacts, derived from unaccounted confounders and unavoidable bias.

Low level hyperlipidemia impairs endothelium-dependent relaxation of porcine coronary arteries by two mechanisms. Functional change in endothelium and impairment of endothelium-dependent relaxation by two mediators

We evaluated the effect of a low level of hyperlipidemia and the effects of in vitro exposure to atherogenic lipoproteins (LDL, VLDL) on the vascular responsiveness of isolated porcine coronary arteries. Firstly we studied the change in vascular responsiveness induced by feeding a cholesterol-rich diet to pigs for 4 and 9 weeks (C4 and C9 pigs). The serum cholesterol level in pigs fed a cholesterol-rich diet reached 218.5 +/- 32.9 mg/dl compared with 85.5 +/- 8.4 mg/dl in the controls. Segments of the left descending coronary artery were examined. The contraction induced by KCl or prostaglandin F2 alpha was not altered significantly by hypercholesterolemia nor was the relaxation induced by the Ca2+ ionophore, A23187, or by nitroglycerin. Endothelium-dependent relaxation (EDR) evoked by high, but not low, concentrations of bradykinin was reduced in the C4 pigs as compared with those in normal animals. EDRs evoked by bradykinin, substance P, and serotonin were significantly reduced in C9 pigs. Histologically, as observed by light and electron microscopy, fatty changes or intimal thickenings were not seen in the coronary arteries of the C4 pigs. Minimal changes (intimal thickening and fragmentation of internal elastic lamina) were observed only in parts of arteries of the C9 pigs. Secondly, the direct effects of LDL and VLDL on vascular responsiveness were studied. Although preincubation with LDL inhibited the EDR caused by exposure to bradykinin and A23187 in the coronary arteries of normal and cholesterol-fed pigs, preincubation with LDL inhibited the arterial relaxation induced by exposure to substance P or serotonin in both the C4 and the C9 pigs, but not in the control animals. The degree of inhibition was especially marked in the C9 pigs. The inhibitory effect of VLDL on EDR was weaker than that of LDL. Indomethacin (5 microM) did not alter this inhibitory effect of lipoproteins. Neither LDL nor VLDL had any effect on the vascular relaxation induced by nitroglycerin. These results are consistent with the idea that endothelium-dependent arterial relaxation is attenuated even at the very early stage of cholesterol-induced atherosclerosis. Atherogenic lipoproteins may further impair the decreased EDR in the arteries of hyperlipidemic pigs by two factors: one released on stimulation with bradykinin and the calcium ionophore A23187, the other released on stimulation with substance P and serotonin.

Influence of sulfur-amino acid content variation in plant vs animal protein on serum and tissue lipids in rats

The objective of the study was to determine the effects of methionine and cysteine supplementation of soy protein isolate and casein on serum and tissue lipid levels in rats. Sixty male, weanling, Wistar-Kyoto rats were fed two sources of protein (casein or soy protein isolate) and three variations of sulfur-amino acid supplementation (none, methionine, or cysteine). At this level of protein intake (10% by weight), rats fed soy-based diets had similar serum lipid concentrations than rats fed casein-based diets. Choline was not added to the diet in order to be able to assess independent influences of methionine and cysteine on lipid metabolism. Overall, serum lipid values were greater in rats fed proteins supplemented with methionine while the addition of cysteine produced lower lipid levels. Liver lipid concentrations were increased tremendously upon cysteine supplementation of soy protein isolate. Protein quality, as determined by protein efficiency ratio, was improved by supplementation of either sulfur-amino acid; however, methionine had the greatest effect. Results indicate that the sulfur-amino acids influence lipid metabolism in the absence of dietary choline. The mechanism by which this occurs is not known.

[Risk factors for chronic non-communicable diseases: a domiciliary survey in the municipality of São Paulo, SP (Brazil). Methodology and preliminary results]

The non-communicable chronic diseases are important causes of death in Brazil, mainly in the great urban centres. There are various risk factors related to these diseases, whose remotion or attenuation would contribute to a fall in mortality. The methodology of the first comprehensive multicenter study into risk factors of non-communicable chronic diseases carried out in Latin America is explained. In Brazil, this study was carried out in the cities of S. Paulo, SP and Porto Alegre, RS. Preliminary results from the city of S. Paulo as to the prevalence of arterial hypertension (22.3%), tabagism (37.9%), obesity (18.0%), alcoholism (7.7%) and sedentarism (69.3%) are presented. These results are compared with existing data from Brazil and other countries, and the relationship between various risk factors and the mortality from cardiovascular diseases in S. Paulo and some developed countries is discussed.

High-density lipoprotein inhibits the oxidative modification of low-density lipoprotein

Oxidatively modified low-density lipoprotein (LDL), generated as a result of incubation of LDL with specific cells (e.g., endothelial cells, EC) or redox metals like copper, has been suggested to be an atherogenic form of LDL. Epidemiological evidence suggests that higher concentrations of plasma high-density lipoprotein (HDL) are protective against the disease. The effect of HDL on the generation of the oxidatively modified LDL is described in the current study. Incubation of HDL with endothelial cells, or with copper, produced much lower amounts of thiobarbituric acid-reactive products (TBARS) as compared to incubations that contained LDL at equal protein concentrations. Such incubations also did not result in an enhanced degradation of the incubated HDL by macrophages in contrast to similarly incubated LDL. On the other hand, inclusion of HDL in the incubations that contained labeled LDL had a profound inhibitory effect on the subsequent degradation of the incubated LDL by the macrophages while having no effect on the generation of TBARS or the formation of conjugated dienes. This inhibition was not due to the modification of HDL as suggested by the following findings. (A) There was no enhanced macrophage degradation of the HDL incubated with EC or copper alone, together with LDL, despite an increased generation of TBARS. (B) HDL with the lysine groups blocked (acetyl HDL, malondialdehyde (MDA) HDL) was still able to prevent the modification of LDL and (C) acetyl HDL and MDA-HDL competed poorly for the degradation of oxidatively modified LDL. It is suggested that HDL may play a protective role in atherogenesis by preventing the generation of an oxidatively modified LDL. The mechanism of action of HDL may involve exchange of lipid peroxidation products between the lipoproteins.

Post-translational modification of apolipoprotein B by transglutaminases

The major form of cross-link found in apolipoprotein B was identified as N1N12-bis-(gamma-glutamyl)spermine, a product known to be formed through the catalytic action of transglutaminases (EC 2.3.2.13). N1-(gamma-Glutamyl)spermine was present in a trace amount but epsilon-(gamma-glutamyl)lysine cross-links, which are formed during fibrin formation in plasma, were not detected. In the presence of catalytic amounts of plasma Factor XIIIa (a thrombin-dependent extracellular transglutaminase) or cellular transglutaminase (a cytosolic enzyme), apolipoprotein B and other plasma apolipoproteins (A-I, A-II and C) underwent covalently bridged polymerization and served as amine acceptor substrates. These results suggests that transglutaminases may participate in the covalent modification of apolipoproteins, either in the physiological state or during pathogenesis.

Ischemic heart disease as copper deficiency

Atherosclerosis is a complex process beginning early in life and often leading to death from ischemic heart disease in middle age. Hundreds of factors are said to contribute to this risk. More than 50 similarities between animals deficient in copper and people with ischemic heart disease have been identified. Some of the more important characteristics of this illness have been produced in experiments in which men and women were fed diets low in copper. Diets with similarly low amounts of copper are readily available to the population at large. More aspects of the anatomy, biochemistry, chemistry, epidemiology, pathogenesis and pathophysiology of ischemic heart disease can be explained by considering this illness to be a problem of copper deficiency than by considering any of several other explanations that have been offered.

Framingham study data and "established wisdom" about cigarette smoking and coronary heart disease

With the Framingham Heart Study widely recognized as the most comprehensive, sustained investigation of the precursors of coronary heart disease (CHD), an examination was made of its manifold published data on the relationship of cigarette smoking to CHD and the results were compared with the "conventional wisdom" about cigarette smoking and CHD as projected by the Surgeon General. The analysis of data in the Framingham Heart Study shows that its results are inconsistent with the Surgeon General's views about cigarette smoking and coronary heart disease. The inconsistencies refer to (1) the magnitude of the association between cigarette smoking and CHD; (2) the relative incidence of CHD in "heavy" smokers and nonsmokers; (3) the independent effect of cigarette smoking on CHD; (4) the increasing risk of developing CHD with duration of cigarette smoking; (5) the effect of smoking cessation; and (6) the association between cigarette smoking and CHD in women.