1,721,954 research outputs found
Best practice--ongoing polemics
No full textCurrent treatment strategies and disease management programs for hyperlipidemia employ a range of lipid-lowering drugs. Results from early lipid-lowering trials using diet, fibrates, niacin and other classes of drug showed that lowering plasma cholesterol can significantly reduce the risk of developing ischemic cardiovascular events. The landmark statin trials have clearly demonstrated the benefits of lipid-lowering therapy in coronary heart disease (CHD) prevention and unlike early lipid-lowering studies, a reduction in mortality may become evident with statin therapy during the first year of treatment. The number of successful lipid-intervention trials continues to increase and evidence is accumulating that lipid modification can also reduce the risk of cardiovascular events among individuals with only modest degrees of blood-lipid abnormalities. With increasingly powerful drugs to modify blood lipids, the potential levels at which to initiate treatment and the appropriate target levels are rapidly changing and debate surrounds the question of where the line to initiate treatment should be drawn. The relative lack of major adverse events with statin therapy means that the level of CHD risk at which clinical benefit occurs cannot be determined by the degree of risk at which benefit exceeds adverse events. Therefore, patients with only moderately raised cholesterol levels can be treated because statin treatment is well tolerated. One of the most important aspects of the statin trials is the finding that clinical events, such as death and disability due to coronary artery disease, may be preventable or limited in a significant number of patients if they receive aggressive therapy. Current goals for cholesterol levels in patients with established CHD are rarely achieved with non-aggressive treatment; however, with aggressive lipid lowering statins can achieve these goals in a safe and effective manner
CAROTID INTIMA MEDIA THICKNESS (IMT) AND IMT-PROGRESSION AS PREDICTORS OF VASCULAR EVENTS IN A HIGH RISK EUROPEAN POPULATION : THE IMPROVE STUDY
No full textThe intima-media thickness (IMT) of extracranial carotid arteries, assessed by ultrasound techniques, has been shown to be associated with most vascular risk factors for atherosclerosis and with the prevalence and extent of cardiovascular disease and coronary atherosclerosis. On this basis, this ultrasonic variable has been proposed as a surrogate index of atherosclerosis of other vascular regions. Studies have supported this hypothesis showing that IMT is a good predictor of new myocardial infarction and stroke. However, limited information has been provided on the relationship between IMT-progression, that is the real end point used in pharmacological studies, and cardiovascular events. Generally, attempts to delay IMT-progression using "anti-atherosclerotic" agents have provided encouraging results. However, no one of the studies so far published has been able to address, on a prospective basis, whether IMT-progression may effectively reflect the efficacy of the treatment in reducing the rate of cardiovascular events. To address these issues we designed “the IMPROVE study”, a currently on going prospective multicenter, longitudinal, long-term, observational study funded by the European community. The major objective of the IMPROVE study is to evaluate the association between IMT, IMT-progression and the rate of new vascular events in subjects at high risk of atherosclerosis. The effect of gene polymorphisms, lipid peroxidation, socio-economic and psychological variables on the same ultrasonic end points will be also evaluated. In order to achieve the project objectives, 3600 patients will be recruited in 7 European countries and followed ultrasonically and clinically for 30 months. Clinical events will be monitored up to 36 months. Data will be analysed with conventional statistics and with innovative approaches based on artificial neural networks. The study is considered as positive if a difference of at least 3% in the cumulative incidence of acute vascular events between the lowest and the highest quintiles of IMT or IMT-progression is detected. A summary of aims and design of the study will be presented
LACIDIPINE: IN VIVO EFFECTS ON INTIMAL CAROTID THICKENING IN HYPERCHOLESTEROLAEMIC RABBITS
No full textTargets for actual or potential pharmacological intervention In atherogenic processes are multiple and all aimed at causing existing lesions to regress, become stable, or progress more slowly, and also at preventing the
formation of new lesions. Until recently, in antihypertensive trials little efforts was made to evaluate either the arterial changes or the effect of drug therapy on the arterial wall. Agents such as calcium antagonists have received increasing attention as pharmacological tools with antiatherogenic potentials. The in vivo direct antiatherogenic activity of lacidipine has been investigated on carotid rabbit intimal hyperplasia induced by perivascular stimulation of one carotid artery in hypercholesterolemic normotensive rabbits by assessing
neolntimal formation. The contralateral carotid served as sham. The hypercholesterolemic diet (1.5%
cholesterol) and lacidipine (1,3,10 mg/kg), mixed with food, were given daily for 8 weeks. Six weeks after dietary and drug treatment started, intimal hyperplasia was acutely induced in one carotid artery of each rabbit as
described (Soma MR et al 1993). The drug treatment, at all doses, did not alter either rabbit blood pressure or
plasma lipid levels. The neointimal formation was followed by measuring cross-sectional thickness of intimal
(I) and medial (M) tissue of fixed arteries with light microscopy. In control animals, by 14 days after collar
placement, the process of intimal myocyte proliferation was pronounced: the arteries with no collar showed an
I/M tissue ratio of 0.03 ± 0.02, whereas In the carotids with collar the ratio was 20 fold higher (0.62 ± 0.04). The Intimal thickening was mostly cellular but abundant extracellular matrix and lipid depositions were present.
Light microscopic observation of the sham tissue confirmed that it had no intimal thickening or cholesterol
deposits. In the animals that received lacidipine neointimal formation was significantly decreased at all doses
(I/M tissue ratios were 0.47 ± 0.02, 0.40 ± 0.09 and 0.32 ± 0.02, for the 1, 3, 10 mg/kg doses, respectively).
Thus, the effect of the drug appeared to be dose-dependent, inhibiting by about 50% the intima media ratio at
higher doses. These observations suggest a direct effect of lacidipine on smooth muscle cell migration and/or
proliferation. The antiatherosclerotlc activity of lacidipine in this experimental situation is of scientific and therapeutic significance and suggests that this calcium antagonist act at an early stage of atherosclerosis. This
direct antlatherosclerotic activity of lacidipine offers new therapeutic direction for such a calcium antagonist.
Soma MR, Donetti E, Parolini C, Fumagalli R. Paoletti R. HMGCoA reductase inhibitors: in vivo effects on intimal carotid thickening in rabbits. Arteriosclerosis and Thrombosis 1993. 13(4): 563-57
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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