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Biomedical subjects

C M Ballantyne

Publications and source records attributed to C M Ballantyne.

At least 37 records · Page 2Linked to original sources
PubMed2001

A prospective study of paraoxonase gene Q/R192 polymorphism and severity, progression and regression of coronary atherosclerosis, plasma lipid levels, clinical events and response to fluvastatin.

Human serum paraoxonase (PON1) is a high-density lipoprotein (HDL)-associated enzyme that is responsible for the protective effect of HDL against oxidation of low-density lipoprotein (LDL). PON1 has a Glu to Arg polymorphism at codon 192 (CGA-->CAA) which is designated R/Q192. The R/Q192 polymorphism has been associated with coronary artery disease (CAD) in several, but not all, case-control studies. We prospectively studied the association of the Q/R192 genotypes with the severity, progression and regression of CAD, plasma lipid levels, clinical events and response to treatment with fluvastatin in a well-characterized cohort. Genotypes were determined by polymerase chain reaction (PCR) and restriction mapping with AlwI enzyme in 356 subjects in the Lipoprotein and Coronary Atherosclerosis Study (LCAS). Fasting plasma lipids were measured and quantitative coronary angiograms were obtained at baseline and 2.5 years following randomization to fluvastatin or placebo. A total of 177 (50%), 142 (40%) and 37 (10%) subjects had Q/Q, Q/R and R/R genotypes, respectively. Baseline and final plasma levels of HDL, LDL, triglyceride and other lipoproteins, lesion-specific minimum lumen diameters (MLD), mean MLD, number of coronary lesions and total occlusions at baseline and follow-up and clinical event rates were not significantly different among the genotypes. There was no genotype-treatment interaction with respect to plasma lipid levels and angiographic indices of CAD. The Q/R192 variants of PON1 are not associated with severity, progression or regression of coronary atherosclerosis, plasma lipid levels, clinical events, or response to treatment with fluvastatin. Thus, the Q/R192 polymorphism is not a major risk factor in susceptibility to CAD in the LCAS population.

Aged↗
PubMed2001

Treating mixed dyslipidemias: why and how.

Patients with only mildly elevated low-density lipoprotein cholesterol values but low high-density lipoprotein cholesterol (HDL-C) and/or high triglyceride levels are at high risk for cardiovascular disease. 3-Hydroxy-3-methyl-glutaryl-coenzyme A reductase inhibitors (also known as statins) have been shown to slow coronary heart disease (CHD) progression, reduce CHD events in patients with low HDL-C levels, and raise HDL-C concentrations in patients with mixed dyslipidemias. Some, but not all trials of fibrates have shown benefit in patients with low HDL-C levels. Combination therapy with a statin plus either a fibrate or niacin is effective in improving the entire lipid profile, but may increase cost and side effects.

Cholesterol, HDL↗
PubMed2001

Newer risk markers and surrogate endpoints in atherosclerosis management.

Risk markers that allow improved and individualized assessment of atherosclerotic disease risk and response to treatment are needed. Current candidate markers include cell adhesion molecules, such as intercellular adhesion molecule-1 and E-selectin, and inflammatory markers, such as C-reactive protein; advances in genomics and proteomics will suggest additional candidate markers. Noninvasive imaging procedures such as electron-beam computed tomography and magnetic resonance imaging also show considerable promise for monitoring disease status and response to treatment, and ultimately could provide surrogate endpoints for clinical trials of therapeutic interventions.

Biomarkers↗
PubMed2001

Efficacy and tolerability of fluvastatin extended-release delivery system: a pooled analysis.

BACKGROUND: At high doses, the pharmacokinetics of fluvastatin immediate-release (IR) are nonlinear, possibly due to saturation of hepatic uptake. Fluvastatin delivery to the liver in a slower but sustained fashion would be expected to avoid hepatic saturation without elevating systemic drug levels. OBJECTIVE: This pooled analysis compared the efficacy and tolerability of extended-release (XL) 80-mg and IR 40-mg formulations of fluvastatin in lowering low-density lipoprotein cholesterol (LDL-C) and triglyceride (TG) levels and raising high-density lipoprotein cholesterol (HDL-C) levels in patients with hypercholesterolemia. METHODS: Data were pooled from 3 double-blind, randomized, active-controlled, multicenter, parallel-group studies that compared changes in lipid and apolipoprotein levels with fluvastatin XL 80 mg at bedtime (HS) with changes in fluvastatin IR 40 mg HS or BID in patients aged > or =18 years with primary hypercholesterolemia (consistently elevated LDL-C level [> or =160 mg/dL] and plasma TG levels < or =400 mg/dL). The primary efficacy variable was percent change in LDL-C from baseline. RESULTS: The pooled analysis provided an intent-to-treat efficacy study population of 1674 patients. At 4 weeks, fluvastatin XL 80 mg HS reduced LDL-C levels by a mean of 36.3% (median 38%), significantly greater than a mean reduction of 25.9% (median 27%) seen with fluvastatin IR 40 mg HS, and an incremental additional mean reduction in LDL-C of 10.4% (P < 0.001). At 4 and 24 weeks, fluvastatin XL 80 mg HS provided an LDL-C reduction equivalent to fluvastatin IR 40 mg BID (P < 0.001 for noninferiority). Significant, dose-related changes in HDL-C, LDL-C:HDL-C ratio, total cholesterol, TG, and apolipoprotein A-I and apolipoprotein B levels also occurred. Mean HDL-C level increased by 8.7% and median TG level decreased by 19% with fluvastatin XL 80 mg HS (P < 0.001 and P < 0.05 vs fluvastatin IR 40 mg HS, respectively). Maximum mean increases in HDL-C level (21%) and median decreases in TG level (31%) with fluvastatin XL 80 mg HS occurred in patients with type IIb dyslipidemia and the highest baseline TG. Adverse events were mild, with similar frequency in all treatment groups. CONCLUSIONS: Once-daily administration of fluvastatin XL 80 mg provides enhanced efficacy with an additional 10.4% reduction in LDL-C levels compared with fluvastatin IR 40 mg HS, and superior increases in HDL-C levels, particularly in patients with elevated TG levels (P < 0.05 vs fluvastatin IR 40 mg HS). Fluvastatin XL 80 mg HS has a good tolerability profile and is effective as starting and maintenance lipid-lowering treatment in patients with type II hypercholesterolemia.

Adult↗
PubMed2001

The evolving role of high-density lipoprotein in reducing cardiovascular risk.

In many patients with coronary artery disease, a low level of high-density lipoprotein cholesterol (HDL-C), rather than substantially elevated low-density lipoprotein cholesterol (LDL-C), is often the predominant lipid abnormality. Although the National Cholesterol Education Program treatment guidelines include HDL-C concentration as a major risk factor for primary prevention, the guidelines' emphasis on LDL-C as the primary target of therapy may cause uncertainty as to whether risk reduction strategies should focus on lowering LDL-C or raising HDL-C in high-risk patients with low HDL-C. Recent clinical trial evidence and epidemiologic data suggest that HDL-C should play a more important role in risk assessment, and that the definition of low HDL-C may need adjustment from the current National Cholesterol Education Program definition of <35 mg/dL to perhaps <40 mg/dL in men and <45 mg/dL in women. Patients with low HDL-C should receive aggressive risk factor modification, and more emphasis on increasing HDL-C may be warranted in addition to lowering LDL-C. (c) 2001 by CHF, Inc.

Journal Article↗
PubMed2001

Leukocyte trafficking and myocardial reperfusion injury in ICAM-1/P-selectin-knockout mice.

P-selectin and intercellular adhesion molecule-1 (ICAM-1) mediate early interaction and adhesion of neutrophils to coronary endothelial cells and myocytes after myocardial ischemia and reperfusion. In the present study, we examined the physiological consequences of genetic deletions of ICAM-1 and P-selectin in mice. In wild-type mice, after 1 h of ischemia followed by reperfusion, neutrophil influx into the area of ischemia was increased by 3 h with a peak at 24 h and a decline by 72 h. ICAM-1/P-selectin-deficient mice showed a significant reduction in neutrophils by immunohistochemistry or by myeloperoxidase activity at 24 h but no significant difference at 3 h. Infarct size (area of necrosis/area at risk) assessed 24 h after reperfusion was not different between wild-type and deficient mice after 30 min and 1 h of occlusion. Mice with a deficiency in both ICAM-1 and P-selectin have impaired neutrophil trafficking without a difference in infarct size due to myocardial ischemia-reperfusion.

Animals↗
PubMed2001

Surrogate endpoints and newer risk markers in atherosclerosis management.

Trials with clinical events as the primary endpoint inherently have poor sensitivity to detect therapeutic effects on plaque stabilization and thrombosis because most plaques that rupture do not cause symptoms. Blood tests or imaging modalities that correlate to the burden or activity of atherosclerosis may provide surrogate endpoints to assess therapeutic efficacy in both clinical trials and clinical practice. For surrogate endpoints to be valid in clinical trials, they must be biologically plausible (i.e., related to the disease process) and altered by therapies that decrease the endpoint for which they are used as a substitute. Examples of surrogate endpoints include progression of coronary disease assessed by angiography, intravascular ultrasound, and other imaging techniques. Risk assessment may be refined and therapy better monitored with blood tests that measure novel markers of atherosclerotic disease. Markers that have been shown to be associated with atherosclerosis include C-reactive protein, intercellular adhesion molecule 1, interleukin-6, and fibrinogen.

Arteriosclerosis↗
PubMed2000

Apolipoprotein E genotypes and response of plasma lipids and progression-regression of coronary atherosclerosis to lipid-lowering drug therapy.

OBJECTIVES: We sought to examine the association of apolipoprotein (apo) E genotypes with baseline plasma lipid levels and severity of coronary artery disease (CAD), as well as the response to treatment with fluvastatin in the Lipoprotein and Coronary Atherosclerosis Study (LCAS). BACKGROUND: Apo E genotypes have been associated with plasma lipid levels and CAD. However, the influence of apo E genotypes on the response of plasma lipids and CAD progression or regression to statin treatment in patients with mildly to moderately elevated cholesterol remains unknown. METHODS: Apo E genotypes were determined by polymerase chain reaction and restriction mapping. Plasma lipids were measured at baseline and 12 weeks after therapy with fluvastatin or placebo in 320 subjects. In 287 subjects, quantitative coronary angiography was performed at baseline and after 2.5 years of treatment. RESULTS: Subjects with the 3/3 genotype had greater reductions in total cholesterol (20.4% vs. 15.4%, p = 0.01) and low density lipoprotein (LDL) cholesterol (28.8% vs. 22.7%, p = 0.03) than did the subjects with the 3/4 or 4/4 genotype. In contrast, subjects with the 2/3 genotype (n = 10) had a greater increase in high density lipoprotein cholesterol (19.1%) than did the subjects with the 3/3 genotype (4.3%, p = 0.002) and those with the 3/4 or 4/4 genotype (7.0%, p = 0.02). Subjects with the 3/4 or 4/4 genotype had an increased frequency of previous angioplasty, but other measures of baseline CAD severity and baseline lipids did not differ significantly among the genotypes, nor did CAD progression or clinical events. CONCLUSIONS: Although subjects with the epsilon4 allele had less reduction in LDL cholesterol with fluvastatin, they had similar benefit in terms of CAD progression.

Anticholesteremic Agents↗
PubMed2000

Efficacy and safety of an extended-release formulation of fluvastatin for once-daily treatment of primary hypercholesterolemia.

An extended-release (ER) formulation of fluvastatin 80 mg has been developed for once-daily treatment of primary hypercholesterolemia in patients who require fluvastatin dosages of > 40 mg/day. The study aimed to determine the efficacy and safety of the new formulation and to assess the dose response over the range of 40 to 160 mg/day. After a 4-week placebo/dietary run-in period, 123 patients with primary hypercholesterolemia (Fredrickson type IIa/IIb) were randomized to receive fluvastatin 40, 80, or 160 mg/day for 6 weeks. The 40 mg/day dosage was administered as the marketed immediate-release (IR) capsule and the 80 mg/day dosage as 1 80-mg ER tablet. Patients receiving 160 mg/day were administered 80 mg/day (1 ER tablet) for the first 2 weeks, followed by 160 mg/day (2 ER tablets) for the remainder of the study. All doses were administered once daily at bedtime. The results showed a linear dose-response relation. Doubling the fluvastatin dosage resulted in a 6% greater mean percent reduction in low-density lipoprotein cholesterol (40 mg IR -29%; 80 mg ER -35%; 160 mg ER -41%). In the 160-mg ER group, 62% of patients achieved > or = 40% reductions in low-density lipoprotein cholesterol compared with 32% and 10% of patients in the 80-mg ER and 40-mg IR groups, respectively. Dose ordering of the response was also observed for the other lipid parameters. Fluvastatin ER was well tolerated. Thus, the new ER formulation of fluvastatin was effective and well tolerated in the once-daily treatment of primary hypercholesterolemia.

Adult↗
PubMed2000

IL-10 is induced in the reperfused myocardium and may modulate the reaction to injury.

Reperfusion of the ischemic myocardium is associated with a dramatic inflammatory response leading to TNF-alpha release, IL-6 induction, and subsequent neutrophil-mediated cytotoxic injury. Because inflammation is also an important factor in cardiac repair, we hypothesized the presence of components of the inflammatory reaction with a possible role in suppressing acute injury. Thus, we investigated the role of IL-10, an anti-inflammatory cytokine capable of modulating extracellular matrix biosynthesis, following an experimental canine myocardial infarction. Using our canine model of myocardial ischemia and reperfusion, we demonstrated significant up-regulation of IL-10 mRNA and protein in the ischemic and reperfused myocardium. IL-10 expression was first detected at 5 h and peaked following 96-120 h of reperfusion. In contrast, IL-4 and IL-13, also associated with suppression of acute inflammation and macrophage deactivation, were not expressed. In the ischemic canine heart, CD5-positive lymphocytes were the predominant source of IL-10 in the myocardial infarct. In the absence of reperfusion, no significant induction of IL-10 mRNA was noted. In addition, IL-12, a Th1-related cytokine associated with macrophage activation, was not detected in the ischemic myocardium. In vitro experiments demonstrated late postischemic cardiac-lymph-induced tissue inhibitor of metalloproteinases (TIMP)-1 mRNA expression in isolated canine mononuclear cells. This effect was inhibited when the incubation contained a neutralizing Ab to IL-10. Our findings suggest that lymphocytes infiltrating the ischemic and reperfused myocardium express IL-10 and may have a significant role in healing by modulating mononuclear cell phenotype and inducing TIMP-1 expression.

Adjuvants, Immunologic↗
PubMed2000

Platelet glycoprotein ibalpha is a counterreceptor for the leukocyte integrin Mac-1 (CD11b/CD18).

The firm adhesion and transplatelet migration of leukocytes on vascular thrombus are both dependent on the interaction of the leukocyte integrin, Mac-1, and a heretofore unknown platelet counterreceptor. Here, we identify the platelet counterreceptor as glycoprotein (GP) Ibalpha, a component of the GP Ib-IX-V complex, the platelet von Willebrand factor (vWf) receptor. THP-1 monocytic cells and transfected cells that express Mac-1 adhered to GP Ibalpha-coated wells. Inhibition studies with monoclonal antibodies or receptor ligands showed that the interaction involves the Mac-1 I domain (homologous to the vWf A1 domain), and the GP Ibalpha leucine-rich repeat and COOH-terminal flanking regions. The specificity of the interaction was confirmed by the finding that neutrophils from wild-type mice, but not from Mac-1-deficient mice, bound to purified GP Ibalpha and to adherent platelets, the latter adhesion being inhibited by pretreatment of the platelets with mocarhagin, a protease that specifically cleaves GP Ibalpha. Finally, immobilized GP Ibalpha supported the rolling and firm adhesion of THP-1 cells under conditions of flow. These observations provide a molecular target for disrupting leukocyte-platelet complexes that promote vascular inflammation in thrombosis, atherosclerosis, and angioplasty-related restenosis.

Animals↗
PubMed2000

Impact of evidence-based "clinical judgment" on the number of American adults requiring lipid-lowering therapy based on updated NHANES III data. National Health and Nutrition Examination Survey.

BACKGROUND: When the National Cholesterol Education Program Adult Treatment Panel II (ATP II) guidelines were published, National Health and Nutrition Examination Survey III data for 1988 to 1991 were used to estimate the number of Americans requiring lipid-lowering therapy based on ATP II cut points. However, the guidelines recommend using clinical judgment to determine whether to initiate drug therapy in individuals whose low-density lipoprotein cholesterol levels remain above treatment goals with diet therapy but below the initiation level for drug therapy. METHODS: We analyzed updated (1988-1994) National Health and Nutrition Examination Survey III data, based on a sample of 6796 adults aged 20 years and older, to estimate the numbers of American adults with an elevated low-density lipoprotein cholesterol level and requiring drug therapy using cut points vs clinical judgment as specified in ATP II guidelines. RESULTS: Assuming a 10% low-density lipoprotein cholesterol reduction with diet, an estimated 10.4 million American adults require drug therapy based on ATP II cut points. If we include individuals for whom the guidelines recommend clinical judgment, the estimate increases to 28.4 million. The largest increase occurs in individuals without known coronary heart disease but with 2 or more risk factors: from 5.5 to 17.5 million. These high-risk individuals have low-density lipoprotein cholesterol concentrations similar to those in patients with coronary heart disease. CONCLUSIONS: Since the ATP II guidelines were published, clinical judgment has been informed by abundant clinical trial evidence establishing the safety and benefit of lipid-lowering therapy. The large number of individuals at high risk for coronary heart disease emphasizes the need for cost-effective therapy to extend treatment to the greatest number of individuals who may benefit.

Adult↗
PubMed2000

A variant of p22(phox), involved in generation of reactive oxygen species in the vessel wall, is associated with progression of coronary atherosclerosis.

A series of pro-oxidant and antioxidant enzymes, such as the NADPH oxidase system, maintain the redox state in the vessel wall. A major component of NADPH oxidase is p22(phox), which is implicated in atherosclerosis. We prospectively studied the association of the histidine (H)(72)-->tyrosine (Y) mutation in p22(phox) with the severity and progression/regression of coronary artery disease (CAD), plasma lipid levels, clinical events, and response to treatment with fluvastatin in a well-characterized population. Genotypes were determined by polymerase chain reaction and restriction digestion with RsaI enzyme in 368 subjects in the Lipoprotein and Coronary Atherosclerosis Study (LCAS). Fasting plasma lipids and quantitative coronary angiograms were obtained at baseline and 2.5 years after randomization to fluvastatin or placebo. Subjects with CC genotype (n=157) were identified by the presence of 396-bp and 113-bp products on gel electrophoresis. Those with TT (n=39) were identified by the presence of 316-bp, 113-bp, and 80-bp products, and those with CT (n=172) by the presence of 396-bp, 316-bp, 113-bp, and 80-bp products. Baseline and final plasma levels of lipids and the baseline severity of CAD were not significantly different among the genotypes. In the placebo group, subjects with the mutation had a 3- to 5-fold greater loss in mean minimum lumen diameter (MLD) (TT: -0.15+/-0.15; CT: -0.17+/-0.26; and CC: -0.03+/-0.22 mm; P=0. 006) and lesion-specific MLD (TT: -0.15+/-0.06; CT: -0.18+/-0.03; and CC: -0.06+/-0.03 mm; P=0.038) than those without. Progression was also more (TT: 8/17 [47%]; CT: 35/73 [48%]; and CC: 17/62 [27%]) and regression less (TT: 0/17 [0%]; CT: 1/73 [1%]; and CC: 11/72 [18%]) common in those with the mutation (P=0.002). The C(242)T mutation in p22(phox), involved in maintaining the redox state in the vessel wall, is associated with progression of coronary atherosclerosis in the LCAS population.

Adult↗
PubMed2000

Strategies for implementing lipid-lowering therapy: pharmacy-based approach.

A multidisciplinary program was designed to improve patient outcomes after an acute coronary event. The primary objective of the program was that lipid-lowering therapy be prescribed at the time of discharge for acute myocardial infarction (AMI) and percutaneous transluminal coronary angioplasty (PTCA) patients. Secondary objectives for this program were (1) a baseline lipid panel within the first 24 hours of admission and (2) documentation of discharge counseling for lipid-lowering therapy in the patient medical record. Improvements were reported for all 3 objectives. For the primary indicator, lipid-lowering therapy prescribed at discharge, the baseline value increased from 40% to 72-81%. The percentage of patients with a lipid panel within 24 hours of admission improved from a baseline of 13% to 38-71%. Overall, 28-77% of patient records contained documentation of lipid-lowering medication counseling after initiation of the program. This information should provide the necessary benchmarking data to maintain competitiveness in the dynamic healthcare environment. Overall, this program provides high-quality, cost-effective health care for the patient with established coronary artery disease.

Angioplasty, Balloon, Coronary↗
PubMed2000

Quality assessment and lipid management: considerations for computer databases for tracking patients.

Improving the quality of lipid management requires an objective assessment of current practice and the ability to monitor whether quality is improved by implementing changes in practice. In a competitive healthcare environment, documentation of quality of care and patient outcomes may be important in securing contracts. It would be almost impossible to perform a meaningful clinical-outcome analysis in a timely fashion without the support of a computerized database. However, evaluating, selecting, and implementing computerized databases can be a daunting task. Before the purchase of a database, the following steps should be performed: (1) consider and prioritize the goals for the computerized database; (2) audit charts to determine whether the existing chart format meets the current guidelines for reimbursement and medical-legal standards; (3) revise the paper chart to improve fulfillment of the goals from step 1; (4) consider the specific clinical environment, including the skill level of personnel using the system, how user-friendly the system is, whether the system is multifunctional, and the costs associated with the software and implementation. We have evaluated 3 types of computerized databases and report their strengths and weaknesses; we also briefly discuss the electronic medical record.

Continuity of Patient Care↗
PubMed2000

A prospective study of genetic markers of susceptibility to infection and inflammation, and the severity, progression, and regression of coronary atherosclerosis and its response to therapy.

Inflammation plays a key role in susceptibility to coronary atherosclerosis and response to therapy. A diverse array of factors modulates inflammation, including interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), and CD14 receptors on the surface of macrophages. Genes encoding for inflammatory markers have variants that regulate their expression and are potential risk factors for atherosclerosis. We prospectively analyzed the possible association of CD14 -260C/T, TNF-alpha -308G/A, and IL-6 -174G/C variants, located in the promoter regions, with the severity, progression, and response to therapy of coronary atherosclerosis in a well-characterized cohort. We studied 375 subjects enrolled in the Lipoprotein and Coronary Atherosclerosis Study (LCAS). Genotypes were determined by polymerase chain reaction (PCR) and restriction mapping. Fasting plasma lipids and quantitative coronary angiograms were obtained at baseline and 2.5 years following randomization to fluvastatin or placebo. Distributions of genotypes were--for CD14: 100 CC, 184 CT, and 86 TT; IL-6: 152 GG, 153 GC, and 62 CC; and TNF-alpha: 244 GG, 110 GA, and 17 AA. The CD14 CC genotype was associated with incidence of new coronary occlusion (P=0.026); TNF-alpha AA genotype with history of myocardial infarction (MI, P=0.04), and A allele with total occlusions at baseline (P=0.027), and systolic blood pressure (P=0.046); and IL-6-174 CC genotype with baseline minimum lumen diameter (P=0.043) and reduction in lipoprotein(a) with fluvastatin (P=0.03). Otherwise, no association between the genotypes and the biochemical, angiographic, and clinical phenotypes was detected, and neither were genotype-treatment interactions. Functional variants of CD14 -260C/T, TNF-alpha -308G/A, and IL-6 -174G/C, implicated in the susceptibility to infection, are unlikely to confer major risk for susceptibility to coronary atherosclerosis and its progression or response to therapy in the LCAS population.

Adult↗