Publications by authors named "Michael T Johnstone"

Context: A common allele on chromosome 9p21 has been repeatedly associated with increased risk of coronary artery disease (CAD) in the general population. However, the magnitude of this effect in the population with diabetes has not been well characterized.

Objective: To examine the association of the 9p21 variant with CAD in individuals with type 2 diabetes and evaluate its interaction with poor glycemic control.

View Article and Find Full Text PDF

A20 or tumor necrosis factor (TNF)-induced protein 3 (TNFAIP3) is a negative regulator of nuclear factor-kappaB (NF-kappaB). We have investigated whether polymorphisms in this gene are associated with increased atherosclerosis in diabetic patients. Five tag single nucleotide polymorphisms (SNPs) were typed in 479 type 2 diabetic patients from Boston, including 239 coronary artery disease (CAD)-positive case subjects and 240 CAD-negative control subjects.

View Article and Find Full Text PDF

Adiponectin, an adipokine facilitating insulin action, has antiatherogenic effects. This study investigated whether common polymorphisms in the adiponectin receptor 1 (ADIPOR1) gene mediating these effects influence the risk of coronary artery disease (CAD) in type 2 diabetes. Linkage disequilibrium analysis of 28 single nucleotide polymorphisms (SNPs) spanning the entire ADIPOR1 locus revealed two haplotype blocks that could be tagged by six SNPs.

View Article and Find Full Text PDF

Objective: Cellular and animal studies suggest that leptin has proinflammatory and prothrombotic effects that could link increased adipose mass directly to atherogenesis. To investigate this hypothesis, we examined the effect of genetic variability at the leptin receptor (LEPR) locus on the plasma levels of fibrinogen and CRP--two markers of inflammation and susceptibility to atherosclerosis.

Methods And Results: Linkage disequilibrium analysis of 71 single-nucleotide polymorphisms (SNPs) spanning the LEPR locus revealed four haplotype blocks that could be tagged by 11 SNPs.

View Article and Find Full Text PDF

We examined the effects of high-dosage vitamin E treatment over a 12-month period on the vascular reactivity of micro- and macrocirculation and left ventricular function in diabetic patients. Subjects (n = 89) were randomized to vitamin E (1,800 IU daily) or placebo and were followed for 12 months. High-resolution ultrasound images were used to measure the flow-mediated dilation (FMD; endothelium dependent) and nitroglycerin-induced dilation (NID; endothelium independent) of the brachial artery.

View Article and Find Full Text PDF

Background: Little is known about whether direct angiotensin receptor blockade can reduce atherosclerosis and plaque disruption. This study evaluated the effect of angiotensin receptor blockade on both the development of atherosclerosis and the disruption of plaque in a modified Constantinides animal model.

Methods And Results: Twenty-eight New Zealand White rabbits underwent aortic balloon injury followed by a 1% cholesterol diet for 8 weeks.

View Article and Find Full Text PDF

CD36 is a class B scavenger receptor recognizing a variety of ligands including long-chain fatty acids and modified LDL. We investigated whether genetic variability at this locus is a determinant of free fatty acid (FFA) plasma levels and risk of coronary artery disease (CAD) in Caucasians. Typing of 21 polymorphic markers, evenly spanning the CD36 gene, revealed two linkage disequilibrium (LD) blocks that could be tagged by five polymorphisms (-33137A>G, -31118G>A, 25444G>A, 27645del>ins and 30294G>C).

View Article and Find Full Text PDF

Background: Plaque rupture with subsequent thrombosis is recognized as the underlying pathophysiology of most acute coronary syndromes and stroke. Thus, direct thrombus visualization may be beneficial for both diagnosis and guidance of therapy. We sought to test the feasibility of direct imaging of acute and subacute thrombosis using MRI together with a novel fibrin-binding gadolinium-labeled peptide, EP-1873, in an experimental animal model of plaque rupture and thrombosis.

View Article and Find Full Text PDF