PubMed Health⌕ Search

Biomedical subjects

George Steiner

Publications and source records attributed to George Steiner.

17 recordsLinked to original sources
PubMed2006

Statement of the problem.

The Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) study poses 2 questions. Of the options in treating the hyperglycemia of type 2 diabetes mellitus, which, if either, would be best for decreasing the likelihood of death or a serious cardiovascular disease event such as a heart attack: correcting the relative insulin deficiency or reducing insulin resistance? Do individuals with diabetes whose coronary disease can be managed medically have a better outcome with initial medical or interventional (percutaneous intervention or coronary artery bypass grafting) treatment? This article outlines the reasons for asking these questions.

Angioplasty, Balloon, Coronary↗
PubMed2005

Fibrates and coronary risk reduction.

Many medications are currently available to correct lipoprotein abnormalities when lifestyle measures alone are not sufficient. No single agent or class of agents is able to correct all of the lipoprotein abnormalities. This paper reviews the role of one class, the fibrates, in the management of lipid disorders and summarizes the clinical trial information relating to their impact on coronary artery disease.

Cholinergic Antagonists↗
PubMed2005

Fenofibrate reduces progression to microalbuminuria over 3 years in a placebo-controlled study in type 2 diabetes: results from the Diabetes Atherosclerosis Intervention Study (DAIS).

BACKGROUND: Microalbuminuria is an early marker of diabetic nephropathy and an independent risk factor for cardiovascular disease. In the Diabetes Atherosclerosis Intervention Study (DAIS), treatment of people with type 2 diabetes with micronized fenofibrate for an average of 38 months reduced the progression of angiographically evaluated coronary artery disease and improved lipoprotein level abnormalities compared with placebo. The aim of this analysis is to study the influence of the treatment on changes in urinary albumin excretion. METHODS: Microalbuminuria was measured on 2 to 3 occasions by using timed overnight samples at baseline and yearly thereafter in 314 DAIS participants (77 women, 237 men; average age, 56 years); all except 3 participants had either a normal albumin excretion rate (<20 microg/min; n = 214) or microalbuminuria (albumin, 20 to 200 microg/min; n = 97) before randomization. Tabulated shifts (between normal, microalbuminuria, and macroalbuminuria) from baseline to last observed values were compared between treatment groups by means of chi-square or Fisher's exact test. RESULTS: Fenofibrate significantly reduced the worsening of albumin excretion (fenofibrate, 8% versus placebo, 18%; P < 0.05). This effect was caused mostly by reduced progression from normal albumin excretion to microalbuminuria: 3 of 101 participants in the fenofibrate group versus 20 of 113 participants in the placebo group (P < 0.001). Overall, changes in albumin excretion were independent of age or changes in lipid or creatinine levels, weight, or blood pressure. CONCLUSION: Improvement in lipid profiles with fenofibrate in patients with type 2 diabetes was associated with reduced progression from normal albumin excretion to microalbuminuria.

Albuminuria↗
PubMed2005

A new perspective in the treatment of dyslipidemia : can fenofibrate offer unique benefits in the treatment of type 2 diabetes mellitus?

Patients with diabetes mellitus are at higher risk for cardiovascular events than those without diabetes. Furthermore, patients with diabetes have a characteristic 'lipid triad' of low high-density lipoprotein-cholesterol (HDL-C) levels, high triglyceride levels, and normal or slightly raised low-density lipoprotein-cholesterol (LDL-C) levels, with a preponderance of small, dense LDL-C particles. Current guidelines on preventing cardiovascular disease recognize the need not only to reduce LDL-C levels, but also to increase HDL-C and decrease triglyceride levels in diabetic patients. Some clinical trials of HMG-CoA reductase inhibitors (statins) have included large populations of diabetic patients. In some of these trials (such as 4S [Scandinavian Simvastatin Survival Study], CARE [Cholesterol and Recurrent Events] trial, and the HPS [Heart Protection Study]), HMG-CoA reductase inhibitor treatment significantly reduced cardiovascular events in diabetic patients, whereas in other trials (ALLHAT-LLT [Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial], ASCOT [Anglo-Scandinavian Cardiac Outcomes Trial]) the reductions were not significant. In CARDS (Collaborative Atorvastatin Diabetes Study), the first large HMG-CoA reductase inhibitor study to enroll only patients with type 2 diabetes, atorvastatin reduced cardiovascular events by 37% (p=0.001) compared with placebo. Fibric acid derivatives (fibrates), which are agonists of peroxisome proliferator-activated alpha receptors, exert their effects by altering the transcription of genes encoding proteins that control lipoprotein metabolism. Fibric acid derivatives are a valuable tool in the treatment of dyslipidemia in patients with diabetes, as they reduce plasma triglyceride levels by 30--50%, increase HDL-C levels by 10--15%, and shift the distribution of LDL subfractions towards larger, less atherogenic particles. The DAIS (Diabetes Atherosclerosis Intervention Study), which was conducted exclusively in patients with type 2 diabetes, found that fenofibrate reduces the progression of angiographic coronary artery disease. The VA-HIT (Veterans Affairs Cooperative Studies Program HDL-C Intervention Trial) showed that gemfibrozil reduced cardiovascular events in subgroups of diabetic patients. A large clinical event study, FIELD (Fenofibrate Intervention and Event Lowering in Diabetes), which is currently being completed, will provide further information on the value of fenofibrate for the reduction of cardiovascular risk in patients with diabetes.

Diabetes Mellitus, Type 2↗
PubMed2004

Effect of fenofibrate-mediated increase in plasma homocysteine on the progression of coronary artery disease in type 2 diabetes mellitus.

The Diabetes Atherosclerosis Intervention Study (DAIS) examined the effects of fenofibrate or placebo on the progression of coronary artery disease (CAD) in 418 type 2 diabetic subjects with dyslipidemia. Fenofibrate use was associated with a 6% increase in high-density lipoprotein cholesterol, a 28% decrease in triglycerides, a 5% decrease in low-density lipoprotein cholesterol, and a 55% increase in plasma homocysteine (tHcy). The purpose of the present study was to determine whether this increase in tHcy in the fenofibrate group was associated with CAD progression or with clinical events. The increase in tHcy with fenofibrate (n = 207) was not related to changes in factors known to modulate tHcy levels (serum levels of Vitamin B(12), folate, or renal function). CAD was quantified by angiography at baseline and after a minimum of 3 years of therapy with fenofibrate or placebo. The primary end point was change in mean segment diameter (MSD), minimal lumen diameter, and percent stenosis. Baseline tHcy level was correlated with percent diameter stenosis (r = 0.111, p = 0.028). Baseline, but not end-of-study elevated tHcy levels, decreased the beneficial effect of fenofibrate. Unexpectedly, the final tHcy levels correlated negatively with CAD progression (r = -0.111, p = 0.031) in the overall group. In the fenofibrate group, there was no significant correlation between tHcy and minimal lumen diameter (r = -0.135, p = 0.069), or percent stenosis. An increase in tHcy levels was not correlated with adverse clinical events in the fenofibrate group. This analysis of the the DAIS reveals that the fenofibrate-mediated increase in tHcy levels does not attenuate the beneficial effects of fenofibrate on CAD progression or clinical events.

Aged↗
PubMed2004

Increased apoC-III production is a characteristic feature of patients with hypertriglyceridemia.

Apolipoprotein (apo) C-III plays an important role in regulating plasma triglyceride (TG) metabolism. In order to further investigate the plasma metabolism of apoC-III in hypertriglyceridemic subjects, we have studied the plasma kinetics of VLDL apoC-III, HDL apoC-III and total plasma apoC-III with a primed constant intravenous infusion of deuterated leucine in a group of male patients with mixed hyperlipidemia (type IIb hyperlipoproteinemia, HLP, n=6) and in a group with type III HLP (n=6). Compared to normolipidemic control subjects (n=5), patients with type IIb and type III HLP had significantly higher levels of plasma TG (0.89 +/- 0.15 mmol/l vs 2.56 +/- 0.40 mmol/l vs 8.76 +/- 1.39 mmol/l, respectively, P <0.01), plasma apoC-III (9.5 +/- 0.8 mg/dl vs 20.8 +/- 2.5 mg/dl vs 41.7 +/- 5.6 mg/dl, P <0.01) and VLDL apoC-III (3.6 +/- 0.8 mg/dl vs 14.6 +/- 2.2 mg/dl vs 35.4 +/- 5.1 mg/dl, P <0.01). VLDL apoC-III production rates were significantly elevated in type IIb and type III patients (1.35 +/- 0.23 mg kg(-1) day(-1) vs 3.53 +/- 0.43 mg kg(-1) day(-1) vs 5.60 +/- 0.78 mg kg(-1) day(-1), P <0.01), as were total plasma apoC-III production rates (1.80 +/- 0.22 mg kg(-1) day(-1) vs 4.16 +/- 0.44 mg kg(-1) day(-1) vs 7.26 +/- 0.74 mg kg(-1) day(-1), P <0.01). VLDL apoC-III but not total plasma apoC-III fractional catabolic rates were reduced in type IIb and type III patients. Together with our previous results showing an increase of apoC-III production in patients with type IV HLP, and in overweight subjects with reduced insulin sensitivity, our data suggest that increased apoC-III production is a characteristic feature of patients with hypertriglyceridemia.

Adult↗
PubMed2004

Fibrates in the metabolic syndrome and in diabetes.

There is increasing evidence that fibrates can reduce coronary artery disease. This finding seems to be particularly the case inpatients with the metabolic syndrome or with diabetes. Their beneficial effects can be explained partly by their effects on lipoproteins,but these effects may also result from some of their nonlipid pleotropic effects. Clinical trials are still needed to determine the potential role played by such pleotropic actions.

Cholinergic Antagonists↗
PubMed2004

Response to micronized fenofibrate treatment is associated with the peroxisome-proliferator-activated receptors alpha G/C intron7 polymorphism in subjects with type 2 diabetes.

OBJECTIVE: The association between polymorphisms in candidate genes related to lipoprotein metabolism and the reduction in plasma triglyceride (TG) in response to fenofibrate treatment was evaluated in subjects with type 2 diabetes treated with micronized fenofibrate (200 mg/day) for at least 3 years in the Diabetes Atherosclerosis Intervention Study. METHODS: The cholesteryl ester transfer protein Taq1B, LPL S447X, hepatic lipase -514 C-->T, peroxisome-proliferator-activated receptors alpha (PPARA) L162V and G/C intron 7 polymorphisms and the apolipoprotein E2/E3/E4 alleles were genotyped using PCR and restriction enzyme digestion. Subjects were divided into high TG-responders (with > 30% TG relative reduction after treatment) and low TG-responders. RESULTS: The frequency of the PPARA intron 7 G/G genotype was higher in high TG-responders than in low TG-responders (85% vs. 69%, P < 0.05). There was no significant difference between the percentage of high TG-responders and low TG-responders for any of the other genetic polymorphisms examined. In stepwise logistic regression, baseline TG and only the PPARA intron 7 polymorphism among the others were selected in the model as significant predictors of TG-response (odds ratio: 3.10, 95% CI: 1.28-7.52, P = 0.012 for PPARA polymorphism). With age, gender, body mass index, smoking status and HbA1c as additional factors, baseline TG (P< 0.0001), intron 7 (P = 0.013), body mass index (P = 0.040) and LPL-S447X (P = 0.084) were significant predictors of TG-response. CONCLUSION: These results indicate that elevated baseline TG levels and PPARA gene intron 7 G/G genotype were associated with TG reduction > 30% after fenofibrate treatment in patients with type 2 diabetes.

Apolipoprotein E2↗
PubMed2004

Rate of production of plasma and very-low-density lipoprotein (VLDL) apolipoprotein C-III is strongly related to the concentration and level of production of VLDL triglyceride in male subjects with different body weights and levels of insulin sensitivity.

Overweight individuals with reduced insulin sensitivity often have mild to moderate hypertriglyceridemia. To investigate the role of apolipoprotein (apo)C-III metabolism in the etiology of hypertriglyceridemia in these individuals, we investigated 10 male subjects with different body weights (body mass index, 24-34 kg/m(2)) and insulin sensitivity (homeostasis model assessment, 4.7-35.0). Total plasma and very-low-density lipoprotein (VLDL) apoC-III kinetics, as well as VLDL triglyceride (TG) and VLDL apoB kinetics, were measured with iv injected stable isotopes. The apoC-III, TG, and apoB levels in VLDL ranged from 2.9-18.2 mg/dl, 0.49-2.89 mmol/liter, and 6.7-29.3 mg/dl, respectively. Mean production rates (PRs) were: VLDL apoC-III, 20.2 +/- 4.1 micromol/d (range, 8.0-44.8); VLDL TG, 26.9 +/- 4.6 mmol/d (range, 10.2-51.1); and VLDL apoB, 4.4 +/- 0.8 micromol/d (range, 1.5-9.1). VLDL apoC-III PRs were significantly correlated with body mass index, homeostasis model assessment, and plasma TG (r = 0.66, P < 0.05; r = 0.80, P < 0.01; r = 0.95, P < 0.001, respectively). Similar correlations were found for plasma apoC-III PRs (r = 0.70, P < 0.05; r = 0.67, P < 0.05; r = 0.80, P < 0.01, respectively). Fractional catabolic rates (FCRs) were not significantly related to metabolic variables. VLDL TG levels were strongly related to VLDL apoC-III levels (r = 0.99, P < 0.001) and VLDL apoC-III PRs (r = 0.94, P < 0.001). VLDL apoC-III levels were more strongly correlated with VLDL TG PRs (r = 0.81, P < 0.01) than with VLDL TG FCRs or VLDL apoB FCRs (r = -0.53, P = 0.12; r = -0.37, P = 0.29). These results suggest that increased hepatic production of VLDL apoC-III is characteristic of subjects with higher body weights and lower levels of insulin sensitivity and is strongly related to the plasma concentration and level of production of VLDL TG.

Adult↗
PubMed2003

Relationships between low-density lipoprotein particle size, plasma lipoproteins, and progression of coronary artery disease: the Diabetes Atherosclerosis Intervention Study (DAIS).

BACKGROUND: The Diabetes Atherosclerosis Intervention Study showed that treatment with fenofibrate decreases progression of coronary atherosclerosis in subjects with type 2 diabetes. We determined whether on-treatment plasma lipid concentrations and LDL particle size contribute to the favorable effect of fenofibrate on the progression of coronary artery disease (CAD). METHODS AND RESULTS: A total of 418 subjects with type 2 diabetes were randomly assigned to 200 mg micronized fenofibrate daily or placebo. The mean follow-up time was 39.6 months. LDL peak particle diameter (LDL size) was determined by polyacrylamide gradient gel electrophoresis from 405 subjects at baseline and at the end of the study. Progression of CAD was measured with quantitative coronary angiography. LDL size increased significantly more in the fenofibrate group than in the placebo group (0.98+/-1.04 versus 0.32+/-0.92 nm, P<0.001). In the combined group, small LDL size was significantly associated with progression of CAD measured as the increase of percentage diameter stenosis (r=-0.16, P=0.002) and decreases in minimum (r=-0.11, P=0.030) and mean (r=-0.10, P=0.045) lumen diameter. High on-treatment LDL cholesterol, apolipoprotein B, and triglyceride concentrations were also associated with the progression of CAD. In regression analyses, small LDL size added to the effect of LDL cholesterol and apolipoprotein B on the progression of CAD. Similar associations were observed in the fenofibrate group, whereas in the placebo group, lipoprotein variables were not significantly correlated with the progression of CAD. CONCLUSIONS: Changes in LDL size and plasma lipid levels account for part of the antiatherogenic effect of fenofibrate in type 2 diabetes.

Adult↗
PubMed2003

Progression of atherosclerosis is associated with variation in the alpha1-antitrypsin gene.

OBJECTIVE: Alpha1-Antitrypsin (AAT) protects elastic tissue and may play a role in atherogenesis. The association of atherosclerosis progression with common AAT variants was considered in 2 clinical trials. METHODS AND RESULTS: We examined the association of AAT V213A, S and Z deficiency alleles, and the functional 3' UTR 11478G>A with change in minimal luminal diameter, a measure of focal disease, in the Lopid Coronary Angiography Trial gemfibrozil study of post-bypass men. S or Z carriers (n=14) showed strong progression of disease on placebo (11.5%) but responded well to treatment (3% regression). 11478A carriers treated with placebo or gemfibrozil showed significantly more disease progression (n=8, -14.5% and n=16, -4.0%, respectively) than 11478GG men (n=107, -7.0% and n=108, -1.4%, respectively; overall, P=0.003). VV213 men treated with gemfibrozil (n=68) showed -4.8% progression, whereas A213 carriers (n=55) showed +1.4% regression of disease (P=0.001). No V213A effect was seen on placebo (P=0.11). In the Diabetes Atherosclerosis Intervention Study fenofibrate trial of angiographic progression in type 2 diabetes, the association of 11478A with increased disease progression was confirmed in the treatment group, but not the gemfibrozil-treated A213 association with regression, suggesting a pharmacogenetic difference. CONCLUSIONS: Disease progression is associated with variation in AAT, and low AAT levels promote atherogenesis.

3' Untranslated Regions↗
PubMed2003

Risk factors for coronary heart disease in women with systemic lupus erythematosus: the Toronto Risk Factor Study.

OBJECTIVE: Because women with systemic lupus erythematosus (SLE) are 5-8 times more likely to develop coronary heart disease (CHD) than are women in the general population, we assessed the prevalence of classic risk factors for CHD in women with SLE. METHODS: Consecutive female patients with SLE who were without evidence of CHD and were attending a large lupus clinic in Toronto were studied. The control population was recruited from among age-matched subjects attending a family practice unit for an annual physical examination. The prevalence of classic CHD risk factors and the 10-year risk of a CHD-related event were determined using the Framingham risk assessment formula. Lipid subfractions, other metabolic risk factors, lifestyle variables, and demographic characteristics were also compared between the 2 groups. RESULTS: We studied 250 SLE patients and 250 controls whose mean +/- SD age was 44.8 +/- 12 years and 44.3 +/- 15 years, respectively. Hypertension and diabetes were significantly more common among the SLE patients. Although the SLE patients had a higher mean number of CHD risk factors per patient, the 10-year risk of a CHD-related event, using the Framingham multiple risk factor assessment, was the same in SLE patients and controls (3.2%). Compared with controls, SLE patients had higher levels of very low-density lipoprotein cholesterol and total triglycerides, and had higher levels of homocysteine despite having higher folate levels. Premature menopause, sedentary lifestyle, and an at-risk body habitus were also more prevalent in SLE patients. CONCLUSION: Women with SLE have a range of detectable coronary risk factors that are not fully reflected in the Framingham risk factor formula. These factors are likely to contribute to the loss of protection from CHD that has been observed in SLE.

Adult↗
PubMed2002

Familial aggregation of diabetes and hypertension in a case-control study of colorectal neoplasia.

Familial aggregation of diseases potentially associated with metabolic syndrome (diabetes mellitus, hypertension, and cardiovascular diseases) was assessed in a colonoscopy-based case-control study of colorectal neoplasia in Toronto and Ottawa, Canada, in 1993-1996. Each familial disease was analyzed by logistic regression using generalized estimating equations. Case probands had incident adenomatous polyps (n = 172) or incident (n = 25) or prevalent (n = 132) colorectal cancer (CRC), while control probands (n = 282) had a negative colonoscopy and no history of CRC or polyps. Significant effect modification was evident in the data, with the strongest positive associations between familial diabetes and colorectal neoplasia among older probands with symptoms (parents: odds ratio (OR) = 2.4, 95% confidence interval (CI): 1.2, 4.8; siblings: OR = 5.8, 95% CI: 2.6, 13.3). Familial hypertension was also associated with colorectal neoplasia among probands with symptoms (OR = 1.7, 95% CI: 1.1, 2.6). In stratified analyses, familial diabetes, hypertension, and stroke were positively associated with adenomatous polyps in subgroups of probands who were older and/or had symptoms, while only familial diabetes was possibly associated with CRC. Associations in other proband groups may have been obscured by high cumulative incidence of parental CRC. Family studies are needed to understand the contribution of specific environmental and genetic factors in accounting for the disease aggregations.

Adult↗
PubMed2002

Structural and compositional changes in very low density lipoprotein triacylglycerols during basal lipolysis.

Triacylglycerols secreted by liver and carried by very low density lipoprotein (VLDL) are hydrolysed in circulation by lipoprotein and hepatic lipases. These enzymes have been shown to have positional and fatty acid specificity in vitro. If there were specificity in basal lipolysis in vivo, triacylglycerol compositions of circulating and newly secreted VLDL would be different. To study this we compared the composition of normal fasting VLDL triacylglycerol of Wistar rats to that obtained after blocking lipolysis by Triton WR1339, which increased plasma VLDL triacylglycerol concentration about 4.7-fold in 2 h. Analyses of molecular species of sn-1,2- and sn-2,3-diacylglycerol moieties and stereospecific triacylglycerol analysis revealed major differences between the groups in the VLDL triacylglycerol composition. In nontreated rats, the proportion of 16:0 was higher and that of 18:2n-6 lower in the sn-1 position. The proportion of 14:0 was lower in all positions and that of 18:0 was lower in the sn-1 and sn-3 positions in nontreated rats whereas the proportions of 20:4n-6, 20:5n-3, 22:5n-3 and 22:6n-3 were higher in the sn-1 and lower in the sn-2 position. These results suggest that the fatty acid of the sn-1 position is the most decisive factor in determining the sensitivity for hydrolysis of the triacylglycerol. In addition, triacylglycerol species with highly unsaturated fatty acids in the sn-2 position also favoured hydrolysis. The in vivo substrate specificity followed only partly that obtained in in vitro studies indicating that the nature of molecular association of fatty acids in natural triacylglycerol affects its susceptibility to lipolysis. To conclude, our results indicate that preferential basal lipolysis leads to major structural differences between circulating and newly secreted VLDL triacylglycerol. These differences extend beyond those anticipated from analysis of total fatty acids and constitute a previously unrecognized feature of VLDL triacylglycerol metabolism.

Animals↗