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Biomedical subjects

A Gaw

Publications and source records attributed to A Gaw.

At least 19 recordsLinked to original sources
PubMed2002

Are we negating the benefits of CABG by forgetting secondary prevention?

UNLABELLED: The objective of the study was to examine medically managed secondary prevention at one year after coronary artery bypass grafting (CABG). In all, 214 consecutive patients undergoing isolated elective CABG seen four weeks preoperatively and one year post-operatively. Preoperative systolic blood pressure averaged 135+/-20 mmHg, which increased to 148+/-25 mmHg (P<0.0001) as did diastolic pressure (81+/-12 to 87+/-13 mmHg; P<0.0001). Anginal symptoms were reported by 45.1% (P<0.0001) although median severity scored lower (4.0 [3.0-5.4] vs 0 [0-2.0]; P<0.0001). Breathlessness decreased from 93% to 64% (P<0.0001) and was scored less severely (4.0 [2.0-5.0] vs 2.0 [0-4.0]; P<0.0001. In all, 88% with postoperative angina reported dyspnoea against 44% of those without (P<0.0001). Calcium antagonist use was more common in patients with angina (27.2% vs 5.1%; P<0.0001), but not nitrates (P=0.8695), diuretics (P=0.4218), digoxin (P=0.2565), beta-blockers (P=0.0820), or ACE inhibitors (P=0.7256). Preoperatively 166 patients (80.2%) took aspirin vs 69.2% afterwards (P=0.0131). Twelve patients (6.5%) received warfarin after operation vs none preoperatively. Two took digoxin (0.97%) preoperatively and 14 (7.7%) postoperatively (P=0.001) for chronic atrial fibrillation. One of these took warfarin. Long-acting nitrate use fell from 63.4% to 15.8% (P <0.0001). Short-acting nitrate use fell similarly (P<0.0001). Preoperatively 37 patients (17.9%) took ACE inhibitors vs 44 postoperatively (24.2%); 39 had not received them before. Preoperatively 48 (23.2%) took diuretics vs 30 (16.5%) postoperatively (P=0.127); 24 had not previously taken diuretics. More patients took HMGCoA inhibitors postoperatively (P=0.0068) and total cholesterol was significantly reduced with a concomitant increase in HDL fraction. Smoking habit was virtually unchanged from 17.8% to 15.1% (P=0.5023). IN CONCLUSION: angina was common. Apart from statin prescribing, postoperative secondary prevention measures were poorly applied, less widespread and less effective than preoperatively. The implications are disturbing.

Angina Pectoris↗
PubMed2002

Testing cognitive function in elderly populations: the PROSPER study. PROspective Study of Pravastatin in the Elderly at Risk.

OBJECTIVES: For large scale follow up studies with non-demented patients in which cognition is an endpoint, there is a need for short, inexpensive, sensitive, and reliable neuropsychological tests that are suitable for repeated measurements. The commonly used Mini-Mental-State-Examination fulfils only the first two requirements. METHODS: In the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER), 5804 elderly subjects aged 70 to 82 years were examined using a learning test (memory), a coding test (general speed), and a short version of the Stroop test (attention). Data presented here were collected at dual baseline, before randomisation for active treatment. RESULTS: The tests proved to be reliable (with test/retest reliabilities ranging from acceptable (r=0.63) to high (r=0.88) and sensitive to detect small differences in subjects from different age categories. All tests showed significant practice effects: performance increased from the first measurement to the first follow up after two weeks. CONCLUSION: Normative data are provided that can be used for one time neuropsychological testing as well as for assessing individual and group change. Methods for analysing cognitive change are proposed.

Aged↗
PubMed2002

The anatomy of a clinical trial. The West of Scotland Coronary Prevention Study.

OBJECTIVE: Treatment of hyperlipidemia to reduce the risk of ischemic heart disease was, prior to the statin era, disappointingly limited in its ability to yield the benefits expected from the strong relationship known to exist between serum cholesterol and coronary death. Three primary prevention trials, using clofibrate, cholestyramine and gemfibrozil, had achieved modest reductions in fatal and nonfatal coronary events but none was able to extend life overall or even to reduce cardiovascular mortality; and combined analyses of the three raised disquiet over potential links between cholesterol reduction, cancer and aggressive or violent behaviour. The time was therefore ripe to determine whether statins could help prevent that first and all important myocardial infarction. METHODS: The West of Scotland Coronary Prevention Study recruited 6,595 45- to 64-year-old men with no history of prior myocardial infarction and with low-density lipoprotein cholesterol in the range 4-6 mmol/l (155-232 mg/dl). Subjects who had undergone coronary revascularisation or had been hospitalised for angina pectoris in the previous 12 months were excluded, as were those with significant electrocardiographic abnormalities. Participants were randomised to receive pravastatin 40 mg/day or matching placebo and were followed for an average of 4.9 years. RESULTS: Treatment with pravastatin reduced the combined risk of fatal and nonfatal myocardial infarction by 31%. Cardiovascular death overall fell by 32% and the need for coronary revascularisation procedures was reduced by 37%. All of these endpoint benefits were statistically significant. Because there was no increase in non-cardiovascular mortality, the reduction in death from any cause also proved to be statistically significant (p = 0.051 by log rank test and p = 0.037 after adjustment for baseline risk factors). CONCLUSIONS: The West of Scotland Coronary Prevention Study is the first to show that cholesterol reduction with pravastatin helps avoid the first myocardial infarction, reduces coronary mortality and extends life. Ongoing exploration of the study database continues to unearth additional surprisingly beneficial effects of the treatment and permits authoritative decision-making on the effective use of lipid-lowering drugs.

Aged↗
PubMed2002

Primary prevention: a simple, effective means of risk reduction.

Individuals without overt coronary heart disease (CHD) may nevertheless be at significant risk for future CHD events based on lipid and other risk factors. Recognition of this fact is reflected in the inclusion of measures of global risk in current CHD prevention guidelines. Given the fact that many patients in the primary prevention setting fail to achieve target lipid levels, simplicity of treatment can be considered to be of great importance. Drug treatment that can improve achievement of low-density lipoprotein cholesterol (LDL-C) targets and produce beneficial effects on other lipid risk factors at starting doses would be of considerable utility in this setting. A new statin, rosuvastatin, has been shown to produce greater reductions in LDL-C and to permit more patients to reach target levels than currently available statins, and has also demonstrated favorable effects on other lipid variables. Rosuvastatin may thus be a prime candidate for use in clinical practice to achieve the lipid goals recommended in guidelines for primary prevention of CHD.

Anticholesteremic Agents↗
PubMed2001

Plasma leptin and the risk of cardiovascular disease in the west of Scotland coronary prevention study (WOSCOPS).

BACKGROUND: Leptin plays a role in fat metabolism and correlates with insulin resistance and other markers of the metabolic syndrome, independent of total adiposity. Therefore, we hypothesized that raised leptin levels may identify men at increased risk of a coronary event in the West of Scotland Coronary Prevention Study (WOSCOPS). Methods and Results- Plasma leptin levels were measured at baseline in 377 men (cases) who subsequently experienced a coronary event and in 783 men (controls) who remained free of an event during the 5-year follow-up period of the study. Controls were matched to cases on the basis of age and smoking history and were representative of the entire WOSCOPS cohort. Leptin levels were significantly higher in cases than controls (5.87+/-2.04 ng/mL versus 5.04+/-2.09 ng/mL, P<0.001). In univariate analysis, for each 1 SD increase in leptin, the relative risk (RR) of an event increased by 1.25 (95% confidence interval [CI], 1.10 to 1.43; P<0.001). There was minimal change in this RR with correction for body mass index (RR, 1.24; 95% CI, 1.06 to 1.45; P=0.006) or with further correction for classic risk factors, including age, lipids, and systolic blood pressure (RR, 1.20; 95% CI, 1.02 to 1.42; P=0.03). Leptin correlated with C-reactive protein (r=0.24, P<0.001) and, even with this variable added to the model, leptin retained significance as a predictor of coronary events (RR, 1.18; 95% CI, 1.00 to 1.39; P=0.05) at the expense of C-reactive protein. CONCLUSIONS: We show, for the first time, in a large prospective study that leptin is a novel, independent risk factor for coronary heart disease.

Age Factors↗
PubMed2001

Pravastatin and the development of diabetes mellitus: evidence for a protective treatment effect in the West of Scotland Coronary Prevention Study.

BACKGROUND: We examined the development of new diabetes mellitus in men aged 45 to 64 years during the West of Scotland Coronary Prevention Study. METHODS AND RESULTS: Our definition of diabetes mellitus was based on the American Diabetic Association threshold of a blood glucose level of >/=7.0 mmol/L. Subjects who self-reported diabetes at baseline or had a baseline glucose level of >/=7.0 mmol/L were excluded from the analyses. A total of 5974 of the 6595 randomized subjects were included in the analysis, and 139 subjects became diabetic during the study. The baseline predictors of the transition from normal glucose control to diabetes were studied. In the univariate model, body mass index, log triglyceride, log white blood cell count, systolic blood pressure, total and HDL cholesterol, glucose, and randomized treatment assignment to pravastatin were significant predictors. In a multivariate model, body mass index, log triglyceride, glucose, and pravastatin therapy were retained as predictors of diabetes in this cohort. CONCLUSIONS: We concluded that the assignment to pravastatin therapy resulted in a 30% reduction (P:=0.042) in the hazard of becoming diabetic. By lowering plasma triglyceride levels, pravastatin therapy may favorably influence the development of diabetes, but other explanations, such as the anti-inflammatory properties of this drug in combination with its endothelial effects, cannot be excluded with these analyses.

Anticholesteremic Agents↗
PubMed2001

Healthy ageing: addressing acute coronary syndrome?

Acute coronary syndromes contribute significantly to the patterns of morbidity and mortality in the elderly. A meta-analysis of the pathology of acute myocardial infarction has shown that 80-90% of episodes result from the rupture of small, unstable lesions that cause <70% diameter stenosis. Statins have been shown to stabilize the architecture of atherosclerotic plaques in humans and in animals. Statin treatment has also been shown to restore endothelial function, inhibit platelet thrombus formation and exert an anti-inflammatory effect. Collectively, these data support the use of statin therapy in those at risk for acute coronary syndromes, of whom the elderly are foremost.

Acute Disease↗
PubMed2001

Simvastatin: building on success.

Over a decade after launch, simvastatin remains the most widely-prescribed statin in the UK. This has resulted from a growing body of long-term outcome data, a steadily expanded range of indications, an extended dose range and proven cost-efficacy.

Aged↗
PubMed2001

Statins--similarities and differences.

The number of statins available to physicians continues to grow, leading to the question: Are all statins alike? Comparisons of side effects and safety profiles and the dose-response relationship among the different drugs show similar results. The cholesterol-lowering action of each depends on its ability to lower low-density lipoprotein cholesterol (LDL-C). On the other hand, the molecular structures of the newer statins are not similar and could have an effect on the mechanism of action of the compounds. Differences in metabolism also suggest the possibility of serious drug-drug interactions, and differences in levels of lipid reduction at varying dosages among the statins point to clinical variation as well.

Anticholesteremic Agents↗
PubMed2000

Parathyroid hormone potentiates nucleotide-induced [Ca2+]i release in rat osteoblasts independently of Gq activation or cyclic monophosphate accumulation. A mechanism for localizing systemic responses in bone.

The regulation of tissue turnover requires the coordinated activity of both local and systemic factors. Nucleotides exist transiently in the extracellular environment, where they serve as ligands to P2 receptors. Here we report that the localized release of these nucleotides can sensitize osteoblasts to the activity of systemic factors. We have investigated the ability of parathyroid hormone (PTH), a principal regulator of bone resorption and formation, to potentiate signals arising from nucleotide stimulation of UMR-106 clonal rat osteoblasts. PTH receptor activation alone did not lead to [Ca(2+)](i) elevation in these cells, indicating no G(q) coupling, however, activation of G(q)-coupled P2Y(1) receptors resulted in characteristic [Ca(2+)](i) release. PTH potentiated this nucleotide-induced Ca(2+) release, independently of Ca(2+) influx. PTH-(1-31), which activates only G(s), mimicked the actions of PTH-(1-34), whereas PTH-(3-34), which only activates G(q), was unable to potentiate nucleotide-induced [Ca(2+)](i) release. Despite this coupling of the PTHR to G(s), cAMP accumulation or protein kinase A activation did not contribute to the potentiation. 3-Isobutyl-1-methylxanthine, but not forskolin effectively potentiated nucleotide-induced [Ca(2+)](i) release, however, further experiments proved that cyclic monophosphates were not involved in the potentiation mechanism. Costimulation of UMR-106 cells with P2Y(1) agonists and PTH led to increased levels of cAMP response element-binding protein phosphorylation and a synergistic effect was observed on endogenous c-fos gene expression following costimulation. In fact the calcium responsive Ca/cAMP response element of the c-fos promoter alone was effective at driving this synergistic gene expression. These findings demonstrate that nucleotides can provide a targeted response to systemic factors, such as PTH, and have important implications for PTH-induced signaling in bone.

1-Methyl-3-isobutylxanthine↗
PubMed2000

Is lipoprotein(a)-cholesterol a better predictor of vascular disease events than total lipoprotein(a) mass? A nested case control study from the West of Scotland Coronary Prevention Study.

The clinical utility of a new assay for plasma lipoprotein(a)-cholesterol (Lp(a)-C) was assessed in parallel with our routine Lp(a) mass measurements in a nested-case control study of subjects within the placebo arm of the West of Scotland Coronary Prevention Study (WOSCOPS). A total of 238 control patients and 108 patients who had suffered a serious vascular event during the course of the WOSCOPS were examined. Lp(a) mass was assessed within 2 years of sampling by an ELISA method on baseline EDTA plasma samples which had been stored at -70 degrees C. Subsequently, the Lp(a) mass was re-measured by an immunoturbidimetric assay approximately 8 years after sampling. On the same stored aliquot the Lp(a)-C was measured. These analyses allowed us to assess whether the Lp(a)-C assay could provide any additional information over and above that which would be obtained from our Lp(a) mass assays. In addition the apo(a) isoform sizes of these subjects were measured using a high resolution immunoblotting system. The Lp(a)-C and Lp(a) mass measurements provided exactly the same information in the study, as they were equally non-discriminatory between cases and controls. The only difference between the two patient groups was the percentage of 'null' apo(a) alleles (control: 25.6% versus cases: 19.4%). We conclude that these results reinforce the concordance of the two assay systems and confirm that the Lp(a)-C assay provides no added information over and above that gained from traditional Lp(a) mass assays, which may be faster and less expensive.

Case-Control Studies↗
PubMed2000

At what level of coronary heart disease risk should a statin be prescribed?

Statin therapy has been conclusively shown to offer patients clinical benefit, virtually irrespective of their baseline risk status. However, the absolute risk reductions observed in different clinical trials, which have recruited patients across a spectrum of lipid levels and vascular disease states, show that baseline global risk determines the absolute benefit gained and in turn will specify the number of patients needed to be treated in order to realize this benefit. Global risk assessment is therefore central to the clinically meaningful use of statin therapy, and a strong case is now argued in the literature for a high-risk primary prevention strategy that goes hand in hand with standard secondary prevention. The routine use of Framingham-based risk assessment tools is advocated because these are the most widely evaluated and have been repeatedly shown to predict the risk of coronary heart disease accurately in western populations. The risk threshold in primary prevention that should determine pharmacological intervention is the subject of controversy. The currently used annual risk figure of 3% would clearly capture all very high-risk individuals but would also deny treatment to many individuals who will subsequently die from their first coronary event. Although a 1.5% annual risk threshold is economically untenable in the present UK health system, a level of 2% is, we believe, both achievable and affordable.

Age Factors↗
PubMed2000

Analytical performance of the Genzyme LipoPro Lp(a) kit for plasma lipoprotein(a)-cholesterol assay.

The analytical performance of a new assay for plasma lipoprotein(a)-cholesterol (Lp[a]-C) was compared with that of our existing Lp(a) protein assay. The Lp(a)-C assay utilises lectin affinity chromatography to isolate intact Lp(a) particles. The effect of apo(a) isoform size on this system was assessed and found to be negligible. Plasma Lp(a) concentrations measured by both assays were in excellent accord in 24 subjects with Lp(a) protein concentrations ranging from 1-65 mg/dL (r2 = 0.916). Linearity of the Lp(a)-C assay system was excellent (r2 = 0.997) and within-run precision was 6.9% at an Lp(a)-C concentration of 0.3 mmol/L. Between-calibration precision was checked and proved to be 7.9%. The lectin-binding reagent used in the assay bound different sized apo(a) isoforms equally, and the recovery of Lp(a) from the reagent was, on average, 64%. We conclude that the Lp(a)-C assay system performs well but that further information is required on what new information, if any, the assay provides over traditional Lp(a) protein measurements by enzyme-linked immunosorbent assay (ELISA) or immunoturbidimetry.

Biomarkers↗
PubMed1999

The design of a prospective study of Pravastatin in the Elderly at Risk (PROSPER). PROSPER Study Group. PROspective Study of Pravastatin in the Elderly at Risk.

The PROspective Study of Pravastatin in the Elderly at Risk (PROSPER) is a randomized, double-blind, placebo-controlled trial designed to test the hypothesis that treatment with pravastatin will diminish risk of subsequent major vascular events in a cohort of men and women (70 to 82 years old) with preexisting vascular disease or significant risk of developing this condition. Five thousand eight hundred four men and women in addition to receiving advice on diet and smoking, have been randomized equally to treatment with 40 mg pravastatin/day or matching placebo in 3 centers (Cork, Ireland, Glasgow, Scotland, and Leiden, The Netherlands). Following an average 3.5-year intervention period, a primary assessment will be made of the influence of this therapy on major vascular events (a combination of coronary heart disease, death, nonfatal myocardial infarction, and fatal and nonfatal stroke). A number of additional analyses will also be conducted on the individual components of the primary end point, on men, on women, and on subjects with and without previous evidence of vascular disease. Finally, an assessment will be made of the effects of treatment on cognitive function, disability, hospitalization or institutionalization, vascular mortality, and all-cause mortality.

Aged↗
PubMed1999

Predictors of plasma lipoprotein(a) concentration in the West of Scotland Coronary Prevention Study cohort.

An elevated plasma lipoprotein(a) (Lp(a)) concentration is an independent risk factor for coronary heart disease (CHD). Plasma Lp(a) levels are believed to be predominantly controlled by the APO(a) gene, which encodes the apo(a) glycoprotein moiety of the Lp(a) particle. However, other parameters in the lipoprotein profile as well as co-existing disease states or personal traits have been proposed as co-varieties. In order to examine these potential controlling factors in greater detail than previously possible, 1760 unrelated Caucasian subjects were studied, from which were identified 907 with a single expressing APO(a) allele. This strategy was followed to obviate the difficulty in dealing with the co-expression of different apo(a) isoforms and the resulting compound plasma Lp(a) level. After cube-root transformation of the plasma Lp(a) levels to normalise their distribution, a series of correlates were computed. There was no good correlation between Lp(a) concentration and any other measured lipid or lipoprotein in the lipid profile or with any other variable examined, with the important exception of the length of the expressed apo(a) isoform (r = -0.491, P = 0.0001). We conclude that in this population the plasma Lp(a) concentration is not predicted by the plasma lipid profile, alcohol intake, or smoking status but is predicted, albeit incompletely, by the length polymorphism of the APO(a) gene.

Age Distribution↗