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Biomedical subjects

Gregory Y Lip

Publications and source records attributed to Gregory Y Lip.

9 recordsLinked to original sources
PubMed2005

Recruitment of ethnic minority patients to a cardiac rehabilitation trial: the Birmingham Rehabilitation Uptake Maximisation (BRUM) study [ISRCTN72884263].

BACKGROUND: Concerns have been raised about low participation rates of people from minority ethnic groups in clinical trials. However, the evidence is unclear as many studies do not report the ethnicity of participants and there is insufficient information about the reasons for ineligibility by ethnic group. Where there are data, there remains the key question as to whether ethnic minorities more likely to be ineligible (e.g. due to language) or decline to participate. We have addressed these questions in relation to the Birmingham Rehabilitation Uptake Maximisation (BRUM) study, a randomized controlled trial (RCT) comparing a home-based with a hospital-based cardiac rehabilitation programme in a multi-ethnic population in the UK. METHODS: Analysis of the ethnicity, age and sex of presenting and recruited subjects for a trial of cardiac rehabilitation in the West-Midlands, UK. PARTICIPANTS: 1997 patients presenting post-myocardial infarction, percutaneous transluminal coronary angioplasty or coronary artery bypass graft surgery. DATA COLLECTED: Exclusion rates, reasons for exclusion and reasons for declining to participate in the trial by ethnic group. RESULTS: Significantly more patients of South Asian ethnicity were excluded (52% of 'South Asian' v 36% 'White European' and 36% 'Other', p < 0.001). This difference in eligibility was primarily due to exclusion on the basis of language (i.e. the inability to speak English or Punjabi). Of those eligible, similar proportions were recruited from the different ethnic groups (white, South Asian and other). There was a marked difference in eligibility between people of Indian, Pakistani or Bangladeshi origin. CONCLUSION: Once eligible for this trial, people from different ethnic groups were recruited in similar proportions. The reason for ineligibility in the BRUM study was the inability to support the range of minority languages.

Aged↗
PubMed2004

Platelet-derived VEGF, Flt-1, angiopoietin-1 and P-selectin in breast and prostate cancer: further evidence for a role of platelets in tumour angiogenesis.

BACKGROUND: Cancer is a complex multi-factorial disorder that may commonly show abnormal angiogenesis in such patients. Recently, platelets have been postulated to have a major role in both these processes, suggesting that antiplatelet strategies may be useful in cancer treatment. MATERIALS AND METHODS: To further investigate the role of platelets in angiogenesis, we used a novel platelet lysate assay to analyse platelet contents in breast cancer (n = 30) and prostate cancer (n = 30) patients and age- and sex-matched controls (n = 60). Markers of angiogenesis (vascular endothelial growth factor (VEGF), angiopoietin-1 and-2 (Ang-1, -2), and their respective receptors (Flt-1 and Tie-2) plus a marker of platelet activation (P-selectin (P-sel)), were all measured in platelet lysate by enzyme-linked immunsorbent assay. RESULTS: Platelet lysate from breast cancer patients contained higher levels of VEGF (P < 0.0001). Ang-1 (P = 0.0186) and P-sel (P = 0.0002), compared to healthy controls. Platelet lysate from prostate cancer patients had elevated VEGF (P = 0.008) but not Ang-1 or P-sel. There were no significant differences between levels of Fit-1 between patients and controls, and both Ang-2 and Tie-2 were undetectable in both patient groups and control platelet lysate. CONCLUSION: We have shown that our previously developed platelet lysate technique could be used to measure indices of angiogenesis, and their respective receptors, and that this assay can be applied to patients with cancer. Our study also provides further evidence that platelets may influence angiogenic abnormalities in human cancer. The platelet may be a useful target in anti-cancer strategies.

Aged↗
PubMed2003

Congestive heart failure and Virchow's triad: a neglected association.

Congestive heart failure (CHF) is associated with significant morbidity and mortality. In particular, patients with CHF have a high risk of venous thromboembolism and stroke, as well as recurrent ischaemia and infarction. However, in large heart failure trials, such thrombotic complications have often been regarded as less important end points than total mortality or readmission to hospital. In addition, a high proportion of mortality in CHF is due to sudden cardiac death (SCD). Although it was long thought that SCD was due to malignant arrhythmias, current evidence suggests that thrombosis also has a significant part to play. Thrombosis in CHF may therefore be a much more significant problem than is generally appreciated. CHF is associated with abnormalities of flow (low cardiac output, dilated cardiac chambers), vessel wall (endothelial dysfunction), and abnormalities of blood constituents (abnormalities of platelets and haemorrheology). Thus it fulfills all of Virchow's triad of characteristics of a prothrombotic state. In view of these findings, antithrombotic therapy ought to provide a substantial morbidity and mortality benefit to patients with CHF. However, current data is conflicting, and comes from non-randomised, retrospective analyses of major heart failure trials, and a few randomised trials of anticoagulants in CHF that are more than 50 years old. Prospective trials of warfarin and antiplatelet agents in CHF are in progress. Measures to identify patients at highest risk of thrombosis may help to guide treatment. Further study into the relationships between such markers and the severity of heart failure, the value of such markers in predicting thrombotic complications in CHF, and the effect of treatments, is therefore needed.

Anticoagulants↗
PubMed2003

Extracellular matrix biology: a new frontier in linking the pathology and therapy of hypertension?

The extracellular matrix (ECM) is a vital component of connective tissue, and collagen is a major constituent. There is growing evidence that changes in the composition of the cardiac and vascular matrix occurs during hypertension. Clinically, these effects are manifested as left ventricular hypertrophy and a reduction in arterial compliance and luminal diameter, which results in end organ ischaemia. The matrix metalloproteinases and their inhibitors have a central role in the regulation of the composition of the ECM. In this review, we discuss the mediators that affect the structure of the ECM in hypertension using results from animal and human studies.

Animals↗
PubMed2003

Acute coronary syndromes: Virchow's triad revisited.

The acute coronary syndromes (ACS), which include unstable angina, non-ST-segment and ST-segment elevation acute myocardial infarction, all share common pathophysiology processes that are characterized by coronary plaque disruption with superimposed thrombus formation, leading to myocardial ischaemia. A greater understanding of these processes has enable us to correlate the abnormalities in arterial vessel wall substrates ('vessel abnormalities'), rheologic and biomechanical conditions ('abnormal flow'), and blood thrombogenicity ('abnormal blood constituents') to the contribution of coronary plaque disruption and subsequent thrombosis, with the basic concepts of Virchow's triad for thrombus formation (thrombogenesis) described about 150 years ago. This improved understanding has led to the identification of newer therapeutic targets and, hence, novel pharmacological agents targeting different components of Virchow's triad, particularly in altering thrombus formation and plaque vulnerability.

Acute Disease↗