PubMed Health⌕ Search

Biomedical subjects

Michelle Lambert-Hammill

Publications and source records attributed to Michelle Lambert-Hammill.

7 recordsLinked to original sources
PubMed2006

Cardiovascular risk factors determine erectile and arterial function response to sildenafil.

BACKGROUND: Erectile dysfunction is related to endothelial function. Cardiovascular risk factors determine endothelial function. Sildenafil is effective in treatment of erectile dysfunction but shows variable results. This study investigated the relationship of cardiovascular risk factors to acute and chronic responses to sildenafil. METHODS: Cardiovascular risk factors and acute and chronic pulse wave responses to a single 50-mg dose of sildenafil were assessed in 45 patients with erectile dysfunction confirmed by low international index of erectile function (IIEF) score before and after chronic therapy with sildenafil. RESULTS: On recruitment all patients showed evidence of erectile dysfunction with an IIEF score of 5 points (1 to 20 points). Chronic sildenafil therapy resulted in an increase of IIEF score of 13 points (range -1 to +24 points) and 24 patients (53%) achieved an IIEF score>or=21 points. Improvement in erectile function in response to sildenafil (rn=0.79; P<.001) was dependent on initial erectile function (P=.002) and baseline apolipoprotein B (P=.01). Vascular responses to acute treatment with sildenafil were assessed using pulse wave analysis. Acute changes in stiffness index induced by sildenafil (rn=0.65; P<.001) were related to apolipoprotein A-1 (P=.006), B (P=.02), and lipoprotein(a) (P=.008) concentrations, whereas reflection index (rn=0.69; P<.001) was related to pulse pressure (P<.001), albumin-to-creatinine ratio (P=.007), and lipoprotein(a) (P=.02). CONCLUSIONS: The extent of acute and chronic effects of sildenafil on erectile function and pulse wave profiles is determined by metabolic cardiovascular risk factors. Improved cardiovascular risk factor control is likely to increase the efficacy of phosphodiesterase-5 inhibitor therapy in the treatment of erectile dysfunction.

Aged↗
PubMed2005

Asymmetric dimethyl arginine levels correlate with cardiovascular risk factors in patients with erectile dysfunction.

BACKGROUND: Erectile dysfunction is related to penile arterial endothelial nitric oxide production. Asymmetric dimethylarginine (ADMA) and E-selectin are often considered plasma markers of endothelial function. OBJECTIVE: This study investigated the relationship between these plasma markers and cardiovascular risk factors in patients with erectile dysfunction. METHODS AND RESULTS: Cardiovascular risk factors, ADMA and E-selectin were assessed in 45 patients with erectile dysfunction. Plasma markers showed associations with baseline risk factors. E-selectin levels showed an inverse relationship with age (p = 0.005) and statin therapy (p = 0.03) and a weak association with concomitant beta-blocker therapy (p = 0.05). Compared to these relatively weak associations with cardiovascular risk factors, ADMA levels showed strong associations with pulse pressure (p < 0.001), lack of smoking (p = 0.002) and lipoprotein (a) (p = 0.004) concentrations and weak associations with LDL-cholesterol (p = 0.02), and C-reactive protein levels (p = 0.04). ADMA levels correlated with E-selectin (partial r = 0.76; p < 0.001) after adjustment for lipoprotein (a), pulse pressure and smoking. No change in E-selectin or ADMA levels was seen after 70 days therapy with sildenafil and no relationship was found between either plasma marker and the acute pulse wave response to a single challenge dose of sildenafil. CONCLUSION: ADMA levels correlate at baseline with some cardiovascular risk factors including inflammatory markers and lipoprotein (a) in patients with erectile dysfunction.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed2005

Impaired renal function and atherosclerosis in a Pakistani cohort.

OBJECTIVE: To investigate the relationship of creatinine and calculated glomerular filtration rate (GFR) with coronary arterial disease (CAD) in Pakistani patients. SUBJECTS: Four hundred individuals with chest pain; 200 with angiographic disease matched with 200 without occlusive disease. DESIGN: A prospective case-control study. SETTING: A tertiary referral cardiology unit in Pakistan. RESULTS: Impaired renal function as estimated by calculated GFR was common in this population. Creatinine and glomerular filtration rate, as calculated by the Cockcroft-Gault (CG) and Modification of Diet in Renal Disease (MDRD) formulae, were associated with CAD and atherosclerotic burden in Pakistani patients. Calculation of creatinine clearance, correcting for age, sex and body mass index, showed that clearance was 81 (17-257) mL/min/1.73 m2 in patients with CAD compared with 88 (23-167) mL/min/1.73 m2 in controls with a significant number of patients (18.5 vs. 6.5%; RR = 2.85; p < 0.001) showing significant renal impairment (< 60 mL/min/1.73 m2) by CG and more by the MDRD equation (26 vs. 9%; RR = 2.88; p < 0.001). The unadjusted odds ratios for CAD for a GFR < 60 mL/min/1.73 m2 were 3.66 (1.87-7.16) and 3.29 (1.81-6.01), respectively and, after adjustment for diabetes, smoking, insulin resistance, inflammation and apolipoprotein A1, 1.04 (1.02-1.09) and 1.04 (1.02-1.09), respectively. CONCLUSIONS: Impaired renal function is common in Pakistani patients with coronary arterial disease and is strongly associated with a risk of atherosclerosis independent of insulin resistance.

Adult↗
PubMed2004

Waist-hip ratio and low HDL predict the risk of coronary artery disease in Pakistanis.

OBJECTIVE: To establish risk factor causal associations for coronary artery disease (CAD) in the native Pakistani population. METHODS: We conducted a hospital-based, case-control study of 200 cases with angiographically documented CAD and 200 age- and sex-matched controls without angiographic evidence of CAD. Patients on lipid lowering therapy were excluded. Lifestyle, anthropometric and biochemical risk factors were assessed in both groups. RESULTS: The presence of CAD was associated with current, past or passive smoking, a history of diabetes and high blood pressure, a positive family risk factors in this study; levels were below history of CAD, body fat percentage, waist-hip ratio (WHR), low apolipoprotein A1 or low HDL, lipoprotein (a), glucose, insulin, insulin resistance, C-reactive protein (CRP), total cholesterol to HDL ratio (TC/HDL) and creatinine on univariate conditional logistic regression analysis. In multiple regression analysis, significant independent associations were found with low HDL (OR 0.11; 95% CI 0.04-0.34; p < 0.001) positive family history (OR 1.79; 95% CI 1.09-2.93; p = 0.02), CRP (OR 1.45; 95% CI 1.19-1.75; p < 0.001) and WHR (OR 1.04; 95% CI 1.01-1.08; p = 0.01). Angiograms were also quantified for the extent and severity of CAD by the Gensini scoring system. Quantitative angiographic data showed associations with age (p = 0.01), the duration of diabetes (p = 0.04), WHR (p = 0.06), low HDL (p < 0.001), lipoprotein (a) (p = 0.001), creatinine (p < 0.001) and CRP (p = 0.007). Results indicate that total and LDL cholesterol were not significant currently accepted thresholds for treatment. CONCLUSIONS: The cardiovascular risk profile in this population is consistent with metabolic syndrome where low HDL and WHR can be used to predict the risk of CAD. Results suggest the need to redefine the currently practised approach to CAD management in this population to fit local needs.

Adult↗
PubMed2004

Determinants of left ventricular mass in aortic stenosis.

BACKGROUND AND AIM OF THE STUDY: There are many possible determinants of left ventricular (LV) mass, including the angiotensin-converting enzyme (ACE) genotype, which have rarely been compared in aortic stenosis (AS). The study aim was to investigate these determinants in patients with all grades of AS. METHODS: Transthoracic echocardiography and an analysis of ACE genotype was performed in 91 patients with aortic valve thickening and a peak aortic velocity >2.0 m/s. RESULTS: Univariate relationships were identified between LV mass index and effective orifice area (R = 0.22), and peak transaortic pressure difference (R = 0.36). LV mass index was similar for the ACE-II (152+/-37 g/m2), ACE-ID (145+/-46 g/m2) and ACE-DD (161+/-56 g/m2) genotypes. LV mass index was significantly greater in males (162+/-52 gm/m2) than in females (137+/-38 gm/m2; p = 0.014). The multivariate determinants varied according to the grade of AS: diastolic blood pressure (p = 0.028) in mild stenosis; peak transaortic pressure difference (p = 0.03) in moderate stenosis; and peak transaortic pressure difference (p <0.0001) and gender (p = 0.02) in severe stenosis. LV hypertrophy was present in 15 of 24 patients (63%) with mild AS, in 21 of 27 (78%) with moderate AS, and 32 of 40 (80%) with severe AS. CONCLUSION: LV hypertrophy is common, even in mild AS, when it is independently related only to the systemic blood pressure. This suggests that antihypertensive agents should be considered early in the natural history of AS.

Aged↗
PubMed2002

The apolipoprotein E2 allele modulates activity and maximal velocity of the sodium-lithium countertransporter.

BACKGROUND: Alterations in erythrocyte sodium-lithium countertransport (SLC) activity and its maximal velocity (Vmax) are associated with hypertension and hypertriglyceridemia. The presence of apolipoprotein (apo) E variants is associated with hypertriglyceridemia. This study investigated the relationship between apoE phenotype and SLC kinetics. METHODS: Cardiovascular risk factors and SLC kinetics were measured in 171 subjects and 69 controls. Apolipoprotein E phenotypes were determined by Western blotting. RESULTS: Patients were 51% male, aged 56+/-13 years, with a blood pressure (BP) of 134+/-22/81+/-11 mm Hg, total cholesterol of 6.71+/-1.57 (256+/-61 mg/dL); median triglycerides 1.65 mmol/L (146 mg/dL) (range, 0.31 to 9.85 mmol/L; 27 to 872 mg/dL) and high-density lipoprotein (HDL) 1.39+/-0.43 mmol/L (54+/-16.6 mg/dL); fasting glucose 4.91+/-0.61 mmol/L (88.5+/-11.0 mg/dL); median insulin 11.7 IU/L (range, 3.7 to 39.8 IU/L). Phenotype frequencies were E3/E3 56%, E2/E3 14%, E2/E2 1%, E3/E4 27%, and E4/E4 2%. The SLC activity, Vmax, and sodium affinity (Km) were not significantly different with respect to apoE phenotype in simple analysis by Kruskal Wallis test. However, in multiple regression analysis after exclusion of BP, a strong co-correlate of SLC activity, the presence of an apoE2 allele was associated reduced activity (beta = -0.061; P = .01) along with HDL:apoA1 ratio (beta = -0.170; P < .001), whereas for the kinetic parameter Vmax, associations were found with triglyceride (beta = 0.029; P = .04), HDL:apoA1 ratio (beta = -0.186; P = .03) and the presence of an apoE2 allele (beta = -0.089; P = .04). CONCLUSIONS: These findings suggest that the apoE phenotype may modulate SLC activity and that the presence of an apoE2 allele phenotype is associated with lower SLC activity and Vmax.

Adult↗