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Biomedical subjects

B M Cheung

Publications and source records attributed to B M Cheung.

At least 19 recordsLinked to original sources
PubMed2001

Increase in plasma adrenomedullin in patients with heart failure characterised by diastolic dysfunction.

OBJECTIVE: To investigate the relation between plasma adrenomedullin and the severity of diastolic dysfunction in patients with heart failure. DESIGN: Prospective study. SETTING: University teaching hospital. PATIENTS: 77 patients (mean (SEM) age 66.3 (1.2) years; 75% male) who were being followed in the outpatient clinic after admission to hospital for acute heart failure. INTERVENTIONS: Same day echocardiography with Doppler studies; determination of venous adrenomedullin concentration by radioimmunoassay. MAIN OUTCOME MEASURES: Plasma adrenomedullin concentration and its correlation with systolic and diastolic function. RESULTS: 31 patients (40%) had isolated diastolic dysfunction (ejection fraction > 50%), and the remaining 46 had a depressed ejection fraction (< 50%). Of the patients with diastolic dysfunction, 17 had a restrictive filling pattern. In all but one of these there was coexisting systolic failure (chi(2) = 10.7, p = 0.001). Patients with systolic heart failure and a restrictive filling pattern (group 1, n = 16) had a higher plasma adrenomedullin than those with systolic failure and a non-restrictive filling pattern (group 2, n = 30) or with isolated diastolic heart failure and a non-restrictive filling pattern (group 3, n = 30) (mean (SEM): 91.7 (21.1) v 38.4 (8.8) v 34.0 (6.5) pmol/l, both p < 0.05). All heart failure values were higher (p < 0.01) than the control value (6.9 (1.2) pmol/l). Ejection fraction and left ventricular dimensions were similar in groups 1 and 2. Plasma adrenomedullin did not correlate with ejection fraction or New York Heart Association functional class. Stepwise multiple regression analysis showed that the presence of a restrictive filling pattern was the only independent variable associated with a high plasma adrenomedullin. CONCLUSIONS: Plasma adrenomedullin concentrations in patients with heart failure are determined by the presence of diastolic dysfunction, and are especially raised in the presence of a restrictive filling pattern. There appears to be no correlation with systolic dysfunction.

Acute Disease↗
PubMed2001

Cost-effectiveness analysis of applying the Cholesterol and Recurrent Events (CARE) study protocol in Hong Kong.

OBJECTIVE: To determine the cost-effectiveness of secondary prevention with pravastatin in Hong Kong patients with coronary heart disease and average cholesterol levels. DESIGN: Cost-effectiveness analysis based on published results of the CARE study. PATIENTS: Men and women post-myocardial infarction with average cholesterol levels. MAIN OUTCOME MEASURES: Cost-effectiveness analysis: cost per life saved, cost per fatal or non-fatal coronary event prevented, cost per procedure prevented, and cost per fatal or non-fatal stroke prevented. Cost-utility analysis: gross cost and net cost per quality-adjusted life year gained calculated using two alternative models. RESULTS: Cost per life saved or death prevented was HK$4,442,350 (non-discounted); cost per fatal or non-fatal cardiac event prevented HK$1,146,413; cost per procedure prevented HK$732,759; and cost per fatal or non-fatal stroke prevented HK$2,961,566. Net cost per quality adjusted life year gained was HK$73,218 and HK$65,280 non-discounted, respectively using the two alternative models. CONCLUSIONS: The results of this study can assist in prioritising the use of health care resources in Hong Kong but should be considered alongside the benefits and costs of alternative interventions for coronary heart disease.

Adult↗
PubMed2000

Genetic and clinical features of hemoglobin H disease in Chinese patients.

BACKGROUND: Normally, one pair of each of the two alpha-globin genes, alpha1 and alpha2, resides on each copy of chromosome 16. In hemoglobin H disease, three of these four alpha-globin genes are affected by a deletion, a mutation, or both. We studied the alpha1-globin gene abnormalities and the clinical and hematologic features of Chinese patients with hemoglobin H disease in Hong Kong. METHODS: We assessed the clinical features, hematologic values, serum ferritin levels, and liver function of 114 patients with hemoglobin H disease. We also performed echocardiography and magnetic resonance imaging of the liver and examined the two pairs of alpha-globin genes. RESULTS: Hemoglobin H disease in 87 of the 114 patients (76 percent) was due to the deletion of three of the four alpha-globin genes (--/-alpha), a combination termed the deletional type of hemoglobin H. The remaining 27 patients (24 percent) had the nondeletional type of hemoglobin H disease, in which two alpha-globin genes are deleted and a third is mutated (--/alphaalphaT). All 87 patients with the deletional type of hemoglobin H were double heterozygotes in whom there was a deletion of both alpha-globin genes from one chromosome, plus a deletion of the alpha1 or alpha2 gene from the other chromosome (--/alpha- or --/-alpha). A variety of mutated alpha-globin genes was found in the patients with nondeletional type of hemoglobin H disease. Patients with the nondeletional type of the H disease had more symptoms at a younger age, more severe hemolytic anemia, and larger spleens and were more likely to require transfusions than patients with deletional hemoglobin H disease. The severity of iron overload was not related to the genotype. CONCLUSIONS: Chinese patients in Hong Kong with the nondeletional type of hemoglobin H disease have more severe disease than those with the deletional type of the disease. Iron overload is a major cause of disability in both forms of the disease.

Adolescent↗
PubMed2000

Clinical predictors of morbidity and mortality in patients with myocardial infarction or revascularization who underwent cardiac rehabilitation, and importance of diabetes mellitus and exercise capacity.

This investigation was a prospective, follow-up study to assess whether baseline clinical and investigational parameters were predictors of cardiovascular morbidity and mortality in patients enrolled into the cardiac rehabilitation program. A cohort of 418 patients (70% were men) with coronary heart disease was followed up 3.2 +/- 1.1 years. Two hundred twenty-seven of them (54%) had a recent myocardial infarction (MI), with a thrombolytic rate of 54%. Percutaneous transluminal coronary angioplasty (PTCA) was performed in 45% of patients. The covariates assessed include age, gender, smoking habit, body mass index, the presence of hypertension or diabetes mellitus, exercise habit, site and severity of MI, status of thrombolytic therapy, peak creatine phosphokinase, plasma lipid profiles, ejection fraction, PTCA performed, number of diseased coronary arteries, and exercise capacity. Low-density lipoprotein cholesterol decreased significantly (3.2 +/- 1.0 vs 2.7 +/- 0.7 mmol/L, p < 0.001). The cumulative mortality was 13%. In a univariate model, the parameters that significantly predict mortality included older age, diabetes, low exercise capacity (< or = 4 metabolic equivalents) 3-vessel disease, those without PTCA performed, and a low ejection fraction. In the Cox proportional-hazards model analysis, the independent factors were coexisting diabetes (chi-square 6.1, p = 0.01) and a low metabolic equivalent (chi-square 6.5, p = 0.01). One hundred six patients were rehospitalized for nonfatal cardiovascular events that included unstable angina (48%), heart failure (21%), acute MI (6%), symptomatic arrhythmia (6%), and severe hypertension (1%). Factors that independently predicted rehospitalization were low exercise capacity (p = 0.02) and the presence of diabetes (chi-square 4.8, p = 0.03). Diabetes was also associated with more episodes of hospital admission (2.3 +/- 2.1 vs 1.6 +/- 1.4, p = 0.04) and a longer cumulative hospital stay (25.5 +/- 34.6 vs 11.4 +/- 19.6 days, p = 0.02). Thus, in patients with MI or after PTCA receiving conventional medical therapy, the cardiac rehabilitation program should focus on aggressive diabetic control and enhancement of exercise capacity.

Aged↗
PubMed2000

Diastolic blood pressure is related to urinary sodium excretion in hypertensive Chinese patients.

We studied 70 Hong Kong Chinese patients with untreated hypertension and 47 normotensive controls. Blood pressure measurements and 24-h urine collection were performed for each patient, and were repeated 12 weeks later in 14 hypertensive patients who remained untreated. Twenty-two hypertensive patients underwent ambulatory blood pressure monitoring. The primary hypothesis tested was a correlation between diastolic blood pressure and 24-h urinary sodium excretion. In the hypertensive patients, diastolic blood pressure correlated with 24-h urinary sodium excretion (r=0.41, p<0.001), even after adjustment for age, gender, body mass index, ethanol intake and season (r=0.34, p=0.02). In normotensive controls, diastolic blood pressure did not correlate with sodium excretion (r=0.21, p=0.16). A correlation between diastolic blood pressure and sodium excretion was also observed in the patients who underwent ambulatory blood pressure monitoring (r=0.47, p=0.026), and in repeat measurements in untreated patients (r=0.60, p=0.02). Systolic blood pressure did not correlate with sodium excretion, although it increased with patient age (0.6+/-0.1 mmHg/year, p<0.001). In a multiple regression analysis with diastolic blood pressure as the dependent variable, the regression coefficient was 0.06+/-0.02 mmHg/mmol Na. The regression coefficients for ambulatory diastolic blood pressure and diastolic pressure repeated at 12 weeks were 0.07+/-0.03 and 0. 09+/-0.04 mmHg/mmol Na, respectively. Urinary sodium excretion was related to diastolic blood pressure in our hypertensive patients, accounting for 17% of the variance of diastolic blood pressure.

Adolescent↗
PubMed1999

HpaII polymorphism in the atrial natriuretic peptide gene and hypertension.

This was an association study of genetic polymorphisms to compare the distribution of the genotypes and alleles of the HpaII polymorphism of the atrial natriuretic peptide (ANP) gene in hypertensive patients and normotensive controls. The setting was an outpatient clinic run by a University Department handling referrals from primary care. The patient cohort was composed of 217 subjects, consisting of 109 healthy controls and 108 patients with newly diagnosed or documented hypertension. The genomic DNA was extracted from peripheral blood leukocytes, amplified by polymerase chain reaction, and digested with the restriction enzyme HpaII. H1 and H2 alleles were identified after electrophoresis. The main outcome measures were to identify the frequencies of ANP genotypes and alleles in hypertensive patients and normotensive controls. The H1H1, H1H2, and H2H2 genotypes occurred in 1%, 19%, and 80% of controls and 3%, 18%, and 80% of hypertensive patients, respectively. The frequencies of the H1 and H2 alleles were 0.11 and 0.89 in controls and 0.12 and 0.88 in hypertensive patients. The frequencies of the ANP genotypes and alleles did not differ significantly between controls and hypertensive patients. Our findings differed from previous reports and suggested that this polymorphism is not associated with hypertension in this population.

Adult↗
PubMed1999

Fosinopril reduces left ventricular mass in untreated hypertensive patients: a controlled trial.

AIMS: Left ventricular hypertrophy is a powerful predictor of cardiovascular morbidity and mortality. We tested the hypothesis that fosinopril, an angiotensin-converting enzyme inhibitor, reduces left ventricular mass in hypertensive patients. METHODS: Thirty-three patients with untreated mild essential hypertension were randomised to treatment with oral fosinopril (10 mg-20 mg daily) or placebo for 12 weeks. The primary outcome measure was the change in left ventricular mass index determined by echocardiography. RESULTS: Diastolic blood pressure changed from 95.5+/-2.1 mmHg at baseline to 96.6+/-2.8 mmHg at the final visit in control patients and changed from 96.6+/-2.3 mmHg to 91.5+/-3.0 mmHg in patients treated with fosinopril (P= 0.04). Systolic blood pressure changed from 147.4+/-3.2 mmHg at baseline to 152.7+/-4.4 mmHg at the final visit in control patients and changed from 157.6+/-5.1 mmHg to 149.1+/-6.1 mmHg in patients treated with fosinopril (P=0.02). Fosinopril reduced diastolic pressure by 6.3 (95%CI 0.3-12.4) mmHg and systolic pressure by 13.3 (95%CI 2.7-23.8) mmHg compared with placebo. The left ventricular mass index changed from 110.0+/-8.3 gm(-2) to 113.1+/-8.7 g m(-2) in the control patients and changed from 120.8+/-5.8 g m(-2) to 109.0+/-7.5 g m(-2) in patients treated with fosinopril (P=0.02). Fosinopril reduced left ventricular mass index by 14.9 (95%CI 2.2-27.6) g m(-2) compared with placebo. There was no significant change in the left ventricular systolic or diastolic function, nor were there any significant changes in plasma electrolytes and renal function. CONCLUSIONS: Treatment with fosinopril for 12 weeks reduced left ventricular mass significantly in hypertensive patients.

Adult↗
PubMed1998

M235T polymorphism of the angiotensinogen gene and hypertension in Chinese.

OBJECTIVES: To compare the distributions of the genotypes and alleles of the M235T polymorphism of the angiotensinogen gene for hypertensive patients and normotensive controls. DESIGN: A study of association of genetic polymorphisms. SETTING: An outpatient clinic run by a university department handling referrals from primary care. PATIENTS: Two hundred and four subjects, 103 normal controls and 101 patients with newly diagnosed or documented hypertension. METHOD: Genomic DNA was extracted from peripheral blood leucocytes, amplified by polymerase chain reaction and digested with the restriction enzyme Tth 111 I. Methionine (M) and threonine (T) alleles were identified after electrophoresis. MAIN OUTCOME MEASURES: Prevalences of angiotensinogen genotypes and alleles for hypertensive patients and controls. RESULTS: MM, TM and TT genotypes occurred in 3, 24 and 73% of controls and 1, 22 and 77% of hypertensive patients, respectively. The prevalences of the M and T alleles were 0.15 and 0.85 among controls and 0.12 and 0.88 among hypertensive patients. The prevalences of the angiotensinogen genotypes and alleles for controls and hypertensive patients did not differ significantly. CONCLUSIONS: Our findings differed from previous reports and suggested that this polymorphism is not associated with hypertension in this population.

Adult↗
PubMed1998

Decrease with age in frequency of the homozygous deletional angiotensin-converting enzyme genotype in hypertensive patients.

1. Angiotensin-converting enzyme (ACE) genotypes in hypertensive patients were studied in order to delineate their cardiovascular risk due to the ACE gene. We hypothesized that the distribution of ACE genotypes may change with age because of the risk of myocardial infarction associated with the homozygous deletional (DD) genotype. 2. A total of 223 subjects were recruited from the Hypertension Outpatient Clinic of the Sai Ying Pun Hospital with consent. They consisted of 75 patients with newly diagnosed or documented hypertension, 46 patients with ischaemic heart disease and 102 normal controls. Genomic DNA was extracted from peripheral leucocytes and amplified by polymerase chain reaction. Insertion (I) or deletion (D) alleles were identified after electrophoresis. The frequencies of ACE genotypes and alleles were measured in three age groups: < 50 years, 50-59 years and > or = 60 years. 3. A significant correlation between ACE genotype and age was found (P = 0.03). The relative frequency of the D allele in those under 50 years of age was similar in controls and hypertensive patients (0.40 vs 0.41; P = 0.94), but was significantly lower in patients > or = 50 years compared with those patients < 50 years of age (0.22 vs 0.41; P = 0.01). 4. The observed decrease in frequency of the DD genotype in older hypertensive patients is consistent with the increase in cardiovascular risk associated with the D allele and raises the possibility that the DD genotype may increase the risk of premature death, at least in the population studied.

Aging↗
PubMed1997

Plasma concentration of brain natriuretic peptide is related to diastolic function in hypertension.

1. The plasma brain natriuretic peptide (BNP) concentration is elevated in patients with essential hypertension and normal systolic function. This may be related to left ventricular hypertrophy or diastolic dysfunction, both of which commonly occur in hypertension. 2. Echocardiography was performed on 32 patients with newly diagnosed untreated mild-to-moderate hypertension (19 men, 13 women; mean +/- SD age 51 +/- 15 years; diastolic blood pressure 99 +/- 12 mmHg; systolic blood pressure 153.2 +/- 18.0 mmHg; plasma creatinine 86 +/- 15 mumol/L; creatinine clearance 92.2 +/- 20.5 mL/min; left ventricular mass index 116 +/- 28 g/m2; left ventricular ejection fraction 66 +/- 9%). A 15 mL peripheral venous blood sample was obtained at the time of echocardiography for radioimmunoassay of BNP. 3. Sixteen patients had abnormal Doppler transmittal flow (E/A ratio < 1) and a higher median plasma BNP concentration compared with those patients with E/A > or = 1 (12.9 vs 5.9 pmol/L, respectively; P = 0.006). The plasma BNP level correlated significantly with E/A ratio (r = -0.50; P = 0.035). Multivariate analysis showed that the E/A ratio is related to plasma BNP, independent of age and blood pressure. 4. Our results suggest that the plasma BNP level is influenced by diastolic dysfunction. Further studies are needed to determine whether assay of plasma BNP helps to identify patients with diastolic dysfunction.

Adult↗
PubMed1996

Relative efficacy and tolerability of lacidipine and amlodipine in patients with mild-to-moderate hypertension: a randomized double-blind study.

Calcium channel blockers are increasingly used in the treatment of hypertension. Newer calcium channel blockers of the dihydropyridine group have longer elimination half-lives (t1/2) that permit once-daily dosage and are generally better tolerated than their parent compound. In this study, the efficacy and safety of lacidipine and amlodipine were compared in 65 patients with mild-to-moderate hypertension attending the hypertension outpatient clinic of a teaching hospital in a randomized double-blind cross-over trial with dose titration. Lacidipine and amlodipine both significantly reduced systolic blood pressure (SBP: by 19.2 +/- 13.5 and 22.3 +/- 15.3 mm Hg, respectively) and diastolic BP (DBP: 13.3 +/- 4.2 and 12.3 +/- 5.3 mm Hg, respectively) 24 h postdose. There were no significant differences in their antihypertensive effects. The incidence of adverse events (AE) was 3% for lacidipine and 8% for amlodipine. The incidence of withdrawal from the study due to side effects was 0% for lacidipine and 3% for amlodipine. These results suggest that lacidipine is well-tolerated, and is as effective as amlodipine as a once-daily antihypertensive agent.

Adult↗
PubMed1995

Collagen induces cytokine production by synovial fluid mononuclear cells in rheumatoid arthritis.

Synovial fluid (SF) mononuclear cells (MNC) from 13 patients with rheumatoid arthritis (RA) and 12 patients with other arthritic diseases (OD) including osteoarthritis (OA), gout and spondyloarthritis (SA) were cultured in the presence of collagen types I and II or lipopolysaccharide (LPS) for 24 h. Interleukin-1 (IL-1), IL-6 and tumor necrosis factor-alpha (TNF-alpha) in the SF and culture supernatants were assayed using ELISA. The results showed that one-half of the RA patients with high SF monocyte count had high SF IL-6 levels that coincided with the high spontaneous release of IL-6 by SF MNC. In the other RA patients with lower SF monocyte count, type II collagen induced significantly higher IL-1 beta than the medium control levels by SF MNC (P < 0.01) or that of the other diseases (P < 0.01). Similarly, type II collagen-induced IL-6 and TNF-alpha production rose significantly (P < 0.01) from SF MNC of RA but less from OD (P < 0.05). In addition, type I collagen could also induce IL-1, IL-6 and TNF-alpha in these samples from RA and OD patients but was less potent than type II collagen. Our results indicate that collagen-induced cytokines may be important in the pathogenesis of the disease.

Arthritis, Rheumatoid↗