PubMed Health⌕ Search

Biomedical subjects

B M Cheung

Publications and source records attributed to B M Cheung.

28 records · Page 2Linked to original sources
PubMed1994

Effects of physiological increments in human alpha-atrial natriuretic peptide and human brain natriuretic peptide in normal male subjects.

1. Brain natriuretic peptide, closely related to atrial natriuretic peptide in structure, may be an important circulating hormone. Its physiological role is unclear. First, we studied the effects of incremental infusions of brain natriuretic peptide in six healthy men on plasma brain natriuretic peptide levels and the pharmacokinetics of brain natriuretic peptide. Synthetic human brain natriuretic peptide-32 was infused intravenously, at an initial rate of 0.4 pmol min-1 kg-1, doubling every 15 min until the dose rate reached 6.4 pmol min-1 kg-1, at which rate the infusion was maintained for 30 min. 2. The brain natriuretic peptide infusion raised the brain natriuretic peptide-like immunoreactivity from 1.4 +/- 0.5 pmol/l to 21.4 +/- 7.6 pmol/l. Brain natriuretic peptide-like immunoreactivity after the end of infusion was consistent with a bi-exponential decay, with half-lives of 2.1 min and 37 min. 3. Next, we studied the effects of low-dose infusion of brain natriuretic peptide to mimic physiological increments in the circulating levels in comparison with atrial natriuretic peptide. Six dehydrated male subjects received intravenous infusions of atrial natriuretic peptide and brain natriuretic peptide, separately and in combination, in a randomized double-blind, placebo-controlled, four-part cross-over design. Atrial natriuretic peptide and brain natriuretic peptide were given at the rate of 0.75 and 0.4 pmol min-1 kg-1, respectively, for 3 h. The control infusion consisted of the vehicle. 4. Analysis of variance showed that atrial natriuretic peptide and atrial natriuretic peptide plus brain natriuretic peptide, but not brain natriuretic peptide alone, increased urinary flow and decreased urinary osmolality significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Plasma brain natriuretic peptide and C-type natriuretic peptide in essential hypertension.

OBJECTIVES: To study the relationship between hypertension and the plasma levels of brain natriuretic peptide (BNP) and C-type natriuretic peptide (CNP), and to determine whether the plasma levels of BNP and CNP are correlated. DESIGN: A cross-sectional study of the plasma levels of BNP and CNP in hypertensive patients and normotensive controls matched for age and sex was performed. SETTING: The hypertension research clinic in a teaching hospital and well-person risk factor screening clinics in general practice health centres. PARTICIPANTS: Fifty-four subjects (29 hypertensive, 25 normotensive controls) took part in the study after giving their informed consent. Hypertensive patients (n = 19) were paired with normotensive controls (n = 19) matched for age and sex to form a subgroup before analysis of the plasma. METHODS: The plasma levels of BNP and CNP were determined by specific radioimmunoassays. RESULTS: The mean plasma concentration of BNP was significantly higher in the hypertensive group than in the paired controls. In contrast, the mean plasma concentration of CNP was not significantly different in the hypertensive group than in the paired controls. Multiple regression analysis of all 54 subjects showed that the plasma level of BNP correlated significantly with age and systolic blood pressure, whereas the plasma level of CNP correlated significantly with sex, heart rate and alcohol intake. The CNP levels did not correlate significantly with either systolic or diastolic blood pressure, or with plasma brain natriuretic levels. CONCLUSIONS: Hypertension is associated with raised BNP but not CNP plasma levels.

Aging↗
PubMedDate not supplied

Amlodipine, felodipine, and isradipine in the treatment of Chinese patients with mild-to-moderate hypertension.

Optimal treatment of hypertension requires the use of effective antihypertensive drugs. Calcium channel blockers are widely used in the treatment of hypertension and appear to be particularly efficacious in ethnic Chinese patients. The aim of this open-label study was to prospectively investigate the efficacy and tolerability of three dihydropyridine calcium channel blockers in sequence, using the same protocol for each. After 2 weeks of placebo treatment, 73 males and 45 females (mean age, 45 +/- 10 years; mean weight, 67 +/- 10 kg) with essential hypertension (diastolic blood pressure, 95 to 115 mm Hg) were treated with amlodipine (n = 41), felodipine (n = 38), or isradipine (n = 39) for 8 weeks, with dose titration after 4 weeks. Mean seated systolic and diastolic blood pressure decreased by 23/17, 30/17, and 20/15 mm Hg after 8 weeks of treatment with amlodipine, felodipine, and isradipine, respectively. These reductions were all statistically significant. Blood pressure was controlled (defined as diastolic pressure < 90 mm Hg at the final visit or a decrease from baseline of > or = 10 mm Hg) in 85%, 74%, and 74% of patients receiving amlodipine, felodipine, and isradipine, respectively. There were no significant changes in heart rate, plasma lipid levels, or serum biochemistry markers with any of the three treatments. No serious adverse events occurred, but mild adverse effects, including headaches, flushing, tachycardia, dizziness, and edema, were reported; 1 (2%), 6 (16%), and 5 (13%) patients receiving amlodipine, felodipine, and isradipine, respectively, withdrew from the study (P < 0.05). The results of this study indicate that all three drugs are highly effective in lowering blood pressure and are well tolerated in Chinese patients with mild-to-moderate hypertension.

Adolescent↗
PubMedDate not supplied

Comparison of digoxin versus low-dose amiodarone for ventricular rate control in patients with chronic atrial fibrillation.

1. Rapid ventricular rate (VR) and rhythm irregularity during atrial fibrillation (AF) impair cardiac performance. Although digoxin has been widely used in patients with AF, its efficacy for the control of VR and rhythm irregularity is unsatisfactory. Whether low-dose amiodarone is more effective remains unclear. 2. We randomized 16 patients (13 male, three female; mean (+/-SD) age 63 +/- 9 years) with chronic AF to receive either digoxin or amiodarone for 24 weeks. At baseline and at 12 and 24 weeks follow up, Holter monitor recording and cardiopulmonary exercise test were performed to assess VR and rhythm irregularity control and exercise capacity. 3. Seven and nine patients received digoxin and amiodarone, respectively. After 12 and 24 weeks treatment, both digoxin and amiodarone significantly decreased the mean ambulatory VR and the VR during peak exercise compared with baseline (all P < 0.05). At 24 weeks, there were no significant differences between digoxin and amiodarone in the percentage reduction in VR during ambulatory (27 +/- 13 vs. 25 +/- 12%, respectively; P = 0.8) and peak exercise (13 +/- 12 vs. 12 +/- 10%%, respectively; P = 0.6). 4. The rhythm irregularity, as measured by SD of RR intervals and the root mean square of the SD of RR intervals, and the exercise capacity, as measured by exercise workload, maximal oxygen consumption (VO2), minute ventilation, ventilatory equivalent and oxygen pulse, were not significantly changed after treatment with digoxin or amiodarone (all P > 0.05). 5. Quality of life, determined by SF-36 questionnaire, and AF symptomatology, as measured by the AF Symptom Checklist, were also not significantly changed after treatment with digoxin or amiodarone (all P > 0.05). 6. In conclusion, digoxin and low-dose amiodarone had similar efficacy in the control of VR during ambulatory activity and exercise. However, both were less efficacious during exercise and did not significantly affect rhythm irregularity, exercise capacity, quality of life and AF symptomatology in patients with chronic AF.

Aged↗
PubMedDate not supplied

Screening for diseases in elderly persons: the correlation between physical checkup findings and chief complaints.

BACKGROUND: The effectiveness of a physical checkup program for screening for diseases in the elderly, in terms of correlation with their chief complaints has not been previously evaluated. OBJECTIVE AND METHODS: The study was to examine the correlation between physical checkup findings and chief complaints of elderly people. Study subjects were over 65 years of age. There were 792 males and 373 females. They all attended a 2-day physical checkup program at Taichung Veterans General Hospital from January 1, 1994, to December 31, 1995. RESULTS: The results showed a significant difference (p<0.05) between male (12.0%) and female (16.8%) subjects in the relationship of clinical findings to chief complaints. When the locations of chief complaints were compared, those concerning the neck and the limbs corresponded well to our clinical findings. However, there were differences between female and male subjects (42.4 and 24.4%, respectively; p<0.01) in this aspect. There was a good relationship (p<0.05) between physical checkup findings and complaints of lower back pain (75.2%), upper abdominal pain (46.2%) and knee joint pain (38.3%). However, we found that 43.7% of physical checkup findings were not linked to chief complaints. CONCLUSIONS: The results suggest that additional appropriate clinical tests may improve the effectiveness of physical checkups and thus result in health benefits for elderly persons.

Abdominal Pain↗