Interethnic differences in coronary heart disease mortality in 25 populations: association with the angiotensin-converting enzyme DD genotype frequency

BACKGROUND

Despite changes in dietary habits and steadily increasing serum cholesterol concentrations, coronary heart disease (CHD) mortality rates in developed South-East Asian populations are still one quarter those in many Western populations. We propose that genetic factors may, in part, contribute to these differences in CHD mortality.

DESIGN

Using an ecological study design, we have investigated the comparative roles of serum cholesterol concentration and the angiotensin-converting enzyme (ACE) homozygote deletion (DD) genotype frequency, which has recently been implicated in CHD mortality.

METHODS

Using our genotyping data from local Chinese populations, together with previously published data on ACE gene frequency and cholesterol concentrations, we correlated ACE DD genotype frequencies and mean serum cholesterol concentrations with World Health Organization age-adjusted CHD mortality rates in 25 ethnically diverse populations.

RESULTS

Although mean serum cholesterol accounted for 67% of the variance in CHD mortality rates for all populations (r=0.82, 95% Cl 0.63-0.92, n=25, P<0.001), the ACE DD frequency accounted for 61% of the variance in 'low' cholesterol populations (r=0.78, 95% Cl 0.43-0.91, n= 14, P<0.001) with no additional contribution from serum cholesterol concentration. Moreover, in the 'low' cholesterol population, mean serum cholesterol accounted for only 37% of the variance.

CONCLUSION

We hypothesize that differences in the frequency of the ACE DD genotype in populations with low mean serum cholesterol concentrations may play some part in determining interethnic differences in CHD mortality rates.

Mutations in the low-density lipoprotein receptor gene in Chinese familial hypercholesterolemia patients

It has been reported that in China, patients with heterozygous familial hypercholesterolemia (FH) may go unrecognized because they do not have xanthomata or premature coronary heart disease and their LDL cholesterol levels are lower than those in their Western counterparts. However, in the Chinese patients in Hong Kong, heterozygous FH appears to manifest in a way similar to that seen in Western countries or Japan. We studied sequence variations in the promoter and coding regions of the 18 exons of the LDL receptor gene in 30 Chinese FH patients. Eighteen mutations were identified in 21 patients scattered in the promoter and 10 exons. Eleven of them were first found in this study. We also found 6 polymorphisms with allelic frequencies different from those in whites but similar to the Japanese, indicating some isolation between white and Oriental populations. A total of 29 mutations in the LDL receptor gene are now known in the Chinese. There is no definite common mutation due to a founder effect. Meanwhile, there were no detectable LDL receptor gene mutations in 9 clinically diagnosed FH patients in whom the R3500Q mutation in apolipoprotein B had also been excluded. The gene defects leading to the FH phenotype in these patients may occur somewhere else in the apolipoprotein B or other related genes, or even in the noncoding sequences of the LDL receptor gene.

Caco-2 cell permeability of a new (hydroxybenzyl)ethylenediamine oral iron chelator: correlation with physicochemical properties and oral activity

This study describes the transport of CGP 75254A, a novel oral iron chelator, across Caco-2 cells in an attempt to model intestinal epithelial cell permeability in man. CGP 75254A was dosed to the apical side of Caco-2 cell monolayers, together with [14C]mannitol as an internal permeability standard. The apparent permeability (Papp) was calculated from the cumulative appearance of drug in the basolateral fluid with time. The [14C]mannitol Papp indicated that the Caco-2 monolayers remained intact and that the iron chelator was not toxic to the cells. Permeabilities of CGP 75254A were compared with the Caco-2 permeabilities of compounds of known absorption in man. The results predict that absorption of CGP 75254A is likely to be virtually complete at pH values between 5.5 and 7.0. However, at pH 8.0 permeability is predicted as negligible. Cell permeability data are in full accordance with key physicochemical properties of CGP 75254A and suggest that the drug is passively absorbed. The results, which suggest likely quantitative absorption in vivo, are supported by preliminary pharmacological experiments in marmosets.

Hyperlipidaemia in Chinese populations

Chinese populations have been protected from coronary heart disease by a low fat diet and low plasma lipids. Fat intake has increased in more affluent populations but coronary heart disease mortality has remained relatively low. Further increases in dietary fat in young people and rising rates of diabetes in the older population may increase the prevalence of hyperlipidaemia and vascular disease.

Acute effects of a surgical menopause on serum concentrations of lipoprotein(a)

OBJECTIVE

The aim of this study was to investigate acute changes in serum concentrations of lipoprotein(a) and other atherogenic lipids and lipoproteins after a surgical menopause.

METHODS

A total of 100 premenopausal Chinese women who were booked for hysterectomy for benign gynecological disorders were recruited. They study group comprised 40 subjects undergoing hysterectomy as well as bilateral oophorectomy. The control group consisted of 60 subjects undergoing hysterectomy with conservation of the ovaries. Complete data were available from 30 of the 40 subjects in the study group and from 44 of the 60 controls. Serum concentrations of lipoprotein(a) and other atherogenic lipids and lipoproteins were measured before surgery and these measurements were repeated 3 days, 8 weeks and 6 months postoperatively. Those study patients who received hormone replacement therapy and control patients who became menopausal, according to biochemical criteria, during the study period were excluded from analysis.

RESULTS

Three days after surgery, there was a significant increase in the mean lipoprotein(a) concentration in the control group from 19.1 to 23.0 mg/dl (p < 0.01), but there was no significant change in the study group. There were no significant changes from baseline in the mean lipoprotein(a) concentration in either group 8 weeks or 6 months after surgery. There was a significant increase in the mean concentration of total cholesterol in the study group 8 weeks after surgery from 5.08 to 5.45 mmol/l (p < 0.01), in low density lipoprotein cholesterol from 3.22 to 3.49 mmol/l (p < 0.01), and in apolipoprotein B from 95.6 to 103.0 mg/dl (p < 0.05). However, the mean concentrations 6 months after surgery were not significantly different from baseline levels. The mean concentrations of high density lipoprotein cholesterol, apolipoprotein A-1 and triglycerides also did not differ significantly from baseline in the study group, either 8 weeks or 6 months after surgery.

CONCLUSIONS

These results suggest that any increase in concentrations of lipoprotein(a), and other atherogenic lipids and lipoproteins which occur after the menopause, develops relatively slowly. The changes in concentrations which occurred within 8 weeks of surgery were probably an acute-phase reaction after surgery rather than a response to a decreasing estradiol concentration.

Antioxidant power of angiotensin-converting enzyme inhibitors in vitro

AIMS

There is controversy regarding the potential antioxidant effect of captopril, therefore this study was performed to compare the in vitro antioxidant power of captopril with other angiotensin-converting enzyme (ACE) inhibitors.

METHODS

Antioxidant power of captopril, enalapril, fosinopril, perindopril, quinapril and ramipril in aqueous solution was measured using the ferric reducing (antioxidant) power (FRAP) assay; captopril was also measured in ethanolic solution.

RESULTS

Only captopril showed significant antioxidant power, demonstrating a stoichiometric factor of 1.0 in this assay. Concentration-related antioxidant power was seen in both aqueous and ethanolic solutions.

CONCLUSIONS

Captopril shows antioxidant activity in vitro. This property could be relevant in vivo if captopril is concentrated in membranes, lipoproteins or at other important sites.

A prescription survey in a hospital hypertension outpatient clinic

AIMS

The objective of this study was to investigate drug utilization in the management of hypertension in Hong Kong.

METHODS

We conducted a prescription survey to examine the use of antihypertensive drugs in a hypertension clinic in a regional hospital and the resulting expenditure incurred. The use of concurrent medications such as antidiabetic drugs and lipid-lowering agents was also examined.

RESULTS

During a 7-week study period, 530 prescriptions were collected. All except 14 patients received antihypertensive drugs with 262 (50.8%) on monotherapy and 254 (49.2%) on combination therapy. Calcium channel blocking agents and beta-adrenoceptor blocking agents were the two most popular antihypertensive drugs used in both monotherapy (38% and 31%, respectively) and combination therapy (27% and 33%, respectively). Forty-nine patients (19%) received three antihypertensive drugs or more. The number of antihypertensive drugs showed a significant positive correlation with the duration of attendance at the clinic (r=0.88, P < 0.001). Of the total 530 prescriptions, 5.6% and 10% contained antidiabetic drugs and lipid-lowering agents, respectively. Calcium channel blocking agents, angiotensin converting enzyme (ACE) inhibitors and lipid lowering agents, accounted for 82% (HK$211,654; pounds sterling 1 approximately HK$12) of the total drug expenditure (HK$258,115). Seventy-nine percent of the lipid lowering agents prescribed were hydroxymethylglutaryl coenzyme A (HMG CoA) reductase inhibitors. Amlodipine accounted for 26% of usage but contributed to 41% of the overall costs of calcium channel blocking agents. Alpha1-adrenoceptor blocking agents were only used infrequently and were the most expensive class of drugs, due to the preferred use of doxazosin rather than prazosin which is far cheaper than the former.

CONCLUSIONS

In view of the use of these often costly drugs for long-term therapy, monitoring of their use and its correlation with clinical outcomes and quality of life is essential to ensure the optimal use of health care resources.

New insights into the treatment of hypertension

1. The choice of initial pharmacological therapy is one area where the different hypertension management guidelines vary in recommending either the use of diuretics and beta-blockers as preferred drugs or choosing from any of the five major classes of antihypertensives. 2. Improvement in cardiovascular morbidity and mortality may have been shown most conclusively with diuretics and beta-blockers, but the effects on coronary events with these drugs were less than predicted and the other agents have a number of theoretical advantages. 3. Recent worries regarding the possible adverse effects of calcium antagonists have led to a reappraisal of the risks and benefits of these drugs and antihypertensives in general. 4. Many patients, particularly the elderly, have other conditions that influence the choice of first-line therapy and ethnic variations in the effects of hypertension or the efficacy or side effects of drugs should also be taken into account. 5. There is considerable heterogeneity within the major categories of antihypertensive drugs, so it is important to distinguish the different subgroups, dosages and formulations that may be used.

Visceral fat and cardiovascular risk factors in Chinese NIDDM patients

OBJECTIVE

The interrelations between obesity, glucose intolerance, hypertension, dyslipidemia, and insulin resistance are well recognized. These relationships are of particular interest in Hong Kong's Chinese population, in whom increasing affluence has coincided with a marked increase in the prevalence of NIDDM. We designed a pilot study to examine the relationships between visceral fat and cardiovascular risk factors in Chinese NIDDM patients.

RESEARCH DESIGN AND METHODS

We studied 21 Chinese NIDDM patients whose visceral fat was quantified by magnetic resonance imaging. Cardiovascular risk factors including plasma lipids and 24-h ambulatory blood pressure (BP) were measured. In addition, insulin resistance was determined by a short insulin tolerance test (SITT).

RESULTS

Increased visceral adiposity was significantly correlated with plasma triglycerides (r = 0.63, P = 0.004), the total cholesterol/HDL cholesterol ratio (r = 0.61, P = 0.008), the urinary albumin/creatinine ratio (r = 0.49, P = 0.04), and decreased insulin sensitivity as measured by the SITT (r = 0.47, P = 0.03). When the data were analyzed by tertiles, increasing visceral fat area was associated with higher plasma triglycerides, lower HDL cholesterol, and a smaller plasma glucose decrement during the SITT. In addition, the diurnal rhythm in BP and heart rate tended to be best preserved in those with the least visceral obesity.

CONCLUSIONS

This pilot study demonstrates that visceral fat accumulation is associated with dyslipidemia, hypertension, insulin resistance, and albuminuria in Chinese patients with NIDDM.

Myocardial protective effect of trilinolein: an antioxidant isolated from the medicinal plant Panax pseudoginseng

In a previous study we demonstrated that trilinolein, a natural plant triacylglycerol, is a novel myocardial protective agent in vivo. The mechanism probably involves an antioxidant effect. This work investigated the mechanism of myocardial protection of trilinolein to determine if inhibition of calcium influx and alteration of activity of superoxide dismutase are involved. In isolated cardiomyocytes, pretreatment with trilinolein at a low concentration of 10(-9) M effectively reduced 45Ca2+ influx stimulated by hypoxia/normoxia by 34%. In isolated perfused rat heart subjected to 60 min global hypoxemia without reperfusion, pretreatment with 10(-7) M trilinolein for 15 min reduced infarct size by 37%. Assay of superoxide dismutase-mRNA by Northern blot analysis in in vivo rat heart subjected to 30 min ischaemia and 10 min reperfusion showed pretreatment with 10(-7) M trilinolein had a synergistic action with antioxidant systems preventing the rise in superoxide dismutase-mRNA. These results reconfirm the myocardial protection of trilinolein and suggest it may be related to antioxidant activity and inhibition of 45Ca2+ influx.

Effect of trilinolein on superoxide dismutase activity and left ventricular pressure in isolated rat hearts subjected to hypoxia and normoxic perfusion

Oxygen-derived free radicals have been implicated in the development of myocardial injury during hypoxia/reperfusion. Antioxidants can effectively inhibit the formation of free radicals and ameliorate the myocardial damage which may occur during hypoxia/reperfusion. Trilinolein is a triacylglycerol recently purified from the traditional Chinese medicinal plant Panax pseudo-ginseng. It has linoleic-acid residues as the only type of fatty acid residue in all three esterified positions of the triacyglycerol. It has been proposed that decreased endogenous superoxide dismutase (SOD) activity may contribute to free radical-mediated reperfusion injury of the ischemic myocardium. In the present study, when isolated rat hearts were subjected to hypoxia for 10, 30, 60 and 90 min without normoxic perfusion, a significant decrease in Mn-SOD activity was shown throughout the period of hypoxia, whereas the Cu.Zn-SOD activity was increased at 10 and 30 min but was not different from the baseline at 60 and 90 min of hypoxia. In rat hearts pretreated with 10(-7) mol/l trilinolein and subjected to 60 min of hypoxia without normoxic perfusion, Cu.Zn-SOD was augmented compared with baseline and compared with hearts subjected to 60 min of hypoxia without trilinolein, whereas Mn-SOD activity was still reduced compared with baseline, although less so than after 60 min of hypoxia without trilinolein. Pretreatment with trilinolein was associated with better preservation of left ventricular function during hypoxia and more rapid return to recovery during normoxic perfusion. This myocardial protective effect may be related to an antioxidant effect through potentiation of SOD, particularly Cu.Zn-SOD during hypoxia.

Efficient high-performance liquid chromatographic assay for the simultaneous determination of metoprolol and two main metabolites in human urine by solid-phase extraction and fluorescence detection

An improved, more efficient method for the determination of metoprolol and its two metabolites in human urine is reported. The simultaneous analysis of the zwitterionic metoprolol acidic metabolite (III, H117/04) with the basic metabolites alpha-hydroxymetoprolol (II, H119/66), metoprolol (I) and guanoxan (IV, internal standard) was achieved employing solid-phase extraction and isocratic reversed-phase HPLC. The analytes were extracted from urine (100 microliters) using C18 solid-phase extraction cartridges (100 mg), and eluted with aqueous acetic acid (0.1%, v/v)-methanol mixture (40:60, v/v, 1.2 ml). The eluents were concentrated (250 microliters) under vacuum, and aliquots (100 microliters) were analysed by HPLC with fluorescence detection at 229 nm (excitation) and 309 nm (emission) using simple isocratic reversed-phase HPLC (Novapak C18 radial compression cartridge, 4 microns, 100 x 5 mm I.D.). Acetonitrile-methanol-TEA/phosphate buffer pH 3.0 (9:1:90, v/v) was employed as the eluent (1.4 ml/min). All components were fully resolved within 18 min, and the calibration curves for the individual analytes were linear (r2 > or = 0.996) within the concentration range of 0.25-40.0 mg/ml. Recoveries for all four analytes were greater than 76% (n = 4). The assay method was validated with intra-day and inter-day variations less than 2.5%.

Additive effects of diltiazem and lisinopril in the treatment of elderly patients with mild-to-moderate hypertension

A multicenter, double-blind, placebo-controlled trial with multifactorial design was conducted to evaluate the safety and efficacy of the calcium-channel blocker diltiazem, in a sustained release preparation, and the angiotensin converting enzyme inhibitor, lisinopril, in the treatment of elderly Chinese patients with mild-to-moderate hypertension. In addition to the hypotensive effects of combinations of both drugs compared with monotherapy, all given once daily, the effect on quality of life was also evaluated. This study consisted of a 3 x 2 multifactorial design in which 156 women and men with a sitting diastolic pressure of between 95 mm Hg and 114 mm Hg, after a 4-week placebo washout phase, were randomized to one of six treatment groups for 12 weeks of active treatment. Monotherapy with diltiazem 120 or 240 mg produced increasing reductions of systolic and diastolic blood pressure. Compared with placebo, lisinopril 10 mg had an effect intermediate between the diltiazem doses. The combinations of diltiazem 240 mg + lisinopril 10 mg and diltiazem 120 mg + lisinopril 10 mg showed increased efficacy in reducing systolic and diastolic blood pressure compared to these drug doses used in monotherapy, but the effect of the combinations was less than predicted by an additive model. Although the total number of other adverse events reported was similar for all active treatment groups compared to placebo, lisinopril-induced cough was common with an incidence of 31% after rechallenge. Premature drug withdrawal was necessary in four of 78 patients receiving lisinopril, due to intractable cough. The combination of diltiazem 240 mg and lisinopril 10 mg was significantly more effective at reducing blood pressure than either drug alone; this additive effect did not result in a higher rate of adverse effects or impairment of quality of life. Thus, combination therapy with these agents was well tolerated and resulted in increased efficacy in these elderly patients.

Short-term safety and efficacy of low-dose simvastatin in elderly patients with hypertensive hypercholesterolemia and fasting hyperinsulinemia

To evaluate the short-term safety and efficacy of low-dose (10 mg) simvastatin in hypercholesterolemic, hypertensive elderly Chinese patients receiving antihypertensive treatment, a randomized, double-blind, placebo-controlled, 3-month trial was conducted. The patients had a total plasma cholesterol level of at least 250 mg/dL and had been, for at least 3 months, consuming a standard lipid-lowering diet (American Heart Association Step 1 Diet). Elderly hypertensive patients (n = 76) were randomized to receive treatment with either placebo (n = 38) or simvastatin (n = 38). The dosage consisted of 10 mg simvastatin daily during the 3-month trial. During that period, in the simvastatin group, plasma levels of total cholesterol and low-density lipoprotein cholesterol decreased significantly (27% and 33%, respectively) compared with those levels in plasma in the placebo group. The plasma levels of high-density lipoprotein cholesterol increased (7%), whereas triglyceride levels slightly decreased (8%). There were no serious side effects, and simvastatin was generally well tolerated. Fasting hyperinsulinemia also improved (-21%) after 3 months of simvastatin therapy. Results of this study confirmed that a low dose (10 mg) of simvastatin daily is a safe and effective method of reducing plasma levels of total and low-density lipoprotein cholesterol in hypercholesterolemic, hypertensive elderly patients receiving concurrent antihypertensive drug therapy, and that it has the additional potential benefit of reducing plasma levels of insulin.

Non-invasive continuous arterial pressure, heart rate and stroke volume measurements during graded head-up tilt in normal man

The haemodynamic effects of head-up tilt (HUT) at different tilt angles were investigated non-invasively in eight normal male subjects. Mean arterial pressure (MAP; by Ohmeda Finapres 2300), stroke volume (SV) and heart rate (HR; by BoMed NCCOM3-R7S) were continuously recorded whilst performing a series of HUTs (55 degrees, 10 degrees, 20 degrees, 30 degrees and 55 degrees) lasting 3 min each. The response to HUT was proportional to the sinc of the tilt angle. The magnitude of the response varied between subjects. HUT to 55 degrees resulted in mean (95% confidence limits) increases in MAP by 16 (+/-16)% and HR by 11 (+/-24)% and a decrease in SV by -25 (+/-22)%. These results were repeatable after 30 min. At small tilt angles, i.e. < or = 20 degrees, MAP did not change and HR decreased by -3 (+/-4)%. A detailed analysis revealed immediate dynamic (0-30 s), late dynamic (30-90 s) and plateau (after 90 s) phases in the response to HUT. In conclusion, HUT produces reproducible haemodynamic effects, although differences exist among subjects. A detailed analysis of these effects can be successfully performed using non-invasive methods.

Double-blind comparison of losartan, lisinopril, and metolazone in elderly hypertensive patients with previous angiotensin-converting enzyme inhibitor-induced cough

This study compared the incidence of cough with the angiotensin-converting enzyme (ACE) inhibitor lisinopril and the diuretic metolazone with angiotensin II receptor antagonist losartan in elderly hypertensive patients with previous histories of ACE inhibitor-induced cough. A randomized, double-blind, stratified, parallel-group comparison of lisinopril at 10 mg, losartan at 50 mg, and metolazone at 1 mg, each given once daily for a maximum of 10 weeks, was performed in four hypertension clinics in four centers in two countries. Cough was detected by a questionnaire (the primary end point) given to elderly patients with hypertension, and the cough frequency was quantified by a visual analog scale (a secondary end point). A total of 84 elderly patients with hypertension, all who were nonsmokers with ACe inhibitor-induced cough and were confirmed by lisinopril rechallenge then placebo dechallenge, were randomized to the three treatment groups. The incidence of cough with losartan (18%) was significantly lower than with lisinopril (97%) and similar to that for metolazone (21%). Cough frequency evaluated by the visual analog scale was significantly lower for losartan than for lisinopril and similar to that for metolazone. The specific, selective angiotensin II receptor antagonist losartan is associated with a decrease in the incidence of cough in patients with previous ACE inhibitor-induced cough.

Antihypertensive and anti-albuminuric effects of losartan potassium and felodipine in Chinese elderly hypertensive patients with or without non-insulin-dependent diabetes mellitus

After a 4-week placebo baseline period, 29 Chinese elderly hypertensive patients were randomized, double-blind, to 12 weeks of treatment with either losartan potassium (n = 19), an angiotensin II antagonist at the AT1 receptor, or felodipine (n = 10), a calcium channel blocking agent. Of these 29 patients 12 had coexisting non-insulin-dependent diabetes mellitus. At week 12, the mean reductions (95% confidence intervals) in mean arterial pressure were similar in both groups: losartan -18 (range -22 to -14) mm Hg; felodipine -19 (range -25 to -11) mm Hg. In the whole group, the 24-hour urinary albumin excretion was reduced by 27% with losartan as compared with no change in the felodipine-treated group (p = 0.03; analysis of variance). In the diabetic group, losartan treatment reduced the urinary albumin excretion by 24% as compared with 11% in the felodipine-treated group. In the non-diabetic patients, the urinary albumin excretion fell by 29% in the losartan-treated group, but increased by 14% in the felodipine-treated group (p < 0.001; repeated-measures analysis of variance). Plasma sodium increased to a similar extent in both groups. The fasting plasma triglyceride level declined by 25% (p < 0.001 within group) with losartan, but was not significantly reduced in the felodipine-treated group. For comparable reductions in blood pressure, a greater reduction in albuminuria was seen with losartan than with felodipine treatment in Chinese hypertensive patients with or without non-insulin-dependent diabetes mellitus. Long-term studies are required to examine whether these antiproteinuric effects of losartan can be translated to renoprotection.

Beneficial effects of pravastatin on fasting hyperinsulinemia in elderly hypertensive hypercholesterolemic subjects

We undertook this prospective double-blind, placebo-controlled study to evaluate the efficacy and safety of low-dose (15 mg) pravastatin in elderly hypercholesterolemic hypertensive subjects with concurrent antihypertensive treatment and to determine whether fasting hyperinsulinemia could also be improved. At three hypertension and lipid clinics of two medical centers, 96 elderly (49 women, 47 men) ambulatory subjects were randomized to active treatment or placebo for 12 months after a 3-month single-blind lead-in period. Hypertensive subjects with plasma total cholesterol levels of at least 6.47 mmol/L (250 mg/dL) and triglyceride levels less than 3.39 mmol/L (300 mg/dL) were treated with 15 mg pravastatin for 12 months after receiving 3 months of the American Heart Association step I diet. Lipid, glucose, and fasting insulin levels were measured; clinical laboratory tests included liver function and creatine kinase determinations. After 12 months of pravastatin therapy, plasma total cholesterol concentration decreased by 25.1% (from a mean of 7.29 to 5.47 mmol/L, P < .05), low-density lipoprotein cholesterol decreased by 30.2% (from 5.27 to 3.68 mmol/L, P < .05), and triglycerides decreased by 10.7% (from 1.68 to 1.50 mmol/L, P < .05). High-density lipoprotein cholesterol increased by 9.2% (from 1.20 to 1.31 mmol/L, P < .05). Fasting insulin levels decreased from 89.0 to 61.5 pmol/L (P < .05). All of these changes were greater (P < .05) than any tendency toward change in the placebo group. Adverse events and clinical laboratory abnormalities were generally mild and transient in both placebo and pravastatin groups. Study drugs were withdrawn from one subject in each group with asymptomatic creatine kinase elevations. We conclude that low-dose pravastatin was effective and safe in the treatment of hypercholesterolemic hypertensive subjects on concurrent antihypertensive therapy. It also improved fasting hyperinsulinemia despite the use of beta-blockers and diuretics in these hypertensive subjects.

Optimal dosage of ACE inhibitors in older patients

Despite having lower levels of plasma renin activity than younger individuals, elderly patients with hypertension respond well to ACE inhibitors and the drugs have few adverse effects. Plasma concentrations of the active ACE inhibitor are generally higher in the elderly because of decreased renal clearance. These altered pharmacokinetics, combined with impairment of cardiovascular reflexes and the increasing prevalence of heart failure and renal impairment with age, render elderly patients more susceptible to first-dose hypotension. Although many studies have shown that standard dosages are well tolerated it is safer to use lower initial dosages of ACE inhibitors in elderly hypertensive patients because hypotensive reactions are not always predictable. The maintenance dosage may be determined more by the presence of renal disease or heart failure than by age per se. In elderly patients with heart failure, ACE inhibitors should be introduced even more cautiously, using low dosages and preferably under supervision. It may also be necessary to interrupt diuretic treatment for a few days to prevent severe hypotension. The ACE inhibitor dosage should then be titrated up to the maximum that is well tolerated, as this appears to offer the greatest benefit.

Hepatitis related to the Chinese medicine Shou-wu-pian manufactured from Polygonum multiflorum

Hepatitis developed in a 31-y-old pregnant Chinese woman after consumption of Shou-Wu-Pian, a proprietary Chinese medicine prepared from Polygonum multiflorum. Tests for viral hepatitis were negative and there was no evidence of other systemic disease. The herbal preparation is commonly available in the Orient and China towns in western countries. Cases of herb-induced hepatitis reported in China are reviewed.

Impact of changes in respiratory frequency and posture on power spectral analysis of heart rate and systolic blood pressure variability in normal subjects and patients with heart failure

1. Autonomic dysfunction is a major feature of congestive cardiac failure and may have an important role in determining progression and prognosis. The low-frequency/high-frequency ratio derived from power spectral analysis of heart rate variability has been proposed as a non-invasive method to assess sympatho-vagal balance. However, the effects of different respiratory rates or posture are rarely accounted for, but may be relevant in patients with heart failure in whom clinical improvement is accompanied by a fall in respiratory rate and an increased proportion of the day in the upright position. 2. We have assessed the effect of controlled respiration at different rates (10, 15, 20 breaths/min or 0.17, 0.25 and 0.33 Hz), while supine and standing, on power spectral analysis of heart rate and blood pressure variability in 11 patients with heart failure and 10 normal subjects. 3. Heart rate variance and low-frequency power (normalized units) were reduced in patients with heart failure (absent in six). During controlled breathing while supine, the power of the high-frequency component was significantly greater at 10 breaths/min than at 20 breaths/min in patients with heart failure, whether expressed in absolute units (P = 0.005) or percentage of total power (P = 0.03). 4. On standing, controlled breathing in patients with heart failure produced less change in high-frequency power (P = 0.054), but the low-frequency/high-frequency ratio at lower respiratory rates was reduced (P = 0.05). In normal subjects, as expected, respiratory rate had a highly significant effect on high-frequency power. Also, in normal subjects there was the expected increase in heart rate low-frequency power (P = 0.04) moving from supine to standing with an increase in the low-frequency/high-frequency ratio (P = 0.003), while in the patients with heart failure this was absent, reflecting blunted cardiovascular reflexes. 5. Systolic blood pressure low- and high-frequency components and their ratio were significantly affected by respiration (P < 0.03) and change in posture (P < 0.03) in both patients with heart failure and normal subjects, with a significant increase in the low-frequency/high-frequency ratio (P = 0.03) on standing in patients with heart failure, indicating that autonomic modulation of blood pressure is still operating in heart failure. 6. Thus, respiratory rate and changes in posture have a significant effect on measurements derived from spectral analysis of heart rate and blood pressure variability. Studies that use power spectral analysis as a measure of sympatho-vagal balance should control for these variables.

Selective liver enzyme induction by carbamazepine and phenytoin in Chinese epileptics

OBJECTIVE

Anticonvulsant drugs are known inducers of cytochrome P450 liver enzymes and it has been suggested that this induction increases susceptibility to paracetamol-induced hepatotoxicity.

METHODS

We measured the percentage urinary recovery of paracetamol and its metabolites after a dose of 20 mg kg-1, and the excretion of 6 beta-hydroxycortisol as a ratio to urinary free cortisol (6 beta OHF/F) in Chinese epileptic patients maintained on long-term therapy with carbamazepine (n = 6) or phenytoin (n = 6).

RESULTS

Compared to the healthy controls (n = 20), patients on phenytoin had significantly lower recoveries of mercapturic acid, cysteine and sulphate metabolites, but a higher recovery of glucuronide metabolites of paracetamol. The recoveries of paracetamol metabolites in patients on carbamazepine were not different from controls. In contrast, the 6 beta OHF/F was significantly higher in patients on carbamazepine (3-fold) or phenytoin (2-fold) compared to controls. Healthy control Chinese subjects metabolised paracetamol in a similar way to that reported in Caucasians, indicating that the risk for hepatotoxicity would be the same. Our findings in a group of Chinese patients on phenytoin were also similar to those previously reported in Caucasians on this drug. The apparent differences in the pattern of isoenzyme induction between the groups on phenytoin and carbamazepine require verification in larger studies. The data do not suggest an increased risk of paracetamol-induced hepatotoxicity in Chinese patients on anticonvulsants.

Urinary dopamine outputs do not rise in healthy Chinese subjects during gradually increasing oral sodium intake over 8 days

1. All previous studies on the effects of changes in sodium intake on the renal dopamine (DA) response (increase in urinary DA output) have used sudden, large changes in oral sodium intake. The present study was designed to study the role of renal DA and the suppression of sympathetic nervous system activity in the natriuretic response to step-wise, gradual increases in sodium intake. 2. Seven healthy, male Chinese subjects (23-25 years) were studied. During the 12-day study period (day -3 to 8), subjects were given the same basic diet containing 1900 calories, 75 g protein, 20 mmol sodium and 45 mmol potassium. From days 1 to 8, subjects also received 'Slow sodium' tablets (Ciba-Geigy) equivalent to 50 mmol on day 1, 100 mmol on day 2, 150 mmol on day 3,200 mmol on day 4, 250 mmol on day 5, and 300 mmol on days 6 to 8. Body weight was recorded and blood pressure was measured after lying supine for 10 min in the morning before breakfast on entry and at the end of the low and high sodium intake periods. Urine was collected for 24 h on day -3 and from days 0 to 8 for the measurement of sodium, potassium, creatinine, free DA and free noradrenaline (NA). 3. After 4 days of sodium restriction, mean arterial pressure (mean +/- SEM) had decreased from 83.0 +/- 1.3 to 79.4 +/- 0.5 (P < 0.05) and body weight from 70.2 +/- 3.1 to 68.3 +/- 3.0 (P < 0.02). Following sodium loading, MAP and body weight did not change, but pulse rate had decreased from 64.1 +/- 2.8 to 57.4 +/- 2.6 (P < 0.02). 4. There was a 13-fold increase in sodium excretion (P < 0.02) by the last day of the high sodium intake period. There were no significant changes in urine volume and urinary excretion of potassium, creatinine and free DA throughout the high sodium intake period. In contrast, there was a 19.9-26.5% decrease in urine NA 4 and 6 days after the start of the increase in sodium intake. 5. Healthy Chinese subjects do not have a renal DA response to gradually increasing sodium intake over an 8-day period. Any tendency to hypervolaemia-related rises in blood pressure during the high sodium intake period may be partly offset by a reduction in sympathetic nervous system activity.

Effectiveness and safety of low-dose pravastatin and squalene, alone and in combination, in elderly patients with hypercholesterolemia

A double-blind, placebo-controlled study was conducted to compare the efficacy and safety of low-dose (10 mg) prevastatin and squalene (860 mg), either alone or in combination therapy, with placebo in the treatment of elderly patients with hypercholesterolemia. Ambulatory elderly patients (N = 102) were assigned in randomized fashion to receive active treatment or placebo for 20 weeks after a single-blind placebo lead-in period of 8 weeks. Total cholesterol and triglyceride levels in plasma were at least 250 mg/dL and less than 300 mg/dL, respectively. Concentrations of lipids and lipoproteins were measured, and clinical laboratory tests included liver function and creatine kinase determinations. Pravastatin 10 mg daily was more effective than squalene in reducing total cholesterol, low-density lipoprotein (LDL) cholesterol, and triglycerides and in increasing levels of high-density lipoprotein (HDL) cholesterol. Combination therapy significantly reduced total cholesterol and LDL cholesterol and increased HDL cholesterol to a greater extent than either drug alone. Adverse events and clinical laboratory abnormalities were generally mild and transient in all groups, and all but two patients finished the study. The incidence of side effects was low; myopathy did not occur. Coadministration of pravastatin and squalene combined the specific effects of the two drugs on lipoprotein concentrations. This combination may be useful and more cost-effective in elderly patients with hypercholesterolemia, who might have a higher incidence of side effects when using larger doses of pravastatin alone.

Effect of oral estradiol on Lp(a) and other lipoproteins in postmenopausal women. A randomized, double-blind, placebo-controlled, crossover study

BACKGROUND

Lp(a) lipoprotein level is an independent risk factor for premature coronary artery disease and cerebrovascular accident. Concentrations of this lipoprotein tend to increase after menopause.

OBJECTIVE

To determine whether oral estrogen was effective in lowering concentrations of Lp(a) lipoprotein in postmenopausal women.

METHODS

A double-blind, placebo-controlled, cross-over study was conducted during a 12-month period in 100 postmenopausal women who had undergone hysterectomy. They were randomized into two groups: group 1 received oral estradiol, 2 mg/d, for the first 6 months and placebo for the second, and group 2 received these treatments in the reverse order. After completion of the crossover study, the effect of prolonged administration of oral estradiol was examined by placing all patients on active treatment and repeating the lipoprotein measurements approximately 12 months later.

RESULTS

No significant differences were noted between the two groups at the commencement of the study (median concentration of Lp[a] lipoprotein, 10.78 mg/dL [range, 2.2 to 108.5 mg/dL] in group 1 and 12.74 mg/dL [range, 0.8 to 98.1 mg/dL] in group 2). Crossover analysis showed a 9.62% reduction in values of Lp(a) lipoprotein with estradiol treatment compared with placebo during 12 months of treatment (P < .001). With prolonged treatment, the median concentration of Lp(a) lipoprotein for those in group 1 decreased from 8.12 mg/dL (range, 1.05 to 57.4 mg/dL) to 5.77 mg/dL (range, 0.84 to 75.39 mg/dL) (P < .001). In group 2, the median concentration decreased from 8.19 mg/dL (range, 2.52 to 99.82 mg/dL) to 7.07 mg/dL (range, 0.70 to 48.79 mg/dL), but this difference was not significant (P = .63).

CONCLUSIONS

The results of this study confirm the beneficial effect of oral estradiol on the basic lipoprotein pattern and demonstrate that this treatment is effective in reducing concentrations of Lp(a) lipoprotein in postmenopausal women.

A comparison of the pharmacokinetics and pharmacodynamics of cilazapril between Chinese and Caucasian healthy, normotensive volunteers

METHODS

The pharmacokinetics and pharmacodynamics of the angiotensin converting enzyme (ACE) inhibitor cilazapril were studied in 12 Chinese and 13 Caucasian, healthy, normotensive volunteers on their normal diet. Cilazapril was given orally as a single 2.5 mg capsule. Plasma was sampled for assay of the active metabolite, cilazaprilat, plasma renin activity (PRA), aldosterone, angiotensin I (AI) and ACE-activity. Plasma concentrations of the active drug were measured by radioimmunoassay. Blood pressure and heart rate were measured at regular intervals.

RESULTS

The pharmacokinetic parameters of cilazaprilat were similar in the two ethnic groups. No significant difference in plasma concentrations was found at any of the time points. However, the weight-adjusted plasma clearance was significantly higher in the Chinese group, which is compatible with their lower body weight. The effects on plasma hormones were also comparable, although there was a somewhat greater rise in PRA and greater fall in aldosterone levels in Chinese than in Caucasians. The effect of cilazapril on blood pressure and heart rate was greater than was previously reported in healthy volunteers. Systolic (SBP) and diastolic (DBP) blood pressure were significantly reduced in both groups, but there was a more prolonged reduction in DBP in Caucasians. In addition, heart rate (HR) was significantly increased from baseline from 5 h onwards in Chinese subjects and significantly higher in comparison with Caucasians at most time points from 1.5 h onwards. The pharmacokinetic parameters of cilazapril were essentially the same in healthy, normotensive Chinese and Caucasians. Cilazapril reduced blood pressure acutely in both groups, with good tolerance. The inhibition of ACE in relationship to time and the plasma concentrations of cilazaprilat were similar in the two groups, although the changes in PRA and aldosterone suggest an ethnic difference in the responses of the renin-angiotensin-aldosterone system.

Cross-national comparison of family dynamics during the third trimester of pregnancy in the United States and Iceland

In a cross-national analysis of family dynamics in the United States and Iceland, we examined several factors that influence family life during the third trimester of pregnancy. Three hundred five women and 113 of their partners completed the Family Dynamics Measure (Lasky et al., 1985). Marital status and social status had differential effects on family dynamics in each country. Unmarried families in the United States reported more negative family dynamics than did married families in the United States and both married and unmarried families in Iceland. Although higher social status was associated with more positive family dynamics in both countries, the effects of low social status were more pronounced in the United States. This comparison of families in two modern Western nations points to possible effects of the presence or absence of national family policies supporting childbearing families and contributes to the development of international family science.

Urinary dopamine and noradrenaline outputs during oral salt loading in healthy Chinese subjects with a family history of hypertension

1. Increased salt sensitivity has been reported in first-degree relatives of hypertensive patients. To determine if the enhanced effect of oral salt intake on blood pressure in such individuals is related to abnormal renal dopamine (DA) or sympathetic nervous system responses, we studied the effects of two different sodium intakes (20 mmol/day followed by 220 mmol/day each given for 5 days) on mean arterial pressure (MAP) and urinary excretion of sodium, free DA and noradrenaline (NA) in seven normotensive Chinese subjects with a family history of hypertension. We compared these results with those we have reported previously for normotensive subjects without a family history of hypertension. 2. There was a seven- to ten-fold increase in sodium excretion (P < 0.02). MAP increased from 80.1 +/- 2.5 to 83.1 +/- 2.1 mmHg (P < 0.05). A 23% increase in urine DA (P < 0.02) was seen on day 1. From day 2 to day 5, the increase in urine DA (12-15%) became attenuated and reached statistical significance only on days 2 and 5. There was no significant change in urinary NA output. 3. As in healthy Chinese subjects without a family history of hypertension, those with a family history showed an early but unsustained rise in urine DA during oral sodium loading. Such an increase was rather small compared to the increase in urine sodium, suggesting that renal DA only contributes partly to the natriuretic response. Unlike those with no family history, subjects with a family history showed an increase in blood pressure after oral salt loading, possibly because of inadequate suppression of sympathetic nervous system activity.

Albuminuria, insulin resistance and dyslipidaemia in Chinese patients with non-insulin-dependent diabetes (NIDDM)

In order to examine relationships between albuminuria, insulin resistance, and dyslipidaemia in non-insulin-dependent diabetes (NIDDM), we studied 164 Chinese patients (68 men, 96 women), treated with diet or oral hypoglycaemic agents, on three occasions during a 6-week period. Antihypertensive treatment, if previously prescribed, was withdrawn for at least 2 weeks before the study period. Insulin resistance was calculated from simultaneous fasting plasma glucose and insulin concentrations using the homeostasis model assessment (HOMA) method. Based on two of three 24 h urinary collections, 87 (53%) patients had normoalbuminuria, 46 (28%) microalbuminuria, and 31 (19%) macroalbuminuria. Despite similar glycaemic control, patients with abnormal albuminuria had higher mean arterial pressure, fasting plasma total cholesterol, triglyceride and serum apo B concentrations and were more insulin resistant than normoalbuminuric patients. Albuminuria correlated with mean arterial pressure (r = 0.31, p < 0.001), triglyceride (r = 0.36, p < 0.001), total cholesterol (r = 0.28, p = 0.001), apolipoprotein B (apo B) (r = 0.25, p = 0.003), and insulin resistance (r = 0.25, p < 0.002). These close associations may contribute to the increased cardiovascular risk in Chinese NIDDM patients with abnormal albuminuria.

An examination of the effect of combined cyclical hormone replacement therapy on lipoprotein(a) and other lipoproteins

Lipoprotein(a) (Lp(a)) is an independent marker of cardiovascular disease which is relatively unresponsive to treatment with most of the commonly prescribed lipid lowering drugs. Concentrations of Lp(a) increase after the menopause, and the primary aim of this study was to determine whether combined hormone replacement therapy was effective in lowering levels of Lp(a) in postmenopausal women. An open longitudinal study was conducted among 42 women who had undergone a spontaneous menopause and were attending the outpatient clinic of the Prince of Wales Hospital, Hong Kong. All subjects were treated with 2 mg oral estradiol daily and 5 mg medroxyprogesterone acetate for 12 days each calendar month. Fasting blood samples for lipoprotein measurement were taken before the commencement of treatment and at 6 and 12 months. Lp(a) levels showed a skewed distribution with a median value before treatment of 9.45 mg/dl (range 1.47-95.62 mg/dl). After 6 months, there was a reduction to 7.70 mg/dl (1.12-72.59 mg/dl) (P < 0.01), and after 12 months the median concentration was 7.14 mg/dl (0.63-69.23 mg/dl) (P < 0.001 0-12 months). There were also significant reductions in the concentrations of apo B from 116.13 to 111.62 mg/dl and LDL-C from 3.02 to 2.74 mmol/l (P < 0.05), plus a lowering of TC of borderline significance. Apo A-I increased from 162.56 to 173.35 mg/dl (P < 0.01), but there were no significant changes in HDL-C or the HDL-C subfractions. TC, LDL-C, apo B and TG concentrations were higher and HDL-C and HDL2-C concentrations were lower when blood was sampled during combined treatment with estrogen and progesterone than when estrogen was being taken alone. Levels of Lp(a) were also lower during the estrogen only phase of treatment, but none of these differences were statistically significant. This study demonstrates that combined cyclical hormone replacement therapy is effective in reducing concentrations of Lp(a). The trend towards a more atherogenic lipid profile during the combined phase of treatment suggests that attention should be given to the timing of blood sampling in future studies of this nature.

Evenoming by Bungarus multicinctus (many-banded krait) in Hong Kong

We describe the clinical course of two cases of envenoming by the many-banded krait (Bungarus multicinctus). A man developed generalized paralysis and respiratory failure with transient hypertension. Nerve conduction studies revealed normal motor and sensory conduction velocities with reduced motor unit action potential amplitudes consistent with neuromuscular blockade. He showed a slight transient response to the banded krait (B. fasciatus) antivenom but required ventilatory support for 8 days. After the fourth day, there was some response to treatment with anticholinesterase. Another man developed diplopia, dysphagia and leg weakness but recovered spontaneously after 48 hours.

The effect of percutaneous oestrogen replacement therapy on Lp(a) and other lipoproteins

OBJECTIVES

To determine the effect of percutaneous oestrogen replacement therapy on lipoprotein (a) and other plasma lipoproteins.

METHODS

Open longitudinal prospective study conducted at the hormone replacement clinic of the Prince of Wales Hospital, New Territories, Hong Kong. Thirty women who had undergone a total abdominal hysterectomy and bilateral salpingo-oophorectomy for benign gynaecological conditions were treated with 1.5 mg of percutaneous 17 beta-oestradiol gel applied daily for a period of 12 consecutive months. Measurements of plasma lipoproteins were made before the commencement of treatment and repeated at 6- and 12-month intervals.

RESULTS

There was a significant reduction in the concentrations of Lp(a) during the first 6 months of treatment, with median values falling from 7.87 mg dL-1 to 6.16 mg dL-1 (P = 0.004, 0-6 months). During the second 6 months, the median concentration increased to 9.38 mg dL-1, (P = 0.072, 6-12 months), which did not significantly differ from the baseline level (P = 0.545, 0-12 months). Significant reductions in the concentrations of apoprotein A-I (apo A-I), apoprotein B (apo B), high density lipoprotein cholesterol (HDL-C), and HDL3-C were also present after 6 months (P = 0.043, 0.049, 0.028, 0.013, respectively), but there were no differences between the baseline values of these lipoproteins and those at the completion of the study (P = 0.948, 0.244, 0.839, 0.117 respectively). Drug compliance was maintained throughout the study, with similar mean oestradiol concentrations at 6 and 12 months.

CONCLUSIONS

The percutaneous administration of 17 beta-oestradiol has variable short term effects on plasma lipoproteins which are not maintained over a longer duration of treatment. By avoiding the 'first pass' effect on the liver, this method of delivery does not appear to produce the sustained changes in lipoproteins seen with oral treatment.

Effects of fluvastatin on lipid profile and apolipoproteins in Chinese patients with hypercholesterolemia

The effects of fluvastatin treatment on lipid profile and apolipoproteins were assessed in a group of 31 Chinese patients with hypercholesterolemia, maintained on a constant low-fat diet. Some patients had the additional cardiovascular risk factors of hypertension and non-insulin-dependent diabetes mellitus, and 6 patients had familial hypercholesterolemia. Baseline lipid levels were measured after a 4-week placebo period, and these were repeated after 4 weeks of treatment with fluvastatin 20 mg daily, and after 4 weeks of treatment with fluvastatin 40 mg daily. Total cholesterol, low density lipoprotein cholesterol, and apolipoprotein (apo) B were each reduced to the same extent with the 2 doses of fluvastatin (-20%, -26%, and -20%, respectively). Triglycerides and very low density lipoprotein cholesterol were also reduced by about 12% with the 2 doses of fluvastatin. Apo A-I was increased by 7% and high density lipoprotein cholesterol (HDL-C) was increased by 10% with the 40 mg dose. The increase in HDL-C was due to increases in both HDL2-C (18%) and HDL3-C (7%). Lipoprotein(a) levels did not show any significant change with the 2 doses of fluvastatin in this short-term study. One patient developed reversible asymptomatic elevation of liver enzymes with the higher dose of fluvastatin; otherwise the drug was well tolerated and no patients had to be withdrawn from the study.

Comparison of the pharmacokinetics and pharmacodynamics of oral doses of perindopril in normotensive Chinese and Caucasian volunteers

1. The pharmacokinetics of perindopril and perindoprilat and the hormonal and haemodynamic responses following a single oral dose were studied in 12 Chinese and 10 Caucasian healthy, normotensive volunteers on two occasions. Perindopril was given on the first occasion as a 4 mg dose and then after at least 10 days as a weight-adjusted dose of 4 mg/70 kg. Plasma was sampled for assay of perindopril, perindoprilat, plasma renin activity (PRA), aldosterone, angiotensin I (AI) and ACE activity. Urine was collected for perindopril and perindoprilat assay. A radioimmunoassay technique was used to measure the prodrug and its active metabolite. 2. The time to maximum concentration (tmax) for perindopril was shorter for the Chinese group after the 4 mg dose (median 0.5, range 0.5-1.5 h vs median 1.0, 0.5-1.5 h P < 0.05) and also tended to be shorter after the weight-adjusted dose (median 0.5, range 0.5-1.0 h vs median 1.0, range 0.5-3.0 h). Cmax and AUC tended to be higher after the 4 mg dose in the Chinese group who had a lower body weight than the Caucasians. 3. The tmax of perindoprilat tended to be shorter for both doses and there was a tendency towards a higher Cmax after the 4 mg dose in the Chinese group but there was no statistically significant difference between the two groups. 4. There were no differences in the levels of PRA, plasma AI, plasma aldosterone or the degree of ACE-inhibition for either dose in the two ethnic groups. 5. Blood pressure was measured at intervals up to 24 h post-dose in both the supine and standing positions. Perindopril reduced blood pressure acutely with respect to the pre-dose level with good tolerability in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of transcutaneous electrical nerve stimulation (TENS) on autonomic cardiovascular reflexes

Transcutaneous electrical nerve stimulation (TENS) has been shown to have an anti-ischaemic effect in patients with angina and peripheral vascular disease that appears to be additional to any analgesic action. The mechanism for this anti-ischaemic effect is not known but it is possible that TENS interferes with the autonomic responses to ischaemia. To determine if TENS has any direct action on autonomic reflexes we have assessed the effect of high frequency TENS on a variety of standard tests of autonomic cardiovascular reflexes in 10 normal subjects. Tests were done on four consecutive days at the same time and TENS therapy or placebo was randomly allocated on 2 days each. Results of the tests were assessed by one person 'blinded' to the randomization order. These showed that TENS was associated with a significant reduction in the rise of the diastolic blood pressure (21.8 +/- 2.3 v. 17.6 +/- 17 mmHg; p < 0.05) during isometric exercise, using sustained Handgrip. There was no significant effect discernible on the changes of heart rate and blood pressure during the Valsalva manoeuvre, cold face stimulus or head-up tilt. Transcutaneous electrical nerve stimulation appears, therefore, to have a mild inhibitory action on those reflexes mediated predominantly by the sympathetic nervous system and this is more apparent when the stimulation may be greater, as during isometric exercise.

Poisoning by Chinese herbal medicines in Hong Kong: a hospital-based study

The harmful effects of some Chinese herbal medicines (CHM) have become a cause for concern among the medical profession and the general public in Hong Kong. From 1989 to 1993, at least 33 patients were treated in the Prince of Wales Hospital because of severe poisoning by CHM. Of these, 20 presented with clinical features typical of aconitine poisoning following the ingestion of "chuanwu", the main root of Aconitum carmichaeli, or "caowu", the root of Aconitum kusnezoffii. Strict legislation controlling the use of chuanwu and caowu alone would have prevented many of the severe poisonings by CHM in Hong Kong.

Aconitine poisoning due to Chinese herbal medicines: a review

Both "chuanwu", the main root of Aconitum carmichaeli, and "caowu", the root of A kusnezoffii, are believed to possess anti-inflammatory, analgesic and cardiotonic effects and have been used in Chinese materia medica mainly for the treatment of musculoskeletal disorders. They contain the highly toxic C19 diterpenoid alkaloids of aconitine, mesaconitine and hypaconitine. After ingestion, patients may present with signs and symptoms that are typical of aconitine poisoning. Death may occur from ventricular arrhythmias, which are most likely to occur within the first 24 h. Management of aconitine poisoning is essentially supportive. There are no adequate studies in humans to indicate the most effective treatment of the ventricular arrhythmias. All clinicians should be alerted to the potential toxicity of "chuanwu" and "caowu".

Urinary dopamine and noradrenaline outputs during large acute changes in oral salt intake in healthy Chinese subjects

1. In order to investigate the role of renal dopamine and sympathetic activity in the natriuretic response to oral sodium loading in Chinese subjects, we studied the effects of two different sodium intakes (20 followed by 220 mmol day-1 each given for 5 days) on mean arterial pressure (MAP) and the urinary excretion of sodium, dopamine (DA) and noradrenaline (NA) in eight healthy subjects. 2. MAP did not change. There was an eight- to ninefold increase in sodium excretion (P < 0.01). An 8-17% increase in urinary DA (P < 0.05) over the first 3 days, and a 22% decrease in urine NA (P < 0.05) on the last day of the high sodium intake were seen. 3. The relatively small increase in urinary DA, despite an eleven-fold increase in sodium intake from a state of marked sodium deprivation, may suggest that, in healthy Chinese subjects, the renal DA mechanism only contributes partly to the acute natriuretic response. Furthermore, the renal DA response appeared to be attenuated during the period of high sodium intake. 4. There is no evidence from the present study that a reduction in sympathetic activity plays an important role in the acute natriuretic response to sodium loading in this group of subjects.

The effects of enalapril and nifedipine on carbohydrate and lipid metabolism in NIDDM

OBJECTIVE

To compare the effects of nifedipine and enalapril on carbohydrate and lipoprotein metabolism in Chinese non-insulin-dependent diabetes mellitus (NIDDM) patients with hypertension.

RESEARCH DESIGN AND METHODS

A 12-week, double-blind, randomized study of plasma lipid levels and glycemic control in patients treated with nifedipine (n = 52) or enalapril (n = 50) was conducted. None of the patients were treated with insulin. Diet and dosages of oral hypoglycemic agents remained unchanged during the 12-week treatment period.

RESULTS

Mean arterial pressure was reduced more by nifedipine than by enalapril (23.1 vs. 11.1 mmHg, P < 0.001). Similar reductions in body mass index and plasma triglycerides and increases in apolipoprotein A-I were seen with both treatments, but HbA1 was reduced more during treatment with enalapril than with nifedipine (0.49 vs. 0.20%, P = 0.035) and serum apolipoprotein B (apoB) also declined more with enalapril than with nifedipine (8.2 vs. 2.3 mg/dl, P = 0.009).

CONCLUSIONS

Twelve weeks of treatment with enalapril in hypertensive NIDDM patients was associated with greater improvement in glycemic control and greater reduction in serum apoB concentration, although the reduction in blood pressure was less than with nifedipine. These changes in cardiovascular risk profile warrant investigation for a longer term.