J. A. J. H. Critchley

Chinese herbal medicines revisited: a Hong Kong perspective

Chinese herbal medicines (CHM) and Chinese proprietary medicines (CPM) are widely used by people of Chinese origin throughout the world. Although the use of these medicinal materials rarely causes significant toxic effects, cases of severe and even fatal poisoning have occurred after medication with herbs containing aconitine, podophyllin, and anticholinergic substances. Furthermore, CHM and CPM are often adulterated with substituted herbs, heavy metals, and western medicines; such contamination can have important clinical consequences. In Hong Kong, surveillance and legislation are required to control the use of some of these herbal preparations. In other countries, medical practitioners should also be aware of the possibility that these herbal-medicine-related remedies may cause significant clinical problems in their Chinese patients.

Molecular genetics of diabetes mellitus in Chinese subjects: identification of mutations in glucokinase and hepatocyte nuclear factor‐1α genes in patients with early‐onset Type 2 diabetes mellitus/MODY

Aims To examine the prevalence of identified MODY‐related genes in Chinese subjects with early onset Type 2 diabetes mellitus and a positive family history of diabetes and to look for possible associations between the gene mutations and the development of diabetes.

Smoking and diabetes in Chinese men

Smoking is a major cardiovascular risk factor and cause of death. Diabetes mellitus is also associated with an increased mortality and morbidity. Evidence concerning whether smoking increases the incidence of diabetes remains conflicting. Glycaemic status and smoking habits were analysed in 3718 Chinese subjects in order to assess the possible association between smoking and risk of diabetes in the Chinese population. The World Health Organisation 1998 criteria were used for the diagnosis of glucose intolerance. Smoking was defined as current cigarette smoking or ex-smoking without regard to daily consumption. The smoking habits of the studied subjects were correlated with glycaemic status. There were 3003 (80.8%) women and 715 (19.2%) men. The mean age (SD) was 38.4 (12.8) years (median 35.0, range 12–88 years). Of the 3718 subjects, 786 (21.1%) had diabetes, 708 (19.1%) had impaired glucose tolerance, and 2224 (59.8%) had normal results. Of the 3003 women, only 87 (2.9%) were smokers. The female smokers were younger, heavier, and had higher alcohol consumption than non-smokers. The prevalence of diabetes was similar between female smokers and non-smokers after adjustment for age, body mass index, family history of diabetes, and alcohol. Of the 715 men, 175 (24.5%) were smokers. The male smokers were younger, had lower blood pressure, and higher alcohol consumption. After adjustment for age, body mass index, family history of diabetes and alcohol, the male smokers had lower blood pressure, higher one hour plasma glucose, and more diabetes. Using logistic regression analysis (stepwise forward) with age, body mass index, alcohol, smoking, and family history of diabetes as independent variables to predict the risk of having diabetes, age and body mass index are independently associated with diabetes in both men and women. In addition, smoking is independently associated with the risk of diabetes in men, the odds ratio (95% confidence interval, CI) being 1.705 (1.106 to 2.630). Family history of diabetes is independently associated with the risk of diabetes in women, and the odds ratio (95% CI) is 1.643 (1.314, to 2.053). In conclusion, it was found that smoking is independently associated with diabetes after adjustment for age, body mass index, alcohol, and family history of diabetes in Hong Kong Chinese men, the odds ratio being 1.7. The prevalence of smoking in Hong Kong Chinese women is low and its association with diabetes is inconclusive.

Differences in the single-oral-dose pharmacokinetics and urinary excretion of paracetamol and its conjugates between Hong Kong Chinese and Caucasian subjects.

Background and Objectives:u2002 The present study was conducted to determine if ethnic differences exist for single oral dose pharmacokinetics of paracetamol and its conjugates between Hong Kong Chinese and Caucasian subjects.

The islet amyloid polypeptide (amylin) gene S20G mutation in Chinese subjects: Evidence for associations with type 2 diabetes and cholesterol levels

BACKGROUND and OBJECTIVES There has been evidence that the S20G mutation in the islet amyloid polypeptide (amylin) gene may be associated with type 2 diabetes. In the present study, we investigated the distribution of the mutation in Hong Kong Chinese, and examined whether there was evidence for associations between the mutation and type 2 diabetes and/or metabolic profiles.

Acute effects of the potent lacrimator o-chlorobenzylidene malononitrile (CS) tear gas:

1 The use of tear gas to control civil unrest is accepted practice by government authorities worldwide. It is rarely used in Hong Kong but during a recent riot at a Vietnamese detention centre large quantities were used and this was cause for some concern. 2 All patients presenting to the British Red Cross Clinic after the incident were seen by one of the authors. To establish if exposure to tear gas had serious effects on the health of the detainees, the case records of the 184 patients with symptoms consistent with CS exposure were reviewed 2 months later. 3 The most common complaints were burns (52%), cough (38%), headache (29%), shortness of breath (21%), chest pain (19%), sore throat (15%) and fever (13%). However, the only common findings on examination by a physician were burns (52%) and an inflamed throat (27%). All burns could be categorised as minor according to the American Burns Association classi fication and all were consistent with CS gas exposure. 4 Some patients complained of other symptoms that had not been previously reported in the literature, such as haemoptysis (8%) and haematemesis (4%), but these were only confirmed in one patient. 5 The majority of patients had recovered within 2 weeks of exposure although one asthmatic patient com plained of shortness of breath lasting for 33 days and a sore throat lasting for 38 days after the incident. She had abnormally low peak expiratory flow readings, but had a clinical history of asthma. 6 No serious sequelae were encountered, but the incidence of burns in these patients was higher than would be expected from a review of the literature. However, very little data on the effects of tear gas in a riot situation has been published. There have been reports of high concentrations of CS gas causing reactive airways dysfunction but this was not seen in our group of patients.

RENIN-ANGIOTENSIN-ALDOSTERONE SYSTEM GENE POLYMORPHISMS AND HYPERTENSION IN HONG KONG CHINESE

In Chinese populations, hypertension is common and is a major risk factor for cerebrovascular and coronary heart disease. The renin-angiotensin-aldosterone system (RAAS) helps maintain blood pressure and salt homeostasis and appears important in the pathogenesis of hypertension and some forms of vascular disease. We investigated three RAAS gene polymorphisms, the angiotensin-converting enzyme (ACE) insertion/deletion, angiotensinogen (AGT) M235T and angiotensin II type 1 receptor A1166C polymorphisms in 232 hypertensive and 178 normotensive Chinese subjects. The hypertensives were generally more obese and dyslipidaemic. No significant differences in genotype or allele frequencies for any of the polymorphisms were identified between the groups, nor was there any interactive contribution to blood pressure by the ACE and AGT polymorphisms. However, there were large differences in genotype and allele frequencies between the healthy Chinese and published data for equivalent Caucasian populations. These findings suggest these polymorphisms are unlikely to be involved in the pathogenesis of hypertension in Chinese.

Mitochondrial DNA A3243G mutation in patients with early‐ or late‐onset type 2 diabetes mellitus in Hong Kong Chinese

The mitochondrial DNA A to G mutation at nucleotide 3243 (mt3243) is associated with a subtype of diabetes characterized by maternal transmission and deafness. We have previously reported a 2.7% prevalence of this mutation in a cohort of young patients with either type 1 or type 2 diabetes. In this study, we aimed to confirm this finding by examining for the prevalence of this mutation in a large‐scale study.

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 20u2005mgu2005kg−1, and the excretion of 6ß-hydroxycortisol as a ratio to urinary free cortisol(6ßOHF/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 6ßOHF/F was signi ficantly 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.

Drug utilization in a hospital general medical outpatient clinic with particular reference to antihypertensive and antidiabetic drugs

Objectives: To examine the prescribing patterns, particularly antihypertensive and antidiabetic drugs, in a hospital outpatient clinic and to evaluate the expenditure incurred. Methods: Prescriptions from a general medical outpatient clinic in a teaching hospital were collected for 4 weeks. Drug expenditures were calculated. Results: A total of 622 prescriptions containing 1903 items were collected. Antihypertensive and antidiabetic drugs accounted for 25·9 and 9·1% usage, respectively. Calcium channel blocking agents, angiotensin converting enzyme inhibitors and β‐blocking agents were the most popular antihypertensive drugs used. Sulphonylureas were the most frequently prescribed antidiabetic agents. Amlodipine, doxazosin and sotalol accounted for 4·5% of all prescription items but 27·8% of the total drug expenditure. Conclusion: The use of antihypertensive and antidiabetic drugs accounted for most of the drug usage in this study. Use of newer and more expensive agents has further increased drug expenditure. Monitoring drug usage and their correlations with clinical outcomes are warranted.