Type 1 diabetes and arterial dysfunction in asymptomatic Chinese adults.
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Adult↗
Biomedical subjects
W B Chan
Publications and source records attributed to W B Chan.
Triploid pregnancy after ICSI of frozen testicular spermatozoa into cryopreserved human oocytes: case report.
Although freezing oocytes is ethically more acceptable than cryopreservation of embryos, variable oocyte survival, fertilization rate and possible risk of increased ploidy after cryopreservation have precluded the widespread clinical application of oocyte cryopreservation in assisted reproduction techniques. We report a triploid pregnancy from intracytoplasmic sperm injection of recombinant FSH-stimulated frozen/thawed testicular spermatozoa into cryopreserved oocytes in a hormone replacement cycle. To our knowledge, this is the first report of a pregnancy where both gametes have been frozen. It illustrates the need for further research when applying new techniques in assisted reproduction.
Abortion, Missed↗
Glycaemic control in type 2 diabetes: the impact of body weight, beta-cell function and patient education.
We examined the determinants of glycaemic control in a consecutive cohort of 562 newly-referred Chinese type 2 diabetic patients (57% women) during a 12-month period. All patients underwent a structured assessment with documentation of clinical and biochemical characteristics. Pancreatic beta-cell function was assessed by fasting plasma C-peptide concentration. Insulin deficiency was defined as fasting plasma C-peptide <0.2 pmol/ml. Insulin resistance (IR) was calculated using the homeostasis model assessment (HOMA) based on a product of fasting plasma glucose and insulin concentrations. Treatment was considered appropriate when insulin-deficient patients were treated with insulin and non-insulin-deficient patients were treated with oral agents or diet. Mean (+/-SD) age was 54.3+/-13.8 years (range 17-87 years) and disease duration was 5.0+/-5.9 years. At the time of referral, 70.5% (n=396) were on drug therapy (9% on insulin and 62.8% on oral agents), 20.6% (n=116) were on diet and 9% (n=50) had not received any form of treatment. The mean HbA(lc) was 8.4+/-2.3%. The geometric mean (x// antilog SD) of IR was 4.62x//2.51 (range 0. 63-162.7) and correlated only with waist : hip ratio (WHR, p=0.008). The geometric mean of plasma C peptide was 0.47x//2.89 nmol/l and correlated with BMI (p<0.001). Glycated haemoglobin was correlated positively with age (p=0.013), disease duration (p<0.001), IR (p<0. 001) and negatively with BMI (p<0.001). Glycated haemoglobin was lower in patients who had seen a dietitian (7.9% vs. 8.7%, p<0.001) or diabetes nurse (7.8% vs. 8.7%, p<0.001) or who performed self blood glucose monitoring (7.9% vs. 8.6%, p=0.001) and higher among smokers (8.9% vs. 8.2%, p=0.003). Compared to insulin-deficient patients (n=118), non-insulin-deficient patients (n=413) had features resembling that of the Metabolic Syndrome with increased WHR (p=0.005), blood pressure (p<0.001), BMI (p=0.001) and were older (p=0.04). Amongst the insulin-deficient patients, 27% were treated with oral agents or diet. Patients receiving appropriate therapy (n=362) had a lower HbA(lc) than those treated inappropriately (n=173) (8.2% vs. 8.7%, p=0.02). On multivariate analysis, short disease duration (p<0.001), low IR (p<0.001), high BMI (p=0.001), diabetes education (p<0.001), lack of smoking (p=0. 014) and choice of appropriate treatment (p=0.009) were the independent determinants of good glycaemic control.
Adolescent↗
Spontaneous necrosis of parathyroid adenoma: biochemical and imaging follow-up for two years.
We report a patient with a biochemically and radiologically confirmed parathyroid adenoma, which underwent spontaneous resolution by necrosis. The patient was followed-up over the subsequent two years during which time the tumour and hypercalcaemia recurred. Sequential radiological and biochemical changes at the time of diagnosis, spontaneous necrosis and recurrence are documented fully.
Adenoma↗
Diabetes in Hong Kong Chinese: evidence for familial clustering and parental effects.
OBJECTIVE: To investigate transmission patterns of diabetes and their relationships with clinical characteristics in Hong Kong Chinese patients with late-onset (age > or =35 years) type 2 diabetes. RESEARCH DESIGN AND METHODS: This study involved 2,310 patients consecutively selected from a hospital clinic-based diabetes registry. These patients all reported the diabetes status of their parents as well as siblings. RESULTS: Approximately 36% of the 2,310 patients reported at least 1 affected parent or sibling (25 and 21% reported at least 1 diabetic parent and sibling, respectively). These patients, irrespective of their sex, were more likely to have a diabetic mother than a diabetic father (17 vs. 13% of the male patients and 18 vs. 9% of the female patients, P<0.01). The male patients were more likely than the female patients to have a diabetic father (13 vs. 9%, P<0.01). The female patients with a diabetic mother were found to have higher levels of plasma total cholesterol compared with the female patients with a diabetic father in multiple comparisons with adjustment for significance (5.56+/-1.30 vs. 5.09+/-0.95 mmol/l, P<0.05). In 2-group comparisons, there was also evidence that the male patients with a diabetic father had higher BMI values than the male patients with a diabetic mother (25.9+/-3.5 vs. 25.0+/-3.5 kg/m2, P<0.05). CONCLUSIONS: We found familial clustering of diabetes in the Hong Kong Chinese population as well as a significant maternal influence and a male sex-specific paternal effect. We suggest that both maternal and paternal factors may be implicated in the development of type 2 diabetes in the Chinese population.
Adult↗
Rapid prenatal diagnosis of chromosome abnormalities.
The aim of the present work was to examine the efficacy of using FISH for the rapid prenatal diagnosis of common chromosome aneuploidies. A total of 100 analyses over a six month period were included in the study. Diagnosis was possible in all cases. A mosaic for trisomy 21 proved, by comparison with an extensive analysis of long term cultures, to be an apparent false positive. Otherwise the technique was reliable, accurate and relatively straightforward to perform. Results could be available within 24 hrs. In most cases an additional long term full analysis was also done, so as to exclude rarer aneuploidies and structural rearrangements. This methodology is seen as a useful addition to the prenatal diagnostic repertoire.
Chromosome Aberrations↗
Gastrointestinal symptoms in Chinese patients with Type 2 diabetes mellitus.
AIMS: To examine and compare gastrointestinal (GI) symptoms in Hong Kong Chinese Type 2 diabetic outpatients and non-diabetic control subjects. METHODS: A total of 149 Chinese Type 2 diabetic patients (66 men and 83 women, age (mean +/- SD) 46.8+/-11.1 years) newly referred to the diabetes clinic of the Prince of Wales Hospital, Hong Kong were examined. Sixty-five age and sex-matched non-diabetic subjects were recruited from the community as controls (22 men and 43 women, age (mean +/- SD) 46.5+/-6.6 years, P = 0.820). All patients were interviewed regarding GI symptoms over the past year, using a questionnaire that covered 14 items. A scoring system from 0 to 4 was used to grade severity. RESULTS: Diabetic patients had higher blood pressure, fasting plasma glucose and glycated haemoglobin and were more often smokers than control subjects. Of the 149 diabetic subjects, 105 (70.5+/-45.8%) had GI symptoms while only 20 (30.8%) of the 65 control subjects had GI symptoms (P<0.001). The respective percentages of upper and lower GI symptoms in diabetic and normal subjects were 44.3% vs. 24.6% (P = 0.006) and 54.4% vs. 13.9% (P<0.001). The three commonest GI symptoms in diabetic patients were diarrhoea (34.9%), constipation (27.5%) and epigastric fullness (16.8%). After adjustment for age, sex, duration of diagnosed diabetes and smoking, patients with or without metformin had similar percentages or scores for GI symptoms. On multivariate analysis using age, body mass index, fasting plasma glucose, glycated haemoglobin, duration of diagnosed diabetes and presence of peripheral neuropathy as independent variables, duration of diabetes was the only independent parameter associated with total score for GI symptoms (beta = 0.116, P = 0.003), for upper GI symptoms (beta = 0.073, P = 0.005) and for lower GI symptom (beta = 0.043, P = 0.020). CONCLUSIONS: Up to 70% of the Chinese Type 2 diabetic outpatients have GI symptoms, which is a much higher rate than in non-diabetic control subjects. Duration of diabetes is the most important factor associated with the presence of such GI symptoms.
Adult↗
Prevalence and distribution of Helicobacter pylori in gastroesophageal reflux disease: a study from the East.
OBJECTIVES: The relationship between Helicobacter pylori infection and gastroesophageal reflux (H. pylori) disease (GERD) is controversial. In Asian populations, the prevalence of H. pylori infection is high and GERD is relatively uncommon. The aim of this study was 1) to test the hypothesis that H. pylori protects the esophagus against GERD, and 2) to study the pattern of H. pylori colonization and gastritis in GERD. METHODS: We conducted a prospective case-control study in which patients with GERD and asymptomatic controls were compared for the prevalence of H. pylori infection. Diagnosis of GERD was based on symptoms of heartburn that improved with acid-suppressive therapy and/or endoscopic evidence of erosive esophagitis. H. pylori status was determined by serology and, when endoscopy was indicated, was confirmed by rapid urease test and histology. Gastric biopsies were examined under hematoxylin and eosin and Giemsa stains. Density of H. pylori colonization and activity of gastritis at different parts of stomach were graded and compared according to Updated Sydney system. RESULTS: A total of 106 patients with GERD and 120 age- and sex-matched, asymptomatic controls were enrolled. The prevalence of H. pylori infection was significantly lower in GERD patients (31%) compared with controls (61%, p < 0.001, odds ratio 0.229, 95% confidence interval 0.13-0.41). H. pylori-infected GERD patients showed significantly more severe gastritis in the antrum than in other parts of stomach (mean inflammatory scores: antrum; 3.3 +/- 1.63*, body; 1.85 +/- 1.31; fundus; 1.65 +/- 0.58; cardia, 1.65 +/- 1.39; *p < 0.005). H. pylori colonization was found less commonly and at lower density at the cardia compared with other parts of the stomach. CONCLUSIONS: H. pylori infection protects against the development of GERD, and carditis is unlikely to play an important role.
Adult↗
Gynaecomastia as a presenting feature of thyrotoxicosis.
The association between gynaecomastia and thyrotoxicosis is well recognised. However, the reported frequency of the association is variable, partly depending upon the defining criteria used. Here we report two patients with thyrotoxicosis in whom gynaecomastia was the presenting feature. Both patients had other contributing factors, which are assumed to have predisposed to gynaecomastia. In both patients, the gynaecomastia resolved with successful treatment of the thyrotoxicosis. When gynaecomastia is a presenting, or prominent feature of thyrotoxicosis, the possibility of additional underlying pathology should be considered.
Adult↗
Glycated haemoglobin and cardiovascular risk factors in Chinese subjects with normal glucose tolerance.
Increased plasma glucose concentration is a predictive factor for mortality in both diabetic and non-diabetic subjects. Although glycated haemoglobin (HbA1c) is a useful index of mean blood glucose concentrations over the preceding 1 to 3 months, there are few data regarding its relationship to cardiovascular risk. We have examined the relationship between HbA1c and cardiovascular risk factors in 1280 subjects with normal glucose tolerance. Based on HbA1c tertiles (tertile 1: n = 427, 262 men and 165 women, HbA1c level: 2.9-4.7% in men and 3.2-4.2% in women; tertile 2: n = 426, 261 men and 165 women, HbA1c level: 4.7-5.1% in men and 4.2-4.6% in women; tertile 3: n = 427, 262 men and 165 women, HbA1c level: 5.1-6.7% in men and 4.6-6.9% in women), increasing HbA1c was associated with increasing age, blood pressure, waist-hip ratio, fasting and 2-h plasma glucose, 2-h insulin, cholesterol, low-density lipoprotein cholesterol, apolipoprotein B and urate concentrations. When age and sex were included as covariates, increasing HbA1c remained associated with increasing fasting and 2-h plasma glucose, 2-h insulin, total cholesterol, and low-density lipoprotein cholesterol concentrations. These findings emphasize the importance of hyperglycaemia, as reflected by HbA1c, as a continuum in the evaluation of cardiovascular risk. Furthermore, these findings support the hypothesis that cardiovascular disease risk commences with rising glucose concentrations before 'conventionally-defined' glucose intolerance occurs.
Adult↗
Rectal carcinoma during pregnancy.
Rectal carcinoma presenting during pregnancy is rare with a reported incidence of 0.002%. Management of such an emotionally charged condition can be difficult, especially when the twin goals of curing the disease and preserving the pregnancy are divergent. Four cases of rectal carcinoma presenting during pregnancy are reported. In the first or second trimester of pregnancy, it is possible to resect the tumour with preservation of pregnancy, and in the third trimester, it is best to bring the pregnancy to term before removing the tumour. Unfortunately, the prognosis for such rectal cancer is poor.
Abortion, Spontaneous↗
Racial differences in fetal morphometry in Singapore.
A systematic collection of fetal morphometric measurements was started seven years ago in 1987 with the prospective entry of data into personal computer-based stations in the Department of Obstetrics and Gynaecology, Singapore General Hospital. A cross-sectional study was done, comparing 2392 Chinese fetuses with 2117 Malay fetuses and 459 Indian fetuses from 18 to 40 weeks. The mean values of the head circumference (HC), abdominal circumference (AC) and femur length (FL) of the 3 ethnic groups were analysed. There were no statistical significant differences in the head circumference and abdominal circumference of Chinese, Malay and Indian fetuses in Singapore. The Chinese and Malay fetal femur length appeared similar but were apparently shorter than the Indian femur length. Nomograms of head circumference, abdominal circumference and femur length were constructed for application to fetuses of all 3 ethnic groups.
Abdomen↗
A comparison of fetal biparietal diameter measurements between local Chinese and Caucasian populations.
Since the advent of ultrasound, various workers have published nomograms of the fetal biparietal diameters (BPD). In the Singapore General Hospital, the nomogram established by Campbell and Newman was adopted initially for our multi-racial society. Data from the cross-sectional study of the 1442 BPD measurements of the Chinese fetuses between 17 to 40 weeks showed that the mean BPD values of the Chinese fetuses are lower than the Caucasians. The 2 standard errors of the BPD of the Chinese fetuses does not lie within the 2 standard errors of the BPD of the Caucasian fetuses. The reasons for the difference remain speculative. The presence of the statistical difference between the two means and the 2 standard errors establishes the need for constructing nomograms for our own local reference.
Asian People↗
The sagittal appliance.
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Equipment Design↗
Triglyceride predicts cardiovascular mortality and its relationship with glycaemia and obesity in Chinese type 2 diabetic patients.
BACKGROUND: To examine the lipid profile in Chinese type 2 diabetic patients and their relationship with anthropometric parameters, glycaemic control and cardiovascular mortality. METHODS: A consecutive cohort of 562 newly referred patients with type 2 diabetes to a hospital-based diabetes centre were examined in 1996. Subjects treated with lipid lowering drugs at the time of referral were excluded. A total of 517 subjects were followed up over a mean (+/-SD) period of 4.6 +/- 0.9 years. Glycated haemoglobin (HbA1c), fasting insulin and lipid profile and anthropometric parameters were documented at the time of recruitment. Cardiovascular mortality, mainly due to coronary heart disease and stroke, was ascertained using death registry and review of hospital case notes in 2001. RESULT: Of the 517 subjects (mean age of 54.0 +/- 14.0 years), 42.6% were men. In this cohort, 63.3% of subjects were either overweight (BMI > or = 23 kg/m2) or obese (BMI > or = 25 kg/m2) using Asian criteria. The mean (+/-SD) total cholesterol (TC), LDL-Cholesterol (LDL-C), HDL-Cholesterol (HDL-C) and geometric mean (x// antilog SD) of triglycerides (TG) were 5.6 +/- 1.3 mmol/L, 3.6 +/- 1.1 mmol/L, 1.3 +/- 0.3 mmol/L and 1.46x//1.90 mmol/L respectively. TC and LDL-C correlated positively with HbA1c, HDL-C negatively with BMI and WC (waist circumference), while TG positively with HbA1c, BMI, WC and HOMA (insulin resistance estimated using the homeostasis model assessment). During the 4.6 years follow-up period, there were 61 deaths giving a total mortality rate of 11.4%, of which 15 (25%) were because of cardiovascular events. Apart from age and disease duration, logarithm of TG was significantly associated with increased risk of cardiovascular mortality (p = 0.049, relative risk = 2.97, 95% CI 1.00-8.77). CONCLUSIONS: Chinese type 2 diabetic patients had a lower prevalence of obesity, lower TG and higher HDL-C than Caucasian patients. Despite the low incidence of cardiovascular death, TG, which was closely associated with obesity indexes, was significantly associated with cardiovascular death in these patients.
Blood Glucose↗
Helicobacter pylori infection in Chinese subjects with type 2 diabetes.
The relationship between diabetes and Helicobacter pylori (HP) infection is controversial. In this study, we examined the possible relationship between HP infection and type 2 diabetes in Chinese subjects. Sixty-three Chinese type 2 diabetic patients (mean age +/- SD: 49.9 +/- 12.0 years; range: 17-76 years) were recruited irrespective of the duration of diabetes or type of therapy. Twenty-nine (46%) of them had upper gastrointestinal symptoms and the other 34 (54%) did not. Another 55 age- and sex-matched non-diabetic subjects (mean age +/- SD: 45.6 +/- 15.6 years, p=0.098; range 18-79 years) with dyspepsia indicated for upper endoscopy were recruited as a comparison group. Upper endoscopy was performed with antral mucosal biopsy specimens taken for rapid urease test (CLO test). HP infection was considered to be present if the rapid urease test was positive. The rates of HP infection of the diabetic and non-diabetic individuals were 50.8% and 56.4% respectively (p: NS). The rate of HP infection was similar between the 2 groups of diabetic patients with or without gastrointestinal symptoms (42.9% vs. 56.3%, p: NS). Using logistic regression analysis (forward stepwise) with age, sex, glycaemic control, duration of diabetes and upper gastrointestinal symptoms as independent variables to predict the risk of HP infection in diabetic patients, none of the parameters enter into the model. In conclusion, the rate of HP infection in Hong Kong Chinese subjects with type 2 diabetes is around 50%, which is similar to control subjects. No association was found between HP infection, glycaemic status, and duration of diabetes and upper gastrointestinal symptoms in these diabetic subjects.
Adolescent↗