Biomedical subjects

J S Cheah

Publications and source records attributed to J S Cheah.

At least 19 recordsLinked to original sources

PubMed1992

Medical treatment of Cushing's syndrome with aminoglutethimide and ketoconazole.

We report a 54-year-old Chinese man with Cushing's syndrome from bilateral adrenal adenomata in whom surgery was contraindicated because of his intercurrent medical conditions. Instead, he was successfully treated with aminoglutethimide 0.75 gm/day (which reduced his 24-hour urinary free cortisol from 628 nmol/day to 177 nmol/day in 4 weeks), followed by ketoconazole 0.6 gm/day which continued to suppress the urinary free cortisol level. We conclude that aminoglutethimide or ketoconazole offers a viable non-surgical alternative to the treatment of Cushing's syndrome.

Adenoma↗

PubMed1991

Hyperinsulinaemia in thyrotoxic hypokalaemic periodic paralysis.

To test the hypothesis that there is an abnormal serum insulin response to a carbohydrate load in thyrotoxic hypokalaemic periodic paralysis (THPP), 18 men with THPP and 15 with uncomplicated thyrotoxicosis were studied during an oral glucose tolerance test. The THPP group had significantly higher fasting insulin concentrations (27.6 [3.6] vs 13.4 [1.8] mU/l; p less than 0.005) and a higher overall insulin response to oral glucose (p less than 0.001 by ANOVA) than the thyrotoxicosis group. There were no significant differences in fasting or stimulated glucose. Hyperinsulinaemia may be an important factor in the precipitation of acute paralysis in THPP.

Acute Disease↗

PubMed1990

Oestrogen and progesterone receptors in men with bilateral or unilateral pubertal macromastia.

Abnormalities at the tissue receptor level may be important in the pathophysiology of pubertal macromastia, which may be unilateral or bilateral. We studied breast tissue removed from seven boys of age 16-17 years, five with bilateral and two with unilateral gynaecomastia. We confirmed that their physical features, karyotype, and plasma concentrations of testosterone, oestradiol, LH, FSH, and prolactin were all normal for adolescent males. Oestrogen and progesterone receptors were measured with a steroid binding (dextran coated charcoal) assay which was used for breast cancer receptor studies. Oestrogen receptors were not detectable in any of the 12 breasts studied. Progesterone receptors were detectable at a low level in two patients with bilateral gynaecomastia, one breast from each patient. We conclude that although the development of bilateral or unilateral male macromastia in puberty may yet be mediated by a local tissue receptor abnormality, this disorder is probably not mediated by an abnormal increase in oestrogen receptor number.

Adolescent↗

PubMed1990

Cardiovascular diseases in Chinese, Malays, and Indians in Singapore. II. Differences in risk factor levels.

STUDY OBJECTIVE: The aim of the study was to examine cardiovascular risk factors to see how these might explain differences in cardiovascular disease mortality among Chinese, Malays, and Indians in the Republic of Singapore. DESIGN: The study was a population based cross sectional survey. Stratified systematic sampling of census districts, reticulated units, and houses was used. The proportions of Malay and Indian households were increased to improve statistical efficiency, since about 75% of the population is Chinese. SETTING: Subjects were recruited from all parts of the Republic of Singapore. SUBJECTS: 2143 subjects aged 18 to 69 years were recruited (representing 60.3% of persons approached). There were no differences in response rate between the sexes and ethnic groups. MEASUREMENTS AND MAIN RESULTS: Data on cardiovascular risk factors were collected by questionnaire. Measurements were made of blood pressure, serum cholesterol, low and high density lipoprotein cholesterol, fasting triglycerides and plasma glucose. In males the age adjusted cigarette smoking rate was higher in Malays (53.3%) than in Chinese (37.4%) or Indians (44.5%). In both sexes, Malays had higher age adjusted mean systolic blood pressure: males 124.6 mm Hg v 121.2 mm Hg (Chinese) and 121.2 mm Hg (Indians); females 122.8 mm Hg v 117.3 mm Hg (Chinese) and 118.4 mm Hg (Indians). Serum cholesterol, low density lipoprotein cholesterol and triglyceride showed no ethnic differences. Mean high density lipoprotein cholesterol in males (age adjusted) was lower in Indians (0.69 mmol/litre) than in Chinese (0.87 mmol/litre) and Malays (0.82 mmol/litre); in females the mean value of 0.95 mmol/litre in Indians was lower than in Chinese (1.05 mmol/litre) and Malays (1.03 mmol/litre). Rank prevalence of diabetes for males was Indians (highest), Malays and then Chinese; for females it was Malays, Indians, Chinese. CONCLUSIONS: The higher mortality from ischaemic heart disease found in Indians in Singapore cannot be explained by the major risk factors of cigarette smoking, blood pressure and serum cholesterol; lower high density lipoprotein cholesterol and higher rates of diabetes may be part of the explanation. The higher systolic blood pressures in Malays may explain their higher hypertensive disease mortality.

Adolescent↗

PubMed1990

IgG-class insulin autoantibodies in autoimmune thyroid disease.

We studied the incidence of insulin autoantibodies (IAA) in 97 patients with autoimmune thyroid disease with an enzyme-linked immunosorbent assay. The sera were also tested for islet cell antibodies (ICA) and thyrotropin receptor antibodies (TRAb). IAA as assessed by a standard deviation score were present in 7 patients (7.2%). None of the patients were seropositive for ICA. Data from this random sampling and a retrospective study of 12 patients on antithyroid drug treatment indicated that the presence of IAA was not associated with TRAb.

Adolescent↗

PubMed1990

Cushing's disease in pregnancy.

Cushing's disease in pregnancy is rare and is associated with an increased incidence of maternal morbidity, premature delivery, spontaneous abortions and stillbirths. We report a successful term pregnancy in a patient with Cushing's disease due to a pituitary microadenoma. The literature is reviewed.

Adenoma↗

PubMed1990

Treatment of adrenal cortical carcinoma with mitotane: outcome and complications.

Adrenal cortical carcinoma is a rare tumour with a poor prognosis. We report a patient with metastatic adrenal cortical carcinoma who responded dramatically to Mitotane (o,p'-DDD). Unlike previous reports of metastatic adrenal cortical carcinoma in which complete remission was obtained with high dose Mitotane treatment, the dose of Mitotane used in this patient was low. However, she developed unusual side-effects such as hyperpigmentation, low plasma cortisol and high adrenocorticotropic (ACTH) levels. The side effects closely resemble those in Nelson's syndrome and were reversed by cortisone replacement. The mechanism of actions of Mitotane is discussed with emphasis on its effect on corticosteroid metabolism.

Adrenal Cortex Neoplasms↗

PubMed1990

A study of non-toxic goitre.

A population study showed a prevalence of 2.8% for nontoxic goitres. The clinical significance of non-toxic goitres were not previously defined. This study examined 64 patients with non-toxic goitres which were classified clinically as diffuse (gp1), lobular (gp2) and nodular (gp3). They were studied in terms of thyroid antibodies, radioisotope scanning, ultrasonography and fine-needle aspiration cytology. The goitres were mainly nodular (69%), the rest were diffuse and lobular in equal numbers. Seventy percent of the nodular goitres had 1 nodule. One case of diffuse goitre and half the lobular goitres had multinodularity demonstrated on imaging. Antithyroid antibodies were detected in 20% of gp2, 7% of gp3 and none in gp1. Malignancy was found in 2% of gp2, 11% of gp3 and nil in gp1. A management strategy for non-toxic goitre was discussed.

Adolescent↗

PubMed1990

Humoral immune abnormalities in diabetes mellitus.

We previously showed that for Singapore diabetics, a low prevalence of islet cell antibodies (ICA) and insulin autoantibodies (IAA) were observed, unlike the high prevalence rates in Caucasian populations. In this report, we have measured other autoimmune markers (thyroid autoantibodies, thyrotrophin [TSH] receptor antibodies, rheumatoid factor and anti-dsDNA antibodies) to assess the extent of autoimmunity in our newly diagnosed diabetes patients and those with long-standing diabetes. Results indicate that there is a raised prevalence of thyroid autoantibodies in diabetics compared to the general population. Thyroid autoantibodies occurred in 24.3% (28/115) of the patients; thyroid microsomal antibodies (16.5%, 19/115) was much higher than for thyroglobulin antibodies (1.7%, 2/115). Prevalence rates of thyroid autoantibodies were lower in diabetics who were newly diagnosed (21.6%, 11/51), compared to those with long-standing disease (25.5%, 14/55). Three patients (3/9) with gestational diabetes were also positive for thyroid autoantibodies. TSH receptor antibodies associated with Graves' disease, were found in two patients. However, they also had thyrotoxicosis. Five patients (4.3%, 5/115) were detected with rheumatoid factor, but were clinically asymptomatic. Anti-dsDNA antibodies were not detected in any of the subjects. The presentation of thyroid autoantibodies or rheumatoid factor with age did not coincide with diabetes-associated ICA and IAA. It may mean that inspite of prevalence of subclinical autoimmunity in diabetes, autoimmunity against beta-cell lesions is not associated with the overall autoimmune tendency in our diabetes.

Adolescent↗

PubMed1990

Epidemiology of diabetes mellitus in the Asia-Pacific region.

The complex interaction between genetic and environmental factors in the causation of diabetes mellitus is well illustrated by the epidemiology of diabetes in the Asia-Pacific region. Among the Chinese, the prevalence of diabetes is uniformly higher among Chinese living outside China than in the Chinese in The People's Republic of China. Similarly among the Indians, the prevalence of diabetes is universally higher in those who have settled outside India than in Indians in India. In the Pacific populations, diabetes is much commoner among the Nauruans and Fiji Indians. Throughout the Asia-Pacific countries, economic progress and urbanisation have a uniformly deleterious effect on diabetes. A better understanding of the hereditary and environmental factors in the causation of diabetes is required to halt and reverse the rising prevalence of diabetes in the Asia-Pacific region.

Australia↗

PubMed1990

Pathogenesis of type 1 and type 2 diabetes mellitus.

The majority of patients with diabetes mellitus can be classified as suffering from either Type 1 or Type 2 diabetes. The pathogenetic pathways for these two categories of diabetes appear to be distinct and separate. Both forms of diabetes have a genetic as well as environmental component in their pathogenesis. Type 1 diabetes has a weaker genetic link; its association with HLA antigens is well established. Type 2 diabetes has a stronger genetic association but the exact gene or genes responsible is unknown. The environmental trigger in Type 1 diabetes may be a viral infection while urbanisation, obesity, physical inactivity and stress may trigger the development of Type 2 diabetes. Type 1 diabetes is a chronic autoimmune disease where beta cell destruction may occur over a number of years before clinical diabetes is diagnosed. Type 2 diabetes is the result of an interplay of relative insulin deficiency or a defect in insulin release together with insulin resistance. Hyperglycaemia perpetuates the problem of beta cell defect and insulin resistance. The understanding of pathogenesis of diabetes is the key to prevention and treatment of diabetes mellitus.

Autoantibodies↗

PubMed1990

Diabetes mellitus and its chronic complications in Singapore: an increasing healthcare problem.

We studied the prevalence of diabetes mellitus in Singapore and compared it to the study conducted ten years previously. A rise in prevalence rates from 2.0% to 4.7% was demonstrated. Impaired glucose tolerance (IGT) was studied for the first time, and a prevalence rate of 0.9% was found. Findings on chronic complications of diabetes were also reported. A high frequency of coronary heart disease and hypertension were detected in both diabetic and IGT subjects. Obesity and hyperlipidaemia were identified as important risk factors. This study demonstrates the scope and impact of diabetes mellitus as a major healthcare problem in Singapore. Strategies directed at prevention and control of this disease needs to be implemented so as to check its rising trend.

Adolescent↗

PubMed1990

Physical activity in Chinese, Malays and Indians in Singapore.

A population based survey has measured levels of physical activity by questionnaire in persons aged 18 to 69 years in Singapore. Levels of physical activity were classified into high, medium and low based on activity in leisure and at work. The only ethnic difference was that for males a higher proportion were classified as "high" activity in Malays (24.8%) than Chinese (16.0%) and Indians (18.1%). For the overall 18 to 69 age group, it was found that for males, the proportions in the "low" category were Chinese 80%, Malays 70% and Indians 75% while for females it was 95% in all three ethnic groups. As physical activity of sufficient intensity is important in disease prevention and health promotion, more needs to be done on educating the public in Singapore about the benefits of regular exercise.

Adolescent↗

PubMed1990

Alcohol consumption in Chinese, Malays and Indians in Singapore.

A population based survey has measured alcohol consumption by questionnaire in persons aged 18 to 69 years in Singapore. The majority were "occasional/none" drinkers, being males (Chinese 87%, Malays 99% and Indians 80%) and females (Chinese 98%, Malays 100% and Indians 100%). "Heavy" consumption was uncommon in males (Chinese 0.6%, Malays 0% and Indians 1.3%) and absent in females, while "heavy/moderate" drinking was males (Chinese 5.7%, Malays 0.5% and Indians 3.8%) and females (Chinese 0.3%, Malays 0% and Indians 0%). For males, "light" drinking was highest in Indians (15.9%), then Chinese (7.8%) and then Malays (0.5%). This survey indicates that alcohol consumption is not yet a major public health problem in Singapore.

Adolescent↗

PubMed1990

Obesity and body mass indices in Chinese, Malays and Indians in Singapore.

A population based cross-sectional survey has measured body mass indices (BMIs) in Singapore and compared their means and the proportions who are overweight and obese amongst Chinese, Malays and Indians. For males there was little ethnic differences; for the 18-69 age group, the age-adjusted mean BMIs being Chinese 22.3, Malays 23.1 and Indians 22.5. However for females, Malays and Indians were considerably more obese than Chinese; for the 18-69 age group the age-adjusted mean BMIs in Malays (25.1) and Indians (24.6) were significantly greater (p less than 0.001) than in Chinese (22.2). The proportions categorised as overweight or obese (BMI equal to or more than 26 in males and 25 in females) were males (Chinese 16.7%, Malays 22.4%, and Indians 14.0%) and females (Chinese 21.2%, Malays 51.5%, and Indians 42.0%). Health education on the harmful effects of obesity should be targeted especially on Malay and Indian females.

Adolescent↗

PubMed1989

HLA Bw46 and DR9 associations in Graves' disease of Chinese patients are age- and sex-related.

The HLA-A, -B antigens in 159 Chinese patients with Graves' disease were compared with those of 330 controls. The HLA-DR antigens of the patients were also studied in 100 normals. Analysis of the increased prevalence of Bw46, according to the sex and age of onset of disease of the patients, showed that the strong association of Bw46 resided with male patients (n = 58), Pc = 0.0000052, RR = 4.2. Although the frequency of Bw46 was also increased in female patients (n = 101), it was statistically not significant. For the DR9 antigens, the strong association with male patients was also observed, viz. Pc = 0.019, RR = 3.2. Males also had higher risks of Graves' disease if they had homozygous Bw46 at presentation. Further analysis by age of onset of disease revealed the segregation of significant association with Bw46 for the males at 1-19 yr, Pc = 0.0011, RR = 17.5 HLA associations (Bw46 and DR9) with Graves' disease in Chinese are observed primarily in males, especially those whose known ages of onset of the disease are between 1-19 yr (Bw46).

Adult↗

PubMed1989

Restoration of spermatogenesis with pulsatile gonadotrophin releasing hormone therapy in hypogonadotrophic hypogonadism of traumatic etiology.

Head trauma is one of the rarest reported causes of hypogonadotrophic hypogonadism and treatment of this condition with pulsatile gonadotrophin releasing hormone (GnRH) has not been previously described. A 36-year-old man with azoospermia from hypogonadotrophic hypogonadism following head trauma was given pulsatile GnRH therapy. 10 micrograms of GnRH was administered every 90 minutes through a subcutaneous catheter in the abdominal wall. After 15 months, the ejaculate contained 34 x 10(6) spermatozoa/ml of semen. Prolonged pulsatile GnRH therapy can restore gonadal function in males with hypogonadotrophic hypogonadism of traumatic etiology. Our experience adds to the growing spectrum of hypothalamic disorders causing hypogonadism that is amenable to treatment by this method.

Adult↗

PubMed1989

Syndrome of cerebellar ataxia and hypogonadotrophic hypogonadism: evidence for pituitary gonadotrophin deficiency.

Familial cerebellar ataxia with hypogonadotrophic hypogonadism is a rare condition. Two affected siblings in a sibship of three were studied and found to have low plasma gonadotrophin levels. No rise in gonadotrophin levels was demonstrable after repeated stimulation with LHRH. The pattern of TSH and prolactin responses to TRH stimulation suggest hypothalamic dysfunction. The results clearly identify the cause of hypogonadism to be due to a defect in production or release of gonadotrophins by the pituitary gland and suggest that hypogonadism is part of a greater endocrine disturbance involving both the hypothalamus and pituitary.

Adolescent↗