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Human Fc gamma receptor IIA (FcgammaRIIA) genotyping and association with systemic lupus erythematosus (SLE) in Chinese and Malays in Malaysia

Yap SN, Phipps ME, Manivasagar M, Tan SY, Bosco JJ

Lupus, 1999;8(4):305-10.
PMID: 10413210 DOI: 10.1191/096120399678847876

SLE is an autoimmune and polygenic disorder characterized by an accumulation and deposition of immune complexes. Several studies have indicated differential impact of FcgammaR polymorphism genotypes in different ethnic groups studied. The Fc receptor for IgG class IIA gene (FcgammaRIIA) occurs in two allelic forms. The allele FcgammaRIIA-H131 encodes a receptor with a histidine at the 131 amino acid position; the other allele FcgammaRIIA-R131 encodes an arginine. This polymorphism is believed to determine the affinity of the receptor for hIgG2 in immune complexes. FcgammaRIIA-H131 has a higher capacity for hIgG2 compared to FcgammaRIIA-R131 as measured by in vitro studies of insoluble immune complex clearance. We have investigated the polymorphism for FcgammaRIIA using a novel polymerase chain reaction-allele specific primer (PCR-ASP) method designed specifically to distinguish the two allelic forms. Our studies were based on 175 Chinese and 50 Malays SLE patients as well as 108 and 50 ethnically matched healthy controls for the respective groups. Analysis of the data (chi2 test with Yates correction factors and odds ratios) revealed that there were no significant differences between SLE patients and controls. We have not found evidence of a protective effect conferred by FcgammaRIIA-H131 in the ethnic groups studied.
Fulltext The occurence of point mutations in the dihydrofolate reductase-thymidylate synthase (DHFR) gene in Thai isolates of Plasmodium falciparum

Lim PK, Looareesuwan S, Chindanond D, Saleh AM, Tan SK

Southeast Asian J. Trop. Med. Public Health, 1998 Sep;29(3):525-8.
PMID: 10437950
Selection of high affinity ligands to hepatitis B core antigen from a phage-displayed cyclic peptide library

Ho KL, Yusoff K, Seow HF, Tan WS

J Med Virol, 2003 Jan;69(1):27-32.
PMID: 12436474

M13 phages that display random disulfide constrained heptapeptides on their gpIII proteins were used to select for high affinity ligands to hepatitis B core antigen (HBcAg). Phages bearing the amino acid sequences C-WSFFSNI-C and C-WPFWGPW-C were isolated, and a binding assay in solution showed that these phages bind tightly to full-length and truncated HBcAg with K D rel values less than 25 nM, which is at least 10 orders of magnitude higher than phage carrying the peptide sequence LLGRMK selected from a linear peptide library. Both the phages that display the constrained peptides were inhibited from binding to HBcAg particles by a monoclonal antibody that binds specifically to the immunodominant region of the particles. A synthetic heptapeptide with the amino acid sequence WSFFSNI derived from one of the fusion peptides inhibits the binding of large surface antigen (L-HBsAg) to core particles with an IC50 value of 12 +/- 2 microM. This study has identified a smaller peptide with a greater inhibitory effect on L-HBsAg-HBcAg association.
Predictive factors by multivariate analysis for colorectal cancer in Malaysian patients undergoing colonoscopy

Tan YM, Rosmawati M, Ranjeev P, Goh KL

J Gastroenterol Hepatol, 2002 Mar;17(3):281-4.
PMID: 11982698

BACKGROUND: The majority of colorectal cancers are still diagnosed in patients who present with symptoms especially in countries where colorectal screening programs are not practised. The aim of our study was to determine the predictive factors for colorectal cancer in patients referred for colonoscopy.
METHODS: A prospective study of 485 consecutive patients who underwent colonoscopy during a 22-month period was performed. All patients answered a detailed questionnaire. Indications for colonoscopy and the findings were recorded.
RESULTS: The mean age of the study population was 55.7 +/- 14.7 years. There were 221 (45.6%) males and 264 (54.4%) females. Sixty-five (13.4%) were Malays, 298 (61.4%) were Chinese and 112 (23.1%) were Indians. Multiple backward stepwise regression analysis revealed that independent predictors for colorectal cancer (odds ratio [95% CI]) were the presence of rectal bleeding (4.3 [4.0-8.0]) and iron deficiency anemia (4.0 [3.6-10.2]). In those aged 50 and over, male gender (4.5 [2.2-9.3]) and abdominal pain (3.1 [1.4-6.7]) were also significant positive predictors of cancer.
CONCLUSIONS: With the ever-increasing demand for gastrointestinal endoscopy, the appropriate utilization of colonoscopy is essential to afford prompt patient evaluation. Our study supports the need to prioritize the use of colonoscopy in patients with rectal bleeding and iron deficiency anemia. In the older patient where the background prevalence of colorectal cancer is higher, referral for colonoscopy is also justified.
Fulltext Chinese mothers intention to breastfeed, actual achievement and early postnatal experience

Teh SC, Chong SI, Tan HH, Ho J

Med J Malaysia, 2000 Sep;55(3):347-51.
PMID: 11200715

Thirty Chinese primiparous mothers were asked during the antenatal period their breastfeeding intention and then interviewed at delivery and 6 weeks post delivery. One mother had no intention to breastfeed. Ten mothers intended exclusive breastfeeding for one month and 19 for 6 weeks or more. At 6 weeks post delivery only 4 mothers were still breastfeeding. A total of 22 (73%) did not achieve their initial intention. For any future pregnancy, 5 chose exclusive breastfeeding, 22 complementary and 3 formula feeding. Chinese primiparous mothers have high breastfeeding intentions but the majority do not achieve them and their experience has discouraged them from exclusive breastfeeding in future pregnancies.
Cytogenetic analysis of invasive breast cancer: a study of 27 Asian patients

Tan PH, Lui WO, Ong P, Lau LC, Tao M, Chong Y

Cancer Genet. Cytogenet., 2000 Aug;121(1):61-6.
PMID: 10958943

Tumor cytogenetic analysis from 27 patients with breast cancer diagnosed at the Singapore General Hospital revealed complex karyotypic aberrations in 12 cases. The study group comprised 25 women and 2 men, ranging in age from 33 to 78 years (median 52 years). Ethnic distribution consisted of 22 Chinese, 3 Malaysian, and 2 Indian patients. Pathologic assessment disclosed 24 invasive ductal, 2 invasive mucinous, and 1 mixed invasive mucinous and ductal carcinomas. Histologic grading showed 3 grade 1, 10 grade 2, and 12 grade 3 tumors; 2 cancers were not graded, because they had been subjected to prior chemotherapy. Tumor sizes ranged from 1.5 to 10 cm (median 3 cm). Eleven cases were axillary node negative, whereas the remaining 16 node-positive cancers affected as many as 3 nodes in 8 cases and 4 or more nodes in another 8. Twenty cases demonstrated estrogen-receptor positivity, and 8 cases progesterone-receptor positivity. The spectrum of cytogenetic abnormalities involved chromosomes 1, 3, 6, 7, 8, 11, 16, and 17 and ranged from gains and deletions of both long and short arms, trisomy, monosomy, and other rearrangements. There was a trend toward the presence of karyotypic abnormalities in tumors of higher grade.
An epidemiological study of developmental dysplasia of the hip in infants in Singapore

Ang KC, Lee EH, Lee PY, Tan KL

Ann Acad Med Singap, 1997 Jul;26(4):456-8.
PMID: 9395810

The incidence of congenital dislocation of the hip (CDH) in Singapore and Malaysia has been reported as being lower than in the West. In our hospital, we have seen an increasing number of congenital hip dislocation as well as dysplastic hips. We undertook a prospective study from December 1989 to December 1994 of 20,000 live births. The neonates were all screened by a consultant neonatologist and the findings were confirmed by a consultant paediatric orthopaedic surgeon. All babies had plain X-rays at 3 months and an acetabular index (AI) of 30 degrees or more was considered dysplastic. All babies with positive signs were followed up for 1 year and again had radiographs taken at 1 year. Comparison of plain X-rays and ultrasound assessment in a subgroup of 130 neonates showed that 64% of patients with AI > 20 degrees had hip dysplasia by ultrasonographic (alpha angle < 60 degrees) The incidence of dysplastic hips was 16.8 per 1000 live births. The overall incidence of neonates with dislocated hips was 4.7 per 1000 live births. The Malays were most affected with an incidence of 5.4 per 1000 live births. The incidence of developmental dysplasia of the hip in Singapore is higher than previously reported, with the Malays having the highest incidence. A significant number of babies with clicking hips have radiological evidence of acetabular dysplasia (AI > 30 degrees). One-third of the babies' hips were still dysplastic at 1 year of age. A well-organised screening programme with experienced examiners has proved to be useful in making early and accurate clinical diagnosis.
Population based standards for pulmonary function in non-smoking adults in Singapore

Chin NK, Ng TP, Hui KP, Tan WC

Respirology, 1997 Jun;2(2):143-9.
PMID: 9441128 DOI: 10.1111/j.1440-1843.1997.tb00070.x

Ethnic differences in lung function are well recognized, hence the use of normative data should therefore be based on reference equations that are derived specifically for different ethnic groups. We have collected data (n = 406) for population-based reference values of lung function from randomly selected samples of healthy non-smoking adults of both gender (aged 20-79 years) for each of the three major ethnic groups (Chinese, Malay and Indians) in Singapore. Lung function forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), FEV1/FVC, diffusion capacity (transfer factor) for carbon monoxide (DLCO), total lung capacity (TLC), residual volume (RV), RV/TLC and functional residual capacity (FRC) was measured using standardization procedures and acceptability criteria recommended by the American Thoracic Society. Lung function values were predicted from age, height, weight, body mass index (BMI) and transformed variables of these anthropometric measures, using multiple regression techniques. Ethnic differences were demonstrated, with Chinese having the largest lung volumes and flow rates, and Indians the smallest. These prediction equations provide improved and additional (TLC, RV, RV/TLC, FRC) population-based reference values for assessment of pulmonary health and disease in Singapore.
The role of transvaginal sonography in the diagnosis of placenta praevia

Tan NH, Abu M, Woo JL, Tahir HM

Aust N Z J Obstet Gynaecol, 1995 Feb;35(1):42-5.
PMID: 7771998 DOI: 10.1111/j.1479-828x.1995.tb01828.x

Transvaginal sonography was performed in 70 patients diagnosed to have placenta praevia by transabdominal sonography. The diagnosis was confirmed either by digital examination in theatre at term or operative finding at delivery. Forty-nine cases (70%) were correctly diagnosed to have placenta praevia by both modes of sonography. Transvaginal sonography ruled out placenta praevia in 12 cases (17%) thought to be placenta praevia by transabdominal ultrasound. Both transabdominal and transvaginal sonography demonstrated 'placental migration' in 4 cases (6%) which were no longer praevia at delivery. Five patients (7%) were erroneously believed to have placenta praevia by both sonographic techniques. Overall, the diagnostic accuracy of transvaginal sonography was 92.8% compared with 75.7% for transabdominal sonography. None of the subjects experienced any exacerbation of bleeding or other complications. The results suggest that transvaginal sonographic localization of the placenta is safe and superior to the transabdominal route.
Haemorrhagic disease in newborn and older infants: a study in hospitalized children in Kelantan, Malaysia

Choo KE, Tan KK, Chuah SP, Ariffin WA, Gururaj A

Ann Trop Paediatr, 1994;14(3):231-7.
PMID: 7825997

This is a retrospective study of the epidemiology, clinical features, laboratory findings, treatment and outcome of haemorrhagic disease in 42 Kelantanese infants who were admitted to Hospital Universiti Sains Malaysia during a 2-year period (1987-1988). Classical haemorrhagic disease of the newborn was the commonest presentation (48%), followed by early onset (29%) and late onset (24%) disease. Home deliveries accounted for 81% of the affected infants. Most of these babies were not given vitamin K at birth in contrast to those delivered in hospitals. All except one infant were breastfed. The six commonest presenting clinical features were pallor, jaundice, umbilical cord bleeding, tense fontanelle, convulsions and hepatomegaly. All the infants had prolonged prothrombin and partial thromboplastin times which were corrected by administration of vitamin K. Subdural haemorrhage was the commonest form of intracranial haemorrhage, followed by subarachnoid haemorrhage. The overall case fatality rate was 14%. The results of this study once again emphasize the value of vitamin K prophylaxis in the newborn.
Outcome prediction in early management of severe head injury: an experience in Malaysia

Selladurai BM, Jayakumar R, Tan YY, Low HC

Br J Neurosurg, 1992;6(6):549-57.
PMID: 1472321

The outcome of 109 patients with severe head injury was studied in relation to clinical and computed tomographic (CT) criteria on admission, after resuscitation. Age, Glasgow Coma Score (GCS) and state of pupils strongly correlated with outcome. The presence of hypothalamic disturbances, hypoxia and hypotension were associated with an adverse outcome. The CT indicators associated with poor outcome were perimesencephalic cistern (PMC) obliteration, subarachnoid haemorrhage, diffuse axonal injury and acute subdural haematoma. The prognostic value of midline shift and mass effect were influenced by concomitant presence of diffuse brain injury. For the subset of patients aged < 20 years, with GCS 6-8 and patent PMC (n = 21), 71.4% correct predictions were made for a good outcome. For the subset of patients aged > 20 years, with GCS 3-5 and partial or complete obliteration of PMC (n = 28), 89.3% correct predictions were made for a poor outcome.
T cell receptor beta chain RFLP in Chinese, Indians and Malays from Singapore

Tan JA, Tay JS, Aziz NB, Saha N

Hum. Hered., 1996 Jul-Aug;46(4):236-8.
PMID: 8807327

Restriction fragment length polymorphism (RFLP) of the gene encoding the beta chain of the human T cell receptor (TcR) was studied in three ethnic groups in Singapore by Southern blotting. Polymorphism in the beta chain gene was identified in BglII-digested DNA samples using a 770-bp TcR beta cDNA clone containing the joining and constant region segments. The TcR beta/BglII polymorphism was studied in 136 Chinese, 93 Indian and 88 Malay samples. The frequency of the less frequent allele (TcR beta*2) in all the ethnic groups was significantly lower (0.15-0.29, p < 0.01) than that in the Caucasians (0.46). Indians had a significantly lower frequency of this allele (0.15) than the Chinese (0.29) and Malays (0.26).
Gall bladder tumour, choledochal cyst and an anomalous pancreatico-biliary junction

Toufeeq Khan TF, Sherazi ZA, Tan YY

HPB Surg, 1995 Jun;8(3):185-6.
PMID: 7547622

This report highlights the association of a tumour in an acalculous gall bladder with an anomalous pancreatico-biliary junction (PBJ) and a type IVa choledochal cyst. Cholecystectomy and Rouxen-Y hepatico-jejunostomy (RHJ) was performed after division of the common bile duct (CBD) and excision of the dilated segment. The details of the case are presented and the role of an abnormal PBJ in gall bladder carcinogenesis is discussed.
Seasonal prevalence of air-borne pollen and spores in Kuala Lumpur, Malaysia

Ho TM, Tan BH, Ismail S, Bujang MK

Asian Pac J Allergy Immunol, 1995 Jun;13(1):17-22.
PMID: 7488339

Aerosampling using Rotorod samplers was conducted in the Institute for Medical Research, Kuala Lumpur, Malaysia, from December 1991 to November 1993. Samples were collected twice a week between 10.00 hours to 12.00 hours. Rods were stained and examined microscopically. A total of 8 and 20 types of pollens and mold spores were collected, respectively. More mold spores were collected than pollens. Grass pollen constituted more than 40 percent of total pollen counts. Gramineae pollen counts peaked in March and September. The most abundant mold spore was Cladosporium followed by Rust, Nigrospora, Curvularia and Smut. Cladosporium counts peaked in February and August. Rust counts peaked in June and December whereas counts for Nigrospora peaked in February and October. Highest counts of Smut were recorded in March and October. Curvularia counts peaked in January, June and September.
Fulltext The role of cytomegalovirus (CMV) infection in congenital diseases in Malaysia

Balasubramaniam V, Sinniah M, Tan DS, Redzwan G, Lo'man SG

Med J Malaysia, 1994 Jun;49(2):113-6.
PMID: 8090088

A previous cross-sectional serological survey of various age groups (0-55 years) of the Malaysian normal population showed that cytomegalovirus (CMV) infection is highly endemic in Malaysia. A total of 1,688 infants (0-4 months) with congenital abnormalities were screened for evidence of congenital CMV infection and the rest of the TORCHES (TOxoplasmosis, Rubella, Cytomegalovirus, HErpes simplex, Syphilis) group of congenital infections. Congenital CMV infection was detected in 193 (11.4%) infants which is significantly higher than the prevalence of congenital syphilis (4%), congenital rubella infection (3.7%), congenital toxoplasma (1.0%) and congenital herpes simplex virus infection (0%). Of the 193 cases, 10.4 per cent had CNS defects. We concluded that 1) congenital CMV appears to be the most important cause of congenital infections among the TORCHES diseases in Malaysia; and 2) secondary rather than primary infections or reactivation is responsible for most of the intrauterine CMV infection in Malaysia, as primary infection is usually associated with neurological involvement.
Fulltext Steroid-induced osteoporosis--a cause for concern?

Tan TT, Lau IS, Kong NC, Zainal AG

Malays J Pathol, 1997 Jun;19(1):27-33.
PMID: 10879239
Human herpesvirus-6 (HHV-6) DNA and virus-encoded antigen in oral lesions

Yadav M, Arivananthan M, Chandrashekran A, Tan BS, Hashim BY

J Oral Pathol Med, 1997 Oct;26(9):393-401.
PMID: 9385576

Archival oral tissues comprising 51 squamous cell carcinomas, 18 non-malignant lesions and 7 normal mucosa samples were investigated for human herpesvirus-6 (HHV-6)-encoded antigens and HHV-6 DNA. The virus-specific antigens were detected by an immunohistochemical method using monoclonal antibodies. Two further techniques used for HHV-6 DNA detection included the polymerase chain reaction (PCR) with virus-specific primers and in situ hybridization using digoxigenin-labelled oligonucleotides specific for HHV-6A and HHV-6B genotypes. A high proportion (79-80%) of the squamous cell carcinomas were positive for HHV-6 with the various detection methods. In cases of lichen planus and leukoplakia a high prevalence rate (67-100%) was noted with in situ hybridization and immunohistochemical techniques but a lower proportion (22-33%) was detected with the PCR method. All 7 normal tissues tested were negative for HHV-6. The HHV-6 variant B was found in 60% of the oral carcinoma tissues analysed. The study demonstrates the frequent presence of HHV-6 in neoplastic and non-malignant lesions of the oral cavity. While the role of HHV-6 in oral mucosal tissues remains to be determined, the in vitro tumorigenic potential of the virus suggests a possible role in the etiopathogenesis of oral lesions.
Prevalence of visual disorders in Chinese schoolchildren

Chung KM, Mohidin N, Yeow PT, Tan LL, O'Leary D

Optom Vis Sci, 1996 Nov;73(11):695-700.
PMID: 8950751

We performed a vision screening of 1883 Chinese schoolchildren from 4 schools around Kuala Lumpur in June 1990. The group contained 1083-males and 800 females. Visual acuity, refractive error, oculomotor balance, and axial length were measured. The prevalence of myopia in Chinese schoolchildren was found to be 37% in the 6- to 12-year age group and 50% in the 13- to 18-year age group. Approximately 63% of the sample had unaided visual acuity of 6/6 or better and 24% had unaided acuity of 6/12 or worse. Six hundred twenty-five students (33%) failed the vision screening test and were referred for further examinations. The group which failed the vision screening test and had the highest rate of referral (46%) was the 11- to 12-year-old age group. The most common visual disorder was uncorrected myopia, accounting for 38% of the referrals (235 students). Only 26% of the sample were wearing a spectacle correction.
Fulltext The spectrum of beta-thalassemia mutations in Malays in Singapore and Kelantan

Abdullah WA, Jamaluddin NB, Kham SK, Tan JA

Southeast Asian J. Trop. Med. Public Health, 1996 Mar;27(1):164-8.
PMID: 9031421

The spectrum of beta-thalassemia mutations in Malays in Singapore and Kelantan (Northeast Malaysia) was studied. Allele specific priming was used to determine the mutations in beta-carriers at -28, Codon 17, IVSI #1, IVSI #5, Codon 41-42 and IVSII #654 along the beta-globin gene. The most common structural hemoglobin variant in Southeast Asia, Hb E, was detected by DNA amplification with restriction enzyme (Mnl1) analysis. Direct genomic sequencing was carried out to detect the beta-mutations uncharacterized by allele-specific priming. The most prevalent beta-mutations in Singaporean Malays were IVSI #5 (45.83%) followed by Hb E (20.83%), codon 15 (12.5%) and IVSI #1 and IVSII #654 at 4.17% each. In contrast, the distribution of the beta-mutations in Kelantan Malays differed, with Hb E as the most common mutation (39.29%) followed by IVSI #5 (17.86%), codon 41-42 (14.29%), codon 19 (10.71%) and codon 17 (3.57%). The beta-mutations in Kelantan Malays follow closely the distribution of beta-mutations in Thais and Malays of Southern Thailand and Malays of West Malaysia. The AAC-->AGC base substitution in codon 19 has been detected only in these populations. The spectrum of beta-mutations in the Singaporean Malays is more similar to those reported in Indonesia with the beta-mutation at codon 15 (TGG-->TAG) present in both populations. The characterization of beta-mutations in Singaporean and Kelantan Malays will facilitate the establishment of effective prenatal diagnosis programs for beta-thalassemia major in this ethnic group.
Isozyme and morphological characteristics of the anaerobic fungus Piromyces mae isolated from the duodenum, rumen and faeces of sheep

Wong MV, Ho YW, Tan SG, Abdullah N, Jalaludin S

FEMS Microbiol Lett, 1995 Dec 01;134(1):9-14.
PMID: 8593960

Isolates of anaerobic fungi obtained from the rumen, duodenum and faeces of sheep were identified as Piromyces mae based on their morphological characteristics observed using light microscopy. There was no significant morphological variation among the isolates of P. mae from the rumen, duodenum and faeces. Isozymes of 12 isolates of P. mae (one each from the rumen, duodenum and faeces from 4 different sheep) were analysed by PAGE. A total of 12 isozymes were studied and 5 isozyme loci were successfully typed. They were malic enzyme, malate dehydrogenase, shikimate dehydrogenase, alpha-esterase and beta-esterase. All the isolates of P. mae regardless of whether they were from the rumen, duodenum or faeces or from different animals produced very similar isozyme banding patterns for each of the enzyme systems. The similar isozyme profiles of the isolates indicate that they are of the same species although they exist in different regions of the alimentary tract.

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