Ng Wai Yoong

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    Soluble T-cell markers and serum cytokines in type I (insulin-dependent) Diabetes mellitus
    (1995) Ng, W.-Y.; Thai, A.-C.; Lui, K.-F.; Yeo, P.P.B.; Cheah, J.-S.; MEDICINE
    Markers of cell-mediated immune activation were studied in 32 Chinese patients with recent-onset insulin-dependent diabetes mellitus (IDDM) as compared with 12 patients with recent-onset non-insulin-dependent diabetes mellitus (NIDDM) and 34 normal subjects. Sera were assessed for soluble markers of T-cell activation (sCD4, sCD8, sIL-2R); the cytokines (IL-1β, TNF-α, IL-2, IL-6), and T-cell subsets were also determined. Only 1 of the 32 IDDM patients had increased sCD4 levels, 5 had increased sCD8, and 3 had increased sIL-2R. None of the sera from NIDDM patients and control subjects showed such increased levels of soluble markers. Three IDDM patients had detectable IL-1β and this weakly so (
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    Diabetes mellitus and its chronic complications in Singapore: an increasing healthcare problem.
    (1990) Thai, A.C.; Yeo, P.P.; Lun, K.C.; Hughes, K.; Ng, W.Y.; Lui, K.F.; Cheah, J.S.; MEDICINE; COMMUNITY,OCCUPATIONAL & FAMILY MEDICINE
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    HLA Bw46 and DR9 associations in Graves' disease of Chinese patients are age- and sex-related
    (1989) Yeo, P.P.B.; Chan, S.H.; Thai, A.C.; Ng, W.Y.; Lui, K.F.; Wee, G.B.; Tan, S.H.; Lee, B.W.; Wong, H.B.; Cheah, J.S.; PHARMACOLOGY; MEDICINE; PAEDIATRICS; MICROBIOLOGY
    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).
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    Serum fructosamine concentrations in Singapore pregnant women.
    (1990-07) Thai, A.C.; Kek, L.P.; Ng, W.Y.; Viegas, O.A.; Rauff, M.; MEDICINE; OBSTETRICS & GYNAECOLOGY
    Serum fructosamine levels in women at pregnancy (28 weeks' gestation) were determined. The women (n = 99) also participated in an oral glucose tolerance test (OGTT) with a 75g liquid glucose load, to determine their glucose tolerance. At 32 weeks' gestation, seventy-nine of them repeated the oral glucose tolerance test and fructosamine measurement. Results showed that fructosamine levels in pregnant women with normal glucose tolerance (2.20 +/- 0.19 mmol/l, n = 76), were not statistically different from those with glucose intolerance (gestational diabetes: 2.19 +/- 0.22 mmol/l, n = 23) at 28 weeks' and also 32 weeks' gestation. However, serum fructosamine levels in pregnant women were lower than those in non-pregnant subjects. Serum fructosamine measurement is not a sufficiently sensitive test for diagnosis of gestational diabetes.
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    Evidence of autoantibodies to glutamic acid decarboxylase in oral fluid of type 1 diabetic patients
    (2002) Todd, A.L.; Ng, W.-Y.; Thai, A.C.; Lee, Y.S.; Loke, K.Y.; MEDICINE; PAEDIATRICS
    Circulating antibodies to glutamic acid decarboxylase (GADab) are a major indicator for autoimmune destruction of pancreatic islet cells (type 1 diabetes). Previously reported detection of GADab in oral fluid, however, was assayed by enzyme-linked immunosorbent assay (ELISA) with low diagnostic sensitivity and high non-specific binding. We re-assessed oral fluid GADab detection using a different sampling technique and a more robust assay. Type 1 diabetic subjects (n=32; mean age±SD: 13.9±3.7 years) provided Orasure® oral fluid and venous blood samples. Orasure® collections were assayed for total immunoglobulin G (IgG), then concentrated to 1/10 of their volume using mini-centrifugal protein concentrators. All samples were assayed by a GAD65 antibody radio-immunoprecipitation method. Oral fluid antibodies were detected (>99th percentile of radio-binding (%counts per min (%cpm)) for seronegatives) in 10/16 seropositive subjects, with %cpm (median: 6.4%; range: 4.6-25.8) significantly greater (P<0.001) than for seronegatives (median: 4.7%; range: 3.4-5.7). A highly significant correlation (Spearman's rho: 0.85; P<0.001) was demonstrated between %cpm of concentrates and respective serum titres for seropositive diabetics. Median IgG concentration of Orasure® collections was 22.8 mg/l (range: 9.4-168.0). GADab recovery from Orasure® collectors was estimated at 90%. This is the first confirmatory detection of diabetes-specific autoimmune markers in oral fluid. Acceptable correlation between concentrated oral fluid radio-binding and serum titre was achieved. Improved antibody recovery and assay re-optimisation could provide a basis for more extensive studies that may lead to an alternative non-invasive screening method for pre-clinical autoimmune diabetes. © 2002 Elsevier Science Ireland Ltd. All rights reserved.
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    Occurrence of antibodies to insulin in patients with autoimmune thyroid disease
    (1993) Ng, W.Y.; Thai, A.C.; Lui, K.F.; Cheah, J.S.; MEDICINE
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    Testosterone and leptin in a group of Chinese with and without diabetes
    (1999) Ng, W.Y.; Lui, K.F.; Thai, A.C.; MEDICINE
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    Rapid desktop method for the measurement of glycated haemoglobin HbA1c.
    (1993-12) Thai, A.C.; Ng, W.Y.; Lui, K.F.; Cheah, J.S.; MEDICINE
    A new desktop monoclonal antibody-based test system (Bayer Diagnostics DCA 2000) for quantitation of glycated haemoglobin HbA1c is described and evaluated. This method involves a monoclonal antibody to HbA1c which defines its specificity. It requires 9 minutes to complete, and shows good intra- and inter-run precisions (1.3%-3.7%), at 5 HbA1c levels tested--4.1%, 5.7%, 6.1%, 9.2% and 12.4%. Results from 81 blood samples obtained from diabetic patients (3.9%-13.2% HbA1c) showed excellent correlation with a laboratory-based ion-exchange HPLC technique (y = 1.03 [Lab] + 0.103%; Pearson coefficient, r = 0.99). The test can be performed either with a capillary fingerprick or venous blood sample. Only 1 microliter of blood volume is required. Comparison of HbA1c levels of 43 paired capillary and venous samples showed excellent correlation (y = 1.00 [venous] + 0.042%; r = 0.99). The HbA1c values obtained from a cohort of 37 healthy adults, mean (+/- SD) age 33 +/- 9.01 years, gave a value of 5.5 +/- 0.42%. The calculated 95% confidence limits are 4.7%-6.3%. This quick method provides 'stat' HbA1c results, which were hitherto not possible with the laboratory-based methods.
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    IgG1 subclass dominates autoimmune response to tyrosine phosphatase-like molecule IA-2 in Chinese type 1 diabetes patients
    (2002) Lui, K.F.; Cheah, J.S.; Thai, A.C.; Ng, W.Y.; MEDICINE
    Background and Aims: Islet autoantibodies are known markers for type 1 diabetes with an immune-mediated basis; their isotype or subclass profiles may also provide clues to changes in immune response during disease or after intervention. For ICAs and GADab, the IgG1 subclass consistently dominates in recent-onset disease. The aims of our study were to determine the isotype patterns for IA-2ab in Asian Chinese patients with autoimmune diabetes. Materiais anal Methods: From an initial screening of over 400 diabetes patients, 40 subjects (mean age 22.2 ± 15.8 years) with IA-2ab were enrolled for this study. IA-2ab was detected by radioimmunoassay of [35S]-labelled recombinant human IA-2ic(605-979). Of them, 31 (median age 15 years, range 2-57 years; 16 children) had clinical type 1 diabetes (that is, they required insulin at onset or within 1 year) with the majority having been recently diagnosed (< 1 year). The other 9 patients had clinical type 2 diabetes phenotype. Results: IA-2ab IgG subclasses determined with monospecific secondary antibodies showed that both type 1 diabetic adults and children had similarly non-restricted isotype patterns with a strong presence of IgG1-IA-2ab. The rank order was IgG1 > 3 > 2 > 4; 15 subjects had detectable IgG4-1A-2ab. Clonality of immune response determined with kappa/lambda chain-specific antibodies also showed a non-restricted pattern. Patients aged 38.2 ± 15.2 years with type 2 diabetes had broad patterns of isotypes - IgG1/3 was detected more frequently (n = 8) than IgG2/4 (n = 5). Of three patients on insulin treatment, one was also positive for GADab. The remaining 6 patients were on oral hypoglycaemic treatment, IA-2ab in type 2 diabetes showed a low titre compared to type 1 diabetes. Conclusions: Isotype responses to IA-2 had a strong IgG1 presence, similar to ICAs and GADab. With IgG3 subclass representation, a predominant Th1 milieu in the systemic environment is likely. There is no suggestion of differences in immune response to IA-2 between adults and children with type 1 diabetes.