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An in-house enzyme-linked immunoabsorbant assay for human growth hormone

Nazaimoon W, Ng ML, Bak K

Malays J Pathol, 1993 Jun;15(1):75-83.
PMID: 8277795

A simple, non-isotopic in-house enzyme-linked immunoabsorbant assay (ELISA) for human growth hormone (GH) was developed. The assay involved using in-house polyclonal anti-GH adsorbed onto 96-well microtitre plates, commercially prepared mouse monoclonal anti-GH, and goat anti-mouse IgG horseradish peroxidase detection system. Results of recovery and parallelism studies ranged from 95%-106% and 98%-101% respectively, of the expected values. The detection limit of the assay was 0.008 mIU/well or the equivalent to 0.4 mIU/L of undiluted serum. Intra- and interassay coefficients of variations were 4.8%-7.9% and 6.5%-8.7% respectively. Serum GH levels measured in this assay correlated well with those measured in established in-house radioimmunoassays (r = 0.985, p < 0.001) and immunoradiometric assay from NETRIA (r = 0.984, p < 0.001).
Thyroid eye disease--medical or surgical therapy?

Khalid BA, Ng ML

Ann Acad Med Singap, 1991 Mar;20(2):273-6.
PMID: 1883189

Thyroid eye disease is autoimmune in nature and associated with Graves' Disease. Autoantibodies to the 64 kDa antigen in thyroid membranes cross-react to the 64 kDa proteins in human eye muscle membranes. Antibody dependent cell mediated cytotoxicity against eye muscle cells are also found in patients with thyroid eye disease. The purpose of this paper is to review the treatment available and to share the authors' experience using cyclosporin A. In the majority of cases, thyroid eye disease is mild, manifest only as bilateral or unilateral proptosis, with/without grittiness of the eyes. This is usually treated conservatively with eye drops. If proptosis is more severe and there is incomplete closure of eyelids, epiphora and conjunctival injection, then lateral tarrsorrhaphy is usually effective, combined with use of eye pads and eye drops. The problem of diplopia can be treated conservatively with special lenses, or with surgical correction of tethered muscles. However when proptosis is severe, with raised intraocular pressure, severe chemosis and danger of blindness, then the choice of therapy is controversial: rapid decompression by surgical means or use of high doses of prednisolone. Most prefer prednisolone therapy initially, surgical decompression if it fails. Various other methods have been tried, aimed at the immunological nature of the disease, namely plasmapheresis, radiotherapy and immunosuppressive drugs such as cyclosporin, with variable success. Our experience with cyclosporin had been mixed and inconclusive.
Fasting growth hormone levels in diabetes mellitus

Nazaimoon WM, Ng ML, Khalid BA

Ann Acad Med Singap, 1993 Nov;22(6):861-3.
PMID: 8129344

Fasting serum growth hormone (GH) levels of different groups of diabetic patients were measured and compared to age-matched normal subjects. Insulin-dependent diabetes mellitus (IDDM) children (aged 12-17 years) were found to have significantly lower fasting GH levels than age-matched normal children (p < 0.001). In the adult age groups of 18-44 and 45-76 years, the IDDM patients showed increased fasting GH levels compared to age-matched normal subjects (p < 0.06 and p < 0.001 respectively) and non-insulin-dependent diabetes mellitus (NIDDM) patients (p < 0.05 and p < 0.001 respectively). The fasting GH levels of IDDM patients of the age group 18-44 years also showed significant correlations with glycated haemoglobin (r = 0.510, p = 0.002) and fasting blood sugar levels (r = 0.571, p = 0.01).
Collection and storage of capillary blood in glass fibre filters for glycated haemoglobin measurement by a microcolorimetric method

Ng ML, Sazali BS, Khalid BA

Ann. Clin. Biochem., 1991 Nov;28 ( Pt 6):613-7.
PMID: 1776812

A filter method for collection and storage of capillary blood spots for glycated haemoglobin (gHb) has been developed. Glass fibre filters (GFB) impregnated with 0.8 M boric acid were used to collect and store capillary blood. Haemoglobin from the dried blood spots was eluted into water and determined by Drabkin's method, while gHb in the eluates was determined by the microcolorimetric method. The intraassay coefficients of variation (CVs) were 4.5, 4.5 and 3.1% at 882, 1101 and 1704 pmol HMF/mg Hb, respectively. The corresponding inter-assay CVs were 8.6, 8.6 and 6.3%, respectively. A total of 63 paired capillary and venous blood samples were measured by both the direct and GFB method. The GFB method showed excellent correlation with the direct method (r = 0.948 and r = 0.994) after 7 and 14 days' storage at room temperature. The GFB method will enable prior collection and postage of blood samples by patients.
Enzyme immunoassay for simultaneous measurement of autoantibodies against thyroglobulin and thyroid microsome in serum

Ng ML, Rajna A, Khalid BA

Clin Chem, 1987 Dec;33(12):2286-8.
PMID: 3690847

A combined enzyme immunoassay (micro-ELISA) technique was established for measuring autoantibodies against thyroglobulin and thyroid microsome, involving the immuno-dot blot technique. Thyroglobulin and thyroid microsome antigens (1 g/L each) prepared from normal thyroids were spotted separately onto nitrocellulose membrane filter discs. Results by this method and those by immunofluorescence correlated well. The percentages of confirmed positives were 30% and 48% and the negatives were 58% and 46% (n = 50) for thyroglobulin and microsome, respectively. Testing these samples by gelatin agglutination gave a high percentage of false positives (up to 20%, n = 128) and hemagglutination testing yielded a high percentage of false negatives (up to 20%, n = 45). The titer of autoantibodies by the micro-ELISA technique was greater than by agglutination. This technique is highly specific and sensitive.
Fulltext Piloting an Asia Pacific Research Forum (pASPAREF)

Tan NC, Ng CJ, Ng M

Asia Pac Fam Med, 2002;1(2&3):110.
Age and gender effect on the growth of bone marrow stromal cells in vitro

Shamsul BS, Aminuddin BS, Ng MH, Ruszymah BH

Med J Malaysia, 2004 May;59 Suppl B:196-7.
PMID: 15468885

Bone marrow harvested by aspiration contains connective tissue progenitor cells which can be selectively isolated and induced to express bone phenotype in vitro. The osteoblastic progenitor can be estimated by counting the number of cells attach using the haemacytometer. This study was undertaken to test the hypothesis that human aging is associated with a significant change on the number of osteoblastic progenitors in the bone marrow. Bone marrow aspirates were harvested from 38 patients, 14 men (age 11-70) and 24 women (age 10-70) and cultured in F12: DMEM (1:1). In total 15 bone marrow samples have been isolated from patients above 40 years old (men/women) of age. Fourteen (93.3%) of this samples failed to proliferate. Only one (6.7%) bone marrow sample from a male patient, aged 59 years old was successfully cultured. Seventy percent (16/23) of the samples from patient below than 40 years old were successfully cultured. However, our observation on the survival rate for cells of different gender from patient below 40 years old does not indicate any significant difference. From this study, we conclude that the growth of bone marrow stromal cells possibly for bone engineering is better from bone marrow aspirates of younger patient.
The effect of cassava leave intake on thyroid hormone and urinary iodine

Osman BA, Ng ML, Bakar AA, Khalid BA

East Afr Med J, 1993 May;70(5):314-5.
PMID: 8306912

The effect of consuming large amounts of cassava leaves on thyroid function and urinary iodine was studied. Twenty volunteers were given 200 gm of boiled cassava leaves twice a day for 12 consecutive days. Thyroid hormones triiodothyronine and thyroxine were significantly lower by 9 days. Urinary iodine excretion was also significantly decreased. Cassava leaves, consumed in large amounts by aborigines, probably caused goitres by decreasing iodine absorption.
Presence of pro-opiomelanocortin peptides and corticotropin-releasing factor in human placenta

Ng ML, Healy DL, Rajna A, Fullerton M, O'Grady C, Funder JW

Malays J Pathol, 1996 Jun;18(1):59-63.
PMID: 10879226

Immunoreactive adrenocorticotropin (ACTH), beta-endorphin (BEP) and corticotropin-releasing factor (CRF) were detected in human term placenta obtained from elective Caesarian surgery. The concentrations of ACTH, BEP and CRF in placenta detected by radioimmunoassay (RIA) were 2.83 +/- 0.36, 0.52 +/- 0.05 and 0.56 +/- 0.15 ng/g wet weight of tissue respectively. Pro-opiomelanocortin (POMC) peptides were also detected in the amnion and chorion membranes and in the decidua. The concentrations of ACTH were 1.72 +/- 0.20, 4.43 +/- 0.39 and 5.80 +/- 0.17 ng/g and the levels of BEP were 0.42 +/- 0.18, 0.65 +/- 0.20 and 3.66 +/- 1.10 ng/g in the amnion, chorion and decidua respectively. In contrast to placenta, immunoreactive CRF was not detected in the amnion, chorion and decidua. Immunoreactive N-acetylated BEP was also not detected in all the placental subfractions. Comparison of the amounts of both ACTH and BEP in the various placental components indicated the following distribution: decidua > chorion > placenta > amnion. In decidua, POMC peptides were present in an equi-molar ratio but in the other three placental fractions, ACTH levels were three to five-fold higher than BEP. In immunohistochemical studies, only a positive staining for ACTH was obtained for decidua. Our results confirm the presence of POMC peptides and CRF in placenta and their physiological roles in pregnancy and parturition.
Measurement of androstenedione levels by an in-house radioimmunoassay

Lo MS, Ng ML, Wu LL, Khalid BA

Malays J Pathol, 1996 Jun;18(1):53-8.
PMID: 10879225

An in-house radioimmunoassay (RIA) for the measurement of androstenedione levels in serum was established and validated. Levels of androstenedione were measured by RIA using serum samples from various normal population groups and patients with congenital adrenal hyperplasia (CAH). Analytical recovery and linearity results were > 95%, while intra- and inter-assay CVs were < 10% and < 22% respectively. The assay sensitivity was 0.5 nmol/l or 25 fmol/tube. In normal population groups, the highest androstenedione levels were found in preterm neonates (1.6-12.4 nmol/l), followed by adult females (1.5-10.2 nmol/l), adult males (1.6-8.0 nmol/l) and term neonates (0.8-8.8 nmol/l), while the lowest values were observed in prepubertal children (0.5-3.4 nmol/l). There were no significant differences in diurnal variation and between follicular and luteal phases. The range of androstenedione levels in untreated or poorly controlled CAH patients (7.6-355.0 nmol/l, median 42.5 nmol/l, n = 20) were significantly higher (p < 0.001) than the upper normal limit of 3.4 nmol/L for prepubertal children. The normal androstenedione reference ranges for paediatric and adult groups have thus been established.
Usefulness and limitations of thyrotropin measurements as a first-line test for follow-up of Graves' patients

Ng ML, Tan TT, Roslan BA, Rajna A, Khalid BA

Ann Acad Med Singap, 1993 Jul;22(4):569-72.
PMID: 7504901

We evaluated the usefulness of sensitive thyrotrophin hormone (TSH) measurements in determining the thyroid status in the follow-up of Graves' patients undergoing medical treatment with thionamides. Out of a total of 186 serum samples tested, TSH levels were suppressed in 123 (66.1%), normal in 32 (17.2%) and elevated in 31 (16.7%) cases. Total T4, or T3 or both were elevated only in 97 (74.8%) cases of TSH-suppressed patients, indicating that TSH is less discriminatory as a first-line test for patients under treatment due to the hypothalamic-pituitary lag period. No comparisons with free T4 or free T3 were done in this study. Both total T4 (120 +/- 28 nmol/l) and TBII (23 +/- 21%) levels were significantly greater (p < 0.02) in the euthyroid group with suppressed TSH. This may suggest that persistence of a thyrotoxic state may still be present.
Fulltext Evaluation of suppression of growth hormone levels following a 75g oral glucose tolerance test

Nazaimoon WM, Ng ML, Satgunasingam N, Khalid BA

Med J Malaysia, 1992 Jun;47(2):103-9.
PMID: 1494329

Growth hormone (GH) levels were measured after a 75g oral glucose load (OGTT) in normal adults, patients with impaired glucose tolerance (IGT), insulin-dependent diabetes mellitus (IDDM) and acromegaly. Nadir GH levels at 2-hour post-OGTT in normal subjects ranged from 0.4 to 8.4 mIU/L, the 95% confidence interval being 0.4-4.4 mIU/L. In IGT and IDDM subjects basal fasting GH levels were not significantly different from normal and did not alter during OGTT. The high fasting GH level measured in one each of the IGT and IDDM patients was suppressible at 1-hour after glucose intake. In contrast, acromegalic patients had elevated fasting GH levels (11.8-178 mIU/L) although in 3 patients, the levels were mildly elevated and overlapped with normal. OGTT failed or only partially suppressed GH secretion in all acromegalics. Therefore, elevated fasting GH levels are not diagnostic and OGTT is required for accurate diagnosis and assessment of treatment of acromegalic patients.
Glycaemic and insulin responses of diabetic patients to traditional Malaysian meals and the effect of guar gum

Khalid BA, Lee LF, Samad AH, Ng ML

Asia Pac J Clin Nutr, 1996 Dec;5(4):239-43.
PMID: 24394617

The aims of the project were to determine the glycaemic and insulin responses of non-insulin dependent diabetic patients (NIDDM) to 3 traditional Malaysian meals compared to oral glucose, and to determine whether guar gum would affect these responses. Patients with NIDDM were tested with 75 g oral glucose and three common breakfast meals of the three main ethnic groups of Malaysia. When compared with the oral glucose group, significantly by lower blood glucose responses were seen at 90 and 120 minutes post prandial for nasi lemak (p<0.05) and at 60, 75 and 90 minutes for mee sup (p<0.05). No significant difference was seen for roti telur. There was no significant difference in plasma glucose at any time point of the study when the three test meals were compared with each other. Addition of 5g granulated guar gum mixed with water taken prior to the glucose significantly lowered the plasma glucose at 60, 120 and 150 minutes postprandially (p<0.05). Similarly for the test meals, guar gum significantly lowered plasma glucose concentration between 15 and 45 minutes (p<0.03) postprandial for nasi lemak and between 15 and 30 minutes (p<0.03) for mee sup but not with roti telur. With addition of guar gum, there was no significant change of insulin responses with the three meals but a significant increase was seen at 30 minutes (p<0.02) after ingestion of glucose.
Fulltext Hyperthyroid graves disease--a 5 year retrospective study

Tan TT, Ng ML, Wu LL, Khalid BA

Med J Malaysia, 1989 Sep;44(3):224-30.
PMID: 2626137

The clinical, biochemical and immunological features of 180 patients with hyperthyroid Graves' disease managed at the Universiti Kebangsaan Malaysia (UKM) Endocrine Clinic from 1983 to 1987 were examined. The prevalence of the disease is highest in Chinese and lowest in Indians. The female: male ratio is 2.8:1. Hypokalaemic periodic paralysis and hypercalcaemia were present in 5.0% and 1.7% of the cases respectively. Pretibial myxoedema was extremely rare. Thyrotropin - binding inhibitory immunoglobulins, anti-thyroglobulin and anti-microsome antibodies were positive in 61.5%, 25.8% and 42.3% of the patients respectively. A eumetabolic state could be achieved in the majority of patients with antithyroid drugs alone. Definitive therapy with subtotal thyroidectomy or radioiodine were needed in 31.3% of cases.
Effects of Lugol's solution on thyroid function in normals and patients with untreated thyrotoxicosis

Tan TT, Morat P, Ng ML, Khalid BA

Clin Endocrinol (Oxf), 1989 Jun;30(6):645-9.
PMID: 2591064

Thirty-eight normal volunteers and 10 patients with untreated thyrotoxicosis were each given 0.5 ml of Lugol's solution daily for 10 days. On days 0, 5, 10, 15 and 20, serum levels of T4, free T4, T3 and TSH (by sensitive immunoradiometric assay) were measured. In normal subjects, the serum concentrations of free T4 declined significantly at day 10 while TSH levels were significantly increased at days 5, 10 and 15. Serum levels of T4 and T3 did not change significantly. All the observed changes took place within the limits of normal ranges for the hormones mentioned. In contrast, in the thyrotoxic subjects, both T4 and T3 were significantly decreased at days 5 and 10, while serum TSH remained below detection limit (0.14 mU/l) throughout the study. Short exposure to excessive iodide in normal subjects affects T4 and T3 release and this effect could be partially overcome by compensatory increase in TSH. In thyrotoxicosis, lack of compensatory increase in TSH results in rapid decreases in T4 and T3 levels. The integrity of the hypothalamo-pituitary-thyroidal axis may be effectively assessed by measuring TSH response to iodide suppression, using a highly sensitive immunoradiometric assay.
pS2 expression in infiltrating ductal carcinoma of the breast correlates with oestrogen receptor positivity but not with histological grade and lymph node status

Looi LM, Azura WW, Cheah PL, Ng MH

Pathology, 2001 Aug;33(3):283-6.
PMID: 11523925

This investigation was carried out to gain insight into the prevalence of pS2 expression in invasive ductal breast carcinoma in the Malaysian population and its correlation with oestrogen receptor (ER) protein expression and tumour aggressiveness. Seventy consecutive infiltrating ductal breast carcinomas treated with mastectomy and axillary lymph node clearance were investigated, using the standard avidin-biotin complex immunoperoxidase method with microwave antigen retrieval and commercial monoclonal antibodies (Dako), for expression of pS2 and human ER. This was correlated against histological grade (modified Bloom and Richardson) and the presence of axillary lymph node metastasis of these carcinomas. Four (5.7%) were grade 1, 40 (57.1%) grade 2 and 26 (37.1%) grade 3 tumours. A total of 45 (64%) showed histological evidence of axillary lymph node metastasis. Forty (57%) were ER-positive, while 31 (44%) were pS2-positive. There was a statistically significant correlation between pS2 and ER expressions (chi2-test with Yates correction: P<0.005). There was no correlation between pS2 expression and histological grade (P>0.1) and the presence of lymph node metastasis (P>0.1). Our findings support the views that pS2 may be a co-marker of endocrine responsiveness in invasive breast cancer and that it does not influence breast cancer biology in terms of potential for metastatic spread.
Characteristics and clinical applications of Wharton's jelly-derived mesenchymal stromal cells

Liau LL, Ruszymah BHI, Ng MH, Law JX

Curr Res Transl Med, 2020 01;68(1):5-16.
PMID: 31543433 DOI: 10.1016/j.retram.2019.09.001

Mesenchymal stromal cells (MSCs) are widely used in the clinic because they involve fewer ethical issues and safety concerns compared to other stem cells such as embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs). MSCs derived from umbilical cord Wharton's jelly (WJ-MSCs) have excellent proliferative potential and a faster growth rate and can retain their multipotency for more passages in vitro compared to adult MSCs from bone marrow or adipose tissue. WJ-MSCs are used clinically for repairing tissue injuries of the spinal cord, liver and heart with the aim of regenerating tissue. On the other hand, WJ-MSCs are also used clinically to ameliorate immune-mediated diseases based on their ability to modulate immune responses. In the field of tissue engineering, WJ-MSCs capable of differentiating into multiple cell lineages have been used to produce a variety of engineered tissues in vitro that can then be transplanted in vivo. This review discusses the characteristics of WJ-MSCs, the differences between WJ-MSCs and adult MSCs, clinical studies involving WJ-MSCs and future perspectives of WJ-MSC research and clinical applications. To summarize, WJ-MSCs have shown promise in treating a variety of diseases clinically. However, most clinical trials/studies reported thus far are relatively smaller in scale. The collected evidence is insufficient to support the routine use of WJ-MSC therapy in the clinic. Thus, rigorous clinical trials are needed in the future to obtain more information on WJ-MSC therapy safety and efficacy.
Fulltext Tactile perception of pleasantness in relation to perceived softness

Pasqualotto A, Ng M, Tan ZY, Kitada R

Sci Rep, 2020 07 07;10(1):11189.
PMID: 32636415 DOI: 10.1038/s41598-020-68034-x

The sense of touch allows us to infer objects' physical properties, while the same input also produces affective sensations. These affective sensations are important for interpersonal relationships and personal well-being, which raises the possibility that tactile preferences are adapted to the characteristics of the skin. Previous studies examined how physical properties such as surface roughness and temperature influence affective sensations; however, little is known about the effect of compliance (physical correlate of softness) on pleasantness. Thus, we investigated the psychophysical link between softness and pleasantness. Pieces of human skin-like rubber with different compliances were pressed against participants' fingers. Two groups of participants numerically estimated the perceived magnitude of either pleasantness or softness. The perceived magnitude of pleasantness and softness both increased monotonically as a function of increasing object compliance, levelling off at around the end of the stimulus range. However, inter-subject variability was greater for pleasantness than for perceived softness, whereas the slope of the linear function fit to the magnitude estimates was steeper for softness than for pleasantness. These results indicate that object compliance is a critical physical determinant for pleasantness, whereas the effect of compliance on pleasantness was more variable among individuals than the effect on softness was.
Telomerase activation and human papillomavirus infection in invasive uterine cervical carcinoma in a set of Malaysian patients

Cheah PL, Looi LM, Ng MH, Sivanesaratnam V

J Clin Pathol, 2002 Jan;55(1):22-6.
PMID: 11825919

AIM: Telomerase activity was studied in invasive uterine cervical carcinoma to assess whether it was activated during cervical malignant transformation and to look for a possible association with human papillomavirus (HPV) infection in a set of Malaysian patients.
METHODS: Histologically confirmed invasive cervical carcinoma and benign cervices were assayed for telomerase activity using a commercial telomerase polymerase chain reaction (PCR) enzyme linked immunosorbent assay kit. The same cases were subjected to PCR detection of HPV using type specific (HPV types 6b, 11, 16, and 18) followed by L1 open reading frame (ORF) consensus primers.
RESULTS: HPV was detected in 18 (13 HPV-16, one HPV-6b, four only L1 ORF) of 20 invasive cervical carcinoma and one (only L1 ORF) of 19 benign cervices. Raised telomerase activity (A(450 nm) > 0.215) was detected in 11 cervical carcinomas, with A(450 nm) ranging between 0.238 and 21.790 (mean, 3.952) in positive squamous carcinomas, whereas A(450 nm) was only 0.222 in the one positive adenosquamous carcinoma. Five of 11 cervical carcinomas in stage I, three of six in stage II, both in stage III, and the only case in stage IV showed telomerase activation. Increased telomerase activity was noted in five of the 12 lymph node negative, five of the seven lymph node status unknown cases, and the one case with presumed lymph node metastasis. Ten of 18 HPV positive and one of two HPV negative cervical carcinomas showed telomerase upregulation.
CONCLUSIONS: Telomerase is activated in invasive cervical carcinoma. Although larger studies are needed, there seems to be no clear association between telomerase upregulation and HPV status, although there is a suggestion of increased telomerase activity in squamous carcinomas and late stage disease.
Vision loss in an immunocompetent child post varicella infection: A case report

Lee SC, Ng M, Tan CL, Ting SL

Malays Fam Physician, 2020;15(1):54-57.
PMID: 32284807

Chickenpox may lead to several neurological complications. Optic neuritis is one of the complications which has rarely been described, especially in immunocompetent individuals. We report a case of an 11-year-old immunocompetent girl who presented with sudden onset bilateral vision loss three weeks after varicella eruption. Ophthalmic examination revealed bilateral optic disc edema. Diagnosis of bilateral optic neuritis secondary to varicella was established based upon the preceding medical history, supported with clinical and radiological findings.

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