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A 52-year-old woman with recurrent hemoptysis

Lim KH, Lim YC, Liam CK, Wong CM

Chest, 2001 Mar;119(3):955-7.
PMID: 11243981
Use of artificial neural networks to predict drug dissolution profiles and evaluation of network performance using similarity factor

Peh KK, Lim CP, Quek SS, Khoh KH

Pharm Res, 2000 Nov;17(11):1384-8.
PMID: 11205731

PURPOSE: To use artificial neural networks for predicting dissolution profiles of matrix-controlled release theophylline pellet preparation, and to evaluate the network performance by comparing the predicted dissolution profiles with those obtained from physical experiments using similarity factor.
METHODS: The Multi-Layered Perceptron (MLP) neural network was used to predict the dissolution profiles of theophylline pellets containing different ratios of microcrystalline cellulose (MCC) and glyceryl monostearate (GMS). The concepts of leave-one-out as well as a time-point by time-point estimation basis were used to predict the rate of drug release for each matrix ratio. All the data were used for training, except for one set which was selected to compare with the predicted output. The closeness between the predicted and the reference dissolution profiles was investigated using similarity factor (f2).
RESULTS: The f2 values were all above 60, indicating that the predicted dissolution profiles were closely similar to the dissolution profiles obtained from physical experiments.
CONCLUSION: The MLP network could be used as a model for predicting the dissolution profiles of matrix-controlled release theophylline pellet preparation in product development.
Estimated coefficient of variation values for sample size planning in bioequivalence studies

Yuen KH, Wong JW, Yap SP, Billa N

Int J Clin Pharmacol Ther, 2001 Jan;39(1):37-40.
PMID: 11204936

OBJECTIVE: The aim of the present communication is to provide information regarding the intrasubject coefficent of variation obtained from 30 bioequivalence studies covering 16 drugs which can be used for estimation of sample size. Additionally, an attempt was also made to estimate the test power of each of the studies conducted.
METHODS: The intrasubject coefficient of variation was estimated from the residual mean square error obtained from analysis of variance of the parameters AUC0-infinity, Cmax and Cmax/AUC0-infinity after logarithmic transformation. The test power in the analyses of the above parameters was subsequently estimated using nomograms provided by Diletti et al. [1991].
RESULTS AND CONCLUSION: Thirty products covering 16 drugs were studied in which 22 were immediate-release (including one dispersible tablet) and 8 were sustained-release formulations. The intrasubject coefficient of variation for the parameter AUC0-infinity was smaller than Cmax, and hence considerably more studies were able to attain a power of greater than 80% using 12 volunteers for the AUC0-infinity, compared to the Cmax. However, the variability in the Cmax could be reduced by using the parameter Cmax/ AUC0-infinity, and thus, provide a more realistic estimation of sample size, since the latter reflects only the rate of absorption and not both the rate and extent as in the case of Cmax [Endrenyi et al. 1991].
Fulltext Ureteral injuries in an obstetric and gynaecology teaching hospital

Yeong CT, Lim TLW, Tan KH

Med J Malaysia, 1998 Mar;53(1):51-8.
PMID: 10968138

Between November 1994 to May 1996, there was a total of eight ureteric injuries out of 2495 major gynaecologic operations and one ureteric injury out of 4146 caesarean sections at the Kandang Kerbau Hospital, giving the incidence to be 0.3% and 0.02% respectively. Antecedent operations were four abdominal hysterectomies, two Werthiem's hysterectomies, one laparoscopic-assisted vaginal hysterectomy and one caesarean section. All operations were performed by qualified specialists. Three patients had previous abdominal operations and five patients had procedures complicated by dense adhesions. Only one injury was detected intraoperatively and the rest presented with uretero-vaginal fistula. One presented with immediate postoperative anuria. The average time interval for diagnosis ranged between one day and twenty-three days (average 10.7 days). The commonest damage was transection of the ureter. Double J stents were used in all repairs with two cases requiring reimplantation with psoas hitch, and two cases of ureteroneocystostomies and one case of primary reanastomosis. There were no mortality in our series.
Longevity of antibody responses to a Salmonella typhi-specific outer membrane protein: interpretation of a dot enzyme immunosorbent assay in an area of high typhoid fever endemicity

Choo KE, Davis TM, Ismail A, Ong KH

Am J Trop Med Hyg, 1997 Dec;57(6):656-9.
PMID: 9430522

The objective of this study was to investigate the longevity of positive dot enzyme immunosorbent assay (dot EIA) results for IgM and IgG to a Salmonella typhi outer membrane protein in Malaysian children with enteric fever. The patients were children one month to 12 years of age with clinical evidence of typhoid fever, positive blood or stool cultures for S. typhi, and/or a positive Widal test result who were admitted over a two-year period to General Hospital (Kota Bharu, Malaysia). These patients received standard inpatient treatment for enteric fever including chloramphenicol therapy for 14 days. Dot EIA tests were performed as part of clinical and laboratory assessments on admission, at two weeks, and then at 3, 6, 9, 12, 15, 18, and 21 months postdischarge. Assessment of the longevity of positive dot EIA IgM and IgG titers was done by Kaplan-Meier analysis. In 94 evaluable patients, 28% were dot EIA IgM positive but IgG negative on admission, 50% were both IgM and IgG positive, and 22% were IgM negative and IgG positive. Mean persistence of IgM dot EIA positivity was 2.6 months (95% confidence interval = 2.0-3.1 months) and that of IgG was 5.4 months (4.5-6.3 months). There were no significant differences between the three subgroups. Thus, positive IgM and IgG results determined by dot EIA within four and seven months, respectively, following documented or suspected enteric fever in a child from an endemic area should be interpreted with caution. In other clinical situations, the dot EIA remains a rapid and reliable aid to diagnosis.
The effects of oestradiol and relaxin on extensibility and collagen organisation of the pregnant rat cervix

Cheah SH, Ng KH, Johgalingam VT, Ragavan M

J Endocrinol, 1995 Aug;146(2):331-7.
PMID: 7561646

The effects of exogenously introduced oestradiol-17 beta (E) and relaxin (RLX) on cervical extensibility and collagen organisation were tested in rats ovariectomised in late pregnancy. When the cervices were stretched in vitro by 1 mm increments, it was found that those from rats given E alone generated significantly higher tensions than those from control rats, while cervices from rats given both E and RLX had tensions similar to controls. Examination of cervical sections under the light microscope and ultra-thin sections under the electron microscope showed that the collagen fibres in the cervices from E-treated rats were highly organised, whereas those from animals given E+RLX and control animals were disorganised and dispersed. It was concluded that E decreased cervical extensibility, while RLX counteracted the effect of E to maintain a soft and easily extensible cervix.
Fulltext Ondansetron against metoclopramide/dexamethasone--a comparative study

Lim AKH, Haron MR, Yap TM

Med J Malaysia, 1994 Sep;49(3):231-8.
PMID: 7845271

This trial was carried out in Hospital Kuala Lumpur. Fifty-two patients who were scheduled to receive their first or subsequent courses of cancer chemotherapy with single dose cisplatinum containing chemotherapy regimens were evaluated. Thirty-four patients were given ondansetron in one group while 18 in the other group received metoclopramide with dexamethasone. The response to treatment was categorised as complete (0 emetic episode), major (1 or 2 emetic episodes), minor (3 to 5 emetic episodes) or failure (> 5 emetic episodes or rescue medication). Among the 52 patients, a complete or major control (0 to 2 emetic episodes) was achieved in 23/34 patients (68%) from the ondansetron group and in 3/18 patients (17%) from the metoclopramide with dexamethasone group (p < 0.002) on day 1. Similarly, the control of nausea was greater in the ondansetron group compared with the metoclopramide with dexamethasone group (p < 0.0009) on day 1. Two patients were excluded (dropped out) after day one from each of the two study groups due to excessive vomiting subsequent to cisplatinum therapy. From days 2 to 6, there was a trend in favour of ondansetron. Both treatments were well tolerated. The results of this trial show that in the prophylaxis of nausea and vomiting induced by cisplatinum containing chemotherapy, the efficacy of ondansetron is superior to that of a standard anti-emetic combination, metoclopramide with dexamethasone.
Rapid serodiagnosis of typhoid fever by dot enzyme immunoassay in an endemic area

Choo KE, Oppenheimer SJ, Ismail AB, Ong KH

Clin Infect Dis, 1994 Jul;19(1):172-6.
PMID: 7948526

A dot enzyme immunoassay (EIA) using 50-kD outer-membrane proteins (OMPs) of Salmonella typhi was compared with the Widal test for the serodiagnosis of typhoid fever in 109 febrile children admitted to a hospital in an endemic area. In the culture-positive typhoid group, the initial dot EIA was positive in 40 of 42 cases and the initial Widal test was positive in 41. In the culture-negative clinical typhoid group, both the dot EIA and the Widal test were positive in 17 of 18 cases. In the nontyphoidal fever group, the dot EIA was negative in all of 49 cases and the Widal test was negative in 44. With culture used as the gold standard, the dot EIA is as sensitive as the Widal test (95% vs. 98%), has a similar high negative predictive value (96% vs. 98%), and is more specific (75% vs. 67%). In addition, the dot EIA offers the advantages of simplicity, speed, early diagnosis, economy, and flexibility (i.e., other diagnostic tests can be conducted simultaneously).
Percutaneous transvenous mitral commissurotomy in patients with severe kyphoscoliosis

Ramasamy D, Zambahari R, Fu M, Yeh KH, Hung JS

Cathet Cardiovasc Diagn, 1993 Sep;30(1):40-4.
PMID: 8402863

Because transseptal catheterization is felt to be contraindicated in patients with severe kyphoscoliosis, there have been no reports of percutaneous transvenous mitral commissurotomy performed in such patients. This report describes percutaneous transvenous mitral commissurotomy in three patients with severe thoracic kyphoscoliosis, with special emphasis on the transseptal puncture technique. Biplane right atrial angiography and the contrast septal flush method are very useful in landmark selection for a safe transseptal puncture.
Fulltext Factors influencing pulse oximetry as compared to functional arterial saturation in multi-ethnic Singapore

Lee KH, Hui KP, Tan WC, Lim TK

Singapore Med J, 1993 Oct;34(5):385-7.
PMID: 8153680

Noninvasive oximetry provides continuous monitoring of arterial oxygen saturation and hence, early detection of hypoxia. This has proved to be a useful adjunct to patients' safety, and is considered indispensable in certain settings. However, errors may be present in the pulse oximeter estimation (SpO2) of arterial oxygen saturation (SaO2), which may be due to various parameters. We have studied a multi-ethnic population where the skin pigmentation is different, and also under different conditions comparing SpO2 with SaO2. Our results showed that SpO2 estimation of SaO2 amongst the three racial groups (Chinese, Malays, and Indians) varied significantly (ANOVA, p < 0.05). The over-estimation was more pronounced by hypoxic conditions and jaundice. Haemoglobin and systolic blood pressure did not affect the difference between SpO2 and SaO2.
Anemia in remote interior communities in Sarawak, Malaysia

Sagin DD, Ismail G, Mohamad M, Pang EK, Sya OT

Southeast Asian J Trop Med Public Health, 2002 Jun;33(2):373-7.
PMID: 12236440

A cross-sectional survey of 365 individuals, (51.9% males, 48.1% females; ages 5-85 years), from five remote interior communities in upper Rejang River basin Sarawak, Malaysia, found 24.4% were anemic. The range and mean of Hb concentration in male and female were: 7.2-17.0 mg/ml and 13.7 mg/ml and 7.9-15.7 mg/ml and 12.9 mg/ml respectively. Amongst the five tribes surveyed, the prevalence of anemia (range: 10.6-46.7%), was higher among the Penans (46.7%), Kenyahs (31.1%), Kajangs (27.8%) and Kayans (19.3%), than amongst the Ukits (10.6%). Anemia is more common among males >40 years and among adolescents and young reproductive females, as well as elderly females > 61 years old. Of the 83 anemic individuals, 6.0% and 3.6% had Trichuris trichiura or hookworm respectively; however there is no clear association with intestinal worm infection.
A proposed hierarchical fuzzy inference system for the diagnosis of arthritic diseases

Lim CK, Yew KM, Ng KH, Abdullah BJ

Australas Phys Eng Sci Med, 2002 Sep;25(3):144-50.
PMID: 12416592 DOI: 10.1007/BF03178776

Development of computer-based medical inference systems is always confronted with some difficulties. In this paper, difficulties of designing an inference system for the diagnosis of arthritic diseases are described, including variations of disease manifestations under various situations and conditions. Furthermore, the need for a huge knowledge base would result in low efficiency of the inference system. We proposed a hierarchical model of the fuzzy inference system as a possible solution. With such a model, the diagnostic process is divided into two levels. The first level of the diagnosis reduces the scope of diagnosis to be processed by the second level. This will reduce the amount of input and mapping for the whole diagnostic process. Fuzzy relational theory is the core of this system and it is used in both levels to improve the accuracy.
Hypercalcaemia in patients with newly diagnosed tuberculosis in Malaysia

Liam CK, Lim KH, Srinivas P, Poi PJ

Int J Tuberc Lung Dis, 1998 Oct;2(10):818-23.
PMID: 9783529

University Hospital, Kuala Lumpur, Malaysia.
Fulltext Stroke audit

Chen RYT, Lim JKH, Chuo AML

Med J Malaysia, 2003 Aug;58(3):330-6.
PMID: 14750371

Medical audit is vital to ensure continuous quality assurance and quality improvements. We did a retrospective study to ascertain the adequacy of clinical documentation and the factors hindering early discharge after an acute stroke in a restructured hospital. The medical records of all patients with acute stroke who died or were discharged from a restructured hospital in Singapore in January and February 1999 were reviewed retrospectively. Demographic data and the presence or absence of clinical documentation were noted. Factors hindering the discharge of patients at Day 5, Day 10 of stroke and at final discharge were noted and classified into: stroke-related, complications of stroke, medical-related and social factors. There were 101 patients in the study cohort, 55 males (54.5%) and 46 females (45.5%). The mean age was 67.9 years (SD 12.3). Documentation in Barthel scores (0%), presence of depression (0%), mental scores (1.0%), visual problems (10.0%), bladder continence (39.6%), admission functional status (37.6%) and dysphagia (52.5%) were deficient. The mean length of stay (LOS) was 13.0 (SD 14.2) days. The main factor hindering discharge at Day 5 (90.4%), Day 10 (95.2%) and at final discharge (82.1%) was stroke-related problems. Poor function (60.3%) and dysphagia (15.8%) were the 2 most common stroke-related problems hindering final discharge. Complications of stroke, medical-related problems and social reasons hindered final discharge in 10.8%, 17.8% and 2.9% of patients respectively. This audit revealed inadequacy in clinical documentation in patients with acute stroke. The main hindrance to final discharge of patients was stroke-related problems. The 2 most important stroke-related problems were poor function and dysphagia.
Fulltext The prevalence of MTHFR 677C-->T missense mutation, total plasma homocysteine levels and associated risk factors in Malay subjects

Ling KH, Rosli R, Duraisamy G, Mohd Nasir MT

Med J Malaysia, 2003 Jun;58(2):243-54.
PMID: 14569745

The missense mutation of the methylenetetrahydrofolate reductase (MTHFR) gene 677C-->T is associated with modest elevation of homocysteine levels. The bio-ecogenetics factors of total homocysteine levels (tHcy) were investigated in a cross sectional study involving 53 randomly selected healthy Malay subjects. Results indicated that the prevalence of the homozygous 677T/T was 3.8% and heterozygous 677C/T was 17.0%. The levels of tHcy was higher in subjects aged more than 50 years (n = 7, 11.53 +/- 4.45 mumol/l) and in males (10.99 +/- 3.77 mumol/l) especially smoking males (12.19 +/- 3.62 mumol/l). THcy levels were low in the 3 pregnant subjects (4.44 mumol/l, p = 0.036) who were under folate supplementation.
Single-nucleotide polymorphisms of the interleukin-18 gene promoter region in rheumatoid arthritis patients: protective effect of AA genotype

Sivalingam SP, Yoon KH, Koh DR, Fong KY

Tissue Antigens, 2003 Dec;62(6):498-504.
PMID: 14617033 DOI: 10.1046/j.1399-0039.2003.00137.x

Rheumatoid arthritis (RA) is a chronic arthritic condition that can lead to deformities and disabilities. Although numerous studies reported the association of human leukocyte antigen (HLA)-DRB1*04 and RA, other genes, e.g. cytokines genes, may contribute towards disease susceptibility. Interleukin-18 (IL-18) is a proinflammatory cytokine postulated to play a role in the acute and chronic inflammatory phases of RA. The IL-18 protein expression seems to be regulated by two single-nucleotide polymorphisms (SNPs) located at positions -607 and -137 in the promoter region of the gene. It is postulated that specific alleles may be associated with susceptibility to the development of RA. In the present study, we described the IL-18 gene promoter region genotypes and combined genotypes (-607/-137) in 106 RA patients and 273 unrelated healthy controls to evaluate the contributions of these alleles to RA predisposition in Chinese, Malays, and Indians. The genotyping were performed using sequence-specific polymerase chain reactions. Rheumatoid factors were assayed by enzyme-linked immunosorbent assay. Biodata were obtained through chart review. The controls had significantly higher frequency of AA genotype at position -607 when compared to RA patients. No significant differences were observed in the distribution of either allelic or genotypic frequencies at position -137. There was no association between the genotypes and the presence of rheumatoid factors. This study did not find evidence of a genetic susceptibility factor but demonstrated the novel finding that the AA genotype at position -607 is associated with a protective effect against development of RA in Chinese individuals. This protection may be mediated through inhibition of cyclic (Adenosine 3', 5'-cyclic monophosphate) AMP-responsive element (CRE)-binding protein by the disruption of the CRE consensus sequence.
Paroxysmal atrial fibrillation prediction method with shorter HRV sequences

Boon KH, Khalil-Hani M, Malarvili MB, Sia CW

Comput Methods Programs Biomed, 2016 Oct;134:187-96.
PMID: 27480743 DOI: 10.1016/j.cmpb.2016.07.016

This paper proposes a method that predicts the onset of paroxysmal atrial fibrillation (PAF), using heart rate variability (HRV) segments that are shorter than those applied in existing methods, while maintaining good prediction accuracy. PAF is a common cardiac arrhythmia that increases the health risk of a patient, and the development of an accurate predictor of the onset of PAF is clinical important because it increases the possibility to stabilize (electrically) and prevent the onset of atrial arrhythmias with different pacing techniques. We investigate the effect of HRV features extracted from different lengths of HRV segments prior to PAF onset with the proposed PAF prediction method. The pre-processing stage of the predictor includes QRS detection, HRV quantification and ectopic beat correction. Time-domain, frequency-domain, non-linear and bispectrum features are then extracted from the quantified HRV. In the feature selection, the HRV feature set and classifier parameters are optimized simultaneously using an optimization procedure based on genetic algorithm (GA). Both full feature set and statistically significant feature subset are optimized by GA respectively. For the statistically significant feature subset, Mann-Whitney U test is used to filter non-statistical significance features that cannot pass the statistical test at 20% significant level. The final stage of our predictor is the classifier that is based on support vector machine (SVM). A 10-fold cross-validation is applied in performance evaluation, and the proposed method achieves 79.3% prediction accuracy using 15-minutes HRV segment. This accuracy is comparable to that achieved by existing methods that use 30-minutes HRV segments, most of which achieves accuracy of around 80%. More importantly, our method significantly outperforms those that applied segments shorter than 30 minutes.
Automated otolith image classification with multiple views: an evaluation on Sciaenidae

Wong JY, Chu C, Chong VC, Dhillon SK, Loh KH

J Fish Biol, 2016 Aug;89(2):1324-44.
PMID: 27364089 DOI: 10.1111/jfb.13039

Combined multiple 2D views (proximal, anterior and ventral aspects) of the sagittal otolith are proposed here as a method to capture shape information for fish classification. Classification performance of single view compared with combined 2D views show improved classification accuracy of the latter, for nine species of Sciaenidae. The effects of shape description methods (shape indices, Procrustes analysis and elliptical Fourier analysis) on classification performance were evaluated. Procrustes analysis and elliptical Fourier analysis perform better than shape indices when single view is considered, but all perform equally well with combined views. A generic content-based image retrieval (CBIR) system that ranks dissimilarity (Procrustes distance) of otolith images was built to search query images without the need for detailed information of side (left or right), aspect (proximal or distal) and direction (positive or negative) of the otolith. Methods for the development of this automated classification system are discussed.
Fulltext Laparoscopic sterilization with fallope rings - a Malaysian experience

Abdul Rahman A, Sinnathuray TA, Sivanesaratnam V, Ng KH

Med J Malaysia, 1981 Jun;36(2):92-9.
PMID: 6211595

The early Malaysian experience of laparoscopic sterilisation with the Fallope tubal rings, as undertaken at the Obstetrical and Gynaecological Unit of the University Hospital, University of Malaya in Kuala Lumpur, Malaysia is reported in a study of 291 consecutive females that had had the procedure undertaken during the one year period, May 1975 to April 1976. Of the 291 cases, 247 women were sterilised in the "interval" period, 43 after "menstrual regulation" procedure and one after a spontaneous abortion. General anaesthesia was used in all except one case. The salient socio-demographic, contraceptive and reproductive characteristics of study cases are presented and discussed. The technical problems, the early complications and morbidity encountered in this study are presented and discussed in the light of other similar studies, and in relation to sterilisation by laparoscopic tubal electrocoagulation. The overall impression is that laparoscopic sterilisation with the Fallope tubal rings is preferred to that by tubal electrocoagulation, in view of the possible inadvertent serious electrical burns of other structures during the use of the latter procedure.
Genetic markers of an aboriginal Taiwanese population

Chen KH, Cann H, Chen TC, Van West B, Cavalli-Sforza L

Am J Phys Anthropol, 1985 Mar;66(3):327-37.
PMID: 3857010

A group of Taiwan aborigines, the Toroko, was typed for 21 classical genetic loci. This is part of an ongoing program aimed at a comprehensive study of Taiwan aborigines. In this first paper a short summary of historical, archeological, and anthropological data in the literature is made, and results of the present survey are compared with older results from other aborigine tribes. An analysis of other neighboring populations from southeast Asia has also been carried out in order to give a preliminary answer to the question of origin of Taiwanese aborigines. Fifteen populations were studied for 13 loci by tree analysis, principal components, and isolation by distance. Tree analysis and principal component analysis gave results in fairly good agreement and indicate three major population clusters: a northeast cluster (Ainu, Korea, Japan, and Ryukyu); a southeast cluster (south China, Thailand, Vietnam, Philippines, Taiwan, and Toroko); and a third cluster including Malaya and Borneo. The positions of Polynesia, Micronesia, and Melanesia are somewhat peripheral. Analysis of the tree shows some potential cases of convergence, perhaps owing to admixture, and of divergence. The analysis of isolation by distance shows that geographic propinquity is a reasonably good predictor of general similarity in this area.

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