Displaying publications 1 - 20 of 45 in total

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  1. Azila N, Ong KK
    Int. J. Biochem., 1989;21(10):1157-9.
    PMID: 2555229
    1. The activity of cAMP phosphodiesterase (PDE) was studied in a 10,000 g particulate fraction prepared from rat brain. 2. Phospholipase C such as sphingomyelin choline phosphodiesterase (SMase), phosphatidylinositol phosphodiesterase (PIase) and phosphatidylcholine phosphohydrolase (PCase) were used to deplete phospholipid(s) from the particulate fraction and their effects on PDE activity were investigated. 3. Treatment with SMase or PIase did not affect PDE activity whereas treatment with PCase resulted in inhibition. 4. It was also found that the PCase used not only hydrolyzed phosphatidylcholine but also other phospholipids such as phosphatidylethanolamine, phosphatidylserine and sphingomyelin.
  2. Wang SY, Ong KO
    Med J Malaysia, 2015 Feb;70(1):33-5.
    PMID: 26032527
    Pedunculated subcutaneous lipoma in the popliteal fossa extending through the superficial fascia causing chronic irritant dermatitis of the adjacent skin with "psoriatic-like" plaque. To the author's knowledge, no similar case has been reported in the literature.
  3. Wong KT, Ong KC
    Patholog Res Int, 2011;2011:567248.
    PMID: 21961078 DOI: 10.4061/2011/567248
    Zoonoses as causes of human infections have been increasingly reported, and many of these are viruses that cause central nervous system infections. This paper focuses on the henipaviruses (family Paramyxoviridae, genus henipavirus) that have recently emerged to cause severe encephalitis and systemic infection in humans and animals in the Asia-Pacific region. The pathological features in the human infections comprise vasculopathy (vasculitis, endothelial multinucleated syncytia, thrombosis, etc.) and parenchymal cell infection in the central nervous system, lung, kidney, and other major organs. Most animals naturally or experimentally infected show more or less similar features confirming the dual pathogenetic mechanism of vasculopathy-associated microinfarction and direct extravascular parenchymal cell infection as causes of tissue injury. The most promising animal models include the hamster, ferret, squirrel monkey, and African green monkey. With increasing evidence of infection in the natural hosts, the pteropid bats and, hence, probable future outbreaks in many more countries, a greater awareness of henipavirus infection in both humans and animals is imperative.
  4. Siang Soh C, Meng Ong K, Raveendran P
    Conf Proc IEEE Eng Med Biol Soc, 2007 2 7;2005:1178-81.
    PMID: 17282402
    Genetic algorithm is used to perform variable selection to determine the ranges of wavelengths in NIR spectral data suitable to be used as predictors in multivariate calibration model via partial least squares. The NIR spectral data consists of three components of active substances, namely human serum albumin (HSA), γ-globulin and glucose. The wavelength selection is able to improve the calibration model by selecting the wavelengths that contains information or correlated with the concentration of substances, while others non-chosen wavelengths, which contribute no information or contain noises, are excluded from the calibration model.
  5. Zubaidah NH, Azuawarie A, Ong KW, Gee T
    Med J Malaysia, 2015 Feb;70(1):57-8.
    PMID: 26032535 MyJurnal
    Traumatic diaphragmatic hernia is a well known complication of blunt trauma to the abdomen and thorax. In the acute setting, laparotomy is mandatory. In this current era, this condition can be managed with minimally invasive surgery. We hereby report a case of delayed large left diaphragmatic hernia that was repaired with a combination of laparoscopic and thoracoscopic approach.
  6. Razak MA, Ong KP, Hyzan Y
    Med J Malaysia, 1998 Sep;53 Suppl A:12-21.
    PMID: 10968178
    A retrospective study was conducted to assess the surgical outcomes of degenerative lumbar spinal stenosis. Twenty-five patients treated with decompressive surgery in Hospital Kuala Lumpur between January 1992 and August 1996 were reviewed. There were seven males and eighteen females. The average age was 51 years old (range 33 to 64 years old). The diagnosis of degenerative spinal stenosis was made based on the clinical features and was confirmed by radiographic findings. Ninety two percent of the patients had moderate to severe symptoms preoperatively. The types of surgery consisted of laminectomy (n = 15), laminotomy (n = 10), and laminoplasty (n = 1). The surgical outcomes were assessed based on patients' own assessment of symptoms relieved and functional returned to daily activities at least six months after the surgery. The average follow-up period was fifteen months (range 6 months to 42 months). Of these twenty-five patients, 4 (16%) claimed to have excellent results, 11 (44%) had good results, 8 (32%) reported fair, and 2 (8%) judged their surgical treatment as poor with little or no use. There was no anaesthetic, cardiovascular, or thromboembolic complications seen in this study. Four patients had recurrent claudication, one demonstrated localised arachnoiditis, and two had lumbar instability which were not documented preoperatively. One patient had L4 nerve root avulsion with dura torn and another patient had superficial wound infection. We concluded in this study that decompressive surgery offers satisfactory results in patients with moderate to severe degenerative spinal stenosis in short term follow-up.
  7. Rohani MY, Hasnidah D, Ong KH
    Malays J Pathol, 1998 Jun;20(1):31-3.
    PMID: 10879261
    A chromatographic immunoassay cholera antigen detection kit, the Cholera Spot test, was evaluated. The test was found to be specific with a sensitivity of 10(6) cfu/ml for the direct detection of V. cholerae in simulated stool specimens and 10 cfu/ml in simulated cotton-tipped swab specimens after overnight incubation in alkaline peptone water. This enables early recognition of cholera cases and their contacts so that prevention and control measures can be promptly instituted.
  8. Ong KK, Khor HT, Tan DT
    Anal Biochem, 1991 Aug 01;196(2):211-4.
    PMID: 1776669
    A rapid, easy, and sensitive method is described in this paper for the assay of 3-hydroxy-3-methylglutaryl CoA (HMG CoA) reductase, a key enzyme in cholesterol biosynthesis. [14C]HMG CoA was used as the substrate and the product formed, i.e., [14C]mevalonate, was allowed to be converted to its lactone form (mevalonolactone) in the presence of HCl. The reaction mixture was applied to a column containing an anionic exchanger. The column was made up of QAE-Sephadex (A25, formate form) packed to a height of 4 cm in Pasteur pipets. Under these conditions, mevalonolactone was not retained by the column and was eluted with ammonium formate solution while HMG CoA, being negatively charged, was retained by the gel and eluted by HCl above 0.05 M. Determination of the amount of radioactivity in mevalonolactone was then used to quantitate the activity of HMG CoA reductase. This assay has been successfully used for determining the activity of this enzyme in a microsomal fraction prepared from the liver of the rat.
  9. Azila N, Kuppusamy UR, Ong KK
    Biochem. Int., 1989 Nov;19(5):1077-85.
    PMID: 2561441
    Cyclic AMP phosphodiesterase (PDE) activity was assayed in the plasma membrane, mitochondrial and microsomal fractions of rat brain. The specific activity of the enzyme was highest in the plasma membrane fraction followed by mitochondrial and then the microsomal fraction. Phosphodiesterase activity of all three fractions was reduced after pretreatment with lecithinase C (PCase) from Clostridium perfringens but less markedly affected by the pretreatment with sphingomyelinase (SMase) from human placenta. The PDE activity of the plasma membrane fraction was more sensitive to PCase treatment compared with the other two particulate fractions, which showed only a slight loss of activity. Temperature seemed to affect PDE activity of the plasma membrane. The enzyme was quite stable at 30 degrees C but its activity dropped by approximately 46% at 37 degrees C after 90 min of incubation. Pretreatment of the plasma membrane at 30 degrees C with PCase at a concentration of more than 5 U caused a marked loss of PDE activity and the decrease in activity reached a plateau at concentrations above 10 U.
  10. Thuraikumar K, Wan KL, Ong KL, Lim SW
    Malays Orthop J, 2020 Jul;14(2):141-144.
    PMID: 32983391 DOI: 10.5704/MOJ.2007.024
    Gouty arthritis commonly affects peripheral joints and is associated with hyperuricaemia. Spinal manifestations of gouty arthritis are not common, and majority of published articles worldwide were case reports. This is a case report of spinal gouty arthritis that presented with spinal vertebrae destruction and cauda equina syndrome. The magnetic resonance imaging (MRI) showed destruction of L5/S1end plates with cystic collection mimicking infective changes. The tissue histological examination confirmed presence of urate crystal needles that displayed negative double refraction on light microscopy. Spinal gouty arthritis is part of the differential diagnoses in gouty arthritis patients.
  11. Goh KL, Parasakthi N, Ong KK
    Am J Gastroenterol, 1996 Feb;91(2):268-70.
    PMID: 8607491
    OBJECTIVES:
    The aims of the study were, first, to determine the prevalence of Helicobacter pylori (HP) among endoscopy personnel and a group of non-endoscopy volunteers and, second, to evaluate the usefulness of two noninvasive tests of diagnosis: serology and the urea breath test.

    METHODS:
    The two noninvasive methods of HP diagnosis, serology and 14C-urea breath test (UBT), were used in a cross-sectional survey of endoscopists, nurse-assistants, and non-endoscopy personnel.

    RESULTS:
    One hundred and thirty-five volunteers were recruited for the study. In 116, results of the two tests were in agreement (kappa = 0.645). Further analysis was based on the results of the UBT. Endoscopy personnel (endoscopists and nurse-assistants) as a group had a significantly higher incidence of HP than did controls (32.9% vs. 11.3%; p = 0.004). The two groups were comparable with regard to mean age, sex, ethnic distribution, and social class.

    CONCLUSIONS:
    HP infection is more prevalent among endoscopy personnel. Both diagnostic tests (serology and UBT) were convenient and relatively simple to perform, and results gave a high level of agreement.
  12. Ong K, Ng KW, Haw SC
    F1000Res, 2021;10:1079.
    PMID: 38550618 DOI: 10.12688/f1000research.73240.1
    In recent years, Recommender System (RS) research work has covered a wide variety of Artificial Intelligence techniques, ranging from traditional Matrix Factorization (MF) to complex Deep Neural Networks (DNN). Traditional Collaborative Filtering (CF) recommendation methods such as MF, have limited learning capabilities as it only considers the linear combination between user and item vectors. For learning non-linear relationships, methods like Neural Collaborative Filtering (NCF) incorporate DNN into CF methods. Though, CF methods still suffer from cold start and data sparsity. This paper proposes an improved hybrid-based RS, namely Neural Matrix Factorization++ (NeuMF++), for effectively learning user and item features to improve recommendation accuracy and alleviate cold start and data sparsity. NeuMF++ is proposed by incorporating effective latent representation into NeuMF via Stacked Denoising Autoencoders (SDAE). NeuMF++ can also be seen as the fusion of GMF++ and MLP++. NeuMF is an NCF framework which associates with GMF (Generalized Matrix Factorization) and MLP (Multilayer Perceptrons). NeuMF achieves state-of-the-art results due to the integration of GMF linearity and MLP non-linearity. Concurrently, incorporating latent representations has shown tremendous improvement in GMF and MLP, which result in GMF++ and MLP++. Latent representation obtained through the SDAEs' latent space allows NeuMF++ to effectively learn user and item features, significantly enhancing its learning capability. However, sharing feature extractions among GMF++ and MLP++ in NeuMF++ might hinder its performance. Hence, allowing GMF++ and MLP++ to learn separate features provides more flexibility and greatly improves its performance. Experiments performed on a real-world dataset have demonstrated that NeuMF++ achieves an outstanding result of a test root-mean-square error of 0.8681. In future work, we can extend NeuMF++ by introducing other auxiliary information like text or images. Different neural network building blocks can also be integrated into NeuMF++ to form a more robust recommendation model.
  13. Madhavan HN, Ong KH, Anuar K
    PMID: 3024324
    During 1984-1985, a total of 838 sera obtained from individuals of different age groups, mostly blood donors and those whose sera were received for VDRL tests and other serological investigations. The sera were titrated for complement fixing antibodies against cytomegalovirus (Ad169 strain). Three hundred and fifty two (41%) out of 838 sera showed significant antibody titre. The incidence of this virus infection varied form 26% in the age group of 11-20 years to 59% of those above 50 years of age. Geometric mean titre (GMT) was highest (22) in age groups of 11-20 years and those over 50 years indicating active viral infection in these two age groups. GMT was also significantly higher in females in all age groups except in the age group of 21-30 years and those above 50 years, indicating that active viral infection is more common in females.
  14. Jegathesan M, Fan YH, Ong KJ
    PMID: 1241163
    Seroreactivity to syphilis is high among Malaysian blood donors and expectant mothers indicating a high degree of treponemal infection. Further epidemiological studies are required to ascertain what proportion of these could be syphilis and what porportion yaws. Blood donors hava a higher reactivity rate than expectant mothers, the reasons probably being soical. The titres obtained in the VDRL test appear to have a relation to FTA-ABS reactivity although this is not to say treponematosis can be excluded on the basis of low titre VDRL results.
  15. Chang KW, Alsagoff S, Ong KT, Sim PH
    Med J Malaysia, 1998 Dec;53(4):428-31.
    PMID: 10971989
    An open comparative randomised study comparing the performance of hydrocolloid dressings (DuoDERM CGF) to saline gauze dressings in the treatment of pressure ulcers was done to evaluate the overall dressing performance, wound healing and cost effectiveness. Thirty-four subjects were enrolled at the University Hospital, Kuala Lumpur over a 643 days period. Inclusion criteria were Stage II or III pressure ulcers, at least 18 years of age and written informed consent. Only one pressure ulcer per subject was enrolled in the study. Patients with infected pressure ulcers, diabetes mellitus, an immuno-compromised status and known sensitivity to the study dressings were excluded. Subjects who met the enrollment criteria were randomised to one of the two dressing regimes. They were expected to participate in the study for a maximum of eight weeks or until the pressure ulcer healed, which ever occurred first. Overall subject age averaged 58 years and the mean duration of pressure ulcer existence was about 1 month. Twenty-one of the thirty-four ulcers enrolled were stage II and thirteen were stage III. The majority of the ulcers (88%) were located in the sacral area and seventeen subjects (50%) were incontinent. In the evaluation of dressing performance in terms of adherence to wound bed, exudate handling ability, overall comfort and pain during dressing removal; all favoured the hydrocolloid dressing by a statistically significant margin (p < 0.001). Subjects assigned the hydrocolloid dressing experienced a mean 34% reduction from their baseline surface area measurement compared to a mean 9% increase by subjects assigned gauze dressings. This was not statistically significant (p = 0.2318). In cost evaluation of the study products, there was no statistical significance in the total cost of wound management per subject. When only labour time and cost was evaluated, there was a statistically significant advantage towards hydrocolloid dressings.
  16. Ong KK, Fakhru'l-Razi A, Baharin BS, Hassan MA
    PMID: 10595436
    The application of membrane separation in palm oil refining process has potential for energy and cost savings. The conventional refining of crude palm oil results in loss of oil and a contaminated effluent. Degumming of crude palm oil by membrane technology is conducted in this study. The objective of this research is to study the feasibility of membrane filtration for the removal of phospholipids in the degumming of crude palm oil, including analyses of phosphorus content, carotene content free fatty acids (as palmitic acid), colour and volatile matter. A PCI membrane module was used which was equipped with polyethersulfone membranes having a molecular weight cut off of 9,000 (type ES209). In this study, phosphorus content was the most important parameter monitored. The membrane effectively removed phospholipids resulting in a permeate with a phosphorus content of less than 0.3 ppm The percentage removal of phosphorus was 96.4% and was considered as a good removal. Lovibond colour was reduced from 27R 50Y to 20R 30Y. The percentage removal of carotene was 15.8%. The removal of colour was considered good but the removal of carotene was considered insignificant by the membrane. Free fatty acids and volatile matter were not removed. Typical of membrane operations, the permeate flux decreased with time and must be improved in order to be adopted on an industrial scale. Membrane technology was found to have good potential in crude palm oil degumming. However, an appropriate method has to be developed to clean the membranes for reuse.
  17. Goh KL, Parasakthi N, Peh SC, Ong KK
    Med J Malaysia, 1995 Sep;50(3):208-11.
    PMID: 8926896
    Sixty-three breath samples were collected from patients who underwent a 14C-urea breath test. Following ingestion of a radiolabelled 14C-labelled urea solution, breath samples containing 14C-labelled carbon dioxide were trapped in a solution containing hyamine hydroxide. Samples were then counted in a liquid scintillation counter. Breath samples were collected at 2, 15, 20, 25 and 30 minutes following ingestion of the urea solution. The presence or absence of Helicobacter pylori (HP) infection was determined on the basis of endoscopic biopsy tests which included culture, histological examination, rapid urease test and a gram stain of a fresh tissue smear. Thirty-two HP positive and 31 HP negative samples were collected. The mean counts at 15, 20, 12 and 30 minutes time points were: 4413, 4458, 4109 and 3795 dpm respectively for the positive samples and 1275, 877, 690 and 565 dpm respectively for the negative samples. Based on a cutoff value (mean of the negative samples + 3 standard deviations) for every time point, HP positive and negative samples could be clearly differentiated giving a sensitivity and specificity of 100%. The 14C-urea breath test is a reliable and convenient diagnostic test for H. pylori.
  18. Kong NC, Nasruruddin BA, Murad S, Ong KJ, Sukumaran KD
    Lupus, 1994 Oct;3(5):393-5.
    PMID: 7841992 DOI: 10.1177/096120339400300505
    Many studies have shown an association between human leucocyte antigens (HLA) and systemic lupus erythematosus (SLE) in the various study populations. Although SLE is not an uncommon disease in the Malaysian Archipelago, and appears to affect all three major racial groups equally (i.e. Southern Chinese, Malays and Southern Indians), very little information is available on the HLA profiles in the two latter groups. In phase I of our study of the HLA profiles in Malaysian SLE patients, the HLA phenotypes (class I: A, B, C; Class II: DR, DQ) of Malay patients with confirmed SLE and 91 normal Malay controls were determined using the microcytotoxicity assay. The strong association between DR (RR 3.28, P = 0.008) concurs with that reported among Chinese and Japanese populations. Moderate to strong associations with HLA-B 7 (RR 4.99, P = 0.02) and Cw 7 (RR 2.94, P = 0.003) were also found. We believe this is the first report of the association of HLA and SLE in the Malay population.
  19. 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).
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