Displaying publications 61 - 80 of 140 in total

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  1. Chook JB, Ngeow YF, Khang TF, Ng KP, Tiang YP, Mohamed R
    J Med Virol, 2013 Mar;85(3):419-24.
    PMID: 23297244 DOI: 10.1002/jmv.23500
    Infection with the hepatitis B virus (HBV) may lead to an acute or chronic infection. It is generally accepted that the clinical outcome of infection depends on the balance between host immunity and viral survival strategies. In order to persist, the virus needs to have a high rate of replication and some immune-escape capabilities. Hence, HBVs lacking these properties are likely to be eliminated more rapidly by the host, leading to a lower rate of chronicity. To test this hypothesis, 177 HBV genomes from acute non-fulminant cases and 1,149 from chronic cases were retrieved from GenBank for comparative analysis. Selection of candidate nucleotides associated with the disease state was done using random guess cut-off and the Bonferroni correction. Five significant nucleotides were detected using this filtering step. Their predictive values were assessed using the support vector machine classification with five-fold cross-validation. The average prediction accuracy was 61% ± 1%, with a sensitivity of 24% ± 1%, specificity of 98% ± 1%, positive predictive value of 92% ± 4% and negative predictive value of 56% ± 1%. BCP/X, enhancer I and surface/polymerase variants were found to be associated almost exclusively with acute hepatitis. These HBV variants are novel potential markers for non-progression to chronic hepatitis.
  2. Looi CY, D' Silva EC, Seow HF, Rosli R, Ng KP, Chong PP
    FEMS Microbiol Lett, 2005 Aug 15;249(2):283-9.
    PMID: 16006060
    The aims of our research were to investigate the gene expression of the multidrug efflux transporter, CDR1 and the major drug facilitator superfamily transporter, MDR1 gene in azole drug-resistant Candida albicans and Candida glabrata clinical isolates recovered from vaginitis patients; and to identify hotspot mutations that may be present in the C. albicans CaCDR1 gene that could be associated with drug-resistance. The relative expression of the CDR1 and MDR1 transcripts in ketoconazole and clotrimazole-resistant isolates and drug-susceptible ATCC strains were determined by semi-quantitative reverse transcription-polymerase chain reaction. Expression of CaCDR1 transcript was upregulated to varying extents in all three azole-resistant C. albicans isolates studied (1.6-, 3.7- and 3.9-fold) and all three C. glabrata isolates tested (at 1.9-, 2.3- and 2.7-fold). The overexpression level of CaCDR1 in the isolates correlated with the degree of resistance as reflected by the minimum inhibitory concentration (MIC) of the drugs. The messenger RNA for another efflux pump, MDR1, was also overexpressed in one of the azole-resistant C. albicans isolates that overexpressed CDR1. This finding suggests that drug-resistance may involve synergy between energy-dependent drug efflux pumps CDR1p and MDR1p in some but not all isolates. Interestingly, DNA sequence analysis of the promoter region of the CaCDR1 gene revealed several point mutations in the resistant clinical isolates compared to the susceptible isolates at 39, 49 and 151 nucleotides upstream from the ATG start codon. This finding provides new information on point mutations in the promoter region which may be responsible for the overexpression of CDR1 in drug-resistant isolates.
  3. Gan GG, Kamarulzaman A, Goh KY, Ng KP, Na SL, Soo-Hoo TS
    Med J Malaysia, 2002 Mar;57(1):118-22.
    PMID: 14569730
    We report a case of an invasive infection with non-sporulating Chrysosporium species in a patient who was treated with chemotherapy for relapsed acute lymphoblastic leukemia. This patient presented with a persistent lobar pneumonia, skin lesions, and possible involvement of the central nervous system. The patient responded to treatment with amphotericin B and oral itraconazole.
  4. Ng KP, Madasamy M, Saw TL, Baki A, He J, Soo-Hoo TS
    Mycopathologia, 1999 10 26;144(3):135-40.
    PMID: 10531679
    The distribution of Candida species was examined using 1114 yeasts isolated from various clinical specimens. The isolates were identified by germ tube test, hyphal/pseudohyphae and chlamydoconidia production and carbohydrate assimilation test using ten carbohydrates (glucose, sucrose, trehalose, cellobiose, arabinose, galactose, mannitol, raffinose, lactose and maltose). Among the 1114 isolates studied, 9 species of Candida were identified and the relative frequency of isolation was C. albicans (44.2%), C. parapsilosis (26.0%), C. tropicalis (17.7%), C. glabrata (9.6%), C. krusei (1.2%), C. rugosa (0.6%), C. guilliermondii (0.2%), C. lusitaniae (0.08%) and C. kefyr (0.08%). Non-C. albicans was the most common Candida species isolated from blood, respiratory system, urine and skin. The isolate from vaginal swabs was predominantly C. albicans. 82.2% of C. glabrata and 64.2% of C. krusei isolated in this study were from vaginal swabs.
  5. Ng KP, Saw TL, Wong NW, Goh KL, Chuah SY, Nagaratnam M
    Med J Malaysia, 1995 Dec;50(4):302-5.
    PMID: 8668047
    Anti-HCV antibody was detected in 1.9% of the blood donors in University Hospital. Among the risk groups, 33.3% of the patients with post-transfusion hepatitis were tested positive for anti-HCV antibody. The anti-HCV antibody was detected in 30% of the IDU. Haemodialysis patients, patients with acute and chronic hepatitis and patients with liver cirrhosis appeared to have increased risk of Hepatitis C virus infection. The results indicate that the frequency of HCV infection increases with the exposure to blood or blood products.
  6. Ng KP, Soo-Hoo TS, Na SL, Gan GG, Sangkar JV, Teh AKH
    Med J Malaysia, 2003 Oct;58(4):608-12.
    PMID: 15190640
    Scopulariopsis brevicaulis is a soil fungus normally associated with onychomycosis. It causes subcutaneous infection in immunocompromised patients and is rarely isolated from blood. A case of systemic Scopulariopsis brevicaulis infection was reported in a patient with acute myeloid leukemia. The patient developed persistent fever that did not respond to wide spectrum antibiotics and amphotericin B. Scopulariopsis brevicaulis was the only pathogen isolated from blood cultures. The fever subsided with itraconazole and there was no recurrence of fungal infection with prolonged maintenance of oral itraconazole.
  7. Siar CH, Ng KH, Rasool S, Ram S, Abdul Jalil A, Ng KP
    J Oral Sci, 2003 Sep;45(3):161-4.
    PMID: 14650581
    Though oral candidosis is an opportunistic fungal infection that commonly affects immunocompromised patients, little is known of its occurrence as a complication of Non-Hodgkin's lymphoma. This paper reports a case of oral candidosis in a 20-year-old Indonesian woman with this lymphoproliferative disease. She presented with acute pseudomembranous candidosis on the dorsum and lateral borders of the tongue, bilateral angular cheilitis and cheilocandidosis. The latter is a rare clinical variant of oral candidosis, and the lesions affecting the vermilion borders presented as an admixture of superficial erosions, ulcers and white plaques. Clinical findings were confirmed with oral smears and swabs that demonstrated the presence of hyphae, pseudohyphae and blastospores, and colonies identified as Candida albicans. A culture from a saline rinse was also positive for multiple candidal colonies. Lip and oral lesions were managed with Nystatin. The lesions regressed with subsequent crusting on the lips, and overall reduction in oral thrush. As Non-Hodgkin's lymphoma is a neoplastic disease that produces a chronic immunosuppressive state, management of its oral complications, including those due to oral candidosis, is considered a long-term indication.
  8. Tumin M, Rasiah R, Noh A, Satar NM, Chong CS, Lim SK, et al.
    Clin Transplant, 2014 Apr;28(4):423-7.
    PMID: 24617562 DOI: 10.1111/ctr.12334
    A sample of Malaysians in the Klang Valley indicating their decision on becoming unrelated living kidney donors was surveyed regarding huge amounts of financial incentives to be rewarded to them. From the 1310 respondents, 72.1% said "no" on becoming a living donor. The reason "I don't think humans can live with only one kidney" scored the highest (35.6%), and from the 27.9% of the respondents who are willing to donate their organ with the right financial incentive, most of the respondents picked the reasons "I want to do something noble in life" (50%), and monetary reason scored the lowest (6.2%), indicating that financial incentive is not a major reason guiding individuals' decision on becoming living donors. We suggest that the government should put priority at targeting public education to raise the understanding on the risk, safety and the quality of life of donation and transplantation, and improving the public trust on the donation and the surgical methods to carry out transplantation.
  9. Tumin M, Noh A, Chong CS, Lim SK, Abdullah N, Ng KP
    Clin Transplant, 2013 May-Jun;27(3):E316-9.
    PMID: 23600843 DOI: 10.1111/ctr.12132
    Malaysians indicating that they did not intend to become organ donors upon their death were surveyed regarding interest in non-fungible financial incentives to be granted to surviving family members. Among the 730 (56% of the total sample of 1311) indicating unwillingness to be donors, 29.6% (216/730) subsequently indicated that they would be willing donors if the government introduced policies that, upon their death, "rewarded your (their) family with incentives for your (their) deeds." Among the 69% (504/730) who insisted that they would not become organ donor even with incentive, nearly 80% (404/501) of them were able to identify relevant incentives they thought should be provided by the state to those who make organ donations upon death. The majority of both groups preferred the state provide medical benefits to a surviving family member, suggesting this may be an attractive policy option for the state to raise the deceased organ donation pool.
  10. Lim CS, Wong WF, Rosli R, Ng KP, Seow HF, Chong PP
    J Basic Microbiol, 2009 Dec;49(6):579-83.
    PMID: 19810039 DOI: 10.1002/jobm.200900035
    Candida albicans is capable of undergoing yeast-hypha transition to attain pathogenicity in humans. In this study, we investigated the differential expression of CaSIR2 via quantitative real-time PCR (qPCR), during yeast-hypha transition with and without the presence of 2-dodecanol. SIR2 transcript levels were found to be significantly enhanced after hyphal induction as compared to the yeast form. This study found that 2-dodecanol is able to inhibit hyphal development and block SIR2 up-regulation, even in hyphal-inducing growth conditions. We suggest that SIR2 may be involved in Candida albicans quorum-sensing and serum-induced yeast-hyphae transition via the Ras1-cAMP-Efg1 signalling cascade.
  11. Ng KP, Kuan CS, Kaur H, Na SL, Atiya N, Velayuthan RD
    Trop Med Int Health, 2015 Nov;20(11):1447-1453.
    PMID: 26216479 DOI: 10.1111/tmi.12577
    To describe a prospective laboratory-based surveillance of Candida species that were collected from different anatomical sites of patients admitted to the University of Malaya Medical Centre, Malaysia, from the year 2000 to 2013.
  12. Lo SG, Wong SF, Mak JW, Choo KK, Ng KP
    Med Mycol, 2020 Apr 01;58(3):333-340.
    PMID: 31309220 DOI: 10.1093/mmy/myz061
    Cladosporium is one of the most abundant spore. Fungi of this genus can cause respiratory allergy and intrabronchial lesion. We studied the differential expression of host genes after the interaction of Cladosporium sphaerospermum conidia with Human Bronchial Epithelial Cells (BEAS-2B) and Human Pulmonary Alveolar Epithelial Cells (HPAEpiC). C. sphaerospermum conidia were harvested and co-cultured with BEAS-2B cells or HPAEpiC cells for 48 hours respectively. This culture duration was chosen as it was associated with high germination rate. RNA was extracted from two biological replicates per treatment. RNA of BEAS-2B cells was used to assess changes in gene expression using AffymetrixGeneChip® Human Transcriptome Array 2.0. After co-culture with Cladosporium spores, 68 individual genes were found differentially expressed (P ≤ 0.05) and up-regulated ≥ 1.5 folds while 75 genes were found differentially expressed at ≤ -1.5 folds compared with controls. Reverse transcription and qPCR were performed on the RNA collected from both BEAS-2B cells and HPAEpiC cells to validate the microarray results with 7 genes. Based on the findings, infected pulmonary epithelial cells exhibited an increase in cell death-related genes and genes associated with innate immunity.
  13. Tee KK, Saw TL, Pon CK, Kamarulzaman A, Ng KP
    AIDS Res Hum Retroviruses, 2005 Dec;21(12):1046-50.
    PMID: 16379608
    Earlier studies in the 1990s indicate that human immunodeficiency virus type 1 (HIV-1) subtype B has been the predominant subtype among injecting drug users (IDUs) in Malaysia. More recent studies performed between 2003 and 2004, however, show a high prevalence of unique CRF01_AE/B intersubtype recombinants among IDUs. To determine the subtype distribution among IDUs in Kuala Lumpur prior to the emergence of CRF01_AE/B intersubtype recombinants, the gag-pol or the reverse transcriptase gene was sequenced from IDUs who were diagnosed as HIV positive between 1993 and 2002. Subtype B was present at 50.0% followed by CRF01_AE/B recombinant at 41.7%, with more CRF01_AE/B recombinants detected between 2000 and 2002. All CRF01_AE/B recombinants shared similar recombination patterns. Interestingly, we found that this potential new candidate of circulating recombinant form (CRF) could have emerged as early as the mid-1990s. The results showed evidence of changing HIV-1 molecular epidemiology toward the predominance of CRF01_AE/B intersubtype recombinants among IDUs in Kuala Lumpur.
  14. Lau KA, Wang B, Kamarulzaman A, Ng KP, Saksena NK
    AIDS Res Hum Retroviruses, 2007 Sep;23(9):1139-45.
    PMID: 17919110
    A new HIV-1 circulating recombinant form (CRF), CRF33_01B, has been identified in Malaysia. Concurrently we found a unique recombinant form (URF), that is, the HIV-1 isolate 06MYKLD46, in Kuala Lumpur, Malaysia. It is composed of B or a Thai variant of the B subtype (B') and CRF01_AE. Here, we determined the near full-length genome of the isolate 06MYKLD46 and performed detailed phylogenetic and bootscanning analyses to characterize its mosaic composition and to further confirm the subtype assignments. Although the majority of the 06MYKLD46 genome is CRF01_AE, we found three short fragments of B or B' subtype inserted along the genome. These B or B' subtype regions were 716 and 335 bp, respectively, in the protease-reverse transcriptase (PR-RT) region, similar to those found in CRF33_01B, as well as an extra 590 bp in the env gene region. Thus we suggest that 06MYKLD46 is a possible second-generation HIV-1 recombinant derived from CRF33_01B.
  15. Ngeow YF, Wong YL, Tan JL, Ong CS, Ng KP, Choo SW
    J Bacteriol, 2012 Dec;194(23):6662.
    PMID: 23144407 DOI: 10.1128/JB.01846-12
    Mycobacterium abscessus is an environmental bacterium with increasing clinical relevance. Here, we report the annotated whole-genome sequence of M. abscessus strain M152.
  16. Ngeow YF, Wee WY, Wong YL, Tan JL, Ongi CS, Ng KP, et al.
    J Bacteriol, 2012 Nov;194(21):6002-3.
    PMID: 23045507 DOI: 10.1128/JB.01455-12
    Mycobacterium abscessus is a ubiquitous, rapidly growing species of nontuberculous mycobacteria that colonizes organic surfaces and is frequently associated with opportunistic infections in humans. We report here the draft genome sequence of Mycobacterium abscessus strain M139, which shows genomic features reported to be characteristic of both Mycobacterium abscessus subsp. abscessus and Mycobacterium abscessus subsp. massiliense.
  17. Choo SW, Wong YL, Leong ML, Heydari H, Ong CS, Ng KP, et al.
    J Bacteriol, 2012 Oct;194(20):5724.
    PMID: 23012295
    Mycobacterium abscessus is a species of rapidly growing nontuberculous mycobacteria that is frequently associated with opportunistic infections in humans. Here, we report the annotated genome sequence of M. abscessus strain M94, which showed an unusual cluster of tRNAs.
  18. Wong YL, Choo SW, Tan JL, Ong CS, Ng KP, Ngeow YF
    J Bacteriol, 2012 Aug;194(16):4475.
    PMID: 22843600 DOI: 10.1128/JB.00916-12
    The whole-genome sequence of Mycobacterium bolletii M24, isolated from the bronchoalveolar lavage fluid of a Malaysian patient, is reported here. The circular chromosome of 5,507,730 bp helped to clarify the taxonomic position of this organism within the M. abscessus complex and revealed the presence of proteins potentially important for pathogenicity in a human host.
  19. Ngeow YF, Wong YL, Lokanathan N, Wong GJ, Ong CS, Ng KP, et al.
    J Bacteriol, 2012 Sep;194(17):4786.
    PMID: 22887681 DOI: 10.1128/JB.01104-12
    We report the draft genome sequence of a clinical isolate, strain M115, identified as Mycobacterium massiliense, a member of the newly created taxon of Mycobacterium abscessus subspecies bolletii comb. nov.
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