Displaying publications 1 - 20 of 140 in total

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  1. Tee KK, Pon CK, Kamarulzaman A, Ng KP
    AIDS, 2005 Jan 28;19(2):119-26.
    PMID: 15668536
    OBJECTIVES: To investigate the molecular epidemiology of HIV-1 and to screen for the emergence of intersubtype recombinants in Kuala Lumpur, Malaysia.

    DESIGN: A molecular epidemiology study was conducted among HIV-1 seropositive patients attending the University Malaya Medical Center (UMMC) from July 2003 to June 2004.

    METHODS: Protease (PR) and reverse transcriptase (RT) gene sequences were derived from drug resistance genotyping assay of 100 newly diagnosed or antiretroviral-naive patients. These were phylogenetically analysed to determine the subtypes and recombination breakpoint analyses were performed on intersubtype recombinants to estimate the recombination breakpoint(s).

    RESULTS: CRF01_AE predominated in Kuala Lumpur with 65% in both PR and RT genes. B subtype was detected at 14% and 12% in PR and RT genes, respectively. C subtype was present at 1% in both genes. Overall, the concordance of PR and RT genes in discriminating subtypes/circulating recombinant forms (CRF) was high at 96%. In this study, novel CRF01_AE/B intersubtype recombinants were detected at high prevalence (22%), including those isolates with subtype discordance. Thai variants of CRF01_AE and B subtype were involved in the genesis of these unique recombinant forms (URF). Interestingly, 19 CRF01_AE/B intersubtype recombinant isolates shared similar recombination breakpoints in both PR and RT genes. Several distinct URF were also identified.

    CONCLUSION: PR and RT genes can be utilized for subtype/CRF assessment with high degree of agreement, allowing concurrent surveillance of circulating HIV-1 subtypes with antiretroviral drug resistance genotyping tests. The emergence of highly identical CRF01_AE/B intersubtype recombinants suggests the possibility of the appearance of a new circulating recombinant form in Kuala Lumpur.

  2. Tee KK, Kamarulzaman A, Ng KP
    AIDS Res Hum Retroviruses, 2006 Feb;22(2):121-4.
    PMID: 16478392
    To assess the prevalence of mutations associated with drug resistance in antiretroviral-naive patients in Kuala Lumpur, Malaysia, genotypic resistance testing was conducted among drug-naive HIV-1 patients attending the University Malaya Medical Center (UMMC) between July 2003 and June 2004. Reverse transcriptase (RT) and protease genes of plasma virions were sequenced from 100 individuals. The majority of the patients were recently diagnosed. Codons 20-255 of the RT and 1-96 of the protease gene were examined for major and minor mutations associated with antiretroviral resistance reported by the International AIDS Society- USA (IAS-USA) Drug Resistance Mutations Group. The prevalence of patients with at least one major mutation conferring drug resistance was 1%, with only one patient having a Y181C amino acid substitution in the RT gene that confers high-level resistance to nevirapine and delavirdine. Minor mutations were detected in high prevalence in the protease gene. Amino acid substitutions I13V, E35D, and M36I were associated with CRF01_AE while L63P, V77I, and I93L were associated with subtype B. Baseline prevalence of major mutations associated with resistance to antiretroviral drugs was low among antiretroviral-naive HIV-1 patients, suggesting that routine drug resistance testing may be unnecessary for all individuals newly diagnosed with HIV or all patients beginning antiretroviral therapy.
  3. 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.
  4. 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.
  5. Guad RM, Ng KP, Lim SK, Hirayama K, Eng HS, Wan Md Adnan WAH
    Ann Acad Med Singap, 2019 Dec;48(12):403-411.
    PMID: 32112065
    INTRODUCTION: Studies have shown that a compatible human leukocyte antigen (HLA) match can confer a favourable effect on graft outcomes. We examined the outcomes of HLA matching in renal transplant donors in Malaysia.

    MATERIALS AND METHODS: A total of 140 patients who had compatible ABO blood type with negative T-cell lymphocytotoxicity crossmatch were included in the study and 25% of them were spousal transplant donors. No remarkable differences in acute rejection rate, graft survival, patient survival and serum creatinine level were observed between the spousal and living-related donor groups.

    RESULTS: The spousal donor group had a higher degree of HLA mismatch than the living-related donor group. HLA-A mismatch was associated with increased rejection risk at 6 months (odds ratio [OR], 2.75; P = 0.04), 1 year (OR, 2.54; P = 0.03) and 3 years (OR, 3.69; P = 0.001). It was also observed in the deleterious effects of HLA-B and HLA-DQ loci when the number of antigen mismatches increased. The risk was 7 times higher in patients with ≥1 mismatch at HLA-A, HLA-B and HLA-DR loci than those who did not have a mismatch at these loci at 6 months (P = 0.01), 1 year (P = 0.03) and 3 years (P = 0.003).

    CONCLUSION: A good match for HLA-A, HLA-B, HLA-DR and HLA-DQ can prevent acute rejection risk in renal transplant patients. Consequently, spousal donor transplants could be a safe intervention in renal patients.

  6. Tumin M, Tafran K, Zakaria RH, Satar NM, Ng KP, Lim SK
    Ann. Transplant., 2015 Dec 22;20:752-6.
    PMID: 26690676 DOI: 10.12659/aot.894427
    BACKGROUND: Malaysia, which currently uses the informed consent system (ICS), is suffering from a severe shortage of organs for transplantation. Family members of dialysis patients (FMDPs) are expected to have a positive attitude toward deceased organ donation (DOD) because they have a close relative in need of a kidney donation. This study explores FMDPs' attitude toward DOD under the ICS and the presumed consent system (PCS).

    MATERIAL/METHODS: The attitude of 350 FMDPs toward DOD under the ICS and PCS were sought between June and October 2013 in 3 dialysis institutions in Kuala Lumpur, Malaysia.

    RESULTS: Under the ICS, 6.6% of respondents were registered donors, 6.6% were ready to register at the time of the survey, 38.6% were willing to donate but not ready to register at the time of the survey, and 48.2% were unwilling to donate organs upon death. If the PCS were implemented, 57.7% of respondents (28.7% of the willing donors and 88.7% of the unwilling respondents) stated that they would officially object to organ donation.

    CONCLUSIONS: FMDPs' attitude toward DOD is not more positive or significantly better than that of the general public (based on earlier studies). The PCS may increase the number of donors, but it may also worsen the attitude of FMDPs toward DOD. Strategies aiming to promote DOD in Malaysia should be revised, and should perhaps be focused on enhancing trust of the medical system.
  7. Tumin M, Abdul Talib Abdul Mutalib M, Mohd Satar N, Abdullah N, Chong CS, Ng KP, et al.
    Ann. Transplant., 2014;19:112-8.
    PMID: 24584108 DOI: 10.12659/AOT.889490
    Informed consent of prospective donors should include information about the quality of life (QoL) of existing donors, especially those within the relevant country. This study aimed to provide information on Malaysian organ donors' QoL relative to a control group.
  8. Tumin M, Noh A, Chong CS, Mohd Satar N, Lim SK, Abdullah N, et al.
    Ann. Transplant., 2013;18:314-9.
    PMID: 23792535 DOI: 10.12659/AOT.883957
    This paper aimed to assess the willingness of Malaysians with post-secondary education to be living kidney donors.
  9. Chan CL, Yew SM, Ngeow YF, Na SL, Lee KW, Hoh CC, et al.
    BMC Genomics, 2015 Nov 18;16:966.
    PMID: 26581579 DOI: 10.1186/s12864-015-2200-2
    BACKGROUND: Daldinia eschscholtzii is a wood-inhabiting fungus that causes wood decay under certain conditions. It has a broad host range and produces a large repertoire of potentially bioactive compounds. However, there is no extensive genome analysis on this fungal species.

    RESULTS: Two fungal isolates (UM 1400 and UM 1020) from human specimens were identified as Daldinia eschscholtzii by morphological features and ITS-based phylogenetic analysis. Both genomes were similar in size with 10,822 predicted genes in UM 1400 (35.8 Mb) and 11,120 predicted genes in UM 1020 (35.5 Mb). A total of 751 gene families were shared among both UM isolates, including gene families associated with fungus-host interactions. In the CAZyme comparative analysis, both genomes were found to contain arrays of CAZyme related to plant cell wall degradation. Genes encoding secreted peptidases were found in the genomes, which encode for the peptidases involved in the degradation of structural proteins in plant cell wall. In addition, arrays of secondary metabolite backbone genes were identified in both genomes, indicating of their potential to produce bioactive secondary metabolites. Both genomes also contained an abundance of gene encoding signaling components, with three proposed MAPK cascades involved in cell wall integrity, osmoregulation, and mating/filamentation. Besides genomic evidence for degrading capability, both isolates also harbored an array of genes encoding stress response proteins that are potentially significant for adaptation to living in the hostile environments.

    CONCLUSIONS: Our genomic studies provide further information for the biological understanding of the D. eschscholtzii and suggest that these wood-decaying fungi are also equipped for adaptation to adverse environments in the human host.

  10. Yew SM, Chan CL, Kuan CS, Toh YF, Ngeow YF, Na SL, et al.
    BMC Genomics, 2016 Feb 03;17:91.
    PMID: 26842951 DOI: 10.1186/s12864-016-2409-8
    Ochroconis mirabilis, a recently introduced water-borne dematiaceous fungus, is occasionally isolated from human skin lesions and nails. We identified an isolate of O. mirabilis from a skin scraping with morphological and molecular studies. Its genome was then sequenced and analysed for genetic features related to classification and biological characteristics.
  11. Jalalonmuhali M, Lim SK, Md Shah MN, Ng KP
    BMC Nephrol, 2017 Dec 13;18(1):363.
    PMID: 29237422 DOI: 10.1186/s12882-017-0776-2
    BACKGROUND: Accurate measurement of renal function is important: however, radiolabelled gold standard measurement of GFR is highly expensive and can only be used on a very limited scale. We aim to compare the performance of Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equations in the multi-ethnic population attending University Malaya Medical Centre (UMMC).
    METHODS: This is a cross-sectional study recruiting patients, who attend UMMC Nephrology clinics on voluntary basis. 51-Chromium EDTA (51Cr-EDTA) plasma level was used to measure the reference GFR. The serum creatinine was determined by IDMS reference modified Jaffe kinetic assay (CrJaffe). The predictive capabilities of MDRD and CKD-EPI based equations were calculated. Data was analysed using SPSS version 20 and correlation, bias, precision and accuracy were determined.
    RESULTS: A total of 113 subjects with mean age of 58.12 ± 14.76 years and BMI of 25.99 ± 4.29 kg/m2 were recruited. The mean reference GFR was 66.98 ± 40.65 ml/min/1.73m2, while the estimated GFR based on MDRD and CKD-EPI formula were 62.17 ± 40.40, and 60.44 ± 34.59, respectively. Both MDRD and CKD-EPI were well-correlated with reference GFR (0.806 and 0.867 respectively) and statistically significant with p 
  12. Thye CK, Lee YW, Jalalonmuhali M, Lim SK, Ng KP
    BMC Nephrol, 2023 Sep 11;24(1):267.
    PMID: 37691129 DOI: 10.1186/s12882-023-03057-w
    BACKGROUND: Assessment of donor renal function is made by the measurement of Glomerular Filtration Rate (GFR). Exogenous markers are preferred over creatinine clearance and are widely used for measuring GFR. However, they are difficult to obtain, costly and laborious. This is a study to look into the safety and accuracy of creatinine clearance for renal assessment among the living kidney donors in the Malaysian population.

    METHODS: This is a retrospective, single-centre study comprising 105 living kidney donor candidates from the year 2007 to 2020. By comparing against 51-Chromium ethylenediamine-tetraacetic acid (51Cr-EDTA), we analysed creatinine clearance for correlation, bias, precision and accuracy.

    RESULTS: The study group had a mean age of 45.68 ± 10.97 years with a mean serum creatinine of 64.43 ± 17.68 µmol/L and a urine volume of 2.06 ± 0.83 L. Mean measured GFR from 51Cr-EDTA was 124.37 ± 26.83 ml/min/1.73m2 whereas mean creatinine clearance was 132.35 ± 38.18 ml/min/1.73m2. Creatinine clearance overestimated 51Cr-EDTA significantly with a correlation coefficient of 0.48 (p 

  13. Cheong WH, Tan YC, Yap SJ, Ng KP
    Bioinformatics, 2015 Nov 15;31(22):3685-7.
    PMID: 26227146 DOI: 10.1093/bioinformatics/btv433
    : We present ClicO Free Service, an online web-service based on Circos, which provides a user-friendly, interactive web-based interface with configurable features to generate Circos circular plots.
  14. Kuan CS, Ng KP, Yew SM, Umar Meleh H, Seow HF, How KN, et al.
    Braz J Microbiol, 2023 Sep;54(3):1351-1372.
    PMID: 37351789 DOI: 10.1007/s42770-023-01032-z
    Neoscytalidium dimidiatum and Bipolaris species are fungal plant pathogens that have been reported to cause human diseases. Recently, we have isolated numerous N. dimidiatum and Bipolaris species from the skin scrapings and nails of different patients. In this work, we have sequenced the genome of one strain of N. dimidiatum. The sequenced genome was compared to that of a previously reported Bipolaris papendorfii genome for a better understanding of their complex lifestyle and broad host-range pathogenicity. Both N. dimidiatum UM 880 (~ 43 Mb) and B. papendorfii UM 226 (~ 33 Mb) genomes include 11,015-12,320 putative coding DNA sequences, of which 0.51-2.49% are predicted transposable elements. Analysis of secondary metabolism gene clusters revealed several genes involved in melanin biosynthesis and iron uptake. The arsenal of CAZymes related to plants pathogenicity is comparable between the species, including genes involved in hemicellulose and pectin decomposition. Several important gene encoding keratinolytic peptidases were identified in N. dimidiatum and B. papendorfii, reflecting their potential pathogenic role in causing skin and nail infections. In this study, additional information on the metabolic features of these two species, such as nutritional profiling, pH tolerance, and osmotolerant, are revealed. The genomic characterization of N. dimidiatum and B. papendorfii provides the basis for the future functional studies to gain further insights as to what makes these fungi persist in plants and why they are pathogenic to humans.
  15. Poh ME, Liam CK, Ng KP, Tan R
    Chest, 2014 Apr;145(4):858-860.
    PMID: 24687707 DOI: 10.1378/chest.13-1952
    We describe the first case, to our knowledge, of Mycobacterium brisbanense species nova with the type strain W6743T (=ATCC 49938T=DSM 44680T) isolated from the lungs of a man with a 6-month history of productive cough and intermittent fever presenting with acute hypoglycemia. A CT scan of the thorax revealed multiple small nodules and consolidation over both lungs with cavitation. Sputum culture repeatedly grew M brisbanense species nova, a novel species never before isolated in Malaysia. The case met the American Thoracic Society criteria for the diagnosis of nontuberculous mycobacterial infection. There was dramatic clinical and radiologic response to treatment with an empirical combination of rifampicin, ethambutol, and levofloxacin and subsequently clarithromycin and levofloxacin once sensitivity was known. This report is the first, to our knowledge, of the pathogen isolated in a patient with chronic cavitary lung infection since it was first identified from an antral sinus in Brisbane, Queensland, Australia, and the first time it is isolated from a human subject in Malaysia.
  16. Wong FN, Tan JA, Keng TC, Ng KP, Chua KH, Kuppusamy UR
    Clin Chim Acta, 2016 Jan 30;453:56-61.
    PMID: 26657980 DOI: 10.1016/j.cca.2015.12.002
    BACKGROUND: This study aimed to investigate the relationship between soluble RAGE and estimated glomerular filtration rate (eGFR) in patients with chronic kidney disease (CKD) after controlling for the potential confounding factors such as medication usage and enzymatic antioxidants.
    METHODS: A total of 222 CKD patients whose eGFR is less than 60ml/min/1.73m(2) and 111 non-CKD individuals were recruited. The study subjects were classified based on their diabetes status. The plasma glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities as well as plasma soluble RAGE level were measured.
    RESULTS: The plasma GPx and SOD activities were significantly lower and the plasma soluble RAGE level was significantly higher in the CKD patients than in the non-CKD individuals, regardless of the diabetes status. Soluble RAGE was significantly correlated with eGFR in both diabetic CKD (D-CKD) and non-diabetic CKD (ND-CKD) patients. The association between soluble RAGE and eGFR remained largely unaffected by the confounding factors in D-CKD patients. However, the confounding effect of enzymatic antioxidants in the relationship between eGFR and soluble RAGE was observed in ND-CKD patients.
    CONCLUSION: The increased plasma level of soluble RAGE is a better indicator of renal function decline in diabetic CKD patients instead of non-diabetic CKD patients.
    KEYWORDS: Chronic kidney disease; Diabetes; Enzymatic antioxidants; Glomerular filtration rate; Medications; Soluble RAGE
  17. 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.
  18. 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.
  19. Lau KA, Wang B, Miranda-Saksena M, Boadle R, Kamarulzaman A, Ng KP, et al.
    Curr. HIV Res., 2010 Apr;8(3):259-71.
    PMID: 20214658
    In Malaysia, co-circulation of CRF01_AE and subtype B has resulted in the emergence of the second generation derivative; CRF33_01B in approximately 20% of its HIV-1 infected individuals. Our objective was to identify possible biological advantages that CRF33_01B possesses over its progenitors. Biological and molecular comparisons of CRF33_01B against its parental subtypes clearly show that CRF33_01B replicated better in activated whole peripheral blood mononuclear cells (PBMCs) and CD4+ T-lymphocytes, but not monocyte-derived macrophages (MDMs). Also, its acquired fitness was greater than CRF01_AE but not subtype B. Moreover, CRF33_01B has higher rate of apoptotic cell death and syncytia induction compared to subtype B. These adaptive and survival abilities could have been acquired by CRF33_01B due to the incorporation of subtype B fragments into the gag-RT region of its full-length genome. Our studies confirm the previously held belief that HIV-1 strains may harbor enhanced biological fitness upon recombination. We therefore estimate a possible gradual replacement of the current predominance of CRF01_AE, as well as wider dissemination of CRF33_01B, together with the identification of other new CRF01_AE/B inter-subtype recombinants in Malaysia.
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