Displaying publications 41 - 60 of 140 in total

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  1. Sulaiman H, Atiya N, Loi KW, Ng KP
    Eur J Intern Med, 2016 Nov;35:e7-e8.
    PMID: 27498273 DOI: 10.1016/j.ejim.2016.07.014
  2. 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.
  3. Tan JL, Ng KP, Ong CS, Ngeow YF
    Front Microbiol, 2017;8:2042.
    PMID: 29109707 DOI: 10.3389/fmicb.2017.02042
    Mycobacterium abscessus, a rapid-growing non-tuberculous mycobacterium, has been the cause of sporadic and outbreak infections world-wide. The subspecies in M. abscessus complex (M. abscessus, M. massiliense, and M. bolletii) are associated with different biologic and pathogenic characteristics and are known to be among the most frequently isolated opportunistic pathogens from clinical material. To date, the evolutionary forces that could have contributed to these biological and clinical differences are still unclear. We compared genome data from 243 M. abscessus strains downloaded from the NCBI ftp Refseq database to understand how the microevolutionary processes of homologous recombination and positive selection influenced the diversification of the M. abscessus complex at the subspecies level. The three subspecies are clearly separated in the Minimum Spanning Tree. Their MUMi-based genomic distances support the separation of M. massiliense and M. bolletii into two subspecies. Maximum Likelihood analysis through dN/dS (the ratio of number of non-synonymous substitutions per non-synonymous site, to the number of synonymous substitutions per synonymous site) identified distinct genes in each subspecies that could have been affected by positive selection during evolution. The results of genome-wide alignment based on concatenated locally-collinear blocks suggest that (a) recombination has affected the M. abscessus complex more than mutation and positive selection; (b) recombination occurred more frequently in M. massiliense than in the other two subspecies; and (c) the recombined segments in the three subspecies have come from different intra-species and inter-species origins. The results lead to the identification of possible gene sets that could have been responsible for the subspecies-specific features and suggest independent evolution among the three subspecies, with recombination playing a more significant role than positive selection in the diversification among members in this complex.
  4. 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 
  5. Chiu CL, Mansor M, Ng KP, Chan YK
    Int J Obstet Anesth, 2003 Jan;12(1):23-7.
    PMID: 15676316
    A 5-year retrospective survey of anaesthesia for caesarean section for mild/moderate and severe preeclampsia was performed, covering the period between 1 January 1996 and 31 December 2000. One hundred and twenty-one cases of non-labouring preeclamptic patients receiving spinal or epidural anaesthesia for caesarean section were included for analysis. Comparisons were made of the lowest blood pressures recorded before induction of anaesthesia, during the period from induction to delivery and the period from delivery to the end of operation. The decreases in blood pressure were similar after spinal and epidural anaesthesia. The use of intravenous fluids and ephedrine were also comparable in the two anaesthetic groups. There was no difference in maternal or neonatal outcome. Our result supports the use of spinal anaesthesia in preeclamptic women.
  6. Ho SH, Ng KP, Kaur H, Goh KL
    Hepatobiliary Pancreat Dis Int, 2015 Jun;14(3):281-6.
    PMID: 26063029
    BACKGROUND: Genotypes of hepatitis C virus (HCV) are distributed differently across the world. There is a paucity of such data in a multi-ethnic Asian population like Malaysia. The objectives of this study were to determine the distribution of HCV genotypes between major ethnic groups and to ascertain their association with basic demographic variables like age and gender.

    METHODS: This was a cross-sectional prospective study conducted from September 2007 to September 2013. Consecutive patients who were detected to have anti-HCV antibodies in the University of Malaya Medical Centre were included and tested for the presence of HCV RNA using Roche Cobas Amplicor Analyzer and HCV genotype using Roche single Linear Array HCV Genotyping strip.

    RESULTS: Five hundred and ninety-six subjects were found to have positive anti-HCV antibodies during this period of time. However, only 396 (66.4%) were HCV RNA positive and included in the final analysis. Our results showed that HCV genotype 3 was the predominant genotype with overall frequency of 61.9% followed by genotypes 1 (35.9%), 2 (1.8%) and 6 (0.5%). There was a slightly higher prevalence of HCV genotype 3 among the Malays when compared to the Chinese (P=0.043). No other statistical significant differences were observed in the distribution of HCV genotypes among the major ethnic groups. There was also no association between the predominant genotypes and basic demographic variables.

    CONCLUSIONS: In a multi-ethnic Asian society in Malaysia, genotype 3 is the predominant genotype among all the major ethnic groups with genotype 1 as the second commonest genotype. Both genotypes 2 and 6 are uncommon. Neither genotype 4 nor 5 was detected. There is no identification of HCV genotype according to ethnic origin, age and gender.

  7. Tay ST, Tanty Haryanty T, Ng KP, Rohani MY, Hamimah H
    Mycoses, 2006 Jul;49(4):324-30.
    PMID: 16784448
    The in vitro susceptibilities of Malaysian clinical isolates of Cryptococcus neoformans var. grubii and C . gattii to five antifungal drugs (amphotericin B, flucytosine, fluconazole, itraconazole and ketoconazole) were determined using the Etest method. None of the Malaysian isolates was resistant to amphotericin B and ketoconazole. Isolates resistant to flucytosine, fluconazole and itraconazole were observed in this study. Minimum inhibition concentrations (MICs) of > or = 32 microg ml(-1) against flucytosine, > or = 64 microg ml(-1) against fluconazole and > or = 1 microg ml(-1) against itraconazole were noted in four (8.3%), two (4.2%) and one (2.1%) isolates respectively. There was no significant difference in the MICs for both Cryptococcus species (P > 0.05), indicating that C. gattii was as susceptible as var. grubii to all the antifungal drugs tested. No significant difference in the MICs for both Cryptococcus species collected from 1980 to 1990 and 2002 to 2004 were observed (P > 0.05).
  8. 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.
  9. Tay ST, Lotfalikhani A, Sabet NS, Ponnampalavanar S, Sulaiman S, Na SL, et al.
    Mycopathologia, 2014 Oct;178(3-4):307-14.
    PMID: 25022264 DOI: 10.1007/s11046-014-9778-9
    BACKGROUND: Candida nivariensis and C. bracarensis have been recently identified as emerging yeast pathogens which are phenotypically indistinguishable from C. glabrata. However, there is little data on the prevalence and antifungal susceptibilities of these species.

    OBJECTIVE: This study investigated the occurrence of C. nivariensis and C. bracarensis in a culture collection of 185 C. glabrata isolates at a Malaysian teaching hospital.

    METHODS: C. nivariensis was discriminated from C. glabrata using a PCR assay as described by Enache-Angoulvant et al. (J Clin Microbiol 49:3375-9, 2011). The identity of the isolates was confirmed by sequence analysis of the D1D2 domain and internal transcribed spacer region of the yeasts. The isolates were cultured on Chromogenic CHROMagar Candida (®) agar (Difco, USA), and their biochemical and enzymic profiles were determined. Antifungal susceptibilities of the isolates against amphotericin B, fluconazole, voriconazole and caspofungin were determined using E tests. Clotrimazole MICs were determined using a microbroth dilution method.

    RESULTS: There was a low prevalence (1.1 %) of C. nivariensis in our culture collection of C. glabrata. C. nivariensis was isolated from a blood culture and vaginal swab of two patients. C. nivariensis grew as white colonies on Chromogenic agar and demonstrated few positive reactions using biochemical tests. Enzymatic profiles of the C. nivariensis isolates were similar to that of C. glabrata. The isolates were susceptible to amphotericin B, fluconazole, voriconazole and caspofungin. Clotrimazole resistance is suspected in one isolate.

    CONCLUSION: This study reports for the first time the emergence of C. nivariensis in our clinical setting.

  10. Lee PY, Gam LH, Yong VC, Rosli R, Ng KP, Chong PP
    J Appl Microbiol, 2014 Sep;117(3):854-65.
    PMID: 24909754 DOI: 10.1111/jam.12562
    This study was conducted to identify antigenic proteins of Candida tropicalis that are targeted by the host immune system.
  11. Lee PY, Gam LH, Yong VC, Rosli R, Ng KP, Chong PP
    J Appl Microbiol, 2014 Apr;116(4):999-1009.
    PMID: 24299471 DOI: 10.1111/jam.12408
    Systemic candidiasis is the leading fungal bloodstream infection, and its incidence has been on the rise. Recently, Candida parapsilosis has emerged as an increasingly prevalent fungal pathogen, but little is known about its antigenic profile. Hence, the current work was performed to discover immunogenic proteins of C. parapsilosis using serological proteome analysis.
  12. Al-Darraji HA, Abd Razak H, Ng KP, Altice FL, Kamarulzaman A
    PLoS One, 2013;8(9):e73717.
    PMID: 24040038 DOI: 10.1371/journal.pone.0073717
    Delays in tuberculosis (TB) diagnosis, particularly in prisons, is associated with detrimental outcomes. The new GeneXpert MTB/RIF assay (Xpert) offers accurate and rapid diagnosis of active TB, but its performance in improving case detection in high-transmission congregate settings has yet to be evaluated. We assessed the diagnostic accuracy of a single Xpert assay in an intensified case finding survey among HIV-infected prisoners in Malaysia.
  13. 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.
  14. Keng TC, Ng KP, Tan LP, Chong YB, Wong CM, Lim SK
    Ren Fail, 2012;34(6):804-6.
    PMID: 22506572 DOI: 10.3109/0886022X.2012.678208
    Peritonitis is well recognized as the Achilles tendon of peritoneal dialysis (PD). Reoccurrence of peritonitis due to the same organism, defined as either repeat or relapsing peritonitis under the 2005 guidelines by the International Society for Peritoneal Dialysis, often results in PD technique failure. Rothia dentocariosa, a low-virulent human oropharynx commensal, is a rarely reported pathogen in human infection, particularly infective endocarditis. R. dentocariosa PD-related peritonitis is exceedingly uncommon yet potentially results in repeat or relapsing peritonitis which requires catheter removal. We report a case of R. dentocariosa repeat and relapsing peritonitis in a PD patient who was treated successfully with antimicrobial therapy.
  15. Muhammad Iqbal AH, Lim SK, Ng KP, Tan LP, Chong YB, Keng TC
    Transpl Infect Dis, 2012 Aug;14(4):E23-6.
    PMID: 22551151 DOI: 10.1111/j.1399-3062.2012.00738.x
    Pneumocystis jirovecii (formerly Pneumocystis carinii) pneumonia (PCP) is a rare but serious infection that usually occurs within a year after solid organ transplantation. PCP may occur after 1 year post transplantation, but the rate is reported to be very low. Studies have shown an association between cytomegalovirus (CMV) infection in solid organ transplant patients and an increased risk of opportunistic infection. This increased risk is thought to be a result of the immunomodulatory effects of the CMV infection. We present a case of PCP infection occurring 13 years after a renal transplantation. This occurred following a recurrent CMV infection while the patient was on low-dose immunosuppressants.
  16. Karunakaran R, Halim HA, Ng KP, Hanifah YA, Chin E, Jaafar FL, et al.
    Eur Rev Med Pharmacol Sci, 2011 Nov;15(11):1343-6.
    PMID: 22195371
    Tsukamurella spp. are a rare but important cause of intravascular catheter-related bacteremia in immunocompromised patients. The organism is an aerobic, Gram-positive, weakly acid-fast bacillus that is difficult to differentiate using standard laboratory methods from other aerobic actinomycetales such as Nocardia spp., Rhododoccus spp., Gordonia spp., and the rapid growing Mycobacterium spp. We report a case of Tsukamurella tyrosinosolvens catheter-related bacteremia in a 51-year-old haematology patient who responded to treatment with imipenem and subsequent line removal. 16srRNA sequencing allowed for the prompt identification of this organism.
  17. 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.
  18. Tee KK, Li XJ, Nohtomi K, Ng KP, Kamarulzaman A, Takebe Y
    J Acquir Immune Defic Syndr, 2006 Dec 15;43(5):523-9.
    PMID: 17031320
    A molecular epidemiological investigation was conducted among various risk populations (n = 184) in Kuala Lumpur, Malaysia, in 2003 to 2005, on the basis of nucleotide sequences of protease and reverse transcriptase regions. In addition to circulating HIV-1 strains, including CRF01_AE (57.1%), subtype B (20.1%), and subtype C (0.5%), we detected a candidate with a new circulating recombinant form (CRF). We determined four near-full-length nucleotide sequences with identical subtype structure from epidemiologically unlinked individuals of different risk and ethnic groups. In this chimera, two short subtype B segments were inserted into the gag-RT region in a backbone of CRF01_AE. The recombinant structure was distinct from previously identified CRF15_01B in Thailand. In agreement with the current HIV nomenclature system, this constitutes a novel CRF (CRF33_01B). The overall prevalence of CRF33_01B is 19.0% (35/184). Although the prevalence of CRF33_01B is particularly high among injecting drug users (42.0%, 21/50), it is also detected in a substantial proportion of homo-/bisexual males (18.8%, 3/16) and heterosexuals (9.8%, 9/92). Moreover, unique recombinant forms composed of CRF01_AE and subtype B that have a significant structural relationship with CRF33_01B were detected in 1.6% (3/184) of study subjects, suggesting an ongoing recombination process in Malaysia. This new CRF seems to be bridging viral transmission between different risk populations in this country.
  19. Puthucheary SD, Ng KP, Hafeez A, Raja NS, Hassan HH
    PMID: 15691137
    Persons infected with human immunodeficiency virus (HIV) have an increased risk of salmonellosis when compared to the general population. We describe seven such patients with Salmonella bacteremia, of whom two had recurrent salmonellosis. In the latter two cases the infection was unusually severe, characterized by widespread infection, bacteremia and relapse, despite standard antimicrobial therapy. HIV-infected individuals will benefit from education on the source of Salmonella, mode of acquisition and prevention through safe food handling and food preparation practices. Because of the difficulty of eradicating Salmonella infection in patients with acquired immunodeficiency syndrome, long-term suppressive treatment with antimicrobials is warranted.
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