Displaying publications 81 - 100 of 191 in total

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  1. Fulltext Formation of biofilm by Listeria monocytogenes ATCC 19112 at different incubation temperatures and concentrations of sodium chloride
    Lee HY, Chai LC, Pui CF, Mustafa S, Cheah YK, Nishibuchi M, et al.
    Braz J Microbiol, 2013;44(1):51-5.
    PMID: 24159283 DOI: 10.1590/S1517-83822013005000004
    Biofilm formation can lead to various consequences in the food processing line such as contamination and equipment breakdowns. Since formation of biofilm can occur in various conditions; this study was carried out using L. monocytogenes ATCC 19112 and its biofilm formation ability tested under various concentrations of sodium chloride and temperatures. Cultures of L. monocytogenes ATCC 19112 were placed in 96-well microtitre plate containing concentration of sodium chloride from 1-10% (w/v) and incubated at different temperature of 4 °C, 30 °C and 45 °C for up to 60 h. Absorbance reading of crystal violet staining showed the density of biofilm formed in the 96-well microtitre plates was significantly higher when incubated in 4 °C. The formation of biofilm also occurs at a faster rate at 4 °C and higher optical density (OD 570 nm) was observed at 45 °C. This shows that storage under formation of biofilm that may lead to a higher contamination along the processing line in the food industry. Formation of biofilm was found to be more dependent on temperature compared to sodium chloride stress.
  2. Malaysianol B, an oligostilbenoid derivative from Dryobalanops lanceolata
    Wibowo A, Ahmat N, Hamzah AS, Low AL, Mohamad SA, Khong HY, et al.
    Fitoterapia, 2012 Dec;83(8):1569-75.
    PMID: 22982329 DOI: 10.1016/j.fitote.2012.09.004
    A new oligostilbenoid tetramer, malaysianol B (1), was isolated from the acetone extract of the stem bark of Dryobalanops lanceolata along with seven oligostilbenoids tetramers; hopeaphenol (2), stenophyllol A (3), nepalensinol B (4), vaticanol B (5) and C (6), upunaphenol D (7), and flexuosol A (8). The structures of the isolated compounds were established on the basis of their spectroscopic data evidence. The antibacterial activity of the isolated compounds was evaluated using resazurin microtitre-plate assay.
  3. ALEXIS O-Ring wound retractor vs conventional wound protection for the prevention of surgical site infections in colorectal resections(1)
    Cheng KP, Roslani AC, Sehha N, Kueh JH, Law CW, Chong HY, et al.
    Colorectal Dis, 2012 Jun;14(6):e346-51.
    PMID: 22568647 DOI: 10.1111/j.1463-1318.2012.02943.x
    Surgical site infection (SSI) remains a common postoperative morbidity, particularly in colorectal resections, and poses a significant financial burden to the healthcare system. The omission of mechanical bowel preparation, as is performed in enhanced recovery after surgery programmes, appears to further increase the incidence. Various wound protection methods have been devised to reduce the incidence of SSIs. However, there are few randomized controlled trials assessing their efficacy. The aim of this study is to investigate whether ALEXIS wound retractors with reinforced O-rings are superior to conventional wound protection methods in preventing SSIs in colorectal resections.
  4. A prospective, randomised, double-blinded trial to study the efficacy of topical tocotrienol in the prevention of hypertrophic scars
    Khoo TL, Halim AS, Zakaria Z, Mat Saad AZ, Wu LY, Lau HY
    J Plast Reconstr Aesthet Surg, 2011 Jun;64(6):e137-45.
    PMID: 20869928 DOI: 10.1016/j.bjps.2010.08.029
    Despite widespread beliefs regarding the use of topical tocotrienol in the prevention of hypertrophic scars, there is very little evidence from well controlled and randomised clinical trials to justify its benefits for surgical scars.
  5. Fulltext Immunological profiles of immune restoration disease presenting as mycobacterial lymphadenitis and cryptococcal meningitis
    Tan DB, Yong YK, Tan HY, Kamarulzaman A, Tan LH, Lim A, et al.
    HIV Med, 2008 May;9(5):307-16.
    PMID: 18400078 DOI: 10.1111/j.1468-1293.2008.00565.x
    A proportion of HIV patients beginning antiretroviral therapy (ART) develop immune restoration disease (IRD). Immunological characteristics of IRD were investigated in a cohort of HIV patients beginning therapy in Kuala Lumpur, Malaysia.
  6. Fulltext Outpatient pre-operative assessment in joint replacement surgery
    Chan CY, Nam HY, Raveenthiran R, Choon SK, Tai CC
    Med J Malaysia, 2008 Jun;63(2):100-3.
    PMID: 18942292 MyJurnal
    An anaesthetist-led outpatient pre-operative assessment (OPA) clinic was introduced in our unit in an effort to improve patient care and cost-effectiveness. To assess the efficiency of the clinic, 112 patients who attended the OPA clinic (attendance rate 98%) during the first year were assessed prospectively and compared with 118 patients who did not undergo OPA the year before. There were fewer cancellations among those who attended the OPA clinic (13.6% compared to 3.6%), and the hospital stay was shortened from an average of 10.7 days to 7.0 days. This has resulted in more efficient utilization of operating theatre, reduced hospital costs and improved patient satisfaction. More extensive use of the pre-admission clinic is recommended and should be explored in other clinical settings.
    Study site: Outpatient Preoperative Assessment (OPA) clinic, University Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia
  7. Nutrient composition, antioxidant properties, and anti-proliferative activity of Lignosus rhinocerus Cooke sclerotium
    Yap YH, Tan N, Fung S, Aziz AA, Tan C, Ng S
    J Sci Food Agric, 2013 Sep;93(12):2945-52.
    PMID: 23460242 DOI: 10.1002/jsfa.6121
    Lignosus rhinocerus (tiger milk mushroom) is an important medicinal mushroom used in Southeast Asia and China, and its sclerotium can be developed into functional food/nutraceuticals. The nutrient composition, antioxidant properties, and anti-proliferative activity of wild type and a cultivated strain of L. rhinocerus sclerotia were investigated.
  8. Potential Health And Economic Impact Of Introducing A Dengue Vaccine In Malaysia: Assessment Using Dynamic Transmission Modelling
    Yeo HY, Shafie AA, Coudeville L, Steinberg LD, Gill BS, Jahis R
    Value Health, 2015 Nov;18(7):A582.
    PMID: 26533272 DOI: 10.1016/j.jval.2015.09.1949
  9. Fulltext Molecular Weight, Protein Binding Affinity and Methane Mitigation of Condensed Tannins from Mangosteen-peel (Garcinia mangostana L)
    Paengkoum P, Phonmun T, Liang JB, Huang XD, Tan HY, Jahromi MF
    Asian-Australas J Anim Sci, 2015 Oct;28(10):1442-8.
    PMID: 26323400 DOI: 10.5713/ajas.13.0834
    The objectives of this study were to determine the molecular weight of condensed tannins (CT) extracted from mangosteen (Garcinia mangostana L) peel, its protein binding affinity and effects on fermentation parameters including total gas, methane (CH4) and volatile fatty acids (VFA) production. The average molecular weight (Mw) of the purified CT was 2,081 Da with a protein binding affinity of 0.69 (the amount needed to bind half the maximum bovine serum albumin). In vitro gas production declined by 0.409, 0.121, and 0.311, respectively, while CH4 production decreased by 0.211, 0.353, and 0.549, respectively, with addition of 10, 20, and 30 mg CT/500 mg dry matter (DM) compared to the control (p<0.05). The effects of CT from mangosteen-peel on in vitro DM degradability (IVDMD) and in vitro N degradability was negative and linear (p<0.01). Total VFA, concentrations of acetic, propionic, butyric and isovaleric acids decreased linearly with increasing amount of CT. The aforementioned results show that protein binding affinity of CT from mangosteen-peel is lower than those reported for Leucaena forages, however, the former has stronger negative effect on IVDMD. Therefore, the use of mangosteen-peel as protein source and CH4 mitigating agent in ruminant feed requires further investigations.
  10. Improved high performance liquid chromatographic analysis of omeprazole in human plasma
    Yuen KH, Choy WP, Tan HY, Wong JW, Yap SP
    J Pharm Biomed Anal, 2001 Feb;24(4):715-9.
    PMID: 11272330
    A simple high-performance liquid chromatographic method was developed for the determination of omeprazole in human plasma. Omeprazole and the internal standard, chloramphenicol, were extracted from alkalinized plasma samples using dichloromethane. The mobile phase was 0.05 M Na2HPO4-ACN (65:35, v/v) adjusted to pH 6.5. Analysis was run at a flow rate of 1.0 ml/min at a detection wavelength of 302 nm. The method was specific and sensitive with a detection limit of 2.5 ng/ml at a signal-to-noise ratio of 4:1. The limit of quantification was set at 5 ng/ml. The calibration curve was linear over a concentration range of 5-1280 ng/ml. Mean recovery value of the extraction procedure was about 96%, while the within and between day coefficient of variation and percent error values of the assay method were all less than 14%.
  11. Appraisal of latex glove proteins in the induction of sensitivity to multiple latex allergens
    Yeang HY, Chow KS, Yusof F, Arif SA, Chew NP, Loke YH
    J Investig Allergol Clin Immunol, 2000 Jul-Aug;10(4):215-22.
    PMID: 11039838
    Six Hevea brasiliensis latex protein allergens, Hevb 1, Hev b 2, Hev b 3, Hev b 4, and two variants of Hev b 7 (7b and 7c), were purified from Hevea latex, while a seventh protein, Hev b 5, was prepared in recombinant form. The presence of these proteins in glove extracts was indicated by their respective antibodies in the serum of rabbits immunized against the extracts. The relative propensities of IgE binding to the individual latex allergens were compared using sera from latex-allergic patients. IgE recognition of Hev b 4, Hev b 7b, Hev b 5 and Hev b 2 was most frequently encountered, with 75, 61, 31 and 28%, respectively, of the patient sera reacting. Sensitivity to multiple latex proteins was common, and out of the 31 seropositive patients, 23 (74%/ ) had IgE against at least two latex allergens, while 12 (39%) had IgE specific for at least three allergens. Statistical analysis of the data suggested that many patients might have acquired sensitivity to Hev b 2, Hev b 4 and Hev b 7b from a common source. (e.g., from latex products). On the other hand, sensitivity to Hev b 5 and to Hev b 7c were interrelated. It is plausible that sensitivity to these two proteins might have been acquired from sources other than latex products (e.g., from certain foods).
  12. Amino acid sequence similarity of Hev b 3 to two previously reported 27- and 23-kDa latex proteins allergenic to spina bifida patients
    Yeang HY, Ward MA, Zamri AS, Dennis MS, Light DR
    Allergy, 1998 May;53(5):513-9.
    PMID: 9636811
    Separate studies have reported spina bifida patients to be especially allergic to proteins of 27 and 23 kDa found in the serum of centrifuged natural rubber latex. An insoluble latex protein located on the surface of small rubber particles, Hev b 3, has similarly been found to be allergenic to spina bifida patients. In this study, internal amino acid sequences of Hev b 3 showed similarity to the published sequences for the 27- and 23-kDa latex proteins. The latter allergens are hence identified as Hev b 3. Determination of the molecular weight of Hev b 3 revealed various species of 22-23 kDa. The consistent gaps of about 266 Da observed between various forms of the intact protein suggest that the protein undergoes post-translational modification. To determine whether Hev b 3 also occurs in a soluble form in the latex serum, its presence in molecular-filtered serum was checked by ELISA and Western blot. The results showed Hev b 3 to be largely absent in the C-serum from fresh latex. The protein is therefore insoluble in its native state. However, a small amount of the solubilized protein was detected in ammonia-stabilized latex (commonly used in the manufacture of latex products).
  13. The 14.6 kd rubber elongation factor (Hev b 1) and 24 kd (Hev b 3) rubber particle proteins are recognized by IgE from patients with spina bifida and latex allergy
    Yeang HY, Cheong KF, Sunderasan E, Hamzah S, Chew NP, Hamid S, et al.
    J Allergy Clin Immunol, 1996 Sep;98(3):628-39.
    PMID: 8828541 DOI: 10.1016/s0091-6749(96)70097-0
    Two major water-insoluble proteins are located on the surface of rubber particles in Hevea brasiliensis latex. A 14.6 kd protein (Hev b 1), found mainly on large rubber particles (> 350 mm in diameter), and a 24 kd protein (Hev b 3), found mainly on small rubber particles (average diameter, 70 nm), are recognized by IgE from patients with spina bifida and latex allergy. Although Hev b 1 (also called the rubber elongation factor [REF]) has previously been reported as a major latex allergen, this conclusion has been disputed on the basis of results from other studies. The allergenicity of Hev b 1 is verified in this study by testing the recombinant protein generated from its gene. Because allergenicity is confined to patients with spina bifida and not observed in adults sensitive to latex, it is not a major latex allergen. The identification of Hev b 3 as another allergen originating from rubber particles is confirmed by immunogold labeling and electron microscopy. Observations with the monoclonal antibody USM/RC2 developed against Hev b 3 show that the protein has a tendency to fragment into several polypeptides of lower molecular weight (from 24 kd to about 5 kd) when stored at -20 degrees C. There is also indication of protein aggregation from the appearance of proteins with molecular weights greater than 24 kd. Fragmentation of Hev b 3 is induced immediately on he addition of latex B-serum, which is normally compartmentalized in the lutoids in fresh latex. In the preparation of ammoniated latex (used for the manufacture of latex products), the lutoids are ruptured, and the released B-serum reacts with Hev b 3 on the rubber particles to give rise to an array of low molecular weight polypeptides that are allergenic to patients with spina bifida.
  14. Prevalence and ethnic differences of autosomal-dominant cerebellar ataxia in Singapore
    Zhao Y, Tan EK, Law HY, Yoon CS, Wong MC, Ng I
    Clin Genet, 2002 Dec;62(6):478-81.
    PMID: 12485197
    We report the prevalence and ethnic differences of autosomal-dominant cerebellar ataxia (ADCA) in Singapore. Amongst 204 patients with ataxia who underwent genetic testing for dentatorubral-pallidoluysian atrophy (DRPLA) and for spinocerebellar ataxias (SCA) 1, 2, 3, 6, 7, 8, 10 and 12, 58 (28.4%) patients from 36 families tested positive. SCA 3 was identified in 31 (53.4%) patients from 15 families, SCA 2 in 17 (29.3%) patients from 12 families and SCA 1 in four (6.9%) patients from four families. Other SCA subtypes were rare. SCA 2 was the only subtype identified amongst ethnic Malay and ethnic Indian families. The estimated prevalence of ADCA in Singaporean families was at least 1 : 27,000. Based on the history and ancestry of Singaporeans, our study supported a founder effect for specific SCA subtypes and the association of ethnicity-specific SCA subtypes. Our findings suggest that SCA 2 is relatively common amongst the Malay race and that priority testing for SCA 3 and SCA 2 for ethnic Chinese, and SCA 2 for ethnic Malay, may be cost effective and relevant for the region.
  15. Molecular cloning and immunoglobulin E reactivity of a natural rubber latex lecithinase homologue, the major allergenic component of Hev b 4
    Sunderasan E, Bahari A, Arif SA, Zainal Z, Hamilton RG, Yeang HY
    Clin Exp Allergy, 2005 Nov;35(11):1490-5.
    PMID: 16297147 DOI: 10.1111/j.1365-2222.2005.02371.x
    BACKGROUND:
    Hev b 4 is an allergenic natural rubber latex (NRL) protein complex that is reactive in skin prick tests and in vitro immunoassays. On SDS-polyacrylamide gel electrophoresis (SDS-PAGE), Hev b 4 is discerned predominantly at 53-55 kDa together with a 57 kDa minor component previously identified as a cyanogenic glucosidase. Of the 13 NRL allergens recognized by the International Union of Immunological Societies, the 53-55 kDa Hev b 4 major protein is the only candidate that lacks complete cDNA and protein sequence information.

    OBJECTIVE:
    We sought to clone the transcript encoding the Hev b 4 major protein, and characterize the native protein and its recombinant form in relation to IgE binding.

    METHODS:
    The 5'/3' rapid amplification of cDNA ends method was employed to obtain the complete cDNA of the Hev b 4 major protein. A recombinant form of the protein was over-expressed in Escherichia coli. The native Hev b 4 major protein was deglycosylated by trifluoromethane sulphonic acid. Western immunoblots of the native, deglycosylated and recombinant proteins were performed using both polyclonal antibodies and sera from latex-allergic patients.

    RESULTS:
    The cDNA encoding the Hev b 4 major protein was cloned. Its open reading frame matched lecithinases in the conserved domain database and contained 10 predicted glycosylation sites. Detection of glycans on the Hev b 4 lecithinase homologue confirmed it to be a glycoprotein. The deglycosylated lecithinase homologue was discerned at 40 kDa on SDS-PAGE, this being comparable to the 38.53 kDa mass predicted by its cDNA. Deglycosylation of the lecithinase homologue resulted in the loss of IgE recognition, although reactivity to polyclonal rabbit anti-Hev b 4 was retained. IgE from latex-allergic patients also failed to recognize the non-glycosylated E. coli recombinant lecithinase homologue.

    CONCLUSION:
    The IgE epitopes of the Hev b 4 lecithinase homologue reside mainly in its carbohydrate moiety, which also account for the discrepancy between the observed molecular weight of the protein and the value calculated from its cDNA.
  16. Cloning, expression, and characterization of recombinant Hev b 3, a Hevea brasiliensis protein associated with latex allergy in patients with spina bifida
    Wagner B, Krebitz M, Buck D, Niggemann B, Yeang HY, Han KH, et al.
    J Allergy Clin Immunol, 1999 Nov;104(5):1084-92.
    PMID: 10550757
    BACKGROUND: Two natural rubber latex proteins, Hev b 1 and Hev b 3, have been described in spina bifida (SB)-associated latex allergy.

    OBJECTIVE: The aim of this study was to clone and express Hev b 3 and to obtain the immunologic active and soluble recombinant allergen for diagnosis of SB-associated latex allergy.

    METHODS: A complementary DNA (cDNA) coding for Hev b 3 was amplified from RNA of fresh latex collected from Malaysian rubber trees (Hevea brasiliensis). PCR primers were designed according to sequences of internal peptide fragments of natural (n) Hev b 3. The 5'-end sequence was obtained by specific amplification of cDNA ends. The recombinant (r) Hev b 3 was produced in Escherichia coli as a 6xHis tagged protein. Immunoblotting and inhibition assays were performed to characterize the recombinant allergen.

    RESULTS: An Hev b 3 cDNA clone of 922 bp encoding a protein of 204 amino acid residues corresponding to a molecular weight of 22.3 kd was obtained. In immunoblots 29/35, latex-allergic patients with SB revealed IgE binding to rHev b 3, as did 4 of 15 of the latex-sensitized group. The presence of all IgE epitopes on rHev b 3 was shown by its ability to abolish all IgE binding to nHev b 3. Hev b 3 is related to Hev b 1 by a sequence identity of 47%. Cross-reactivity between these 2 latex allergens was illustrated by the large extent of inhibition of IgE binding to nHev b 1 by rHev b 3.

    CONCLUSION: rHev b 3 constitutes a suitable in vitro reagent for the diagnosis of latex allergy in patients with SB. The determination of the full sequence of Hev b 3 and the production of the recombinant allergen will allow the epitope mapping and improve diagnostic reagents for latex allergy.

  17. Identification of enterovirus 71 isolates from an outbreak of hand, foot and mouth disease (HFMD) with fatal cases of encephalomyelitis in Malaysia
    AbuBakar S, Chee HY, Al-Kobaisi MF, Xiaoshan J, Chua KB, Lam SK
    Virus Res, 1999 May;61(1):1-9.
    PMID: 10426204
    Thirteen enterovirus 71 (EV71) isolates were obtained from both fatal and non-fatal infections of patients seen in Peninsula Malaysia and in Sarawak during an outbreak of hand, foot and mouth disease (HFMD) in Malaysia in 1997, with incidences of fatal brainstem encephalomyelitis. The isolates were identified using immunofluorescence staining, neutralization assays, and partial sequencing of the 5' untranslated regions (UTR). Assessment of the potential genetic relationships of the isolates using the partial 5'UTR sequences suggested clustering of the isolates into at least two main clusters. Isolates from Peninsula Malaysia were found in both clusters whereas Sarawak-derived isolates clustered only in cluster II. Isolates derived from fatal infections, however, occurred in both clusters and no distinctive nucleotide sequences could be attributed to the fatal isolates. Examination of the nucleotide sequences revealed at least 13 nucleotide positions in all the isolates which differ completely from the previously reported EV71 5'UTR sequences. In addition, at least 11 nucleotide position differences within the 5'UTR were noted which differentiated cluster I from cluster II. Predicted secondary RNA structures drawn using the nucleotide sequences also suggested differences between isolates from the two clusters. These findings suggest the presence of at least two potentially virulent EV71 co-circulating in Malaysia during the 1997 HFMD outbreak.
  18. Application of a multi-faceted approach for the assessment of treatment response in falciparum malaria: a study from Malaysian Borneo
    Cox-Singh J, Lu HY, Davis TM, Ilett KF, Hackett LP, Matusop A, et al.
    Int J Parasitol, 2003 Nov;33(13):1545-52.
    PMID: 14572517
    Thirty-two patients reporting to the Lundu District Hospital, Sarawak, Malaysian Borneo, with uncomplicated falciparum malaria were recruited into a multifaceted study to assess treatment response. Following combined chloroquine and sulphadoxine/pyrimethamine treatment the patients were followed for 28 days according to the World Health Organisation in vivo drug response protocol. The in vivo study revealed that 13 (41%) of the patients had a sensitive response to treatment, five (16%) cleared asexual stage parasites but had persistent gametocytes, 11 (34%) had RI type resistance and three (9%) had RII type resistance requiring quinine intervention before day 7 for parasite clearance. Although clinically insignificant, patients with persistent gametocytes, surviving chloroquine and sulphadoxine/pyrimethamine treatment during maturation, were placed in the reduced response to treatment group for analysis. Allelic typing detected 100% prevalence of the pfcrt K76T marker associated with chloroquine resistance and 78% prevalence of the pfdhfr NRNL haplotype associated with sulphadoxine/pyrimethamine treatment failure. High serum chloroquine levels and pfdhfr haplotypes with
  19. Sensitivity of the nested-polymerase chain reaction (PCR) assay for Brugia malayi and significance of 'free' DNA in PCR-based assays
    Cox-Singh J, Pomrehn AS, Wolfe ND, Rahman HA, Lu HY, Singh B
    Int J Parasitol, 2000 Oct;30(11):1177-9.
    PMID: 11027784
    The blood filtration method was used as the gold standard to determine the detection level of simple blood-spot sampling and nested-polymerase chain reaction (PCR) for Brugia malayi. Of 100 samples, 48 were filtration-positive. Of these, 26 had microfilaria counts that were low enough (<1-29 microfilariae/ml) to accurately assess the limit of detection by nested-PCR. Nested-PCR consistently detected B. malayi DNA in samples with > or = 10 microfilariae/ml. Post-filtration, microfilaria-depleted, blood-spots from microfilaria-positive samples were screened by nested-PCR and B. malayi specific 'free' DNA was detected in 51.7% of these samples. There was no evidence for 'free' DNA in microfilaria-negative individuals from this endemic community.
  20. Associations between psychological factors and accelerometer-measured physical activity in urban Asian adults
    Müller AM, Tan CS, Chu AHY, van Dam RM, Müller-Riemenschneider F
    Int J Public Health, 2019 Jun;64(5):659-668.
    PMID: 30739208 DOI: 10.1007/s00038-019-01203-6
    OBJECTIVES: Examine the association between psychological variables and accelerometer-measured moderate-to-vigorous physical activity (MVPA) in urban Asians.

    METHODS: A population-based cross-sectional study was conducted in Singapore. Participants wore an accelerometer for 7 days to measure physical activity (PA). Demographic, anthropometric and psychological data were also collected. Psychological variables included PA guideline knowledge, motivational profile for PA self-regulation (5 subscales), perceived barriers to PA (4 subscales) and perceived social support for PA. Regression models with adjustment for socio-demographic variables were fitted.

    RESULTS: External regulation (b = - 13.03, 95% CI - 34.55; - 1.50) and perceived daily life barriers (b = - 12.63, 95% CI - 24.95; - 0.32) were significantly associated with fewer weekly MVPA minutes. A significant interaction between perceived social support and age (p = 0.046) was found. Social support was significantly negative associated with MVPA minutes in younger (

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