Leslie Thian Lung Than
Universiti Putra Malaysia
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Leslie Thian Lung Than.
PLOS ONE | 2015
Fang Lee Lim; Leslie Thian Lung Than; Salmiah Md Said; Jamal Hisham Hashim; Dan Norbäck
A prevalence study was conducted among office workers in Malaysia (N= 695). The aim of this study was to examine associations between asthma, airway symptoms, rhinitis and house dust mites (HDM) and cat allergy and HDM levels in office dust. Medical data was collected by a questionnaire. Skin prick tests were performed for HDM allergens (Dermatophagoides pteronyssinus, Dermatophagoides farinae) and cat allergen Felis domesticus. Indoor temperature and relative air humidity (RH) were measured in the offices and vacuumed dust samples were analyzed for HDM allergens. The prevalence of D. pteronyssinus, D. farinae and cat allergy were 50.3%, 49.0% and 25.5% respectively. Totally 9.6% had doctor-diagnosed asthma, 15.5% had current wheeze and 53.0% had current rhinitis. The Der p 1 (from D. pteronyssinus) and Der f 1 (from D. farinae) allergens levels in dust were 556 ng/g and 658 ng/g respectively. Statistical analysis was conducted by multilevel logistic regression, adjusting for age, gender, current smoking, HDM or cat allergy, home dampness and recent indoor painting at home. Office workers with HDM allergy had more wheeze (p= 0.035), any airway symptoms (p= 0.032), doctor-diagnosed asthma (p= 0.005), current asthma (p= 0.007), current rhinitis (p= 0.021) and rhinoconjuctivitis (p< 0.001). Cat allergy was associated with wheeze (p= 0.021), wheeze when not having a cold (p= 0.033), any airway symptoms (p= 0.034), doctor-diagnosed asthma (p= 0.010), current asthma (p= 0.020) and nasal allergy medication (p= 0.042). Der f 1 level in dust was associated with daytime breathlessness (p= 0.033) especially among those with HDM allergy. Der f 1 levels were correlated with indoor temperature (p< 0.001) and inversely correlated with RH (p< 0.001). In conclusion, HDM and cat allergies were common and independently associated with asthma, airway symptoms and rhinitis. Der f 1 allergen can be a risk factor for daytime breathlessness.
Journal of Applied Microbiology | 2015
Shu Yih Chew; Yoke Kqueen Cheah; Heng Fong Seow; Doblin Sandai; Leslie Thian Lung Than
This study investigates the antagonistic effects of the probiotic strains Lactobacillus rhamnosus GR‐1 and Lactobacillus reuteri RC‐14 against vulvovaginal candidiasis (VVC)‐causing Candida glabrata.
Mycoses | 2016
Shu Yih Chew; Leslie Thian Lung Than
Vulvovaginal candidosis (VVC) is a common gynaecological disorder that is delineated by the inflammation of vaginal wall and it is caused by the opportunistic fungal pathogen Candida species. In fact, three out of every four women will experience at least one occasion of VVC during some point in their lives. Although uncomplicated VVC is relatively harmless, the complicated VVC such as recurrent attack often creates restlessness and depression in the patients, thus greatly affects their quality of life. Managements of VVC are usually associated with the use of antimycotic suppositories, topical cream or oral agents. These antimycotic agents are either available over‐the‐counter or prescribed by the clinicians. In recent decades, the rise of clinical challenges such as the increased prevalence of resistant Candida strains, recurrent VVC infection and adverse effects of multidrug interactions have necessitated the development of novel therapeutic or prophylactic options to combat the complicated VVC in the future. In this review, we discuss the current antimycotic treatments available for Candida vaginitis and the problems that exist in these seemingly effective treatments. Besides, we attempt to contemplate some of the future and prospective strategies surrounding the development of alternative therapeutic and prophylactic options in treating and preventing complicated VVC respectively.
Journal of Experimental Nanoscience | 2016
Sarva Mangala Praveena; Lim Suk Han; Leslie Thian Lung Than; Ahmad Zaharin Aris
ABSTRACT This study investigates the ability of cellulose filter paper coated with silver nanoparticles to remove Escherichia coli from drinking water. The cellulose filter paper was coated with silver nanoparticles by a chemical reduction method using two different ratios of sodium borohydride and silver nitrate. In consideration of drinking-water quality standards and non-carcinogenic health risks, the optimum sodium borohydride:silver nitrate ratio for coating the cellulose filter paper was determined by comparing the silver in the effluent after E. coli removal. For both ratios, 100% E. coli removal was realised. In terms of the silver in the effluent, only the first two lowest concentrations for both ratios of sodium borohydride and silver nitrate were compliant with the drinking-water quality standards, demonstrating hazard quotients (HQs) between 0.084 and 0.484. On the basis of the highest level of E. coli removal with the lowest HQ value, the optimum sodium borohydride:silver nitrate ratio for coating the cellulose filter paper as an antibacterial water filter was 2:1 molar ratio (0.002 M:0.001 M). Silver nanoparticle-coated cellulose filter paper was found to be an inexpensive and easy-to-use emergency antibacterial water filter to generate clean drinking water.
Science of The Total Environment | 2015
Fang Lee Lim; Salmiah Md Said; Leslie Thian Lung Than; Jamal Hisham Hashim; Dan Norbäck
There are few studies on sick building syndrome (SBS) including clinical measurements for atopy and fractional exhaled nitric oxide (FeNO). Our aim was to study associations between SBS symptoms, selected personal factors, office characteristics and indoor office exposures among office workers from a university in Malaysia. Health data were collected by a questionnaire (n=695), skin prick test (SPT) (n=463) and FeNO test (n=460). Office settled dust was vacuumed and analyzed for endotoxin, (1,3)-β-glucan and house dust mites (HDM) allergens group 1 namely Dermatophagoides pteronyssinus (Der p 1) and Dermatophagoides farinae (Der f 1). Office indoor temperature, relative air humidity (RH), carbon monoxide (CO) and carbon dioxide (CO2) were measured by a direct reading instrument. Associations were studied by two-levels multiple logistic regression with mutual adjustment and stratified analysis. The prevalence of weekly dermal, mucosal and general symptoms was 11.9%, 16.0% and 23.0% respectively. A combination of SPT positivity (allergy to HDM or cat) and high FeNO level (≥25 ppb) was associated with dermal (p=0.002), mucosal (p<0.001) and general symptoms (p=0.05). Der f1 level in dust was associated with dermal (p<0.001), mucosal (p<0.001) and general (p=0.02) symptoms. Among those with allergy to D. farinae, associations were found between Der f 1 levels in dust and dermal (p=0.003), mucosal (p=0.001) and general symptoms (p=0.007). Office-related symptoms were associated with Der f 1 levels in dust (p=0.02), low relative air humidity (p=0.04) and high office temperature (p=0.05). In conclusion, a combination of allergy to cat or HDM and high FeNO is a risk factor for SBS symptoms. Der f 1 allergen in dust can be a risk factor for SBS in the office environment, particularly among those sensitized to Der f 1 allergen.
Infection, Genetics and Evolution | 2016
Tzu Shan Ng; Mohd Nasir Mohd Desa; Doblin Sandai; Pei Pei Chong; Leslie Thian Lung Than
Glucose is an important fuel source to support many living organisms. Its importance in the physiological fitness and pathogenicity of Candida glabrata, an emerging human fungal pathogen has not been extensively studied. The present study aimed to investigate the effects of glucose on the growth, biofilm formation, antifungal susceptibility and oxidative stress resistance of C. glabrata. In addition, its effect on the expression of a putative high affinity glucose sensor gene, SNF3 was also investigated. Glucose concentrations were found to exert effects on the physiological responses of C. glabrata. The growth rate of the species correlated positively to the amount of glucose. In addition, low glucose environments were found to induce C. glabrata to form biofilm and resist amphotericin B. Conversely, high glucose environments promoted oxidative stress resistance of C. glabrata. The expression of CgSNF3 was found to be significantly up-regulated in low glucose environments. The expression of SNF3 gene in clinical isolates was found to be higher compared to ATCC laboratory strains in low glucose concentrations, which may explain the better survivability of clinical isolates in the low glucose environment. These observations demonstrated the impact of glucose in directing the physiology and virulence fitness of C. glabrata through the possible modulation by SNF3 as a glucose sensor, which in turn aids the species to adapt, survive and thrive in hostile host environment.
Diagnostic Microbiology and Infectious Disease | 2012
Leslie Thian Lung Than; Pei Pei Chong; Kee Peng Ng; Heng Fong Seow
A seminested PCR detecting ten medically important Candida species were achieved. Analytical sensitivity and specificity were not compromised.
Jundishapur Journal of Microbiology | 2016
Oluwaseun Ayodeji Ishola; Seng Yeat Ting; Yasser M. Tabana; Mowaffaq Adam Ahmed; Muhammad Amir Yunus; Rafeezul Mohamed; Leslie Thian Lung Than; Doblin Sandai
Background A major characteristic of Candida biofilm cells that differentiates them from free-floating cells is their high tolerance to antifungal drugs. This high resistance is attributed to particular biofilm properties, including the accumulation of extrapolymeric substances, morphogenetic switching, and metabolic flexibility. Objectives This study evaluated the roles of metabolic processes (in particular the glyoxylate cycle) on biofilm formation, antifungal drug resistance, morphology, and cell wall components. Methods Growth, adhesion, biofilm formation, and cell wall carbohydrate composition were quantified for isogenic Candida albicans ICL1/ICL1, ICL1/icl1, and icl1/icl1 strains. The morphology and topography of these strains were compared by light microscopy and scanning electron microscopy. FKS1 (glucan synthase), ERG11 (14-α-demethylase), and CDR2 (efflux pump) mRNA levels were quantified using qRT-PCR. Results The ICL1/icl1 and icl1/icl1 strains formed similar biofilms and exhibited analogous drug-tolerance levels to the control ICL1/ICL1 strains. Furthermore, the drug sequestration ability of β-1, 3-glucan, a major carbohydrate component of the extracellular matrix, was not impaired. However, the inactivation of ICL1 did impair morphogenesis. ICL1 deletion also had a considerable effect on the expression of the FKS1, ERG11, and CDR2 genes. FKS1 and ERG11 were upregulated in ICL1/icl1 and icl1/icl1 cells throughout the biofilm developmental stages, and CDR2 was upregulated at the early phase. However, their expression was downregulated compared to the control ICL1/ICL1 strain. Conclusions We conclude that the glyoxylate cycle is not a specific determinant of biofilm drug resistance.
Jundishapur Journal of Microbiology | 2015
Tzu Shan Ng; Mohd Nasir Mohd Desa; Doblin Sandai; Pei Pei Chong; Leslie Thian Lung Than
Background: The sensing mechanism of glucose in Saccharomyces cerevisiae is well studied. However, such information is scarcely found in other yeast species such as Candida glabrata. Objectives: This study aimed to identify the glucose sensing pathway related genes of C. glabrata and to analyze the regulation pattern of these genes in response to different surrounding glucose concentrations through the quantitative real time polymerase chain reaction (qRT-PCR). Materials and Methods: Phylogenetic analysis was carried out on predicted amino acid sequences of C. glabrata and S. cerevisiae to compare their degree of similarity. In addition, the growth of C. glabrata in response to different amounts of glucose (0%, 0.01%, 0.1%, 1% and 2%) was evaluated via the spot dilution assay on prepared agar medium. Besides, the SNF3 and RGT2, which act as putative glucose sensors, and the RGT1 and MIG1, which act as putative transcriptional regulators and selected downstream hexose transporters (HXTs), were analysed through qRT-PCR analysis for the gene expression level under different glucose concentrations. Results: Comparative analysis of predicted amino acids in the phylogenetic tree showed high similarity between C. glabrata and S cerevisiae. Besides, C. glabrata demonstrated the capability to grow in glucose levels as low as 0.01% in the spot dilution assay. In qRT-PCR analysis, differential expressions were observed in selected genes when C. glabrata was subjected to different glucose concentrations. Conclusions: The constructed phylogenetic tree suggests the close evolutionary relationship between C. glabrata and S. cerevisiae. The capability of C. glabrata to grow in extremely low glucose environments and the differential expression of selected glucose-sensing related genes suggested the possible role of these genes in modulating the growth of C. glabrata in response to different glucose concentrations. This study helps deepen our understanding of the glucose sensing mechanism in C. glabrata and serves to provide fundamental data that may assist in unveiling this mechanism as a potential drug target.
Journal of Asthma | 2016
Fang Lee Lim; Salmiah Md Said; Leslie Thian Lung Than; Jamal Hisham Hashim; Dan Norbäck
Abstract Objective: There are few studies on fractional exhaled nitric oxide (FeNO) and respiratory symptoms among adults in tropical areas. The aim was to study associations between FeNO and selected personal factors, respiratory symptoms, allergies, office characteristics and indoor office exposures among office workers (n = 460) from a university in Malaysia. Methods: Information on health was collected by a questionnaire, skin prick test and FeNO measurement. Temperature, relative air humidity, carbon monoxide and carbon dioxide were measured in the offices. Settled dust was vacuumed in the offices and analyzed for endotoxin, (1,3)-β-glucan and house dust mites allergens, namely Dermatophagoides pteronyssinus (Der p 1) and Dermatophagoides farinae (Der f 1). Two-level linear mixed models and multiple logistic regression were used to analyze the associations. Results: One-fourth (25.9%) of the office workers had elevated FeNO level (≥25 ppb) and 61.5% had HDM, cat, seafood or pollen allergy. Male gender (p < 0.001), current smoking (p = 0.037), height (p < 0.001) and atopy (p < 0.001) were associated with FeNO. The amount of vacuumed dust was associated with FeNO among atopic subjects (p = 0.009). Asthma and rhinitis symptoms were associated with FeNO (p < 0.05), especially among atopic subjects. In particular, a combination of atopy and elevated FeNO were associated with doctor-diagnosed asthma (p < 0.001), rhinitis (p < 0.001) and airway symptoms last 12 months (p < 0.001). Conclusion: Gender, smoking, height and atopy are important risk factors for elevated FeNO levels. A combination of allergy testing and FeNO measurement could be useful in respiratory illness epidemiology studies and patient investigations in tropical areas.