41 results on '"Cheah, Y. K."'
Search Results
2. Transcriptomics analysis provides insights into the heat adaptation strategies of an Antarctic bacterium, Cryobacterium sp. SO1
- Author
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Teoh, C. P., Lavin, P., Yusof, N. A., González-Aravena, M., Najimudin, N., Cheah, Y. K., and Wong, C. M. V. L.
- Published
- 2023
- Full Text
- View/download PDF
3. Genomics and transcriptomics analyses provide insights into the cold adaptation strategies of an Antarctic bacterium, Cryobacterium sp. SO1
- Author
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Teoh, C. P., Lavin, P., Lee, D. J. H., González-Aravena, M., Najimudin, N., Lee, P. C., Cheah, Y. K., and Wong, C. M. V. L.
- Published
- 2021
- Full Text
- View/download PDF
4. Genome sequences of two cold-adapted Cryobacterium spp. SO1 and SO2 from Fildes Peninsula, Antarctica
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Teoh, C. P., Wong, C. M. V. L., Lee, D. J. H., González, M. A., Najimudin, N., Lee, P. C., and Cheah, Y. K.
- Published
- 2018
5. Analysis of bacterial communities of King George and Deception Islands, Antarctica using high-throughput sequencing
- Author
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Chua, C. Y., Yong, S. T., González, M. A., Lavin, P., Cheah, Y. K., Tan, G. Y. A., and Wong, C. M. V. L.
- Published
- 2018
6. Probiotic Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 exhibit strong antifungal effects against vulvovaginal candidiasis-causing Candida glabrata isolates
- Author
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Chew, S. Y., Cheah, Y. K., Seow, H. F., Sandai, D., and Than, L. T.L.
- Published
- 2015
- Full Text
- View/download PDF
7. EPIDERMAL GROWTH FACTOR RECEPTOR MUTATIONS IN LUNG ADENOCARCINOMA IN A MULTIETHNIC POPULATION: 317
- Author
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LIAM, C K, WAHID, MI A., RAJADURAI, P, CHEAH, Y K, and NG, T SY
- Published
- 2012
8. Prevalence of Staphylococcus aureus carriage by young Malaysian footballers during indoor training
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William, J L, Radu, S, Aziz, S A, Rahim, R A, Cheah, Y K, Liwan, A, and Lihan, S
- Published
- 2004
9. Antimicrobial susceptibilities and random amplified polymorphic DNA-PCR fingerprint characterization of Candida glabrata, Candida parapsilosis and Candida rugosa from two major hospitals in Kuala Lumpur, Malaysia.
- Author
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Madhavan, P., Chong, P. P., Farida, J., Fauziah, O., Cheah, Y. K., Arunkumar Karunanidhi, A., and Ng, K. P.
- Published
- 2019
10. Loop mediated isothermal amplification; a review on its application and strategy in animal species authentication of meat based food products.
- Author
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Tasrip, N. A., Khairil Mokhtar, N. F., Hanapi, U. K., Abdul Manaf, Y. N., Ali, M. E., Cheah, Y. K., Mustafa, S., and Mohd Desa, M. N.
- Subjects
DNA primers ,ANIMAL species ,GENE amplification ,NUCLEIC acid amplification techniques ,GENTIAN violet ,MEAT ,NUCLEOTIDE sequence - Abstract
Isothermal amplification is a technique that can amplify target DNA sequences at a single incubation temperature. Loop-mediated isothermal amplification (LAMP) is an extension of the isothermal DNA amplification technique that combines rapidity, simplicity, high specificity and sensitivity. Due to its overwhelming characteristics, LAMP has been explored for its feasibility in detecting various subjects, and recently in meat-based food products for DNA-based meat species authentication. It has been developed to target various meat species such as porcine, chicken, horse, and ostrich with sensitivity as low as 0.1 pg/μL. Further improvement with the use of magnetic beads, electrochemiluminescence and special dye such as calcein and crystal violet had increased the sensitivity of the LAMP assay. Other important characteristics were specific target gene primers as well as a shorter incubation time, warranting a good prospect for rapid testing authentication. [ABSTRACT FROM AUTHOR]
- Published
- 2019
11. Validity of self-reported weight and height: a cross-sectional study among Malaysian adolescents.
- Author
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Kee, C. C., Lim, K. H., Sumarni, M. G., Teh, C. H., Chan, Y. Y., Nuur Hafizah, M. I., Cheah, Y. K., Tee, E. O., Faudzi, Y. Ahmad, Nasir, M. Amal, Ahmad Faudzi, Y, and Amal Nasir, M
- Subjects
BODY mass index ,ADOLESCENT health ,SCHOOL children ,EPIDEMIOLOGY ,NUTRITIONAL status ,ANTHROPOMETRY ,BODY weight ,RESEARCH evaluation ,RURAL population ,SELF-evaluation ,STATURE ,CITY dwellers ,ACQUISITION of data ,CROSS-sectional method ,STANDARDS - Abstract
Background: Self-reported weight and height are commonly used in lieu of direct measurements of weight and height in large epidemiological surveys due to inevitable constraints such as budget and human resource. However, the validity of self-reported weight and height, particularly among adolescents, needs to be verified as misreporting could lead to misclassification of body mass index and therefore overestimation or underestimation of the burden of BMI-related diseases. The objective of this study was to determine the validity of self-reported weight and height among Malaysian secondary school children.Methods: Both self-reported and directly measured weight and height of a subgroup of 663 apparently healthy schoolchildren from the Malaysian Adolescent Health Risk Behaviour (MyAHRB) survey 2013/2014 were analysed. Respondents were required to report their current body weight and height via a self-administrative questionnaire before they were measured by investigators. The validity of self-reported against directly measured weight and height was examined using intraclass correlation coefficient (ICC), the Bland-Altman plot and weighted Kappa statistics.Results: There was very good intraclass correlation between self-reported and directly measured weight [r = 0.96, 95% confidence interval (CI): 0.93, 0.97] and height (r = 0.94, 95% CI: 0.90, 0.96). In addition the Bland-Altman plots indicated that the mean difference between self-reported and direct measurement was relatively small. The mean difference (self-reported minus direct measurements) was, for boys: weight, -2.1 kg; height, -1.6 cm; BMI, -0.44 kg/m2 and girls: weight, -1.2 kg; height, -0.9 cm; BMI, -0.3 kg/m2. However, 95% limits of agreement were wide which indicated substantial discrepancies between self-reported and direct measurements method at the individual level. Nonetheless, the weighted Kappa statistics demonstrated a substantial agreement between BMI status categorised based on self-reported weight and height and the direct measurements (kappa = 0.76, 95% CI: 0.67, 0.84).Conclusion: Our results show that the self-reported weight and height were consistent with direct measurements and therefore can be used in assessing the nutritional status of Malaysian school children from the age of 13 to 17 years old in epidemiological studies and for surveillance purposes when direct measurements are not feasible, but not for assessing nutritional status at the individual level. [ABSTRACT FROM AUTHOR]- Published
- 2017
- Full Text
- View/download PDF
12. Factors affecting participation decision and amount of physical activity among urban dwellers in Malaysia.
- Author
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Cheah, Y. K., Azahadi, M., Phang, S. N., and Hazilah, N.
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PATIENT participation , *DECISION making , *EMPLOYMENT , *HEALTH behavior , *MARITAL status , *METROPOLITAN areas , *REGRESSION analysis , *SEX distribution , *SOCIOECONOMIC factors , *CROSS-sectional method , *PHYSICAL activity , *PSYCHOLOGY - Abstract
Objectives: The rapid rise in the prevalence of physical inactivity-related diseases has become a serious public health issue worldwide. The objective of the present study is to examine the factors affecting participation in physical activity among urban dwellers in Malaysia. Study design: This cross-sectional study measures physical activity using a rigorous regression model. Methods: Data are obtained from the National Health and Morbidity Survey 2011 (NHMS 2011). A lognormal hurdle model is used to analyse the participation decision and the amount decision of physical activity. Results: The results show that income, gender, ethnicity, marital status and employment status are significantly associated with participation decision and amount decision. However, age, insurance and self-rated health only affect participation decision, whereas family size, education and smoking only affect amount decision. Conclusions: It can, thus, be concluded that sociodemographic, insurance, lifestyle and health factors play an important role in determining physical activity behaviour among urban dwellers. When formulating policies, special attention must be paid to these factors. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
13. Applications of 18(F) FDG PET/CT in Oncology.
- Author
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Fathinul Fikri, A. S., Nordin, A. J., Cheah, Y. K., and Ahmad Saad, F. N.
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ONCOLOGY ,CANCER tomography ,POSITRON emission tomography ,FUTILE medical care ,MEDICAL imaging systems - Abstract
The escalating costs of conventional diagnostic technology in oncology have yet to obviate futile surgery intervention and the spiralling treatment cost. The evolution in engineering technology which looks at the correlation of the anatomy and the function of tumours i.e. Positron Emission Tomography-Computed Tomography (PET-CT) have impacted on the improved diagnostic accuracy and treatment in oncology. Clinical data have demonstrated that the information provided by PET/CT often changes patient management. This review addresses the value of PET-CT as a surrogate molecular marker in rumours and to discuss some issues in adopting PET/CT in routine daily practice as supported by the numbers of literature reviews of its application in oncology since it was first commercialized in 2001. The description of the technology used in multimodality imaging has gained encouraging interest among physicians, policy makers and insurance companies on the importance of the PET-CT, for which roles are not limited to the staging, disease prognostication and treatment monitoring with potential impact on treatment cost and justification of radiation safety for the patient. PET/CT is a useful tool in cancer investigation as evidenced by its role as a surrogate marker in underpinning the cellular reprogramming of different pathological entities. [ABSTRACT FROM AUTHOR]
- Published
- 2015
14. Molecular characterization of Escherichia coli isolated from different food sources.
- Author
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Cheah, Y. K., Tay, L. W., Aida, A. A., Son, R., Nakaguchi, T., and Nishibuchi, M.
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ESCHERICHIA coli ,WHEATEARS ,PLASMIDS ,ENTEROBACTERIACEAE ,POLYMERASE chain reaction ,MICROBIAL virulence - Abstract
Escherichia coli and Escherichia coli O157 were identified from "selom" (Oenanthe stolonifera), "pegaga" (Centella asiatica), beef, chicken, lamb, buffalo, "ulam Raja" (Cosmos caudatus) and "tenggek burung" (Euodia redlevi). The bacteria were recovered using chromagenic agar. Isolated Escherichia coli and Escherichia coli 0157 were further characterized by plasmid profiling and enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR). The virulence genes of the isolates (VT1, VT2, LT, ST, eaeA, inV) that produces pathogenic Escherichia coli and 16S rRNA gene were screened by a multiplex PCR assay. The plasmid profiling analysis showed that out of 176 isolates, only 103 isolates contained plasmids. ERIC-PCR analysis generated amplified products in the range of ~150 bp to > 1000 bp categorizing isolates into a total of 52 different profiles. Multiplex PCR showed that 20 (32.3%) of the isolates carried eaeA gene, 6 (9.7%) isolates possessed inV genes, only 1 (1.6%) have VT2 genes and 1 (1.6%) as well carried VT1 genes, 2 (3.2%) of the isolates harboured LT genes, and only 1 (1.6%) isolate possessed ST genes. There were no correlation between plasmid, ERIC-PCR and virulence genes profiles. [ABSTRACT FROM AUTHOR]
- Published
- 2015
15. Willingness-To-Pay for Monorail Services: Case Study in Penang, Malaysia.
- Author
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Lee, L. Y. and Cheah, Y. K.
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WILLINGNESS to pay ,MONORAIL railroads ,PUBLIC transit ,CROSS-sectional method ,TRANSPORTATION - Abstract
The main objective of this study is to examine the determinants of consumers' willingnessto- pay for monorail transportation in Penang (Malaysia). Cross sectional primary survey data with a total of 498 respondents is used for the analysis via a censored regression model. The results demonstrate that habit of recycling, experience in using urban rail-based transportation and problems of insufficient cark parks have the significant effects on the willingness-to-pay for a trip of monorail to travel to work. Whereas, age, gender, ethnicity, income, education and personal perspective on public transportation system are found to have no significant impact on the willingness-to-pay for a trip of monorail to travel to work. Based on these findings, several policies are recommended. [ABSTRACT FROM AUTHOR]
- Published
- 2014
16. Antibiogram Pattern among Cultures of Listeria monocytogenes Isolated from Frozen Burger Patties in Malaysia.
- Author
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Wong, W. C., Pui, C. F., Tunung, R., Ubong, A., Noor Hidayah, M. S., Farinazleen, M. G., Noorlis, A., Cheah, Y. K., and Son, R.
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LISTERIA monocytogenes ,DISEASE susceptibility ,ANTIBIOTICS ,SULFAMETHOXAZOLE ,TRIMETHOPRIM - Abstract
Forty-one isolates of Listeria monocytogenes, which were obtained from raw burger patties, were tested for their susceptibility against eleven antibiotics by using standard disc diffusion method. In particular, 31.7% of the isolates were found to be not resistant to any of the antibiotic tested while the rest showed resistance to at least one antibiotic. The result showed that resistance to tetracycline was the most common (46.3%), followed by erythromycin (36.6%), amikacin (31.7%), and sulfamethoxazole-trimethoprim (17.1%). All the isolates ofListeria monocytogenes were sensitive towards imipenem and gentamicin. The findings of the present study revealed the presence of multidrug-resistant Listeria monocytogenes isolates in the processed meat products and hence suggested the emergence of antibiotic resistance in bacterial strains in the food chain. [ABSTRACT FROM AUTHOR]
- Published
- 2012
17. Assessment of Noroviruses in selected Ulam from local market in Malaysia.
- Author
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Tuan Zainazor, T. C., Afsah-Hejri, L., Noor Hidayah, M. S., Noor Eliza, M. R., Naziehah, M. D., Tang, J. Y. H., Noorlis, A., Elexson, N., Chai, L. C., Ghazali, F. M., Cheah, Y. K., and Son, R.
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NOROVIRUSES ,HEAT treatment - Abstract
Presence of Norovirus in food can cause viral gasteroenteritis. Recently, lots of reports relating to Norovirus in food have been published. Special attention must be paid to the raw foods as they are not subjected to further heat treatment. In this study, pegaga, kesum, tauge and ulam raja (popular salad vegetables in Malaysia) were investigated for Norovirus. A total of 32 samples from each type of salad vegetables were purchased from local market and analyzed using One-step RTPCR (Reverse Transcriptase-Polymerase Chain Reaction) for both genogroups namely Norovirus Genogroup I and Genogroup II. Results showed that tauge had the highest contamination with Norovirus Genogroup I (15.6%) comparing to pegaga (9.4%), kesum (12.5%) and ulam raja (0%). Samples were free from Norovirus Genogroup II. The study showed that raw vegetables are high-risk foods and can be contaminated with Norovirus. [ABSTRACT FROM AUTHOR]
- Published
- 2012
18. Evaluation of injury to Saccharomyces rouxii YSa40 cells in low water activity/pH glycerol/CPB stress system.
- Author
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Yeoh, T. K., Cheah, Y. K., and Davies, R.
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SACCHAROMYCES ,FUNGI ,HYDROGEN-ion concentration ,GLYCERIN ,LACTIC acid - Abstract
Mid-exponential phase Saccharomyces rouxii YSa40 cells subsequently stressed at low a
w /pH in the 0.64 aw /pH 3.5 glycerol/CPB system became injured. Such injury was detected by the loss of ability of the stressed population to form colonies on secondary-stress plating medium (glycerol/BM agar at 0.94 aw /pH 3.5 (lactic acid)) while colony forming ability on secondary non-stress plating medium (sugars/BM agar at 0.94 aw /pH 3.5 (lactic) was unaffected. The injury was shown to be due to sensitivity to glycerol/lactic acid. Results of the present study will be useful for achieving complete decontamination of 'Intermediate Moisture Foods' against xerotolerant molds and yeast. [ABSTRACT FROM AUTHOR]- Published
- 2012
19. Influence of Socio-demographic Factors on Physical Activity Participation in a Sample of Adults in Penang, Malaysia.
- Author
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Cheah, Y. K.
- Abstract
Introduction: Given the importance of physical activity to health, this study investigated the socio-demographic determinants of physical activity participation in a sample of adults in Penang. Methods: Through convenience sampling, a total of 398 adults agreed to answer a prepared questionnaire on their socio-demographic background and physical activity participation. The data were analysed using the binary logit model. Frequent physical activity participation is defined as taking part more than 11 times in leisure-time physical activity such as swimming and jogging, each time lasting more than 15 minutes in a typical month, whereas participation that is less than the frequency and time duration specified above is referred to as infrequent physical activity. Results: Age, male, being Chinese, high educational attainment, self-rated excellent health status and presence of family illnesses are positively associated with the likelihood of frequent participation in physical activity. On the contrary, being married, having low income and residing in rural areas are inversely related with the propensity of frequent physical activity participation. Conclusion: The majority in this sample of adults do not participate in physical activity frequently, and the reasons given include lack of health awareness, limited leisure time, budget constraints, and lack of sports amenities. [ABSTRACT FROM AUTHOR]
- Published
- 2011
20. Antibiotic resistance and biosafety of Vibrio cholerae and Vibrio parahaemolyticus from freshwater ish at retail level.
- Author
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Noorlis, A., Ghazali, F. M., Cheah, Y. K., Tuan Zainazor, T. C., Wong, W. C., Tunung, R., Pui, C. F., Nishibuchi, M., Nakaguchi, Y., and Son, R.
- Subjects
ANTIBIOTICS ,VIBRIO ,VIBRIO cholerae ,MICROORGANISMS ,TILAPIA ,FISHES - Abstract
A total of 49 isolates of V. parahaemolyticus and 8 isolates of V. cholerae isolated from freshwater fish of patin (Pangasius hypopthalmus) and red tilapia (Oreochromis sp.) were purchased from different retail level in Selangor, Malaysia. All of the isolates showed a multiple resistances towards all 15 antibiotics tested. Some of the isolates show a high resistance to different antibiotics including bacitracin, vancomycin, tetracycline, furazididone, cephalothin and erythromycin. However, both species was susceptible towards imipenem. Overall antibiotics resistance patterns of all isolates were resistant from 2 to 14 resistance patterns with multiple antibiotic resistance (MAR) index ranging from 0.13 to 0.93 respectively. As the results obtained in the dendrogram produced from both species had indicates that these antibiotics were intensively used whether in the aquaculture farm through feeds during culture or at the hatchery production of seed. Thus, this study will provides an essential information of the MAR index and also the clustering analysis in order to determine the biosafety of Vibrio spp. in freshwater aquaculture fish sold at different retail level in Malaysia. [ABSTRACT FROM AUTHOR]
- Published
- 2011
21. Antibiotic resistance and plasmid profiling of Vibrio parahaemolyticus isolated from cockles (Anadara granosa) at Tanjung Karang, Kuala Selangor.
- Author
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Lesley, M. B., Velnetti, L., Cheah, Y. K., Son, R., Kasing, A., Samuel, L., Micky, V., and Nishibuchi, M.
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VIBRIO parahaemolyticus ,ANTIBIOTICS ,PLASMIDS ,ANADARA ,DRUG resistance ,CYTOPLASMIC inheritance ,FISHERY products - Abstract
A total of sixty V. parahaemolyticus strains isolated from local cockles (Anadara granosa) were investigated by their antibiotic resistance patterns and plasmid profiles. The isolates showed multiple resistances towards most of the antibiotics tested. All strains of V. parahaemolyticus isolated harbored 1-3 plasmids, with sizes ranging from 2.7 to 54 kb. All V. parahaemolyticus strains showed high multiple antibiotics in frequencies of 0.58 - 0.94 indicating that the strains were derived from high-risk sources. In addition, no particular plasmid profile was predictive of a particular pattern of antibiotic susceptibility. These findings are essential because of the suggested involvement of seafood especially shellfish and environment in transmission of this pathogen to human. Thus, indicating that seafood may be a source of food- acquired antibiotic resistant bacteria to consumer. [ABSTRACT FROM AUTHOR]
- Published
- 2011
22. Using RAPD-PCR as molecular assessment on the performance of CHROMAgar Listeria and PALCAM agar on isolation of Listeria spp. and L. monocytogenes from foods.
- Author
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Lee, H. Y., Chai, L. C., Pui, C. F., Tunung, R., Wong, W. C., Shuhaimi, M., Cheah, Y. K., Farinazleen, M. G., Nishibuchi, M., and Son, R.
- Subjects
LISTERIA monocytogenes ,BEEF ,COOKING ,LISTERIA ,AGAR ,RAPD technique ,POLYMERASE chain reaction - Abstract
In this study, Listeria spp. were isolated from naturally contaminated samples of beef burger, minced beef and sliced cheese using PALCAM and CHROMagar™. Samples were enriched with FDA-BAM method and plated on PALCAM and CHROMagar™ Listeria before confirmation using PCR on hlyA and LLO toxin genes specific to L. monocytogenes. Identification of isolates showed a total of 45 isolates of Listeria spp. and two L. monocytogenes. All the 47 isolates were then subjected to RAPD analysis using two oligomers (OPA14 and OPA15) and fingerprint clustering was able to cluster the L. monocytogenes from Listeria spp. based on isolation from agar types as well as L. monocytogenes from Listeria spp. Studies showed that OPA14 and OPA15 are useful for rapid discrimination of Listeria spp. and L. monocytogenes. The differences observed on the isolation of Listeria spp. from PALCAM and CHROMagar™ Listeria that may have an impact on epidemiological studies. [ABSTRACT FROM AUTHOR]
- Published
- 2011
23. Prevalence and quantification of Vibrio species and Vibrio parahaemolyticus in freshwater fish at hypermarket level.
- Author
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Noorlis, A., Ghazali, F. M., Cheah, Y. K., Tuan Zainazor, T. C., Ponniah, J., Tunung, R., Tang, J. Y. H., Nishibuchi, M., Nakaguchi, Y., and Son, R.
- Subjects
VIBRIO ,VIBRIO parahaemolyticus ,FRESHWATER fishes ,FISH microbiology ,FRESHWATER animals ,CATFISHES - Abstract
Little is known on the biosafety level of Vibrio spp. in freshwater fish in Malaysia. The purpose of this study was to investigate the prevalence and concentration of Vibrio spp. and V. parahaemolyticus in freshwater fish using the Most Probable Number-Polymerase Chain Reaction (MPN-PCR) method. The study was conducted on 150 samples from two types of freshwater fish commonly sold at hypermarkets, i.e. Pangasius hypophthalmus (catfish) and Oreochromis sp. (red tilapia). Sampling was done on the flesh, intestinal tract and gills of each fish. The prevalence of Vibrio spp. and V. parahaemolyticus was found to be 98.67% and 24% respectively with higher percentages detected in samples from the gills followed by the intestinal tract and flesh. Vibrio spp. was detected in almost all red tilapia and catfish samples. V. parahaemolyticus was detected in 25% of the catfish samples compared to 22.6% of red tilapia fish. The density of Vibrio spp. and V. parahaemolyticus in the samples ranged from 0 to 1.1x10
7 MPN/g. Although the maximum value was 1.1x107 MPN/g, most samples had microbial loads ranging from 0 to >104 MPN/g. The outcome on the biosafety assessment of Vibrio spp. and V. parahaemolyticus in freshwater fish indicates another potential source of food safety issues to consumers. [ABSTRACT FROM AUTHOR]- Published
- 2011
24. Occurrence of Norovirus GI in green and red onion.
- Author
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Noor Hidayah, M. S., Tuan Zainazor, C., Pui, C. F., Noorlis, A., Noor Eliza, M. R., Naziehah, M. D., Ghazali, F. M., Cheah, Y. K., Nakaguchi, Y., Nishibuchi, M., and Son, R.
- Subjects
NOROVIRUSES ,ALLIUM fistulosum ,ONION diseases & pests ,RNA viruses ,MALAYSIAN cooking - Abstract
Several Norovirus cases due to consumption of green onions have been reported during recent years but reports on red onions are not found. Onions are one of the major tastes in Malaysian food which are sometimes consuming raw especially the green onion. Viral contamination in onions can occur due to planting condition and not properly prepared food. This situation can pose the human health risk. A method was developed to detect the Norovirus that might present on different type of onions. In this study, 60 samples were collected from local market. Elution by Tryptose Phosphate Glycine broth and concentration steps using negatively charge filter were applied to enhance the detection of virus in food due to low copies of virus on food surface. The viral RNA was extracted using Qiagen Rneasy Mini kit before further detection using One-step RT-PCR. The total incidence of Norovirus in green onion and red onion was 13.33% (4/30) and 3.33 % (1/30) respectively. This is the first report of the detection of Norovirus in red and green onions in Malaysia. Based on the results, it is concluded that this method is reliable to detect Norovirus on onions and vegetables surface and hence can be applied in the laboratories for routine or food borne outbreak investigation. [ABSTRACT FROM AUTHOR]
- Published
- 2011
25. Salmonella: A foodborne pathogen.
- Author
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Pui, C. F., Wong, W. C., Chai, L. C., Tunung, R., Jeyaletchumi, P., Noor Hidayah, M. S., Ubong, A., Farinazleen, M. G., Cheah, Y. K., and Son, R.
- Subjects
SALMONELLA ,FOOD pathogens ,EPIDEMIOLOGY ,ANTIBIOTICS ,QUORUM sensing ,FOOD microbiology - Abstract
Salmonellosis continues to be a major public health problem worldwide. It also contributes to negative economic impacts due to the cost of surveillance investigation, treatment and prevention of illness. As such, research on Salmonella has gained great interest and concern from scientists. The purpose of this review is to discuss the classification and nomenclature, characteristic, clinical manifestation, epidemiology, transmission vehicles, antibiotic resistance and quorum sensing of Salmonella. [ABSTRACT FROM AUTHOR]
- Published
- 2011
26. The used of recombinant plasmid DNA in GMO quantitative analysis of insect resistance maize targeted unapproved StarLink corn and approved Bt176 corn in food and feed sold commercially sold Malaysia.
- Author
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Khoo, S. P., Cheah, Y. K., and Son, R.
- Subjects
TRANSGENIC organisms ,RECOMBINANT DNA ,CORN ,PLASMIDS ,BACILLUS thuringiensis ,TRANSGENIC plants - Abstract
Genetically modified organisms (GMO) are increased remarkably from year to year and the estimated global area cultivated with genetically modified (GM) crops reached 125 million hectares in year 2008. However, insect resistance maize based on Bacillus thuringienses (Bt) is of the most cultivated GM crop in worldwide. Bacillus thuringiensis (Bt) is an aerobic, gram-positive bacterium that synthesize one or more Cry protein that are toxic to various types crop and forestry insects pests. To date, several cry genes have been introduced into GM plant to combat with various type of insect. Worldwide commercialization of GM crops has raised the customers' concern about the Biosafety issues, and thus, many countries have implemented the labeling legislations for GM food and their derivatives. In this study, we introduced the quantitative analysis method based on the recombinant plasmid DNA as calibrators that can be used to determine the percentage of GMO content in various types of food and feed samples. Therefore, we have reported 7.5% (6/80) of the samples were contained StarLink maize and 1.25% (1/80) samples were contained Bt176 maize. Additionally, the percentage of GM content in each positive sample were further determined with the developed quantitative method. The percentage of the StarLink corns that present in the positive samples were varies from 0.09% to 2.53% and Bt176 corn that present in the positive sample was 16.90%. The present study demonstrated that the recombinant plasmid DNA that used in quantitative real-time method as good alternative quantitative analysis of GM content. [ABSTRACT FROM AUTHOR]
- Published
- 2011
27. Biosafety assessment of Listeria monocytogenes in vegetarian burger patties in Malaysia.
- Author
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Wong, W. C., Pui, C. F., Chai, L. C., Lee, H. Y., Ghazali, F. M., Tang, J. Y. H., Ponniah, J., Tuan Zainazor, T. C., Cheah, Y. K., and Son, R.
- Subjects
LISTERIA monocytogenes ,VEGETARIAN cooking ,VEGETARIAN foods ,HAMBURGERS ,MALAYSIAN cooking - Abstract
The aim of this study was to examine vegetarian burger patties manufactured by two producers in Malaysia for the presence of Listeria monocytogenes. Brand A was produced by an established food manufacturer while Brand B was produced by a small-scaled food producer. A total of 108 samples of vegetarian burger patties produced by both manufacturers were sampled from retail market and were analyzed by combined MPN-PCR and MPN plating method. Of all the samples tested, ten (9.3%) were found to be contaminated with L. monocytogenes. The L. monocytogenes contamination level in vegetarian burger patties manufactured by producer A (20.9% of the samples were contaminated with 3-1100 MPN/g of L. monocytogenes) was significantly higher (P<0.05) than vegetarian burger patties manufactured by producer B (1.5% of the samples harbored 9.2 MPN/g of L. monocytogenes). Based on the detection and isolation rate obtained with MPN-PCR and MPN-plating, the recovery rate of the L. monocytogenes was estimated to be only 40.0% by MPN-plating approach. [ABSTRACT FROM AUTHOR]
- Published
- 2011
28. Biofilm formation by Salmonella Typhi and Salmonella Typhimurium on plastic cutting board and its transfer to dragon fruit.
- Author
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Pui, C. F., Wong, W. C., Chai, L. C., Lee, H. Y., Tang, J. Y. H., Noorlis, A., Farinazleen, M. G., Cheah, Y. K., and Son, R.
- Subjects
BIOFILMS ,SALMONELLA typhi ,SALMONELLA typhimurium ,FOODBORNE diseases ,MICROBIAL aggregation ,SALMONELLA - Abstract
Adhesion of microorganism to food contact surface can become a source of microbial contamination. Enhanced resistances to environmental stresses are exhibited by biofilm producers. In this study, biofilm formation by Salmonella Typhi and Salmonella Typhimurium on plastic cutting board was accessed before the evaluation of the transfer of these two pathogens from plastic cutting board to dragon fruit. By using crystal violet assay, it was found that the adhesion on plastic cutting board by these two pathogens was the greatest at time 12 h. Results showed that Salmonella adhesion is strain-dependent and varied with time. The mean transfer rate from contaminated plastic cutting board to dragon fruit was examined to be 0.79 and 0.72 for Salmonella Typhi and Salmonella Typhimurium, respectively. This indicated that there is a risk of cross-contamination which should be concerned. [ABSTRACT FROM AUTHOR]
- Published
- 2011
29. Humoral response to SARS-CoV-2 vaccines among healthcare workers in a tertiary hospital in Malaysia.
- Author
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Amrina MA, Shahidah M, Sofiah HR, Mirlia SCM, Thilakaveni R, Chong ZL, Mohd-Hatta AM, Cheah YK, Aidalina M, Niazlin MT, Syafinaz AN, Abdullah M, and Muhammad MI
- Subjects
- Humans, Malaysia, Tertiary Care Centers, SARS-CoV-2, Health Personnel, Vaccination, Vaccines, Inactivated, COVID-19 Vaccines, COVID-19 prevention & control
- Abstract
Introduction: Healthcare workers (HCWs) were among the first to be fully vaccinated against SARS-CoV-2. However, the antibody responses to the vaccines and potential decline among Malaysian HCW are still unclear. The objective of this study is to follow-up anti-S antibody levels among HCW vaccinated with mRNA vaccine (BTN162b2) and inactivated vaccine (CoronaVac)., Materials and Methods: Plasma samples were collected prevaccination, 2 weeks and 6 months post-vaccination and tested for total immunoglobulin levels using ELISA method., Results: A small percentage of HCW (2.2%, 15/677) had elevated anti-S antibody levels in their pre-vaccination plasma samples (median 20.4, IQR 5.8), indicating that they were exposed to SARS-CoV-2 infection prior to vaccination. The mRNA vaccine significantly increased anti-S levels of both previously infected and uninfected individuals to saturation levels (median 21.88, IQR.0.88) at 2 weeks postsecond dose of the vaccine. At 6 months post-vaccination, the antibody levels appeared to be maintained among the recipients of the mRNA vaccine. However, at this time point, anti-S antibody levels were lower in individuals given inactivated vaccine (median 20.39, IQR 7.31, n=28), and interestingly, their antibody levels were similar to anti-S levels in pre-vaccination exposed individuals. Antibody levels were not different between the sexes., Conclusion: Anti-S levels differ in individuals given the different vaccines. While further study is required to determine the threshold level for protection against SARSCoV- 2, individuals with low antibody levels may be considered for boosters.
- Published
- 2023
30. Prevalence of COVID-19 among healthcare workers in the paediatric department: Estimates from a multicenter cross-sectional survey in Negeri Sembilan.
- Author
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David NCE, Juliana H, Chok M, Gan YZ, Tan YC, Nur Adlina MN, Tan SL, Tan MV, Aina Mariana AM, Hasri H, Lee ML, and Cheah YK
- Subjects
- Humans, Child, Child, Preschool, Cross-Sectional Studies, Prevalence, SARS-CoV-2, Pandemics, Health Personnel, COVID-19 epidemiology
- Abstract
Introduction: The COVID-19 pandemic has reached a phase where many have been infected at least once. Healthcare workers were not spared from being infected. This study aimed to determine the period prevalence of COVID-19 among the paediatric healthcare workers in Negeri Sembilan as the country transitioned into an endemic phase of the pandemic. Additionally, we investigate potential sociodemographic and occupational characteristics associated with SARS-CoV-2 infection among healthcare workers., Materials and Methods: A cross-sectional study was conducted among the healthcare workers in the paediatric department at three public specialist hospitals in Negeri Sembilan between 15 and 21 April 2022. Data were collected through a self-administered questionnaire., Results: Out of the 504 eligible healthcare workers, 493 participated in this study (response rate 97.8%). The overall prevalence of COVID-19 (11 March 2020-15 April 2022) among healthcare workers was 50.9%. The majority (80.1%) were infected during the Omicron wave two months before the survey. Household contacts accounted for 35.9% of infection sources. The proportion of non-doctors in the COVID-19-infected group was significantly higher compared to the non-infected group (74.1% vs 64.0%, p=0.016). The COVID-19-infected group had a higher proportion of schoolgoing children (44.6% vs 30.6%, p=0.001) and children who attended pre-school/sent to the babysitter (49.0% vs 24.4%, p<0.001). There were no significant differences between infection rates among the healthcare workers working in the tertiary hospital and the district hospitals. There were also no significant differences in the proportion of COVID-19- infected doctors and nurses when analysed by seniority., Conclusion: Our study provided an estimate on the prevalence of COVID-19 among paediatric healthcare workers in Negeri Sembilan and the factors associated with infection, which captures the extent and magnitude of this pandemic on the state's paediatric department. Most infections resulted from household contact, with a higher proportion of infected healthcare workers having young children.
- Published
- 2023
31. Association of Suicidal Ideation with Demographic, Lifestyle and Health Factors in Malaysians.
- Author
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Cheah YK, Azahadi M, Phang SN, and Abd Manaf NH
- Subjects
- Adult, Cross-Sectional Studies, Female, Humans, Malaysia, Male, Risk Factors, Young Adult, Health Status, Life Style, Socioeconomic Factors, Suicidal Ideation
- Abstract
Objective: To determine the association of suicidal ideation with demographic, lifestyle, and health factors, using data from National Health and Morbidity Survey 2011 (NHMS 2011) of Malaysia., Methods: The NHMS 2011 included 10,141 respondents. Independent variables of suicidal ideation were income, age, household size, sex, ethnicity, education, marital status, smoking, physical activity, and self-rated health. The risk factors of suicidal ideation were determined using logistic regression analysis., Results: In the pooled sample, suicidal ideation was associated with age, sex, ethnicity, and self-rated health, but not associated with income, household size, education, physical activity, or smoking., Conclusion: The likelihood of having suicidal ideation is positively associated with young adults, women, Indians, and those with poor self-rated health.
- Published
- 2018
32. Management of T1DM in children and adolescents in primary care.
- Author
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Hong Y, Hassan N, Cheah YK, Jalaludin MY, and Kasim ZM
- Abstract
The Clinical Practice Guidelines on the Management of Type 1 Diabetes Mellitus in Children & Adolescents was developed by a multidisciplinary development group and approved by the Ministry of Health Malaysia in 2015. A systematic review of 15 clinical questions was conducted using the evidence retrieved mainly from MEDLINE and Cochrane databases. Critical appraisal was done using the Critical Appraisal Skills. Recommendations were formulated on the accepted 136 evidences using the principles of Grading Recommendations, Assessment, Development and Evaluation tailored to the local setting. Type 1 diabetes mellitus is a chronic disease, which usually occurs at an early age, and is associated with various complications including retinopathy, nephropathy, neuropathy and cardiovascular morbidity. Good glycaemic control early in the disease results in lower frequency of chronic diabetes complications, which in turn reduces the healthcare cost. Accurate classification of diabetes and optimum management with the aim to achieve glycaemic targets is of utmost importance.
- Published
- 2017
33. The oral microbiome community variations associated with normal, potentially malignant disorders and malignant lesions of the oral cavity.
- Author
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Mok SF, Karuthan C, Cheah YK, Ngeow WC, Rosnah Z, Yap SF, and Ong HKA
- Subjects
- Adult, Aged, Biomarkers, Tumor analysis, Female, Humans, Male, Middle Aged, Mouth pathology, Bacteria pathogenicity, Microbiota drug effects, Mouth microbiology, Mouth Neoplasms microbiology, Neoplasms microbiology
- Abstract
The human oral microbiome has been known to show strong association with various oral diseases including oral cancer. This study attempts to characterize the community variations between normal, oral potentially malignant disorders (OPMD) and cancer associated microbiota using 16S rDNA sequencing. Swab samples were collected from three groups (normal, OPMD and oral cancer) with nine subjects from each group. Bacteria genomic DNA was isolated in which full length 16S rDNA were amplified and used for cloned library sequencing. 16S rDNA sequences were processed and analysed with MOTHUR. A core oral microbiome was identified consisting of Firmicutes, Proteobacteria, Fusobacteria, Bacteroidetes and Actinobacteria at the phylum level while Streptococcus, Veillonella, Gemella, Granulicatella, Neisseria, Haemophilus, Selenomonas, Fusobacterium, Leptotrichia, Prevotella, Porphyromonas and Lachnoanaerobaculum were detected at the genus level. Firmicutes and Streptococcus were the predominant phylum and genus respectively. Potential oral microbiome memberships unique to normal, OPMD and oral cancer oral cavities were also identified. Analysis of Molecular Variance (AMOVA) showed a significant difference between the normal and the cancer associated oral microbiota but not between the OPMD and the other two groups. However, 2D NMDS showed an overlapping of the OPMD associated oral microbiome between the normal and cancer groups. These findings indicated that oral microbes could be potential biomarkers to distinguish between normal, OPMD and cancer subjects.
- Published
- 2017
34. Analysis of TP53 gene expression and p53 level of human hypopharyngeal FaDu (HTB-43) head and neck cancer cell line after microRNA-181a inhibition.
- Author
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Cheah YK, Cheng RW, Yeap SK, Khoo CH, and See HS
- Subjects
- Cell Line, Tumor, Gene Expression Regulation, Neoplastic, Head and Neck Neoplasms pathology, Humans, MicroRNAs antagonists & inhibitors, Tumor Suppressor Protein p53 genetics, Head and Neck Neoplasms genetics, MicroRNAs genetics, Tumor Suppressor Protein p53 biosynthesis
- Abstract
The identification of new biomarkers for early detection of highly recurrent head and neck cancer is urgently needed. MicroRNAs (miRNAs) are small and non-coding RNAs that regulate cancer-related gene expression, such as tumor protein 53 (TP53) gene expression. This study was carried out to analyze TP53 gene expression using real-time PCR and to determine changes in intracellular p53 level by flow cytometry after downregulation of miRNA-181a miRNA inhibitor in the FaDu cell line. TP53 gene expression showed a 3-fold increment and the p53 protein level was also increased in the miRNA-181a-treated cells. In conclusion, miRNA-181a binds to the TP53 gene and inhibits its expression, decreasing the synthesis of p53.
- Published
- 2014
- Full Text
- View/download PDF
35. Formation of biofilm by Listeria monocytogenes ATCC 19112 at different incubation temperatures and concentrations of sodium chloride.
- Author
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Lee HY, Chai LC, Pui CF, Mustafa S, Cheah YK, Nishibuchi M, and Radu S
- Abstract
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.
- Published
- 2013
- Full Text
- View/download PDF
36. Genetic characterization of Arcobacter isolates from various sources.
- Author
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Shah AH, Saleha AA, Zunita Z, Cheah YK, Murugaiyah M, and Korejo NA
- Subjects
- Animals, Arcobacter classification, Cattle, Genetic Variation, Genotype, Meat microbiology, Milk microbiology, Phenotype, Phylogeny, Arcobacter genetics, Environmental Microbiology, Food Microbiology
- Abstract
Arcobacter is getting more attention due to its detection from wide host-range and foods of animal origin. The objective of this study was to determine the prevalence of Arcobacter spp. in various sources at farm level and beef retailed in markets in Malaysia and to assess the genetic relatedness among them. A total of 273 samples from dairy cattle including cattle (n=120), floor (n=30), water (n=18) and milk (n=105) as well as 148 beef samples collected from retail markets were studied. The overall prevalence of Arcobacter in various sources was 15% (63/421). However, source-wise detection rate of Arcobacter spp. was recorded as 26.66% (8/30) in floor, 26.3% (39/148) in beef, 11.11% (2/18) in water, 7.6% (8/105) in milk and 6.66% (8/120) in cattle. Arcobacter butzleri was the frequently isolated species however, a total of 75%, 66.7%, 53.8%, 50% and 12.5%% samples from floor, milk, beef, water and cattle, respectively, were carrying more than one species simultaneously. One (12.5%) cattle and beef sample (2.5%) found to be carrying one Arcobacter spp., A. skirrowii, only. Typing of Arcobacter isolates was done though pulsed field gel electrophoresis (PFGE) after digested with Eag1 restriction endonuclease (RE). Digestion of genomic DNA of Arcobacter from various sources yielded 12 major clusters (≥ 50% similarity) which included 29 different band patterns. A number of closely related A. butzleri isolates were found from beef samples which indicate cross contamination of common type of Arcobacter. Fecal shedding of Arcobacter by healthy animals can contaminate water and milk which may act as source of infection in humans., (Copyright © 2012 Elsevier B.V. All rights reserved.)
- Published
- 2012
- Full Text
- View/download PDF
37. Vancomycin-resistant Enterococcus faecium of multi locus sequence type 18 in Malaysia.
- Author
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Poh LW, Rukman AW, Cheah YK, Norital Z, Nazri AM, and Mariana NS
- Subjects
- Bacterial Proteins, DNA, Bacterial genetics, Electrophoresis, Gel, Pulsed-Field, Gram-Positive Bacterial Infections, Hospitals, Humans, Malaysia, Multilocus Sequence Typing, Vancomycin, Enterococcus faecium, Vancomycin Resistance
- Abstract
Vancomycin-resistant Enterococcus faecium (VREF) in human infections mostly belong to the high-risk, epidemic, clonal complex-17 (CC17) group. Treatment limitation and high conjugation frequency makes it dominant in hospitals worldwide. We investigated positive cultures by Pulse-field gel electrophoresis (PFGE), multi locus sequence typing (MLST). DNA of two strains (A2 and C) appeared to be clonally related by PFGE. Three strains were of ST 18 type (A1, B and C) and strain A2 is of a new ST 596. This ST 18 type strain found in our study is crucial and is believed to be the first in Malaysia.
- Published
- 2012
38. Analysis of Antarctic proteobacteria by PCR fingerprinting and screening for antimicrobial secondary metabolites.
- Author
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Lee LH, Cheah YK, Nurul Syakima AM, Shiran MS, Tang YL, Lin HP, and Hong K
- Subjects
- Bradyrhizobium classification, Bradyrhizobium genetics, Proteobacteria classification, Random Amplified Polymorphic DNA Technique, DNA Fingerprinting methods, DNA, Bacterial genetics, Proteobacteria genetics
- Abstract
Fifty-seven proteobacterium species were successfully isolated from soils of Barrientos Island of the Antarctic using 11 different isolation media. Analysis of 16S rDNA sequencing of these isolates showed that they belonged to eight different genera, namely Bradyrhizobium, Sphingomonas, Methylobacterium, Caulobacter, Paracoccus, Ralstonia, Rhizobium, and Staphylococcus. All isolates were studied for capability of producing antimicrobial and antifungal secondary metabolites using high-throughput screening models. Approximately 23 (13/57) and 2% (1/57) of isolates inhibited growth of Candida albicans ATCC 10231(T) and Staphylococcus aureus ATCC 51650(T), respectively. These results indicated that proteobacterium species isolates from Antarctic could serve as potential source of useful bioactive metabolites. Enterobacterial repetitive intergenic consensus (ERIC)-PCR fingerprinting produced nine clusters and 13 single isolates, with a high D value of 0.9248. RAPD fingerprinting produced six clusters and 13 single isolates, with a relatively low D value of 0.7776. ERIC-PCR analysis proved to have better discrimination capability than RAPD analysis and generated better clustering for all proteobacterium species isolates. We conclude that ERIC-PCR is a robust, reliable and rapid molecular typing method for discriminating different genera of proteobacteria.
- Published
- 2012
- Full Text
- View/download PDF
39. Evaluation of DNA and RNA extraction methods.
- Author
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Edwin Shiaw CS, Shiran MS, Cheah YK, Tan GC, and Sabariah AR
- Subjects
- DNA, Formaldehyde, Polymerase Chain Reaction, Paraffin Embedding, RNA
- Abstract
This study was done to evaluate various DNA and RNA extractions from archival FFPE tissues. A total of 30 FFPE blocks from the years of 2004 to 2006 were assessed with each modified and adapted method. Extraction protocols evaluated include the modified enzymatic extraction method (Method A), Chelex-100 extraction method (Method B), heat-induced retrieval in alkaline solution extraction method (Methods C and D) and one commercial FFPE DNA Extraction kit (Qiagen, Crawley, UK). For RNA extraction, 2 extraction protocols were evaluated including the enzymatic extraction method (Method 1), and Chelex-100 RNA extraction method (Method 2). Results show that the modified enzymatic extraction method (Method A) is an efficient DNA extraction protocol, while for RNA extraction, the enzymatic method (Method 1) and the Chelex-100 RNA extraction method (Method 2) are equally efficient RNA extraction protocols.
- Published
- 2010
40. Dengue-associated adult respiratory distress syndrome.
- Author
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Lum LC, Thong MK, Cheah YK, and Lam SK
- Subjects
- Capillary Permeability, Child, Child, Preschool, Dengue blood, Dengue physiopathology, Female, Humans, Hypoxia physiopathology, Male, Respiratory Distress Syndrome physiopathology, Dengue complications, Respiratory Distress Syndrome etiology
- Abstract
In dengue shock syndrome, an acute increase in capillary permeability results in leakage of plasma into the interstitial space. Pleural effusion is commonly seen in dengue shock syndrome. We report three cases of dengue-associated adult respiratory distress syndrome (ARDS) in children, in all of whom dengue haemorrhagic fever, presenting with grade 3 or grade 4 dengue shock syndrome with disseminated intravascular coagulopathy, was confirmed. The criteria for the diagnosis of ARDS were based on the expanded definition of ARDS by Murray et al. Treatment consisted of fluid resuscitation, correction of coagulopathy and mechanical ventilation. All three children had multi-organ impairment, but it was more severe in the two who died. The one survivor was well at discharge.
- Published
- 1995
- Full Text
- View/download PDF
41. Prevalence and distribution of intestinal and blood parasites among Ibans in the Nanga Atoi in the Second Division in Sarawak.
- Author
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Neo CB, Cheah YK, Chin PW, Tan TV, Wong NC, Yap LM, and Kan SP
- Subjects
- Adolescent, Adult, Aged, Child, Child, Preschool, Female, Helminthiasis epidemiology, Humans, Infant, Malaysia ethnology, Male, Middle Aged, Protozoan Infections epidemiology, Ethnicity, Filariasis epidemiology, Intestinal Diseases, Parasitic epidemiology, Malaria epidemiology
- Published
- 1987
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