Displaying publications 161 - 180 of 247 in total

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  1. Latip RA, Lee YY, Tang TK, Phuah ET, Tan CP, Lai OM
    Food Chem, 2013 Dec 15;141(4):3938-46.
    PMID: 23993569 DOI: 10.1016/j.foodchem.2013.05.114
    The stearin fraction of palm-based diacylglycerol (PDAGS) was produced from dry fractionation of palm-based diacylglycerol (PDAG). Bakery shortening blends were produced by mixing PDAGS with either palm mid fraction, PMF (PDAGS/PMF), palm olein, POL(PDAGS/POL) or sunflower oil, SFO (PDAGS/SFO) at PDAGS molar fraction of XPDAGS=0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%. The physicochemical results obtained indicated that C16:0 and C18:1 were the dominant fatty acids for PDAGS/PMF and PDAGS/POL, while C18:1 and C18:2 were dominant in the PDAGS/SFO mixtures. SMP and SFC of the PDAGS were reduced with the addition of PMF, POL and SFO. Binary mixtures of PDAGS/PMF had better structural compatibility and full miscibility with each other. PDAGS/PMF and PDAGS/SFO crystallised in β'+β polymorphs in the presence of 0.4-0.5% PDAGS while PDAGS/POL resulted in β polymorphs crystal. The results gave indication that PDAGS: PMF at 50%:50% and 60%:40% (w/w) were the most suitable fat blend to be used as bakery shortening.
  2. Ab Latip R, Lee YY, Tang TK, Phuah ET, Lee CM, Tan CP, et al.
    PeerJ, 2013;1:e72.
    PMID: 23682348 DOI: 10.7717/peerj.72
    Fractionation which separates the olein (liquid) and stearin (solid) fractions of oil is used to modify the physicochemical properties of fats in order to extend its applications. Studies showed that the properties of fractionated end products can be affected by fractionation processing conditions. In the present study, dry fractionation of palm-based diacylglycerol (PDAG) was performed at different: cooling rates (0.05, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0°C/min), end-crystallisation temperatures (30, 35, 40, 45 and 50°C) and agitation speeds (30, 50, 70, 90 and 110 rpm) to determine the effect of these parameters on the properties and yield of the solid and liquid portions. To determine the physicochemical properties of olein and stearin fraction: Iodine value (IV), fatty acid composition (FAC), acylglycerol composition, slip melting point (SMP), solid fat content (SFC), thermal behaviour tests were carried out. Fractionation of PDAG fat changes the chemical composition of liquid and solid fractions. In terms of FAC, the major fatty acid in olein and stearin fractions were oleic (C18:1) and palmitic (C16:0) respectively. Acylglycerol composition showed that olein and stearin fractions is concentrated with TAG and DAG respectively. Crystallization temperature, cooling rate and agitation speed does not affect the IV, SFC, melting and cooling properties of the stearin fraction. The stearin fraction was only affected by cooling rate which changes its SMP. On the other hand, olein fraction was affected by crystallization temperature and cooling rate but not agitation speed which caused changes in IV, SMP, SFC, melting and crystallization behavior. Increase in both the crystallization temperature and cooling rate caused a reduction of IV, increment of the SFC, SMP, melting and crystallization behaviour of olein fraction and vice versa. The fractionated stearin part melted above 65°C while the olein melted at 40°C. SMP in olein fraction also reduced to a range of 26 to 44°C while SMP of stearin fractions increased to (60-62°C) compared to PDAG.
  3. Lee YY, Tang TK, Lai OM
    J Food Sci, 2012 Aug;77(8):R137-44.
    PMID: 22748075 DOI: 10.1111/j.1750-3841.2012.02793.x
    Medium- and long-chain triacylglycerol (MLCT) is a modified lipid containing medium- chain (C6-C12) and long-chain fatty acids (C14-C24) in the same triacylglycerol (TAG) molecule. It can be produced either through enzymatic (with 1,3 specific or nonspecific enzyme) or chemical methods. The specialty of this structured lipid is that it is metabolized differently compared to conventional fats and oils, which can lead to a reduction of fat accumulation in the body. Therefore, it can be used for obesity management. It also contains nutritional properties that can be used to treat metabolic problems. This review will discuss on the health benefits of MLCT, its production methods especially via enzymatic processes and its applications in food industries.
  4. Karim NA, Noor AM, Lee YY, Lai OM
    J Food Sci, 2015 Dec;80(12):C2678-85.
    PMID: 26523850 DOI: 10.1111/1750-3841.13119
    The oxidative and thermal stability of low diglycerides palm oil produced via silica treatment (sPO) and enzymatic treatment (ePO) compared with standard quality palm oil (SQ) and premium quality palm oil (PQ) was investigated. Both of the oils displayed better oxidative stability compared with SQ as well as significantly higher (P < 0.05) thermal resistance and oxidative strength than SQ and PQ due to lower amounts of partial glycerides. Although the initial induction periods (IPs) of sPO and ePO were significantly lower compared with SQ and PQ, both the oils showed slower drops in their IP values. The darkening effect after frying was significantly (P < 0.05) slower in sPO compared with SQ, PQ, and ePO. Besides, there is no difference p > 0.05 in the rate of FFA formation between sPO and PQ. The anisidine value and peroxide values were lowest in sPO, followed by ePO, PQ, and SQ.
  5. Lee YY, Tang TK, Phuah ET, Tan CP, Wang Y, Li Y, et al.
    Crit Rev Food Sci Nutr, 2020;60(15):2509-2525.
    PMID: 31418288 DOI: 10.1080/10408398.2019.1650001
    Diacylglycerol (DAG) is a world leading anti-obesity functional cooking oil synthesized via structural modification of conventional fats and oils. DAG exits in three stereoisomers namely sn-1,2-DAG, sn-1,3-DAG, and sn-2,3-DAG. DAG particularly sn-1,3-DAG demonstrated to have the potential in suppressing body fat accumulation and lowering postprandial serum triacylglycerol, cholesterol and glucose level. DAG also showed to improve bone health. This is attributed to DAG structure itself that caused it to absorb and digest via different metabolic pathway than conventional fats and oils. With its purported health benefits, many studies attempt to enzymatically or chemically synthesis DAG through various routes. DAG has also received wide attention as low calorie fat substitute and has been incorporated into various food matrixes. Despite being claimed as healthy cooking oil the safety of DAG still remained uncertain. DAG was banned from sale as it was found to contain probable carcinogen glycidol fatty acid esters. The article aims to provide a comprehensive and latest review of DAG emphasizing on its structure and properties, safety and regulation, process developments, metabolism and beneficial health attributes as well as its applications in the food industry.
  6. Lee YY, Tang TK, Phuah ET, Alitheen NB, Tan CP, Lai OM
    J Sci Food Agric, 2017 Mar;97(5):1379-1385.
    PMID: 27801514 DOI: 10.1002/jsfa.8124
    Non-enzymatic browning has been a wide and interesting research area in the food industry, ranging from the complexity of the reaction to its applications in the food industry as well as its ever-debatable health effects. This review provides a new perspective to the Maillard reaction apart from its ubiquitous function in enhancing food flavour, taste and appearance. It focuses on the recent application of Maillard reaction products as an inexpensive and excellent source of emulsifiers as well as superior encapsulating matrices for the entrapment of bioactive compounds. Additionally, it will also discuss the latest approaches employed to perform the Maillard reaction as well as several important reaction parameters that need to be taken into consideration when conducting the Maillard reaction. © 2016 Society of Chemical Industry.
  7. Lee YY, Tang TK, Phuah ET, Karim NAA, Alitheen NBM, Tan CP, et al.
    Food Res Int, 2018 01;103:200-207.
    PMID: 29389606 DOI: 10.1016/j.foodres.2017.10.022
    Medium-and-Long Chain Triacylglycerol (MLCT) is a type of structured lipid that is made up of medium chain, MCFA (C8-C12) and long chain, LCFA (C16-C22) fatty acid. Studies claimed that consumption of MLCT has the potential in reducing visceral fat accumulation as compared to long chain triacylglycerol, LCT. This is mainly attributed to the rapid metabolism of MCFA as compared to LCFA. Our study was designed to compare the anti-obesity effects of a enzymatically interesterified MLCT (E-MLCT) with physical blend of palm kernel and palm oil (B-PKOPO) having similar fatty acid composition and a commercial MLCT (C-MLCT) made of rapeseed/soybean oil on Diet Induced Obesity (DIO) C57BL/6J mice for a period of four months in low fat, LF (7%) and high fat, HF (30%) diet. The main aim was to determine if the anti-obesity effect of MLCT was contributed solely by its triacylglycerol structure alone or its fatty acid composition or both. Out of the three types of MLCT, mice fed with Low Fat, LF (7%) E-MLCT had significantly (P<0.05) lower body weight gain (by ~30%), body fat accumulation (by ~37%) and hormone leptin level as compared to both the LF B-PKOPO and LF C-MLCT. Histological examination further revealed that dietary intake of E-MLCT inhibited hepatic lipid accumulation. Besides, analysis of serum profile also demonstrated that consumption of E-MLCT was better in regulating blood glucose compared to B-PKOPO and C-MLCT. Nevertheless, both B-PKO-PO and E-MLCT which contained higher level of myristic acid was found to be hypercholesterolemic compared to C-MLCT. In summary, our finding showed that triacylglycerol structure, fatty acid composition and fat dosage play a pivotal role in regulating visceral fat accumulation. Consumption of E-MLCT in low fat diet led to a significantly lesser body fat accumulation. It was postulated that the MLM/MLL/LMM/MML/LLM types of triacylglycerol and C8-C12 medium chain fatty acids were the main factors that contributed to the visceral fat suppressing effect of MLCT. Despite being able to reduce body fat, the so called healthful functional oil E-MLCT when taken in high amount do resulted in fat accumulation. In summary, E-MLCT when taken in moderation can be used to manage obesity issue. However, consumption of E-MLCT may lead to higher total cholesterol and LDL level.
  8. Abdul Wahab P, Mohd Yusoff D, Abdul Kadir A, Ali SH, Lee YY, Kueh YC
    PeerJ, 2020;8:e8581.
    PMID: 32175185 DOI: 10.7717/peerj.8581
    Background: Chronic constipation is a common symptom among the elderly, and it may affect their quality of life (QoL). A lack of available research focused on the elderly means that this effect is not well understood. This study aimed to develop and validate a new scale (Elderly-Constipation Impact Scale (E-CIS)) to measure the impact of chronic constipation on QoL among the elderly.

    Methods: A pool of items was generated from a qualitative study, literature reviews, and expert reviews. Exploratory factor analysis (EFA) was performed on the original 40 items of the E-CIS and followed by 27 items for confirmatory factor analysis (CFA). A total of 470 elderly people with chronic constipation were involved.

    Results: The mean age of the participants was 68.64 ± 6.57. Finally, only 22 items were indicated as appropriately representing the E-CIS, which were grouped into seven subscales: 'daily activities', 'treatment satisfaction', 'lack of control of bodily function', 'diet restriction', 'symptom intensity', 'anxiety' and 'preventive actions'. The scale was confirmed as valid (root mean square error of approximation (RMSEA) = 0.04, comparative fit index (CFI) = 0.961, Tucker-Lewis index (TLI) = 0.952 and chi-square/degree of freedom (chiSq/df) = 1.44) and reliable (Cronbach's alpha: 0.66-0.85, composite reliability (CR) = 0.699-0.851) to assess the impact of chronic constipation on the elderly's QoL.

    Conclusions: The E-CIS is useful to measure the impact of chronic constipation on the elderly's QoL. A further test is needed to determine the validity and reliability of this scale in other elderly population.

  9. Ong J, Ong AML, Ong S, Xin X, Lee YY, Pausawasdi N, et al.
    J Gastroenterol Hepatol, 2021 Nov;36(11):3056-3068.
    PMID: 34159640 DOI: 10.1111/jgh.15594
    BACKGROUND AND AIM: The coronavirus disease 2019 pandemic has impacted gastroenterology practices worldwide; however, its protracted effects within Southeast Asia were unknown. The primary aim of the study was to determine the impact of the pandemic on clinical demands including burnout among gastroenterologists within the region. The secondary aim was to identify risk factors for burnout and determine regional stressors.

    METHODS: This was a mixed-methods study. Gastroenterologists were surveyed electronically between September 1 and December 7, 2020, via gastroenterology and endoscopy societies of Brunei, Indonesia, Malaysia, Philippines, Singapore, and Thailand. Quantitative and qualitative data were collected. The 22-item Maslach Burnout Inventory-Human Services Survey (MBI-HSS) was used to detect burnout. Quantitative data were non-parametric; non-parametric methods were used for statistical comparisons. Logistic regression was used to determine risk factors for burnout. Content analysis method was used to analyze qualitative data. Ethical approval was obtained.

    RESULTS: A total of 73.0% reported that they were still significantly affected by the pandemic. Of these, 40.5% reported increased workload and 59.5% decreased workload. Statistically significant differences in weekly working hours, endoscopy, and inpatient volumes were present. No differences were observed in outpatient volumes, likely because of telemedicine. Burnout was common; however, 50.1% of gastroenterologists were unaware of or did not have access to mental health support. This, as well as depression, being a trainee, and public sector work, increased burnout risk significantly.

    CONCLUSION: The effects of the pandemic are multifaceted, and burnout is common among Southeast Asian gastroenterologists. Safeguards for mental health are suboptimal, and improvements are urgently needed.

  10. Zahari Z, Lee CS, Ibrahim MA, Musa N, Mohd Yasin MA, Lee YY, et al.
    Am J Drug Alcohol Abuse, 2016 09;42(5):587-596.
    PMID: 27284701 DOI: 10.3109/00952990.2016.1172078
    BACKGROUND: Methadone is a substrate of the permeability glycoprotein (P-gp) efflux transporter, which is encoded by the ABCB1 (MDR1) gene. Large interindividual variability in serum methadone levels for therapeutic response has been reported. Genetic variations in ABCB1 gene may be responsible for the variability in observed methadone concentrations.
    OBJECTIVE: This study investigated the associations of ABCB1 polymorphisms and serum methadone concentration over the 24-hour dosing interval in opioid-dependent patients on methadone maintenance therapy (MMT).
    METHODS: One hundred and forty-eight male opioid-dependent patients receiving MMT were recruited. Genomic deoxyribonucleic acid (DNA) was extracted from whole blood and genotyped for ABCB1 polymorphisms [i.e. 1236C>T (dbSNP rs1128503), 2677G>T/A (dbSNP rs2032582), and 3435C>T (dbSNP rs1045642)] using the allelic discrimination real-time polymerase chain reaction (PCR). Blood samples were collected at 0, 0.5, 1, 2, 4, 8, 12, and 24 hours after the dose. Serum methadone concentrations were measured using the Methadone ELISA Kit.
    RESULTS: Our results revealed an association of CGC/TTT diplotype (1236C>T, 2677G>T/A, and 3435C>T) with dose-adjusted serum methadone concentration over the 24-hour dosing interval. Patients with CGC/TTT diplotype had 32.9% higher dose-adjusted serum methadone concentration over the 24-hour dosing interval when compared with those without the diplotype [mean (SD) = 8.12 (0.84) and 6.11 (0.41) ng ml-1mg-1, respectively; p = 0.033].
    CONCLUSION: There was an association between the CGC/TTT diplotype of ABCB1 polymorphisms and serum methadone concentration over the 24-hour dosing interval among patients on MMT. Genotyping of ABCB1 among opioid-dependent patients on MMT may help individualize and optimize methadone substitution treatment.
    Study site: Psychiatric Clinic, Hospital Universiti Sains Malaysia (HUSM), and other MMT clinics in Kelantan,
    Malaysia
  11. Lee YY, Bee PC, Lee CK, Naiker M, Ismail R
    Ann Dermatol, 2011 Dec;23(Suppl 3):S390-2.
    PMID: 22346286 DOI: 10.5021/ad.2011.23.S3.S390
    Bullous pemphigoid (BP) has a recognized association with solid organ tumors, but is relatively rare in hematological malignancies. We report a 67-year-old male who developed BP after being diagnosed with myelodysplastic syndrome and refractory anemia with excess of blast (RAEB). Skin biopsy elucidated sub-epidermal bulla using direct immunofluorescence, revealing linear C3 and IgG deposits along the basement membrane. His BP was recalcitrant to the conventional treatment and only responded to a combination of high dose oral prednisolone and azathioprine. The relative refractory nature of his condition and concurrent RAEB supports a paraneoplastic nature.
  12. Zahari Z, Lee CS, Ibrahim MA, Musa N, Yasin MA, Lee YY, et al.
    Pain Ther, 2015 Dec;4(2):179-96.
    PMID: 26581429 DOI: 10.1007/s40122-015-0041-y
    We recently reported that a majority of opioid-dependent Malay males on methadone therapy are cold pain sensitive. It is postulated that common OPRM1 polymorphisms may be responsible. This study investigated the association between 118A>G (dbSNP rs1799971) and IVS2+691G>C (dbSNP rs2075572) variants on cold pain responses among opioid-dependent Malay males on methadone maintenance therapy.
  13. Zahari Z, Lee CS, Ibrahim MA, Musa N, Mohd Yasin MA, Lee YY, et al.
    J Pharm Pharm Sci, 2016;19(1):127-36.
    PMID: 27096697 DOI: 10.18433/J3NS49
    PURPOSE: This study compared pain sensitivity among opioid dependent patients on methadone maintenance therapy (MMT) and opioid naive subjects.

    METHODS: The three hundred participants comprised 152 opioid naive subjects and 148 opioid dependent patients. Opioid naive subjects had not taken any opioids including morphine and methadone to their best knowledge and were presumed so after two consecutive negative urine screenings for drugs. All opioid dependent patients were stabilized in treatment, defined as having been enrolled in the program for more than one month with no change of methadone dosage over the past one month. Excluded from the study were individuals with chronic or ongoing acute pain and individuals with a history of analgesics ingestion within 3 d before the cold pressor test (CPT). Pain tolerance to CPT was evaluated at 0 h, and at 2, 4, 8, 12, and 24 h post-methadone dose.

    RESULTS: Patients exhibited a significantly shorter mean pain tolerance time of 34.17 s (95% CI 24.86, 43.49) versus 61.36 (52.23, 70.48) [p < 0.001] compared with opioid naive subjects. Time-dependent mean pain tolerance was also significantly different when naive subjects were compared to patients (p = 0.016).

    CONCLUSIONS: This study revealed hyperalgesia amongst patients on MMT, as manifested by their quicker hand withdrawal. The complaints of pain in this population should not be underestimated and the pain should be evaluated seriously and managed aggressively.

  14. Zahari Z, Lee CS, Ibrahim MA, Musa N, Mohd Yasin MA, Lee YY, et al.
    Drug Alcohol Depend, 2016 08 01;165:143-50.
    PMID: 27289271 DOI: 10.1016/j.drugalcdep.2016.05.028
    BACKGROUND: CYP2B6 polymorphisms contribute to inter-individual variations in pharmacokinetics of methadone. Increased pain sensitivity is frequently reported by opioid dependent patients on methadone maintenance therapy (MMT). It is possible, therefore, that genetic polymorphisms in CYP2B6, which affects the metabolism of methadone, influence pain sensitivity among patients on MMT. This study investigated CYP2B6 polymorphisms and pain sensitivity in this group.

    METHODS: The cold pressor pain responses of 148 opioid dependent patients receiving MMT were evaluated using the cold pressor test (CPT). DNA was extracted from whole blood and subjected to polymerase chain reaction (PCR)-genotyping.

    RESULTS: Of the 148 subjects, 77 (52.0%) were carriers of CYP2B6*6 allele. CYP2B6*6 allele carriers had shorter cold pain threshold and pain tolerance times than non-carriers of CYP2B6*6 allele (21.05s vs 33.69s, p=0.036 and 27.15s vs 44.51s, p=0.020, respectively). Pain intensity scores of the CYP2B6*6 allele carriers was 67.55, whereas that of the CYP2B6*6 allele non-carriers was 64.86 (p=0.352).

    CONCLUSION: Our study indicates that the CYP2B6*6 allele is associated with a lower pain threshold and lower pain tolerance among males with opioid dependence on MMT. The CYP2B6*6 allele may provide a mechanistic explanation for clinical observations of heightened pain sensitivity among opioid dependent patients receiving MMT.

  15. Zahari Z, Lee CS, Ibrahim MA, Musa N, Mohd Yasin MA, Lee YY, et al.
    Pain Ther, 2016 Jun;5(1):43-54.
    PMID: 26792136 DOI: 10.1007/s40122-016-0044-3
    INTRODUCTION: Methadone is a full agonist of the opioid receptor mu 1 which is encoded by the OPRM1 gene. Sleep disorders were frequently reported by opioid-dependent patients during methadone maintenance therapy (MMT). It is possible, therefore, that genetic polymorphisms in OPRM1 influence sleep quality among patients on MMT. This study investigated the association of OPRM1 polymorphisms with sleep quality among opioid-dependent patients on MMT.
    METHODS: The sleep quality of 165 male opioid-dependent patients receiving MMT was evaluated using the Pittsburgh Sleep Quality Index (PSQI). DNA was extracted from whole blood and subjected to polymerase chain reaction (PCR) genotyping.
    RESULTS: Patients with IVS2 + 691 CC genotype had higher PSQI scores [mean (SD) = 5.73 (2.89)] compared to those without the IVS2 + 691 CC genotype (IVS2 + 691 GG/GC genotype) [4.92 (2.31)], but the difference did not reach statistical significance (p = 0.081). Patients with combined 118 AA genotype and IVS2 + 691 GC genotype (AC/AG diplotype) had significantly lower PSQI scores [mean (SD) = 4.25 (2.27)] compared to those without the diplotype [5.68 (2.77)] (p = 0.018).
    CONCLUSION: Our study indicates that the AC/AG diplotype for the 118A>G and IVS2 + 691G>C polymorphisms of OPRM1 gene is associated with better sleep quality among males with opioid dependence on MMT.
    KEYWORDS: AC/AG diplotype; Male patients; Methadone; Methadone maintenance therapy; OPRM1; Opioid dependence; Opioid receptor; Opioid receptor, mu 1 gene; Pittsburgh Sleep Quality Index; Sleep quality
  16. Zahari Z, Lee CS, Tan SC, Mohamad N, Lee YY, Ismail R
    PeerJ, 2015;3:e839.
    PMID: 25870765 DOI: 10.7717/peerj.839
    Aim. Poor sleep quality due to pain has been reported among opioid-dependent male patients on methadone maintenance therapy (MMT) but objective pain data are lacking. This study aimed to investigate the rate of pain-sensitivity using cold pressor test (CPT) and the relationship between pain-sensitivity and sleep quality in this population.
    Methods. A total of 168 male participants were included into the study. Objective pain-tolerance was evaluated at 0 h and at 24 h after the first CPT. Malay version of the Pittsburgh Sleep Quality Index (PSQI) and the subjective opiate withdrawal scale (SOWS) questionnaires were administered to evaluate the quality of sleep and withdrawal symptoms, respectively.
    Results. The mean age of study participants was 37.22 (SD 6.20) years old. Mean daily methadone dose was 76.64 (SD 37.63) mg/day, mean global PSQI score was 5.47 (SD 2.74) and mean averaged SOWS score was 5.43 (SD 6.91). The averaged pain-tolerance time ranged from 7 to 300 s with a mean time of 32.16 (SE 2.72) s, slightly below the cut-off score of 37.53 s. More specifically, 78.6% (n = 132) of participants were identified as pain-sensitive (averaged pain-tolerance time ≤37.53 s), and 36 (21.4%) participants were pain-tolerant (averaged pain-tolerance time >37.53 s). The pain-sensitive group reported poorer sleep quality with mean (SD) PSQI of 5.78 (2.80) compared with the pain-tolerant group with mean (SD) PSQI of 4.31 (2.18) (p = 0.005). With analysis of covariance, pain-sensitive group was found to have higher global PSQI scores (adjusted mean 5.76, 95% CI 5.29; 6.22) than pain-tolerant participants (adjusted mean 4.42, 95% CI 3.52; 5.32) (p = 0.010).
    Conclusions. Majority of opioid-dependent male patients on methadone treatment are pain-sensitive with CPT. Poor sleep quality is associated with cold pressor pain-sensitivity. Pain and sleep complaints in this male population should not be overlooked.
    Study site: Hospital Universiti Sains Malaysia (HUSM) and other MMT clinics (Kota Bharu, Pasir Mas, Pasir Puteh and Bachok), Kelantan, Malaysia
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