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  1. Tan CS, Low SK, Viapude GN
    Psych J, 2018 Sep;7(3):133-143.
    PMID: 30015375 DOI: 10.1002/pchj.220
    Studies have found that extraversion enhances happiness indirectly through social support. However, it is unclear how social support may be connected to happiness. On the basis of a literature review, we hypothesize that individual hope may play an important role in the relationship between social support and happiness. Using a serial mediation model, the present study attempted to investigate the hypothetical mediating role of hope in the relationship between extraversion and happiness and between social support and happiness. Analysis of responses of 360 undergraduate students showed that extraversion, social support, and hope were significantly linked with happiness. Moreover, hope was found to mediate the linkage of extraversion and happiness and of social support and happiness. The results also supported the view that extraversion enhances happiness through social support and then hope (serial mediating effect). Lastly, the serial mediating effect was found to be significantly lower than the other two indirect effects. The findings offer insights into the effect of social support on happiness and extend the understanding of the relationship between extraversion and happiness.
  2. Saad HM, Sim KS, Tan YS
    Int J Med Mushrooms, 2018;20(2):141-153.
    PMID: 29773006 DOI: 10.1615/IntJMedMushrooms.2018025463
    Five culinary-medicinal mushrooms are commonly available in the Malaysian market: Agaricus bisporus (white and brown), Ganoderma lucidum, Hypsizygus marmoreus, Pleurotus floridanus, and P. pulmonarius. These species were selected for use in the current study, the aim of which was to investigate the antimelanogenesis and anti-inflammatory activity of these mushrooms in an attempt to evaluate their potential use in cosmeceuticals. Mushroom fruiting bodies were extracted with hot water, and the extracts were freeze-dried before testing. The antimelanogenesis activity of the extracts was determined by cell viability assay, measurement of intracellular melanin content, and cellular tyrosinase assay with B16F10 melanoma cells. The anti-inflammatory activity of the mushroom extracts was tested by measuring the levels of nitric oxide (NO), tumor necrosis factor (TNF)-α, and interleukin-10 excreted by RAW264.7 macrophages. Brown A. bisporus reduced intracellular melanin content to the largest extent-up to 57.05 ± 3.90%-without a cytotoxic effect on B16F10 melanoma cells. This extract also reduced cellular tyrosinase activity to 17.93 ± 2.65%, performing better than kojic acid, the positive control. In parallel, the extract from brown A. bisporus, at the highest concentration tested, has appreciable anti-inflammatory activity through reductions of NO and TNF-α levels. The other 5 extracts showed moderate antimelanogenesis and anti-inflammatory activities. In summary, our findings show that A. bisporus (brown) extract has the potential to be used as an ingredient in whitening skincare products and to sooth the inflammatory response on the skin.
  3. Ha J, Tan PP, Goh KL
    PLoS One, 2018;13(5):e0197785.
    PMID: 29782534 DOI: 10.1371/journal.pone.0197785
    The energy-growth nexus has important policy implications for economic development. The results from many past studies that investigated the causality direction of this nexus can lead to misleading policy guidance. Using data on China from 1953 to 2013, this study shows that an application of causality test on the time series of energy consumption and national output has masked a lot of information. The Toda-Yamamoto test with bootstrapped critical values and the newly proposed non-linear causality test reveal no causal relationship. However, a further application of these tests using series in different time-frequency domain obtained from wavelet decomposition indicates that while energy consumption Granger causes economic growth in the short run, the reverse is true in the medium term. A bidirectional causal relationship is found for the long run. This approach has proven to be superior in unveiling information on the energy-growth nexus that are useful for policy planning over different time horizons.
  4. Tan SH, Balachandran R, Prepageran N
    Eur J Intern Med, 2019 02;60:e3-e4.
    PMID: 29759815 DOI: 10.1016/j.ejim.2018.05.012
  5. Tan KX, Lau SY, Danquah MK
    Biomed Pharmacother, 2018 May;101:996-1002.
    PMID: 29635910 DOI: 10.1016/j.biopha.2018.03.052
    Targeted drug delivery is a promising strategy to promote effective delivery of conventional and emerging pharmaceuticals. The emergence of aptamers as superior targeting ligands to direct active drug molecules specifically to desired malignant cells has created new opportunities to enhance disease therapies. The application of biodegradable polymers as delivery carriers to develop aptamer-navigated drug delivery system is a promising approach to effectively deliver desired drug dosages to target cells. This study reports the development of a layer-by-layer aptamer-mediated drug delivery system (DPAP) via a w/o/w double emulsion technique homogenized by ultrasonication or magnetic stirring. Experimental results showed no significant differences in the biophysical characteristics of DPAP nanoparticles generated using the two homogenization techniques. The DPAP formulation demonstrated a strong targeting performance and selectivity towards its target receptor molecules in the presence of non-targets. The DPAP formulation demonstrated a controlled and sustained drug release profile under the conditions of pH 7 and temperature 37 °C. Also, the drug release rate of DPAP formulation was successfully accelerated under an endosomal acidic condition of ∼pH 5.5, indicating the potential to enhance drug delivery within the endosomal micro-environment. The findings from this work are useful to understanding polymer-aptamer-drug relationship and their impact on developing effective targeted delivery systems.
  6. Tan KK, Nellis S, Zulkifle NI, Sulaiman S, AbuBakar S
    Epidemiol Infect, 2018 10;146(13):1635-1641.
    PMID: 29860959 DOI: 10.1017/S0950268818001425
    Dengue virus type 3 genotype III (DENV-3/III) is widely distributed in most dengue-endemic regions. It emerged in Malaysia in 2008 and autochthonously spread in the midst of endemic DENV-3/I circulation. The spread, however, was limited and the virus did not cause any major outbreak. Spatiotemporal distribution study of DENV-3 over the period between 2005 and 2011 revealed that dengue cases involving DENV-3/III occurred mostly in areas without pre-existing circulating DENV-3. Neutralisation assays performed using sera of patients with the respective infection showed that the DENV-3/III viruses can be effectively neutralised by sera of patients with DENV-3 infection (50% foci reduction neutralisation titres (FRNT50) > 1300). Sera of patients with DENV-1 infection (FRNT50 ⩾ 190), but not sera of patients with DENV-2 infection (FRNT50 ⩽ 50), were also able to neutralise the virus. These findings highlight the possibility that the pre-existing homotypic DENV-3 and the cross-reacting heterotypic DENV-1 antibody responses could play a role in mitigating a major outbreak involving DENV-3/III in the Klang Valley, Malaysia.
  7. Mitra SR, Tan PY, Amini F
    J Hum Nutr Diet, 2018 12;31(6):758-772.
    PMID: 30141234 DOI: 10.1111/jhn.12593
    BACKGROUND: Individual variations of obesity-related traits can be a consequence of dietary influence on gene variants.

    METHODS: This cross-sectional study aimed to evaluate (i) the effect of FTO rs9930506 on obesity and related parameters and (ii) the influence of diet on the above association in Malaysian adults. In total, 79 obese and 99 nonobese Malaysian adults were recruited.

    RESULTS: In comparison with Chinese and Malays, Indians had significantly higher waist circumference (P ≤ 0.001 and P = 0.016), waist-hip ratio (P = 0.001 and P < 0.001), body fat percentage (P = 0.001 and P = 0.042), fasting insulin (P = 0.001 and P = 0.001), homeostatic model assessment-insulin resistance (P = 0.001 and P = 0.001) and lower high-density lipoprotein-cholesterol levels (P < 0.001 and P < 0.001), respectively. Indians consumed significantly lower dietary cholesterol (P = 0.002), percentage energy from protein (P < 0.001) and higher fibre (P = 0.006) compared to the other two groups. Malaysian Indians expressed the highest risk allele frequency (G) of FTO rs9930506 compared to the Malays and the Chinese (P < 0.001). No significant association was found between FTO rs9930506 and obesity (dominant model). Risk allele carriers (G) consumed significantly lower vitamin E (P = 0.020) and had a higher fibre intake (P = 0.034) compared to the noncarriers (A). Gene-diet interaction analysis revealed that risk allele carriers (G) had lower high sensitivity C-reactive protein (hsCRP) levels with higher energy from protein (≥14% day-1 ; P = 0.049) and higher vitamin E (≥5.4 mg day-1 ; P = 0.038).

    CONCLUSIONS: The presence of the risk allele (G) of FTO rs9930506 was not associated with an increased risk of obesity. Malaysian Indians had a significantly higher frequency of the risk allele (G). Indian participants expressed higher atherogenic phenotypes compared to Chinese and Malays. FTO rs9930506 may interact with dietary protein and vitamin E and modulate hsCRP levels.

  8. Cheong AM, Tan CP, Nyam KL
    J Food Sci, 2018 Oct;83(10):2457-2465.
    PMID: 30178877 DOI: 10.1111/1750-3841.14332
    Kenaf seed oil-in-water nanoemulsions (NANO) stabilized by sodium caseinate (SC), beta-cyclodextrin (β-CD), and Tween 20 (T20) have been optimized and shown to improve in vitro bioaccessibility and physicochemical stability in the previous study. The main objective of this study was to evaluate the stability of bioactive compounds and antioxidants in the NANO during storage at different temperatures (4 °C, 25 °C, and 40 °C). An evaluation of the antioxidant activities of each emulsifier showed that SC had good scavenging capability with 97.6% ABTS radical scavenging activity. Therefore, SC which was used as one of the main emulsifiers could further enhanced the antioxidant activity of NANO. At week 8 of storage, NANO that stored at 4 °C had maintained the best bioactive compounds stability and antioxidant activities with 90% retention of vitamin E and 65% retention of phytosterols. These results suggested that 4 °C would be the most suitable storage temperature for NANO containing naturally present vitamin E and phytosterols. From the accelerated storage results at 40 °C, NANO containing vitamin E and phytosterols had maintained half of its initial concentration until week 4 and week 2 of storage, which is equivalent to 16 weeks and 8 weeks of storage at room temperature, respectively.

    PRACTICAL APPLICATION: The results of this study provide a better understanding on the stability of bioactive compounds and antioxidant activities in oil-in-water nanoemulsions that stabilized by similar ternary emulsifiers during storage at different temperatures. In addition, this study could be used as a predictive model to estimate the shelf life of bioactive compounds encapsulated in the form of nanoemulsions.

  9. Wong YP, Tan GC, Kumar R
    Neuropathology, 2018 Dec;38(6):619-623.
    PMID: 30187570 DOI: 10.1111/neup.12511
    Xanthomatous changes can be observed in various conditions including primary xanthomatosis that is linked to an underlying hypercholesterolemia and more commonly associated with secondary xanthomatous degenerative processes in neoplasm and chronic inflammation. Meningioma with extensive xanthomatous change is exceedingly rare. The presence of cholesterol clefts within this peculiar meningioma subtype has not been described. Herein, we report an unusual case of xanthomatous meningioma in an 83-year-old normolipidemic woman, who presented to us with worsening lower limb weakness and global aphasia. There was increasing evidence to suggest that the presence of xanthomatous changes in long-standing meningioma is merely a sequela of cellular degeneration rather than true metaplastic change as previously hypothesized. Hence, the diagnosis of "xanthomatous meningioma" in the metaplastic category should be revisited and considered as a distinct histological subtype. The possible histogenesis of such intriguing phenomenon is discussed with a review of the literature.
  10. Saedon NI, Pin Tan M, Frith J
    J Gerontol A Biol Sci Med Sci, 2020 01 01;75(1):117-122.
    PMID: 30169579 DOI: 10.1093/gerona/gly188
    BACKGROUND: Orthostatic hypotension (OH) is associated with increased risk of falls, cognitive impairment and death, as well as a reduced quality of life. Although it is presumed to be common in older people, estimates of its prevalence vary widely. This study aims to address this by pooling the results of epidemiological studies.

    METHODS: MEDLINE, EMBASE, PubMed, Web of Science, and ProQuest were searched. Studies were included if participants were more than 60 years, were set within the community or within long-term care and diagnosis was based on a postural drop in systolic blood pressure (BP) ≥20 mmHg or diastolic BP ≥10 mmHg. Data were extracted independently by two reviewers. Random and quality effects models were used for pooled analysis.

    RESULTS: Of 23,090 identified records, 20 studies were included for community-dwelling older people (n = 24,967) and six were included for older people in long-term settings (n = 2,694). There was substantial variation in methods used to identify OH with differing supine rest duration, frequency and timing of standing BP, measurement device, use of standing and tilt-tables and interpretation of the diagnostic drop in BP. The pooled prevalence of OH in community-dwelling older people was 22.2% (95% CI = 17, 28) and 23.9% (95% CI = 18.2, 30.1) in long-term settings. There was significant heterogeneity in both pooled results (I2 > 90%).

    CONCLUSIONS: OH is very common, affecting one in five community-dwelling older people and almost one in four older people in long-term care. There is great variability in methods used to identify OH.

  11. Ong SQ, Ahmad H, Tan EH
    Environ Entomol, 2018 12 07;47(6):1582-1585.
    PMID: 30165432 DOI: 10.1093/ee/nvy127
    Megaselia scalaris (Loew) (Diptera: Phoridae) provides great evidential value in estimating the postmortem interval (PMI) compared with other dipterans due to its common occurrence on human corpses both indoors and in concealed environments. Studies have focused on the effect of temperature, larval diet, and photoperiod on the development of the species; however, knowledge of M. scalaris development at different moisture levels is insufficient. This study aimed to investigate the effects of substrate moisture on the larval development time, pupal recovery, pupal weight, adult emergence, and adult head width of M. scalaris. The larvae were reared in five replicates on substrates with six moisture levels ranging from 50 to 90%. Larvae and puparia were sampled daily, and the collection time, number, and weight were recorded, measured, and then compared using multivariate analysis of variance with a post hoc least significant difference test. Larvae developed most quickly (3.75 ± 0.04 d) at 50% substrate moisture; the larvae were able to survive in extremely wet substrates (90% moisture), but the development time was significantly longer (6.48 ± 0.19 d). Moisture greatly influenced the pupation rate and adult emergence but showed a weak effect on the pupae weight and adult head width. Due to the significance of moisture on the development of M. scalaris, PMI estimation using M. scalaris with cadavers of different moisture content must be carefully conducted to avoid inaccuracy.
  12. Kho KL, Tan PE, Tay ST
    J Med Entomol, 2019 02 25;56(2):547-552.
    PMID: 30304529 DOI: 10.1093/jme/tjy168
    High seropositivity to Rickettsia conorii and Rickettsia felis has been reported in Malaysian indigenous community living in settlements adjacent to forest areas. The current study was conducted to determine the type and distribution of rickettsiae in feeding and questing ticks that were collected from a forest reserve area at Kuala Lompat in Pahang, Malaysia. Using PCR assays targeting citrate synthase (gltA), outer membrane protein A (ompA) and B (ompB) genes, rickettsiae were detected from approximately one-third of 98 ticks (mainly Dermacentor and Haemaphysalis spp.) collected from the forest reserve. BLAST analysis reveals the predominance of Rickettsia sp. RF2125 in both feeding and questing ticks and Rickettsia sp. TCM1 in the questing ticks. Sequences exhibiting close genetic relationship with Rickettsia raoultii, Rickettsia tamurae, Rickettsia heilongjiangensis, and Rickettsia asiatica were also detected from the ticks. This study highlights the diversity of rickettsial species and potential tick vectors which may contribute to the high seropositivity observed among the local communities.
  13. Low SK, Tan MC, Chin NL
    Ultrason Sonochem, 2018 Nov;48:64-70.
    PMID: 30080587 DOI: 10.1016/j.ultsonch.2018.05.024
    Ultrasound was applied simultaneously with adsorption process in most of the previous studies. However, this method is not practical to treat huge amounts of coloured wastewater effluent. In this study, the efficiency of ultrasound pre-treated peanut husk powder at different power levels (1.5-3.5 W) in dye adsorption with several conditions of initial dye concentration (20-100 mg/L), contact time (0.5-5 h), solution pH (2-8), and dosage (0.1-0.3 g) was studied and compared with ultrasound simultaneous adsorption process and the control. Adsorption efficiency of indirect ultrasound pre-treated peanut husk powder has increased 25.78%, 13.64% and 1.5% compared with the control, ultrasound simultaneous adsorption and direct ultrasound pre-treated sample respectively at 60 mg/L of initial dye concentration. Indirect ultrasound pre-treated sample at 3.5 W has achieved the highest adsorption efficiency of 89.96% at solution pH 8 and 94.83% at 0.3 g dose for 3 h. The surface feature and textural properties of samples were characterized by using scanning electron microscopy and surface characterization analyser. The result indicated that more porous structure was created on the ultrasound pre-treated sample at increasing power levels.
  14. Yam MF, Tan CS, Shibao R
    Hypertens Res, 2018 Oct;41(10):787-797.
    PMID: 30111856 DOI: 10.1038/s41440-018-0083-8
    Orthosiphon stamineus Benth. (Lambiaceae) is an important traditional plant for the treatment of hypertension. Previous studies have demonstrated that the sinensetin content in O. stamineus is correlated with its vasorelaxant activity. However, there is still very little information regarding the vasorelaxant effect of sinensetin due to a lack of scientific studies. Therefore, the present study was designed to investigate the underlying mechanism of action of sinensetin in vasorelaxation using an in vitro precontraction aortic ring assay. The changes in the tension of the aortic ring preparations were recorded using a force-displacement transducer and the PowerLab system. The mechanisms of the vasorelaxant effect of sinensetin were determined in the presence of antagonists. Sinensetin caused relaxation of the aortic ring precontracted with PE in the presence and absence of the endothelium and with potassium chloride in endothelium-intact aortic rings. In the presence of Nω-nitro-L-arginine methyl ester (nitric oxide synthase inhibitor), methylene blue (cyclic guanosine monophosphate lowering agent), ODQ (selective soluble guanylate cyclase inhibitor), indomethacin (a nonselective cyclooxygenase inhibitor), tetraethylammonium (nonselective calcium activator K+ channel blocker), 4-aminopyridine (voltage-dependent K+ channel blocker), barium chloride (inwardly rectifying Kir channel blocker), glibenclamide (nonspecific ATP-sensitive K+ channel blocker), atropine (muscarinic receptor blocker), or propranolol (β-adrenergic receptor blocker), the relaxation stimulated by sinensetin was significantly reduced. Sinensetin was also active in reducing Ca2+ release from the sarcoplasmic reticulum (via IP3R) and in blocking calcium channels (VOCC). The present study demonstrates the vasorelaxant effect of sinensetin, which involves the NO/sGC/cGMP and indomethacin pathways, calcium and potassium channels, and muscarinic and beta-adrenergic receptors.
  15. Ling Tan JS, Roberts CJ, Billa N
    Pharm Dev Technol, 2019 Apr;24(4):504-512.
    PMID: 30132723 DOI: 10.1080/10837450.2018.1515225
    This study describes the properties of an amphotericin B-containing mucoadhesive nanostructured lipid carrier (NLC), with the intent to maximize uptake within the gastrointestinal tract. We have reported previously that lipid nanoparticles can significantly improve the oral bioavailability of amphotericin B (AmpB). On the other hand, the aggregation state of AmpB within the NLC has been ascribed to some of the side effects resulting from IV administration. In the undissolved state, AmpB (UAmpB) exhibited the safer monomeric conformation in contrast to AmpB in the dissolved state (DAmpB), which was aggregated. Chitosan-coated NLC (ChiAmpB NLC) presented a slightly slower AmpB release profile as compared to the uncoated formulation, achieving 26.1% release in 5 hours. Furthermore, the ChiAmpB NLC formulation appeared to prevent the expulsion of AmpB upon exposure to simulated gastrointestinal pH media, whereby up to 63.9% of AmpB was retained in the NLC compared to 56.1% in the uncoated formulation. The ChiAmpB NLC demonstrated mucoadhesive properties in pH 5.8 and 6.8. Thus, the ChiAmpB NLC formulation is well-primed for pharmacokinetic studies to investigate whether delayed gastrointestinal transit may be exploited to improve the systemic bioavailability of AmpB, whilst simultaneously addressing the side-effect concerns of AmpB.
  16. Tan BL, Norhaizan ME, Chan LC
    Pharmaceutics, 2018 Oct 23;10(4).
    PMID: 30360519 DOI: 10.3390/pharmaceutics10040198
    Magnetic iron oxide nanoparticles are among the most useful metal nanoparticles in biomedical applications. A previous study had confirmed that phytic acid-chitosan-iron oxide nanocomposite (Phy-CS-MNP) exhibited antiproliferative activity towards human colorectal cancer (HT-29) cells. Hence, in this work, we explored the in vitro cytotoxicity activity and mechanistic action of Phy-CS-MNP nanocomposite in modulating gene and protein expression profiles in HT-29 cell lines. Cell cycle arrest and apoptosis were evaluated by NovoCyte Flow Cytometer. The mRNA changes (cyclin-dependent kinase 4 (Cdk4), vascular endothelial growth factor A (VEGFA), c-Jun N-terminal kinase 1 (JNK1), inducible nitric oxide synthase (iNOS), and matrix metallopeptidase 9 (MMP9)) and protein expression (nuclear factor-kappa B (NF-κB) and cytochrome c) were assessed by quantitative real-time polymerase chain reaction (PCR) and western blotting, respectively. The data from our study demonstrated that treatment with Phy-CS-MNP nanocomposite triggered apoptosis and G₀/G₁ cell cycle arrest. The transcriptional activity of JNK1 and iNOS was upregulated after treatment with 90 μg/mL Phy-CS-MNP nanocomposite. Our results suggested that Phy-CS-MNP nanocomposite induced apoptosis and cell cycle arrest via an intrinsic mitochondrial pathway through modulation of Bax and Bcl-2 and the release of cytochrome c from the mitochondria into the cytosol.
  17. Sabrina B, Tan KL, Johann FK, Andre D
    Med J Malaysia, 2018 08;73(4):255-256.
    PMID: 30121691 MyJurnal
    Ureteric and bladder injuries are uncommon, difficult to diagnose and rarely occur in isolation. Diagnosis is often delayed or missed at presentation. Therefore, high clinical suspicion and appropriate timing of computed tomography (CT) are of paramount importance. We report two cases (ureteropelvic junction avulsion and ruptured dome of bladder) whereby the presentations were subtle and would have been missed if not for high clinical suspicion. This article discusses the problems associated with these urologic injuries, as well as how to develop a high index of suspicion based on the pattern of anatomical disruption, mechanism of injury, physiological abnormality and comorbidity.
  18. Chew SC, Tan CP, Nyam KL
    J Food Sci, 2018 Sep;83(9):2288-2294.
    PMID: 30074623 DOI: 10.1111/1750-3841.14291
    Kenaf seed oil is prone to undergo oxidation due to its high content of unsaturated fatty acids, thus microencapsulation stands as an alternative to protect kenaf seed oil from the adverse environment. This study primarily aimed to evaluate the oxidative stability of microencapsulated refined kenaf seed oil (MRKSO) by the use of gum arabic, β-cyclodextrin, and sodium caseinate as the wall materials by spray drying. Bulk refined kenaf seed oil (BRKSO) and MRKSO were kept at 65 °C for 24 days to evaluate its oxidative stability, changes of tocopherol and tocotrienol contents, phytosterol content, and fatty acid profile. The results showed that the peroxide value, p-Anisidine value, and total oxidation value of BRKSO were significantly higher than the MRKSO at day 24. The total tocopherol and tocotrienol contents were reduced 66.1% and 56.8% in BRKSO and MRKSO, respectively, upon the storage. There was a reduction of 71.7% and 23.5% of phytosterol content in BRKSO and MRKSO, respectively, upon the storage. The degradation rate of polyunsaturated fatty acids in BRKSO was higher than that of MRKSO. This study showed that the current microencapsulation technique is a feasible way to retard the oxidation of kenaf seed oil.

    PRACTICAL APPLICATION: There is increasing research on the functional properties of crude kenaf seed oil, but the crude kenaf seed oil is not edible. This study offered in developing of microencapsulated refined kenaf seed oil by spray drying, which is suitable for food application. The microencapsulation of refined kenaf seed oil with healthier wall materials is beneficial in developing a diversity of functional food products and supplements.

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