Displaying publications 1 - 20 of 41 in total

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  1. Govindaraju, Kayatri, Lee, Mei Kee, Mbaki, Yvonne, Ting, Kang Nee
    MyJurnal
    The general notion of activation of Gq-protein coupled receptors (GPCR) involves the mobilisation of stored and extracellular calcium and leads to smooth muscle tissue contraction. The aim of this study was to investigate the involvement of calcium mediated contractions in vascular and airway smooth muscles. Using standard organ bath procedures, aortic and tracheal rings were obtained from 6 to 8 week-old male Sprague Dawley rats. To activate the Gq protein receptors, phenylephrine (PE), an α1-adrenoceptor agonist, and carbachol, a M3 cholinoceptor agonist was added to baths containing the aortic and tracheal rings, respectively. The maximum response (Emax) to PE was reduced from 158.8 ± 11.8% (n=6) to 62.5 ± 12.4 % (n=8) upon removal of extracellular calcium in Krebs-Ringer solution. Maximal response to PE was also suppressed in the presence of nifedipine, a L-type Ca2+ channel inhibitor, (70.3 ± 11 %, n=8) and SKF96365, a canonical transient receptor potential cation channel inhibitor, (26.7 ± 13.2 %, n=5) when the influx of extracellular calcium was blocked. Removal of stored calcium also attenuated the PE contraction (p0.05). From these observations, we conclude that the role of stored and extracellular calcium in Gq protein activation is not the same across different types of smooth muscle tissues.
  2. Li-Yin Pang, Shola Sonagara, Oreoluwatomide Oduwole, Christopher Gibbins, Ting Kang Nee
    MyJurnal
    Over the past few decades, microplastics have become increasingly ubiquitous in the environment and now contaminate the bodies of many living organisms, including humans. Microplastics, as defined here, are plastics within the size range 0.1 μm and 5 mm and are a worrying form of pollution due to public health concerns. This mini-review aims to summarise the route of entry of microplastics into humans and explore the potential detrimental health effects of microplastics. Trophic transfer is an important pathway for microplastic to be transferred across different groups of organisms, with ingestion is regarded as one of the major routes of exposure for humans. Other pathways include inhalation and dermal contact. The health consequences of microplastics manifest because these materials can translocate into the circulatory system and accumulate in the lungs, liver, kidney, and even brain, regardless of the route of entry. Health effects include gastrointestinal disturbances such as inflammation and gut microbiota disruption, respiratory conditions, neurotoxicity and potential cancers. Overall, while it is apparent that microplastics are causing adverse effects on different biological groups and ecosystems, current research is largely focused on marine organisms and aquaculture. Therefore, more studies are needed to investigate specific effects in mammalian cells and tissues, with more long-term epidemiological studies needed on human population considered to be at high-risk due to socioeconomic or other circumstance. Knowledge of the toxicity and long-term health impacts of microplastics is currently limited and requires urgent attention.
  3. Li-Yin Pang, Chon-Seng Tan, Szu-Ting Ng, Kuan-Hon Lim, Sue-Mian Then, Ting Kang Nee
    MyJurnal
    Ophiocordyceps sinensis is one of the most sought-after medicinal fungi used to treat various medical conditions such as respiratory diseases, liver and kidney dysfunctions. In China, it is widely used for alleviation of frequent urination where patients treated with O. sinensis have shown improvement in nocturia, which is the most common symptom of overactive bladder (OAB). Many studies have reported its anticancer, anti-inflammatory, anti-oxidative, hypoglycaemic and vasorelaxation properties. These properties are attributable to the presence of bioactive components such as polysaccharides, proteins and nucleosides. This mini-review highlights the medicinal potential of O. sinensis in alleviating OAB, which is a debilitating condition with a profound impact on the quality of life in a high proportion of older people. Four possible mechanisms of action of O. sinensis are suggested. Firstly, the relaxation of bladder smooth muscle through calcium dynamic, production of nitric acid (NO) and adenosine triphosphate (ATP). A second mechanism proposed is through the suppression of micturition reflex. The unequivocal properties of O. sinensis as anti-inflammatory and anti-oxidant, are two other plausible explanations, as both chronic inflammation and accumulation of oxidative stress molecules are associated with OAB exacerbation. With the recent success in cultivation of O. sinensis and the positive results from toxicity studies, a better understanding of its pharmacological actions can be further substantiated, including its use for relieving OAB.
  4. Ting KN, Stratton-Powell DM, Anderson C
    Pharm World Sci, 2010 Jun;32(3):339-42.
    PMID: 20336371 DOI: 10.1007/s11096-010-9382-0
    OBJECTIVES: To investigate community pharmacists' knowledge, attitudes and views on adverse drug reaction (ADR) reporting. Setting Seven community pharmacies in Malaysia.

    METHOD: Structured interviews with community pharmacists. Informed consent was obtained and interviews were audio-recorded and transcribed verbatim.

    MAIN OUTCOME MEASURES: Content analysis of themes on awareness of ADR reporting, reporting activities, attitudes and views on patient reporting.

    RESULTS: All pharmacists claimed to have some knowledge of a reporting system but only one had submitted a report directly to the regulatory authority. Despite the low level of reporting activities, all participants agreed that it was part of their professional obligation to report an ADR. Most participants were not aware of the direct patient reporting scheme and were skeptical about its success. Lack of awareness and patients' limited knowledge about their medications were viewed as barriers to patient reporting. Local attitudinal issues including pharmacists' attitude towards ADR reporting were described as possible contributing factors.

    CONCLUSION: Community pharmacists have an important role in reporting ADRs. Many Malaysian patients are still perceived to be ill-informed of their medications, an important determinant to the success of patient reporting. There is a need for further training about ADRs and ADR reporting for health professionals and further education for patients.

  5. Low BY, Ting KN, Lee MK
    Int J Pharm Pract, 2023 Apr 10;31(2):261-265.
    PMID: 36534990 DOI: 10.1093/ijpp/riac101
    OBJECTIVE: To assess the knowledge, attitude and practice of community pharmacists (CP) towards household pharmaceutical waste disposal.

    METHODS: All pharmacists attending the Malaysian Community Pharmacy Guild event held in-person were invited to self-administer a web-based survey.

    KEY FINDINGS: The response rate was 61% (168/276). Overall, community pharmacists have mixed knowledge (mean ± SD: 5.89 ± 1.38) and positive attitude (mean ± SD: 9.58 ± 0.81) towards household pharmaceutical waste disposal. However, few community pharmacists (18/168, 10.7%) have promotional materials encouraging safe medication disposal in their pharmacies.

    CONCLUSIONS: Community pharmacists do not proactively promote safe household pharmaceutical waste disposal to mitigate pharmaceutical pollutants entering the environment although they have satisfactory knowledge and attitude.

  6. Santiago C, Lim KH, Loh HS, Ting KN
    Molecules, 2015 Mar 10;20(3):4473-82.
    PMID: 25764489 DOI: 10.3390/molecules20034473
    Formation of biofilms is a major factor for nosocomial infections associated with methicillin-resistance Staphylococcus aureus (MRSA). This study was carried out to determine the ability of a fraction, F-10, derived from the plant Duabanga grandiflora to inhibit MRSA biofilm formation. Inhibition of biofilm production and microtiter attachment assays were employed to study the anti-biofilm activity of F-10, while latex agglutination test was performed to study the influence of F-10 on penicillin-binding protein 2a (PBP2a) level in MRSA biofilm. PBP2a is a protein that confers resistance to beta-lactam antibiotics. The results showed that, F-10 at minimum inhibitory concentration (MIC, 0.75 mg/mL) inhibited biofilm production by 66.10%; inhibited cell-surface attachment by more than 95%; and a reduced PBP2a level in the MRSA biofilm was observed. Although ampicilin was more effective in inhibiting biofilm production (MIC of 0.05 mg/mL, 84.49%) compared to F-10, the antibiotic was less effective in preventing cell-surface attachment. A higher level of PBP2a was detected in ampicillin-treated MRSA showing the development of further resistance in these colonies. This study has shown that F-10 possesses anti-biofilm activity, which can be attributed to its ability to reduce cell-surface attachment and attenuate the level of PBP2a that we postulated to play a crucial role in mediating biofilm formation.
  7. Islahudin F, Pleass RJ, Avery SV, Ting KN
    J Antimicrob Chemother, 2012 Oct;67(10):2501-5.
    PMID: 22763566 DOI: 10.1093/jac/dks253
    OBJECTIVES: Recent work with the yeast model revealed that the antiprotozoal drug quinine competes with tryptophan for uptake via a common transport protein, causing cellular tryptophan starvation. In the present work, it was hypothesized that similar interactions may occur in malaria patients receiving quinine therapy.

    PATIENTS AND METHODS: A direct observational study was conducted in which plasma levels of drug and amino acids (tryptophan, tyrosine and phenylalanine) were monitored during quinine treatment of malaria patients with Plasmodium falciparum infections.

    RESULTS: Consistent with competition for uptake from plasma into cells, plasma tryptophan and tyrosine levels increased ≥2-fold during quinine therapy. Plasma quinine levels in individual plasma samples were significantly and positively correlated with tryptophan and tyrosine in the same samples. Control studies indicated no effect on phenylalanine. Chloroquine treatment of Plasmodium vivax-infected patients did not affect plasma tryptophan or tyrosine. During quinine treatment, plasma tryptophan was significantly lower (and quinine significantly higher) in patients experiencing adverse drug reactions.

    CONCLUSIONS: Plasma quinine levels during therapy are related to patient tryptophan and tyrosine levels, and these interactions can determine patient responses to quinine. The study also highlights the potential for extrapolating insights directly from the yeast model to human malaria patients.

  8. Clarke G, Ting KN, Wiart C, Fry J
    Antioxidants (Basel), 2013;2(1):1-10.
    PMID: 26787618 DOI: 10.3390/antiox2010001
    Extracts of plants from the Malaysian rainforest and other fragile habitats are being researched intensively for identification of beneficial biological actions, with assessment of antioxidant behavior being a common component of such assessments. A number of tests for antioxidant behavior are used, with the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reduction activity potential (FRAP) assays often being used in parallel, and also with measurement of total phenolics content (TPC) as a surrogate marker for antioxidant capacity. The present study investigated the possible redundancy in using all three assays to determine antioxidant capacity in 92 extracts obtained from 27 plants from the Malaysian rainforest. The results demonstrated that the assays displayed a high (R ≥ 0.82) and significant (P < 0.0001) correlation with one another, indicating a high level of redundancy if all three assays are used in parallel. This appears to be a waste of potentially valuable plant extracts. Because of problems with the FRAP assay relating to color interference and variable rates of reaction point, the DPPH assay is the preferred assay in preliminary screening of extracts of plants from the Malaysian rainforest.
  9. Santiago C, Lim KH, Loh HS, Ting KN
    PMID: 25880167 DOI: 10.1186/s12906-015-0615-6
    Formation of biofilm is known to enhance the virulence of methicillin-resistance Staphylococcus aureus (MRSA), which is associated with persistent infections in hospital settings. The biofilm layer essentially forms a protective barrier encapsulating the bacterial colony and thus reduces the effectiveness of chemotherapeutics. We have isolated 9EA-FC-B bioactive fraction from Acalypha wilkesiana Müll. Arg. that reverses ampicillin resistant in MRSA through inhibition of the antibiotic resistant protein, penicillin-binding protein 2a (PBP2a). In this study, we aimed to investigate the effects of 9EA-FC-B on MRSA biofilm forming capacity.
  10. Chen HL, Gibbins CN, Selvam SB, Ting KN
    Environ Pollut, 2021 Nov 15;289:117895.
    PMID: 34364115 DOI: 10.1016/j.envpol.2021.117895
    Microplastic pollution is widely recognised as a global issue, posing risks to natural ecosystems and human health. The combination of rapid industrial and urban development and relatively limited environmental regulation in many tropical countries may increase the amount of microplastic entering rivers, but basic data on contamination levels are lacking. This is especially the case in tropical South East Asian countries. In this paper, the abundance, composition and spatio-temporal variation of microplastic in the Langat River, Malaysia, were assessed, and the relationship between microplastic concentration and river discharge was investigated. Water samples were collected over a 12-month period from 8 sampling sites on the Langat, extending from forested to heavily urbanised and industrial areas. All 508 water samples collected over this period contained microplastic; mean concentration across all sites and times was 4.39 particles/L but extended up to 90.00 particles/L in some urban tributaries. Most microplastics were secondary in origin, and dominated by fibres. Microplastic counts correlated directly with river discharge, and counts increased and decreased in response to changes in flow. A time-integrated assessment of the microplastic load conveyed by the Langat suggested that the river is typically (50 % of the time) delivering around 5 billion particles per day to the ocean. The positive correlation between the concentration of microplastics and suspended sediments in the Langat suggested that continuously logging turbidity sensors could be used to provide better estimates of microplastic loads and improve assessment of human and ecological health risks.
  11. Chen HL, Selvam SB, Ting KN, Gibbins CN
    Environ Monit Assess, 2023 Jan 18;195(2):307.
    PMID: 36652034 DOI: 10.1007/s10661-022-10856-5
    Recent increase in awareness of the extent of microplastic contamination in marine and freshwater systems has heightened concerns over the ecological and human health risks of this ubiquitous material. Assessing risks posed by microplastic in freshwater systems requires sampling to establish contamination levels, but standard sampling protocols have yet to be established. An important question is whether sampling and assessment should focus on microplastic concentrations in the water or the amount deposited on the bed. On three dates, five replicated water and bed sediment samples were collected from each of the eight sites along the upper reach of the Semenyih River, Malaysia. Microplastics were found in all 160 samples, with mean concentrations of 3.12 ± 2.49 particles/L in river water and 6027.39 ± 16,585.87 particles/m2 deposited on the surface of riverbed sediments. Fibres were the dominant type of microplastic in all samples, but fragments made up a greater proportion of the material on the bed than in the water. Within-site variability in microplastic abundance was high for both water and bed sediments, and very often greater than between-site variability. Patterns suggest that microplastic accumulation on the bed is spatially variable, and single samples are therefore inadequate for assessing bed contamination levels at a site. Sites with the highest mean concentrations in samples of water were not those with the highest concentrations on the bed, indicating that monitoring based only on water samples may not provide a good picture of either relative or absolute bed contamination levels, nor the risks posed to benthic organisms.
  12. Chen HL, Selvam SB, Ting KN, Gibbins CN
    Environ Sci Pollut Res Int, 2021 Oct;28(39):54222-54237.
    PMID: 34386926 DOI: 10.1007/s11356-021-15826-x
    Plastics are synthetic polymers known for their outstanding durability and versatility, and have replaced traditional materials in many applications. Unfortunately, their unique traits ensure that they pose a major threat to the environment. While literature on freshwater microplastic contamination has grown over the recent years, research undertaken in rapidly developing countries, where plastic production and use are increasing dramatically, has lagged behind that in other parts of the world. In the South East Asia (SEA) region, basic information on levels of contamination is very limited and, as a consequence, the risk to human and ecological health remains hard to assess. This review synthesises what is currently known about microplastic contamination of freshwater ecosystems in SEA, with a particular focus on Malaysia. The review 1) summarises published studies that have assessed levels of contamination in freshwater systems in SEA, 2) discusses key sources and transport pathways of microplastic in freshwaters, 3) outlines what is known of the impacts of microplastic on freshwater organisms, and 4) identifies key knowledge gaps related to our understanding of the transport, fate and effects of microplastic.
  13. Nge CE, Gan CY, Lim KH, Ting KN, Low YY, Kam TS
    Org. Lett., 2014 Dec 19;16(24):6330-3.
    PMID: 25454201 DOI: 10.1021/ol503072g
    Two new indole alkaloids characterized by previously unencountered natural product skeletons, viz., criofolinine (1), incorporating a pyrroloazepine motif within a pentacyclic ring system, and vernavosine (2, isolated as its ethyl ether derivative 3, which on hydrolysis regenerated the putative precursor alkaloid 2), incorporating a pyridopyrimidine moiety embedded within a pentacyclic carbon framework, were isolated from a Malayan Tabernaemontana species. The structures and absolute configuration of these alkaloids were determined on the basis of NMR and MS analysis and confirmed by X-ray diffraction analysis.
  14. Lim SW, Loh HS, Ting KN, Bradshaw TD, Zeenathul NA
    Biomed Pharmacother, 2014 Oct;68(8):1105-15.
    PMID: 25456851 DOI: 10.1016/j.biopha.2014.10.006
    The pure vitamin isomer, β-tocotrienol has the least abundance among the other vitamin E isomers that are present in numerous plants. Hence, it is very scarcely studied for its bioactivity. In this study, the antiproliferative effects and primary apoptotic mechanisms of β-tocotrienol on human lung adenocarcinoma A549 and glioblastoma U87MG cells were investigated. It was evidenced that β-tocotrienol had inhibited the growth of both A549 (GI50=1.38±0.334μM) and U87MG (GI50=2.53±0.604μM) cells at rather low concentrations. Cancer cells incubated with β-tocotrienol were also found to exhibit hallmarks of apoptotic morphologies including membrane blebbing, chromatin condensation and formation of apoptotic bodies. The apoptotic properties of β-tocotrienol in both A549 and U87MG cells were the results of its capability to induce significant (P<0.05) double-strand DNA breaks (DSBs) without involving single-strand DNA breaks (SSBs). β-Tocotrienol is said to induce activation of caspase-8 in both A549 and U87MG cells guided by no activation when caspase-8 inhibitor, z-IETD-fmk was added. Besides, disruption on the mitochondrial membrane permeability of the cells in a concentration- and time-dependent manner had occurred. The induction of apoptosis by β-tocotrienol in A549 and U87MG cells was confirmed to involve both the death-receptor mediated and mitochondria-dependent apoptotic pathways. These findings could potentiate the palm oil derived β-tocotrienol to serve as a new anticancer agent for treating human lung and brain cancers.
  15. Lim SW, Loh HS, Ting KN, Bradshaw TD, Zeenathul NA
    PMID: 25480449 DOI: 10.1186/1472-6882-14-469
    Tocotrienols, especially the gamma isomer was discovered to possess cytotoxic effects associated with the induction of apoptosis in numerous cancers. Individual tocotrienol isomers are believed to induce dissimilar apoptotic mechanisms in different cancer types. This study was aimed to compare the cytotoxic potency of alpha-, gamma- and delta-tocotrienols, and to explore their resultant apoptotic mechanisms in human lung adenocarcinoma A549 and glioblastoma U87MG cells which are scarcely researched.
  16. Santiago C, Pang EL, Lim KH, Loh HS, Ting KN
    Biomed Res Int, 2014;2014:965348.
    PMID: 25101303 DOI: 10.1155/2014/965348
    The inhibitory activity of a semipure fraction from the plant, Acalypha wilkesiana assigned as 9EA-FC-B, alone and in combination with ampicillin, was studied against methicillin-resistant Staphylococcus aureus (MRSA). In addition, effects of the combination treatment on PBP2a expression were investigated. Microdilution assay was used to determine the minimal inhibitory concentrations (MIC). Synergistic effects of 9EA-FC-B with ampicillin were determined using the fractional inhibitory concentration (FIC) index and kinetic growth curve assay. Western blot experiments were carried out to study the PBP2a expression in treated MRSA cultures. The results showed a synergistic effect between ampicillin and 9EA-FC-B treatment with the lowest FIC index of 0.19 (synergism ≤ 0.5). The presence of 9EA-FC-B reduced the MIC of ampicillin from 50 to 1.56 μg mL(-1). When ampicillin and 9EA-FC-B were combined at subinhibitory level, the kinetic growth curves were suppressed. The antibacterial effect of 9EA-FC-B and ampicillin was shown to be synergistic. The synergism is due the ability of 9EA-FC-B to suppress the activity of PBP2a, thus restoring the susceptibility of MRSA to ampicillin. Corilagin was postulated to be the constituent responsible for the synergistic activity showed by 9EA-FC-B.
  17. Othman M, Loh HS, Wiart C, Khoo TJ, Lim KH, Ting KN
    J Microbiol Methods, 2011 Feb;84(2):161-6.
    PMID: 21094190 DOI: 10.1016/j.mimet.2010.11.008
    The search for antimicrobial agents from plants has been a growing interest in the last few decades. However, results generated from many of these studies cannot be directly compared due to the absence of standardization in particular antimicrobial methods employed. The need for established methods with consistent results for the evaluation of antimicrobial activities from plant extracts has been proposed by many researchers. Nevertheless, there are still many studies reported in the literature describing different methodologies. The aim of this study was to find optimal methods to give consistent quantitative antimicrobial results for studying plant extracts. Three different agar-based assays (pour plate disc diffusion (PPDD), streak plate disc diffusion (SPDD) and well-in agar (WA)) and one broth-based (turbidometric (TB)) assay were used in this study. Extracts from two plant species (Duabanga grandiflora and Acalypha wilkesiana) were tested on two bacterial species, namely Escherichia coli and Staphylococcus aureus. Amongst the agar-based assays, PPDD produced the most reproducible results. TB was able to show the inhibitory effects of the test samples on the growth kinetic of the bacteria including plant extracts with low polarity. We propose that both agar- (i.e PPDD) and broth-based assays should be employed when assessing the antimicrobial activity of plant crude extracts.
  18. Gnanasan S, Ting KN, Wong KT, Mohd Ali S, Muttalif AR, Anderson C
    Int J Clin Pharm, 2011 Feb;33(1):44-52.
    PMID: 21365392 DOI: 10.1007/s11096-010-9452-3
    OBJECTIVE: To assess the feasibility of providing a pharmacist-led pharmaceutical care service to patients with tuberculosis and diabetes mellitus.

    SETTING: The study was conducted at a tertiary hospital in the northern region of Peninsular Malaysia. Methods Action research methodology was used.

    MAIN OUTCOME MEASURE: Pharmaceutical care issues.

    RESULTS: The prevalence of diabetes mellitus among newly diagnosed tuberculosis patients was 15% (53/352). Out of 53 patients identified, 35 participated in the study. Patients' ages ranged between 29 and 73 years (mean of 52 ± 10 years). The male: female ratio was 1.7:1. Pharmaceutical care issues identified by pharmacists were nonadherence, uncontrolled diabetes mellitus, adverse drug reactions and individual patient's medication related problems. Pharmacists were able to intervene and resolve some of the pharmaceutical care issues.

    CONCLUSION: Pharmacists played an important role in integrating the provision of care for tuberculosis and diabetes mellitus by providing individualised pharmaceutical care management. There still remains a need to address logistic barriers that impinged on the ability to conduct the pharmaceutical care service to its full potential.

  19. Santiago C, Pang EL, Lim KH, Loh HS, Ting KN
    PMID: 26060128 DOI: 10.1186/s12906-015-0699-z
    The inhibition of penicillin-binding protein 2a (PBP2a) is a promising solution in overcoming resistance of methicillin resistance Staphylococcus aureus (MRSA). A potential approach in achieving this is by combining natural product with currently available antibiotics to restore the activity as well as to amplify the therapeutic ability of the drugs. We studied inhibition effects of a bioactive fraction, F-10 (isolated from the leaves of Duabanga grandiflora) alone and in combination with a beta-lactam drug, ampicillin on MRSA growth and expression of PBP2a. Additionally, phytochemical analysis was conducted on F-10 to identify the classes of phytochemicals present.
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