Displaying publications 41 - 60 of 87 in total

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  1. Tnah LH, Lee SL, Lee CT, Ng KKS, Ng CH, Zawiah N
    3 Biotech, 2024 Jan;14(1):7.
    PMID: 38074292 DOI: 10.1007/s13205-023-03848-w
    With the rapid growth of the fruit industry worldwide, it is important to assess adulteration to ensure the authenticity and the safety of fruit products. The DNA barcoding approach offers a quick and accurate way of identifying and authenticating species. In this study, we developed reference DNA barcodes (rbcL, ITS2, and trnH-psbA) for 70 cultivated and wild tropical fruit species, representing 43 genera and 26 families. In terms of species recoverability, rbcL has a greater recoverability (100%) than ITS2 (95.7%) and trnH-psbA (88.6%). We evaluated the performance of these barcodes in species discrimination using similarity BLAST, phylogenetic tree, and barcoding gap analyses. The efficiency of rbcL, ITS2, and trnH-psbA in discriminating species was 80%, 100%, and 93.6%, respectively. We employed a multigene-tiered approach for species identification, with the rbcL region used for primary differentiation and ITS2 or trnH-psbA used for secondary differentiation. The two-locus barcodes rbcL + ITS2 and rbcL + trnH-psbA demonstrated robustness, achieving species discrimination rates of 100% and 94.3% respectively. Beyond the conventional species identification method based on plant morphology, the developed reference barcodes will aid the fruit agroindustry and trade, by making fruit-based product authentication possible.

    SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-023-03848-w.

  2. Danpanichkul P, Ng CH, Tan DJH, Wijarnpreecha K, Huang DQ, Noureddin M, et al.
    Clin Gastroenterol Hepatol, 2024 Sep;22(9):1947-1949.e3.
    PMID: 38428708 DOI: 10.1016/j.cgh.2024.02.011
    Alcohol is a substance that impacts premature mortality and morbidity.1 The liver is invariably subjected to the impact of alcohol, which can result in cirrhosis and cancer. Alcohol also has detrimental effects that extend beyond the liver. While traditionally associated with advanced age, emerging data reported a rising burden of cancers and alcohol-associated liver disease in the young.1-3 Thus, the primary objective was to evaluate the trend of alcohol-associated cirrhosis and cancer in young and middle-aged adults (aged 15-49) utilizing the Global Burden of Disease Study (GBD) 2019.4 We chose the age group less than 50 years old based on the definition of early-onset cancer and the inherent selection of the age group in the GBD database.4-6 The detailed methods are provided in the Supplementary Appendix. Briefly, data were sourced from population-based cancer registries, vital registration systems, or verbal autopsy studies. Verbal autopsy is a well-established approach for monitoring health, providing valuable information on mortality patterns and the reasons behind deaths in areas lacking robust medical death certification processes. The researchers employed the Cause of Death Ensemble model to estimate the burden linked to cancer and cirrhosis associated with alcohol use.
  3. Ng CH, Pathy NB, Taib NA, Ho GF, Mun KS, Rhodes A, et al.
    Asian Pac J Cancer Prev, 2014;15(18):7959-64.
    PMID: 25292095
    The significance of the single hormone receptor positive phenotype of breast cancer is still poorly understood. The use of hormone therapy has been found to be less effective for this type, which has a survival outcome midway between double positive and double negative phenotypes. The aim of this study was to investigate differences in patient and tumor characteristics and survival between double-receptor positive (ER+PR+), double receptor negative (ER-PR-) and single receptor positive (ER+PR- and ER-PR+) breast cancer in an Asian setting. A total of 1,992 patients with newly diagnosed stage I to IV breast cancer between 2003 and 2008, and where information on ER and PR were available, were included in this study. The majority of patients had ER+PR+ tumors (n=903: 45.3%), followed by 741 (37.2%) ER-PR-, 247 (12.4%) ER+PR-, and 101 (5.1%) ER-PR+ tumors. Using multivariate analysis, ER+PR- tumors were 2.4 times more likely to be grade 3 compared to ER+PR+ tumors. ER+PR- and ER-PR+ tumors were 82% and 86% respectively less likely to be grade 3 compared with ER-PR- tumors. ER-PR+ tumours were associated with younger age. There were no survival differences between patients with ER+PR+ and ER-PR+ tumors. However, ER+PR- tumors have poorer survival compared with ER+PR+ tumours. ER-PR- tumours had the worst survival. Adjuvant hormonal therapy with tamoxifen was found to have identical survival advantage in patients with ER+PR+ and ER-PR+ tumors whereas impact was slightly lower in patients with ER+PR- tumors. In conclusion, we found ER+PR- tumors to be more aggressive and have poorer survival when compared to ER+PR+ tumors, while patients with ER-PR+ tumours were younger, but had a similar survival to their counterparts with ER+PR+ tumours.
  4. Ng CH, Rullah K, Aluwi MF, Abas F, Lam KW, Ismail IS, et al.
    Molecules, 2014;19(8):11645-59.
    PMID: 25100256 DOI: 10.3390/molecules190811645
    The natural product molecule 2,4,6-trihydroxy-3-geranyl-acetophenone (tHGA) isolated from the medicinal plant Melicope ptelefolia was shown to exhibit potent lipoxygenase (LOX) inhibitory activity. It is known that LOX plays an important role in inflammatory response as it catalyzes the oxidation of unsaturated fatty acids, such as linoleic acid to form hydroperoxides. The search for selective LOX inhibitors may provide new therapeutic approach for inflammatory diseases. Herein, we report the synthesis of tHGA analogs using simple Friedel-Craft acylation and alkylation reactions with the aim of obtaining a better insight into the structure-activity relationships of the compounds. All the synthesized analogs showed potent soybean 15-LOX inhibitory activity in a dose-dependent manner (IC50 = 10.31-27.61 μM) where compound 3e was two-fold more active than tHGA. Molecular docking was then applied to reveal the important binding interactions of compound 3e in soybean 15-LOX binding site. The findings suggest that the presence of longer acyl bearing aliphatic chain (5Cs) and aromatic groups could significantly affect the enzymatic activity.
  5. Teh YC, Shaari NE, Taib NA, Ng CH, See MH, Tan GH, et al.
    Asian Pac J Cancer Prev, 2014;15(7):3163-7.
    PMID: 24815464
    BACKGROUND: Breast-conserving surgery (BCS) plus radiotherapy is equivalent to modified radical mastectomy (MRM) in terms of outcome. However there is wide variation in mastectomy rates dependent both on tumour and patient characteristics.

    OBJECTIVE: This study aimed to assess the determinants of surgery choice in Asian patients with early breast cancer in a middle-income country.

    MATERIALS AND METHODS: 184 patients with early breast cancer treated between Jan 2008 and Dec 2010 were recruited to complete a questionnaire. Chi-square test was used to analyze the association between surgery choice and demographic and tumour factors, surgeon recommendation, family member and partner opinions, fear of recurrence, avoidance of second surgery, fear of disfigurement, interference with sex life, fear of radiation and loss of femininity.

    RESULTS: 85 (46%) had BCS while 99 (54%) had mastectomy. Age >60, Chinese ethnicity, lower education level, and larger tumour size were significantly associated with mastectomy. Surgeon recommendation was important in surgery choice. Although both groups did not place much importance on interference with sex life, 14.1% of the BCS group felt it was very important compared to 5.1% in the mastectomy group and this was statistically significant. There was no statistical difference between the two groups in terms of the other factors. When analyzed by ethnicity, significantly more Malay and Indian women considered partner and family member opinions very important and were more concerned about loss of femininity compared to Chinese women. There were no statistical differences between the three ethnic groups in terms of the other factors.

    CONCLUSIONS: When counseling on surgical options, the surgeon has to take into account the ethnicity, social background and education level, age and reliance on partner and family members. Decision-making is usually a collective effort rather than just between the patient and surgeon, and involving the whole family into the process early is important.

  6. Tnah LH, Lee CT, Lee SL, Ng KK, Ng CH, Nurul-Farhanah Z, et al.
    Am J Bot, 2012 Nov;99(11):e431-3.
    PMID: 23108468 DOI: 10.3732/ajb.1200165
    Aggressive collections and trade activities in recent decades have resulted in heavy pressure on the natural stands of Aquilaria malaccensis and concerns over its long-term survival potential. To aid DNA profiling and assessment of its genetic diversity, microsatellite markers were developed for the species.
  7. Seng HL, Von ST, Tan KW, Maah MJ, Ng SW, Rahman RN, et al.
    Biometals, 2010 Feb;23(1):99-118.
    PMID: 19787298 DOI: 10.1007/s10534-009-9271-y
    Crystal structure analysis of the zinc complex establishes it as a distorted octahedral complex, bis(3-methylpicolinato-kappa(2) N,O)(2)(1,10-phenanthroline-kappa(2) N,N)-zinc(II) pentahydrate, [Zn(3-Me-pic)(2)(phen)]x5H(2)O. The trans-configuration of carbonyl oxygen atoms of the carboxylate moieties and orientation of the two planar picolinate ligands above and before the phen ligand plane seems to confer DNA sequence recognition to the complex. It cannot cleave DNA under hydrolytic condition but can slightly be activated by hydrogen peroxide or sodium ascorbate. Circular Dichroism and Fluorescence spectroscopic analysis of its interaction with various duplex polynucleotides reveals its binding mode as mainly intercalation. It shows distinct DNA sequence binding selectivity and the order of decreasing selectivity is ATAT > AATT > CGCG. Docking studies lead to the same conclusion on this sequence selectivity. It binds strongly with G-quadruplex with human tolemeric sequence 5'-AG(3)(T(2)AG(3))(3)-3', can inhibit topoisomerase I efficiently and is cytotoxic against MCF-7 cell line.
  8. Phua CE, Bustam AZ, Yusof MM, Saad M, Yip CH, Taib NA, et al.
    Asian Pac J Cancer Prev, 2012;13(9):4623-6.
    PMID: 23167391
    BACKGROUND: The risk of treatment-related death (TRD) and febrile neutropaenia (FN) with adjuvant taxane- based chemotherapy for early breast cancer is unknown in Malaysia despite its widespread usage in recent years. This study aims to determine these rates in patients treated in University Malaya Medical Centre (UMMC).

    PATIENTS AND METHODS: Patients who were treated with adjuvant taxane-based chemotherapy for early breast cancer stages I, II or III from 2007-2011 in UMMC were identified from our UMMC Breast Cancer Registry. The TRD and FN rates were then determined retrospectively from medical records. TRD was defined as death occurring during or within 30 days of completing chemotherapy as a consequence of the chemotherapy treatment. FN was defined as an oral temperature >38.5°C or two consecutive readings of >38.0°C for 2 hours and an absolute neutrophil count <0.5x109/L, or expected to fall below 0.5x109/L.

    RESULTS: A total of 622 patients received adjuvant chemotherapy during this period. Of these patients 209 (33.6%) received taxane-based chemotherapy. 4 taxane-based regimens were used namely the FEC-D, TC, TAC and AC-PCX regimens. The commonest regimen employed was the FEC-D regimen accounting for 79.9% of the patients. The FN rate was 10% and there was no TRD.

    CONCLUSION: Adjuvant taxane-based chemotherapy in UMMC for early breast cancer has a FN rate of 10%. Primary prophylactic G-CSF should be considered for patients with any additional risk factor for FN.

  9. Tan CS, Loh YC, Ch'ng YS, Ng CH, Yeap ZQ, Ahmad M, et al.
    J Ethnopharmacol, 2019 Mar 25;232:135-144.
    PMID: 30543913 DOI: 10.1016/j.jep.2018.12.014
    ETHNOPHARMACOLOGICAL RELEVANCE: Citrus reticulatae Pericarpium (Chen pi) was widely used as an important ingredient in the prescription of TCM to treat phlegm fluid retention type hypertension. Since Chen pi is involved in treatment as antihypertensive TCM formula, we have reasonable expectation in believing that it might possess vasorelaxant activity.

    AIM OF THE STUDY: This study is designed to investigate the vasorelaxant effect of Chen pi and to study its pharmacology effects.

    MATERIALS AND METHODS: The vasorelaxant effect of water extract of Chen pi (CRW) were evaluated on thoracic aortic rings isolated from Sprague Dawley rats. The fingerprint of Chen pi and the extracts were developed with quantification of hesperidin content by HPTLC.

    RESULTS: CRW exhibited the strongest vasorelaxant activity. CRW caused the relaxation of the phenylephrine pre-contracted aortic rings in the presence and absence of endothelium as well as in potassium chloride pre-contracted endothelium-intact aortic ring. The incubation of propranolol (β-adrenergic receptor blocker), atropine (muscarinic receptor blocker), Nω-nitro-L-arginine methyl ester (NO synthase inhibitor), ODQ (sGC inhibitor), indomethacin (COX inhibitor), 4-aminopyridine (KV blocker), barium chloride (Kir blocker), and glibenclamide (KATP blocker) significantly reduced the vasorelaxant effects of CRW. CRW was also found to be active in reducing Ca2+ releases from the sarcoplasmic reticulum and suppressing the voltage-operated calcium channels.

    CONCLUSION: The vasorelaxant effect of CRW on rat aorta involves NO/sGC, calcium and potassium channels, muscarinic and β-adrenergic receptors.

  10. Lee SL, Zakaria NF, Tnah LH, Ng CH, Ng KKS, Lee CT, et al.
    Forensic Sci Int Genet, 2022 Mar;57:102658.
    PMID: 34998185 DOI: 10.1016/j.fsigen.2021.102658
    Aquilaria malaccensis (Thymelaeaceae) is the main source of high-grade agarwood in Southeast Asia. Aggressive collections and trade activities over the past decades have put great pressure on the natural stands and raised concerns over the long-term survival potential of A. malaccensis. Tracking and authentication of agarwood require method with a high degree of accuracy. Therefore, this study aimed to develop DNA databases of A. malaccensis as the tracking tools at species, population and individual levels for forensic identification and chain of custody certification. Using two cpDNA (rbcL and matK) and an rDNA (ITS2) markers, species identification database of Aquilaria was developed to distinguish A. malaccensis from A. hirta, A. microcarpa, A. beccariana, A. crassna, A. sinensis and A. rostrata. In addition, based on 35 populations of A. malaccensis throughout Peninsular Malaysia, cpDNA haplotype and STR allele frequency databases were developed for population and individual identification. A haplotype distribution map based on 29 haplotypes derived from seven cpDNA showed that the A. malaccensis in Peninsular Malaysia can be associated to Kedah-Perak and Kelantan-Johor regions. Similarly, genetic relatedness and Bayesian clustering analyses based on 10 STR markers also divided the 35 populations into two main genetic clusters, corresponding to Kedah-Perak and Kelantan-Johor regions. The STR allele frequency databases were established and characterized according to these two regions. To determine the performance of the STR allele frequency databases for population identification, independent self-assignment tests showed that the percentage of individuals correctly assigned into the origin population was 93.88% in Kedah-Perak and 90.29% in Kelantan-Johor. For the STR allele frequency databases to be used for individual identification, conservativeness tests showed that the θ should be adjusted to 0.250 and 0.200 in the Kedah-Perak and Kelantan-Johor databases, respectively. To ensure consistency in allele calling for the dinucleotide repeat loci across different electrophoretic platforms or laboratories, allelic ladders have been developed for the 10 STR loci. Two case studies are presented of how these databases were used to track A. malaccensis to the origin population and stump. These databases are ready to be used to provide admissible forensic evidence for legal proceedings against the illegal harvesters of agarwood and for agarwood certification to meet the consumer country regulations.
  11. Lai JW, Maah MJ, Tan KW, Sarip R, Lim YAL, Ganguly R, et al.
    Malar J, 2022 Dec 17;21(1):386.
    PMID: 36528584 DOI: 10.1186/s12936-022-04406-0
    BACKGROUND: Malaria remains one of the most virulent and deadliest parasitic disease in the world, particularly in Africa and Southeast Asia. Widespread occurrence of artemisinin-resistant Plasmodium falciparum strains from the Greater Mekong Subregion is alarming. This hinders the national economies, as well as being a major drawback in the effective control and elimination of malaria worldwide. Clearly, an effective anti-malarial drug is urgently needed.

    METHODS: The dinuclear and mononuclear copper(II) and zinc(II) complexes were synthesized in ethanolic solution and characterized by various physical measurements (FTIR, CHN elemental analysis, solubility, ESI-MS, UV-Visible, conductivity and magnetic moment, and NMR). X-ray crystal structure of the dicopper(II) complex was determined. The in vitro haemolytic activities of these metal complexes were evaluated spectroscopically on B+ blood while the anti-malarial potency was performed in vitro on blood stage drug-sensitive Plasmodium falciparum 3D7 (Pf3D7) and artemisinin-resistant Plasmodium falciparum IPC5202 (Pf5202) with fluorescence dye. Mode of action of metal complexes were conducted to determine the formation of reactive oxygen species using PNDA and DCFH-DA dyes, JC-1 depolarization of mitochondrial membrane potential, malarial 20S proteasome inhibition with parasite lysate, and morphological studies using Giemsa and Hoechst stains.

    RESULTS: Copper(II) complexes showed anti-malarial potency against both Pf3D7 and Pf5202 in sub-micromolar to micromolar range. The zinc(II) complexes were effective against Pf3D7 with excellent therapeutic index but encountered total resistance against Pf5202. Among the four, the dinuclear copper(II) complex was the most potent against both strains. The zinc(II) complexes caused no haemolysis of RBC while copper(II) complexes induced increased haemolysis with increasing concentration. Further mechanistic studies of both copper(II) complexes on both Pf3D7 and Pf5202 strains showed induction of ROS, 20S malarial proteasome inhibition, loss of mitochondrial membrane potential and morphological features indicative of apoptosis.

    CONCLUSION: The dinuclear [Cu(phen)-4,4'-bipy-Cu(phen)](NO3)4 is highly potent and can overcome the total drug-resistance of Pf5202 towards chloroquine and artemisinin. The other three copper(II) and zinc(II) complexes were only effective towards the drug-sensitive Pf3D7, with the latter causing no haemolysis of RBC. Their mode of action involves multiple targets.

  12. Chan SW, Mahmoud VL, Wang X, Teoh ML, Loh KM, Ng CH, et al.
    PLoS One, 2024;19(11):e0310770.
    PMID: 39509364 DOI: 10.1371/journal.pone.0310770
    Agarwood essential oil (AEO) has gained attention from healthcare industries due to its numerous pharmacological properties. However, a comprehensive understanding of the chemical composition and its cytotoxic property is lacking. The objective of this study was to investigate the chemical profile as well as the cytotoxic concentration range of AEO derived from Aquilaria sinensis agarwood. Gas chromatography-mass spectrometry (GC-MS) was employed to identify the AEO components. Results showed that sesquiterpenes and sesquiterpenoids constitute 95.85% of the AEO. Among the major compounds identified are allo-aromadendrene (13.04%), dihydro-eudesmol (8.81%), α-eudesmol (8.48%), bulnesol (7.63%), τ-cadinol (4.95%), dehydrofukinone (3.83%), valerenol (3.54%), cis-nerolidol (2.75%), agarospirol (2.72%), dehydrojinkoh-eremol (2.53%), selina-3,11-dien-9-al (2.36%), guaiol (2.12%) and caryophyllene oxide (2.0%). The presence of volatile quality marker compounds such as 10-epi-ϒ-eudesmol, aromadendrane, β-agarofuran, α-agarofuran, γ-eudesmol, agarospirol and guaiol, with no contaminants detected, indicates that the extracted AEO is of high purity. Interestingly, the AEO displayed moderate to high toxicity in brine shrimp lethality test (BLST). All studied tumor cell lines (MDA-MB-231, HepG2, B16F10) exhibited varying degrees of sensitivity to AEO, which resulted in time and dose-dependent reduction of cell proliferation. Moreover, flow cytometry analysis revealed that AEO could induce apoptosis in treated HepG2 cells. Our findings showed that AEO contains bioactive components that may be exploited in future studies for the development of anti-cancer therapeutics.
  13. Ng CH, Wang WS, Chong KV, Win YF, Neo KE, Lee HB, et al.
    Dalton Trans, 2013 Jul 28;42(28):10233-43.
    PMID: 23728518 DOI: 10.1039/c3dt50884f
    Chiral enantiomers [Cu(phen)(L-threo)(H2O)]NO3 1 and [Cu(phen)(D-threo)(H2O)]NO3 2 (threo = threoninate) underwent aldol-type condensation with formaldehyde, with retention of chirality, to yield their respective enantiomeric ternary copper(II) complexes, viz. L- and D-[Cu(phen)(5MeOCA)(H2O)]NO3·xH2O (3 and 4; phen = 1,10-phenanthroline; 5MeOCA = 5-methyloxazolidine-4-carboxylate; x = 0-3) respectively. These chiral complexes were characterized by FTIR, elemental analysis, circular dichroism, UV-Visible spectroscopy, fluorescence spectroscopy (FL), molar conductivity measurement, ESI-MS and X-ray crystallography. Analysis of restriction enzyme inhibition by these four complexes revealed modulation of DNA binding selectivity by the type of ligand, ligand modification and chirality. Their interaction with bovine serum albumin was investigated by FL and electronic spectroscopy. With the aid of the crystal structure of BSA, spectroscopic evidence suggested their binding at the cavity containing Trp134 with numerous Tyr residues in subdomain IA. The products were more antiproliferative than cisplatin against cancer cell lines HK-1, MCF-7, HCT116, HSC-2 and C666-1 except HL-60, and were selective towards nasopharyngeal cancer HK-1 cells over normal NP69 cells of the same organ type.
  14. Seng HL, Wang WS, Kong SM, Alan Ong HK, Win YF, Raja Abd Rahman RN, et al.
    Biometals, 2012 Oct;25(5):1061-81.
    PMID: 22836829 DOI: 10.1007/s10534-012-9572-4
    A series of ternary copper(II)-1,10-phenanthroline complexes with glycine and methylated glycine derivatives, [Cu(phen)(aa)(H(2)O)]NO(3)·xH(2)O 1-4 (amino acid (aa): glycine (gly), 1; DL: -alanine (DL: -ala), 2; 2,2-dimethylglycine (C-dmg), 3; sarcosine (sar), 4), were synthesized and characterized by FTIR, elemental analysis, electrospray ionization-mass spectra (ESI-MS), UV-visible spectroscopy and molar conductivity measurement. The determined X-ray crystallographic structures of 2 and 3 show each to consist of distorted square pyramidal [Cu(phen)(aa)(H(2)O)](+) cation, a nitrate counter anion, and with or without lattice water, similar to previously reported structure of [Cu(phen)(gly)(H(2)O)]NO(3)·1½H(2)O. It is found that 1-4 exist as 1:1 electrolytes in aqueous solution, and the cationic copper(II) complexes are at least stable up to 24 h. Positive-ion ESI-MS spectra show existence of only undissociated [Cu(phen)(aa)](+) species. Electron paramagnetic resonance, gel electrophoresis, fluorescence quenching, and restriction enzyme inhibition assay were used to study the binding interaction, binding affinity and selectivity of these complexes for various types of B-form DNA duplexes and G-quadruplex. All complexes can bind selectively to DNA by intercalation and electrostatic forces, and inhibit topoisomerase I. The effect of the methyl substituents of the coordinated amino acid in the above complexes on these biological properties are presented and discussed. The IC(50) values (24 h) of 1-4 for nasopharyngeal cancer cell line HK1 are in the range 2.2-5.2 μM while the corresponding values for normal cell line NP69 are greater than 13.0 μM. All complexes, at 5 μM, induced 41-60 % apoptotic cell death in HK1 cells but no significant cell death in NP69 cells.
  15. Ng KKS, Lee SL, Tnah LH, Nurul-Farhanah Z, Ng CH, Lee CT, et al.
    Forensic Sci Int Genet, 2016 07;23:197-209.
    PMID: 27213560 DOI: 10.1016/j.fsigen.2016.05.002
    Illegal logging and smuggling of Gonystylus bancanus (Thymelaeaceae) poses a serious threat to this fragile valuable peat swamp timber species. Using G. bancanus as a case study, DNA markers were used to develop identification databases at the species, population and individual level. The species level database for Gonystylus comprised of an rDNA (ITS2) and two cpDNA (trnH-psbA and trnL) markers based on a 20 Gonystylus species database. When concatenated, taxonomic species recognition was achieved with a resolution of 90% (18 out of the 20 species). In addition, based on 17 natural populations of G. bancanus throughout West (Peninsular Malaysia) and East (Sabah and Sarawak) Malaysia, population and individual identification databases were developed using cpDNA and STR markers respectively. A haplotype distribution map for Malaysia was generated using six cpDNA markers, resulting in 12 unique multilocus haplotypes, from 24 informative intraspecific variable sites. These unique haplotypes suggest a clear genetic structuring of West and East regions. A simulation procedure based on the composition of the samples was used to test whether a suspected sample conformed to a given regional origin. Overall, the observed type I and II errors of the databases showed good concordance with the predicted 5% threshold which indicates that the databases were useful in revealing provenance and establishing conformity of samples from West and East Malaysia. Sixteen STRs were used to develop the DNA profiling databases for individual identification. Bayesian clustering analyses divided the 17 populations into two main genetic clusters, corresponding to the regions of West and East Malaysia. Population substructuring (K=2) was observed within each region. After removal of bias resulting from sampling effects and population subdivision, conservativeness tests showed that the West and East Malaysia databases were conservative. This suggests that both databases can be used independently for random match probability estimation within respective regions. The reliability of the databases was further determined by independent self-assignment tests based on the likelihood of each individual's multilocus genotype occurring in each identified population, genetic cluster and region with an average percentage of correctly assigned individuals of 54.80%, 99.60% and 100% respectively. Thus, after appropriate validation, the genetic identification databases developed for G. bancanus in this study could support forensic applications and help safeguard this valuable species into the future.
  16. Wong HS, Subramaniam S, Alias Z, Taib NA, Ho GF, Ng CH, et al.
    Medicine (Baltimore), 2015 Feb;94(8):e593.
    PMID: 25715267 DOI: 10.1097/MD.0000000000000593
    Web-based prognostication tools may provide a simple and economically feasible option to aid prognostication and selection of chemotherapy in early breast cancers. We validated PREDICT, a free online breast cancer prognostication and treatment benefit tool, in a resource-limited setting. All 1480 patients who underwent complete surgical treatment for stages I to III breast cancer from 1998 to 2006 were identified from the prospective breast cancer registry of University Malaya Medical Centre, Kuala Lumpur, Malaysia. Calibration was evaluated by comparing the model-predicted overall survival (OS) with patients' actual OS. Model discrimination was tested using receiver-operating characteristic (ROC) analysis. Median age at diagnosis was 50 years. The median tumor size at presentation was 3 cm and 54% of patients had lymph node-negative disease. About 55% of women had estrogen receptor-positive breast cancer. Overall, the model-predicted 5 and 10-year OS was 86.3% and 77.5%, respectively, whereas the observed 5 and 10-year OS was 87.6% (difference: -1.3%) and 74.2% (difference: 3.3%), respectively; P values for goodness-of-fit test were 0.18 and 0.12, respectively. The program was accurate in most subgroups of patients, but significantly overestimated survival in patients aged <40 years, and in those receiving neoadjuvant chemotherapy. PREDICT performed well in terms of discrimination; areas under ROC curve were 0.78 (95% confidence interval [CI]: 0.74-0.81) and 0.73 (95% CI: 0.68-0.78) for 5 and 10-year OS, respectively. Based on its accurate performance in this study, PREDICT may be clinically useful in prognosticating women with breast cancer and personalizing breast cancer treatment in resource-limited settings.
  17. Azman A, Ng KK, Ng CH, Lee CT, Tnah LH, Zakaria NF, et al.
    Sci Rep, 2020 11 05;10(1):19112.
    PMID: 33154411 DOI: 10.1038/s41598-020-76092-4
    Worldwide, many mangrove species are experiencing significant population declines, including Rhizophora apiculata, which is one of the most widespread and economically important species in tropical Asia. In Malaysia, there has been an alarming decline in R. apiculata populations driven primarily by anthropogenic activities. However, the lack of genetic and demographic information on this species has hampered local efforts to conserve it. To address these gaps, we generated novel genetic information for R. apiculata, based on 1,120 samples collected from 39 natural populations in Peninsular Malaysia. We investigated its genetic diversity and genetic structure with 19 transcriptome and three nuclear microsatellite markers. Our analyses revealed a low genetic diversity (mean He: 0.352) with significant genetic differentiation (FST: 0.315) among populations of R. apiculata. Approximately two-third of the populations showed significant excess of homozygotes, indicating persistent inbreeding which might be due to the decrease in population size or fragmentation. From the cluster analyses, the populations investigated were divided into two distinct clusters, comprising the west and east coasts of Peninsular Malaysia. The western cluster was further divided into two sub-clusters with one of the sub-clusters showing strong admixture pattern that harbours high levels of genetic diversity, thus deserving high priority for conservation.
  18. Chin LF, Kong SM, Seng HL, Khoo KS, Vikneswaran R, Teoh SG, et al.
    J Inorg Biochem, 2011 Mar;105(3):339-47.
    PMID: 21421121 DOI: 10.1016/j.jinorgbio.2010.11.018
    The synthesis and characterization of two cobalt(II) complexes, Co(phen)(ma)Cl 1 and Co(ma)(2)(phen) 2, (phen=1,10-phenanthroline, ma(-)=maltolate or 2-methyl-4-oxo-4H-pyran-3-olate) are reported herein. The complexes have been characterized by FTIR, CHN analysis, fluorescence spectroscopy, UV-visible spectroscopy, conductivity measurement and X-ray crystallography. The number of chelated maltolate ligands seems to influence their DNA recognition, topoisomerase I inhibition and antiproliferative properties.
  19. Seng HL, Ong HK, Rahman RN, Yamin BM, Tiekink ER, Tan KW, et al.
    J Inorg Biochem, 2008 Nov;102(11):1997-2011.
    PMID: 18778856 DOI: 10.1016/j.jinorgbio.2008.07.015
    The binding selectivity of the M(phen)(edda) (M=Cu, Co, Ni, Zn; phen=1,10-phenanthroline, edda=ethylenediaminediacetic acid) complexes towards ds(CG)(6), ds(AT)(6) and ds(CGCGAATTCGCG) B-form oligonucleotide duplexes were studied by CD spectroscopy and molecular modeling. The binding mode is intercalation and there is selectivity towards AT-sequence and stacking preference for A/A parallel or diagonal adjacent base steps in their intercalation. The nucleolytic properties of these complexes were investigated and the factors affecting the extent of cleavage were determined to be: concentration of complex, the nature of metal(II) ion, type of buffer, pH of buffer, incubation time, incubation temperature, and the presence of hydrogen peroxide or ascorbic acid as exogenous reagents. The fluorescence property of these complexes and its origin were also investigated. The crystal structure of the Zn(phen)(edda) complex is reported in which the zinc atom displays a distorted trans-N(4)O(2) octahedral geometry; the crystal packing features double layers of complex molecules held together by extensive hydrogen bonding that inter-digitate with adjacent double layers via pi...pi interactions between 1,10-phenanthroline residues. The structure is compared with that of the recently described copper(II) analogue and, with the latter, included in molecular modeling.
  20. Lee KY, Ng YL, Wang WS, Ng PY, Chan CW, Lai JW, et al.
    Dalton Trans, 2019 Apr 09;48(15):4987-4999.
    PMID: 30916098 DOI: 10.1039/c9dt00506d
    Chiral enantiomers [Cu(phen)(l-ser)(H2O)]NO31 and [Cu(phen)(d-ser)(H2O)]NO32 (ser = serinato) underwent aldol-type condensation with formaldehyde, with retention of chirality, to yield their respective enantiomeric ternary copper(ii) complexes, viz. l- and d-[Cu(phen)(OCA)(H2O)]NO3·xH2O (3 and 4; phen = 1,10-phenanthroline; OCA = oxazolidine-4-carboxylate; x = 1/2, 0-2) respectively. These chiral complexes were characterized by FTIR, elemental analysis, circular dichroism, UV-visible spectroscopy, fluorescence spectroscopy (FL), molar conductivity measurement, ESI-MS and X-ray crystallography. The crystal structures of 1 and 3 showed both the cationic complexes to have a square pyramidal geometry. These complexes were about nine fold more potent than cisplatin against metastatic MDA-MB-231 breast cancer cells, inducing apoptotic cell death via ROS generation and a massive drop in mitochondrial membrane potential. The results of monitoring EZH1, EZH2 and H3K27me3 revealed that the mode of action of 1-4 also involved the downregulation of EZH2 and it seemed to be independent of the H3K27me3 status.
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