Displaying publications 1 - 20 of 167 in total

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  1. Firdaus-Raih M, Hashim NHF, Bharudin I, Abu Bakar MF, Huang KK, Alias H, et al.
    PLoS One, 2018;13(1):e0189947.
    PMID: 29385175 DOI: 10.1371/journal.pone.0189947
    Extremely low temperatures present various challenges to life that include ice formation and effects on metabolic capacity. Psyhcrophilic microorganisms typically have an array of mechanisms to enable survival in cold temperatures. In this study, we sequenced and analysed the genome of a psychrophilic yeast isolated in the Antarctic region, Glaciozyma antarctica. The genome annotation identified 7857 protein coding sequences. From the genome sequence analysis we were able to identify genes that encoded for proteins known to be associated with cold survival, in addition to annotating genes that are unique to G. antarctica. For genes that are known to be involved in cold adaptation such as anti-freeze proteins (AFPs), our gene expression analysis revealed that they were differentially transcribed over time and in response to different temperatures. This indicated the presence of an array of adaptation systems that can respond to a changing but persistent cold environment. We were also able to validate the activity of all the AFPs annotated where the recombinant AFPs demonstrated anti-freeze capacity. This work is an important foundation for further collective exploration into psychrophilic microbiology where among other potential, the genes unique to this species may represent a pool of novel mechanisms for cold survival.
  2. Cheong HC, Lee CYQ, Cheok YY, Shankar EM, Sabet NS, Tan GMY, et al.
    Immunobiology, 2019 01;224(1):34-41.
    PMID: 30477893 DOI: 10.1016/j.imbio.2018.10.010
    BACKGROUND: Persistent inflammation caused by Chlamydia trachomatis in the female genital compartment represents one of the major causes of pelvic inflammatory disease (PID), ectopic pregnancy and infertility in females. Here, we examined the pro-inflammatory cytokine response following stimulation with three different types of C. trachomatis antigens, viz. chlamydial protease-like factor (CPAF), heat shock protein 60 (HSP60) and major outer membrane protein (MOMP).

    METHODS: A total of 19 patients with genital C. trachomatis infection and 10 age-matched healthy controls were recruited for the study. Peripheral blood mononuclear cells (PBMCs) isolated from genital C. trachomatis-infected females were cultured in the presence of CPAF, HSP60 and MOMP antigens, and cytokines were measured by ELISA assay.

    RESULTS: We reported that pro-inflammatory cytokines (TNF-α, IL-1β and IL-6) were robustly secreted following antigenic exposure. Notably, CPAP and MOMP were more potent in triggering IL-1β, as compared to HSP60. Elevated levels of the proinflammatory cytokines were also noted in the samples infected with plasmid-bearing C. trachomatis as compared to those infected with plasmid-free strains.

    CONCLUSIONS: Our study highlights distinct ability of chlamydial antigens in triggering pro-inflammatory response in the host immune cells.

  3. Cheong HC, Yap PSX, Chong CW, Cheok YY, Lee CYQ, Tan GMY, et al.
    PLoS One, 2019;14(11):e0224658.
    PMID: 31738795 DOI: 10.1371/journal.pone.0224658
    The cervical microbiota constitutes an important protective barrier against the invasion of pathogenic microorganisms. A disruption of microbiota within the cervical milieu has been suggested to be a driving factor of sexually transmitted infections. These include Chlamydia trachomatis which frequently causes serious reproductive sequelae such as infertility in women. In this study, we profiled the cervical microbial composition of a population of 70 reproductive-age Malaysian women; among which 40 (57.1%) were diagnosed with genital C. trachomatis infection, and 30 (42.8%) without C. trachomatis infection. Our findings showed a distinct compositional difference between the cervical microbiota of C. trachomatis-infected subjects and subjects without C. trachomatis infection. Specifically, significant elevations of mostly strict and facultative anaerobes such as Streptococcus, Megasphaera, Prevotella, and Veillonella in the cervical microbiota of C. trachomatis-positive women were detected. The results from the current study highlights an interaction of C. trachomatis with the environmental microbiome in the endocervical region.
  4. Yeow TC, Wong WF, Sabet NS, Sulaiman S, Shahhosseini F, Tan GM, et al.
    BMC Microbiol, 2016 Mar 18;16:45.
    PMID: 26987367 DOI: 10.1186/s12866-016-0671-1
    BACKGROUND: The 7.5 kb cryptic plasmid of Chlamydia trachomatis has been shown to be a virulence factor in animal models, but its significance in humans still remains unknown. The aim of this study was to investigate the prevalence and potential involvement of the C. trachomatis cryptic plasmid in causing various clinical manifestations; including infertility, reproductive tract disintegrity, menstrual disorder, and polycystic ovarian syndrome (PCOS) among genital C. trachomatis-infected patients.
    RESULTS:A tot l of 180 female patients of child bearing age (mean 30.9 years old, IQR:27-35) with gynecological complications and subfertility issues, who visited Obstetrics and Gynecology clinics in Kuala Lumpur, Malaysia were recruited for the study. Prevalence of genital chlamydial infection among these patients was alarmingly high at 51.1% (92/180). Of the 92 chlamydia-infected patients, 93.5% (86/92) were infected with plasmid-bearing (+) C. trachomatis while the remaining 6.5% (6/92) were caused by the plasmid-free (-) variant. Our data showed that genital C. trachomatis infection was associated with infertility issues, inflammation in the reproductive tract (mucopurulent cervicitis or endometriosis), irregular menstrual cycles and polycystic ovarian syndrome (PCOS). However, no statistical significance was detected among patients with plasmid (+) versus plasmid (-) C. trachomatis infection. Interestingly, plasmid (+) C. trachomatis was detected in all patients with PCOS, and the plasmid copy numbers were significantly higher among PCOS patients, relative to non-PCOS patients.
    CONCLUSION: Our findings show a high incidence of C. trachomatis infection among women with infertility or gynecological problems in Malaysia. However, due to the low number of plasmid (-) C. trachomatis cases, a significant role of the plasmid in causing virulence in human requires further investigation of a larger cohort.
    KEYWORDS: Chlamydia trachomatis; Infertility; Plasmid; Reproductive system disorders
    Study site: Obstetrics and Gynecology clinic, University Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia
  5. Salleh RM, Kuan G, Aziz MNA, Rahim MRA, Rahayu T, Sulaiman S, et al.
    Nutrients, 2021 May 24;13(6).
    PMID: 34073684 DOI: 10.3390/nu13061783
    BACKGROUND: Reports of probiotic consumption on athletes' performance are debatable due to their equivocal results. There is a need for more evidence on the effects of probiotic intake on psychological state and fitness level. Thus, this study determined the effects of daily probiotic consumption on competitive anxiety, perceived stress and mood among university badminton players, besides their fitness like aerobic capacity, strength, speed, leg power and agility.

    METHODS: Thirty university badminton players aged from 19 to 22 years old were randomly divided equally into two groups, where the probiotic group (PG; n = 15) received a drink that contained Lactobacillus casei Shirota (3 × 1010 CFU) and placebo group (CG; n = 15) a placebo drink for six weeks. Anxiety, stress and mood levels were determined using the CSAI-2R, PSS and BRUMS questionnaires, respectively. Fitness levels were measured using by subjecting the players to 20-m shuttle runs (aerobic capacity), handgrips (muscular strength), vertical jumps (leg power), 40-m dash (speed) and T-test (agility). The Student's t-test (p < 0.05) was used to determine the differences between PG and CG players.

    RESULTS: After six weeks, the anxiety and stress levels of PG players significantly decreased by 16% (p < 0.001) and 20% (p < 0.001), respectively, but there were no significant changes detected in CG players. Supplementation of probiotics also improved aerobic capacity in PG players by 5.9% (p < 0.001) but did not influence the speed, strength, leg power and agility.

    CONCLUSIONS: Probiotics supplementation showed improved aerobic capacity and relieve anxiety and stress. However, further studies need to be carried out to determine the mechanisms through which probiotic intake produces these effects.

  6. Azis RS, Sulaiman S, Ibrahim IR, Zakaria A, Hassan J, Muda NNC, et al.
    Nanoscale Res Lett, 2018 May 23;13(1):160.
    PMID: 29796949 DOI: 10.1186/s11671-018-2562-x
    Synthesis of nanocrystalline strontium ferrite (SrFe12O19) via sol-gel is sensitive to its modification parameters. Therefore, in this study, an attempt of regulating the pH as a sol-gel modification parameter during preparation of SrFe12O19 nanoparticles sintered at a low sintering temperature of 900 °C has been presented. The relationship of varying pH (pH 0 to 8) on structural, microstructures, and magnetic behaviors of SrFe12O19 nanoparticles were characterized by X-ray diffraction (XRD), field emission scanning microscope (FESEM), and vibrating sample magnetometer (VSM). Varying the pH of precursor exhibited a strong effect on the sintered density, crystal structure and magnetic properties of the SrFe12O19 nanoparticles. As the pH is 0, the SrFe12O19 produced relatively largest density, saturation magnetization, Ms, and coercivity, Hc, at a low sintering temperature of 900 °C. The grain size of SrFe12O19 is obtained in the range of 73.6 to 133.3 nm. The porosity of the sample affected the density and the magnetic properties of the SrFe12O19 ferrite. It is suggested that the low-temperature sintered SrFe12O19 at pH 0 displayed Ms of 44.19 emu/g and Hc of 6403.6 Oe, possessing a significant potential for applying in low-temperature co-fired ceramic permanent magnet.
  7. Tan KK, Zulkifle NI, Abd-Jamil J, Sulaiman S, Yaacob CN, Azizan NS, et al.
    Infect Genet Evol, 2017 Oct;54:271-275.
    PMID: 28698156 DOI: 10.1016/j.meegid.2017.07.008
    Dengue is hyperendemic in most of Southeast Asia. In this region, all four dengue virus serotypes are persistently present. Major dengue outbreak cycle occurs in a cyclical pattern involving the different dengue virus serotypes. In Malaysia, since the 1980s, the major outbreak cycles have involved dengue virus type 3 (DENV3), dengue virus type 1 (DENV1) and dengue virus type 2 (DENV2), occurring in that order (DENV3/DENV1/DENV2). Only limited information on the DENV3 cycles, however, have been described. In the current study, we examined the major outbreak cycle involving DENV3 using data from 1985 to 2016. We examined the genetic diversity of DENV3 isolates obtained during the period when DENV3 was the dominant serotype and during the inter-dominant transmission period. Results obtained suggest that the typical DENV3/DENV1/DENV2 cyclical outbreak cycle in Malaysia has recently been disrupted. The last recorded major outbreak cycle involving DENV3 occurred in 2002, and the expected major outbreak cycle involving DENV3 in 2006-2012 did not materialize. DENV genome analyses revealed that DENV3 genotype II (DENV3/II) was the predominant DENV3 genotype (67%-100%) recovered between 1987 and 2002. DENV3 genotype I (DENV3/I) emerged in 2002 followed by the introduction of DENV3 genotype III (DENV3/III) in 2008. These newly emerged DENV3 genotypes replaced DENV3/II, but there was no major upsurge of DENV3 cases that accompanied the emergence of these viruses. DENV3 remained in the background of DENV1 and DENV2 until now. Virus genome sequence analysis suggested that intrinsic differences within the different dengue virus genotypes could have influenced the transmission efficiency of DENV3. Further studies and continuous monitoring of the virus are needed for better understanding of the DENV transmission dynamics in hyperendemic regions.
  8. Hassan J, Toh TH, Sivapunniam SK, Hasim R, Ghazali NF, Sulaiman S, et al.
    Pediatr Infect Dis J, 2021 08 01;40(8):774-781.
    PMID: 34250977 DOI: 10.1097/INF.0000000000003164
    BACKGROUND: Incorporating dengue vaccination within existing vaccination programs could help improve dengue vaccine coverage. We assessed the immunogenicity and safety of a quadrivalent human papillomavirus (HPV) vaccine administered concomitantly or sequentially with a tetravalent dengue vaccine (CYD-TDV) in healthy children 9-13 years of age in Malaysia.

    METHODS: In this phase IIIb, open-label, multicenter study (NCT02993757), participants were randomized 1:1 to receive 3 CYD-TDV doses 6 months apart and 2 doses of quadrivalent HPV vaccine concomitantly with, or 1 month before (sequentially), the first 2 CYD-TDV doses. Only baseline dengue-seropositive participants received the 3 doses. Antibody levels were measured at baseline and 28 days after each injection using an enzyme-linked immunosorbent assay for HPV-6, -9, -16 and -18, and the 50% plaque reduction neutralization test for the 4 dengue serotypes; immunogenicity results are presented for baseline dengue-seropositive participants. Safety was assessed throughout the study for all participants.

    RESULTS: At baseline, 197 of 528 (37.3%) randomized participants were dengue-seropositive [n = 109 (concomitant group) and n = 88 (sequential group)]. After the last HPV vaccine dose, antibody titers for HPV among baseline dengue-seropositive participants were similar between treatment groups, with between-group titer ratios close to 1 for HPV-6 and 0.8 for HPV-11, -16, and -18. After CYD-TDV dose 3, dengue antibody titers were similar between treatment groups for all serotypes [between-group ratios ranged from 0.783 (serotype 2) to 1.07 (serotype 4)]. No safety concerns were identified.

    CONCLUSIONS: The immunogenicity and safety profiles of CYD-TDV and quadrivalent HPV vaccines were unaffected when administered concomitantly or sequentially in dengue-seropositive children.

  9. Zaharim WN, Ahmad SNA, Sulaiman S, Rozak H, Hasan Baseri DF, Mohamad Rosli NA, et al.
    ACS Omega, 2021 Nov 09;6(44):29641-29650.
    PMID: 34778635 DOI: 10.1021/acsomega.1c03956
    Density functional theory method at the B3LYP/6-31G level was used to determine the structure of 12mer single-strand guanine oligomers. The length and width of the optimized structure are 38.7 and 18.2 Å, respectively, and the observed high-resolution transmission electron microscopy image of the 12mer single-strand guanine sample shows similar oligomer dimensions with the calculated ones. Both HOMO and LUMO are significantly delocalized, and the calculated HOMO-LUMO gap is 3.31 eV. A total of 96 muonium trapping sites at C2, C4, C5, C6, C8, N3, N7, and O6 were investigated. All 12 C8 sites have lower energy than the other 84 sites and are clustered in the energy-muon hyperfine coupling constant scatter plot. The calculated muon hyperfine coupling constant at C8 sites range from 384.6 to 481.1 MHz, and the corresponding estimated ALC-μSR resonance for |ΔM| = 1 range from 1.419 to 1.775 T.
  10. Cheong HC, Cheok YY, Chan YT, Tang TF, Sulaiman S, Looi CY, et al.
    BMC Microbiol, 2023 Mar 04;23(1):58.
    PMID: 36870960 DOI: 10.1186/s12866-023-02802-3
    BACKGROUND: Genital Chlamydia trachomatis infection is the most common bacterial sexual transmitted disease that causes severe complications including pelvic inflammatory disease, ectopic pregnancy, and infertility in females. The Pgp3 protein encoded by C. trachomatis plasmid has been speculated to be an important player in chlamydial pathogenesis. However, the precise function of this protein is unknown and thus remains to be thoroughly investigated.

    METHODS: In this study, we synthesized Pgp3 protein for in vitro stimulation in the Hela cervical carcinoma cells.

    RESULTS AND CONCLUSION: We showed that Pgp3 induced prominent expression of host inflammatory cytokine genes including interleukin-6 (IL-6), IL-8, tumor necrosis factor alpha-induced protein 3 (TNFAIP3), and chemokine C-X-C motif ligand 1 (CXCL1), implying a possible role of Pgp3 in modulating the inflammatory reaction in the host.

  11. Chan YT, Cheok YY, Cheong HC, Tan GMY, Seow SR, Tang TF, et al.
    Immunol Cell Biol, 2023 Apr;101(4):305-320.
    PMID: 36658328 DOI: 10.1111/imcb.12621
    Genital Chlamydia trachomatis infection remains a major health issue as it causes severe complications including pelvic inflammatory disease, ectopic pregnancy and infertility in females as a result of infection-associated chronic inflammation. Podoplanin, a transmembrane receptor, has been previously reported on inflammatory macrophages. Thus, strategies that specifically target podoplanin might be able to reduce local inflammation. This study investigated the expression level and function of podoplanin in a C. trachomatis infection model. C57BL/6 mice infected with the mouse pathogen Chlamydia muridarum were examined intermittently from days 1 to 60 using flow cytometry analysis. Percentages of conventional macrophages (CD11b+ CD11c- F4/80+ ) versus inflammatory macrophages (CD11b+ CD11c+ F4/80+ ), and the expression of podoplanin in these cells were investigated. Subsequently, a podoplanin-knockout RAW264.7 cell was used to evaluate the function of podoplanin in C. trachomatis infection. Our findings demonstrated an increased CD11b+ cell volume in the spleen at day 9 after the infection, with augmented podoplanin expression, especially among the inflammatory macrophages. A large number of podoplanin-expressing macrophages were detected in the genital tract of C. muridarum-infected mice. Furthermore, analysis of the C. trachomatis-infected patients demonstrated a higher percentage of podoplanin-expressing monocytes than that in the noninfected controls. Using an in vitro infection in a transwell migration assay, we identified that macrophages deficient in podoplanin displayed defective migratory function toward C. trachomatis-infected HeLa 229 cells. Lastly, using immunoprecipitation-mass spectrometry method, we identified two potential podoplanin interacting proteins, namely, Cofilin 1 and Talin 1 actin-binding proteins. The present study reports a role of podoplanin in directing macrophage migration to the chlamydial infection site. Our results suggest a potential for reducing inflammation in individuals with chronic chlamydial infections by targeting podoplanin.
  12. Muhammad H, Gomes-Carneiro MR, Poça KS, De-Oliveira AC, Afzan A, Sulaiman SA, et al.
    J Ethnopharmacol, 2011 Jan 27;133(2):647-53.
    PMID: 21044879 DOI: 10.1016/j.jep.2010.10.055
    Orthosiphon stamineus, Benth, also known as Misai Kucing in Malaysia and Java tea in Indonesia, is traditionally used in Southeastern Asia to treat kidney dysfunctions, diabetes, gout and several other illnesses. Recent studies of Orthosiphon stamineus pharmacological profile have revealed antioxidant properties and other potentially useful biological activities thereby lending some scientific support to its use in folk medicine. So far the genotoxicity of Orthosiphon stamineus extracts has not been evaluated. In this study the genotoxic potential of Orthosiphon stamineus aqueous extract was investigated by the Salmonella/microsome mutation assay and the mouse bone marrow micronucleus test.
  13. Mohd Azamai ES, Sulaiman S, Mohd Habib SH, Looi ML, Das S, Abdul Hamid NA, et al.
    J Zhejiang Univ Sci B, 2009 Jan;10(1):14-21.
    PMID: 19198018 DOI: 10.1631/jzus.B0820168
    Chlorella vulgaris (CV) has been reported to have antioxidant and anticancer properties. We evaluated the effect of CV on apoptotic regulator protein expression in liver cancer-induced rats. Male Wistar rats (200~250 g) were divided into eight groups: control group (normal diet), CDE group (choline deficient diet supplemented with ethionine in drinking water to induce hepatocarcinogenesis), CV groups with three different doses of CV (50, 150, and 300 mg/kg body weight), and CDE groups treated with different doses of CV (50, 150, and 300 mg/kg body weight). Rats were sacrificed at various weeks and liver tissues were embedded in paraffin blocks for immunohistochemistry studies. CV, at increasing doses, decreased the expression of anti-apoptotic protein, Bcl-2, but increased the expression of pro-apoptotic protein, caspase 8, in CDE rats, which was correlated with decreased hepatocytes proliferation and increased apoptosis as determined by bromodeoxy-uridine (BrdU) labeling and terminal deoxynucleotidyl transferase mediated dUTP nick-end labeling (TUNEL) assay, respectively. Our study shows that CV has definite chemopreventive effect by inducing apoptosis via decreasing the expression of Bcl-2 and increasing the expression of caspase 8 in hepatocarcinogenesis-induced rats.
  14. Ab-Rahman HA, Wong PF, Rahim H, Abd-Jamil J, Tan KK, Sulaiman S, et al.
    Springerplus, 2015;4:665.
    PMID: 26558168 DOI: 10.1186/s40064-015-1463-z
    INTRODUCTION: HPS is a potentially life-threatening histiocytic disorder that has been described in various viral infections including dengue. Its involvement in severe and fatal dengue is probably more common but is presently under recognized.
    CASE DESCRIPTION: A 38-year-old female was admitted after 5 days of fever. She was deeply jaundiced, leukopenic and thrombocytopenic. Marked elevation of transaminases, hyperbilirubinemia and hypoalbuminemia were observed. She had deranged INR values and prolonged aPTT accompanied with hypofibrinogenemia. She also had splenomegaly. She was positive for dengue IgM. Five days later she became polyuric and CT brain image showed gross generalized cerebral edema. Her conditions deteriorated by day 9, became confused with GCS of 9/15. Her BMAT showed minimal histiocytes. Her serum ferritin level peaked at 13,670.00 µg/mL and her sCD163 and sCD25 values were markedly elevated at 4750.00 ng/mL and 4191.00 pg/mL, respectively. She succumbed to the disease on day 10 and examination of her tissues showed the presence of dengue virus genome in the bone marrow.
    DISCUSSION AND EVALUATION: It is described here, a case of fatal dengue with clinical features of HPS. Though BMAT results did not show the presence of macrophage hemophagocytosis, other laboratory features were consistent with HPS especially marked elevation of ferritin, sCD163 and sCD25. Detection of dengue virus in the patient's bone marrow, fifteen days after the onset of fever was also consistent with the suggestion that the HPS is associated with dengue virus infection.
    CONCLUSIONS: The findings highlight HPS as a possible complication leading to severe dengue and revealed persistent dengue virus infection of the bone marrow. Detection of HPS markers; ferritin, sCD163 and sCD25, therefore, should be considered for early recognition of HPS-associated dengue.
    KEYWORDS: Bone marrow; Dengue; Ferritin; Hemophagocytic syndrome; MAS; Macrophage
    Study site: University Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia
  15. Ahmad SN, Zaharim WN, Sulaiman S, Hasan Baseri DF, Mohd Rosli NA, Ang LS, et al.
    ACS Omega, 2020 Dec 29;5(51):33253-33261.
    PMID: 33403287 DOI: 10.1021/acsomega.0c04937
    Density functional theory computational investigation was performed to study the electronic structures, muon sites, and the associated hyperfine interactions in [Au25(SR)18]0 and [Au25(SeR)18]0 where R is phenylethane. The calculated electronic structures show inhomogeneous spin density distribution and are also affected by different ligands. The two most stable muon sites near Au atoms in the thiolated system are MAu11 and MAu6. When the thiolate ligands were replaced by selenolate ligands, the lowest energy positions of muons moved to MAu6 and MAu5. Muons prefer to stop inside the Au12 icosahedral shell, away from the central Au and the staple motifs region. Muonium states at phenyl ring and S/Se atoms in the ligand were found to be stable and the Fermi contact fields are much larger as compared to the field experienced by muons near Au atoms.
  16. Bakhtiar MF, Too CL, Tang MM, Sulaiman S, Tan LK, Ahmad-Fauzi NA, et al.
    Clin Exp Allergy, 2019 04;49(4):537-540.
    PMID: 30693574 DOI: 10.1111/cea.13347
  17. Tan KK, Zulkifle NI, Sulaiman S, Pang SP, NorAmdan N, MatRahim N, et al.
    BMC Evol. Biol., 2018 04 24;18(1):58.
    PMID: 29699483 DOI: 10.1186/s12862-018-1175-4
    BACKGROUND: Dengue virus type 3 genotype III (DENV3/III) is associated with increased number of severe infections when it emerged in the Americas and Asia. We had previously demonstrated that the DENV3/III was introduced into Malaysia in the late 2000s. We investigated the genetic diversity of DENV3/III strains recovered from Malaysia and examined their phylogenetic relationships against other DENV3/III strains isolated globally.

    RESULTS: Phylogenetic analysis revealed at least four distinct DENV3/III lineages. Two of the lineages (DENV3/III-B and DENV3/III-C) are current actively circulating whereas the DENV3/III-A and DENV3/III-D were no longer recovered since the 1980s. Selection pressure analysis revealed strong evidence of positive selection on a number of amino acid sites in PrM, E, NS1, NS2a, NS2b, NS3, NS4a, and NS5. The Malaysian DENV3/III isolates recovered in the 1980s (MY.59538/1987) clustered into DENV3/III-B, which was the lineage with cosmopolitan distribution consisting of strains actively circulating in the Americas, Africa, and Asia. The Malaysian isolates recovered after the 2000s clustered within DENV3/III-C. This DENV3/III-C lineage displayed a more restricted geographical distribution and consisted of isolates recovered from Asia, denoted as the Asian lineage. Amino acid variation sites in NS5 (NS5-553I/M, NS5-629 T, and NS5-820E) differentiated the DENV3/III-C from other DENV3 viruses. The codon 629 of NS5 was identified as a positively selected site. While the NS5-698R was identified as unique to the genome of DENV3/III-C3. Phylogeographic results suggested that the recent Malaysian DENV3/III-C was likely to have been introduced from Singapore in 2008 and became endemic. From Malaysia, the virus subsequently spread into Taiwan and Thailand in the early part of the 2010s and later reintroduced into Singapore in 2013.

    CONCLUSIONS: Distinct clustering of the Malaysian old and new DENV3/III isolates suggests that the currently circulating DENV3/III in Malaysia did not descend directly from the strains recovered during the 1980s. Phylogenetic analyses and common genetic traits in the genome of the strains and those from the neighboring countries suggest that the Malaysian DENV3/III is likely to have been introduced from the neighboring regions. Malaysia, however, serves as one of the sources of the recent regional spread of DENV3/III-C3 within the Asia region.

  18. Azis RS, Che Muda NN, Hassan J, Shaari AH, Ibrahim IR, Mustaffa MS, et al.
    Materials (Basel), 2018 Nov 06;11(11).
    PMID: 30404131 DOI: 10.3390/ma11112190
    This paper investigates the effect of the ratio of ammonium nitrate (AN) on the structural, microstructural, magnetic, and alternating current (AC) conductivity properties of barium hexaferrite (BaFe12O19). The BaFe12O19 were prepared by using the salt melt method. The samples were synthesized using different powder-to-salt weight ratio variations (1:3, 1:4, 1:5, 1:6 and 1:7) of BaCO₃ + Fe₂O₃ and ammonium nitrate salt. The NH₄NO₃ was melted on a hot plate at 170 °C. A mixture of BaCO₃ and Fe₂O₃ were added into the NH₄NO₃ melt solution and stirred for several hours using a magnetic stirrer under a controlled temperature of 170 °C. The heating temperature was then increased up to 260 °C for 24 hr to produce an ash powder. The x-ray diffraction (XRD) results show the intense peak of BaFe12O19 for all the samples and the presence of a small amount of the impurity Fe₂O₃ in the samples, at a ratio of 1:5 and 1:6. From the Fourier transform infra-red (FTIR) spectra, the band appears at 542.71 cm - 1 and 432.48 cm - 1 , which corresponding to metal⁻oxygen bending and the vibration of the octahedral sites of BaFe12O19. The field emission scanning electron microscope (FESEM) images show that the grains of the samples appear to stick each other and agglomerate at different masses throughout the image with the grain size 5.26, 5.88, 6.14, 6.22, and 6.18 µm for the ratios 1:3, 1:4, 1:5, 1:6, and 1:7 respectively. From the vibrating sample magnetometer (VSM) analysis, the magnetic properties of the sample ratio at 1:3 show the highest value of coercivity Hc of 1317 Oe, a saturation magnetization Ms of 91 emu/g, and a remnant Mr of 44 emu/g, respectively. As the temperature rises, the AC conductivity is increases with an increase in frequency.
  19. Sulaiman S, Chowdhury SR, Fauzi MB, Rani RA, Yahaya NHM, Tabata Y, et al.
    Int J Mol Sci, 2020 Apr 13;21(8).
    PMID: 32294921 DOI: 10.3390/ijms21082688
    Recent advancement in cartilage tissue engineering has explored the potential of 3D culture to mimic the in vivo environment of human cartilaginous tissue. Three-dimensional culture using microspheres was described to play a role in driving the differentiation of mesenchymal stem cells to chondrocyte lineage. However, factors such as mechanical agitation on cell chondrogenesis during culture on the microspheres has yet to be elucidated. In this study, we compared the 2D and 3D culture of bone-marrow-derived mesenchymal stem cells (BMSCs) on gelatin microspheres (GMs) in terms of MSC stemness properties, immune-phenotype, multilineage differentiation properties, and proliferation rate. Then, to study the effect of mechanical agitation on chondrogenic differentiation in 3D culture, we cultured BMSCs on GM (BMSCs-GM) in either static or dynamic bioreactor system with two different mediums, i.e., F12: DMEM (1:1) + 10% FBS (FD) and chondrogenic induction medium (CIM). Our results show that BMSCs attached to the GM surface and remained viable in 3D culture. BMSCs-GM proliferated faster and displayed higher stemness properties than BMSCs on a tissue culture plate (BMSCs-TCP). GMs also enhanced the efficiency of in-vitro chondrogenesis of BMSCs, especially in a dynamic culture with higher cell proliferation, RNA expression, and protein expression compared to that in a static culture. To conclude, our results indicate that the 3D culture of BMSCs on gelatin microsphere was superior to 2D culture on a standard tissue culture plate. Furthermore, culturing BMSCs on GM in dynamic culture conditions enhanced their chondrogenic differentiation.
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