Displaying publications 81 - 100 of 171 in total

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  1. Othman R, Kiat TS, Khalid N, Yusof R, Newhouse EI, Newhouse JS, et al.
    J Chem Inf Model, 2008 Aug;48(8):1582-91.
    PMID: 18656912 DOI: 10.1021/ci700388k
    A group of flavanones and their chalcones, isolated from Boesenbergia rotunda L., were previously reported to show varying degrees of noncompetitive inhibitory activities toward Dengue virus type 2 (Den2) protease. Results obtained from automated docking studies are in agreement with experimental data in which the ligands were shown to bind to sites other than the active site of the protease. The calculated K(i) values are very small, indicating that the ligands bind quite well to the allosteric binding site. Greater inhibition by pinostrobin, compared to the other compounds, can be explained by H-bonding interaction with the backbone carbonyl of Lys74, which is bonded to Asp75 (one of the catalytic triad residues). In addition, structure-activity relationship analysis yields structural information that may be useful for designing more effective therapeutic drugs against dengue virus infections.
  2. Rahman RA, Ramli R, Rahman NA, Hussaini HM, Idrus SM, Hamid AL
    Int J Pediatr Otorhinolaryngol, 2007 Jun;71(6):929-36.
    PMID: 17442408
    Maxillofacial trauma in children is not common worldwide. Domestic injuries are frequently seen in younger children while older children are mostly involved in motor vehicle accidents (MVA). The objective of this study was to analyze the pattern of maxillofacial injuries in pediatric patients referred to three government main hospitals in different areas of West Malaysia.
  3. Mansor S, Yehye WA, Ariffin A, Rahman NA, Ng SW
    PMID: 21201758 DOI: 10.1107/S1600536808026056
    Two mol-ecules of the title compound, C(21)H(27)NO(3)S, are disposed about a center of inversion, generating an O-H⋯O hydrogen-bonded dimer.
  4. Hussaini HM, Rahman NA, Rahman RA, Nor GM, Ai Idrus SM, Ramli R
    Int J Oral Maxillofac Surg, 2007 Sep;36(9):797-801.
    PMID: 17630250
    Soft-tissue injuries with or without facial bone involvement are the most common presentation following maxillofacial trauma. The objective of this study was to look at the distribution, pattern and type of soft-tissue injury in relation to aetiology. Records of patients over a period of 5 years (1998-2002), who sustained maxillofacial injuries and were treated at Kajang Hospital, a secondary referral hospital, were reviewed. Out of 313 patients with maxillofacial injuries, 295 patients sustained soft-tissue injuries. Males (79%) between 21 and 30 years old (34%) were the majority of patients. Road-traffic accident was the main cause of soft-tissue injuries (75%) with motorcycle accident being the most frequent (40%). The upper lips (23%) and the lower lips (18%) were the most common extraoral site involved, while the labial mucosa and sulcular areas, both accounting for 21%, were the most common intraoral sites. Stringent road-traffic regulations should be practiced in developing countries, as morbidity arising from road-traffic accidents poses a national economic and social problem.
  5. Mansor S, Yehye WA, Ariffin A, Rahman NA, Ng SW
    PMID: 21201778 DOI: 10.1107/S1600536808026202
    The asymmetric unit of the title compound, C(8)H(20)N(+)·C(21)H(26)NO(3)S(-), contains two indpendent ion pairs which are disposed about a psuedo-inversion center, generating an ammonium-carboxylate N-H⋯O hydrogen-bonded four-component cluster. In the crystal structure, adjacent clusters are linked by hydr-oxy-carboxylate O-H⋯O hydrogen bonds, forming a chain.
  6. Rahman RA, Hussaini HM, Rahman NA, Rahman SR, Nor GM, Ai Idrus SM, et al.
    Eur J Trauma Emerg Surg, 2007 Feb;33(1):90-5.
    PMID: 26815981 DOI: 10.1007/s00068-007-5154-5
    The objective of this study was to determine the demographic data as well as other relevant data pertaining to the management of patients with maxillofacial injury in a Malaysian government regional hospital.
  7. Omar NY, Mon TC, Rahman NA, Abas MR
    Sci Total Environ, 2006 Oct 1;369(1-3):76-81.
    PMID: 16766020
    The concentrations and distributions of particle bound polycyclic aromatic hydrocarbons (PAHs) collected over a 10 month period in ambient environment, at street levels as well as during a hazy episode are reported. Ambient and street level distributions of PAHs were similar and their occurrence was attributed to vehicular emissions. However, in haze particles, a different pattern of PAHs was observed, characterized by relatively low levels of benzo[a]pyrene (BaP) and high levels of benzofluoranthenes (BFs). The BaP equivalency results showed that the potential health risk associated with haze smoke particles was 4 times higher than that of street level particles whereas the lowest health risk was associated with ambient atmospheric particles.
  8. Rothan HA, Han HC, Ramasamy TS, Othman S, Rahman NA, Yusof R
    BMC Infect Dis, 2012;12:314.
    PMID: 23171075 DOI: 10.1186/1471-2334-12-314
    Global resurgence of dengue virus infections in many of the tropical and subtropical countries is a major concern. Therefore, there is an urgent need for the development of successful drugs that are both economical and offer a long-lasting protection. The viral NS2B-NS3 serine protease (NS2B-NS3pro) is a promising target for the development of drug-like inhibitors, which are not available at the moment. In this study, we report retrocyclin-1 (RC-1) production in E. coli as a recombinant peptide to test against dengue NS2B-NS3pro.
  9. Heh CH, Othman R, Buckle MJ, Sharifuddin Y, Yusof R, Rahman NA
    Chem Biol Drug Des, 2013 Jul;82(1):1-11.
    PMID: 23421589 DOI: 10.1111/cbdd.12122
    Various works have been carried out in developing therapeutics against dengue. However, to date, no effective vaccine or anti-dengue agent has yet been discovered. The development of protease inhibitors is considered as a promising option, but most previous works have involved competitive inhibition. In this study, we focused on rational discovery of potential anti-dengue agents based on non-competitive inhibition of DEN-2 NS2B/NS3 protease. A homology model of the DEN-2 NS2B/NS3 protease (using West Nile Virus NS2B/NS3 protease complex, 2FP7, as the template) was used as the target, and pinostrobin, a flavanone, was used as the standard ligand. Virtual screening was performed involving a total of 13 341 small compounds, with the backbone structures of chalcone, flavanone, and flavone, available in the ZINC database. Ranking of the resulting compounds yielded compounds with higher binding affinities compared with the standard ligand. Inhibition assay of the selected top-ranking compounds against DEN-2 NS2B/NS3 proteolytic activity resulted in significantly better inhibition compared with the standard and correlated well with in silico results. In conclusion, via this rational discovery technique, better inhibitors were identified. This method can be used in further work to discover lead compounds for anti-dengue agents.
  10. Kong CY, Lai LL, Khoo AYY, Rahman NA, Chin KF
    BMC Surg, 2016 Feb 11;16:8.
    PMID: 26864939 DOI: 10.1186/s12893-016-0123-8
    BACKGROUND: Polypropylene meshes are widely used in hernia repairs. Hernia meshes have been developed incorporating coatings of active agents. One commercially available mesh has a fish oil coating which is promoted as having anti-inflammatory properties. We report a case, a symptomatic foreign body granuloma reaction associated with a fish oil coated polypropylene mesh, which required eventual mesh explantation.

    CASE PRESENTATION: A 61-year old lady with previous peptic ulcer disease underwent a laparoscopic intraperitoneal placement of mesh for incisional hernia utilising a fish oil coated polypropylene mesh. The patient presented 3 months after the procedure complaining of dyspepsia and pain at the operative site. There was no discharge. The patient was managed conservatively. She presented 10 months post-operatively with progressively worsening symptoms and a hard palpable mass in the epigastrium. Abdominal laparoscopy revealed dense adhesive disease around the mesh with exudates. Adhesiolysis, mesh explantation and a partial gastrectomy was performed. Histopathological examination revealed a foreign body granuloma formation to the mesh.

    CONCLUSION: In-vivo studies looking at intraperitoneal mesh placement with fish oil coatings including data on surgical outcomes such as fistula and adhesive characteristics are scarce in the literature. Further monitoring and studies are required to investigate the safety and efficacy profile of this mesh type in in-vivo models.

  11. Yehye WA, Rahman NA, Ariffin A, Abd Hamid SB, Alhadi AA, Kadir FA, et al.
    Eur J Med Chem, 2015 Aug 28;101:295-312.
    PMID: 26150290 DOI: 10.1016/j.ejmech.2015.06.026
    Hindered phenols find a wide variety of applications across many different industry sectors. Butylated hydroxytoluene (BHT) is a most commonly used antioxidant recognized as safe for use in foods containing fats, pharmaceuticals, petroleum products, rubber and oil industries. In the past two decades, there has been growing interest in finding novel antioxidants to meet the requirements of these industries. To accelerate the antioxidant discovery process, researchers have designed and synthesized a series of BHT derivatives targeting to improve its antioxidant properties to be having a wide range of antioxidant activities markedly enhanced radical scavenging ability and other physical properties. Accordingly, some structure-activity relationships and rational design strategies for antioxidants based on BHT structure have been suggested and applied in practice. We have identified 14 very sensitive parameters, which may play a major role on the antioxidant performance of BHT. In this review, we attempt to summarize the current knowledge on this topic, which is of significance in selecting and designing novel antioxidants using a well-known antioxidant BHT as a building-block molecule. Our strategy involved investigation on understanding the chemistry behind the antioxidant activities of BHT, whether through hydrogen or electron transfer mechanism to enable promising anti-oxidant candidates to be synthesized.
  12. Rothan HA, Bahrani H, Mohamed Z, Teoh TC, Shankar EM, Rahman NA, et al.
    PLoS One, 2015;10(5):e0126360.
    PMID: 25970853 DOI: 10.1371/journal.pone.0126360
    Lack of vaccine and effective antiviral drugs against chikungunya virus (CHIKV) outbreaks have led to significant impact on health care in the developing world. Here, we evaluated the antiviral effects of tetracycline (TETRA) derivatives and other common antiviral agents against CHIKV. Our results showed that within the TETRA derivatives group, Doxycycline (DOXY) exhibited the highest inhibitory effect against CHIKV replication in Vero cells. On the other hand, in the antiviral group Ribavirin (RIBA) showed higher inhibitory effects against CHIKV replication compared to Aciclovir (ACIC). Interestingly, RIBA inhibitory effects were also higher than all but DOXY within the TETRA derivatives group. Docking studies of DOXY to viral cysteine protease and E2 envelope protein showed non-competitive interaction with docking energy of -6.6±0.1 and -6.4±0.1 kcal/mol respectively. The 50% effective concentration (EC50) of DOXY and RIBA was determined to be 10.95±2.12 μM and 15.51±1.62 μM respectively, while DOXY+RIBA (1:1 combination) showed an EC50 of 4.52±1.42 μM. When compared, DOXY showed higher inhibition of viral infectivity and entry than RIBA. In contrast however, RIBA showed higher inhibition against viral replication in target cells compared to DOXY. Assays using mice as animal models revealed that DOXY+RIBA effectively inhibited CHIKV replication and attenuated its infectivity in vivo. Further experimental and clinical studies are warranted to investigate their potential application for clinical intervention of CHIKV disease.
  13. Kaka U, Rahman NA, Abubakar AA, Goh YM, Fakurazi S, Omar MA, et al.
    J Pain Res, 2018;11:743-752.
    PMID: 29695926 DOI: 10.2147/JPR.S152475
    Objectives: The effects of pre-emptive infusion of ketamine-lidocaine with tramadol on the suppression of central sensitization were investigated in a dog ovariohysterectomy model.

    Patients and methods: Twelve dogs were randomly assigned to two groups: ketamine-lidocaine-tramadol (KLT) and tramadol (T) groups. Both groups received intravenous tramadol 4 mg/kg body weight as premedication. Immediately after induction, the KLT group received ketamine and lidocaine at 0.5 and 2 mg/kg loading dose, followed by continuous rate infusion of 50 and 100 µg/kg/min, respectively, for 2 hours. Dogs in T group received saline bolus and continuous rate infusion at equi-volume. Intraoperatively, hemodynamic responses to surgical stimulation were recorded, whereas postoperative pain was evaluated using an algometer and short form of the Glasgow composite measure pain scale.

    Results: Intraoperatively, hemodynamic responses to surgical stimulation were obtunded to a greater degree in KLT compared to T group. Postoperatively, the pain scores increased only for the first hour in KLT group, compared to 12 hours in T group. Mechanical thresholds at the abdomen decreased postoperatively between 12 and 60 hours in KLT group versus the entire 72 hours in T group. Thresholds at tibia and radius in both groups increased in the immediate 1 hour postoperatively, but decreased thereafter. Significant decrement of thresholds from baseline were detected in the tibia at 24, 42, and 60 hours in KLT group compared to 24-72 hours in T group, and in the radius between 36 and 48 hours in T group, but none in KLT group.

    Conclusion: Addition of pre-emptive ketamine-lidocaine infusion to single intravenous dose of tramadol enhanced attenuation of central sensitization and improved intra- and postoperative analgesia.

  14. James JG, Izam AS, Nabil S, Rahman NA, Ramli R
    J Craniofac Surg, 2019 8 27;31(1):e22-e26.
    PMID: 31449209 DOI: 10.1097/SCS.0000000000005812
    AIM: The objective of this review was to determine the different types of surgical intervention in the management of nasal bone fractures, the outcomes, and complications associated with each intervention.

    METHODS: A search was conducted using the PubMed and Cochrane Database of Systematic Review databases from January 1, 1997 until September 9, 2017. The search strategy was constructed using the Population Intervention Comparison Outcome framework with keywords related to nasal fracture and its treatment. Two sets of independent researchers performed the analysis. Qualitative analysis was performed using the Methodological Index for Non-Randomized Studies and National Institute for Clinical Excellence methodology for randomized controlled trial checklists.

    RESULTS: The 4276 titles were obtained from PubMed database alone. Exclusion was made based on the title, abstract and full-text analysis. Finally, 23 papers were included and analyzed. Of the 23 papers, 13 (56.5%) were retrospective record review, 2 (8.7%) were randomized clinical trial or a randomized study and 8 case series (34.8%). 16 (69.6%) studies addressed closed reduction, 3 studies (13%) on open reduction and 4 studies (17.4%) addressed both open and closed reduction. The main focus in the outcome in all studies was accuracy of the anatomical reduction of the nasal bones. Three studies (13.0%) reported restoration of function such as breathing comfort or release in respiratory obstruction and another 3 (13.0%) addressed both cosmetic and breathing outcomes. Residual deformity was the most described complications in the studies (30.4%). In general, most of the studies were not of high quality as they lacked in some key elements in the Methodological Index for Non-Randomized Studies checklist.

    CONCLUSION: Both closed and open reduction provided good outcomes in cosmetic and breathing. Septoplasty is recommended to be performed simultaneously with fracture reduction.

  15. Abduraman MA, Hariono M, Yusof R, Rahman NA, Wahab HA, Tan ML
    Heliyon, 2018 Dec;4(12):e01023.
    PMID: 30560214 DOI: 10.1016/j.heliyon.2018.e01023
    Background: Dengue infection is an endemic infectious disease and it can lead to dengue fever, dengue hemorrhagic fever, and/or dengue shock syndromes. Dengue NS2B/NS3 protease complex is essential for viral replication and is a primary target for anti-dengue drug development. In this study, a NS2B/NS3 protease inhibition assay was developed using AlphaScreen® beads and was used to screen compounds for their protease inhibition activities.

    Methods: The assay system utilized a known NS2B/NS3 peptide substrate, a recombinant of NS2B/NS3 protease with proprietary StrepTactin® donor and nickel chelate acceptor beads in 384-well format.

    Results: The optimized assay to screen for NS2B/NS3 protease inhibitors was demonstrated to be potentially useful with reasonable z' factor, coefficient variance and signal to background ratio. However, screening of synthesized thioguanine derivatives using the optimized AlphaScreen® assay revealed weak NS2B/NS3 inhibition activities.

    Conclusion: The AlphaScreen® assay to screen for NS2B/NS3 protease inhibitors is potentially applicable for high throughput screening.

  16. Isa DM, Chin SP, Chong WL, Zain SM, Rahman NA, Lee VS
    J Biol Phys, 2019 03;45(1):63-76.
    PMID: 30680580 DOI: 10.1007/s10867-018-9515-6
    In this study, we investigate the binding interactions of two synthetic antiviral peptides (DET2 and DET4) on type II dengue virus (DENV2) envelope protein domain III. These two antiviral peptides are designed based on the domain III of the DENV2 envelope protein, which has shown significant inhibition activity in previous studies and can be potentially modified further to be active against all dengue strains. Molecular docking was performed using AutoDock Vina and the best-ranked peptide-domain III complex was further explored using molecular dynamics simulations. Molecular mechanics-Poisson-Boltzmann surface area (MM-PBSA) was used to calculate the relative binding free energies and to locate the key residues of peptide-protein interactions. The predicted binding affinity correlated well with the previous experimental studies. DET4 outperformed DET2 and is oriented within the binding site through favorable vdW and electrostatic interactions. Pairwise residue decomposition analysis has revealed several key residues that contribute to the binding of these peptides. Residues in DET2 interact relatively lesser with the domain III compared to DET4. Dynamic cross-correlation analysis showed that both the DET2 and DET4 trigger different dynamic patterns on the domain III. Correlated motions were seen between the residue pairs of DET4 and the binding site while binding of DET2 results in anti-correlated motion on the binding site. This work showcases the use of computational study in elucidating and explaining the experiment observation on an atomic level.
  17. Alahnomi RA, Zakaria Z, Yussof ZM, Althuwayb AA, Alhegazi A, Alsariera H, et al.
    Sensors (Basel), 2021 Mar 24;21(7).
    PMID: 33804904 DOI: 10.3390/s21072267
    Recent developments in the field of microwave planar sensors have led to a renewed interest in industrial, chemical, biological and medical applications that are capable of performing real-time and non-invasive measurement of material properties. Among the plausible advantages of microwave planar sensors is that they have a compact size, a low cost and the ease of fabrication and integration compared to prevailing sensors. However, some of their main drawbacks can be considered that restrict their usage and limit the range of applications such as their sensitivity and selectivity. The development of high-sensitivity microwave planar sensors is required for highly accurate complex permittivity measurements to monitor the small variations among different material samples. Therefore, the purpose of this paper is to review recent research on the development of microwave planar sensors and further challenges of their sensitivity and selectivity. Furthermore, the techniques of the complex permittivity extraction (real and imaginary parts) are discussed based on the different approaches of mathematical models. The outcomes of this review may facilitate improvements of and an alternative solution for the enhancement of microwave planar sensors' normalized sensitivity for material characterization, especially in biochemical and beverage industry applications.
  18. Hiong LC, Voon KL, Abdullah NA, Sattar MA, Rahman NA, Khan AH, et al.
    Acta Pharmacol Sin, 2008 Apr;29(4):451-7.
    PMID: 18358091 DOI: 10.1111/j.1745-7254.2008.00772.x
    The aim of the present study was to investigate the effectiveness of transforming growth factor (TGF)-beta1 antisense oligodeoxynucleotides (ODN) in ameliorating deteriorated kidney function in rats with puromycin-induced chronic renal failure (CRF).
  19. Rahman NA, Katayama T, Wahid MEA, Kasan NA, Khatoon H, Yamada Y, et al.
    Front Bioeng Biotechnol, 2020;8:581628.
    PMID: 33330417 DOI: 10.3389/fbioe.2020.581628
    Antioxidants found in microalgae play an essential role in both animals and humans, against various diseases and aging processes by protecting cells from oxidative damage. In this study, 26 indigenous tropical marine microalgae were screened. Out of the 26 screened strains, 10 were selected and were further investigated for their natural antioxidant compounds which include carotenoids, phenolics, and fatty acids collected in their exponential and stationary phases. The antioxidant capacity was also evaluated by a total of four assays, which include ABTS, DPPH, superoxide radical (O2•-) scavenging capacity, and nitric oxide (•NO-) scavenging capacity. This study revealed that the antioxidant capacity of the microalgae varied between divisions, strains, and growth phase and was also related to the content of antioxidant compounds present in the cells. Carotenoids and phenolics were found to be the major contributors to the antioxidant capacity, followed by polyunsaturated fatty acids linoleic acid (LA), eicosapentaenoic acid (EPA), arachidonic acid (ARA), and docosahexaenoic acid (DHA) compared to other fatty acids. The antioxidant capacity of the selected bacillariophytes and haptophytes was found to be positively correlated to phenolic (R2-value = 0.623, 0.714, and 0.786 with ABTS, DPPH, and •NO-) under exponential phase, and to carotenoid fucoxanthin and β-carotene (R2 value = 0.530, 0.581 with ABTS, and 0.710, 0.795 with O2•-) under stationary phase. Meanwhile, antioxidant capacity of chlorophyte strains was positively correlated with lutein, β-carotene and zeaxanthin under the exponential phase (R2 value = 0.615, 0.615, 0.507 with ABTS, and R2 value = 0.794, 0.659, and 0.509 with •NO-). In the stationary phase, chlorophyte strains were positively correlated with violaxanthin (0.755 with •NO-), neoxanthin (0.623 with DPPH, 0.610 with •NO-), and lutein (0.582 with •NO-). This study showed that antioxidant capacity and related antioxidant compound production of tropical microalgae strains are growth phase-dependent. The results can be used to improve the microalgal antioxidant compound production for application in pharmaceutical, nutraceutical, food, and feed industry.
  20. Roslan MAM, Zulkifli NN, Sobri ZM, Zuan ATK, Cheak SC, Abdul Rahman NA
    PLoS One, 2020;15(7):e0232860.
    PMID: 32645001 DOI: 10.1371/journal.pone.0232860
    Limited information is available that seed biopriming with plant growth-promoting Enterobacter spp. play a prominent role to enhance vegetative growth of plants. Contrary to Enterobacter cloacae, Enterobacter hormaechei is a less-studied counterpart despite its vast potential in plant growth-promotion mainly through the inorganic phosphorus (P) and potassium (K) solubilization abilities. To this end, 18 locally isolated bacterial pure cultures were screened and three strains showed high P- and K-solubilizing capabilities. Light microscopy, biochemical tests and 16S rRNA gene sequencing revealed that strains 15a1 and 40a were closely related to Enterobacter hormaechei while strain 38 was closely related to Enterobacter cloacae (Accession number: MN294583; MN294585; MN294584). All Enterobacter spp. shared common plant growth-promoting traits, namely nitrogen (N2) fixation, indole-3-acetic acid production and siderophore production. The strains 38 and 40a were able to produce gibberellic acid, while only strain 38 was able to secrete exopolysaccharide on agar. Under in vitro germination assay of okra (Abelmoschus esculentus) seeds, Enterobacter spp. significantly improved overall germination parameters and vigor index (19.6%) of seedlings. The efficacy of root colonization of Enterobacter spp. on the pre-treated seedling root tips was confirmed using Scanning Electron Microscopy (SEM). The pot experiment of bioprimed seeds of okra seedling showed significant improvement of the plant growth (> 28%) which corresponded to the increase of P and K uptakes (> 89%) as compared to the uninoculated control plants. The leaf surface area and the SPAD chlorophyll index of bioprimed plants were increased by up to 29% and 9% respectively. This report revealed that the under-explored species of P- and K-solubilizing Enterobacter hormaechei sp. with multiple plant beneficial traits presents a great potential sustainable approach for enhancement of soil fertility and P and K uptakes of plants.
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