Displaying publications 61 - 80 of 152 in total

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  1. Development of magnetic porous coordination polymer adsorbent for the removal and preconcentration of Pb(II) from environmental water samples
    Al'Abri AM, Mohamad S, Abdul Halim SN, Abu Bakar NK
    Environ Sci Pollut Res Int, 2019 Apr;26(11):11410-11426.
    PMID: 30805837 DOI: 10.1007/s11356-019-04467-w
    A novel porous coordination polymer adsorbent (BTCA-P-Cu-CP) based on a piperazine(P) as a ligand and 1,2,4,5-benzenetetracarboxylic acid (BTCA) as a linker was synthesized and magnetized to form magnetic porous coordination polymer (BTCA-P-Cu-MCP). Fourier transform infrared (FTIR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), field emission scanning electron microscope(FESEM), energy-dispersive X-ray spectroscopy(EDS), CHN, and Brunauer-Emmett-Teller(BET) analysis were used to characterize the synthesized adsorbent. BTCA-P-Cu-MCP was used for removal and preconcentration of Pb(II) ions from environmental water samples prior to flame atomic absorption spectrometry(FAAS) analysis. The maximum adsorption capacity of BTCA-P-Cu-MCP was 582 mg g-1. Adsorption isotherm, kinetic, and thermodynamic parameters were investigated for Pb(II) ions adsorption. Magnetic solid phase extraction (MSPE) method was used for preconcentration of Pb(II) ions and the parameters influencing the preconcentration process have been examined. The linearity range of proposed method was 0.1-100 μg L-1 with a preconcentration factor of 100. The limits of detection and limits of quantification for lead were 0.03 μg L-1 and 0.11 μg L-1, respectively. The intra-day (n = 7) and inter-day (n = 3) relative standard deviations (RSDs) were 1.54 and 3.43% respectively. The recoveries from 94.75 ± 4 to 100.93 ± 1.9% were obtained for rapid extraction of trace levels of Pb(II) ions in different water samples. The results showed that the BTCA-P-Cu-MCP was steady and effective adsorbent for the decontamination and preconcentration of lead ions from the aqueous environment.
  2. Thyroid function status evaluation in patient post-radiotherapy for nasopharyngeal carcinoma: A retrospective study
    Loh ZH, Mohamad S, Gan BC, Zakaria Z, Mohamad I
    Med J Malaysia, 2023 Mar;78(2):197-201.
    PMID: 36988530
    INTRODUCTION: Nasopharyngeal carcinoma (NPC) is among the most common malignancy in Malaysia. Radiationinduced hypothyroidism has been reported in other countries. However, in Malaysia, no studies were ever done to determine the effect of radiation on hypothyroidism. The objective of this study is to evaluate the practice of taking thyroid function test (TFT) and determine hypothyroidism post-radiation in patients with NPC.

    MATERIALS AND METHODS: A retrospective study on the symptoms and results of TFT according to the dosage of intensity-modulated radiotherapy (IMRT) given to patients with NPC. Data were traced and analysed.

    RESULTS: A total of 78 patients were identified. All patients received IMRT with 33-35 fractions of radiotherapy (RT) with total dosage of 66-70 Gray given. Not all patients had their thyroid function status measured routinely. Twelve patients did have symptoms of hypothyroidism. TFT were obtained in this group but the results were normal. No correlation was found between RT and hypothyroidism.

    CONCLUSION: There was no correlation between IMRT and the development of hypothyroidism. A prospective study with better control of inclusion and exclusion criteria, and longer follow-up period with TFT, is needed to demonstrate the consistency of these findings.

  3. Ensemble-based molecular docking and spectrofluorometric analysis of interaction between cytotoxin and tumor necrosis factor receptor 1
    Misuan N, Mohamad S, Tubiana T, Yap MKK
    J Biomol Struct Dyn, 2023 Mar 16.
    PMID: 36927291 DOI: 10.1080/07391102.2023.2188945
    Cytotoxin (CTX) is a three-finger toxin presents predominantly in cobra venom. The functional site of the toxin is located at its three hydrophobic loop tips. Its actual mechanism of cytotoxicity remains inconclusive as few conflicting hypotheses have been proposed in addition to direct cytolytic effects. The present work investigated the interaction between CTX and death receptor families via ensemble-based molecular docking and fluorescence titration analysis. Multiple sequence alignments of different CTX isoforms obtained a conserved CTX sequence. The three-dimensional structure of the conserved CTX was later determined using homology modelling, and its quality was validated. Ensemble-based molecular docking of CTX was performed with different death receptors, such as Fas-ligand and tumor necrosis factor receptor families. Our results showed that tumor necrosis factor receptor 1 (TNFR1) was the best receptor interacting with CTX attributed to the interaction of all three functional loops and evinced with low HADDOCK, Z-score and RMSD value. The interaction between CTX and TNFR1 was also supported by a concentration-dependent reduction of fluorescence intensity with increasing binding affinity. The possible intermolecular interactions between CTX and TNFR1 were Van der Waals forces and hydrogen bonding. Our findings suggest a possibility that CTX triggers apoptosis cell death through non-covalent interactions with TNFR1.Communicated by Ramaswamy H. Sarma.
  4. Fulltext Frequency of Mycoplasma pneumoniae, Legionella pneumophila and Chlamydia spp. among patients with atypical pneumonia in Tehran
    Noori Goodarzi N, Pourmand MR, Rajabpour M, Arfaatabar M, Mosadegh M, Syed Mohamad SA
    New Microbes New Infect, 2020 Sep;37:100744.
    PMID: 32953125 DOI: 10.1016/j.nmni.2020.100744
    Mycoplasma pneumoniae, Legionella pneumophila and Chlamydia pneumoniae are the most common bacterial agents, which account for 15-40%, 2-15% and 5-10% of atypical community-acquired pneumonia (CAP) respectively. These agents are mostly associated with infection in the outpatient setting. The aim of this study was to evaluate the frequency of these pathogens among patients with CAP attending outpatient clinics in Tehran. A cross-sectional study was carried out of 150 patients attending to educational hospitals in Tehran with CAP. M. pneumoniae, L. pneumophila and Chlamydia spp. were detected by PCR assay, targeting the P1 adhesion gene, macrophage infectivity potentiator (mip) gene and 16S rRNA gene respectively from throat swabs obtained from each patient. A total of 86 (57.3%) of 150 patients were women; median age was 50 years (interquartile range, 35-65 years). M. pneumoniae, L. pneumophila and Chlamydia spp. were detected in 37 (24.7%), 25 (16.7%) and 11 (7.3%) patients respectively; of these, 66 patients (44%) were infected at least by one of these three pathogens. The frequency of L. pneumophila was significantly higher among patients over 60 years old (p 0.03). Coinfection was detected in seven patients (4.7%); six were infected by M. pneumoniae and L. pneumophila, and only one was infected by L. pneumophila and Chlamydia spp. M. pneumoniae was the most prevalent agent of atypical CAP, and L. pneumophila was more likely to infect elderly rather than younger people. Further studies on the prevalence of CAP and its aetiologic agents are needed to improve the diagnosis and treatment of CAP patients.
  5. Fulltext Tocotrienol supplementation improves late-phase fracture healing compared to alpha-tocopherol in a rat model of postmenopausal osteoporosis: a biomechanical evaluation
    Mohamad S, Shuid AN, Mokhtar SA, Abdullah S, Soelaiman IN
    Evid Based Complement Alternat Med, 2012;2012:372878.
    PMID: 22829855 DOI: 10.1155/2012/372878
    This study investigated the effects of α-tocopherol and palm oil tocotrienol supplementations on bone fracture healing in postmenopausal osteoporosis rats. 32 female Sprague-Dawley rats were divided into four groups. The first group was sham operated (SO), while the others were ovariectomised. After 2 months, the right femora were fractured under anesthesia and fixed with K-wire. The SO and ovariectomised-control rats (OVXC) were given olive oil (vehicle), while both the alpha-tocopherol (ATF) and tocotrienol-enriched fraction (TEF) groups were given alpha-tocopherol and tocotrienol-enriched fraction, respectively, at the dose of 60 mg/kg via oral gavages 6 days per week for 8 weeks. The rats were then euthanized and the femora dissected out for bone biomechanical testing to assess their strength. The callous of the TEF group had significantly higher stress parameter than the SO and OVXC groups. Only the SO group showed significantly higher strain parameter compared to the other treatment groups. The load parameter of the OVXC and ATF groups was significantly lower than the SO group. There was no significant difference in the Young's modulus between the groups. In conclusion, tocotrienol is better than α-tocopherol in improving the biomechanical properties of the fracture callous in postmenopausal osteoporosis rat model.
  6. Efficacy of Oxy-Ionic Solutions With Varying pH Levels Against Streptococcus mutans In Vitro
    Ming X, Hassan R, Mohamad S, Shahidan WNS
    Cureus, 2024 May;16(5):e61025.
    PMID: 38800772 DOI: 10.7759/cureus.61025
    Background Chlorhexidine (CHX) is a widely used antimicrobial agent known for its ability to inhibit cariogenic bacteria, reduce plaque formation, neutralize acidity, and promote remineralization. However, the effectiveness of oxy-ionic solutions at different pH levels as an alternative antimicrobial treatment requires further exploration. This study aims to compare the antimicrobial effects of oxy-ionic solutions at various pH levels with those of CHX and fluoride. Methodology This study employed disc diffusion tests to measure the inhibition zone diameters of each solution and broth dilution assays to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Results The oxy-ionic solutions exhibited varying degrees of antimicrobial effectiveness depending on their pH levels. The solution at pH 5 demonstrated the best antimicrobial performance among the oxy-ionic solutions, with inhibition zones comparable to those of CHX. The MIC and MBC values indicated that oxy-ionic solutions in mildly acidic environments generally resulted in better antimicrobial activity. Conclusions The study concludes that while CHX remains highly effective against cariogenic bacteria, oxy-ionic solutions, particularly at pH 5, offer a promising alternative. The antimicrobial efficacy of oxy-ionic solutions is influenced by their pH levels. Further research is recommended to explore the long-term effects and clinical applications of oxy-ionic solutions in maintaining oral health and preventing disease.
  7. Seroprevalence and sociodemographic characteristics of Toxoplasma gondii infection in patients with psychiatric disorders in Malaysia
    Maisarah A, Mohamad S, Husain M, Abdullah S, Noordin R
    Acta Trop, 2024 May 04;255:107241.
    PMID: 38710263 DOI: 10.1016/j.actatropica.2024.107241
    Toxoplasma gondii is a neurotropic protozoan parasite that affects neuronal processing in the brain. This study aimed to investigate the prevalence of T. gondii infection in psychiatric disorder patients. We also investigated the potential association between sociodemographic, clinical manifestation, and behavior of Toxoplasma-seropositive patients with psychiatric disorders. Commercial ELISAs (IgG, IgM, and IgG avidity) using serum and PCR using buffy coat were performed on samples from 54 individuals in each of the following groups: patients diagnosed with depressive disorder, bipolar disorder, and schizophrenia, as well as psychiatrically healthy subjects (control group). They were recruited from the Hospital Universiti Sains Malaysia in Kelantan, Malaysia. Of 54 patients with depressive disorder, 24/54 (44.4 %) were seropositive for IgG, and four (16.7 %) were IgG+/IgM+. Among the latter, a high avidity index indicating a past infection was observed in half of the samples (50.0 %), and the other half (50.0 %) showed a low avidity index, indicating a possible recent infection. Meanwhile, 30/54 (55.6 %) patients with bipolar disorder were seropositive for IgG+, five (16.7 %) were IgG+/IgM+, and four of them had a high avidity index, and one had a low avidity index. Patients with schizophrenia showed 29/54 (53.7 %) seropositive for IgG, two of them (6.9 %) were IgG+/IgM+; one of latter had a high avidity index, and one had a low avidity index. Of 54 people in the control group, 37.0 % (20/54) were seropositive for T. gondii IgG antibodies. However, no significant difference was observed in seroprevalence between the control group and each patient group. No PCR-positive results were documented. A Chi-Square and multiple logistic regression showed that age (p = 0.031), close contact with cats/pets (p = 0.033) and contact with soil (p = 0.012) were significantly associated with Toxoplasma seropositivity in patients with psychiatric disorders. Additional research is needed to elucidate the causal relationships and underlying mechanisms.
  8. Colorimetric strategies applicable for loop-mediated isothermal amplification
    Saifuddin SA, Rashid R, Nor Azmi NJ, Mohamad S
    J Microbiol Methods, 2024 Aug;223:106981.
    PMID: 38945305 DOI: 10.1016/j.mimet.2024.106981
    In recent years, loop-mediated isothermal amplification (LAMP) has gained popularity for detecting various pathogen-specific genes due to its superior sensitivity and specificity compared to conventional polymerase chain reaction (PCR). The simplicity and flexibility of naked-eye detection of the amplicon make LAMP an ideal rapid and straightforward diagnostic tool, especially in resource-limited laboratories. Colorimetric detection is one of the simplest and most straightforward among all detection methods. This review will explore various colorimetric dyes used in LAMP techniques, examining their reaction mechanisms, advantages, limitations and latest applications.
  9. Fulltext A Comparative Study of Selected Trace Element Content in Malay and Chinese Traditional Herbal Medicine (THM) Using an Inductively Coupled Plasma-Mass Spectrometer (ICP-MS)
    Rasdi FL, Bakar NK, Mohamad S
    Int J Mol Sci, 2013 Feb 01;14(2):3078-93.
    PMID: 23377017 DOI: 10.3390/ijms14023078
    A total of 60 products of traditional herbal medicine (THM) in various dosage forms of herbal preparation were analyzed to determine selected trace elements (i.e., Zn, Mn, Cu, Cd, and Se) using ICP-MS. Thirty types of both Chinese and Malay THMs were chosen to represent each population. The closed vessel acid microwave digestion method, using CEM MARS 5, was employed for the extraction of the selected trace elements. The digestion method applied was validated by using certified reference material from the Trace Element in Spinach Leaves (SRM1570a). The recoveries of all elements were found to be in the range of 85.3%-98.9%. The results indicated that Zn, Mn, Cu, Cd and Se have their own trends of concentrations in all samples studied. The daily intake concentrations of the elements were in the following order: Mn > Zn > Cu > Se > Cd. Concentrations of all five elements were found to be dominant in Chinese THMs. The essentiality of the selected trace elements was also assessed, based on the recommended daily allowance (RDA), adequate intake (AI) and the United States Pharmacopeia (USP) for trace elements as reference. The concentrations of all elements studied were below the RDA, AI and USP values, which fall within the essential concentration range, except for cadmium.
  10. Fulltext Controlling the Emission Spectrum of Binary Emitting Polymer Hybrids by a Systematic Doping Strategy via Förster Resonance Energy Transfer for White Emission
    Al-Asbahi BA, AlSalhi MS, Fatehmulla A, Jumali MHH, Qaid SMH, Mujamammi WM, et al.
    Micromachines (Basel), 2021 Nov 08;12(11).
    PMID: 34832783 DOI: 10.3390/mi12111371
    Tuning the emission spectrum of both binary hybrids of poly (9,9'-di-n-octylfluorenyl-2,7-diyl) (PFO) with each poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) and poly[2-methoxy-5-(3,7-dimethyl-octyloxy)-1,4-phenylenevinylene] end-capped with Dimethyl phenyl (MDMO-PPV-DMP) by a systematic doping strategy was achieved. Both binary hybrid thin films of PFO/MEH-PPV and PFO/MDMO-PPV-DMP with various weight ratios were prepared via solution blending method prior to spin coating onto the glass substrates. The conjugation length of the PFO was tuned upon addition of acceptors (MEH-PPV or MDMO-PPV-DMP), as proved from shifting the emission and absorption peaks of the binary hybrids toward the acceptor in addition to enhancing the acceptor emission and reducing the absorbance of the PFO. Förster resonance energy transfer (FRET) is more efficient in the binary hybrid of PFO/MDMO-PPV-DMP than in the PFO/MEH-PPV. The efficient FRET in both hybrid thin films played the major role for controlling their emission and producing white emission from optimum ratio of both binary hybrids. Moreover, the tuning of the emission color can be attributed to the cascade of energy transfer from PFO to MEH-PPV, and then to MDMO-PPV-DMP.
  11. A laudable strategy to manage bacterial panicle blight disease of rice using biocontrol agents
    Ngalimat MS, Mohd Hata E, Zulperi D, Ismail SI, Ismail MR, Mohd Zainudin NAI, et al.
    J Basic Microbiol, 2023 Nov;63(11):1180-1195.
    PMID: 37348082 DOI: 10.1002/jobm.202300182
    Bacterial panicle blight (BPB) disease is a dreadful disease in rice-producing countries. Burkholderia glumae, a Gram-negative, rod-shaped, and flagellated bacterium was identified as the primary culprit for BPB disease. In 2019, the disease was reported in 18 countries, and to date, it has been spotted in 26 countries. Rice yield has been reduced by up to 75% worldwide due to this disease. Interestingly, the biocontrol strategy offers a promising alternative to manage BPB disease. This review summarizes the management status of BPB disease using biological control agents (BCA). Bacteria from the genera Bacillus, Burkholderia, Enterobacter, Pantoea, Pseudomonas, and Streptomyces have been examined as BCA under in vitro, glasshouse, and field conditions. Besides bacteria, bacteriophages have also been reported to reduce BPB pathogens under in vitro and glasshouse conditions. Here, the overview of the mechanisms of bacteria and bacteriophages in controlling BPB pathogens is addressed. The applications of BCA using various delivery methods could effectively manage BPB disease to benefit the agroecosystems and food security.
  12. Retinal Vessel Analysis as a Novel Screening Tool to Identify Childhood Acute Lymphoblastic Leukemia Survivors at Risk of Cardiovascular Disease
    Azanan MS, Chandrasekaran S, Rosli ES, Chua LL, Oh L, Chin TF, et al.
    J Pediatr Hematol Oncol, 2020 08;42(6):e394-e400.
    PMID: 32118813 DOI: 10.1097/MPH.0000000000001766
    BACKGROUND: Microvascular endothelial dysfunction is central to the pathogenesis of cardiovascular disease (CVD). The eye offers direct access for endothelial health assessment via the retinal microvasculature. The aim of the study was to investigate whether image-based retinal vessel analysis is a feasible method of assessing endothelial health in survivors of childhood acute lymphoblastic leukemia (cALL).

    MATERIALS AND METHODS: Cardiovascular risk factors (CRFs) were estimated using the 30-year Framingham Risk Score in 73 childhood leukemia survivors (median age: 25; median years from diagnosis: 19) and 78 healthy controls (median age: 23). Radial arterial stiffness was measured using pulse wave analyzer, while endothelial activation markers were measured by soluble intercellular adhesion molecule 1 (sICAM-1) and soluble vascular cell adhesion molecule 1 (sVCAM-1). Retinal fundus images were analyzed for central retinal artery/vein equivalents (CRAE/CRVE) and arteriolar-venular ratio (AVR).

    RESULTS: cALL survivors had higher CRF (P<0.0001), arterial stiffness (P=0.001), and sVCAM-1 (P=0.007) compared with controls. Survivors also had significantly higher CRVE (P=0.021) while AVR was significantly lower (P=0.026) in survivors compared with controls, compatible with endothelial dysfunction. In cALL survivors with intermediate risk for CVD, CRAE, and AVR are significantly lower, while sVCAM-1 and sICAM-1 are significantly higher when compared with survivors with low CVD risk after adjusting with covariates (age, sex, and smoking status).

    CONCLUSIONS: cALL survivors have an increased risk of CVD compared with age-matched peers. The survivors demonstrated microvasculopathy, as measured by retinal vascular analysis, in addition to physical and biochemical evidence of endothelial dysfunction. These changes predate other measures of CVD. Retinal vessel analysis may be utilized as a robust screening tool for identifying survivors at increased risk for developing CVD.

  13. H274Y's Effect on Oseltamivir Resistance: What Happens Before the Drug Enters the Binding Site
    Yusuf M, Mohamed N, Mohamad S, Janezic D, Damodaran KV, Wahab HA
    J Chem Inf Model, 2016 Jan 25;56(1):82-100.
    PMID: 26703840 DOI: 10.1021/acs.jcim.5b00331
    Increased reports of oseltamivir (OTV)-resistant strains of the influenza virus, such as the H274Y mutation on its neuraminidase (NA), have created some cause for concern. Many studies have been conducted in the attempt to uncover the mechanism of OTV resistance in H274Y NA. However, most of the reported studies on H274Y focused only on the drug-bound system, so the direct effects of the mutation on NA itself prior to drug binding still remain unclear. Therefore, molecular dynamics simulations of NA in apo form, followed by principal component analysis and interaction energy calculations, were performed to investigate the structural changes of the NA binding site as a result of the H274Y mutation. It was observed that the disruption of the NA binding site due to the H274Y mutation was initiated by the repulsive effect of Y274 on the 250-loop, which in turn altered the hydrogen-bonding network around residue 274. The rotated W295 side chain caused the upward movement of the 340-loop. Consequently, sliding box docking results suggested that the binding pathway of OTV was compromised because of the disruption of this binding site. This study also highlighted the importance of the functional group at C6 of the sialic acid mimicry. It is hoped that these results will improve the understanding of OTV resistance and shed some light on the design of a novel anti-influenza drug.
  14. Fulltext Antiretroviral drug resistance and HIV-1 subtypes among treatment-naive prisoners in Kelantan, Malaysia
    Ariffin TA, Mohamad S, Yusuf WN, Shueb RH
    J Infect Dev Ctries, 2014 Aug;8(8):1063-7.
    PMID: 25116676 DOI: 10.3855/jidc.4095
    INTRODUCTION: The widespread use of highly active antiretroviral therapy (HAART) and continuous reports of HIV-1 strains developing resistance to these drugs is rather alarming, as transmission of resistant viruses to newly infected persons is possible. This study aimed to determine HIV-1 subtypes and the prevalence of primary mutations associated with antiretroviral (ARV) resistance among treatment-naive prisoners on the east coast of Malaysia.
    METHODOLOGY: Viral RNA was extracted from plasma samples of 21 treatment-naive prisoners. Protease (PR) and reverse transcriptase (RT) regions were amplified and sequenced. Stanford HIV database algorithms were used for interpretation of resistance, and phylogenetic analysis was performed for subtype assignment.
    RESULTS: In the PR gene, no antiviral resistance-associated mutation was detected. For RT-associated mutations, K103N was the most prevalent in sequenced samples (14.3%). Genetic subtyping on the pol gene revealed that the majority of the prisoners were infected with subtype CRF33_01B (52.4%).
    CONCLUSION: Continuous surveillance of newly infected individuals is required to help strategize the best antiviral treatment for these patients.
  15. Kinetic asymmetries during running in male youth
    Rumpf MC, Cronin JB, Mohamad IN, Mohamad S, Oliver JL, Hughes MG
    Phys Ther Sport, 2014 Feb;15(1):53-7.
    PMID: 23850007 DOI: 10.1016/j.ptsp.2013.03.001
    A possible injury risk factor is limb asymmetry, which may differ across maturation given the adult growth spurt. The aim of this study is to quantify the magnitude of asymmetry in a number of kinetic variables during a running task in male youth of different maturity status.
  16. Malaysianol B, an oligostilbenoid derivative from Dryobalanops lanceolata
    Wibowo A, Ahmat N, Hamzah AS, Low AL, Mohamad SA, Khong HY, et al.
    Fitoterapia, 2012 Dec;83(8):1569-75.
    PMID: 22982329 DOI: 10.1016/j.fitote.2012.09.004
    A new oligostilbenoid tetramer, malaysianol B (1), was isolated from the acetone extract of the stem bark of Dryobalanops lanceolata along with seven oligostilbenoids tetramers; hopeaphenol (2), stenophyllol A (3), nepalensinol B (4), vaticanol B (5) and C (6), upunaphenol D (7), and flexuosol A (8). The structures of the isolated compounds were established on the basis of their spectroscopic data evidence. The antibacterial activity of the isolated compounds was evaluated using resazurin microtitre-plate assay.
  17. Fulltext Assessing subtypes and drug resistance mutations among HIV-1 infected children who failed antiretroviral therapy in Kelantan, Malaysia
    Mohamad S, Deris ZZ, Yusoff NK, Ariffin TA, Shueb RH
    Braz J Infect Dis, 2012 May-Jun;16(3):284-8.
    PMID: 22729198
    Antiretroviral (ARV) therapy has dramatically reduced morbidity and mortality in human immunodeficiency virus 1 (HIV-1) infected children. However, development of ARV resistance in these children is a major public health problem due to lack of availability of and access to new drugs. This study was conducted in order to identify circulating HIV subtypes and recombinant forms and evaluate the drug resistance mutation patterns in 18 HIV-1 infected children failing ARV treatment in Kelantan, Malaysia. Genotyping for codon 1-99 of protease (PR) and 1-250 of reverse transcriptase (RT) were performed by polymerase chain reaction (PCR) amplification and DNA sequencing. Subsequently, these were phylogenetically analyzed to determine the subtypes. CRF33_01B (44.4%) was found to be the predominant HIV subtype, followed by B (27.8%), CRF15_01B (16.7%) and CRF01_AE (11.1%) subtypes. The most prevalent RT mutations were T215F/V/Y (66.7%), D67G/N (55.6%), K219Q/E/R (44.4%), M184V/I (38.9%), K70R/E (27.8%) and M41L (27.8%), associated with nucleoside reverse transcriptase inhibitors (NRTI) resistance; and K103N (55.6%), G190A (33.3%), and K101P/E/H (27.8%) associated with non-nucleoside reverse transcriptase inhibitors (NNRTI) resistance. The results showed a possible emergence of CRF33_01B as current predominant subtypes/circulating recombinant forms (CRFs), and a high frequency of primary mutations among HIV-1 infected children after failure of ARV therapy in Kelantan, Malaysia.
  18. Construction and characterization of a Burkholderia pseudomallei wzm deletion mutant
    Yuen CW, Ong EB, Mohamad S, Manaf UA, Najimudin N
    J Microbiol Biotechnol, 2012 Oct;22(10):1336-42.
    PMID: 23075783
    In Burkholderia pseudomallei, the pathogen that causes melioidosis, the gene cluster encoding the capsular polysaccharide, is located on chromosome 1. Among the 19 capsular genes in this cluster, wzm has not been thoroughly studied. To study the function of wzm, we generated a deletion mutant and compared it with the wild-type strain. The mutant produced less biofilm in minimal media and was more sensitive to desiccation and oxidative stress compared with the wild-type strain, indicating that wzm is involved in biofilm formation and membrane integrity. Scanning electron microscopy showed that the bacterial cells of the mutant strain have more defined surfaces with indentations, whereas cells of the wild-type strain do not.
  19. Fulltext The Chemical Components of Sesbania grandiflora Root and Their Antituberculosis Activity
    Hasan N, Osman H, Mohamad S, Chong WK, Awang K, Zahariluddin AS
    Pharmaceuticals (Basel), 2012;5(8):882-9.
    PMID: 24280680 DOI: 10.3390/ph5080882
    Three isoflavanoids, isovestitol (1), medicarpin (2), and sativan (3), along with another known compound, betulinic acid (4), were isolated from the root of Sesbania grandiflora. The structures of the isolated compounds were characterised by means of spectroscopic techniques (UV, IR, MS, 1H- and 13C-NMR, DEPT, COSY, HMQC, HMBC, and MS analysis). All the tested compounds 1-4 exhibited antituberculosis activity against Mycobacterium tuberculosis H37Rv, with MIC values of 50 µg/mL for compounds 1-3, and 100 µg/mL for compound 4, whereas, the methanol extract exhibited antituberculosis activity of 625 µg/mL. This is the first report on the occurrence of isoflavonoids in this plant and their antituberculosis activity.
  20. Fulltext Conventional study on novel dicationic ionic liquid inclusion with β-cyclodextrin
    Mohamad S, Surikumaran H, Raoov M, Marimuthu T, Chandrasekaram K, Subramaniam P
    Int J Mol Sci, 2011;12(9):6329-45.
    PMID: 22016662 DOI: 10.3390/ijms12096329
    This study focuses on the synthesis and characterization of the inclusion complex of β-Cyclodextrin (β-CD) with dicationic ionic liquid, 3,3'-(1,4-Phenylenebis [methylene]) bis(1-methyl-1H-imidazol-3-ium) di(bromide) (PhenmimBr). The inclusion complex was prepared at room temperature utilizing conventional kneading technique. Proton ((1)H) NMR and 2D ((1)H-(1)H) COSY NMR were the primary characterization tools employed to verify the formation of the inclusion complex. COSY spectra showed strong correlations between protons of imidazolium and protons of β-CD which indicates that the imidazolium ring of PhenmimBr has entered the cavity of β-CD. UV absorption indicated that β-CD reacts with PhenmimBr to form a 2:1 β-CD-PhenmimBr complex with an apparent formation constant of 2.61 × 10(5) mol&(-2) L(2). Other characterization studies such as UV, FT-IR, XRD, TGA, DSC and SEM studies were also used to further support the formation of the β-CD-PhenmimBr inclusion complex.
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