Displaying publications 1 - 20 of 34 in total

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  1. Resistance of Pseudomonas pseudomallei to normal human serum bactericidal action
    Ismail G, Razak N, Mohamed R, Embi N, Omar O
    Microbiol. Immunol., 1988;32(7):645-52.
    PMID: 3193910
    The effect of human normal serum (HNS) on Pseudomonas pseudomallei was determined. It is apparent from our data that the organism is resistant to the normal serum bactericidal mechanism. Ancillary experiments to confirm this serum-resistant property of P. pseudomallei were done by examining the effects of growth phase conditions of the bacteria (i.e., logarithmic and stationary phases) and different buffered systems used as diluent in our bactericidal assay. Results obtained showed similar degree of resistance to serum bactericidal killing by 5 strains of the organisms tested. The possible survival advantage of serum-resistance property to P. pseudomallei as bacterial pathogens known to invade the blood stream is discussed.
  2. Inhibition of macromolecular synthesis in cultured macrophages by Pseudomonas pseudomallei exotoxin
    Mohamed R, Nathan S, Embi N, Razak N, Ismail G
    Microbiol. Immunol., 1989;33(10):811-20.
    PMID: 2615673
    Pseudomonas pseudomallei exotoxin was found to be a potent inhibitor of protein and DNA synthesis in cultured macrophages. Inhibition of DNA synthesis occurred at toxin concentrations as low as 1-2 micrograms/ml and inhibition of 3H-thymidine uptake was almost complete at concentrations of 8 micrograms/ml or more. A close correlation between cell damage and inhibition by DNA synthesis was observed. For protein synthesis, inhibition was obtained at much lower doses (0.06-2.0 micrograms/ml) of the toxin. At similar toxin concentrations, DNA synthesis was marginally affected. Further, it was shown that protein synthesis inhibition occurred almost immediately after incubation, reaching its maximal inhibitory effect of 70% after 6 hr. DNA synthesis, however, was minimally affected by a similar toxin concentration even after 10 hr of incubation. The inhibition of macromolecular synthesis in macrophages by P. pseudomallei exotoxin may be relevant to its modulatory effect on the host defense mechanism.
  3. An in vivo study of a locally-manufactured hydroxyapatite-based material as bone replacement material
    Abdul Razak NH, Al-Salihi KA, Samsudin AR
    Med J Malaysia, 2004 May;59 Suppl B:119-20.
    PMID: 15468847
    Defects were created in the mandible of a rabbit model whereby the right side was implanted with hydroxyapatite (HA) while the left side was left empty to act as control. Both the implant and control sites were evaluated clinically and histologically at 4,12,20,22 weeks. Decalcified sections were studied under confocal laser scanning microscope. No reactive cells were evident microscopically in all sections. There was bone ingrowth as early as 4 weeks when viewed by the topographic method. Enhancement of osteoconduction was evident by the presence of abundant capillaries, perivascular tissue and osteoprogenitor cells of the host. At 22 weeks, the implanted defect showed mature bone formation filling almost the whole field. This study demonstrated that the dense HA exhibits excellent biocompatibility as noted by the complete absence of reactive cells. It also promotes osteoconduction.
  4. Fulltext 1-[(Bromo-meth-yl)(phen-yl)meth-ylene]-2-(2,4-dinitro-phen-yl)hydrazine
    Salhin A, Abdul Razak N, Rahman IA
    Acta Crystallogr Sect E Struct Rep Online, 2009;65(Pt 6):o1221-2.
    PMID: 21583090 DOI: 10.1107/S1600536809016225
    The title compound, C(14)H(11)BrN(4)O(4), comprises two crystallographically independent mol-ecules (A and B) in the asymmetric unit. In mol-ecule B, intra-molecular bifurcated N-H⋯O and N-H⋯Br hydrogen bonds and in mol-ecule A, an intra-molecular N-H⋯O hydrogen bond generate S(6) ring motifs. The dihedral angle between the phenyl and benzene rings is 5.44 (6) in mol-ecule A and 7.63 (6)° in mol-ecule B. The ortho- and meta-nitro substituents make dihedral angles of 6.67 (15) and 2.26 (15)° to the attached benzene ring in mol-ecule A and 6.37 (17) and 5.81 (16)° in mol-ecule B. The Br atom in mol-ecule B is disordered over two positions with a refined site-occupancy ratio of 0.61 (3):0.39 (3). Inter-esting features of the crystal structure are the short Br⋯N [3.257 (3)-3.294 (4) Å], Br⋯O [3.279 (3)-3.307 (4) Å] and O⋯O [2.9319 (16)-2.9995 (16) Å] contacts, which are shorter than the sum of the van der Waals radii of these atoms. The crystal structure is further stabilized by inter-molecular C-H⋯O and π-π inter-actions [centroid-centroid distances = 3.6643 (8)-3.8514 (8) Å].
  5. Predictors of parenting stress in mothers of children with spina bifida
    Kanaheswari Y, Razak NN, Chandran V, Ong LC
    Spinal Cord, 2011 Mar;49(3):376-80.
    PMID: 20838404 DOI: 10.1038/sc.2010.125
    Prospective cross-sectional multidimensional study using clinical assessment and standard measures.
  6. Fulltext Bach adsorption study for the extraction of silver ions by hydrazone compounds from aqueous solution
    Mohamad Ali AS, Abdul Razak N, Ab Rahman I
    ScientificWorldJournal, 2012;2012:351967.
    PMID: 22629138 DOI: 10.1100/2012/351967
    Sorbent materials based on a hydrazone Schiff base compound, C(14)H(11)BrN(4)O(4), were prepared either by immobilizing the ligand into sol-gel (SG1) or bonding to silica (SG2). The sorbent materials were characterized by FT-IR, EDX, SEM, TEM, and TGA. The sorption characteristics of a matrix of eight transition metal ions (Ag(+), Cu(2+), Co(2+), Ni(2+), Fe(3+), Pb(2+), Zn(2+), and Mn(2+)) using batch method were studied. Several key parameters that affected the extraction efficiency such as pH, contact time, metal ions concentration, and gel size (for SGl) were investigated and optimized. Under the optimized conditions, the physically immobilized hydrazone sorbent (SG1) exhibits highest selectivity towards Ag(+) ions, while the chemically bonded hydrazone sorbent (SG2) exhibits high extraction for all metal ions tested. However, for practical applications such as the removal and preconcentration of Ag(+), the physically immobilized sorbent (SG1) is preferred.
  7. Kinematic comparison of the wrist movements that are possible with a biomechatronics wrist prosthesis and a body-powered prosthesis: a preliminary study
    Abd Razak NA, Abu Osman NA, Wan Abas WA
    Disabil Rehabil Assist Technol, 2013 May;8(3):255-60.
    PMID: 22830946 DOI: 10.3109/17483107.2012.704654
    This study examined the kinematic differences between a body-powered prosthesis and a biomechatronics prosthesis as a transradial amputee performed activities that involve flexion/extension and supination/pronation of the wrist.
  8. Survey of Patients with Cervical Cancer in Hospital UniversitiSains Malaysia: Survival Data Analysis with Time-Dependent Covariate
    Juhan N, Abd Razak N, Zubairi YZ, Khattak MN, Naing NN
    Iran J Public Health, 2013 Sep;42(9):980-7.
    PMID: 26175969
    BACKGROUND: Cervical cancer is the third most common cancer among women in Malaysia. The objective of this study was to estimate the effect of explanatory variables on survival time of cervical cancer patients receiving treatment at a hospital in Malaysia.

    METHODS: In this retrospective record review study, cervical cancer data obtained from Hospital UniversitiSains Malaysia (HUSM) was analysed. The data comprises of 120 patients who had been diagnosed as cervical cancer between 1(st) July 1995 and 30(th) June 2007, and obtained treatment from the hospital. The outcome variable was survival time (in months) from cervical cancer diagnosis to death. A stratified Weibull model was applied to study the effect of explanatory variable on survival time when there was time-dependent covariate in the model.

    RESULTS: Stage of disease and metastases were important prognostic variables. However, metastasis had been stratified because this variable did not satisfy the proportional hazard assumption. In without metastasis stratum, patients who were diagnosed at stage III & IV are at 2.30 times the risk of death as those in stage I & II. Meanwhile, in with metastasis stratum, patients in stage III & IV group had 3.53 times the hazard faced by patients in stage I & II.

    CONCLUSION: The prognosis of cervical cancer patients was dependent upon the stage at diagnosis, after the stratification of the metastasis variable. A poorer prognosis on survival was observed for patients in stage III & IV than those in stage I & II.

  9. Transtibial prosthesis suspension systems: systematic review of literature
    Gholizadeh H, Abu Osman NA, Eshraghi A, Ali S, Razak NA
    Clin Biomech (Bristol, Avon), 2014 Jan;29(1):87-97.
    PMID: 24315710 DOI: 10.1016/j.clinbiomech.2013.10.013
    Today a number of prosthetic suspension systems are available for transtibial amputees. Consideration of an appropriate suspension system can ensure that amputee's functional needs are satisfied. The higher the insight to suspension systems, the easier would be the selection for prosthetists. This review attempted to find scientific evidence pertaining to various transtibial suspension systems to provide selection criteria for clinicians.
  10. Thermokinetic comparison of trypan blue decolorization by free laccase and fungal biomass
    Razak NN, Annuar MS
    Appl Biochem Biotechnol, 2014 Mar;172(6):2932-44.
    PMID: 24464534 DOI: 10.1007/s12010-014-0731-7
    Free laccase and fungal biomass from white-rot fungi were compared in the thermokinetics study of the laccase-catalyzed decolorization of an azo dye, i.e., Trypan Blue. The decolorization in both systems followed a first-order kinetics. The apparent first-order rate constant, k1', value increases with temperature. Apparent activation energy of decolorization was similar for both systems at ∼ 22 kJ mol(-1), while energy for laccase inactivation was 18 kJ mol(-1). Although both systems were endothermic, fungal biomass showed higher enthalpy, entropy, and Gibbs free energy changes for the decolorization compared to free laccase. On the other hand, free laccase showed reaction spontaneity over a wider range of temperature (ΔT = 40 K) as opposed to fungal biomass (ΔT = 15 K). Comparison of entropy change (ΔS) values indicated metabolism of the dye by the biomass.
  11. Satisfaction and problems experienced with wrist movements: comparison between a common body-powered prosthesis and a new biomechatronics prosthesis
    Abd Razak NA, Abu Osman NA, Kamyab M, Wan Abas WA, Gholizadeh H
    Am J Phys Med Rehabil, 2014 May;93(5):437-44.
    PMID: 24429510 DOI: 10.1097/PHM.0b013e3182a51fc2
    This report compares wrist supination and pronation and flexion and extension movements with the common body-powered prosthesis and a new biomechatronics prosthesis with regard to patient satisfaction and problems experienced with the prosthesis. Fifteen subjects with traumatic transradial amputation who used both prosthetic systems participated in this study. Each subject completed two questionnaires to evaluate their satisfaction and problems experienced with the two prosthetic systems. Satisfaction and problems with the prosthetic's wrist movements were analyzed in terms of the following: supination and pronation; flexion and extension; appearance; sweating; wounds; pain; irritation; pistoning; smell; sound; durability; and the abilities to open a door, hold a cup, and pick up or place objects. This study revealed that the respondents were more satisfied with the biomechatronics wrist prosthesis with regard to supination and pronation, flexion and extension, pain, and the ability to open a door. However, satisfaction with the prosthesis showed no significant differences in terms of sweating, wounds, irritation, pistoning, smell, sound, and durability. The abilities to hold a cup and pick up or place an object were significantly better with the body-powered prosthesis. The results of the survey suggest that satisfaction and problems with wrist movements in persons with transradial amputation can be improved with a biomechatronics wrist prosthesis compared with the common body-powered prosthesis.
  12. Thermoluminescence properties of lithium magnesium borate glasses system doped with dysprosium oxide
    Mhareb MH, Hashim S, Ghoshal SK, Alajerami YS, Saleh MA, Razak NA, et al.
    Luminescence, 2015 Dec;30(8):1330-5.
    PMID: 25828828 DOI: 10.1002/bio.2902
    We report the impact of dysprosium (Dy(3+)) dopant and magnesium oxide (MgO) modifier on the thermoluminescent properties of lithium borate (LB) glass via two procedures. The thermoluminescence (TL) glow curves reveal a single prominent peak at 190 °C for 0.5 mol% of Dy(3+). An increase in MgO contents by 10 mol% enhances the TL intensity by a factor of 1.5 times without causing any shift in the maximum temperature. This enhancement is attributed to the occurrence of extra electron traps created via magnesium and the energy transfer to trivalent Dy(3+) ions. Good linearity in the range of 0.01-4 Gy with a linear correlation coefficient of 0.998, fading as low as 21% over a period of 3 months, excellent reproducibility without oven annealing and tissue equivalent effective atomic numbers ~8.71 are achieved. The trap parameters, including geometric factor (μg), activation energy (E) and frequency factor (s) associated with LMB:Dy are also determined. These favorable TL characteristics of prepared glasses may contribute towards the development of Li2O-MgO-B2O3 radiation dosimeters.
  13. Fulltext Characteristics associated with the consumption of malted drinks among Malaysian primary school children: findings from the MyBreakfast study
    Jan Mohamed HJ, Loy SL, Mohd Taib MN, Karim NA, Tan SY, Appukutty M, et al.
    BMC Public Health, 2015;15:1322.
    PMID: 26718818 DOI: 10.1186/s12889-015-2666-5
    The consumption of beverages contributes to diet quality and overall nutrition. Studies on malted drinks, one of the widely consumed beverage choices among children in Asia, however, have received limited attention. This study aimed to examine the prevalence of malted drink consumption and explored associations of sociodemographic characteristics, nutrient intakes, weight status and physical activity levels with malted drink consumption among primary school children in Malaysia.
  14. Quality of Kelantan drinking water and knowledge, attitude and practice among the population of Pasir Mas, Malaysia
    Ab Razak NH, Praveena SM, Aris AZ, Hashim Z
    Public Health, 2016 Feb;131:103-11.
    PMID: 26715317 DOI: 10.1016/j.puhe.2015.11.006
    Information about the quality of drinking water, together with analysis of knowledge, attitude and practice (KAP) analysis and health risk assessment (HRA) remain limited. The aims of this study were: (1) to ascertain the level of KAP regarding heavy metal contamination of drinking water in Pasir Mas; (2) to determine the concentration of heavy metals (Al, Cr, Cu, Fe, Ni, Pb, Zn and Cd) in drinking water in Pasir Mas; and (3) to estimate the health risks (non-carcinogenic and carcinogenic) caused by heavy metal exposure through drinking water using hazard quotient and lifetime cancer risk.
  15. Photoluminescence and thermoluminescence properties of Li2 O-Na2 O-B2 O3 glass
    Razak NA, Hashim S, Mhareb MH, Tamchek N
    Luminescence, 2016 May;31(3):754-9.
    PMID: 26333749 DOI: 10.1002/bio.3020
    Influence of Nd(3+) concentration on the optical and thermoluminescence (TL) properties of melt-annealed synthesized 10 Na2 O: 20 Li2 O: (70-x) B2 O3 : xNd2 O3 , where 0.1≤ x ≤0.7 (LNB) glasses are determined. The absence of sharp peaks in X-ray diffraction patterns confirms the amorphous nature of the prepared glasses. The photoluminescence spectra under 800 nm laser excitations at room temperature exhibit three prominent peaks centred at 538, 603 and 675 nm corresponding to the transitions of (4) G7/2 → (4) I9/2 , [(4) G7/2 → (4) I11/2 , (4) G5/2 → (4) I9/2 ] and [(4) G7/2 → (4) I13/2 , (4) G5/2 → (4) I11/2 ], respectively. The TL glow curve exhibits a prominent peak (Tm ) at 180°C. The best performance of the prepared glass was found at 0.5 mol% of Nd2 O3 . We achieved a good linearity of TL response against dose between 0.5 to 4.0 Gy. The calculated value of the effective atomic number, Zeff , is 7.55 which is nearly tissue equivalent (Zeff = 7.42). These promising features demonstrate the capability of the aforementioned glass to be used as a radiation dosimeter. Copyright © 2015 John Wiley & Sons, Ltd.
  16. Fulltext Discrepancy in blood pressure between the left and right arms - importance of clinical diagnosis and role of radiological imaging
    Kuan PX, Tan PW, Jobli AT, Abd Razak N
    Med J Malaysia, 2016 Aug;71(4):206-208.
    PMID: 27770122 MyJurnal
    Differences in systolic blood pressure reading between arms are common but could signal trouble if the discrepancy is significant. Early detection of aortic dissection could invariably determine patient's survivability. Hence, a high index of suspicion with prompt diagnostic imaging is vital for accurate diagnosis.
  17. Fulltext Turbulence Model Selection for Low Reynolds Number Flows
    Aftab SM, Mohd Rafie AS, Razak NA, Ahmad KA
    PLoS One, 2016;11(4):e0153755.
    PMID: 27104354 DOI: 10.1371/journal.pone.0153755
    One of the major flow phenomena associated with low Reynolds number flow is the formation of separation bubbles on an airfoil's surface. NACA4415 airfoil is commonly used in wind turbines and UAV applications. The stall characteristics are gradual compared to thin airfoils. The primary criterion set for this work is the capture of laminar separation bubble. Flow is simulated for a Reynolds number of 120,000. The numerical analysis carried out shows the advantages and disadvantages of a few turbulence models. The turbulence models tested were: one equation Spallart Allmars (S-A), two equation SST K-ω, three equation Intermittency (γ) SST, k-kl-ω and finally, the four equation transition γ-Reθ SST. However, the variation in flow physics differs between these turbulence models. Procedure to establish the accuracy of the simulation, in accord with previous experimental results, has been discussed in detail.
  18. Fulltext Detection of α-thalassaemia in neonates on cord blood and dried blood spot samples by capillary electrophoresis
    Alauddin H, Langa M, Mohd Yusoff M, Raja Sabudin RZA, Ithnin A, Abdul Razak NF, et al.
    Malays J Pathol, 2017 Apr;39(1):17-23.
    PMID: 28413201 MyJurnal
    INTRODUCTION: Haemoglobin Bart's (Hb Bart's) level is associated with α-thalassaemia traits in neonates, enabling early diagnosis of α-thalassaemia. The study aimed to detect and quantify the Hb Bart's using Cord Blood (CB) and CE Neonat Fast Hb (NF) progammes on fresh and dried blood spot (DBS) specimen respectively by capillary electrophoresis (CE).

    METHODS: Capillarys Hemoglobin (E) Kit (for CB) and Capillarys Neonat Hb Kit (for NF) were used to detect and quantify Hb Bart's by CE in fresh cord blood and dried blood spot (DBS) specimens respectively. High performance liquid chromatography (HPLC) using the β-Thal Short Programme was also performed concurrently with CE analysis. Confirmation was obtained by multiplex ARMS Gap PCR.

    RESULTS: This study was performed on 600 neonates. 32/600 (5.3%) samples showed presence of Hb Bart's peak using the NF programme while 33/600 (5.5%) were positive with CB programme and HPLC methods. The range of Hb Bart's using NF programme and CB programme were (0.5-4.1%) and (0.5-7.1%), respectively. Molecular analysis confirmed all positive samples possessed α-thalassaemia genetic mutations, with 23/33 cases being αα/--SEA, four -α3.7/-α3.7, two αα/-α3.7 and three αα/ααCS. Fifty Hb Bart's negative samples were randomly tested for α-genotypes, three were also found to be positive for α-globin gene mutations. Thus, resulting in sensitivity of 91.7% and 88.9% and specificity of 100% for the Capillarys Cord Blood programme and Capillarys Neonat Fast programme respectively.

    CONCLUSION: Both CE programmes using fresh or dried cord blood were useful as a screening tool for α-thalassaemia in newborns. All methods show the same specificity (100%) with variable, but acceptable sensitivities in the detection of Hb Bart.
  19. A retrospective analysis of the relationship between facial injury and mild traumatic brain injury
    Abdul Razak N, Nordin R, Abd Rahman N, Ramli R
    Dent Traumatol, 2017 Oct;33(5):400-405.
    PMID: 28649703 DOI: 10.1111/edt.12355
    BACKGROUND/AIMS: The association between facial injury characteristics and mild traumatic brain injury (mTBI) is unclear. The aim of this study was to determine the association between facial injury characteristics and mTBI.

    METHODS: A retrospective review utilizing patients' medical records at the Universiti Kebangsaan Malaysia Medical Centre (UKMMC), Kuala Lumpur, Malaysia, was performed. Records of subjects with a history of facial trauma from 1 April 2012 to 31 December 2012 were selected. Various levels and surgical speciality records were reviewed to ascertain the diagnoses of facial injuries and mTBI.

    RESULTS: A total of 348 medical records with the diagnosis of facial injuries were included. The prevalence of mTBI among these patients was 41.4% (95% CI 36.2-46.6). The majority of the patients with mTBI were in the age group of 18-25 years old. Patients with or without facial lacerations that were located on the lower face had a significant association with mTBI, P=.001, compared to other types of soft tissue injury. In addition, a statistically significant association was observed between facial fractures occurring to the middle face and mTBI, P=.018. Pearson chi-square test also showed statistically significant association between the severity of facial injuries and mTBI, P=.018.

    CONCLUSIONS: Mild traumatic brain injury should be suspected in patients with facial injuries and particularly those with lower face lacerations, midface fractures, moderate to severe facial injury and presence of multiple injuries.

  20. Effect of different stent configurations using Lattice Boltzmann method and particles image velocimetry on artery bifurcation aneurysm problem
    Mokhtar NH, Abas A, Razak NA, Hamid MNA, Teong SL
    J Theor Biol, 2017 11 21;433:73-84.
    PMID: 28844907 DOI: 10.1016/j.jtbi.2017.08.016
    Proper design of stent for application at specific aneurysm effect arteries could help to reduce the issues with thrombosis and aneurysm. In this paper, four types of stent configuration namely half-Y (6 mm), half-Y (4 mm), cross-bar, and full-Y configuration will implanted on real 3D artery bifurcation aneurysm effected arteries. Comparisons were then conducted based on the flow patterns after stent placement using both LBM-based solver and PIV experimental findings. According to the data obtained from all 4 stent designs, the flow profiles and the computed velocity from both methods were in agreement with each other. Both methods found that half-Y (6 mm) stent configuration is by far the best configuration in reducing the blood velocity at the vicinity of the aneurysm sac. The analysis also show that the half-Y (6 mm) stent configuration recorded the highest percentage of velocity reduction and managed to substantially reduce the pressure at the bifurcation region. This high flow velocity reduction through the use of half-Y stent could consequently promote the formation of thrombus thereby reducing the risk of rupture in the aneurysm sac.
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