Displaying publications 1 - 20 of 66 in total

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  1. ANN modeling of the penetration across a polydimethylsiloxane membrane from theoretically derived molecular descriptors
    Agatonovic-Kustrin S, Beresford R, Yusof AP
    J Pharm Biomed Anal, 2001 Sep;26(2):241-54.
    PMID: 11470201
    A quantitative structure-permeability relationship was developed using Artificial Neural Network (ANN) modeling to study penetration across a polydimethylsiloxane membrane. A set of 254 compounds and their experimentally derived maximum steady state flux values used in this study was gathered from the literature. A total of 42 molecular descriptors were calculated for each compound. A genetic algorithm was used to select important molecular descriptors and supervised ANN was used to correlate selected descriptors with the experimentally derived maximum steady-state flux through the polydimethylsiloxane membrane (log J). Calculated molecular descriptors were used as the ANN's inputs and log J as the output. Developed model indicates that molecular shape and size, inter-molecular interactions, hydrogen-bonding capacity of drugs, and conformational stability could be used to predict drug absorption through skin. A 12-descriptor nonlinear computational neural network model has been developed for the estimation of log J values for a data set of 254 drugs. Described model does not require experimental parameters and could potentially provide useful prediction of membrane penetration of new drugs and reduce the need for actual compound synthesis and flux measurements.
    Matched MeSH terms: Coated Materials, Biocompatible/chemistry*
  2. Plasma-sprayed coating of hydroxyapatite on metal implants--a review
    Talib RJ, Toff MR
    Med J Malaysia, 2004 May;59 Suppl B:153-4.
    PMID: 15468864
    Metal implants such as titanium, stainless steel and Co-Cr-Mo are used for load bearing purposes such as hip joint prostheses, fixing plates and dental root implants. For practical application, plasma-sprayed coatings of hydroxyapatite (HA) on metal implants are applied to promote early formation of strong bonds between metal implant and living bone. Plasma spray coating involves heating of HA material to a semi-molten or molten state and then propels its to a metal substrate. The plasma flame temperature is in the range of 6,000 degrees C to 16,000 degrees C but the surface temperature of the substrate rarely exceeds 150 degrees C. The HA materials are feed into the spray gun in the form of powders. Furthermore, this paper will discuss the processes of plasma-sprayed coating of HA on various types of metal implants.
    Matched MeSH terms: Coated Materials, Biocompatible*
  3. Predicting graded young modulus values of Ti alloys modified by ion implantation
    Hassan MH
    Med J Malaysia, 2004 May;59 Suppl B:164-5.
    PMID: 15468869
    There has been, and is still, concern about the high elastic modulus of Ti alloys compared to bone. Any reduction in the Young's modulus value of the implant is expected to enhance stress redistribution to the adjacent bone tissues, minimize stress shielding and eventually prolong device lifetime. Dynamic Monte Carlo simulation is used to predict the gradual reduction in Young's modulus values between the bulk of Ti alloys and the modified surface layers due to Ca ion implantation. The simulation can be used as a screening step when applying new alloys and/or coatings.
    Matched MeSH terms: Coated Materials, Biocompatible/analysis*
  4. A comparative study of osseointegration phenomenon in coated and non-coated NiTi implants in a rabbit model
    Najafpour HD, Suzina AH, Nizam A, Samsudin AR
    Med J Malaysia, 2004 May;59 Suppl B:121-2.
    PMID: 15468848
    There was a significant increased in Absolute Contact Length measurements of endosteal bone growth along the Nickel-Titanium (NiTi) implant coated with the natural coral powder and Hydroxyapatite (HA) compared to the non-calcium coated implants. This study demonstrated that coated implants seemed to show earlier and higher osseointergration phenomena compared to non coated ones. Furthermore, there was significantly greater bone-to-implant contact at the apical 1/3rd of the coated implants.
    Matched MeSH terms: Coated Materials, Biocompatible*
  5. Endothelialisation of poly (carbonate-siloxane-urea) urethane
    Kannan RY, Sales KM, Salacinski HJ, Butler PE, Seifalian AM
    Med J Malaysia, 2004 May;59 Suppl B:107-8.
    PMID: 15468841
    Matched MeSH terms: Coated Materials, Biocompatible*
  6. Factors inducing in-stent restenosis: an in-vitro model
    Santin M, Morris C, Harrison M, Mikhalovska L, Lloyd AW, Mikhalovsky S
    Med J Malaysia, 2004 May;59 Suppl B:93-4.
    PMID: 15468834
    In-stent restenosis is caused by the proliferation of the smooth muscle cells (SMCs) following a host response towards the implanted device. However, the precise biochemical and cellular mechanisms are still not completely understood. In this paper, the behaviour of SMCs has been investigated by an in vitro model where the cells were stimulated by platelet derived growth factor (PDGF) on tissue-like substrates as well as on biomaterials such as stainless steel (St) and diamond-like carbon (DLC)-coated St. The results demonstrated that SMCs have a completely different adhesion mode on St and become particularly prone to proliferation and pro-inflammatory cytokine secretion under PDGF stimulus. This would suggest that restenosis may caused by the accidental contact of the SMC with the St substrate under an inflammatory insult.
    Matched MeSH terms: Coated Materials, Biocompatible
  7. Fulltext Use of gentamicin impregnated POP discs for antibiotic pouch dressing
    Lau CP, Chee EK, Thirumal M
    Med J Malaysia, 2006 Dec;61 Suppl B:32-6.
    PMID: 17600990
    Antibiotic pouch technique is commonly used due to the high local antibiotic concentration and moist environment for wound healing. We used locally made gentamicin impregnated Plaster of Paris discs in treating wounds with exposed deep structures like tendons and bones. Out of 22 patients treated with this method, 19 completed treatment. Granulation tissue formed quickly and effectively covered the exposed structures. All wounds either healed by secondary intention or became suitable for split skin grafting. Gentamicin impregnated Plaster of Paris disc pouch dressing is safe, cost saving, and effective for management of deep open wounds.
    Matched MeSH terms: Coated Materials, Biocompatible*
  8. Enhancement of fluoride release from glass ionomer cement following a coating of silver fluoride
    Ariffin Z, Ngo H, McIntyre J
    Aust Dent J, 2006 Dec;51(4):328-32.
    PMID: 17256308
    BACKGROUND: This study investigated the extent to which a coating of 10% silver fluoride (AgF) on discs of glass jonomer cements (GIGs) would enhance the release of fluoride ion into eluting solutions at varying pH.

    MATERIALS AND METHODS: Forty discs each of Fuji LX, Fuji VII and of Vitrebond were prepared in a plastic mould. Twenty discs of each material were coated for 30 seconds with a 10% solution of AgF. Five discs each of coated and uncoated material were placed individually in 4m1 of differing eluant solutions. The eluant solutions comprised deionized distilled water (DDW) and three separate acetate buffered solutions at pH 7, pH 5 and pH 3. After 30 minutes the discs were removed and placed in five vials containing 4m1 of the various solutions for a further 30 minutes. This was repeated for further intervals of time up to 216 hours, and all eluant solutions were stored. Fluoride concentrations in the eluant solutions were estimated using a fluoride specific electrode, with TISAB IV as a metal ion complexing and ionic concentration adjustment agent. Cumulative fluoride release patterns were determined from the incremental data.

    RESULTS: The coating of AgF greatly enhanced the level of fluoride ion release from all materials tested. Of the uncoated samples, Vitrehond released the greater concentrations of fluoride ion, followed by Fuji VII. However, cumulative levels of fluoride released from coated samples of the GICs almost matched those from coated Vitrebond.

    CONCLUSIONS: It was concluded that a coating of 10% AgF on GICs and a resin modified GIC greatly enhanced the concentration of fluoride released from these materials. This finding might be applied to improving protection against recurrent caries, particularly in high caries risk patients, and in the atraumatic restorative technique (ART) of restoration placement.

    Matched MeSH terms: Coated Materials, Biocompatible
  9. Effects of fluoride-modified titanium surfaces on osteoblast proliferation and gene expression
    Isa ZM, Schneider GB, Zaharias R, Seabold D, Stanford CM
    Int J Oral Maxillofac Implants, 2006 Mar-Apr;21(2):203-11.
    PMID: 16634490
    PURPOSE: The objective of this study was to test the hypothesis that fluoride-modified titanium surfaces would enhance osteoblast differentiation. Osteoblast growth on a moderately rough etched fluoride-modified titanium surface (alteration in cellular differentiation) was compared to osteoblast growth on the same surface grit-blasted with titanium dioxide. The potential role of nanometer-level alterations on cell shape and subsequent differentiation was then compared.
    MATERIALS AND METHODS: Human embryonic palatal mesenchymal (HEPM) cultures were incubated on the respective surfaces for 1, 3, and 7 days, followed by analysis for cell proliferation, alkaline phosphatase (ALP) -specific activity, and mRNA steady-state expression for bone-related genes (ALP, type I collagen, osteocalcin, bone sialoprotein [BSP] II, Cbfa1, and osterix) by real-time polymerase chain reaction (PCR).
    RESULTS: The different surfaces did not alter the mRNA expression for ALP, type I collagen, osterix, osteocalcin, or BSP II. However, Cbfa1 expression on the fluoride-modified titanium surface was significantly higher (P < .001) at 1 week. The number of cells on this surface was 20% lower than the number of cells on the surface TiO2-blasted with 25-microm particles but not significantly different from the number of cells on the surface TiO2-blasted with 125-microm particles. Cells grown on all the titanium surfaces expressed similar levels of ALP activity.
    CONCLUSIONS: The results indicated that a fluoride-modified surface topography, in synergy with surface roughness, may have a greater influence on the level of expression of Cbfa1 (a key regulator for osteogenesis) than the unmodified titanium surfaces studied.
    Matched MeSH terms: Coated Materials, Biocompatible/pharmacology
  10. Investigation on mechanical properties of contemporary metallic bone plates: towards the development of composite bone plates
    Hoque ME, Zainal NH, Syarif J
    Med J Malaysia, 2008 Jul;63 Suppl A:91-2.
    PMID: 19024999
    This study aims at investigating the mechanical properties of the contemporary metallic bone plates determining the effect of their length, width and thickness on the properties and compares with the composite bone plates. Three-points bending test was performed over the stainless steel plates of different length, width and thickness. The test results showed that different plates had different mechanical properties. However, the properties are still much higher than that of particular bones intended to be treated. Therefore, the reported findings strongly encourage developing composite bone plates with biocompatible polymers/fibers that would have modulated properties according to the requirements.
    Matched MeSH terms: Coated Materials, Biocompatible
  11. A novel hydrothermal process to produce hydroxyapatite powders
    Sopyan I, Rosli A, Raihana MF
    Med J Malaysia, 2008 Jul;63 Suppl A:81-2.
    PMID: 19024994
    A novel hydrothermal process has been developed various hydroxyapatite(HA) powder. The HA powder was investigated in different calcination temperatures over the range of 200 degrees C-800 degrees C. TG/DTA and XRD analysis revealed that at temperatures of 700-800 degrees C the decomposition processes and phase changes took place. It is due to the appearance of TCP phase substituting the HA phase. FESEM observation showed that the produced hydroxyapatite powder was extraordinarily fine with nanosize primary particles and almost evenly spherical in shaped. Its high purity proved that the powder fulfills medical requirement.
    Matched MeSH terms: Coated Materials, Biocompatible/chemistry
  12. Influence of manganese doping into HA powders on the properties of its dense bodies
    Natasha AN, Sopyan I, Mel M, Ramesh S
    Med J Malaysia, 2008 Jul;63 Suppl A:85-6.
    PMID: 19024996
    The effect of Manganese (Mn) addition on the Vickers hardness and relative density of nanocrystalline hydroxyapatite (HA) dense bodies were studied. The starting Mn doped HA powders was synthesized via sol-gel method with Mn concentration varies from 2 mol% up to 15 mol% Mn. The Mn doped HA disc samples were prepared by uniaxial pressing at 200MPa and subsequently sintered at 1300 degrees C. Characterization was carried out where appropriate to determine the phases present, bulk density, Vickers hardness of the various content of Mn doped HA dense bodies. The addition of Mn was observed to influence the color appearance of the powders and dense bodies as well. Higher Mn concentration resulted in dark grey powders. It was also found that the hardness and relative density of the material increased as the Mn content increased and influenced by the crystallinity of the prepared Mn doped HA powders.
    Matched MeSH terms: Coated Materials, Biocompatible/chemical synthesis; Coated Materials, Biocompatible/chemistry
  13. Surface properties of Indonesian-made narrow dynamic compression plates
    Dewo P, Sharma PK, van der Tas HF, van der Houwen EB, Timmer M, Magetsari R, et al.
    Med J Malaysia, 2008 Jul;63 Suppl A:21-2.
    PMID: 19024964
    The enormous need of orthopaedic (surgical) implants such as osteosynthesis plates is difficult to be fulfilled in developing countries commonly rely on imported ones. One of the alternatives is utilization of local resources, but only after they have been proven safe to use, to overcome this problem. Surface properties are some of the determining factors of safety for those implants. We have succeeded in developing prototype of osteosynthesis plate and the results indicate that Indonesian-made plates need improvement with regards to the surface quality of physical characterization.
    Matched MeSH terms: Coated Materials, Biocompatible
  14. Removal of chromium hexavalent ion from aqueous solutions using biopolymer chitosan coated with poly 3-methyl thiophene polymer
    Hena S
    J Hazard Mater, 2010 Sep 15;181(1-3):474-9.
    PMID: 20627405 DOI: 10.1016/j.jhazmat.2010.05.037
    Adsorption capacity of Cr(VI) onto chitosan coated with poly 3-methyl thiophene synthesized chemically was investigated in a batch system by considering the effects of various parameters like contact time, initial concentration, pH and temperature. Cr(VI) removal is pH dependent and found to be maximum at pH 2.0. Increases in adsorption capacity with increase in temperature indicate that the adsorption reaction is endothermic. Based on this study, the thermodynamic parameters like standard Gibb's free energy (DeltaG degrees), standard enthalpy (DeltaH degrees) and standard entropy (DeltaS degrees) were evaluated. Adsorption kinetics of Cr(VI) ions onto chitosan coated with poly 3-methyl thiophene were analyzed by pseudo-first-order and pseudo-second-order models. The Langmuir, Freundlich and Temkin isotherms were used to describe the adsorption equilibrium studies of chitosan coated with poly 3-methyl thiophene at different temperatures. Langmuir isotherm shows better fit than Freundlich and Temkin isotherms in the temperature range studied. The results show that the chitosan coated with poly 3-methyl thiophene can be efficiently used for the treatment of wastewaters containing chromium as a low cost alternative compared to commercial activated carbon and other adsorbents reported. In order to find out the possibility of regeneration and reuse of exhausted adsorbent, desorption studies were also performed.
    Matched MeSH terms: Coated Materials, Biocompatible/chemistry*
  15. Paclitaxel-eluting balloon angioplasty and cobalt-chromium stents versus conventional angioplasty and paclitaxel-eluting stents in the treatment of native coronary artery stenoses in patients with diabetes mellitus
    Ali RM, Degenhardt R, Zambahari R, Tresukosol D, Ahmad WA, Kamar Hb, et al.
    EuroIntervention, 2011 May;7 Suppl K:K83-92.
    PMID: 22027736 DOI: 10.4244/EIJV7SKA15
    Coronary lesions in diabetics (DM) are associated with a high recurrence following percutaneous coronary intervention (PCI), even after drug-eluting stent (DES) deployment. Encouraging clinical data of the drug-eluting balloon catheter (DEB) SeQuent Please warrant its investigation in these patients.
    Matched MeSH terms: Coated Materials, Biocompatible*
  16. In-stent restenosis: the gold standard has changed
    Chin K
    EuroIntervention, 2011 May;7 Suppl K:K43-6.
    PMID: 22027726 DOI: 10.4244/EIJV7SKA7
    In-stent restenosis remains an important issue even in the drug-eluting stent (DES) era today. In recent years, drug-eluting balloons (DEB) have emerged as a potential alternative to the treatment of in-stent restenosis. Paclitaxel was identified as the primary drug for DEB because of its rapid uptake and prolonged retention. Non-stent-based local drug delivery using DEB maintains the antiproliferation properties of DES, but without the limitations of DES such as subacute stent thrombosis, stent fractures, prolonged antiplatelet therapy and more importantly, avoiding a "stent-in-a-stent" approach. The first major impact of drug-eluting balloon (DEB) in the management of bare metal instent restenosis was the "PACCOCATH ISR I" randomised trial, comparing the efficacy of drug-eluting balloon versus uncoated balloon. The six months angiographic results showed a binary restenosis of 5% and 4% MACE in the drug-eluting balloon group, compared with 43% binary restenosis and 31% MACE, in the uncoated balloon group (p=0.002 and 0.02). The second major DEB trial is the "PEPCAD II Trial", comparing the efficacy of the SeQuent Please DEB with the Taxus drug-eluting stent in the treatment of bare-metal stent instent restenosis. At 6-month follow-up, in-segment late lumen loss was 0.38 ± 0.61 mm in the DES group versus 0.17 ± 0.42 mm (p=0.03) in the DEB group, resulting in a binary restenosis rate of 12/59 (20%) versus 4/57 (7%; p=0.06). At 12 months, MACE rates were 22% in the Taxus group and 9% in the DEB group (P=0.08). The TLR at 12 months was 15% in the Taxus group and 6% in the DEB group (p=0.15). Based on these two pivotal trials, the European Society of Cardiology Guidelines for Percutaneous Coronary Intervention (2010) recommended that DEB should be considered for the treatment of in-stent restenosis after prior bare-metal stent. This was accorded a class 2 IIa indication, with a level B evidence.
    Matched MeSH terms: Coated Materials, Biocompatible*
  17. Drug-eluting balloons: future potential indications and applications
    Choo GH
    EuroIntervention, 2011 May;7 Suppl K:K112-8.
    PMID: 22027720 DOI: 10.4244/EIJV7SKA19
    The drug-eluting balloon (DEB) is an exciting new technology that holds much promise. As an evolving technology undergoing intensive research, the device is being constantly refined and its numerous potential applications studied. Though initially created to fulfil specific needs in the coronary vasculature, there is great potential for its use in other vascular territories and structures including the management of valvular, congenital heart and neuro-interventional pathologies. In addition, the application of this device in conjunction with other existing technologies may enhance the clinical results.
    Matched MeSH terms: Coated Materials, Biocompatible*
  18. Fulltext Preparation of Fe₃O₄ magnetic nanoparticles coated with gallic acid for drug delivery
    Dorniani D, Hussein MZ, Kura AU, Fakurazi S, Shaari AH, Ahmad Z
    Int J Nanomedicine, 2012;7:5745-56.
    PMID: 23166439 DOI: 10.2147/IJN.S35746
    Magnetic iron oxide nanoparticles were prepared using a sonochemical method under atmospheric conditions at a Fe²⁺ to Fe³⁺ molar ratio of 1:2. The iron oxide nanoparticles were subsequently coated with chitosan and gallic acid to produce a core-shell structure.
    Matched MeSH terms: Coated Materials, Biocompatible/chemical synthesis*; Coated Materials, Biocompatible/toxicity
  19. Fabrication and deformation behaviour of multilayer Al2O3/Ti/TiO2 nanotube arrays
    Baradaran S, Basirun WJ, Zalnezhad E, Hamdi M, Sarhan AA, Alias Y
    J Mech Behav Biomed Mater, 2013 Apr;20:272-82.
    PMID: 23453827 DOI: 10.1016/j.jmbbm.2013.01.020
    In this study, titanium thin films were deposited on alumina substrates by radio frequency (RF) magnetron sputtering. The mechanical properties of the Ti coatings were evaluated in terms of adhesion strength at various RF powers, temperatures, and substrate bias voltages. The coating conditions of 400W of RF power, 250°C, and a 75V substrate bias voltage produced the strongest coating adhesion, as obtained by the Taguchi optimisation method. TiO2 nanotube arrays were grown as a second layer on the Ti substrates using electrochemical anodisation at a constant potential of 20V and anodisation times of 15min, 45min, and 75min in a NH4F electrolyte solution (75 ethylene glycol: 25 water). The anodised titanium was annealed at 450°C and 650°C in a N2 gas furnace to obtain different phases of titania, anatase and rutile, respectively. The mechanical properties of the anodised layer were investigated by nanoindentation. The results indicate that Young's modulus and hardness increased with annealing temperature to 650°C.
    Matched MeSH terms: Coated Materials, Biocompatible/chemistry*
  20. Polylactic-co-glycolic acid mesh coated with fibrin or collagen and biological adhesive substance as a prefabricated, degradable, biocompatible, and functional scaffold for regeneration of the urinary bladder wall
    Salem SA, Hwei NM, Bin Saim A, Ho CC, Sagap I, Singh R, et al.
    J Biomed Mater Res A, 2013 Aug;101(8):2237-47.
    PMID: 23349110 DOI: 10.1002/jbm.a.34518
    The chief obstacle for reconstructing the bladder is the absence of a biomaterial, either permanent or biodegradable, that will function as a suitable scaffold for the natural process of regeneration. In this study, polylactic-co-glycolic acid (PLGA) plus collagen or fibrin was evaluated for its suitability as a scaffold for urinary bladder construct. Human adipose-derived stem cells (HADSCs) were cultured, followed by incubation in smooth muscle cells differentiation media. Differentiated HADSCs were then seeded onto PLGA mesh supported with collagen or fibrin. Evaluation of cell-seeded PLGA composite immersed in culture medium was performed under a light and scanning microscope. To determine if the composite is compatible with the urodynamic properties of urinary bladder, porosity and leaking test was performed. The PLGA samples were subjected to tensile testing was pulled until PLGA fibers break. The results showed that the PLGA composite is biocompatible to differentiated HADSCs. PLGA-collagen mesh appeared to be optimal as a cell carrier while the three-layered PLGA-fibrin composite is better in relation to its leaking/ porosity property. A biomechanical test was also performed for three-layered PLGA with biological adhesive and three-layered PLGA alone. The tensile stress at failure was 30.82 ± 3.80 (MPa) and 34.36 ± 2.57 (MPa), respectively. Maximum tensile strain at failure was 19.42 ± 2.24 (mm) and 23.06 ± 2.47 (mm), respectively. Young's modulus was 0.035 ± 0.0083 and 0.043 ± 0.012, respectively. The maximum load at break was 58.55 ± 7.90 (N) and 65.29 ± 4.89 (N), respectively. In conclusion, PLGA-Fibrin fulfils the criteria as a scaffold for urinary bladder reconstruction.
    Matched MeSH terms: Coated Materials, Biocompatible/chemistry*
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