Displaying publications 41 - 60 of 145 in total

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  1. Fulltext Ultra-structural changes and expression of chondrogenic and hypertrophic genes during chondrogenic differentiation of mesenchymal stromal cells in alginate beads
    Dashtdar H, Murali MR, Selvaratnam L, Balaji Raghavendran H, Suhaeb AM, Ahmad TS, et al.
    PeerJ, 2016;4:e1650.
    PMID: 26966647 DOI: 10.7717/peerj.1650
    Chondrogenic differentiation of mesenchymal stromal cells (MSCs) in the form of pellet culture and encapsulation in alginate beads has been widely used as conventional model for in vitro chondrogenesis. However, comparative characterization between differentiation, hypertrophic markers, cell adhesion molecule and ultrastructural changes during alginate and pellet culture has not been described. Hence, the present study was conducted comparing MSCs cultured in pellet and alginate beads with monolayer culture. qPCR was performed to assess the expression of chondrogenic, hypertrophic, and cell adhesion molecule genes, whereas transmission electron microscopy (TEM) was used to assess the ultrastructural changes. In addition, immunocytochemistry for Collagen type II and aggrecan and glycosaminoglycan (GAG) analysis were performed. Our results indicate that pellet and alginate bead cultures were necessary for chondrogenic differentiation of MSC. It also indicates that cultures using alginate bead demonstrated significantly higher (p < 0.05) chondrogenic but lower hypertrophic (p < 0.05) gene expressions as compared with pellet cultures. N-cadherin and N-CAM1 expression were up-regulated in second and third weeks of culture and were comparable between the alginate bead and pellet culture groups, respectively. TEM images demonstrated ultrastructural changes resembling cell death in pellet cultures. Our results indicate that using alginate beads, MSCs express higher chondrogenic but lower hypertrophic gene expression. Enhanced production of extracellular matrix and cell adhesion molecules was also observed in this group. These findings suggest that alginate bead culture may serve as a superior chondrogenic model, whereas pellet culture is more appropriate as a hypertrophic model of chondrogenesis.
  2. Fulltext Probable impact of age and hypoxia on proliferation and microRNA expression profile of bone marrow-derived human mesenchymal stem cells
    Mohd Ali N, Boo L, Yeap SK, Ky H, Satharasinghe DA, Liew WC, et al.
    PeerJ, 2016;4:e1536.
    PMID: 26788424 DOI: 10.7717/peerj.1536
    Decline in the therapeutic potential of bone marrow-derived mesenchymal stem cells (MSC) is often seen with older donors as compared to young. Although hypoxia is known as an approach to improve the therapeutic potential of MSC in term of cell proliferation and differentiation capacity, its effects on MSC from aged donors have not been well studied. To evaluate the influence of hypoxia on different age groups, MSC from young (<30 years) and aged (>60 years) donors were expanded under hypoxic (5% O2) and normal (20% O2) culture conditions. MSC from old donors exhibited a reduction in proliferation rate and differentiation potential together with the accumulation of senescence features compared to that of young donors. However, MSC cultured under hypoxic condition showed enhanced self-renewing and proliferation capacity in both age groups as compared to normal condition. Bioinformatic analysis of the gene ontology (GO) and KEGG pathway under hypoxic culture condition identified hypoxia-inducible miRNAs that were found to target transcriptional activity leading to enhanced cell proliferation, migration as well as decrease in growth arrest and apoptosis through the activation of multiple signaling pathways. Overall, differentially expressed miRNA provided additional information to describe the biological changes of young and aged MSCs expansion under hypoxic culture condition at the molecular level. Based on our findings, the therapeutic potential hierarchy of MSC according to donor's age group and culture conditions can be categorized in the following order: young (hypoxia) > young (normoxia) > old aged (hypoxia) > old aged (normoxia).
  3. Fulltext Development of a novel in vitro insulin resistance model in primary human tenocytes for diabetic tendinopathy research
    Tan HY, Tan SL, Teo SH, Roebuck MM, Frostick SP, Kamarul T
    PeerJ, 2020;8:e8740.
    PMID: 32587790 DOI: 10.7717/peerj.8740
    Background: Type 2 diabetes mellitus (T2DM) had been reported to be associated with tendinopathy. However, the underlying mechanisms of diabetic tendinopathy still remain largely to be discovered. The purpose of this study was to develop insulin resistance (IR) model on primary human tenocytes (hTeno) culture with tumour necrosis factor-alpha (TNF-α) treatment to study tenocytes homeostasis as an implication for diabetic tendinopathy.

    Methods: hTenowere isolated from human hamstring tendon. Presence of insulin receptor beta (INSR-β) on normal tendon tissues and the hTeno monolayer culture were analyzed by immunofluorescence staining. The presence of Glucose Transporter Type 1 (GLUT1) and Glucose Transporter Type 4 (GLUT4) on the hTeno monolayer culture were also analyzed by immunofluorescence staining. Primary hTeno were treated with 0.008, 0.08, 0.8 and 8.0 µM of TNF-α, with and without insulin supplement. Outcome measures include 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxy-d-glucose (2-NBDG) assay to determine the glucose uptake activity; colourimetric total collagen assay to quantify the total collagen expression levels; COL-I ELISA assay to measure the COL-I expression levels and real-time qPCR to analyze the mRNA gene expressions levels of Scleraxis (SCX), Mohawk (MKX), type I collagen (COL1A1), type III collagen (COL3A1), matrix metalloproteinases (MMP)-9 and MMP-13 in hTeno when treated with TNF-α. Apoptosis assay for hTeno induced with TNF-α was conducted using Annexin-V FITC flow cytometry analysis.

    Results: Immunofluorescence imaging showed the presence of INSR-β on the hTeno in the human Achilles tendon tissues and in the hTeno in monolayer culture. GLUT1 and GLUT4 were both positively expressed in the hTeno. TNF-α significantly reduced the insulin-mediated 2-NBDG uptake in all the tested concentrations, especially at 0.008 µM. Total collagen expression levels and COL-I expression levels in hTeno were also significantly reduced in hTeno treated with 0.008 µM of TNF-α. The SCX, MKX and COL1A1 mRNA expression levels were significantly downregulated in all TNF-α treated hTeno, whereas the COL3A1, MMP-9 and MMP-13 were significantly upregulated in the TNF-α treated cells. TNF-α progressively increased the apoptotic cells at 48 and 72 h.

    Conclusion: At 0.008 µM of TNF-α, an IR condition was induced in hTeno, supported with the significant reduction in glucose uptake, as well as significantly reduced total collagen, specifically COL-I expression levels, downregulation of candidate tenogenic markers genes (SCX and MKX), and upregulation of ECM catabolic genes (MMP-9 and MMP-13). Development of novel IR model in hTeno provides an insight on how tendon homeostasis could be affected and can be used as a tool for further discovering the effects on downstream molecular pathways, as the implication for diabetic tendinopathy.

  4. Fulltext Platelet-rich concentrate in serum free medium enhances osteogenic differentiation of bone marrow-derived human mesenchymal stromal cells
    Samuel S, Ahmad RE, Ramasamy TS, Karunanithi P, Naveen SV, Murali MR, et al.
    PeerJ, 2016;4:e2347.
    PMID: 27651984 DOI: 10.7717/peerj.2347
    Previous studies have shown that platelet concentrates used in conjunction with appropriate growth media enhance osteogenic differentiation of human mesenchymal stromal cells (hMSCs). However, their potential in inducing osteogenesis of hMSCs when cultured in serum free medium has not been explored. Furthermore, the resulting osteogenic molecular signatures of the hMSCs have not been compared to standard osteogenic medium. We studied the effect of infrequent supplementation (8-day interval) of 15% non-activated platelet-rich concentrate (PRC) in serum free medium on hMSCs proliferation and differentiation throughout a course of 24 days, and compared the effect with those cultured in a standard osteogenic medium (OM). Cell proliferation was analyzed by alamar blue assay. Gene expression of osteogenic markers (Runx2, Collagen1, Alkaline Phosphatase, Bone morphogenetic protein 2, Osteopontin, Osteocalcin, Osteonectin) were analyzed using Q-PCR. Immunocytochemical staining for osteocalcin, osteopontin and transcription factor Runx2 were done at 8, 16 and 24 days. Biochemical assays for the expression of ALP and osteocalcin were also performed at these time-points. Osteogenic differentiation was further confirmed qualitatively by Alizarin Red S staining that was quantified using cetylpyridinium chloride. Results showed that PRC supplemented in serum free medium enhanced hMSC proliferation, which peaked at day 16. The temporal pattern of gene expression of hMSCs under the influence of PRC was comparable to that of the osteogenic media, but at a greater extent at specific time points. Immunocytochemical staining revealed stronger staining for Runx2 in the PRC-treated group compared to OM, while the staining for Osteocalcin and Osteopontin were comparable in both groups. ALP activity and Osteocalcin/DNA level were higher in the PRC group. Cells in the PRC group had similar level of bone mineralization as those cultured in OM, as reflected by the intensity of Alizarin red stain. Collectively, these results demonstrate a great potential of PRC alone in inducing proliferation of hMSCs without any influence from other lineage-specific growth media. PRC alone has similar capacity to enhance hMSC osteogenic differentiation as a standard OM, without changing the temporal profile of the differentiation process. Thus, PRC could be used as a substitute medium to provide sufficient pool of pre-differentiated hMSCs for potential clinical application in bone regeneration.
  5. Fulltext Susceptibility of Human Oral Squamous Cell Carcinoma (OSCC) H103 and H376 cell lines to Retroviral OSKM mediated reprogramming
    Verusingam ND, Yeap SK, Ky H, Paterson IC, Khoo SP, Cheong SK, et al.
    PeerJ, 2017;5:e3174.
    PMID: 28417059 DOI: 10.7717/peerj.3174
    Although numbers of cancer cell lines have been shown to be successfully reprogrammed into induced pluripotent stem cells (iPSCs), reprogramming Oral Squamous Cell Carcinoma (OSCC) to pluripotency in relation to its cancer cell type and the expression pattern of pluripotent genes under later passage remain unexplored. In our study, we reprogrammed and characterised H103 and H376 oral squamous carcinoma cells using retroviral OSKM mediated method. Reprogrammed cells were characterized for their embryonic stem cells (ESCs) like morphology, pluripotent gene expression via quantitative real-time polymerase chain reaction (RT-qPCR), immunofluorescence staining, embryoid bodies (EB) formation and directed differentiation capacity. Reprogrammed H103 (Rep-H103) exhibited similar ESCs morphologies with flatten cells and clear borders on feeder layer. Reprogrammed H376 (Rep-H376) did not show ESCs morphologies but grow with a disorganized morphology. Critical pluripotency genes Oct4, Sox2 and Nanog were expressed higher in Rep-H103 against the parental counterpart from passage 5 to passage 10. As for Rep-H376, Nanog expression against its parental counterpart showed a significant decrease at passage 5 and although increased in passage 10, the level of expression was similar to the parental cells. Rep-H103 exhibited pluripotent signals (Oct4, Sox2, Nanog and Tra-1-60) and could form EB with the presence of three germ layers markers. Rep-H103 displayed differentiation capacity into adipocytes and osteocytes. The OSCC cell line H103 which was able to be reprogrammed into an iPSC like state showed high expression of Oct4, Sox2 and Nanog at late passage and may provide a potential iPSC model to study multi-stage oncogenesis in OSCC.
  6. Fulltext Factors Influencing the Successful Isolation and Expansion of Aging Human Mesenchymal Stem Cells
    Chong PP, Selvaratnam L, Abbas AA, Kamarul T
    Open Life Sci, 2018 Jan;13:279-284.
    PMID: 33817094 DOI: 10.1515/biol-2018-0034
    Most studies highlight mesenchymal stem cells (MSCs) extracted primarily from bone marrow (BM), very few report the use of peripheral blood (PB), often due to the associated low seeding density and difficulties with extraction techniques. As ageing populations are becoming more predominant globally, together with escalating demands for MSC transplantation and tissue regeneration, obtaining quality MSCs suitable for induced differentiation and biological therapies becomes increasingly important. In this study, BM and PB were obtained from elderly patients and extracted MSCs grown in vitro to determine their successful isolation and expansion. Patients' socio-demographic background and other medical information were obtained from medical records. Successful and failed cultures were correlated with key demographic and medical parameters. A total of 112 samples (BM or PB) were used for this study. Of these, 50 samples (44.6%) were successfully cultured according to standardised criteria with no signs of contamination. Our comparative analyses demonstrated no statistical correlation between successful MSC cultures and any of the six demographic or medical parameters examined, including sample quantity, age, sex, race, habits and underlying comorbidities of sample donors. In conclusion, the present study demonstrates that typical demographics and comorbidities do not influence successful MSC isolation and expansion in culture.
  7. Dual l-Carnosine/Aloe vera Nanophytosomes with Synergistically Enhanced Protective Effects against Methylglyoxal-Induced Angiogenesis Impairment
    Darvishi B, Dinarvand R, Mohammadpour H, Kamarul T, Sharifi AM
    Mol Pharm, 2021 09 06;18(9):3302-3325.
    PMID: 34297586 DOI: 10.1021/acs.molpharmaceut.1c00248
    Microvascular complications are among the major outcomes of patients with type II diabetes mellitus, which are the consequences of impaired physiological functioning of small blood vessels and angiogenic responses in these patients. Overproduction and accumulation of methylglyoxal (MGO), a highly reactive dicarbonyl byproduct of glycolysis pathway, has been acclaimed as the main inducer of impaired angiogenic responses and microvascular dysfunction in diabetic patients with uncontrolled hyperglycemia. Hence, an effective approach to overcome diabetes-associated microvascular complications is to neutralize the deleterious activity of enhanced the concentration of MGO in the body. Owing to the glycation inhibitory activity of Aloe vera whole extract, and capability of l-carnosine, an endogenous dipeptide, in attenuating MGO's destructive activity, we examined whether application of a combination of l-carnosine and A. vera could be an effective way of synergistically weakening this reactive dicarbonyl's impaired angiogenic effects. Additionally, overcoming the poor cellular uptake and internalization of l-carnosine and A. vera, a nanophytosomal formulation of the physical mixture of two compounds was also established. Although l-carnosine and A. vera at whole studied combination ratios could synergistically enhance viability of human umbilical vein endothelial cells (HUVECs) treated with MGO, the 25:1 w/w ratio was the most effective one among the others (27 ± 0.5% compared to 12 ± 0.3 to 18 ± 0.4%; F (4, 15) = 183.9, P < 0.0001). Developing dual nanophytosomes of l-carnosine/A. vera (25:1) combination ratio, we demonstrated superiority of the nanophytosomal formulation in protecting HUVECs against MGO-induced toxicity following a 24-72 h incubation period (17.3, 15.8, and 12.4% respectively). Moreover, 500 μg/mL concentration of dual l-carnosine/A. vera nanophytosomes exhibited a superior free radical scavenging potency (63 ± 4 RFU vs 83 ± 5 RFU; F (5, 12) = 54.81, P < 0.0001) and nitric oxide synthesizing capacity (26.11 ± 0.19 vs 5.1 ± 0.33; F (5, 12) = 2537, P < 0.0001) compared to their physical combination counterpart. Similarly, 500 μg/mL dual l-carnosine/A. vera nanophytosome-treated HUVECs demonstrated a superior tube formation capacity (15 ± 3 vs 2 ± 0.3; F (5, 12) = 30.87, P < 0.001), wound scratch healing capability (4.92 ± 0.3 vs 3.07 ± 0.3 mm/h; F (5, 12) = 39.21, P < 0.0001), and transwell migration (586 ± 32 vs 394 ± 18; F (5, 12) = 231.8, P < 0.001) and invasion (172 ± 9 vs 115 ± 5; F (5, 12) = 581.1, P < 0.0001) activities compared to the physical combination treated ones. Further confirming the proangiogenic activity of the dual l-carnosine/A. vera nanophytosomes, a significant shift toward expression of proangiogenic genes including HIF-1α, VEGFA, bFGF, KDR, and Ang II was reported in treated HUVECs. Overall, dual l-carnosine/A. vera nanophytosomes could be a potential candidate for attenuating type II DM-associated microvascular complications with an impaired angiogenesis background.
  8. Chondrocyte-alginate constructs with or without TGF-β1 produces superior extracellular matrix expression than monolayer cultures
    Ab-Rahim S, Selvaratnam L, Raghavendran HR, Kamarul T
    Mol Cell Biochem, 2013 Apr;376(1-2):11-20.
    PMID: 23238871 DOI: 10.1007/s11010-012-1543-0
    Tissue engineering approaches often require expansion of cell numbers in vitro to accelerate tissue regenerative processes. Although several studies have used this technique for therapeutic purposes, a major concern involving the use of isolated chondrocyte culture is the reduction of extracellular matrix (ECM) protein expressed due to the transfer of cells from the normal physiological milieu to the artificial 2D environment provided by the cell culture flasks. To overcome this issue, the use of alginate hydrogel beads as a substrate in chondrocyte cultures has been suggested. However, the resultant characteristics of cells embedded in this bead is elusive. To elucidate this, a study using chondrocytes isolated from rabbit knee articular cartilage expanded in vitro as monolayer and chondrocyte-alginate constructs was conducted. Immunohistochemical evaluation and ECM distribution was examined with or without transforming growth factor (TGF-β1) supplement to determine the ability of cells to express major chondrogenic proteins in these environments. Histological examination followed by transmission electron microscopy and scanning electron microscopy was performed to determine the morphology and the ultrastructural characteristics of these cells. Results demonstrated a significant increase in glycosaminoglycan/mg protein levels in chondrocyte cultures grown in alginate construct than in monolayer cultures. In addition, an abundance of ECM protein distribution surrounding chondrocytes cultured in alginate hydrogel was observed. In conclusion, the current study demonstrates that the use of alginate hydrogel beads in chondrocyte cultures with or without TGF-β1 supplement provided superior ECM expression than monolayer cultures.
  9. Finite element analysis of three commonly used external fixation devices for treating Type III pilon fractures
    Ramlee MH, Kadir MR, Murali MR, Kamarul T
    Med Eng Phys, 2014 Oct;36(10):1322-30.
    PMID: 25127377 DOI: 10.1016/j.medengphy.2014.05.015
    Pilon fractures are commonly caused by high energy trauma and can result in long-term immobilization of patients. The use of an external fixator i.e. the (1) Delta, (2) Mitkovic or (3) Unilateral frame for treating type III pilon fractures is generally recommended by many experts owing to the stability provided by these constructs. This allows this type of fracture to heal quickly whilst permitting early mobilization. However, the stability of one fixator over the other has not been previously demonstrated. This study was conducted to determine the biomechanical stability of these external fixators in type III pilon fractures using finite element modelling. Three-dimensional models of the tibia, fibula, talus, calcaneus, navicular, cuboid, three cuneiforms and five metatarsal bones were reconstructed from previously obtained CT datasets. Bones were assigned with isotropic material properties, while the cartilage was assigned as hyperelastic springs with Mooney-Rivlin properties. Axial loads of 350 N and 70 N were applied at the tibia to simulate the stance and the swing phase of a gait cycle. To prevent rigid body motion, the calcaneus and metatarsals were fixed distally in all degrees of freedom. The results indicate that the model with the Delta frame produced the lowest relative micromovement (0.03 mm) compared to the Mitkovic (0.05 mm) and Unilateral (0.42 mm) fixators during the stance phase. The highest stress concentrations were found at the pin of the Unilateral external fixator (509.2 MPa) compared to the Mitkovic (286.0 MPa) and the Delta (266.7 MPa) frames. In conclusion, the Delta external fixator was found to be the most stable external fixator for treating type III pilon fractures.
  10. Biomechanical evaluation of two commonly used external fixators in the treatment of open subtalar dislocation--a finite element analysis
    Ramlee MH, Kadir MR, Murali MR, Kamarul T
    Med Eng Phys, 2014 Oct;36(10):1358-66.
    PMID: 25092623 DOI: 10.1016/j.medengphy.2014.07.001
    Subtalar dislocation is a rare injury caused by high-energy trauma. Current treatment strategies include leg casts, internal fixation and external fixation. Among these, external fixators are the most commonly used as this method is believed to provide better stabilization. However, the biomechanical stability provided by these fixators has not been demonstrated. This biomechanical study compares two commonly used external fixators, i.e. Mitkovic and Delta. CT imaging data were used to reconstruct three-dimensional models of the tibia, fibula, talus, calcaneus, navicular, cuboid, three cuneiforms and five metatarsal bones. The 3D models of the bones and cartilages were then converted into four-noded linear tetrahedral elements, whilst the ligaments were modelled with linear spring elements. Bones and cartilage were idealized as homogeneous, isotropic and linear. To simulate loading during walking, axial loading (70 N during the swing and 350 N during the stance phase) was applied at the end of diaphyseal tibia. The results demonstrate that the Mitkovic fixator produced greater displacement (peak 3.0mm and 15.6mm) compared to the Delta fixator (peak 0.8mm and 3.9 mm), in both the swing and stance phase, respectively. This study demonstrates that the Delta external fixator provides superior stability over the Mitkovic fixator. The Delta fixator may be more effective in treating subtalar dislocation.
  11. Mechanical and functional assessment of the wrist affected by rheumatoid arthritis: A finite element analysis
    Bajuri MN, Kadir MR, Raman MM, Kamarul T
    Med Eng Phys, 2012 Nov;34(9):1294-302.
    PMID: 22277308 DOI: 10.1016/j.medengphy.2011.12.020
    Understanding the pathomechanics involved in rheumatoid arthritis (RA) of the wrist provides valuable information, which will invariably allow various therapeutic possibilities to be explored. The computational modelling of this disease permits the appropriate simulation to be conducted seamlessly. A study that underpins the fundamental concept that produces the biomechanical changes in a rheumatoid wrist was thus conducted through the use of finite element method. The RA model was constructed from computed tomography datasets, taking into account three major characteristics: synovial proliferation, cartilage destruction and ligamentous laxity. As control, a healthy wrist joint model was developed in parallel and compared. Cartilage was modelled based on the shape of the articulation while the ligaments were modelled with linear spring elements. A load-controlled analysis was performed simulating physiological hand grip loading conditions. The results demonstrated that the diseased model produced abnormal wrist extension and stress distribution as compared to the healthy wrist model. Due to the weakening of the ligaments, destruction of the cartilage and lower bone density, the altered biomechanical stresses were particularly evident at the radioscaphoid and capitolunate articulations which correlate to clinical findings. These results demonstrate the robust finding of the developed RA wrist model, which accurately predicted the pathological process.
  12. Biomechanical analysis of the wrist arthroplasty in rheumatoid arthritis: a finite element analysis
    Bajuri MN, Abdul Kadir MR, Murali MR, Kamarul T
    Med Biol Eng Comput, 2013 Feb;51(1-2):175-86.
    PMID: 23124814 DOI: 10.1007/s11517-012-0982-9
    The total replacement of wrists affected by rheumatoid arthritis (RA) has had mixed outcomes in terms of failure rates. This study was therefore conducted to analyse the biomechanics of wrist arthroplasty using recently reported implants that have shown encouraging results with the aim of providing some insights for the future development of wrist implants. A model of a healthy wrist was developed using computed tomography images from a healthy volunteer. An RA model was simulated based on all ten general characteristics of the disease. The ReMotion ™ total wrist system was then modelled to simulate total wrist arthroplasty (TWA). Finite element analysis was performed with loads simulating the static hand grip action. The results show that the RA model produced distorted patterns of stress distribution with tenfold higher contact pressure than the healthy model. For the TWA model, contact pressure was found to be approximately fivefold lower than the RA model. Compared to the healthy model, significant improvements were observed for the TWA model with minor variations in the stress distribution. In conclusion, the modelled TWA reduced contact pressure between bones but did not restore the stress distribution to the normal healthy condition.
  13. Number of pegs influence focal stress distributions and micromotion in glenoid implants: a finite element study
    Wahab AH, Kadir MR, Harun MN, Kamarul T, Syahrom A
    Med Biol Eng Comput, 2017 Mar;55(3):439-447.
    PMID: 27255451 DOI: 10.1007/s11517-016-1525-6
    The present study was conducted to compare the stability of four commercially available implants by investigating the focal stress distributions and relative micromotion using finite element analysis. Variations in the numbers of pegs between the implant designs were tested. A load of 750 N was applied at three different glenoid positions (SA: superior-anterior; SP: superior-posterior; C: central) to mimic off-center and central loadings during activities of daily living. Focal stress distributions and relative micromotion were measured using Marc Mentat software. The results demonstrated that by increasing the number of pegs from two to five, the total focal stress volumes exceeding 5 MPa, reflecting the stress critical volume (SCV) as the threshold for occurrence of cement microfractures, decreased from 8.41 to 5.21 % in the SA position and from 9.59 to 6.69 % in the SP position. However, in the C position, this change in peg number increased the SCV from 1.37 to 5.86 %. Meanwhile, micromotion appeared to remain within 19-25 µm irrespective of the number of pegs used. In conclusion, four-peg glenoid implants provide the best configuration because they had lower SCV values compared with lesser-peg implants, preserved more bone stock, and reduced PMMA cement usage compared with five-peg implants.
  14. Biomineralization, mechanical, antibacterial and biological investigation of larnite and rankinite bioceramics
    Venkatraman SK, Choudhary R, Krishnamurithy G, Raghavendran HRB, Murali MR, Kamarul T, et al.
    Mater Sci Eng C Mater Biol Appl, 2021 Jan;118:111466.
    PMID: 33255048 DOI: 10.1016/j.msec.2020.111466
    This work is aimed to develop a biocompatible, bactericidal and mechanically stable biomaterial to overcome the challenges associated with calcium phosphate bioceramics. The influence of chemical composition on synthesis temperature, bioactivity, antibacterial activity and mechanical stability of least explored calcium silicate bioceramics was studied. The current study also investigates the biomedical applications of rankinite (Ca3Si2O7) for the first time. Sol-gel combustion method was employed for their preparation using citric acid as a fuel. Differential thermal analysis indicated that the crystallization of larnite and rankinite occurred at 795 °C and 1000 °C respectively. The transformation of secondary phases into the desired product was confirmed by XRD and FT-IR. TEM micrographs showed the particle size of larnite in the range of 100-200 nm. The surface of the samples was entirely covered by the dominant apatite phase within one week of immersion. Moreover, the compressive strength of larnite and rankinite was found to be 143 MPa and 233 MPa even after 28 days of soaking in SBF. Both samples prevented the growth of clinical pathogens at a concentration of 2 mg/mL. Larnite and rankinite supported the adhesion, proliferation and osteogenic differentiation of hBMSCs. The variation in chemical composition was found to influence the properties of larnite and rankinite. The results observed in this work signify that these materials not only exhibit faster biomineralization ability, excellent cytocompatibility but also enhanced mechanical stability and antibacterial properties.
  15. In-vitro bioactivity, biocompatibility and dissolution studies of diopside prepared from biowaste by using sol-gel combustion method
    Choudhary R, Vecstaudza J, Krishnamurithy G, Raghavendran HRB, Murali MR, Kamarul T, et al.
    Mater Sci Eng C Mater Biol Appl, 2016 Nov 01;68:89-100.
    PMID: 27524000 DOI: 10.1016/j.msec.2016.04.110
    Diopside was synthesized from biowaste (Eggshell) by sol-gel combustion method at low calcination temperature and the influence of two different fuels (urea, l-alanine) on the phase formation temperature, physical and biological properties of the resultant diopside was studied. The synthesized materials were characterized by heating microscopy, FTIR, XRD, BET, SEM and EDAX techniques. BET analysis reveals particles were of submicron size with porosity in the nanometer range. Bone-like apatite deposition ability of diopside scaffolds was examined under static and circulation mode of SBF (Simulated Body Fluid). It was noticed that diopside has the capability to deposit HAP (hydroxyapatite) within the early stages of immersion. ICP-OES analysis indicates release of Ca, Mg, Si ions and removal of P ions from the SBF, but in different quantities from diopside scaffolds. Cytocompatability studies on human bone marrow stromal cells (hBMSCs) revealed good cellular attachment on the surface of diopside scaffolds and formation of extracellular matrix (ECM). This study suggests that the usage of eggshell biowaste as calcium source provides an effective substitute for synthetic starting materials to fabricate bioproducts for biomedical applications.
  16. Mechanical, antibacterial, and biocompatibility mechanism of PVD grown silver-tantalum-oxide-based nanostructured thin film on stainless steel 316L for surgical applications
    Alias R, Mahmoodian R, Genasan K, Vellasamy KM, Hamdi Abd Shukor M, Kamarul T
    Mater Sci Eng C Mater Biol Appl, 2020 Feb;107:110304.
    PMID: 31761210 DOI: 10.1016/j.msec.2019.110304
    Surgical site infection associated with surgical instruments has always been a factor in delaying post-operative recovery of patients. The evolution in surface modification of surgical instruments can be a potential choice to overcome the nosocomial infection mainly caused by bacterial populations such as Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. A study was, therefore, conducted characterising the morphology, hydrophobicity, adhesion strength, phase, Nano-hardness, surface chemistry, antimicrobial and biocompatibility of SS 316L steel deposited with a Nano-composite layer of Silver (Ag) and Tantalum oxide (Ta2O5) using physical vapour deposition magnetron sputtering. The adhesion strength of Ag/AgTa2O5 coating on SS 316L and treated at 250-850 °C of thermal treatment was evaluated using micro-scratch. The Ag/Ag-Ta2O5-400 °C was shown a 154% improvement in adhesion strength on SS 316L when compared with as-sputtered layer or Ag/Ag-Ta2O5-250, 550, 700 and 850 °C. The FESEM, XPS, and XRD indicated the segregation of Ag on the surface of SS 316L after the crystallization. Wettability and Nano-indentation tests demonstrated an increase in hydrophobicity (77.3 ± 0.3°) and Nano-hardness (1.12 ± 0.43 GPa) when compared with as-sputtered layer, after the 400 °C of thermal treatment. The antibacterial performance on Ag/Ag-Ta2O5-400 °C indicated a significant zone of inhibition to Staphylococcus aureus (A-axis: 16.33 ± 0.58 mm; B-axis: 25.67 ± 0.58 mm, p 
  17. Elastomeric biocomposite of silver-containing mesoporous bioactive glass and poly(1,8-octanediol citrate): Physiochemistry and in vitro antibacterial capacity in tissue engineering applications
    Pourshahrestani S, Zeimaran E, Kadri NA, Gargiulo N, Jindal HM, Hasikin K, et al.
    Mater Sci Eng C Mater Biol Appl, 2019 May;98:1022-1033.
    PMID: 30812986 DOI: 10.1016/j.msec.2019.01.022
    A novel series of silver-doped mesoporous bioactive glass/poly(1,8-octanediol citrate) (AgMBG/POC) elastomeric biocomposite scaffolds were successfully constructed by a salt-leaching technique for the first time and the effect of inclusion of different AgMBG contents (5, 10, and 20 wt%) on physicochemical and biological properties of pure POC elastomer was evaluated. Results indicated that AgMBG particles were uniformly dispersed in the POC matrix and increasing the AgMBG concentration into POC matrix up to 20 wt% enhanced thermal behaviour, mechanical properties and water uptake ability of the composite scaffolds compared to those from POC. The 20%AgMBG/POC additionally showed higher degradation rate in Tris(hydroxymethyl)-aminomethane-HCl (Tris-HCl) compared with pure POC and lost about 26% of its initial weight after soaking for 28 days. The AgMBG phase incorporation also significantly endowed the resulting composite scaffolds with efficient antibacterial properties against Escherichia coli and Staphylococcus aureus bacteria while preserving their favorable biocompatibility with soft tissue cells (i.e., human dermal fibroblast cells). Taken together, our results suggest that the synergistic effect of both AgMBG and POC make these newly designed AgMBG/POC composite scaffold an attractive candidate for soft tissue engineering applications.
  18. Fulltext A Preliminary Study of Human Amniotic Membrane as a Potential Chondrocyte Carrier
    Boo, L., Sofiah, S., Selvaratnam, L., Tai, C.C., Pingguan-Murphy, B., Kamarul, T.
    Malays Orthop J, 2009;3(2):16-23.
    MyJurnal
    Purpose:To investigate the feasibilty of using processed human amniotic membrane (HAM) to support the attachment and proliferation of chondrocytes in vitro which it turn can be utilised as a cell delivery vehicle in tissue engineering applications. Methods: Fresh HAM obtained from patients undergoing routine elective ceasarean sections was harvested., processed and dried using either freez drying (FD) or air drying (AD) methods prior to sterilisation by gamma irradiation. Isolated, processed and characterised rabbit autologous chondrolytes were seeded on processsed HAM and cultured for up to three weeks. Cell attachment and proliferation were examined qualitatively using inverted brightfield microcospy. Results: Processed HAM appeared to allow cell attachment when implanted with chrondocytes. Although cells seeded on AD and FD HAM did not appear to attach as strongly as those seeded on glycerol preserved intact human amniotic membrane, these cells to be proliferated in cell culture conditions. Conclusion: Prelimanary results show that processed HAM chondrocyte attachment and proliferation.
  19. Fulltext Normal anterior cruciate ligament laxity in the Malaysian population
    Kamarul T, Razif A, Elina R, Azura M, Chan KY
    Malays Orthop J, 2007;1(2):11-16.
    MyJurnal
    A study to determine average knee laxity in the Malaysian population and how it affects daily living was conducted at the University Malaya Medical Centre between January and April 2004. Fifty two male and 76 female subjects were recruited for this study, all of whom were healthy volunteers with no ambulatory problems. Side to side knee laxity testing was performed using a KT-1000 arthrometer. Significant differences in knee laxity were noted among different races and between sexes. For instance, overall, Chinese and female study participants had higher knee laxity: (left knee, 2.17 mm (SD=1.30) and right knee was 2.88 mm (SD= 1.51)). On average, the difference between knees was 0.70 ± 1.26 mm (less than 1 mm) which is a smaller variation than reported in previous studies which suggested 3 mm. Despite finding knee laxity ranging from 0 to 8mm, no correlations were found between Lysholm, IKDC and Tegner knee outcome scores and the degree of knee laxity. No other predictors such as height, weight and age correlated with levels of knee laxity. We therefore conclude that knee laxity is a common occurrence in the normal population and is therefore not suitable as a sole predictor of knee function and should not be used as the only criteria for surgical intervention.
    Study site: Orthopedic clinic, Universiti Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia
  20. Fulltext COVID-19 in Singapore and Malaysia: Rising to the Challenges of Orthopaedic Practice in an Evolving Pandemic
    Tay K, Kamarul T, Lok WY, Mansor M, Li X, Wong J, et al.
    Malays Orthop J, 2020 Jul;14(2).
    PMID: 32313613 DOI: 10.5704/MOJ.2007.001
    With the increasing number of COVID-19 cases and related deaths worldwide, we decided to share the development of this condition in Singapore and Malaysia. First few cases were diagnosed in the two countries at the end of January 2020, and the numbers have surged to thousands by end of March 2020. We will focus on strategies adopted by the government and also the Orthopaedic community of the two countries up till the beginning of April 2020. We hope that by sharing of relevant information and knowledge on how we are managing the COVID-19 condition, we can help other communities, and health care workers to more effectively overcome this pandemic.
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