Displaying publications 1 - 20 of 34 in total

  1. Al-Haddad A, Che Ab Aziz ZA
    Int J Biomater, 2016;2016:9753210.
    PMID: 27242904 DOI: 10.1155/2016/9753210
    Bioceramic-based root canal sealers are considered to be an advantageous technology in endodontics. The aim of this review was to consider laboratory experiments and clinical studies of these sealers. An extensive search of the endodontic literature was made to identify publications related to bioceramic-based root canal sealers. The outcome of laboratory and clinical studies on the biological and physical properties of bioceramic-based sealers along with comparative studies with other sealers was assessed. Several studies were evaluated covering different properties of bioceramic-based sealers including physical properties, biocompatibility, sealing ability, adhesion, solubility, and antibacterial efficacy. Bioceramic-based sealers were found to be biocompatible and comparable to other commercial sealers. The clinical outcomes associated with the use of bioceramic-based root canal sealers are not established in the literature.
  2. Mustafa S, Bahar A, Aziz ZA, Suratman S
    J Environ Manage, 2016 Jan 01;165:159-166.
    PMID: 26433356 DOI: 10.1016/j.jenvman.2015.09.026
    Analytical study of the influence of both the pumping well discharge rate and pumping time on contaminant transport and attenuation is significant for hydrological and environmental science applications. This article provides an analytical solution for investigating the influence of both pumping time and travelling time together for one-dimensional contaminant transport in riverbank filtration systems by using the Green's function approach. The basic aim of the model is to understand how the pumping time and pumping rate, which control the travelling time, can affect the contaminant concentration in riverbank filtration systems. Results of analytical solutions are compared with the results obtained using a MODFLOW numerical model. Graphically, it is found that both analytical and numerical solutions have almost the same behaviour. Additionally, the graphs indicate that any increase in the pumping rate or simulation pumping time should increase the contamination in groundwater. The results from the proposed analytical model are well matched with the data collected from a riverbank filtration site in France. After this validation, the model is then applied to the first pilot project of a riverbank filtration system conducted in Malaysia. Sensitivity analysis results highlight the importance of degradation rates of contaminants on groundwater quality, for which higher utilization rates lead to the faster consumption of pollutants.
  3. Al-Haddad A, Abu Kasim NH, Che Ab Aziz ZA
    Dent Mater J, 2015;34(4):516-21.
    PMID: 26235718 DOI: 10.4012/dmj.2015-049
    This study evaluated and compared the sealer thickness and interfacial adaptation of bioceramic sealers (Sankin Apatite III, MTA Fillapex(®), EndoSequence(®) BC) to root dentin against AH Plus(®) sealer. Sixty extracted single-root premolars were prepared and equally divided into four groups. Sealers were labeled with 0.1% Rhodamine B fluorescent dye. Roots were dissected along the transverse plane at 1 mm (apical), 3 mm (middle), and 6 mm (coronal) levels. Sealer-to-whole canal area ratio was evaluated. Percentage of gap-containing region to canal circumference was calculated using a confocal laser microscope. Sealer thickness was significantly higher at apical and middle levels than at coronal level. EndoSequence BC had the significantly highest thickness compared with MTA Fillapex and AH Plus. The coronal level had significantly less interfacial gaps compared with apical and middle levels. Bioceramic sealers showed more gaps compared with AH Plus, with no significant differences among them.
  4. Mustafa S, Bahar A, Aziz ZA, Darwish M
    J Contam Hydrol, 2020 Aug;233:103662.
    PMID: 32569923 DOI: 10.1016/j.jconhyd.2020.103662
    This article provides an analytical solute transport model to investigate the potential of groundwater contamination by polluted surface water in a two dimensional domain. The clogging of streambed which makes the aquifer partially penetrated by the stream, is considered in the model. The impacts of pumping process, hydraulic conductivity and clogging layer on the quality of water produced from nearby drinking water wells are evaluated. It is found that results are consistent with numerical simulation conducted by MODFLOW software. Moreover, the model is applied using data of contamination occurrence in Malaysia, where high contaminants concentrations are found close to streams. Results show that the pumping activities (rate and time period) are crucial factors when evaluating the risk of groundwater contamination from surface water. Additionally, this study illustrates that the increase in either hydraulic conductivity or leakance coefficient parameters due to the clogging layer will enlarge the area of contamination. The model is able to determine the suitable pumping rate and location of the well so that the contamination plume never reaches the extraction well, which is useful in constructing riverbank filtration sites.
  5. Ganasegeran K, Ch'ng ASH, Aziz ZA, Looi I
    Sci Rep, 2020 07 09;10(1):11353.
    PMID: 32647336 DOI: 10.1038/s41598-020-68335-1
    Stroke has emerged as a major public health concern in Malaysia. We aimed to determine the trends and temporal associations of real-time health information-seeking behaviors (HISB) and stroke incidences in Malaysia. We conducted a countrywide ecological correlation and time series study using novel internet multi-timeline data stream of 6,282 hit searches and conventional surveillance data of 14,396 stroke cases. We searched popular search terms related to stroke in Google Trends between January 2004 and March 2019. We explored trends by comparing average relative search volumes (RSVs) by month and weather through linear regression bootstrapping methods. Geographical variations between regions and states were determined through spatial analytics. Ecological correlation analysis between RSVs and stroke incidences was determined via Pearson's correlations. Forecasted model was yielded through exponential smoothing. HISB showed both cyclical and seasonal patterns. Average RSV was significantly higher during Northeast Monsoon when compared to Southwest Monsoon (P 
  6. Al-Haddad AY, Kutty MG, Che Ab Aziz ZA
    Int J Biomater, 2018;2018:1731857.
    PMID: 30154852 DOI: 10.1155/2018/1731857
    Objectives: To evaluate the push-out bond strength of experimental apatite calcium phosphate coated gutta-percha (HAGP) compared to different commercially available coated gutta-percha root obturation points.

    Methods: Extracted teeth were selected and instrumented using ProTaper rotary files. The canals were assigned into five equal groups and obturated using matching single cone technique as follows: EndoREZ cones and EndoREZ sealer, Bioceramic Endosequence gutta-percha (BCGP) with Endosequence BC sealer, Active GP with Endosequence BC sealer (ActiV GP), conventional GP with Endosequence BC sealer, and HAGP with Endosequence BC sealer. Each root was sectioned transversally at the thickness of 1±0.1 mm to obtain 5 sections (n=25 per group). The specimens were subjected to push-out test using a Universal Test Machine at a loading speed of 0.5 mm/ min. Failure modes after push-out test was examined under stereomicroscope and the push-out data were analyzed using ANOVA and the post hoc Dunnett T3 test (p = 0.05).

    Results: The highest mean bond strength was yielded by HAGP followed by BCGP, ActiV GP, conventional GP, and EndoREZ. There were significant differences between EndoREZ and all other groups (p<0.001). The prominent failure mode of HAGP was mixed mode, whereas EndoREZ exhibited adhesive failure mode. Conventional GP, ActiV GP, and BCGP showed cohesive failure mode.

    Conclusion: HAGP showed promising results to be used as root canal filling material in combination with bioceramic sealer.

  7. Mustafa S, Darwish M, Bahar A, Aziz ZA
    Ground Water, 2019 09;57(5):756-763.
    PMID: 30740693 DOI: 10.1111/gwat.12868
    Analytical studies for well design adjacent to river banks are the most significant practical task in cases involving the efficiency of riverbank filtration systems. In times when high pollution of river water is joined with increasing water demand, it is necessary to design pumping wells near the river that provide acceptable amounts of river water with minimum contaminant concentrations. This will guarantee the quality and safety of drinking water supplies. This article develops an analytical solution based on the Green's function approach to solve an inverse problem: based on the required level of contaminant concentration and planned pumping time period, the shortest distance to the riverbank that has the maximum percentage of river water is determined. This model is developed in a confined and homogenous aquifer that is partially penetrated by the stream due to the existence of clogging layers. Initially, the analytical results obtained at different pumping times, rates and with different values of initial concentration are checked numerically using the MODFLOW software. Generally, the distance results obtained from the proposed model are acceptable. Then, the model is validated by data related to two pumping wells located at the first riverbank filtration pilot project conducted in Malaysia.
  8. Mustafa S, Bahar A, Aziz ZA, Darwish M
    Environ Sci Pollut Res Int, 2022 Dec;29(58):87114-87131.
    PMID: 35802329 DOI: 10.1007/s11356-022-21402-8
    Modeling three-dimensional contaminant transport released from arbitrary shape source geometries is useful in hydrological and environmental sciences. This article produces several analytical solutions for three-dimensional contaminant transport in a homogeneous and isotropic aquifer by using Green's function with the groundwater flow which is assumed to be in three directions. The solutions are obtained for both finite depth aquifer and semi-infinite depth aquifer. Various types of sources are discussed: point, line, plane, or cuboid sources. The continuous and instantaneous sources are also investigated. A MATLAB coding is developed to calculate the numerical integrals which occur at the solutions. Some solutions are verified with the solutions obtained in the literature. This study confirms the effect of groundwater velocities in all directions on the degree and the directions of contaminant spreading. Additionally, the results highlight the significant effect of the geometrical shape of the contaminant sources on contaminant concentrations for instantaneous and continuous sources. In particular, the cuboid source and the horizontal rectangular source provide the highest concentrations. The analytical solutions developed in this article can be applied for a wide range of contaminant transport.
  9. Aziz ZA, Noordin NM, Wan Mohd WM, Kasim MA
    PLoS One, 2023;18(2):e0279882.
    PMID: 36763619 DOI: 10.1371/journal.pone.0279882
    Diagnosis and treatment of tuberculosis infection (TBI) are the core elements of tuberculosis elimination. Interferon gamma release assays have advantages over the tuberculin skin test, although their implementation in low-resource settings is challenging. The performance of a novel digital lateral flow assay QIAreach® QuantiFERON®-TB (QIAreach QFT) against the QuantiFERON®-TB Gold Plus (QFT-Plus) assay was evaluated in an intermediate incidence setting (Malaysia) according to the manufacturer's instructions. Individuals aged 4-82 years, who were candidates for TB infection screening for contact investigation were prospectively recruited. On 196 samples, the QIAreach-QFT showed a positive percent agreement (sensitivity) was 96.5% (CI 87.9-99.6%), a negative percent agreement (specificity) 94.2% (CI 88.4% to 97.6%) and an overall percentage of agreement was 94.9% (95% CI 90.6-97.6%) with a Cohen's κ of 0,88. Out of 196, 5.6% (11/196) samples gave an error result on QIAreach-QFT and 4.1% (8/196) samples gave indeterminate result on QFT-plus. The TTR for QIAreach QFT positive samples varied from 210-1200 seconds (20 min) and significantly correlated with IFN-γ level of QFT-Plus. QIAreach QFT could be considered an accurate and reliable point-of-need test to diagnose TB infection helping to achieve the WHO End TB programme goals even in decentralised settings where laboratory expertise and infrastructure may be limited.
  10. Moses LB, Abu Bakar MF, Mamat H, Aziz ZA
    PMID: 33603822 DOI: 10.1155/2021/8811236
    The present study was conducted to determine the cytotoxicity effect of Eurycoma longifolia (Jack.) leaf extracts and also its possible anticancer mechanism of action against breast cancer cell lines: non-hormone-dependent MDA-MB-231 and hormone-dependent MCF-7. The leaves of E. longifolia were processed into unfermented and fermented batches before drying using freeze and microwave-oven drying techniques. Obtained extracts were tested for cytotoxicity effect using MTT assay and phenolic determination using HPLC-DAD technique. The most toxic sample was analyzed for its apoptotic cell quantification, cell cycle distribution, and the expression of caspases and apoptotic protein using flow cytometry technique. Fragmentation of DNA was tested using an agarose gel electrophoresis system. The results determined that the unfermented freeze-dried leaf extract was the most toxic towards MDA-MB-231 and MCF-7 cells, in a dose-dependent manner. This extract contains the highest phenolics of gallic acid, chlorogenic acid, ECG, and EGCG. The DNA fragmentation was observed in both cell lines, where cell cycle was arrested at the G2/M phase in MCF-7 cells and S phase in MDA-MB-231 cells. The number of apoptotic cells for MDA-MB-231 was increased when the treatment was prolonged from 24 h to 48 h but slightly decreased at 72 h, whereas apoptosis in MCF-7 cells occurred in a time-dependent manner. There were significant activities of cytochrome c, caspase-3, Bax, and Bcl-2 apoptotic protein in MDA-MB-231 cells, whereas MCF-7 cells showed significant activities for caspase-8, cytochrome c, Bax, p53, and Bcl-2 apoptotic protein. These results indicate the ability of unfermented freeze-dried leaf extract of E. longifolia to induce apoptosis cell death on MDA-MB-231 and MCF-7, as well as real evidence on sample preparation effect towards its cytotoxicity level.
  11. Abu Kasim NH, Govindasamy V, Gnanasegaran N, Musa S, Pradeep PJ, Srijaya TC, et al.
    J Tissue Eng Regen Med, 2015 Dec;9(12):E252-66.
    PMID: 23229816 DOI: 10.1002/term.1663
    The discovery of mesenchymal stem cells (MSCs) from a myriad of tissues has triggered the initiative of establishing tailor-made stem cells for disease-specific therapy. Nevertheless, lack of understanding on the inherent differential propensities of these cells may restrict their clinical outcome. Therefore, a comprehensive study was done to compare the proliferation, differentiation, expression of cell surface markers and gene profiling of stem cells isolated from different sources, viz. bone marrow, Wharton's jelly, adipose tissue and dental pulp. We found that although all MSCs were phenotypically similar to each other, Wharton's jelly (WJ) MSCs and dental pulp stem cells (DPSCs) were highly proliferative as compared to bone marrow (BM) MSCs and adipose tissue (AD) MSCs. Moreover, indistinguishable cell surface characteristics and differentiation capacity were confirmed to be similar among all cell types. Based on gene expression profiling, we postulate that BM-MSCs constitutively expressed genes related to inflammation and immunodulation, whereas genes implicated in tissue development were highly expressed in AD-MSCs. Furthermore, the transcriptome profiling of WJ-MSCs and DPSCs revealed an inherent bias towards the neuro-ectoderm lineage. Based on our findings, we believe that there is no unique master mesenchymal stem cell that is appropriate to treat all target diseases. More precisely, MSCs from different sources exhibit distinct and unique gene expression signatures that make them competent to give rise to specific lineages rather than others. Therefore, stem cells should be subjected to rigorous characterization and utmost vigilance needs to be adopted in order to choose the best cellular source for a particular disease.
  12. Aziz ZA, Lee YY, Ngah BA, Sidek NN, Looi I, Hanip MR, et al.
    J Stroke Cerebrovasc Dis, 2015 Dec;24(12):2701-9.
    PMID: 26338106 DOI: 10.1016/j.jstrokecerebrovasdis.2015.07.025
    Stroke remains a major health burden worldwide. The incidence and prevalence rates of stroke are decreasing in developed countries, an opposite trend is taking place in the Asia Pacific, where an increasing number of patients are being diagnosed with acute stroke. The results of the present study on acute stroke in multi-ethnic Malaysia will significantly contribute to the global stroke epidemiological data. We aimed to present epidemiological data of stroke including incidence and prevalence rates as well as associated risk factors from a prospective nationwide hospital-based registry from 2010 to 2014.
  13. Aziz ZA, Lee YY, Sidek NN, Ngah BA, Looi I, Hanip MR, et al.
    Neurol Res, 2016 May;38(5):406-13.
    PMID: 27142804 DOI: 10.1080/01616412.2016.1178948
    Gender as an independent predictor in stroke has been well documented. However, data on gender differences among first-ever ischemic stroke in developing country are limited. We aim to describe gender effects on clinical characteristics, thrombolysis treatment received, and outcomes of patients with first-ever ischemic stroke.
  14. Chen XW, Shafei MN, Aziz ZA, Sidek NN, Musa KI
    J Neurol Sci, 2019 Jun 15;401:130-135.
    PMID: 31000206 DOI: 10.1016/j.jns.2019.04.015
    BACKGROUND: Stroke outcomes could be a quality indicator across the continuum of care and inform stroke management policymaking. However, this topic has rarely to date been studied directly.

    AIMS: We sought to investigate recent trends in stroke outcomes at hospital discharge among first-ever stroke patients.

    METHODS: This was an analysis of data from the Malaysia National Stroke Registry. Patients aged 18 years or older documented as having a first episode of stroke in the registry were recruited. Subsequently, the comparison of proportions for overall and sex-specific stroke outcomes between years (from 2009 to 2017) was conducted. The primary outcome was modified Rankin Scale score, which was assessed at hospital discharge, and each patient was categorized as follows: 1) functional independence, 2) functional dependence, or 3) death for analysis.

    RESULTS: This study included 9361 first-ever stroke patients. Approximately 36.2% (3369) were discharged in an independence state, 53.1% (4945) experienced functional dependence, and 10.8% (1006) patients died at the time of hospital discharge. The percentage of patients who were discharged independently increased from 23.3% in 2009 to 46.5% in 2017, while that of patients discharged in a disabled state fell from 56.0% in 2009 to 45.6% in 2017. The percentage of death at discharge was reduced from 20.7% in 2009 to 7.8% in 2017. These findings suggest that the proportions of stroke outcomes at hospital discharge have changed significantly over time (p 

  15. Al-Haddad AY, Kutty MG, Abu Kasim NH, Che Ab Aziz ZA
    J Dent Sci, 2017 Dec;12(4):340-346.
    PMID: 30895073 DOI: 10.1016/j.jds.2017.03.008
    Background/purpose: Intraradicular moisture is not standardized and alters the sealing properties and adhesion of root sealers. The aim of this work was to evaluate the effect of different moisture on the constitution of bioceramic sealers.

    Materials and methods: The sealers were evaluated before mixing, and after setting using X-ray diffraction (XRD), Energy Dispersive Analysis (EDX) and Scanning Electron Microscope (SEM) techniques. Twenty four extracted teeth were prepared and assigned to four groups according to the moisture conditions: (1) dry: using ethanol as final irrigation, (2) normal: using paper points until the last one appeared dry, (3) moist: using a Luer adapter for 5 s followed by 1 paper point, and (4) wet: the canals remained totally flooded. The roots were filled with MTA Fillapex® and Endosequence® BC and kept in phosphate buffer solution at 37 °C for 10 days. Each root was sectioned transversally and longitudinally. The sealers harvested from longitudinal sections were analysed using XRD. Whilst the transverse sections were analysed using SEM/EDX.

    Results: The XRD analysis showed MTA Fillapex composed of Bismuth trioxide, calcium silicate and tricalcium aluminate. The intensity of peaks in the wet condition was reduced. Endosequence BC contained mainly calcium silicate, calcium silicate hydrate, zirconia and calcium hydroxide. The wet condition showed a small increase in hydrated calcium silicate. The EDX analysis showed changes in the elemental concentrations with different moisture conditions. The surface morphology differed with different moisture conditions.

    Conclusion: Tested sealers have different constitution that not affected by the degree of moisture. However, it changed their relative quantity.

  16. Inoue Y, Kaneko S, Hsieh PF, Meshram C, Lee SA, Aziz ZA, et al.
    Epilepsia, 2019 03;60 Suppl 1:60-67.
    PMID: 30869167 DOI: 10.1111/epi.14645
    This post hoc analysis assessed the long-term safety, tolerability, and efficacy of perampanel in Asian patients with refractory focal seizures; an additional analysis assessed the effect of perampanel on focal impaired awareness seizures (FIAS) with focal to bilateral tonic-clonic (FBTC) seizures. In this subanalysis, data from Asian patients ≥12 years of age who had focal seizures with FBTC seizures despite taking one to 3 concomitant antiepileptic drugs at baseline, and who had entered either the long-term extension phase of 3 phase-3 perampanel trials (study 307) or the 10-week extension phase of study 335, were analyzed for the effect of perampanel on duration of exposure, safety, and seizure outcomes. Of 874 Asian patients included in the analysis, 205 had previously received placebo during the double-blind phase-3 trials and 669 had previously received perampanel 2-12 mg/day; 313 had FIAS with FBTC seizures at core study baseline. The median duration of exposure to perampanel was 385.0 days, and the retention rate at one year was 62.6%. Overall, during the first 52 weeks of perampanel treatment, 777 patients (88.9%) had treatment-emergent adverse events (TEAEs), most of which were mild to moderate in severity. The most frequent TEAEs were dizziness (47.1%), somnolence (22.3%), and nasopharyngitis (17.4%). During the first 52 weeks of perampanel treatment, median percent change in seizure frequency per 28 days from pre-perampanel baseline for all focal seizures was -28.1%, and -51.7% for FIAS with FBTC seizures. The 50% responder rate relative to pre-perampanel baseline for all focal seizures was 33.8%, and 51.1% for FIAS with FBTC seizures. Long-term treatment with perampanel in Asian patients had safety, tolerability, and efficacy similar to that of the global population in the phase-3 trials and extension study 307. The safety profile and response rate suggest benefit for an Asian population of patients with refractory epilepsy.
  17. Yap WY, Che Ab Aziz ZA, Azami NH, Al-Haddad AY, Khan AA
    Med Princ Pract, 2017;26(5):464-469.
    PMID: 28934753 DOI: 10.1159/000481623
    OBJECTIVE: To evaluate the push-out bond strength and failure modes of different sealers/obturation systems to intraradicular dentin at 2 weeks and 3 months after obturation compared to AH Plus®/gutta-percha.

    MATERIALS AND METHODS: A total of 180 root slices from 60 single-canal anterior teeth were prepared and assigned to 5 experimental groups (n = 36 in each group), designated as G1 (AH Plus®/gutta-percha), G2 (TotalFill BC™ sealer/BC-coated gutta-percha), G3 (TotalFill BC™ sealer/gutta-percha), G4 (EndoREZ® sealer/EndoREZ®-coated gutta-percha), and G5 (EndoREZ® sealer/gutta-percha). Push-out bond strengths of 18 root slices in each group were assessed at 2 weeks and the other 18 at 3 months after obturation using a universal testing machine. Data were analyzed using repeated measures ANOVA. An independent t test was used to compare the mean push-out bond strength for each group at 2 weeks and 3 months after obturation.

    RESULTS: The mean push-out bond strengths of G4 and G5 were significantly lower than those of G1, G2, and G3 (p < 0.05) at both 2 weeks (G1: 1.46 ± 0.29 MPa, G2: 1.74 ± 0.43 MPa, G3: 1.74 ± 0.43 MPa, G4: 0.66 ± 0.31 MPa, G5: 0.74 ± 0.47 MPa) and 3 months after obturation (G1: 1.70 ± 1.05 MPa, G2: 3.69 ± 1.20 MPa, G3: 2.84 ± 0.83 MPa, G4: 0.14 ± 0.05 MPa, G5: 0.24 ± 0.10 MPa). The mean push-out bond strengths of G2 (3.69 ± 1.20 MPa) and G3 (2.84 ± 0.83 MPa) were higher at 3 months compared to 2 weeks after obturation (G2: 1.74 ± 0.43 MPa, G3: 1.33 ± 0.29 MPa).

    CONCLUSION: The TotalFill BC™ obturation system (G2) and the TotalFill BC™ sealer/gutta-percha (G3) showed comparable bond strength to AH Plus®. Their bond strength increased over time, whereas the EndoREZ® obturation system (G4) and EndoREZ sealer (G5) had low push-out bond strength which decreased over time.

  18. Govindasamy V, Abdullah AN, Ronald VS, Musa S, Ab Aziz ZA, Zain RB, et al.
    J Endod, 2010 Sep;36(9):1504-15.
    PMID: 20728718 DOI: 10.1016/j.joen.2010.05.006
    Lately, several new stem cell sources and their effective isolation have been reported that claim to have potential for therapeutic applications. However, it is not yet clear which type of stem cell sources are most potent and best for targeted therapy. Lack of understanding of nature of these cells and their lineage-specific propensity might hinder their full potential. Therefore, understanding the gene expression profile that indicates their lineage-specific proclivity is fundamental to the development of successful cell-based therapies.
  19. Elhefnawy ME, Sheikh Ghadzi SM, Albitar O, Tangiisuran B, Zainal H, Looi I, et al.
    Front Neurol, 2023;14:1118711.
    PMID: 37188311 DOI: 10.3389/fneur.2023.1118711
    BACKGROUND: There are established correlations between risk factors and ischemic stroke (IS) recurrence; however, does the hazard of recurrent IS change over time? What is the predicted baseline hazard of recurrent IS if there is no influence of variable predictors? This study aimed to quantify the hazard of recurrent IS when the variable predictors were set to zero and quantify the secondary prevention influence on the hazard of recurrent ischemic stroke.

    METHODS: In the population cohort involved in this study, data were extracted from 7,697 patients with a history of first IS attack registered with the National Neurology Registry of Malaysia from 2009 to 2016. A time-to-recurrent IS model was developed using NONMEM version 7.5. Three baseline hazard models were fitted into the data. The best model was selected using maximum likelihood estimation, clinical plausibility, and visual predictive checks.

    RESULTS: Within the maximum 7.37 years of follow-up, 333 (4.32%) patients had at least one incident of recurrent IS. The data were well described by the Gompertz hazard model. Within the first 6 months after the index IS, the hazard of recurrent IS was predicted to be 0.238, and 6 months after the index attack, it reduced to 0.001. The presence of typical risk factors such as hyperlipidemia [HR, 2.22 (95%CI: 1.81-2.72)], hypertension [HR, 2.03 (95%CI: 1.52-2.71)], and ischemic heart disease [HR, 2.10 (95%CI: 1.64-2.69)] accelerated the hazard of recurrent IS, but receiving antiplatelets (APLTs) upon stroke decreased this hazard [HR, 0.59 (95%CI: 0.79-0.44)].

    CONCLUSION: The hazard of recurrent IS magnitude differs during different time intervals based on the concomitant risk factors and secondary prevention.

  20. Govindasamy V, Ronald VS, Abdullah AN, Nathan KR, Ab Aziz ZA, Abdullah M, et al.
    J Dent Res, 2011 May;90(5):646-52.
    PMID: 21335539 DOI: 10.1177/0022034510396879
    The post-natal dental pulp tissue contains a population of multipotent mesenchymal progenitor cells known as dental pulp stromal/stem cells (DPSCs), with high proliferative potential for self-renewal. In this investigation, we explored the potential of DPSCs to differentiate into pancreatic cell lineage resembling islet-like cell aggregates (ICAs). We isolated, propagated, and characterized DPSCs and demonstrated that these could be differentiated into adipogenic, chondrogenic, and osteogenic lineage upon exposure to an appropriate cocktail of differentiating agents. Using a three-step protocol reported previously by our group, we succeeded in obtaining ICAs from DPSCs. The identity of ICAs was confirmed as islets by dithiozone-positive staining, as well as by expression of C-peptide, Pdx-1, Pax4, Pax6, Ngn3, and Isl-1. There were several-fold up-regulations of these transcription factors proportional to days of differentiation as compared with undifferentiated DPSCs. Day 10 ICAs released insulin and C-peptide in a glucose-dependent manner, exhibiting in vitro functionality. Our results demonstrated for the first time that DPSCs could be differentiated into pancreatic cell lineage and offer an unconventional and non-controversial source of human tissue that could be used for autologous stem cell therapy in diabetes.
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links