Displaying publications 1 - 20 of 29 in total

  1. Prakash A, Bharti K, Majeed AB
    Fundam Clin Pharmacol, 2015 Apr;29(2):131-49.
    PMID: 25659970 DOI: 10.1111/fcp.12110
    Zinc is the authoritative metal which is present in our body, and reactive zinc metal is crucial for neuronal signaling and is largely distributed within presynaptic vesicles. Zinc also plays an important role in synaptic function. At cellular level, zinc is a modulator of synaptic activity and neuronal plasticity in both development and adulthood. Different importers and transporters are involved in zinc homeostasis. ZnT-3 is a main transporter involved in zinc homeostasis in the brain. It has been found that alterations in brain zinc status have been implicated in a wide range of neurological disorders including impaired brain development and many neurodegenerative disorders such as Alzheimer's disease, and mood disorders including depression, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, and prion disease. Furthermore, zinc has also been implicated in neuronal damage associated with traumatic brain injury, stroke, and seizure. Understanding the mechanisms that control brain zinc homeostasis is thus critical to the development of preventive and treatment strategies for these and other neurological disorders.
  2. Boo NY, Abu Bakar A
    Med J Malaysia, 1984 Mar;39(1):35-7.
    PMID: 6513837
    The transcutaneous (Tc) bilirubinometer was evaluated in 105 jaundiced neonates, comprising 38 Malays, 37 Chinese and 30 Indians, who had not been treated with phototherapy or exchange transfusion. Tc bilirubin index and serum bilirubin concentration correlated at statistically significant levels in all the three racial groups. Unlike the Chinese and Malay babies, the action levels, using Tc bilirubin index, in the Indian babies are not reliable due to the wide variation of skin pigmentation. Neonatal jaundice is conventionally monitored by estimation of serum bilirubin level. This involves blood sampling. The transcutaneous (Tc) bilirubinometer, however, is non-invasive, small and portable. In this study, the use of the Tc bilirubinometer in the management of neonatal jaundice' in the three racial groups was evaluated.
  3. Abu Bakar A, Sulaiman S, Omar B, Mat Ali R
    J Arthropod Borne Dis, 2012;6(1):28-35.
    PMID: 23293776
    Melaleuca cajuputi essential oil in aerosol spray was evaluated against the dengue vectors Aedes aegypti and Ae. albopictus at low cost housing flats in Section 10, Setapak, Kuala Lumpur, Malaysia.
  4. Abu Bakar A, Mohd Nor NA, Ab-Murat N, Jaafar N
    Int J Dent Hyg, 2015 Aug;13(3):199-205.
    PMID: 25040653 DOI: 10.1111/idh.12095
    OBJECTIVE: To assess Malaysian dental therapists' perceptions of their job satisfaction and future roles.
    METHODS: A nationwide postal survey involving all Malaysian dental therapists who met the inclusion criteria (n = 1726).
    RESULTS: The response rate was 76.8%. All respondents were females; mean age 35.4 years (SD = 8.4). Majority were married (85.5%) and more than one-half had a working experience of <10 years (56.1%). Majority worked in community dental service (94.3%) and in urban areas (61.7%). Overall, they were highly satisfied with most aspects of their career. However, they were least satisfied with administrative workload (58.1%), career advancement opportunities (51.9%) and remuneration package; specifically income (45.2%), allowances (45.2%) and non-commensurate between pay and performance (44.0%). Majority perceived their role as very important in routine clinical tasks such as examination and diagnosis, preventive treatment, extraction of deciduous teeth and oral health promotion. However, fewer than one-half consider complex treatment such as placement of preformed crowns on deciduous teeth (37.1%) and extraction of permanent teeth (37.2%) as very important tasks.
    CONCLUSION: Majority expressed high career satisfaction with most aspects of their employment but expressed low satisfaction in remuneration, lack of career advancement opportunities and administrative tasks. We conclude that most Malaysian dental therapists have positive perceptions of their current roles but do not favour wider expansion of their roles. These findings imply that there was a need to develop a more attractive career pathway for therapists to ensure sustainability of effective primary oral healthcare delivery system for Malaysia's children.
  5. Abu Bakar A Majid, Lokman H Johari, Amal M Nasir, Anselm, S.T., Chan, W.H., Noraziah A Rahman, et al.
    A cross—sectional study conducted in the fasting month of Ramadan targeting muslim males assessed their religious beliefs in relation to smoking and their intentions t0 quit smoking in Ramadan. It was found that there law; is a strong association between their perceptions on the religious ruling of smoking as haram (prohibited) in relation to their smoking status. Among the non smokers and ex smokers, 87.8% and 73.6% respectively accept the ruling on smoking as prohibitea'(haram), while only 31.6% of smokers accept smoking as prohibited. Among the smokers, 97.7% smoke a lesser number of cigarettes during Ramadan, while 96.7% of them felt that it is easier to quit during the fasting month. The findings suggest that the religious department needs to provide more information and education to the Muslim population as to the reasons of the ruling on smoking as haram(prohibited) on religious grounds . It was also found that the majority felt it is easier to quit during quit smoking programmes can be emphasized and carried out on a bigger scale during fasting months in the future.
  6. Abu-Bakar A, Hu H, Lang MA
    Basic Clin Pharmacol Toxicol, 2018 Sep;123 Suppl 5:72-80.
    PMID: 29788535 DOI: 10.1111/bcpt.13046
    The murine cytochrome P450 2a5 (Cyp2a5) gene is regulated by complex interactions of various stress-activated transcription factors (TFs). Elevated Cyp2a5 transcription under chemical-induced stress conditions is achieved by interplay between the various TFs - including as aryl hydrocarbon receptor (AhR) and nuclear factor (erythroid-derived 2)-like 2 wild-type (Nrf2) - at the 'stress-responding' cluster of response elements on the Cyp2a5 promoter, as well as through mRNA stabilization mediated by interaction of the stress-activated heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) with the 3'-UTR of the CYP2A5 mRNA. We designed a unique toxicity pathway-based reporter assay to include regulatory regions from both the 5' and the 3' untranslated regions of Cyp2a5 in a luciferase reporter plasmid to reflect in vivo responses to chemical insult. Human breast cancer MCF-7 cells were stably transfected with pGL4.38-Cyp2a5_Wt3k (wild-type) or mutant - pGL4.38-Cyp2a5_StREMut and pGL4.38-Cyp2a5_XREMut - reporter gene to monitor chemical-induced cellular response mediated by AhR and Nrf2 signalling. The recombinant cells were treated with representative of AhR agonist, polycyclic aromatic hydrocarbons, brominated flame retardant, fluorosurfactant, aromatic organic compound and metal, to determine the sensitivity of the Cyp2a5 promoter-based gene reporter assays to chemical insults by measuring the LC50 and EC50 of the respective chemicals. The three assays are sensitive to sublethal cellular responses of chemicals, which is an ideal feature for toxicity pathway-based bioassay for toxicity prediction. The wild-type reporter responded well to chemicals that activate crosstalk between the AhR and Nrf2, whilst the mutant reporters effectively gauge cellular response driven by either Nrf2/StRE or AhR/XRE signalling. Thus, the three gene reporter assays could be used tandemly to determine the predominant toxicity pathway of a given compound.
  7. Hazalin NA, Lim SM, Cole AL, Majeed AB, Ramasamy K
    Anticancer Drugs, 2013 Sep;24(8):852-61.
    PMID: 23764760 DOI: 10.1097/CAD.0b013e3283635a47
    There is growing interest in the discovery of bioactive metabolites from endophytes as an alternative source of therapeutics. Identification of their therapeutic targets is essential in understanding the underlying mechanisms and enhancing the resultant therapeutic effects. As such, bioactive compounds produced by endophytic fungi from plants at the National Park, Pahang, Malaysia, were investigated. Five known compounds were identified using LC-UV-MS-NMR and they include trichodermol, 7-epi-brefeldin A, (3R,4S)-4-hydroxymellein, desmethyl-lasiodiplodin and cytochalasin D. The present study went on to investigate the potential anticancer effects of these compounds and the corresponding molecular mechanisms of the lead compound against human breast adenocarcinoma, MCF-7. For the preliminary screening, the cytotoxicity and apoptotic effects of these compounds against MCF-7 were examined. The compounds were also tested against noncarcinogenic hepatocytes (WRL68). The differential cytotoxicity was then determined using the MTT assay. Desmethyl-lasiodiplodin was found to suppress the growth of MCF-7, yielding an inhibitory concentration (IC50) that was seven-fold lower than that of the normal cells. The cytotoxic effect of desmethyl-lasiodiplodin was accompanied by apoptosis. Subsequent analysis demonstrated increased expression levels of caspase 3, c-myc and p53. Further, desmethyl-lasiodiplodin resulted in inhibition of monocyte chemotactic protein (MCP)-3, a cytokine involved in cell survival and metastasis. Hence, this study proposed that desmethyl-lasiodiplodin inhibited growth and survival of MCF-7 through the induction of apoptosis. This anticancer effect is mediated, in part, by upregulation of apoptotic genes and downregulation of MCP-3. As desmethyl-lasiodiplodin elicited minimal impact against normal hepatocytes, our findings also imply its potential use as a specific apoptotic agent in breast cancer treatment.
  8. Muhsain SN, Lang MA, Abu-Bakar A
    Toxicol Appl Pharmacol, 2015 Jan 1;282(1):77-89.
    PMID: 25478736 DOI: 10.1016/j.taap.2014.11.010
    The intracellular level of bilirubin (BR), an endogenous antioxidant that is cytotoxic at high concentrations, is tightly controlled within the optimal therapeutic range. We have recently described a concerted intracellular BR regulation by two microsomal enzymes: heme oxygenase 1 (HMOX1), essential for BR production and cytochrome P450 2A5 (CYP2A5), a BR oxidase. Herein, we describe targeting of these enzymes to hepatic mitochondria during oxidative stress. The kinetics of microsomal and mitochondrial BR oxidation were compared. Treatment of DBA/2J mice with 200mgpyrazole/kg/day for 3days increased hepatic intracellular protein carbonyl content and induced nucleo-translocation of Nrf2. HMOX1 and CYP2A5 proteins and activities were elevated in microsomes and mitoplasts but not the UGT1A1, a catalyst of BR glucuronidation. A CYP2A5 antibody inhibited 75% of microsomal BR oxidation. The inhibition was absent in control mitoplasts but elevated to 50% after treatment. An adrenodoxin reductase antibody did not inhibit microsomal BR oxidation but inhibited 50% of mitochondrial BR oxidation. Ascorbic acid inhibited 5% and 22% of the reaction in control and treated microsomes, respectively. In control mitoplasts the inhibition was 100%, which was reduced to 50% after treatment. Bilirubin affinity to mitochondrial and microsomal CYP2A5 enzyme is equally high. Lastly, the treatment neither released cytochrome c into cytoplasm nor dissipated membrane potential, indicating the absence of mitochondrial membrane damage. Collectively, the observations suggest that BR regulatory enzymes are recruited to mitochondria during oxidative stress and BR oxidation by mitochondrial CYP2A5 is supported by mitochondrial mono-oxygenase system. The induced recruitment potentially confers membrane protection.
  9. Hassan R, Sharis Othman S, Ahmad Mukari SA, Abu Bakar A
    Med J Malaysia, 2013 Jun;68(3):264-6.
    PMID: 23749020 MyJurnal
    Pituitary apoplexy is a well-known complication of a pituitary adenoma. However, an ischaemic event caused by pituitary apoplexy is rare. We reported a case of pituitary apoplexy with middle cerebral artery infarction in a 44-year old man who presented with a sudden onset of altered sensorium. Vasospasm is the most likely underlying cause of the infarction in this case secondary to transdiaphragmatic rupture of the sella tumour into the subarachnoid space.
  10. Abd Rashid MY, Abu Bakar A, Mohd Asri MT, Iskandar SM
    Med J Malaysia, 2004 May;59 Suppl B:135-6.
    PMID: 15468855
    Poly (p-phenylene vinylene) (PPV) was synthesized from p-xylylene bis(tetrahydrothiophenium chloride) using the Wessling route and characterized by Fourier Transform Infra-Red (FTIR) and UV-visible (UV-VIS) spectroscopic techniques. The significance of thermal treatment along with evolution of precursor polymer to polymer PPV was also studied through these spectroscopic techniques. Thermally Stimulated Current (TSC) measurements indicated the presence of crystallization, sulphonium group which occurred through the evolution from precursor polymer to polymer PPV during thermal treatment.
  11. Singh HJ, Abu Bakar A, Che Romli A, Nila A
    Hypertens Pregnancy, 2005;24(2):191-9.
    PMID: 16036403
    The aim of this study was to estimate the levels of leptin in the amnion, chorion laeve, and placenta and to examine for any differences in leptin levels in these tissues from preeclamptic and normotensive pregnant women.
  12. Norella Kong CT, Chin JH, Izham Cheong IK, Abu Bakar A
    Med J Malaysia, 1988 Jun;43(2):134-7.
    PMID: 3237129
  13. Das S, Palaniandy K, Abu Bakar A, Idris Z, Abdullah JM
    Cureus, 2020 Feb 03;12(2):e6850.
    PMID: 32181085 DOI: 10.7759/cureus.6850
    Cervical spine injuries are rare occurrences in children, especially the congenital anomalies of the atlas vertebra. Any injury involving the craniovertebral junction such as Jefferson fracture, is a valid cause for alarm due to the complex nature of the craniovertebral junction and the morbidity associated with it. We report the case of a 10-year-old male, who had failure of fusion of anterior arch of atlas due to the failure of formation of the anterior midline synchondrosis, and this mimicked a Jefferson fracture. If it was not for the peculiar absence of any corresponding evidence to suggest spinal injury, we might have mistaken this extremely rare but benign anomaly for a Jefferson fracture and subjected the patient to needless surgical treatment. Hence, it is concluded that keen clinical acumen and clear understanding of the developmental anatomy of these patients may be necessary to adequately manage them.
  14. Mohamad Mohsin MF, Abu Bakar A, Hamdan AR
    Appl Soft Comput, 2014 Nov;24:612-622.
    PMID: 32362801 DOI: 10.1016/j.asoc.2014.08.030
    In outbreak detection, one of the key issues is the need to deal with the weakness of early outbreak signals because this causes the detection model to have has less capability in terms of robustness when unseen outbreak patterns vary from those in the trained model. As a result, an imbalance between high detection rate and low false alarm rate occurs. To solve this problem, this study proposes a novel outbreak detection model based on danger theory; a bio-inspired method that replicates how the human body fights pathogens. We propose a signal formalization approach based on cumulative sum and a cumulative mature antigen contact value to suit the outbreak characteristic and danger theory. Two outbreak diseases, dengue and SARS, are subjected to a danger theory algorithm; namely the dendritic cell algorithm. To evaluate the model, four measurement metrics are applied: detection rate, specificity, false alarm rate, and accuracy. From the experiment, the proposed model outperforms the other detection approaches and shows a significant improvement for both diseases outbreak detection. The findings reveal that the robustness of the proposed immune model increases when dealing with inconsistent outbreak signals. The model is able to detect new unknown outbreak patterns and can discriminate between outbreak and non-outbreak cases with a consistent high detection rate, high sensitivity, and lower false alarm rate even without a training phase.
  15. Wan Asyraf WZ, Elengoe S, Che Hassan HH, Abu Bakar A, Remli R
    Med J Malaysia, 2020 03;75(2):169-170.
    PMID: 32281601
    Acute ischemic stroke (AIS) and acute ST-elevation myocardial infarction (STEMI) are leading causes of mortality worldwide. Concurrent AIS presentation with STEMI is rare and potentially fatal. Most importantly to date many centres in Malaysia are still not aware on how to treat this condition. We report a case of AIS, which was treated with intravenous tenecteplase (TNK) according to ischemic stroke dosage and lead to improvement of neurological deficit.
  16. Abu Bakar A, Abdul Rafa AA, Abdullah Sani A
    Food contamination is a crucial health problem as it could result in food-borne illness. This research aimed to evaluate the microbiological quality of ready-to-eat (RTE) fried rice dishes sold at different type of food premises in Kuantan city, Pahang. Total Plate Count (TPC), Staphylococcus aureus, Bacillus cereus and Aeromonas spp. bacteria were used as microbiological contamination indicators. About 52 samples were collected stratified randomly from four types of food premises (restaurant, cafeteria, food stall and night market) where about 13 samples were respectively collected from each type of the food premises. The results showed that TPC had medium mean count (6.30x105±1.47x105 cfu/g), S. aureus and B. cereus had high mean counts (7.70x104±2.22x105 cfu/g and 3.85x105±1.67x106 cfu/g respectively), while Aeromonas spp. had medium mean count (7.13x104±2.42x105 cfu/g). The mean counts of TPC in the samples collected from cafeteria were highest compare to other food premises.
  17. Venketasubramanian N, Kumar R, Soertidewi L, Abu Bakar A, Laik C, Gan R
    BMJ Open, 2015 Nov 13;5(11):e009866.
    PMID: 26567259 DOI: 10.1136/bmjopen-2015-009866
    INTRODUCTION: NeuroAiD (MLC601, MLC901), a combination of natural products, has been shown to be safe and to aid neurological recovery after brain injuries. The NeuroAiD Safe Treatment (NeST) Registry aims to assess its use and safety in the real-world setting.

    METHODS AND ANALYSIS: The NeST Registry is designed as a product registry that would provide information on the use and safety of NeuroAiD in clinical practice. An online NeST Registry was set up to allow easy entry and retrieval of essential information including demographics, medical conditions, clinical assessments of neurological, functional and cognitive state, compliance, concomitant medications, and side effects, if any, among patients on NeuroAiD. Patients who are taking or have been prescribed NeuroAiD may be included. Participation is voluntary. Data collected are similar to information obtained during standard care and are prospectively entered by the participating physicians at baseline (before initialisation of NeuroAiD) and during subsequent visits. The primary outcome assessed is safety (ie, non-serious and serious adverse event), while compliance and neurological status over time are secondary outcomes. The in-person follow-up assessments are timed with clinical appointments. Anonymised data will be extracted and collectively analysed. Initial target sample size for the registry is 2000. Analysis will be performed after every 500 participants entered with completed follow-up information.

    ETHICS AND DISSEMINATION: Doctors who prescribe NeuroAiD will be introduced to the registry by local partners. The central coordinator of the registry will discuss the protocol and requirements for implementation with doctors who show interest. Currently, the registry has been approved by the Ethics Committees of Universiti Kebangsaan Malaysia (Malaysia) and National Brain Center (Indonesia). In addition, for other countries, Ethics Committee approval will be obtained in accordance with local requirements.


  18. Sakai N, Dayana E, Abu Bakar A, Yoneda M, Nik Sulaiman NM, Ali Mohd M
    Environ Monit Assess, 2016 Oct;188(10):592.
    PMID: 27679511
    Polychlorinated biphenyls (PCBs) were monitored in surface water collected in the Selangor River basin, Malaysia, to identify the occurrence, distribution, and dechlorination process as well as to assess the potential adverse effects to the Malaysian population. Ten PCB homologs (i.e., mono-CBs to deca-CBs) were quantitated by using gas chromatography-mass spectrometry (GC/MS). The total concentration of PCBs in the 10 sampling sites ranged from limit of detection to 7.67 ng L(-1). The higher chlorinated biphenyls (tetra-CBs to deca-CBs) were almost not detected in most of the sampling sites, whereas lower chlorinated biphenyls (mono-CBs, di-CBs, and tri-CBs) dominated more than 90 % of the 10 homologs in all the sampling sites. Therefore, the PCB load was estimated to be negligible during the sampling period because PCBs have an extremely long half-life. The PCBs, particularly higher chlorinated biphenyls, could be thoroughly dechlorinated to mono-CBs to tri-CBs by microbial decomposition in sediment or could still be accumulated in the sediment. The lower chlorinated biphenyls, however, could be resuspended or desorbed from the sediment because they have faster desorption rates and higher solubility, compared to the higher chlorinated biphenyls. The health risk for the Malaysia population by PCB intake that was estimated from the local fish consumption (7.2 ng kg(-1) bw day(-1)) and tap water consumption (1.5 × 10(-3)-3.1 × 10(-3) ng kg(-1) bw day(-1)) based on the detected PCB levels in the surface water was considered to be minimal. The hazard quotient based on the tolerable daily intake (20 ng kg(-1) bw day(-1)) was estimated at 0.36.
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