Displaying publications 1 - 20 of 35 in total

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  1. Zinc: indications in brain disorders
    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. Fulltext Psychiatric aspects of the acquired immunodeficiency syndrome. A case report
    Maniam T, Abu Bakar AK
    Med J Malaysia, 1988 Jun;43(2):166-9.
    PMID: 3237133
  3. Fulltext Transcutaneous bilirubinometry in Malay, Chinese and Indian term neonates
    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.
  4. Fulltext Evaluation of Melaleuca cajuputi (Family: Myrtaceae) Essential Oil in Aerosol Spray Cans against Dengue Vectors in Low Cost Housing Flats
    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.
  5. Job satisfaction and perceived future roles of Malaysian dental therapists: findings from a national survey
    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.
  6. Fulltext Religious beliefs in relation to smoking: a cross-sectional study among muslim males in the month of Ramadan
    Abu Bakar A Majid, Lokman H Johari, Amal M Nasir, Anselm, S.T., Chan, W.H., Noraziah A Rahman, et al.
    Malaysian Journal of Public Health Medicine, 2002;2(2):32-35.
    MyJurnal
    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.
  7. Cyp2a5 Promoter-based Gene Reporter Assay: A Novel Design of Cell-based Bioassay for Toxicity Prediction
    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.
  8. Fulltext Machine Learning Predictions on Outpatient No-Show Appointments in a Malaysia Major Tertiary Hospital
    Ahmad Hamdan AF, Abu Bakar A
    Malays J Med Sci, 2023 Oct;30(5):169-180.
    PMID: 37928795 DOI: 10.21315/mjms2023.30.5.14
    INTRODUCTION: A no-show appointment occurs when a patient does not attend a previously booked appointment. This situation can cause other problems, such as discontinuity of patient treatments as well as a waste of both human and financial resources. One of the latest approaches to address this issue is predicting no-shows using machine learning techniques. This study aims to propose a predictive analytical approach for developing a patient no-show appointment model in Hospital Kuala Lumpur (HKL) using machine learning algorithms.

    METHODS: This study uses outpatient data from the HKL's Patient Management System (SPP) throughout 2019. The final data set has 246,943 appointment records with 13 attributes used for both descriptive and predictive analyses. The predictive analysis was carried out using seven machine learning algorithms, namely, logistic regression (LR), decision tree (DT), k-near neighbours (k-NN), Naïve Bayes (NB), random forest (RF), gradient boosting (GB) and multilayer perceptron (MLP).

    RESULTS: The descriptive analysis showed that the no-show rate was 28%, and attributes such as the month of the appointment and the gender of the patient seem to influence the possibility of a patient not showing up. Evaluation of the predictive model found that the GB model had the highest accuracy of 78%, F1 score of 0.76 and area under the curve (AUC) value of 0.65.

    CONCLUSION: The predictive model could be used to formulate intervention steps to reduce no-shows, improving patient care quality.

  9. Apoptosis induced by desmethyl-lasiodiplodin is associated with upregulation of apoptotic genes and downregulation of monocyte chemotactic protein-3
    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.
  10. Mitochondrial targeting of bilirubin regulatory enzymes: An adaptive response to oxidative stress
    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.
  11. Fulltext Pituitary apoplexy: a rare cause of middle cerebral artery infarction
    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.
  12. Synthesis and characterization of poly(p-phenylene vinylene)
    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.
  13. Raised leptin concentrations in feto-placental tissues from women with preeclampsia
    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.
  14. Fulltext Quantitating proteinuria using the urinary protein creatinine index
    Norella Kong CT, Chin JH, Izham Cheong IK, Abu Bakar A
    Med J Malaysia, 1988 Jun;43(2):134-7.
    PMID: 3237129
  15. Concurrent stroke and ST-elevation myocardial infarction: Is it a contraindication for intravenous tenecteplase?
    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. Fulltext Rare and Unique Case of Midline Anterior Arch of Atlas Non-formation Mimicking Jefferson Type 1 Fracture
    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.
  17. Fulltext Microbiological quality evaluation of fried rice sold at food premises in Kuantan City, Pahang
    Abu Bakar A, Abdul Rafa AA, Abdullah Sani A
    International Journal of Allied Health Sciences, 2018;2(1):285-291.
    MyJurnal
    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.
  18. Fulltext Outbreak detection model based on danger theory
    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.
  19. Investigating the Co-Movement and Asymmetric Relationships of Oil Prices on the Shipping Stock Returns: Evidence from Three Shipping-Flagged Companies from Germany, South Korea, and Taiwan
    Saputra J, Mokhtar K, Abu Bakar A, Ruslan SMM
    Big Data, 2024 Feb 13.
    PMID: 38354271 DOI: 10.1089/big.2023.0026
    In the last 2 years, there has been a significant upswing in oil prices, leading to a decline in economic activity and demand. This trend holds substantial implications for the global economy, particularly within the emerging business landscape. Among the influential risk factors impacting the returns of shipping stocks, none looms larger than the volatility in oil prices. Yet, only a limited number of studies have explored the complex relationship between oil price shocks and the dynamics of the liner shipping industry, with specific focus on uncertainty linkages and potential diversification strategies. This study aims to investigate the co-movements and asymmetric associations between oil prices (specifically, West Texas Intermediate and Brent) and the stock returns of three prominent shipping companies from Germany, South Korea, and Taiwan. The results unequivocally highlight the indispensable role of oil prices in shaping both short-term and long-term shipping stock returns. In addition, the research underscores the statistical significance of exchange rates and interest rates in influencing these returns, with their effects varying across different time horizons. Notably, shipping stock prices exhibit heightened sensitivity to positive movements in oil prices, while exchange rates and interest rates exert contrasting impacts, one being positive and the other negative. These findings collectively illuminate the profound influence of market sentiment regarding crucial economic indicators within the global shipping sector.
  20. Salmonella related mycotic aneurysm with psoas and paraortic abscess treated conservatively
    Abu Bakar A, Ngiu CS, Mohamad Said MS, Periyasamy P
    Ann Acad Med Singap, 2011 Oct;40(10):467-8.
    PMID: 22206056
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