Displaying publications 1 - 20 of 68 in total

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  1. Fulltext Current state of the use of antibiotic prophylactics in cardiac surgery - correspondence
    Abdul-Rahman T, Omran MO, Ekerin O, Ghosh S, Awuah WA
    Int J Surg, 2023 Aug 01;109(8):2542-2543.
    PMID: 37158146 DOI: 10.1097/JS9.0000000000000445
  2. Antioxidant, anti-inflammatory and epigenetic potential of curcumin in Alzheimer's disease
    Abdul-Rahman T, Awuah WA, Mikhailova T, Kalmanovich J, Mehta A, Ng JC, et al.
    Biofactors, 2024 Jan 16.
    PMID: 38226733 DOI: 10.1002/biof.2039
    Alzheimer's disease (AD) constitutes a multifactorial neurodegenerative pathology characterized by cognitive deterioration, personality alterations, and behavioral shifts. The ongoing brain impairment process poses significant challenges for therapeutic interventions due to activating multiple neurotoxic pathways. Current pharmacological interventions have shown limited efficacy and are associated with significant side effects. Approaches focusing on the early interference with disease pathways, before activation of broad neurotoxic processes, could be promising to slow down symptomatic progression of the disease. Curcumin-an integral component of traditional medicine in numerous cultures worldwide-has garnered interest as a promising AD treatment. Current research indicates that curcumin may exhibit therapeutic potential in neurodegenerative pathologies, attributed to its potent anti-inflammatory and antioxidant properties. Additionally, curcumin and its derivatives have demonstrated an ability to modulate cellular pathways via epigenetic mechanisms. This article aims to raise awareness of the neuroprotective properties of curcuminoids that could provide therapeutic benefits in AD. The paper provides a comprehensive overview of the neuroprotective efficacy of curcumin against signaling pathways that could be involved in AD and summarizes recent evidence of the biological efficiency of curcumins in vivo.
  3. Letter: Addressing Neurosurgery Research and Data Access Gaps in War-Inflicted Nations
    Adebusoye FT, Awuah WA, Swaminathan N, Ghosh S, Wellington J, Abdul-Rahman T, et al.
    Neurosurgery, 2023 Aug 01;93(2):e30-e31.
    PMID: 37192472 DOI: 10.1227/neu.0000000000002527
  4. Fulltext A Food Frequency Questionnaire for Hemodialysis Patients in Bangladesh (BDHD-FFQ): Development and Validation
    Ahmed S, Rahman T, Ripon MSH, Rashid HU, Kashem T, Md Ali MS, et al.
    Nutrients, 2021 Dec 17;13(12).
    PMID: 34960076 DOI: 10.3390/nu13124521
    Diet is a recognized risk factor and cornerstone for chronic kidney disease (CKD) management; however, a tool to assess dietary intake among Bangladeshi dialysis patients is scarce. This study aims to validate a prototype Bangladeshi Hemodialysis Food Frequency Questionnaire (BDHD-FFQ) against 3-day dietary recall (3DDR) and corresponding serum biomarkers. Nutrients of interest were energy, macronutrients, potassium, phosphate, iron, sodium and calcium. The BDHD-FFQ, comprising 132 food items, was developed from 606 24-h recalls and had undergone face and content validation. Comprehensive facets of relative validity were ascertained using six statistical tests (correlation coefficient, percent difference, paired t-test, cross-quartiles classification, weighted kappa, and Bland-Altman analysis). Overall, the BDHD-FFQ showed acceptable to good correlations (p < 0.05) with 3DDR for the concerned nutrients in unadjusted and energy-adjusted models, but this correlation was diminished when adjusted for other covariates (age, gender, and BMI). Phosphate and potassium intake, estimated by the BDHD-FFQ, also correlated well with the corresponding serum biomarkers (p < 0.01) when compared to 3DDR (p > 0.05). Cross-quartile classification indicated that <10% of patients were incorrectly classified. Weighted kappa statistics showed agreement with all but iron. Bland-Altman analysis showed positive mean differences were observed for all nutrients when compared to 3DDR, whilst energy, carbohydrates, fat, iron, sodium, and potassium had percentage data points within the limit of agreement (mean ± 1.96 SD), above 95%. In summary, the BDHD-FFQ demonstrated an acceptable relative validity for most of the nutrients as four out of the six statistical tests fulfilled the cut-off standard in assessing dietary intake of CKD patients in Bangladesh.
  5. Fulltext Statistical Modelling and Characterization of Experimental mm-Wave Indoor Channels for Future 5G Wireless Communication Networks
    Al-Samman AM, Rahman TA, Azmi MH, Hindia MN, Khan I, Hanafi E
    PLoS One, 2016 Sep 21;11(9):e0163034.
    PMID: 27654703 DOI: 10.1371/journal.pone.0163034
    This paper presents an experimental characterization of millimeter-wave (mm-wave) channels in the 6.5 GHz, 10.5 GHz, 15 GHz, 19 GHz, 28 GHz and 38 GHz frequency bands in an indoor corridor environment. More than 4,000 power delay profiles were measured across the bands using an omnidirectional transmitter antenna and a highly directional horn receiver antenna for both co- and cross-polarized antenna configurations. This paper develops a new path-loss model to account for the frequency attenuation with distance, which we term the frequency attenuation (FA) path-loss model and introduce a frequency-dependent attenuation factor. The large-scale path loss was characterized based on both new and well-known path-loss models. A general and less complex method is also proposed to estimate the cross-polarization discrimination (XPD) factor of close-in reference distance with the XPD (CIX) and ABG with the XPD (ABGX) path-loss models to avoid the computational complexity of minimum mean square error (MMSE) approach. Moreover, small-scale parameters such as root mean square (RMS) delay spread, mean excess (MN-EX) delay, dispersion factors and maximum excess (MAX-EX) delay parameters were used to characterize the multipath channel dispersion. Multiple statistical distributions for RMS delay spread were also investigated. The results show that our proposed models are simpler and more physically-based than other well-known models. The path-loss exponents for all studied models are smaller than that of the free-space model by values in the range of 0.1 to 1.4 for all measured frequencies. The RMS delay spread values varied between 0.2 ns and 13.8 ns, and the dispersion factor values were less than 1 for all measured frequencies. The exponential and Weibull probability distribution models best fit the RMS delay spread empirical distribution for all of the measured frequencies in all scenarios.
  6. Fulltext Window-Based Channel Impulse Response Prediction for Time-Varying Ultra-Wideband Channels
    Al-Samman AM, Azmi MH, Rahman TA, Khan I, Hindia MN, Fattouh A
    PLoS One, 2016;11(12):e0164944.
    PMID: 27992445 DOI: 10.1371/journal.pone.0164944
    This work proposes channel impulse response (CIR) prediction for time-varying ultra-wideband (UWB) channels by exploiting the fast movement of channel taps within delay bins. Considering the sparsity of UWB channels, we introduce a window-based CIR (WB-CIR) to approximate the high temporal resolutions of UWB channels. A recursive least square (RLS) algorithm is adopted to predict the time evolution of the WB-CIR. For predicting the future WB-CIR tap of window wk, three RLS filter coefficients are computed from the observed WB-CIRs of the left wk-1, the current wk and the right wk+1 windows. The filter coefficient with the lowest RLS error is used to predict the future WB-CIR tap. To evaluate our proposed prediction method, UWB CIRs are collected through measurement campaigns in outdoor environments considering line-of-sight (LOS) and non-line-of-sight (NLOS) scenarios. Under similar computational complexity, our proposed method provides an improvement in prediction errors of approximately 80% for LOS and 63% for NLOS scenarios compared with a conventional method.
  7. Fulltext Homozygous familial hypercholesterolemia
    Alicezah MK, Razali R, Rahman T, Hoh BP, Suhana NH, Muid S, et al.
    Malays J Pathol, 2014 Aug;36(2):131-7.
    PMID: 25194536 MyJurnal
    We report a rare case of homozygous familial hypercholesterolemia (HoFH), a 22-year-old Malay woman who presented initially with minor soft tissue injury due to a cycling accident. She was then incidentally found to have severe xanthelasma and hypercholesterolemia (serum TC 15.3 mmol/L and LDL-C 13.9 mmol/L). She was referred to the Specialized Lipid Clinic and was diagnosed with familial hypercholesterolemia (FH) based on the Simon Broome (SB) diagnostic criteria. There was a family history of premature coronary heart disease (CHD) in that three siblings had sudden cardiac death, and of consanguineous marriage in that her parents are cousins. DNA screening of LDLR and APOB genes was done by Polymerase Chain Reaction (PCR), followed by Denaturing High Performance Liquid Chromatography (DHPLC). Homozygous mutation C255S in Exon 5 of her LDLR gene was found. There was no mutation was found in Exon 26 and Exon 29 of the APOB gene. This report is to emphasize the importance of identifying patients with FH and cascade screening through established diagnostic criteria and genetic studies in order to ensure early detection and early treatment intervention to minimize the risk of developing CHD and related complications.
  8. A study on the genetic polymorphisms of CYP3A5 among the Orang Asli in Malaysia using a next generation sequencing platform
    Ang GY, Yu CY, Johari James R, Ahmad A, Abdul Rahman T, Mohd Nor F, et al.
    Ann Hum Biol, 2018 Mar;45(2):166-169.
    PMID: 29447003 DOI: 10.1080/03014460.2018.1440004
    BACKGROUND: CYP3A5 is the predominant sub-family of biotransformation enzymes in the liver and the genetic variations in CYP3A5 are an important determinant of inter-individual and inter-ethnic differences in CYP3A-mediated drug disposition and response.

    AIM: This study aims to investigate the genetic polymorphisms of CYP3A5 among the Orang Asli in Peninsular Malaysia using a next generation sequencing platform.

    METHODS: Genomic DNAs were extracted from blood samples of the three main Orang Asli tribes and whole-genome sequencing was performed.

    RESULTS: A total of 61 single nucleotide polymorphisms were identified and all the SNPs were located in introns except rs15524, which is in the 3'UTR, and 11 of these polymorphisms were novel. Two allelic variants and three genotypes were identified in the Orang Asli. The major allelic variant was the non-functional CYP3A5*3 (66.4%). The percentages of Orang Asli with CYP3A5*3/*3 (47.2%) and CYP3A5*1/*3 (38.1%) genotypes are more than twice the percentage of Orang Asli with CYP3A5*1/*1 (14.8%) genotype. Almost half of the Orang Asli harboured CYP3A5 non-expressor genotype (CYP3A5*3/*3).

    CONCLUSIONS: The predominance of the CYP3A5 non-expressor genotype among the Orang Asli was unravelled and the findings in this study may serve as a guide for the optimisation of pharmacotherapy for the Orang Asli community.

  9. Fulltext Detection of CYP2C19 Genetic Variants in Malaysian Orang Asli from Massively Parallel Sequencing Data
    Ang GY, Yu CY, Subramaniam V, Abdul Khalid MI, Tuan Abdu Aziz TA, Johari James R, et al.
    PLoS One, 2016;11(10):e0164169.
    PMID: 27798644 DOI: 10.1371/journal.pone.0164169
    The human cytochrome P450 (CYP) is a superfamily of enzymes that have been a focus in research for decades due to their prominent role in drug metabolism. CYP2C is one of the major subfamilies which metabolize more than 10% of all clinically used drugs. In the context of CYP2C19, several key genetic variations that alter the enzyme's activity have been identified and catalogued in the CYP allele nomenclature database. In this study, we investigated the presence of well-established variants as well as novel polymorphisms in the CYP2C19 gene of 62 Orang Asli from the Peninsular Malaysia. A total of 449 genetic variants were detected including 70 novel polymorphisms; 417 SNPs were located in introns, 23 in upstream, 7 in exons, and 2 in downstream regions. Five alleles and seven genotypes were inferred based on the polymorphisms that were found. Null alleles that were observed include CYP2C19*3 (6.5%), *2 (5.7%) and *35 (2.4%) whereas allele with increased function *17 was detected at a frequency of 4.8%. The normal metabolizer genotype was the most predominant (66.1%), followed by intermediate metabolizer (19.4%), rapid metabolizer (9.7%) and poor metabolizer (4.8%) genotypes. Findings from this study provide further insights into the CYP2C19 genetic profile of the Orang Asli as previously unreported variant alleles were detected through the use of massively parallel sequencing technology platform. The systematic and comprehensive analysis of CYP2C19 will allow uncharacterized variants that are present in the Orang Asli to be included in the genotyping panel in the future.
  10. Fulltext Multi Beam Dielectric Lens Antenna for 5G Base Station
    Ansarudin F, Abd Rahman T, Yamada Y, Rahman NHA, Kamardin K
    Sensors (Basel), 2020 Oct 16;20(20).
    PMID: 33081110 DOI: 10.3390/s20205849
    In the 5G mobile system, new features such as millimetre wave operation, small cell size and multi beam are requested at base stations. At millimetre wave, the base station antennas become very small in size, which is about 30 cm; thus, dielectric lens antennas that have excellent multi beam radiation pattern performance are suitable candidates. For base station application, the lens antennas with small thickness and small curvature are requested for light weight and ease of installation. In this paper, a new lens shaping method for thin and small lens curvature is proposed. In order to develop the thin lens antenna, comparisons of antenna structures with conventional aperture distribution lens and Abbe's sine lens are made. Moreover, multi beam radiation pattern of three types of lenses are compared. As a result, the thin and small curvature of the proposed lens and an excellent multi beam radiation pattern are ensured.
  11. Multilevel Pharmacological Effects of Antipsychotics in Potential Glioblastoma Treatment
    Awuah WA, Kalmanovich J, Mehta A, Huang H, Abdul-Rahman T, Cheng Ng J, et al.
    Curr Top Med Chem, 2023;23(5):389-402.
    PMID: 36593538 DOI: 10.2174/1568026623666230102095836
    Glioblastoma Multiforme (GBM) is a debilitating type of brain cancer with a high mortality rate. Despite current treatment options such as surgery, radiotherapy, and the use of temozolomide and bevacizumab, it is considered incurable. Various methods, such as drug repositioning, have been used to increase the number of available treatments. Drug repositioning is the use of FDA-approved drugs to treat other diseases. This is possible because the drugs used for this purpose have polypharmacological effects. This means that these medications can bind to multiple targets, resulting in multiple mechanisms of action. Antipsychotics are one type of drug used to treat GBM. Antipsychotics are a broad class of drugs that can be further subdivided into typical and atypical classes. Typical antipsychotics include chlorpromazine, trifluoperazine, and pimozide. This class of antipsychotics was developed early on and primarily works on dopamine D2 receptors, though it can also work on others. Olanzapine and Quetiapine are examples of atypical antipsychotics, a category that was created later. These medications have a high affinity for serotonin receptors such as 5- HT2, but they can also act on dopamine and H1 receptors. Antipsychotic medications, in the case of GBM, also have other effects that can affect multiple pathways due to their polypharmacological effects. These include NF-B suppression, cyclin deregulation, and -catenin phosphorylation, among others. This review will delve deeper into the polypharmacological, the multiple effects of antipsychotics in the treatment of GBM, and an outlook for the field's future progression.
  12. In Reply: The State of Cerebrovascular Care in Africa
    Awuah WA, Tenkorang PO, Ng JC, Abdul-Rahman T
    Neurosurgery, 2023 Jul 01;93(1):e16.
    PMID: 37097024 DOI: 10.1227/neu.0000000000002515
  13. The unmet need of organ transplantation in Africa
    Awuah WA, Ng JC, Bulut HI, Nazir A, Tenkorang PO, Yarlagadda R, et al.
    Int J Surg, 2023 Mar 01;109(3):519-520.
    PMID: 36927835 DOI: 10.1097/JS9.0000000000000025
  14. Ailing neurosurgical services in rural Africa
    Awuah WA, Adebusoye FT, Tenkorang PO, Mehta A, Mustapha MJ, Debrah AF, et al.
    Int J Surg, 2023 Mar 01;109(3):227-229.
    PMID: 36906787 DOI: 10.1097/JS9.0000000000000020
  15. The African cancer burden: what is the potential role of modern oncology innovation in reducing the continent's rapidly rising mortality?
    Awuah WA, Ng JC, Mehta A, Nansubuga EP, Abdul-Rahman T, Kundu M, et al.
    Postgrad Med J, 2023 Aug 22;99(1175):941-945.
    PMID: 37280156 DOI: 10.1093/postmj/qgad043
    With increasing prevalence and an expected rise in disease burden, cancer is a cause of concern for African healthcare. The cancer burden in Africa is expected to rise to 2.1 million new cases per year and 1.4 million deaths annually by the year 2040. Even though efforts are being made to improve the standard of oncology service delivery in Africa, the current state of cancer care is not yet on par with the rise in the cancer burden. Cutting-edge technologies and innovations are being developed across the globe to augment the battle against cancer; however, many of them are beyond the reach of African countries. Modern oncology innovations targeted to ward Africa would be promising to address the high cancer mortality rates. The innovations should be cost-effective and widely accessible to tackle the rapidly rising mortality rate on the African continent. Though it may seem promising, a multidisciplinary approach is required to overcome the challenges associated with the development and implementation of modern oncology innovations in Africa.
  16. Fulltext Circadian rhythm in systemic autoimmune conditions: Potential of chrono-immunology in clinical practice: A narrative review
    Awuah WA, Huang H, Kalmanovich J, Mehta A, Mikhailova T, Ng JC, et al.
    Medicine (Baltimore), 2023 Aug 11;102(32):e34614.
    PMID: 37565922 DOI: 10.1097/MD.0000000000034614
    The circadian rhythm (CR) is a fundamental biological process regulated by the Earth's rotation and solar cycles. It plays a critical role in various bodily functions, and its dysregulation can have systemic effects. These effects impact metabolism, redox homeostasis, cell cycle regulation, gut microbiota, cognition, and immune response. Immune mediators, cycle proteins, and hormones exhibit circadian oscillations, supporting optimal immune function and defence against pathogens. Sleep deprivation and disruptions challenge the regulatory mechanisms, making immune responses vulnerable. Altered CR pathways have been implicated in diseases such as diabetes, neurological conditions, and systemic autoimmune diseases (SADs). SADs involve abnormal immune responses to self-antigens, with genetic and environmental factors disrupting self-tolerance and contributing to conditions like Systemic Lupus Erythematosus, Rheumatoid Arthritis, and Inflammatory Myositis. Dysregulated CR may lead to increased production of pro-inflammatory cytokines, contributing to the systemic responses observed in SADs. Sleep disturbances significantly impact the quality of life of patients with SADs; however, they are often overlooked. The relationship between sleep and autoimmune conditions, whether causal or consequential to CR dysregulation, remains unclear. Chrono-immunology investigates the role of CR in immunity, offering potential for targeted therapies in autoimmune conditions. This paper provides an overview of the connections between sleep and autoimmune conditions, highlighting the importance of recognizing sleep disturbances in SADs and the need for further research into the complex relationship between the CR and autoimmune diseases.
  17. Fulltext Postoperative mortality in Africa: are there any improvements in the last decade?
    Awuah WA, Ng JC, Nazir A, Tenkorang PO, Yarlagadda R, Kalmanovich J, et al.
    Int J Surg, 2023 May 01;109(5):1080-1082.
    PMID: 36927691 DOI: 10.1097/JS9.0000000000000125
  18. The molecular landscape of neurological disorders: insights from single-cell RNA sequencing in neurology and neurosurgery
    Awuah WA, Ahluwalia A, Ghosh S, Roy S, Tan JK, Adebusoye FT, et al.
    Eur J Med Res, 2023 Nov 16;28(1):529.
    PMID: 37974227 DOI: 10.1186/s40001-023-01504-w
    Single-cell ribonucleic acid sequencing (scRNA-seq) has emerged as a transformative technology in neurological and neurosurgical research, revolutionising our comprehension of complex neurological disorders. In brain tumours, scRNA-seq has provided valuable insights into cancer heterogeneity, the tumour microenvironment, treatment resistance, and invasion patterns. It has also elucidated the brain tri-lineage cancer hierarchy and addressed limitations of current models. Neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis have been molecularly subtyped, dysregulated pathways have been identified, and potential therapeutic targets have been revealed using scRNA-seq. In epilepsy, scRNA-seq has explored the cellular and molecular heterogeneity underlying the condition, uncovering unique glial subpopulations and dysregulation of the immune system. ScRNA-seq has characterised distinct cellular constituents and responses to spinal cord injury in spinal cord diseases, as well as provided molecular signatures of various cell types and identified interactions involved in vascular remodelling. Furthermore, scRNA-seq has shed light on the molecular complexities of cerebrovascular diseases, such as stroke, providing insights into specific genes, cell-specific expression patterns, and potential therapeutic interventions. This review highlights the potential of scRNA-seq in guiding precision medicine approaches, identifying clinical biomarkers, and facilitating therapeutic discovery. However, challenges related to data analysis, standardisation, sample acquisition, scalability, and cost-effectiveness need to be addressed. Despite these challenges, scRNA-seq has the potential to transform clinical practice in neurological and neurosurgical research by providing personalised insights and improving patient outcomes.
  19. 3D printing in surgery: revolutionizing trauma and fracture care in low and middle-income countries
    Awuah WA, Tenkorang PO, Adebusoye FT, Ng JC, Wellington J, Abdul-Rahman T, et al.
    Postgrad Med J, 2023 Dec 21;100(1179):1-3.
    PMID: 37857514 DOI: 10.1093/postmj/qgad100
  20. Fulltext Exploring the current landscape of single-cell RNA sequencing applications in gastric cancer research
    Awuah WA, Roy S, Tan JK, Adebusoye FT, Qiang Z, Ferreira T, et al.
    J Cell Mol Med, 2024 Apr;28(7):e18159.
    PMID: 38494861 DOI: 10.1111/jcmm.18159
    Gastric cancer (GC) represents a major global health burden and is responsible for a significant number of cancer-related fatalities. Its complex nature, characterized by heterogeneity and aggressive behaviour, poses considerable challenges for effective diagnosis and treatment. Single-cell RNA sequencing (scRNA-seq) has emerged as an important technique, offering unprecedented precision and depth in gene expression profiling at the cellular level. By facilitating the identification of distinct cell populations, rare cells and dynamic transcriptional changes within GC, scRNA-seq has yielded valuable insights into tumour progression and potential therapeutic targets. Moreover, this technology has significantly improved our comprehension of the tumour microenvironment (TME) and its intricate interplay with immune cells, thereby opening avenues for targeted therapeutic strategies. Nonetheless, certain obstacles, including tumour heterogeneity and technical limitations, persist in the field. Current endeavours are dedicated to refining protocols and computational tools to surmount these challenges. In this narrative review, we explore the significance of scRNA-seq in GC, emphasizing its advantages, challenges and potential applications in unravelling tumour heterogeneity and identifying promising therapeutic targets. Additionally, we discuss recent developments, ongoing efforts to overcome these challenges, and future prospects. Although further enhancements are required, scRNA-seq has already provided valuable insights into GC and holds promise for advancing biomedical research and clinical practice.
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