Displaying publications 21 - 40 of 54 in total

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  1. Hassim NA, Hambali K, Idris NSU, Amir A, Ismail A, Zulkifli SZ, et al.
    Trop Life Sci Res, 2018 Jul;29(2):175-186.
    PMID: 30112148 MyJurnal DOI: 10.21315/tlsr2018.29.2.12
    Long-tailed macaque (Macaca fascicularis) has the potential to be a good biological indicator for toxic exposure because they have an almost similar physiology and behaviour to humans. The objective of this study is to determine the concentration of lead (Pb) in hair samples of long-tailed macaques which were found in and out of the Kuala Selangor Nature Park (KSNP) area. The hypothesis is long-tailed macaques that live in the anthropogenic area (outside KSNP) may be exposed to high levels of lead compared to long-tailed macaques living in the forest area (inside KSNP). Analysis of hair samples were carried out using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The study found that the average mean of lead concentration in the anthropogenic area is 6.31 μg/g while for the forest area it is 3.16 μg/g. Lead concentration in the two areas are statistically insignificant. Nevertheless, lead concentration in the anthropogenic area recorded a slightly higher mean concentration than in the forest area. Even so, results of this study indicate that long-tailed macaques in Kuala Selangor are not exposed to high levels of lead. This study is the first in Malaysia to utilise long-tailed macaques as a biological indicator for testing the concentration of toxic substances in the environment. This study is still in its early stages; thus, future research requires improvements.
  2. Amir A, Cheong FW, de Silva JR, Liew JWK, Lau YL
    Infect Drug Resist, 2018;11:1145-1155.
    PMID: 30127631 DOI: 10.2147/IDR.S148664
    Originally known to cause simian malaria, Plasmodium knowlesi is now known as the fifth human malaria species. Since the publishing of a report that largely focused on human knowlesi cases in Sarawak in 2004, many more human cases have been reported in nearly all of the countries in Southeast Asia and in travelers returning from these countries. The zoonotic nature of this infection hinders malaria elimination efforts. In order to grasp the current perspective of knowlesi malaria, this literature review explores the different aspects of the disease including risk factors, diagnosis, treatment, and molecular and functional studies. Current studies do not provide sufficient data for an effective control program. Therefore, future direction for knowlesi research is highlighted here with a final aim of controlling, if not eliminating, the parasite.
  3. Abdalkareem ZA, Amir A, Al-Betar MA, Ekhan P, Hammouri AI
    Health Technol (Berl), 2021;11(3):445-469.
    PMID: 33868893 DOI: 10.1007/s12553-021-00547-5
    This paper offers a summary of the latest studies on healthcare scheduling problems including patients' admission scheduling problem, nurse scheduling problem, operation room scheduling problem, surgery scheduling problem and other healthcare scheduling problems. The paper provides a comprehensive survey on healthcare scheduling focuses on the recent literature. The development of healthcare scheduling research plays a critical role in optimizing costs and improving the patient flow, providing prompt administration of treatment, and the optimal use of the resources provided and accessible in the hospitals. In the last decades, the healthcare scheduling methods that aim to automate the search for optimal resource management in hospitals by using metaheuristics methods have proliferated. However, the reported results are disintegrated since they solved every specific problem independently, given that there are many versions of problem definition and various data sets available for each of these problems. Therefore, this paper integrates the existing results by performing a comprehensive review and analyzing 190 articles based on four essential components in solving optimization problems: problem definition, formulations, data sets, and methods. This paper summarizes the latest healthcare scheduling problems focusing on patients' admission scheduling problems, nurse scheduling problems, and operation room scheduling problems considering these are the most common issues found in the literature. Furthermore, this review aims to help researchers to highlight some development from the most recent papers and grasp the new trends for future directions.
  4. Abdalkareem ZA, Al-Betar MA, Amir A, Ehkan P, Hammouri AI, Salman OH
    Comput Biol Med, 2022 Feb;141:105007.
    PMID: 34785077 DOI: 10.1016/j.compbiomed.2021.105007
    This paper aims to tackle the Patient Admission Scheduling Problem (PASP) using the Discrete Flower Pollination Algorithm (DFPA), a new, meta-heuristic optimization method based on plant pollination. PASP is one of the most important problems in the field of health care. It is a highly constrained and combinatorial optimization problem of assigning patients to medical resources in a hospital, subject to predefined constraints, while maximizing patient comfort. While the flower pollination algorithm was designed for continuous optimization domains, a discretization of the algorithm has been carried out for application to the PASP. Various neighborhood structures have been employed to enhance the method, and to explore more solutions in the search space. The proposed method has been tested on six instances of benchmark datasets for comparison against another algorithm using the same dataset. The prospective method is shown to be very efficient in solving any scheduling problem.
  5. Liew J, Amir A, Chen Y, Fong MY, Razali R, Lau YL
    Clin Chim Acta, 2015 Aug 25;448:33-8.
    PMID: 26086445 DOI: 10.1016/j.cca.2015.06.006
    Autoantibodies or antibodies against self-antigens are produced either during physiological processes to maintain homeostasis or pathological process such as trauma and infection. Infection with parasites including Plasmodium has been shown to generally induce elevated self-antibody (autoantibody) levels. Plasmodium knowlesi is increasingly recognized as one of the most important emerging human malaria in Southeast Asia that can cause severe infection leading to mortality. Autoimmune-like phenomena have been hypothesized to play a role in the protective immune responses in malaria infection.
  6. Mahendran P, Liew JWK, Amir A, Ching XT, Lau YL
    Malar J, 2020 Jul 10;19(1):241.
    PMID: 32650774 DOI: 10.1186/s12936-020-03314-5
    BACKGROUND: Plasmodium knowlesi and Plasmodium vivax are the predominant Plasmodium species that cause malaria in Malaysia and play a role in asymptomatic malaria disease transmission in Malaysia. The diagnostic tools available to diagnose malaria, such as microscopy and rapid diagnostic test (RDT), are less sensitive at detecting lower parasite density. Droplet digital polymerase chain reaction (ddPCR), which has been shown to have higher sensitivity at diagnosing malaria, allows direct quantification without the need for a standard curve. The aim of this study is to develop and use a duplex ddPCR assay for the detection of P. knowlesi and P. vivax, and compare this method to nested PCR and qPCR.

    METHODS: The concordance rate, sensitivity and specificity of the duplex ddPCR assay were determined and compared to nested PCR and duplex qPCR.

    RESULTS: The duplex ddPCR assay had higher analytical sensitivity (P. vivax = 10 copies/µL and P. knowlesi = 0.01 copies/µL) compared to qPCR (P. vivax = 100 copies/µL and P. knowlesi = 10 copies/µL). Moreover, the ddPCR assay had acceptable clinical sensitivity (P. vivax = 80% and P. knowlesi = 90%) and clinical specificity (P. vivax = 87.84% and P. knowlesi = 81.08%) when compared to nested PCR. Both ddPCR and qPCR detected more double infections in the samples.

    CONCLUSIONS: Overall, the ddPCR assay demonstrated acceptable efficiency in detection of P. knowlesi and P. vivax, and was more sensitive than nested PCR in detecting mixed infections. However, the duplex ddPCR assay still needs optimization to improve the assay's clinical sensitivity and specificity.

  7. Ali RH, Almanabri M, Ali NY, Alsaber AR, Khalifa NM, Hussein R, et al.
    J Clin Pathol, 2024 Jan 09.
    PMID: 38195220 DOI: 10.1136/jcp-2023-209318
    AIMS: Mitogen-activated protein kinase (MAPK) pathway alteration is a major oncogenic driver in paediatric low-grade gliomas (LGG) and some adult gliomas, encompassing BRAF (most common) and non-BRAF alterations. The aim was to determine the frequency, molecular spectrum and clinicopathological features of MAPK-altered gliomas in paediatric and adult patients at our neuropathology site in Kuwait.

    METHODS: We retrospectively searched the data of molecularly sequenced gliomas between 2018 and 2023 for MAPK alterations, revised the pathology in view of the 2021 WHO classification and evaluated the clinicopathological data for possible correlations.

    RESULTS: Of 272 gliomas, 40 (15%) harboured a MAPK pathway alteration in 19 paediatric (median 9.6 years; 1.2-17.6) and 21 adult patients (median 37 years; 18.9-89.2), comprising 42% and 9% of paediatric and adult cases, respectively. Pilocytic astrocytoma and glioblastoma were the most frequent diagnoses in children (47%) and adults (43%), respectively. BRAF V600E (n=17, 43%) showed a wide distribution across age groups, locations and pathological diagnoses while KIAA1549::BRAF fusion (n=8, 20%) was spatially and histologically restricted to cerebellar paediatric LGGs. Non-V600E variants and BRAF amplifications accompanied other molecular aberrations in high-grade tumours. Non-BRAF MAPK alterations (n=8) included mutations and gene fusions involving FGFR1, NTRK2, NF1, ROS1 and MYB. Fusions included KANK1::NTRK2, GOPC::ROS1 (both infant hemispheric gliomas), FGFR1::TACC1 (diffuse LGG), MYB::QKI (angiocentric glioma) and BCR::NTRK2 (glioblastoma). Paradoxical H3 K27M/MAPK co-mutations were observed in two LGGs.

    CONCLUSION: The study provided insights into MAPK-altered gliomas in Kuwait highlighting the differences among paediatric and adult patients and providing a framework for planning therapeutic polices.

  8. Friess DA, Thompson BS, Brown B, Amir AA, Cameron C, Koldewey HJ, et al.
    Conserv Biol, 2016 10;30(5):933-49.
    PMID: 27341487 DOI: 10.1111/cobi.12784
    Many drivers of mangrove forest loss operate over large scales and are most effectively addressed by policy interventions. However, conflicting or unclear policy objectives exist at multiple tiers of government, resulting in contradictory management decisions. To address this, we considered four approaches that are being used increasingly or could be deployed in Southeast Asia to ensure sustainable livelihoods and biodiversity conservation. First, a stronger incorporation of mangroves into marine protected areas (that currently focus largely on reefs and fisheries) could resolve some policy conflicts and ensure that mangroves do not fall through a policy gap. Second, examples of community and government comanagement exist, but achieving comanagement at scale will be important in reconciling stakeholders and addressing conflicting policy objectives. Third, private-sector initiatives could protect mangroves through existing and novel mechanisms in degraded areas and areas under future threat. Finally, payments for ecosystem services (PES) hold great promise for mangrove conservation, with carbon PES schemes (known as blue carbon) attracting attention. Although barriers remain to the implementation of PES, the potential to implement them at multiple scales exists. Closing the gap between mangrove conservation policies and action is crucial to the improved protection and management of this imperiled coastal ecosystem and to the livelihoods that depend on them.
  9. Amir A, Ngui R, Ismail WH, Wong KT, Ong JS, Lim YA, et al.
    Am J Trop Med Hyg, 2016 Aug 03;95(2):410-2.
    PMID: 27325803 DOI: 10.4269/ajtmh.16-0007
    Human anisakiasis is a zoonosis acquired by eating raw or undercooked infected seafood. Herein, we report a case of acute dysentery caused by anisakiasis in a 64-year-old man in Malaysia. A colonoscopy was performed and a nematode larva was found penetrating the mucosa of the ascending colon. Bleeding was observed at the site of penetration. Y-shaped lateral epidermal cords were seen from the cross section of the worm, which is a prominent feature of Anisakis larva. Molecular analysis using polymerase chain reaction of cytochrome oxidase 2 (cox2) gene confirmed the specimen to be larva of Anisakis simplex.
  10. Sum JS, Lee WC, Amir A, Braima KA, Jeffery J, Abdul-Aziz NM, et al.
    Parasit Vectors, 2014;7:309.
    PMID: 24993022 DOI: 10.1186/1756-3305-7-309
    Molecular techniques are invaluable for investigation on the biodiversity of Anopheles mosquitoes. This study aimed at investigating the spatial-genetic variations among Anopheles mosquitoes from different areas of Peninsular Malaysia, as well as deciphering evolutionary relationships of the local Anopheles mosquitoes with the mosquitoes from neighbouring countries using the anopheline ITS2 rDNA gene.
  11. Angal L, Mahmud R, Samin S, Yap NJ, Ngui R, Amir A, et al.
    BMC Infect Dis, 2015 Oct 29;15:467.
    PMID: 26511347 DOI: 10.1186/s12879-015-1178-3
    BACKGROUND: The prison management in Malaysia is proactively seeking to improve the health status of the prison inmates. Intestinal parasitic infections (IPIs) are widely distributed throughout the world and are still gaining great concern due to their significant morbidity and mortality among infected humans. In Malaysia, there is a paucity of information on IPIs among prison inmates. In order to further enhance the current health strategies employed, the present study aims to establish firm data on the prevalence and diversity of IPIs among HIV-infected and non-HIV-infected individuals in a prison, an area in which informed knowledge is still very limited.

    METHODS: Samples were subjected to microscopy examination and serological test (only for Strongyloides). Speciation for parasites on microscopy-positive samples and seropositive samples for Strongyloides were further determined via polymerase chain reaction. SPSS was used for statistical analysis.

    RESULTS: A total of 294 stool and blood samples each were successfully collected, involving 131 HIV positive and 163 HIV negative adult male inmates whose age ranged from 21 to 69-years-old. Overall prevalence showed 26.5% was positive for various IPIs. The IPIs detected included Blastocystis sp., Strongyloides stercoralis, Entamoeba spp., Cryptosporidium spp., Giardia spp., and Trichuris trichiura. Comparatively, the rate of IPIs was slightly higher among the HIV positive inmates (27.5%) than HIV negative inmates (25.8%). Interestingly, seropositivity for S. stercoralis was more predominant in HIV negative inmates (10.4%) compared to HIV-infected inmates (6.9%), however these findings were not statistically significant. Polymerase chain reaction (PCR) confirmed the presence of Blastocystis, Strongyloides, Entamoeba histolytica and E. dispar.

    CONCLUSIONS: These data will enable the health care providers and prison management staff to understand the trend and epidemiological situations in HIV/parasitic co-infections in a prison. This information will further assist in providing evidence-based guidance to improve prevention, control and management strategies of IPIs co-infections among both HIV positive and HIV negative inmates in a prison environment.

  12. Amir A, Russell B, Liew JW, Moon RW, Fong MY, Vythilingam I, et al.
    Sci Rep, 2016 Apr 21;6:24623.
    PMID: 27097521 DOI: 10.1038/srep24623
    Plasmodium knowlesi is extensively used as an important malaria model and is now recognized as an important cause of human malaria in Malaysia. The strains of P. knowlesi currently used for research were isolated many decades ago, raising concerns that they might no longer be representative of contemporary parasite populations. We derived a new P. knowlesi line (University Malaya line, UM01), from a patient admitted in Kuala Lumpur, Malaysia, and compared it with a human-adapted laboratory line (A1-H.1) derived from the P. knowlesi H strain. The UM01 and A1-H.1 lines readily invade human and macaque (Macaca fascicularis) normocytes with a preference for reticulocytes. Whereas invasion of human red blood cells was dependent on the presence of the Duffy antigen/receptor for chemokines (DARC) for both parasite lines, this was not the case for macaque red blood cells. Nonetheless, differences in invasion efficiency, gametocyte production and the length of the asexual cycle were noted between the two lines. It would be judicious to isolate and characterise numerous P. knowlesi lines for use in future experimental investigations of this zoonotic species.
  13. Ali MF, Abdul Aziz AF, Rashid MR, Che Man Z, Amir AA, Lim YS, et al.
    Med J Malaysia, 2015 Feb;70(1):18-23.
    PMID: 26032524
    INTRODUCTION: The lack of evidence that proves the benefit of traditional and complementary medicines (T & CM) in treating chronic medical conditions does not deter its usage among patients worldwide. Prevalence of usage among post-stroke patients in Malaysia especially is unknown. This study aims to determine the prevalence, practice and perception of T & CM use among stroke survivors attending an outpatient rehabilitation program in a teaching hospital.
    METHODS: A cross-sectional study was conducted among 104 post stroke patients attending an outpatient rehabilitation program. A structured self-administered questionnaire was used to collect data on sociodemographic and clinical profile of patients, as well as types of therapy used and perception on T & CM usage. Descriptive analysis was done, and bivariate analysis was used to determine associations between categorical data.
    RESULTS: Mean age of patients was 62 years (SD 12.2), 54% were Chinese and 75% of the patients had ischaemic stroke. Mean age of T & CM users was younger compared to non- T & CM users (61 years vs. 66 years, p=0.04). Two-thirds (66%) of patients admitted to concurrent T & CM usage while attending conventional post stroke rehabilitation. Acupuncture (40.4%), massage (40.4%) and traditional Chinese medicine (11.5%) were the most common T & CM used. Positive perception was recorded in terms of ability of T & CM usage to relieve post stroke symptoms (68%), and it was safe to use because it was made from 'natural sources'. Negative perception recorded: T & CM caused significant adverse effects (57.6%) and was not safe to be used in combination with other conventional medicines (62.5%).
    CONCLUSIONS: Concurrent T & CM usage among post-stroke patients attending structured outpatient rehabilitation program is widely practised especially acupuncture, massage and traditional Chinese medicines. Overall the perception towards its use is favourable.
    Study site: Medical Rehabilitation Services Department, Perubatan Universiti Kebangsaan Malaysia (PPUKM), Kuala Lumpur, Malaysia
  14. Rajoo Y, Mahmud R, Xiang NR, Omar SF, Kumar G, Lim YA, et al.
    Asian Pac J Trop Med, 2015 Apr;8(4):334-6.
    PMID: 25975509 DOI: 10.1016/S1995-7645(14)60341-2
    We report a case of a patient with Schistosoma mansoni infection who presented with liver cirrhosis and splenomegaly. She was diagnosed by a serological test and Kato-Katz thick smear stool examination. The patient was a 52-year-old woman from Sudan who came to Malaysia for a week to visit her sons. The patient lives in the middle of Rabak region, Sudan, a highly endemic area for schistosomiasis where her daily routine includes rearing of cows and farming. The site of toilet and sources of drinking water are canals and wells; both infested with snails. Patient had a long history of exposure and coming into contact with water from these canals and wells.
  15. van Schalkwyk DA, Blasco B, Davina Nuñez R, Liew JWK, Amir A, Lau YL, et al.
    PMID: 30831468 DOI: 10.1016/j.ijpddr.2019.02.004
    New antimalarial agents are identified and developed after extensive testing on Plasmodium falciparum parasites that can be grown in vitro. These susceptibility studies are important to inform lead optimisation and support further drug development. Until recently, little was known about the susceptibility of non-falciparum species as these had not been adapted to in vitro culture. The recent culture adaptation of P. knowlesi has therefore offered an opportunity to routinely define the drug susceptibility of this species, which is phylogenetically closer to all other human malarias than is P. falciparum. We compared the in vitro susceptibility of P. knowlesi and P. falciparum to a range of established and novel antimalarial agents under identical assay conditions. We demonstrated that P. knowlesi is significantly less susceptible than P. falciparum to six of the compounds tested; and notably these include three ATP4 inhibitors currently under development as novel antimalarial agents, and one investigational antimalarial, AN13762, which is 67 fold less effective against P. knowlesi. For the other compounds there was a less than two-fold difference in susceptibility between species. We then compared the susceptibility of a recent P. knowlesi isolate, UM01, to that of the well-established, older A1-H.1 clone. This recent isolate showed similar in vitro drug susceptibility to the A1-H.1 clone, supporting the ongoing use of the better characterised clone to further study drug susceptibility. Lastly, we used isobologram analysis to explore the interaction of a selection of drug combinations and showed similar drug interactions across species. The species differences in drug susceptibility reported by us here and previously, support adding in vitro drug screens against P. knowlesi to those using P. falciparum strains to inform new drug discovery and lead optimisation.
  16. Lau YL, Lee WC, Chen J, Zhong Z, Jian J, Amir A, et al.
    PLoS One, 2016;11(6):e0157893.
    PMID: 27347683 DOI: 10.1371/journal.pone.0157893
    Anopheles cracens has been incriminated as the vector of human knowlesi malaria in peninsular Malaysia. Besides, it is a good laboratory vector of Plasmodium falciparum and P. vivax. The distribution of An. cracens overlaps with that of An. maculatus, the human malaria vector in peninsular Malaysia that seems to be refractory to P. knowlesi infection in natural settings. Whole genome sequencing was performed on An. cracens and An. maculatus collected here. The draft genome of An. cracens was 395 Mb in size whereas the size of An. maculatus draft genome was 499 Mb. Comparison with the published Malaysian An. maculatus genome suggested the An. maculatus specimen used in this study as a different geographical race. Comparative analyses highlighted the similarities and differences between An. cracens and An. maculatus, providing new insights into their biological behavior and characteristics.
  17. Ahmad AF, Ngui R, Ong J, Sarip F, Ismail WHW, Omar H, et al.
    Am J Trop Med Hyg, 2017 Jul;97(1):163-165.
    PMID: 28719332 DOI: 10.4269/ajtmh.15-0877
    A case of Hymenolepis diminuta infection in a 43-year-old Malaysian male with persistent abdominal colicky pain is reported. Endoscopy revealed whitish worms in the lumen of the small intestine, which were identified as H. diminuta after microscopy. Patient was successfully treated with a single dose of praziquantel (25 mg/kg).
  18. Lee WC, Cheong FW, Amir A, Lai MY, Tan JH, Phang WK, et al.
    Malar J, 2023 Oct 19;22(1):316.
    PMID: 37858164 DOI: 10.1186/s12936-023-04732-x
  19. Latif ENM, Noordin NR, Shahari S, Amir A, Lau YL, Cheong FW, et al.
    Parasitol Res, 2024 Jan 19;123(1):105.
    PMID: 38240877 DOI: 10.1007/s00436-024-08125-0
    Plasmodium cynomolgi is a simian malaria parasite that has been increasingly infecting humans. It is naturally present in the long-tailed and pig-tailed macaques in Southeast Asia. The P. cynomolgi Duffy binding protein 1 region II [PcDBP1(II)] plays an essential role in the invasion of the parasite into host erythrocytes. This study investigated the genetic polymorphism, natural selection and haplotype clustering of PcDBP1(II) from wild macaque isolates in Peninsular Malaysia. The genomic DNA of 50 P. cynomolgi isolates was extracted from the macaque blood samples. Their PcDBP1(II) gene was amplified using a semi-nested PCR, cloned into a plasmid vector and subsequently sequenced. The polymorphism, natural selection and haplotypes of PcDBP1(II) were analysed using MEGA X and DnaSP ver.6.12.03 programmes. The analyses revealed high genetic polymorphism of PcDBP1(II) (π = 0.026 ± 0.004; Hd = 0.996 ± 0.001), and it was under purifying (negative) selection. A total of 106 haplotypes of PcDBP1(II) were identified. Phylogenetic and haplotype analyses revealed two groups of PcDBP1(II). Amino acid length polymorphism was observed between the groups, which may lead to possible phenotypic difference between them.
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