Displaying publications 61 - 80 of 247 in total

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  1. Haerian BS, Lim KS, Tan HJ, Mohamed EH, Tan CT, Raymond AA, et al.
    Epileptic Disord, 2011 Mar;13(1):65-75.
    PMID: 21388909 DOI: 10.1684/epd.2011.0419
    Over-expression of P-glycoprotein, encoded by the ABCB1 gene, is proposed to be involved in resistance to antiepileptic drugs in about 30% of patients with epilepsy. Here, we investigated the possible association between ABCB1 polymorphisms and sodium valproate (VPA) treatment in Malaysian epilepsy patients. Genotypes were assessed in 249 drug-resistant and 256 drug-responsive Malaysian patients for C1236T, G2677T/A, and C 5T polymorphisms in the ABCB1 gene. No genotypes, alleles, or haplotypes were associated with the response to VPA in either the overall group or Chinese, Indian, and Malay subgroups. Our data suggest that C1236T, G2677T/A, and C3435T polymorphisms in the ABCB1 gene do not contribute to the response to VPA in patients with epilepsy.
  2. Haerian BS, Lim KS, Tan CT, Raymond AA, Mohamed Z
    Pharmacogenomics, 2011 May;12(5):713-25.
    PMID: 21391884 DOI: 10.2217/pgs.10.212
    Several studies demonstrated a link between ABCB1 gene variants and the response to treatment in epilepsy, but the results have been inconclusive. Here, we performed the first haplotype meta-analysis to examine the association of haplotypes of ABCB1 common variants with the response to treatment in epilepsy.
  3. Haerian BS, Roslan H, Raymond AA, Tan CT, Lim KS, Zulkifli SZ, et al.
    Seizure, 2010 Jul;19(6):339-46.
    PMID: 20605481 DOI: 10.1016/j.seizure.2010.05.004
    The C3435T, a major allelic variant of the ABCB1 gene, is proposed to play a crucial role in drug-resistance in epilepsy. The C/C genotype carriers reportedly are at higher risk of pharmacoresistance to AEDs, but only in some studies. The hypothesis of the C-variant associated risk and resistance to antiepileptic drugs (AEDs) has been hampered by conflicting results from inadequate power in case-control studies. To assess the role of C3435T polymorphism in drug-resistance in epilepsy, a systematic review and meta-analysis was conducted.
  4. Haerian BS, Lim KS, Mohamed EH, Tan HJ, Tan CT, Raymond AA, et al.
    Seizure, 2011 Jun;20(5):387-94.
    PMID: 21316268 DOI: 10.1016/j.seizure.2011.01.008
    It is proposed that overexpression of P-glycoprotein (P-gp), encoded by the ABC subfamily B member 1 (ABCB1) gene, is involved in resistance to antiepileptic drugs (AEDs) in about 30% of patients with epilepsy. Genetic variation and haplotype patterns are population specific which may cause different phenotypes such as response to AEDs. Although several studies examined the link between the common polymorphisms in the ABCB1 gene with resistance to AEDs, the results have been conflicting. This controversy may be caused by the effect of some confounders such as ethnicity and polytherapy. Moreover, expression of the ABCB1 gene is under the control of pregnane X receptor (PXR). Evidence showed that PXR gene contribute to the response to treatment. The aim of this study was to assess the association of ABCB1 and PXR genetic polymorphisms with response to the carbamazepine (CBZ) or sodium valproate (VPA) monotherapy in epilepsy. Genotypes were assessed in 685 Chinese, Indian, and Malay epilepsy patients for ABCB1 (C1236T, G2677T, C3435T) and PXR (G7635A) polymorphisms. No association between these polymorphisms and their haplotypes, and interaction between them, with response to treatment was observed in the overall group or in the Chinese, Indian, and Malay subgroups. Our data showed that these polymorphisms may not contribute to the response to CBZ or VPA monotherapy treatment in epilepsy.
  5. Haerian BS, Baum L, Kwan P, Cherny SS, Shin JG, Kim SE, et al.
    Mol Neurobiol, 2016 10;53(8):5457-67.
    PMID: 26452361 DOI: 10.1007/s12035-015-9457-y
    Gamma-aminobutyric acid receptor (GABA-A) is the most common receptor of fast synaptic inhibition in the human brain. Gamma protein encoded by the GABRG2 gene is one of the subunits of the GABA-A receptor, which plays an essential role in the function of this receptor. Several studies have identified various febrile seizure (FS) and epilepsy risk variants of GABRG2 gene in different populations, but some others did not support these results. The aim of this case-control study is to investigate whether GABRG2 polymorphisms contribute to susceptibility for FS and epilepsy in pooled data of three cohorts, from Malaysia (composed of Malay, Chinese, and Indian), Hong Kong, and Korea. Furthermore, the pooled dataset of these cohorts with previous reports were meta-analyzed for determining the risk effect size of the rs211037 polymorphism on FS and symptomatic epilepsy (SE). The rs211037, rs210987, rs440218, rs2422106, rs211014, and rs401750 polymorphisms were genotyped in the 6442 subjects (1729 epilepsy and 4713 controls). Results of the case-control study showed associations between rs211037 and the risk of SE in the pooled data from all cohorts (T vs. C, p = 3 × 10(-5), and TT vs. CC, p = 2 × 10(-5)) and the risk of partial seizure in the combined data of Malaysia and Hong Kong (both T vs. C and TT vs. CC, p = 2 × 10(-6)). The rs211037-rs210987 and rs2422106-rs211014-rs401750 haplotypes were also associated with susceptibility to SE in Chinese. Meta-analysis of all Asians identified association between rs211037 and FS and SE (T vs. C, p = 4 × 10(-4), and p = 4 × 10(-3), respectively). In conclusion, rs211037 alone may be a risk factor for FS, partial seizure, and SE, and in linkage disequilibrium with rs210987 can contribute to FS and SE in Asians, particularly in Chinese.
  6. Haerian BS, Sha'ari HM, Fong CY, Tan HJ, Wong SW, Ong LC, et al.
    J Neuroimmunol, 2015 Jan 15;278:137-43.
    PMID: 25595263 DOI: 10.1016/j.jneuroim.2014.12.016
    Neuroinflammation can damage the brain and plays a critical role in the pathophysiology of epilepsy. Tissue inhibitor of metalloproteinase 4 (TIMP4) is an inflammation-induced apoptosis and matrix turnover factor involved in several neuronal disorders and inflammatory diseases. Evidence has shown linkage disequilibrium between rs3755724 (-55C/T) of this gene with synapsin 2 (SYN2) rs3773364 and peroxisome proliferator-activated G receptor (PPARG) rs2920502 loci, which contribute to epilepsy in Caucasians. The aim of this study was to examine the association of these loci alone or their haplotypes with the risk of epilepsy in the Malaysian population. Genomic DNA of 1241 Malaysian Chinese, Indian, and Malay subjects (670 patients with epilepsy and 571 healthy individuals) was genotyped for the candidate loci by using the Sequenom MassArray method. Allele and genotype association of rs3755724 with susceptibility to epilepsy was significant in the Malaysian Chinese with focal epilepsy under codominant and dominant models (C vs. T: 1.5 (1.1-2.0), p=0.02; CT vs. TT: 1.8 (1.2-2.8), p=0.007 and 1.8 (1.2-2.7), p=0.006, respectively). The T allele and the TT genotype were more common in patients than in controls. No significant association was found between rs2920502 and rs3773364-rs3755724-rs2920502 haplotypes for susceptibility to epilepsy in each ethnicity. This study provides evidence that the promoter TIMP4 rs3755724 is a new focal epilepsy susceptibility variant that is plausibly involved in inflammation-induced seizures in Malaysian Chinese.
  7. Haerian BS, Baum L, Kwan P, Tan HJ, Raymond AA, Mohamed Z
    Pharmacogenomics, 2013 Jul;14(10):1153-66.
    PMID: 23859570 DOI: 10.2217/pgs.13.104
    Aim: Approximately a third of newly diagnosed epilepsy patients do not respond to antiepileptic drugs (AEDs). Evidence suggests that low penetrance variants in the genes of drug targets such as voltage-gated sodium channels may be involved in drug responsiveness. To examine this hypothesis, we compared data from two epilepsy cohorts from Malaysia and Hong Kong, as well as a meta-analysis from published data.

    Materials & methods: Genotype analysis of 39 polymorphisms located in the SCN1A, SCN2A and SCN3A genes was performed on 1504 epilepsy patients from Malaysia and Hong Kong who were receiving AEDs. Meta-analysis was performed for pooled data of SCN1A rs3812718 and rs2298771, and SCN2A rs17183814 polymorphisms.

    Results: Our data from the Hong Kong and Malaysia cohorts showed no significant allele, genotype and haplotype association of polymorphisms in the SCN1A, SCN2A, and SCN3A genes with drug responsiveness in epilepsy. This finding was supported by a meta-analysis for SCN1A rs3812718 and rs2298771, and for SCN2A rs17183814 polymorphisms.

    Conclusion: Our comprehensive study suggests that common polymorphisms in SCN1A, SCN2A and SCN3A do not play major roles in influencing response to AEDs.
  8. Haghvirdizadeh P, Mohamed Z, Abdullah NA, Haghvirdizadeh P, Haerian MS, Haerian BS
    J Diabetes Res, 2015;2015:908152.
    PMID: 26448950 DOI: 10.1155/2015/908152
    Diabetes mellitus (DM) is a major worldwide health problem and its prevalence has been rapidly increasing in the last century. It is caused by defects in insulin secretion or insulin action or both, leading to hyperglycemia. Of the various types of DM, type 2 occurs most frequently. Multiple genes and their interactions are involved in the insulin secretion pathway. Insulin secretion is mediated through the ATP-sensitive potassium (KATP) channel in pancreatic beta cells. This channel is a heteromeric protein, composed of four inward-rectifier potassium ion channel (Kir6.2) tetramers, which form the pore of the KATP channel, as well as sulfonylurea receptor 1 subunits surrounding the pore. Kir6.2 is encoded by the potassium inwardly rectifying channel, subfamily J, member 11 (KCNJ11) gene, a member of the potassium channel genes. Numerous studies have reported the involvement of single nucleotide polymorphisms of the KCNJ11 gene and their interactions in the susceptibility to DM. This review discusses the current evidence for the contribution of common KCNJ11 genetic variants to the development of DM. Future studies should concentrate on understanding the exact role played by these risk variants in the development of DM.
  9. Hajissa K, Zakaria R, Suppian R, Mohamed Z
    Parasit Vectors, 2015;8:315.
    PMID: 26062975 DOI: 10.1186/s13071-015-0932-0
    Serological investigation remains the primary approach to achieve satisfactory results in Toxoplasma gondii identification. However, the accuracy of the native antigen used in the current diagnostic kits has proven to be insufficient as well as difficult to standardize, so significant efforts have been made to find alternative reagents as capture antigens. Consequently, multi-epitope peptides are promising diagnostic markers, with the potential for improving the accuracy of diagnostic kits. In this study, we described a simple, inexpensive and improved strategy to acquire such diagnostic markers. The study was aimed at producing novel synthetic protein consisting of multiple immunodominant epitopes of several T. gondii antigens.
  10. Hajissa K, Zakaria R, Suppian R, Mohamed Z
    J Adv Vet Anim Res, 2019 Jun;6(2):174-182.
    PMID: 31453188 DOI: 10.5455/javar.2019.f329
    Despite the significant progress in the recent efforts toward developing an effective vaccine against toxoplasmosis, the search for new protective vaccination strategy still remains a challenge and elusive goal because it becomes the appropriate way to prevent the disease. Various experimental approaches in the past few years showed that developing a potential vaccine against the disease can be achievable. The combination of multi-epitopes expressing different stages of the parasite life cycle has become an optimal strategy for acquiring a potent, safe, and effective vaccine. Epitope-based vaccines have gained attention as alternative vaccine candidates due to their ability of inducing protective immune responses. This mini-review highlights the current status and the prospects of Toxoplasma gondii vaccine development along with the application of epitope-based vaccine in the future parasite immunization as a novel under development and evaluation strategy.
  11. Hajissa K, Zakaria R, Suppian R, Mohamed Z
    Iran J Parasitol, 2018 8 3;13(2):215-224.
    PMID: 30069205
    Background: Toxoplasma gondii is a widely prevalent intracellular protozoan parasite which causes serious clinical and veterinary problems. Development of an effective vaccine for controlling toxoplasmosis is an extremely important aim. In the present study, the protective efficacy of recombinant multiepitope antigen (USM.TOXO1) expressing nine potential epitopes identified from SAG1, GRA2, and GRA7 of Toxoplasma gondii was evaluated in BALB/c mice.

    Methods: Mice were immunized subcutaneously with three doses of USM.TOXO1 antigen (10 μg/ml). Following the immunization, the IgG antibody, IgG subclass, IFN-γ and IL-4 production were evaluated using ELISA, the study was conducted at Animal Research and Service Center (ARASC), USM Health Campus in 2016.

    Results: Mice immunized with USM.TOXO1 significantly induced a mixed Th1/Th2 response polarized toward the IgG1 antibody isotype. While the cytokine analysis revealed a significant release of IFN-γ cytokines.

    Conclusion: USM.TOXO1 is a potential vaccine candidate that elicits strong immunity in BALB/c mice. The proven immunogenicity of the generated antigen can serve as a premise for further use of epitope-based vaccine in the immunoprevention of human and animal toxoplasmosis.

  12. Hajissa K, Muhajir AEMA, Eshag HA, Alfadel A, Nahied E, Dahab R, et al.
    BMC Res Notes, 2018 Oct 31;11(1):779.
    PMID: 30382901 DOI: 10.1186/s13104-018-3871-y
    OBJECTIVE: Schistosomiasis remains one of the most common parasitic diseases worldwide. This is a cross-sectional study aimed to determine the prevalence of schistosomiasis and its associated risk factors among primary school children in Um-Asher area. The study was conducted among 170 primary school students in Um-Asher area from November 2017 to February 2018. Urine and stool samples were collected and examined for schistosomiasis infections. Moreover, data on sociodemographic characteristics and associated risk factors were obtained using a questionnaire.

    RESULTS: The overall prevalence of Schistosoma haematobium was 12.9%, whereas that of Schistosoma mansoni was 2.95%. Additionally, the males had higher prevalence (60%) of S. mansoni than females (40%). However, both gender were equally infected with S. haematobium (50%). With regard to risk factors, distance of residence from water source and source of drinking water are relatively associated with the infection.

  13. Hajissa K, Islam MA, Sanyang AM, Mohamed Z
    PLoS Negl Trop Dis, 2022 Feb 11;16(2):e0009971.
    PMID: 35148325 DOI: 10.1371/journal.pntd.0009971
    INTRODUCTION: Parasitic infections, especially intestinal protozoan parasites (IPPs) remain a significant public health issue in Africa, where many conditions favour the transmission and children are the primary victims. This systematic review and meta-analysis was carried out with the objective of assessing the prevalence of IPPs among school children in Africa.

    METHODS: Relevant studies published between January 2000 and December 2020 were identified by systematic online search on PubMed, Web of Science, Embase and Scopus databases without language restriction. Pooled prevalence was estimated using a random-effects model. Heterogeneity of studies were assessed using Cochrane Q test and I2 test, while publication bias was evaluated using Egger's test.

    RESULTS: Of the 1,645 articles identified through our searches, 46 cross-sectional studies matched our inclusion criteria, reported data from 29,968 school children of Africa. The pooled prevalence of intestinal protozoan parasites amongst African school children was 25.8% (95% CI: 21.2%-30.3%) with E. histolytica/ dispar (13.3%; 95% CI: 10.9%-15.9%) and Giardia spp. (12%; 95% CI: 9.8%-14.3%) were the most predominant pathogenic parasites amongst the study participants. While E. coli was the most common non-pathogenic protozoa (17.1%; 95% CI: 10.9%-23.2%).

    CONCLUSIONS: This study revealed a relatively high prevalence of IPPs in school children, especially in northern and western Africa. Thus, poverty reduction, improvement of sanitation and hygiene and attention to preventive control measures will be the key to reducing protozoan parasite transmission.

  14. Hajissa K, Zakaria R, Suppian R, Mohamed Z
    BMC Infect Dis, 2017 12 29;17(1):807.
    PMID: 29284420 DOI: 10.1186/s12879-017-2920-9
    BACKGROUND: The inefficiency of the current tachyzoite antigen-based serological assays for the serodiagnosis of Toxoplasma gondii infection mandates the need for acquirement of reliable and standard diagnostic reagents. Recently, epitope-based antigens have emerged as an alternative diagnostic marker for the achievement of highly sensitive and specific capture antigens. In this study, the diagnostic utility of a recombinant multiepitope antigen (USM.TOXO1) for the serodiagnosis of human toxoplasmosis was evaluated.

    METHODS: An indirect enzyme-linked immunosorbent assay (ELISA) was developed to evaluate the usefulness of USM.TOXO1 antigen for the detection of IgG antibodies against Toxoplasma gondii in human sera. Whereas the reactivity of the developed antigen against IgM antibody was evaluated by western blot and Dot enzyme immunoassay (dot-EIA) analysis.

    RESULTS: The diagnostic performance of the new antigens in IgG ELISA was achieved at the maximum values of 85.43% and 81.25% for diagnostic sensitivity and specificity respectively. The USM.TOXO1 was also proven to be reactive with anti- T. gondii IgM antibody.

    CONCLUSIONS: This finding makes the USM.TOXO1 antigen an attractive candidate for improving the toxoplasmosis serodiagnosis and demonstrates that multiepitope antigens could be a potential and promising diagnostic marker for the development of high sensitive and accurate assays.

  15. Halim-Fikri H, Etemad A, Abdul Latif AZ, Merican AF, Baig AA, Annuar AA, et al.
    BMC Res Notes, 2015;8:176.
    PMID: 25925844 DOI: 10.1186/s13104-015-1123-y
    The Malaysian Node of the Human Variome Project (MyHVP) is one of the eighteen official Human Variome Project (HVP) country-specific nodes. Since its inception in 9(th) October 2010, MyHVP has attracted the significant number of Malaysian clinicians and researchers to participate and contribute their data to this project. MyHVP also act as the center of coordination for genotypic and phenotypic variation studies of the Malaysian population. A specialized database was developed to store and manage the data based on genetic variations which also associated with health and disease of Malaysian ethnic groups. This ethnic-specific database is called the Malaysian Node of the Human Variome Project database (MyHVPDb).
  16. Halizan MZM, Mohamed Z, Yahya AK
    Sci Rep, 2021 May 07;11(1):9744.
    PMID: 33963258 DOI: 10.1038/s41598-021-89132-4
    In electronic applications, good dielectric permittivity material has huge potential in the capacitive energy storage devices. Herein, in the present work the dielectric study of SrLaLiTe1-xMnxO6 (x = 0.02, 0.04, 0.06, 0.08, and 0.10) double perovskites has been studied and discussed. These compounds were prepared through solid-state reaction method. All of the prepared compounds were confirmed to crystallized in monoclinic structure of P21/n space symmetry with better crystallization when dopant concentrations increased until x = 0.08. The formation of Li-O-Te/Mn bonds in octahedral structures in all compounds were confirmed in this study. The existence of peaks at specific wavenumbers indicated vibrations of B-site cations' bonds. When dopant amounts were increased from x = 0.02 to x = 0.08, there was an increasing trend of grains sizes formation in the compounds. The discussions on effects of grain sizes towards dielectric properties were included in this paper. Other important results and discussions comprised of the significant effects of dopant on the optical band gap (Eopt) and absorption frequencies of the compounds. The decreasing trend of Eopt towards semiconductor range indicated the compounds' promising potentials for optoelectronic device application.
  17. Hamidah NH, Azma RZ, Ezalia E, Das S, Umar NA, Swaminathan M, et al.
    Clin Ter, 2010;161(5):445-8.
    PMID: 20949241
    Non-secretory multiple myeloma (NSMM) is a rare variant of the classic form of multiple myeloma (MM). In NSMM, no monoclonal gammopathy can be detected in serum or urine by conventional techniques, making the diagnosis more difficult. We describe a 71-year-old man who had been diagnosed and treated for granulocytic sarcoma one year prior to his recent problems of progressive low-back pain of two months duration. Skeletal X-rays showed diffuse osteolytic lesions with multiple pathological fractures but there was no monoclonal gammopathy in the serum or urine. The biopsy of the lytic lesion on the upper part of the femur showed infiltration by abnormal plasma cells. A diagnosis of NSMM was made and he was treated with chemotherapy. The early diagnostic difficulty and the challenges faced regarding the case are discussed.
  18. Harith AA, Mohamed Z, Mohammad A, Lim KK, Reffin N, Mohd Fadzil M, et al.
    Med J Malaysia, 2023 Sep;78(5):653-660.
    PMID: 37775494
    INTRODUCTION: Healthcare drivers, including ambulance drivers, were less concerned about health and safety during the COVID-19 pandemic, with not only the risk of COVID-19 infection but also a higher risk of prolonged states of alertness, stress, burnout, fatigue and road traffic accident. This study aimed to determine the prevalence of stress and its associated factors among healthcare drivers, especially during the COVID-19 pandemic.

    MATERIALS AND METHODS: This study employs a crosssectional study design and utilises self-reported data obtained from locally validated personal stress inventory questionnaires. The data collection period spanned from August 1 to 31, 2020. The study sample consisted of 163 healthcare drivers affiliated with the Negeri Sembilan State Health Department. The Chi-square test and Fisher's exact test were the first used to determine the association between variables prior to conducting multiple logistic regression to predict the relationship between dependent and independent variables.

    RESULTS: In COVID-19's first year, 7.4% (n = 12) of healthcare drivers reported perceived stress with ambulance drivers reporting more stress (10.6%; n = 5) than non-ambulance drivers (6.0%; n = 7). Simple statistical analysis identified perceived stress significantly associated with household income, smoking status and performing on-call. Further analysis by multiple logistic regression found that perceived stress was significantly related to smoking (aOR 19.9, 95% CI: 1.86-213.90), and performing on-call (aOR 8.69, 95% CI 1.21-62.28). Nevertheless, no association was found between perceived stress and age, ethnicity, marital status, education, household income, co-morbidities, driving assignment, employment duration, needing a part-time job or motor vehicle accident history.

    CONCLUSION: The study found that the perceived stress amongst Malaysian healthcare drivers during the COVID-19 pandemic was relatively low. This could be due to fewer lifethreatening tasks, emergencies, assigned tasks and increase income due to overtime during the COVD-19 pandemic. The OSH team's efforts to provide consistent safety and health training, including stress management, may have contributed to the healthcare driver's ability to effectively manage the stressful circumstances encountered during the pandemic. In order to enhance salary competitiveness, employers should provide financial management education alongside subsidised housing and childcare provisions. Healthcare drivers who smoke should be taught different stress reduction techniques so that they can handle their stress in a healthy way.

  19. Haron DE, Chik Z, Noordin MI, Mohamed Z
    Iran J Basic Med Sci, 2015 Dec;18(12):1167-75.
    PMID: 26877845
    Transdermal preparations for testosterone are becoming popular because of their unique advantages such as avoidance of first-pass effect, convenience, improved bioavailability, and reduction of systemic side effects. A novel testosterone transdermal delivery system (TDDS) was developed using a palm oil base called HAMIN™ (a commercial product) and tested using in vitro and in vivo skin permeability test methods.
  20. Haruna A, Mohamed Z, Efe MÖ, Basri MAM
    ISA Trans, 2020 Feb;97:1-13.
    PMID: 31327468 DOI: 10.1016/j.isatra.2019.07.016
    This paper proposes an improved method of integral backstepping for real time control of a laboratory helicopter with variable speed rotors known as the Two-Rotor Aero-dynamic System (TRAS). The coupled system is decomposed into the horizontal subsystem (HS) and the vertical subsystem (VS) and traditional backstepping, augmented with direct integral action is designed for each subsystem. The transient response to both constant and time varying references is then simultaneously improved by modifying an already proposed method called dual boundary conditional integration. A switching technique is also employed to enhance the tracking response of the undamped HS for its bi-directional motor which exhibits jerking effects. Experimental results show that the proposed approach yields improved transient and tracking performance when compared to previously proposed methods exploiting conditional integration earlier proposed for improving the transient response of controlled nonlinear systems with integral action. The results also show the robustness of the proposed method in the presence of the coupling effects and additional external disturbance applied to the system in the form of a wind gust.
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