Browse publications by year: 2018

  1. Alam J, Jantan I, Kumolosasi E, Nafiah MA, Mesaik MA
    Curr Pharm Biotechnol, 2018;19(14):1156-1169.
    PMID: 30539691 DOI: 10.2174/1389201020666181211124954
    BACKGROUND: Standardized extract of Phyllanthus amarus has been shown to possess inhibitory effects on cellular and humoral immune responses in Wistar-Kyoto rats and Balb/c mice.

    OBJECTIVE: In the present study, the standardized extract of P. amarus was investigated for its suppressive effects on type II collagen-induced rheumatoid arthritis (TCIA) in Sprague Dawley rats.

    METHOD: The major components of the extracts, lignans and phenolic compounds were analysed by using a validated reversed phase HPLC and LC-MS/MS. A rheumatoid arthritis rat model was induced by administering a bovine type II collagen emulsion subcutaneously at the base of tail, on day 0 and 7 of the experiment. Effects of the extract on severity assessment, changes in the hind paw volume, bone mineral density, body weight and body temperature were measured. Concentrations of cytokines (TNF-α, IL-1β, IL-1α, IL-6) released, matrix metalloproteinases (MMP-1, MMP-3 MMP-9) and their inhibitor (TIMP-1), haematological and biochemical changes were also measured. ELISA was used to measure the cytokines and proteinases in the rat serum and synovial fluid according to manufacturer's instructions.

    RESULTS: The extract dose-dependently modulated the progression in physical parameters (i.e. decrease in body weight, increase in body temperature, reduced hind paw volume, reduced the severity of arthritis), bone mineral density, haematological and biochemical perturbations, serum cytokines production and levels of matrix metalloproteinases and their inhibitor in the synovial fluid. Histopathological examination of the knee joint also revealed that the extract effectively reduced synovitis, pannus formation, bone resorption and cartilage destruction.

    CONCLUSION: The results suggest that the oral administration of a standardized extract of P. amarus was able to suppress the humoral and cellular immune responses to type II collagen, resulting in the reduction of the development of TCIA in the rats.

    MeSH terms: Animals; Arthritis, Experimental/drug therapy*; Arthritis, Experimental/immunology; Immunity, Cellular/drug effects; Organization and Administration; Plant Extracts/isolation & purification; Plant Extracts/therapeutic use*; Cytokines/metabolism; Rats, Sprague-Dawley; Antirheumatic Agents/isolation & purification; Antirheumatic Agents/therapeutic use*; Matrix Metalloproteinases/metabolism; Collagen Type II; Phyllanthus/chemistry*; Rats; Immunity, Humoral/drug effects
  2. Malik IA, Durairajanayagam D, Singh HJ
    Asian J Androl, 2018 12 13;21(3):296-299.
    PMID: 30539926 DOI: 10.4103/aja.aja_98_18
    Leptin, an adipocyte-derived hormone, serves numerous physiological functions in the body, particularly during puberty and reproduction. The exact mechanism by which leptin activates the gonadotropin-releasing hormone (GnRH) neurons to trigger puberty and reproduction remains unclear. Given the widespread distribution of leptin receptors in the body, both central and peripheral mechanisms involving the hypothalamic-pituitary-gonadal axis have been hypothesized. Leptin is necessary for normal reproductive function, but when present in excess, it can have detrimental effects on the male reproductive system. Human and animal studies point to leptin as a link between infertility and obesity, a suggestion that is corroborated by findings of low sperm count, increased sperm abnormalities, oxidative stress, and increased leptin levels in obese men. In addition, daily leptin administration to normal-weight rats has been shown to result in similar abnormalities in sperm parameters. The major pathways causing these abnormalities remain unidentified; however, these adverse effects have been attributed to leptin-induced increased oxidative stress because they are prevented by concurrently administering melatonin. Studies on leptin and its impact on sperm function are highly relevant in understanding and managing male infertility, particularly in overweight and obese men.
    MeSH terms: Animals; Humans; Infertility, Male/etiology; Infertility, Male/physiopathology*; Male; Obesity/complications; Reproduction/physiology*; Leptin/physiology*; Overweight/complications
  3. Lee SH, Atiya N, Wang SM, Manikam R, Raju CS, Sekaran SD
    Intervirology, 2018;61(4):193-203.
    PMID: 30541013 DOI: 10.1159/000495180
    OBJECTIVE: Herpes simplex virus infection through the neuronal route is the most well-studied mode of viral encephalitis that can persists in a human host for a lifetime. However, the involvement of other possible infection mechanisms by the virus remains underexplored. Therefore, this study aims to determine the temporal effects and mechanisms by which the virus breaches the human brain micro-vascular endothelial cells of the blood-brain barrier.

    METHOD: An electrical cell-substrate impedance-sensing tool was utilized to study the real-time cell-cell barrier or morphological changes in response to the virus infection.

    RESULTS: Herpes simplex virus, regardless of type (i.e., 1 or 2), reduced the cell-cell barrier resistance almost immediately after virus addition to endothelial cells, with negligible involvement of cell-matrix adhesion changes. There is no exclusivity in the infection ability of endothelial cells. From 30 h after HSV infection, there was an increase in cell membrane capacitance with a subsequent loss of cell-matrix adhesion capability, indicating a viability loss of the infected endothelial cells.

    CONCLUSION: This study shows for the first time that destruction of human brain micro-vascular endothelial cells as an in vitro model of the blood-brain barrier could be an alternative invasion mechanism during herpes simplex virus infection.

    MeSH terms: Blood-Brain Barrier/physiology*; Blood-Brain Barrier/virology*; Cell Survival; Humans; Models, Biological; Electric Impedance; Simplexvirus/growth & development*; Endothelial Cells/physiology*; Endothelial Cells/virology*
  4. Masello JF, Martínez J, Calderón L, Wink M, Quillfeldt P, Sanz V, et al.
    Parasit Vectors, 2018 Jun 19;11(1):357.
    PMID: 29921331 DOI: 10.1186/s13071-018-2940-3
    BACKGROUND: Parasites can exert selection pressure on their hosts through effects on survival, on reproductive success, on sexually selected ornament, with important ecological and evolutionary consequences, such as changes in population viability. Consequently, hemoparasites have become the focus of recent avian studies. Infection varies significantly among taxa. Various factors might explain the differences in infection among taxa, including habitat, climate, host density, the presence of vectors, life history and immune defence. Feeding behaviour can also be relevant both through increased exposure to vectors and consumption of secondary metabolites with preventative or therapeutic effects that can reduce parasite load. However, the latter has been little investigated. Psittaciformes (parrots and cockatoos) are a good model to investigate these topics, as they are known to use biological control against ectoparasites and to feed on toxic food. We investigated the presence of avian malaria parasites (Plasmodium), intracellular haemosporidians (Haemoproteus, Leucocytozoon), unicellular flagellate protozoans (Trypanosoma) and microfilariae in 19 Psittaciformes species from a range of habitats in the Indo-Malayan, Australasian and Neotropical regions. We gathered additional data on hemoparasites in wild Psittaciformes from the literature. We considered factors that may control the presence of hemoparasites in the Psittaciformes, compiling information on diet, habitat, and climate. Furthermore, we investigated the role of diet in providing antiparasitic secondary metabolites that could be used as self-medication to reduce parasite load.

    RESULTS: We found hemoparasites in only two of 19 species sampled. Among them, all species that consume at least one food item known for its secondary metabolites with antimalarial, trypanocidal or general antiparasitic properties, were free from hemoparasites. In contrast, the infected parrots do not consume food items with antimalarial or even general antiparasitic properties. We found that the two infected species in this study consumed omnivorous diets. When we combined our data with data from studies previously investigating blood parasites in wild parrots, the positive relationship between omnivorous diets and hemoparasite infestation was confirmed. Individuals from open habitats were less infected than those from forests.

    CONCLUSIONS: The consumption of food items known for their secondary metabolites with antimalarial, trypanocidal or general antiparasitic properties, as well as the higher proportion of infected species among omnivorous parrots, could explain the low prevalence of hemoparasites reported in many vertebrates.

    MeSH terms: Animals; Animal Feed/analysis*; Animals, Wild/blood; Animals, Wild/metabolism; Animals, Wild/parasitology; Antiparasitic Agents/analysis; Antiparasitic Agents/metabolism*; Bird Diseases/metabolism*; Bird Diseases/epidemiology; Bird Diseases/parasitology; Bird Diseases/prevention & control*; Climate; Female; Malaysia/epidemiology; Male; Plasmodium/genetics; Plasmodium/isolation & purification; Plasmodium/physiology; Psittaciformes/blood; Psittaciformes/classification; Psittaciformes/metabolism; Psittaciformes/parasitology*; Prevalence; Haemosporida/genetics; Haemosporida/isolation & purification; Haemosporida/physiology; Ecosystem; Australasia/epidemiology; Secondary Metabolism
  5. Lim CW, Cheng J, Tay ELT, Teo HY, Wong EPY, Yong VKY, et al.
    BMC Ophthalmol, 2018 Dec 10;18(1):315.
    PMID: 30526537 DOI: 10.1186/s12886-018-0976-y
    BACKGROUND: Despite the potential usefulness of optical coherence tomography angiography in retinal and optic disc conditions, the reliability of the imaging modality remains unclear. This study set out to measure the microvascular density of macula and optic disc by mean of optical coherence tomography angiography and report the repeatability of the vessel density measurements.

    METHODS: Cross sectional observational cohort study. Subjects with normal eyes were recruited. Two sets of optical coherence tomography angiography images of macula and optic nerve head were acquired during one visit. Novel in-house developed software was used to count the pixels in each images and to compute the microvessel density of the macula and optic disc. Data were analysed to determine the measurement repeatability.

    RESULTS: A total of 176 eyes from 88 consecutive normal subjects were recruited. For macular images, the mean vessel density at superficial retina, deep retina, outer retina and choriocapillaries segment was OD 0.113 and OS 0.111, OD 0.239 and OS 0.230, OD 0.179 and OS 0.164, OD 0.237 and OS 0.215 respectively. For optic disc images, mean vessel density at vitreoretinal interface, radial peripapillary capillary, superficial nerve head and disc segment at the level of choroid were OD 0.084 and OS 0.085, OD 0.140 and OS 0.138, OD 0.216 and OS 0.209, OD 0.227 and OS 0.236 respectively. The measurement repeatability tests showed that the coefficient of variation of macular scans, for right and left eyes, ranged from 6.4 to 31.1% and 5.3 to 59.4%. Likewise, the coefficient of variation of optic disc scans, for right and left eyes, ranged from 14.3 to 77.4% and 13.5 to 75.3%.

    CONCLUSIONS: Optical coherence tomography angiography is a useful modality to visualise the microvasculature plexus of macula and optic nerve head. The vessel density measurement of macular scan by mean of optical coherence tomography angiography demonstrated good repeatability. The optic disc scan, on the other hand, showed a higher coefficient of variation indicating a lower measurement repeatability than macular scan. Interpretation of optical coherence tomography angiography should take into account test-retest repeatability of the imaging system.

    TRIAL REGISTRATION: National Healthcare Group Domain Specific Review Board ( NHG DSRB ) Singapore. DSRB Reference: 2015/00301.

    MeSH terms: Adult; Cross-Sectional Studies; Female; Fluorescein Angiography/methods; Humans; Macula Lutea/blood supply*; Male; Middle Aged; Optic Disk/blood supply*; Retinal Vessels/cytology*; Reproducibility of Results; Tomography, Optical Coherence/methods
  6. Grigg MJ, William T, Piera KA, Rajahram GS, Jelip J, Aziz A, et al.
    Malar J, 2018 Dec 10;17(1):463.
    PMID: 30526613 DOI: 10.1186/s12936-018-2593-x
    BACKGROUND: Spreading Plasmodium falciparum artemisinin drug resistance threatens global malaria public health gains. Limited data exist to define the extent of P. falciparum artemisinin resistance southeast of the Greater Mekong region in Malaysia.

    METHODS: A clinical efficacy study of oral artesunate (total target dose 12 mg/kg) daily for 3 days was conducted in patients with uncomplicated falciparum malaria and a parasite count 

    MeSH terms: Adolescent; Adult; Antimalarials/pharmacology*; Antimalarials/therapeutic use; Child; Child, Preschool; Drug Resistance*; Female; Genetic Markers/genetics; Humans; Malaysia/epidemiology; Male; Middle Aged; Protozoan Proteins/genetics; Treatment Outcome; Molecular Epidemiology; Artemisinins/pharmacology*; Artemisinins/therapeutic use; Young Adult; Parasite Load
  7. Wu YL, Lee V, Liam CK, Lu S, Park K, Srimuninnimit V, et al.
    Lung Cancer, 2018 12;126:1-8.
    PMID: 30527172 DOI: 10.1016/j.lungcan.2018.10.004
    OBJECTIVE: Patients with advanced non-small-cell lung cancer (NSCLC) with an adenocarcinoma component are recommended to undergo epidermal growth factor receptor (EGFR) mutation testing when being considered for EGFR targeted therapy. We conducted an exploratory analysis to inform the clinical utility of EGFR mutation testing in blood cell-free DNA using the cobas®EGFR Mutation Test v2.

    MATERIALS AND METHODS: Two EGFR mutation tests, a tissue-based assay (cobas® v1) and a tissue- and blood-based assay (cobas® v2) were used to analyze matched biopsy and blood samples (897 paired samples) from three Asian studies of first-line erlotinib with similar intent-to-treat populations. ENSURE was a phase III comparison of erlotinib and gemcitabine/platinum, FASTACT-2 was a phase III study of gemcitabine/platinum plus erlotinib or placebo, and ASPIRATION was a single-arm phase II study of erlotinib. Agreement statistics were evaluated, based on sensitivity and specificity between the two assays in subgroups of patients with increasing tumor burden.

    RESULTS: Patients with discordant EGFR (tissue+/plasma-) mutation status achieved longer progression-free and overall survival than those with concordant (tissue+/plasma+) mutation status. Tumor burden was significantly greater in patients with concordant versus discordant mutations. Pooled analyses of data from the three studies showed a sensitivity of 72.1% (95% confidence interval [CI] 67.8-76.1) and a specificity of 97.9% (95% CI 96.0-99.0) for blood-based testing; sensitivity was greatest in patients with larger baseline tumors.

    CONCLUSIONS: Blood-based EGFR mutation testing demonstrated high specificity and good sensitivity, and offers a convenient and easily accessible diagnostic method to complement tissue-based tests. Patients with a discordant mutation status in plasma and tissue, had improved survival outcomes compared with those with a concordant mutation status, which may be due to their lower tumor burden. These data help to inform the clinical utility of this blood-based assay for the detection of EGFR mutations.

    MeSH terms: Erlotinib Hydrochloride/administration & dosage; Antineoplastic Combined Chemotherapy Protocols/therapeutic use*; Carcinoma, Non-Small-Cell Lung/drug therapy*; Carcinoma, Non-Small-Cell Lung/genetics; Carcinoma, Non-Small-Cell Lung/pathology; Cisplatin/administration & dosage; Deoxycytidine/administration & dosage; Deoxycytidine/analogs & derivatives; DNA Mutational Analysis/methods; Humans; Lung Neoplasms/blood; Lung Neoplasms/drug therapy*; Lung Neoplasms/genetics; Mutation*; Multicenter Studies as Topic; Randomized Controlled Trials as Topic; Carboplatin/administration & dosage; Clinical Trials, Phase II as Topic; Clinical Trials, Phase III as Topic; Protein Kinase Inhibitors/administration & dosage; Kaplan-Meier Estimate; ErbB Receptors/antagonists & inhibitors; ErbB Receptors/genetics; ErbB Receptors/metabolism
  8. Kuruvilla S, Hinton R, Boerma T, Bunney R, Casamitjana N, Cortez R, et al.
    BMJ, 2018 Dec 07;363:k4771.
    PMID: 30530519 DOI: 10.1136/bmj.k4771
    Shyama Kuruvilla and colleagues present findings across 12 country case studies of multisectoral collaboration, showing how diverse sectors intentionally shape new ways of collaborating and learning, using “business not as usual” strategies to transform situations and achieve shared goals
    MeSH terms: Commerce; Delivery of Health Care/methods*; Health Promotion/methods*; Health Promotion/organization & administration; Humans; Models, Theoretical; Intersectoral Collaboration*
  9. Buang SN, Ja'afar S, Pathmanathan I, Saint V
    BMJ, 2018 Dec 07;363:k4602.
    PMID: 30530626 DOI: 10.1136/bmj.k4602
    MeSH terms: Adolescent; Uterine Cervical Neoplasms/prevention & control; Cooperative Behavior; Female; Government; Humans; Malaysia; Preventive Health Services/methods*; Vaccination*; Papillomavirus Infections/prevention & control*; Papillomavirus Vaccines*; Public-Private Sector Partnerships
  10. Behzadnia A, Smith DR, Goodson ML
    Educ Health (Abingdon), 2018 12 12;31(2):80-86.
    PMID: 30531049 DOI: 10.4103/efh.EfH_280_17
    Background: Learning approaches have been proposed to affect the experience of psychological stress among tertiary students in recent years. This relationship becomes important in stressful environments such as medical schools. However, the relationship between stress and learning approaches is not well understood, and often studies done cannot be generalized due to different sociocultural differences. In particular, no study in Malaysia has looked at learning approaches among medical students.

    Aims: To address this gap, we examined the relationship between perceived stress and learning approaches by considering sources of stress.

    Methodology: The Perceived Stress Scale (PSS-10), Medical Student Stressor Questionnaire, and the Revised Two-Factor Study Process Questionnaire were answered by the preclinical and final-year students studying MBBS in a Malaysian campus of British University.

    Results: Deep learning was positively and surface learning negatively associated with perception of coping with stress. In this study, neither approaches were associated with psychological stress as opposed to previous reports. We found surface learners to report higher level of stress associated with social stressors. We found students' self-perception of feeling incompetent and feeling they need to do well to be significant sources of stress.

    Discussion: Deep learning promotes psychological resilience. This is of paramount importance in learning environments where stress is highly prevalent such as medical school. Promotion of deep learning among medical students is required at earlier stages as they tend to solidify their approach through their university years and carry that approach beyond school into their workplace.
    MeSH terms: Adaptation, Psychological; Adolescent; Cross-Sectional Studies; Education, Medical, Undergraduate; Female; Humans; Learning*; Malaysia; Male; Stress, Psychological/psychology*; Students, Medical/psychology*; Young Adult
  11. Narhari P, Haseeb A, Lee S, Singh VA
    Indian J Orthop, 2018 12 12;52(6):682-683.
    PMID: 30532313 DOI: 10.4103/ortho.IJOrtho_141_18
  12. Rahimi SN, Kassim MZ, Shamsul Anuar SA, Ab Ghani SM, Baharuddin IH, Lim TW
    J Indian Prosthodont Soc, 2018 Oct;18(Suppl 1):S11-S12.
    PMID: 30532402 DOI: 10.4103/0972-4052.244600
External Links