Displaying publications 61 - 80 of 1460 in total

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  1. Boo NY
    Ann Acad Med Singap, 2008 Dec;37(12 Suppl):60-3.
    PMID: 19904452
    Auditory neuropathy is defined by the presence of normal evoked otoacoustic emissions (OAE) and absent or abnormal auditory brainstem responses (ABR). The sites of lesion could be at the cochlear inner hair cells, spiral ganglion cells of the cochlea, synapse between the inner hair cells and auditory nerve, or the auditory nerve itself. Genetic, infectious or neonatal/perinatal insults are the 3 most commonly identified underlying causes. Children usually present with delay in speech and language development while adult patients present with hearing loss and disproportionately poor speech discrimination for the degree of hearing loss. Although cochlear implant is the treatment of choice, current evidence show that it benefits only those patients with endocochlear lesions, but not those with cochlear nerve deficiency or central nervous system disorders. As auditory neuropathy is a disorder with potential long-term impact on a child's development, early hearing screen using both OAE and ABR should be carried out on all newborns and infants to allow early detection and intervention.
    Matched MeSH terms: Evoked Potentials, Auditory, Brain Stem
  2. Lyn PC
    Ann Acad Med Singap, 1987 Apr;16(2):310-2.
    PMID: 3318659
    Of the seventy cases of cerebral malaria seen at the Duchess of Kent Hospital, Sandakan between January 1984 and June 1986, 57 (81.4%) were due to plasmodia falciparum and 13 (18.6%) were due to mixed p. vivax--p. falciparum infections. Mixed infection cerebral malaria was associated with a more severe anaemia and may carry a poorer prognosis. Indigenous children under five years of age are particularly at risk of death from mixed infections.
    Matched MeSH terms: Brain Diseases/mortality*; Brain Diseases/parasitology
  3. Lau KF, Tan KS, Goh KJ, Ramli N, Tai SM
    Ann Acad Med Singap, 2019 Mar;48(3):109-111.
    PMID: 30997481
    Matched MeSH terms: Brain Stem Infarctions/complications; Brain Stem Infarctions/physiopathology*
  4. Mihardja M, Roy J, Wong KY, Aquili L, Heng BC, Chan YS, et al.
    Ann N Y Acad Sci, 2020 10;1478(1):43-62.
    PMID: 32700392 DOI: 10.1111/nyas.14436
    Alzheimer's disease (AD) is an age-related neurodegenerative disorder characterized by the hallmark pathologies of amyloid-beta plaques and neurofibrillary tangles. Symptoms of this devastating disease include behavioral changes and deterioration of higher cognitive functions. Impairment of neurogenesis has also been shown to occur in AD, which adversely impacts new neuronal cell growth, differentiation, and survival. This impairment possibly results from the cumulative effects of the various pathologies of AD. Preclinical studies have suggested that the administration of melatonin-the pineal hormone primarily responsible for the regulation of the circadian rhythm-targets the effects of AD pathologies and improves cognitive impairment. It is postulated that by mitigating the effect of these pathologies, melatonin can also rescue neurogenesis impairment. This review aims to explore the effect of AD pathologies on neurogenesis, as well as the mechanisms by which melatonin is able to ameliorate AD pathologies to potentially promote neurogenesis.
    Matched MeSH terms: Brain/metabolism; Brain/pathology
  5. Poon CH, Heng BC, Lim LW
    Ann N Y Acad Sci, 2021 01;1484(1):9-31.
    PMID: 32808327 DOI: 10.1111/nyas.14458
    Advances in characterizing molecular profiles provide valuable insights and opportunities for deciphering the neuropathology of depression. Although abnormal brain-derived neurotrophic factor (BDNF) expression in depression has gained much support from preclinical and clinical research, how it mediates behavioral alterations in the depressed state remains largely obscure. Environmental factors contribute significantly to the onset of depression and produce robust epigenetic changes. Epigenetic regulation of BDNF, as one of the most characterized gene loci in epigenetics, has recently emerged as a target in research on memory and psychiatric disorders. Specifically, epigenetic alterations of BDNF exons are heavily involved in mediating memory functions and antidepressant effects. In this review, we discuss key research on stress-induced depression from both preclinical and clinical studies, which revealed that differential epigenetic regulation of specific BDNF exons is associated with depression pathophysiology. Considering that BDNF has a central role in depression, we argue that memory extinction, an adaptive response to fear exposure, is dependent on BDNF modulation and holds promise as a prospective target for alleviating or treating depression and anxiety disorders.
    Matched MeSH terms: Brain-Derived Neurotrophic Factor/genetics*
  6. Lee KW, Ching SM, Devaraj NK, Hoo FK
    Ann Transl Med, 2020 Sep;8(17):1060.
    PMID: 33145279 DOI: 10.21037/atm-20-1579
    Background: Certain candidate genes have been associated with obesity. The goal of this study is to determine the association between thirteen neuroendocrine disorder-related candidate genes and pre-pregnancy obesity among gestational diabetes mellitus (GDM) patients using the stratification approach defined the Asian and International criteria-based body mass index (BMI).

    Methods: This was a post-hoc case-control exploratory sub-analysis of a cross-sectional study among GDM women to determine which candidate single nucleotide polymorphisms (SNPs) related to neuroendocrine disorders may be associated with obesity. Factors were adjusted for socio-demographic characteristics and concurrent medical problems in this particular population. Pre-pregnancy BMI and concurrent medical profiles were obtained from maternal health records. Obesity is defined as BMI of ≥27.5 kg/m2 for Asian criteria-based BMI and >30 kg/m2 for International criteria-based BMI. Thirteen candidate genes were genotyped using Agena® MassARRAY and examined for association with pre-pregnancy obesity using multiple logistic regression analysis. The significant difference threshold was set at P value <0.05.

    Results: Three hundred and twelve GDM women were included in this study; 60.9% and 44.2% of GDM patients were obese using Asian and International criteria-based BMI, respectively. GDM patients with AA or AG genotypes in specific SNP of brain-derived neurotrophic factor (BDNF) (G > A in rs6265) are more likely to be obese (adjusted odd ratio =2.209, 95% CI, 1.305, 3.739, P=0.003) compared to those who carry the GG genotype in the SNP adjusted for parity, underlying with asthma, heart disease, anaemia, education background in the International criteria-based BMI stratification group. On the other hand, there were no associations between other candidate genes (NRG1, FKBP5, RORA, OXTR, PLEKHG1, HTR2C, LHPP, SDK2, TEX51, EPHX2, NPY5R and ANO2) and maternal obesity.

    Conclusions: In summary, BDNF rs6265 is significantly associated with pre-pregnancy obesity among GDM patients. The exact role of BDNF adjusted for diet intake and lifestyle factors merits further investigation.

    Matched MeSH terms: Brain-Derived Neurotrophic Factor
  7. Lee YK, Bister M, Salleh YM, Blanchfield P
    PMID: 19163841 DOI: 10.1109/IEMBS.2008.4650338
    Software technology enables computerized analysis to offer second opinion in various screening and diagnostic tasks to assist the clinicians. Yet, the performance of these computerized methods for medical images is questioned by experts in CAD research, owing to the use of different databases and criteria for evaluating the computer results for comparison. This paper intends to substantiate this statement by illustrating the effects of such issues with the use of 1D physiologic data and multiple databases. For this purpose, the detection of desaturation events in Sp02 and spike events in EEG are used. This is the first time that comparison between different algorithms on a common basis is carried out on an individual effort. The appraisal for all the algorithms is made on the same databases and criteria. It is surprising to find that issues for 2/3D images concur with those found in 1D data here. In evaluating the accuracy of a new algorithm, a single independent database gives results fast. This paper reveals weaknesses of such an approach. It is hoped that the supportive evidence shown here is enough for researchers to innovate a better platform for credibility in reporting performance comparison of computerized analysis algorithms.
    Matched MeSH terms: Brain/physiology*
  8. Yaacob H, Karim I, Wahab A, Kamaruddin N
    PMID: 23367309 DOI: 10.1109/EMBC.2012.6347374
    Emotions are ambiguous. Many techniques have been employed to perform emotion prediction and to understand emotional elicitations. Brain signals measured using electroencephalogram (EEG) are also used in studies about emotions. Using KDE as feature extraction technique and MLP for performing supervised learning on the brain signals. It has shown that all channels in EEG can capture emotional experience. In addition it was also indicated that emotions are dynamic as represented by the level of valence and the intensity of arousal. Such findings are useful in biomedical studies, especially in dealing with emotional disorders which can results in using a two-channel EEG device for neurofeedback applications.
    Matched MeSH terms: Brain/physiology*
  9. Ting CM, Samdin SB, Salleh ShH, Omar MH, Kamarulafizam I
    PMID: 23367426 DOI: 10.1109/EMBC.2012.6347491
    This paper applies an expectation-maximization (EM) based Kalman smoother (KS) approach for single-trial event-related potential (ERP) estimation. Existing studies assume a Markov diffusion process for the dynamics of ERP parameters which is recursively estimated by optimal filtering approaches such as Kalman filter (KF). However, these studies only consider estimation of ERP state parameters while the model parameters are pre-specified using manual tuning, which is time-consuming for practical usage besides giving suboptimal estimates. We extend the KF approach by adding EM based maximum likelihood estimation of the model parameters to obtain more accurate ERP estimates automatically. We also introduce different model variants by allowing flexibility in the covariance structure of model noises. Optimal model selection is performed based on Akaike Information Criterion (AIC). The method is applied to estimation of chirp-evoked auditory brainstem responses (ABRs) for detection of wave V critical for assessment of hearing loss. Results shows that use of more complex covariances are better estimating inter-trial variability.
    Matched MeSH terms: Brain Stem/pathology
  10. Anwar A, Mungroo MR, Khan S, Fatima I, Rafique R, Kanwal, et al.
    Antibiotics (Basel), 2020 Apr 17;9(4).
    PMID: 32316387 DOI: 10.3390/antibiotics9040188
    Balamuthia mandrillaris and Naegleriafowleri are opportunistic protozoan pathogens capable of producing infection of the central nervous system with more than 95% mortality rate. Previously, we have synthesized several compounds with antiamoebic properties; however, synthesis of compounds that are analogues of clinically used drugs is a highly desirable approach that can lead to effective drug development against these devastating infections. In this regard, compounds belonging to the azole class possess wide range of antimicrobial properties and used clinically. In this study, six novel benzimidazole, indazole, and tetrazole derivatives were synthesized and tested against brain-eating amoebae. These compounds were tested for their amoebicidal and static properties against N. fowleri and B. mandrillaris. Furthermore, the compounds were conjugated with silver nanoparticles and characterized. The synthetic heterocyclic compounds showed up to 72% and 65% amoebicidal activities against N. fowleri and B. mandrillaris respectively, while expressing up to 75% and 70% amoebistatic activities, respectively. Following conjugation with silver nanoparticles, amoebicidal activities of the drugs increased by up to 46 and 36% versus B. mandrillaris and N. fowleri. Minimal effects were observed when the compounds were evaluated against human cells using cytotoxicity assays. In summary, azole compounds exhibited potent activity against N. fowleri and B. mandrillaris. Moreover, conjugation of the azole compounds with silver nanoparticles further augmented the capabilities of the compounds against amoebae.
    Matched MeSH terms: Brain
  11. Chew WK, Segarra I, Ambu S, Mak JW
    Antimicrob Agents Chemother, 2012 Apr;56(4):1762-8.
    PMID: 22271863 DOI: 10.1128/AAC.05183-11
    Toxoplasma gondii is a parasite that generates latent cysts in the brain; reactivation of these cysts may lead to fatal toxoplasmic encephalitis, for which treatment remains unsuccessful. We assessed spiramycin pharmacokinetics coadministered with metronidazole, the eradication of brain cysts and the in vitro reactivation. Male BALB/c mice were fed 1,000 tachyzoites orally to develop chronic toxoplasmosis. Four weeks later, infected mice underwent different treatments: (i) infected untreated mice (n = 9), which received vehicle only; (ii) a spiramycin-only group (n = 9), 400 mg/kg daily for 7 days; (iii) a metronidazole-only group (n = 9), 500 mg/kg daily for 7 days; and (iv) a combination group (n = 9), which received both spiramycin (400 mg/kg) and metronidazole (500 mg/kg) daily for 7 days. An uninfected control group (n = 10) was administered vehicle only. After treatment, the brain cysts were counted, brain homogenates were cultured in confluent Vero cells, and cysts and tachyzoites were counted after 1 week. Separately, pharmacokinetic profiles (plasma and brain) were assessed after a single dose of spiramycin (400 mg/kg), metronidazole (500 mg/kg), or both. Metronidazole treatment increased the brain spiramycin area under the concentration-time curve from 0 h to ∞ (AUC(0-∞)) by 67% without affecting its plasma disposition. Metronidazole plasma and brain AUC(0-∞) values were reduced 9 and 62%, respectively, after spiramycin coadministration. Enhanced spiramycin brain exposure after coadministration reduced brain cysts 15-fold (79 ± 23 for the combination treatment versus 1,198 ± 153 for the untreated control group [P < 0.05]) and 10-fold versus the spiramycin-only group (768 ± 125). Metronidazole alone showed no effect (1,028 ± 149). Tachyzoites were absent in the brain. Spiramycin reduced in vitro reactivation. Metronidazole increased spiramycin brain penetration, causing a significant reduction of T. gondii brain cysts, with potential clinical translatability for chronic toxoplasmosis treatment.
    Matched MeSH terms: Brain/metabolism; Brain/parasitology
  12. Sha'fie MSA, Rathakrishnan S, Hazanol IN, Dali MHI, Khayat ME, Ahmad S, et al.
    Antioxidants (Basel), 2020 Dec 09;9(12).
    PMID: 33317056 DOI: 10.3390/antiox9121253
    Microglial cells are the primary immune cell resident in the brain. Growing evidence indicates that microglial cells play a prominent role in alcohol-induced brain pathologies. However, alcohol-induced effects on microglial cells and the underlying mechanisms are not fully understood, and evidence exists to support generation of oxidative stress due to NADPH oxidases (NOX_-mediated production of reactive oxygen species (ROS). Here, we investigated the role of the oxidative stress-sensitive Ca2+-permeable transient receptor potential melastatin-related 2 (TRPM2) channel in ethanol (EtOH)-induced microglial cell death using BV2 microglial cells. Like H2O2, exposure to EtOH induced concentration-dependent cell death, assessed using a propidium iodide assay. H2O2/EtOH-induced cell death was inhibited by treatment with TRPM2 channel inhibitors and also treatment with poly(ADP-ribose) polymerase (PARP) inhibitors, demonstrating the critical role of PARP and the TRPM2 channel in EtOH-induced cell death. Exposure to EtOH, as expected, led to an increase in ROS production, shown using imaging of 2',7'-dichlorofluorescein fluorescence. Consistently, EtOH-induced microglial cell death was suppressed by inhibition of NADPH oxidase (NOX) as well as inhibition of protein kinase C. Taken together, our results suggest that exposure to high doses of ethanol can induce microglial cell death via the NOX/ROS/PARP/TRPM2 signaling pathway, providing novel and potentially important insights into alcohol-induced brain pathologies.
    Matched MeSH terms: Brain
  13. Doufesh H, Faisal T, Lim KS, Ibrahim F
    Appl Psychophysiol Biofeedback, 2012 Mar;37(1):11-8.
    PMID: 21965118 DOI: 10.1007/s10484-011-9170-1
    This study investigated the proposition of relaxation offered by performing the Muslim prayers by measuring the alpha brain activity in the frontal (F3-F4), central (C3-C4), parietal (P3-P4), and occipital (O1-O2) electrode placements using the International 10-20 System. Nine Muslim subjects were asked to perform the four required cycles of movements of Dhuha prayer, and the EEG were subsequently recorded with open eyes under three conditions, namely, resting, performing four cycles of prayer while reciting the specific verses and supplications, and performing four cycles of acted salat condition (prayer movements without any recitations). Analysis of variance (ANOVA) tests revealed that there were no significant difference in the mean alpha relative power (RP(α)) between the alpha amplitude in the Dhuha prayer and the acted conditions in all eight electrode positions. However, the mean RP(α) showed higher alpha amplitude during the prostration position of the Dhuha prayer and acted condition at the parietal and occipital regions in comparison to the resting condition. Findings were similar to other studies documenting increased alpha amplitude in parietal and occipital regions during meditation and mental concentration. The incidence of increased alpha amplitude suggested parasympathetic activation, thus indicating a state of relaxation. Subsequent studies are needed to delineate the role of mental concentration, and eye focus, on alpha wave amplitude while performing worshipping acts.
    Matched MeSH terms: Brain/physiology
  14. Sulieman A, Mahmoud MZ, Serhan O, Alonazi B, Alkhorayef M, Alzimami K, et al.
    Appl Radiat Isot, 2018 Nov;141:261-265.
    PMID: 30054177 DOI: 10.1016/j.apradiso.2018.07.011
    Patient effective doses and the associated radiation risks arising from particular computed tomography (CT) imaging procedures are assessed. The objectives of this research are to measure radiation doses for patients and to quantify the radiogenic risks from CT brain and chest procedures. Patient data were collected from five calibrated CT modality machines in Saudi Arabia. The results are from a study of a total of 60 patients examined during CT procedures using the calibrated CT units. For CT brain and chest, the mean patient effective doses were 1.9 mSv (with a range of 0.6-2.5 mSv) and 7.4 mSv (with a range of 0.5-34.8 mSv) respectively. The radiogenic risk to patients ranged from between 10-5 and 10-4 per procedure. With 65% of the CT procedure cases diagnosed as normal, this prompts re-evaluation of the referral criteria. The establishment of diagnostic reference levels (DRL) and implementation of radiation dose optimisation measures would further help reduce doses to optimal values.
    Matched MeSH terms: Brain
  15. Naidu KR, Kumar KS, Arulselvan P, Reddy CB, Lasekan O
    Arch Pharm (Weinheim), 2012 Dec;345(12):957-63.
    PMID: 23015406 DOI: 10.1002/ardp.201200192
    A series of α-hydroxyphosphonates were synthesized from the reaction of aldehyde (1) with triethylphosphite (2) in the presence of oxone and evaluated for their antioxidant properties against lipid peroxidation, reduced glutathione, superoxide dismutase, and catalase. The majority of the compounds showed promising antioxidant activity. Diethyl anthracen-9-yl (hydroxy) methylphosphonate (3n) is the most potent and biologically active compound against free radicals.
    Matched MeSH terms: Brain/drug effects; Brain/enzymology; Brain/metabolism
  16. Manonmani V, Wallace SJ
    Arch Dis Child, 1994 Apr;70(4):288-90.
    PMID: 8185360
    The cases are described of eight children, five of them girls, who had epilepsy with myoclonic absences. The mean age of onset was 4.9 years. Brief episodes of loss of awareness with bilateral clonic jerking of the upper limbs were associated with rhythmic 3 cycles/second spike-wave discharges on electroencephalogram. Generalised tonic-clonic or astatic seizures, or both, also occurred in seven patients. All now have learning difficulties, and seven have behavioural problems. Conventional treatment for absences was effective in only two children. Of six patients treated with lamotrigine, five have improved substantially, but only one is in sustained complete remission. One recently diagnosed patient continues to have frequent myoclonic absences. As the response to treatment and long term outcome are much poorer, it is important to differentiate myoclonic absences from typical childhood absence epilepsy.
    Matched MeSH terms: Brain/physiopathology
  17. Lim SY, Hodaie M, Fallis M, Poon YY, Mazzella F, Moro E
    Arch. Neurol., 2010 May;67(5):584-8.
    PMID: 20457958 DOI: 10.1001/archneurol.2010.69
    Gamma knife thalamotomy (GKT) has been used as a therapeutic option for patients with disabling tremor refractory to medications. Impressive improvement of tremor has been reported in the neurosurgical literature, but the reliability of such data has been questioned.
    Matched MeSH terms: Brain Edema/etiology; Brain Edema/pathology; Brain Edema/physiopathology
  18. Lim SY, Mason WP, Young NP, Chen R, Bower JH, McKeon A, et al.
    Arch. Neurol., 2009 Oct;66(10):1285-7.
    PMID: 19822786 DOI: 10.1001/archneurol.2009.203
    OBJECTIVE:
    To describe and provide audiovisual documentation of a syndrome of polymyoclonus, laryngospasm, and cerebellar ataxia associated with adenocarcinoma and multiple neural cation channel autoantibodies.

    DESIGN:
    Case report with video.

    SETTING:
    University hospitals. Patient A 69-year-old woman presented with subacute onset of whole-body tremulousness and laryngospasm attributed to gastroesophageal reflux.

    RESULTS:
    Further evaluation revealed polymyoclonus, cerebellar ataxia, and laryngospasm suspicious of an underlying malignant neoplasm. Surface electromyography of multiple limb muscles confirmed the presence of polymyoclonus. The patient was seropositive for P/Q-type voltage-gated calcium channel antibody; subsequently, whole-body fluorine 18 fluorodeoxyglucose positron emission tomography and cervical lymph node biopsy revealed widespread metastatic adenocarcinoma. Follow-up serologic evaluation revealed calcium channel antibodies (P/Q type and N type) and potassium channel antibody.

    CONCLUSIONS:
    We highlight the importance of recognizing polymyoclonus. To our knowledge, this is also the first description of a syndrome of polymyoclonus, laryngospasm, and ataxia associated with adenocarcinoma and these cation channel antibodies.
    Matched MeSH terms: Brain Neoplasms/complications*; Brain Neoplasms/pathology; Brain Neoplasms/radionuclide imaging
  19. Halim AS, Wan Ahmad Kamal WS, Noor NM, Abdullah S
    Arch Plast Surg, 2013 Nov;40(6):687-96.
    PMID: 24286040 DOI: 10.5999/aps.2013.40.6.687
    Ischemic preconditioning has been shown to improve the outcomes of hypoxic tolerance of the heart, brain, lung, liver, jejunum, skin, and muscle tissues. However, to date, no report of ischemic preconditioning on vascularized bone grafts has been published.
    Matched MeSH terms: Brain
  20. Mumtaz W, Saad MNBM, Kamel N, Ali SSA, Malik AS
    Artif Intell Med, 2018 01;84:79-89.
    PMID: 29169647 DOI: 10.1016/j.artmed.2017.11.002
    BACKGROUND: The abnormal alcohol consumption could cause toxicity and could alter the human brain's structure and function, termed as alcohol used disorder (AUD). Unfortunately, the conventional screening methods for AUD patients are subjective and manual. Hence, to perform automatic screening of AUD patients, objective methods are needed. The electroencephalographic (EEG) data have been utilized to study the differences of brain signals between alcoholics and healthy controls that could further developed as an automatic screening tool for alcoholics.

    METHOD: In this work, resting-state EEG-derived features were utilized as input data to the proposed feature selection and classification method. The aim was to perform automatic classification of AUD patients and healthy controls. The validation of the proposed method involved real-EEG data acquired from 30 AUD patients and 30 age-matched healthy controls. The resting-state EEG-derived features such as synchronization likelihood (SL) were computed involving 19 scalp locations resulted into 513 features. Furthermore, the features were rank-ordered to select the most discriminant features involving a rank-based feature selection method according to a criterion, i.e., receiver operating characteristics (ROC). Consequently, a reduced set of most discriminant features was identified and utilized further during classification of AUD patients and healthy controls. In this study, three different classification models such as Support Vector Machine (SVM), Naïve Bayesian (NB), and Logistic Regression (LR) were used.

    RESULTS: The study resulted into SVM classification accuracy=98%, sensitivity=99.9%, specificity=95%, and f-measure=0.97; LR classification accuracy=91.7%, sensitivity=86.66%, specificity=96.6%, and f-measure=0.90; NB classification accuracy=93.6%, sensitivity=100%, specificity=87.9%, and f-measure=0.95.

    CONCLUSION: The SL features could be utilized as objective markers to screen the AUD patients and healthy controls.

    Matched MeSH terms: Brain/physiopathology*; Brain Waves*
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