Displaying publications 21 - 40 of 41 in total

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  1. Muthukumaran M, Dhinagaran G, Narayanan V, Raju T, Venkatachalam K, Karthika PC, et al.
    J Nanosci Nanotechnol, 2019 Nov 01;19(11):7215-7220.
    PMID: 31039878 DOI: 10.1166/jnn.2019.16671
    Graphene oxide/Cuprous oxide (GO/Cu₂O) composite is a visible light photocatalyst for the degradation of dyes. A simple and efficient approach for preparing GO/Cu₂O composite adopted in this study involves reducing cuprous oxide precursors in the presence of graphene oxide using an aqueous solution of pulp derived from banana fruit. The GO/Cu₂O composite was characterized by Fourier transform infrared spectroscopy (FT-IR), Diffused reflectance Ultraviolet visible spectroscopy (DRS UV-Vis), Raman spectroscopy and Field Emission Scanning electron microscopy (FE-SEM). Cu₂O particles were distributed randomly on the graphene oxide sheets due to the template effect of GO. The results showed higher photocatalytic activity for the composite (band gap 2.13 eV), for the degradation of the organic dyes (Methylene blue and Rhodamine-B). The enhanced photocatalytic activity is due to effective charge transfer from GO to Cu₂O, and high specific surface area which improves the effective separation of the generated electron-hole pairs. Our present study is inspired by a facile, low cost, green production of (GO/Cu₂O) composite whose photocatalytic activity can be extended to degradation of all other water-born textile dyes.
  2. Mehbodniya A, Moghavvemi M, Narayanan V, Muthusamy KA, Hamdi M, Waran V
    World Neurosurg, 2020 Feb;134:e379-e386.
    PMID: 31639505 DOI: 10.1016/j.wneu.2019.10.080
    OBJECTIVES: The evaluation of sources of error when preparing, printing, and using 3-dimensional (3D) printed head models for training purposes.

    METHODS: Two 3D printed models were designed and fabricated using actual patient imaging data with reference marker points embedded artificially within these models that were then registered to a surgical navigation system using 3 different methods. The first method uses a conventional manual registration, using the actual patient's imaging data. The second method is done by directly scanning the created model using intraoperative computed tomography followed by registering the model to a new imaging dataset manually. The third is similar to the second method of scanning the model but eventually uses an automatic registration technique. The errors for each experiment were then calculated based on the distance of the surgical navigation probe from the respective positions of the embedded marker points.

    RESULTS: Errors were found in the preparation and printing techniques, largely depending on the orientation of the printed segment and postprocessing, but these were relatively small. Larger errors were noted based on a couple of variables: if the models were registered using the original patient imaging data as opposed to using the imaging data from directly scanning the model (1.28 mm vs. 1.082 mm), and the accuracy was best using the automated registration techniques (0.74 mm).

    CONCLUSION: Spatial accuracy errors occur consistently in every 3D fabricated model. These errors are derived from the fabrication process, the image registration process, and the surgical process of registration.

  3. Hamzah N, Mohamad NA, Thiruselvam I, Hariri F, Veeramuthu V, Mazlan M, et al.
    Appl Neuropsychol Adult, 2019 08 21;28(4):416-426.
    PMID: 31431094 DOI: 10.1080/23279095.2019.1648264
    This study assessed the validity (construct validity) and reliability (internal consistency) of the Neuropsychological Assessment Battery Screening Module (S-NAB) in detecting mild cognitive deficit/alteration in multicultural, multilingual, and multiethnic mild traumatic brain injury (mTBI) population of Malaysia. S-NAB and Montreal Cognitive Assessment (MoCA) data from 114 patients with mTBI (93 males; 21 females) aged 18 to 60 years old were obtained at University Malaya Medical Center, Malaysia. The mean age was 28.17 ± 8.57 years and mean education years was 12.40 ± 2.01. Convergent validity was assessed between S-NAB domain scores and MoCA total scores by using Pearson's correlation and internal consistency was assessed using Cronbach's alpha. Acceptable internal consistency (α ≥ .70) was found for Attention, Language, and Memory domains but weak internal consistencies (α 
  4. Syed Alwi SM, Narayanan V, Mohd Taib NA, Che Din N
    J Clin Exp Neuropsychol, 2021 07;43(5):534-545.
    PMID: 34369307 DOI: 10.1080/13803395.2021.1945539
    Introduction: Breast cancer survivors frequently develop cognitive impairment following chemotherapy which can significantly hamper their well-being, ability to function independently, and overall quality of life. Evidence of cognitive functioning in breast cancer survivors from lower and middle-income countries remains scarce. We examined the prevalence of cognitive impairment among Malaysian multiethnic early-stage breast cancer survivors one to three years post-chemotherapy.Methods: This cross-sectional study included 160 breast cancer survivors from the University Malaya Medical Center (UMMC). The cognitive assessments used included the Montreal Cognitive Assessment (MoCA-BM), the Rey Auditory and Verbal Learning Test (RAVLT-BM), and the digit span and arithmetic of the Working Memory Index (WMI) of Wechsler Adult Intelligence Scale-IV (WAIS-IV). Data were analyzed using independent sample t-tests and Pearson's correlation.Results: Our breast cancer survivors demonstrated poor performances in MoCA-BM (31.9%) RAVLT-BM, recall (53.8%), and WMI of WAIS-IV (51.3%) with 30.6% of them performed poorly in all three cognitive tests administered. There were no significant mean group differences in cognitive performances between <24 months after chemotherapy and ≥24 months after chemotherapy.Conclusions: A high proportion of breast cancer survivors exhibited poor performances in the cognitive assessments. Cognitive rehabilitation programmes tailored to the needs of these survivors should be incorporated into cancer care management.
  5. Syed Alwi SM, Narayanan V, Mohd Taib NA, Che Din N
    Support Care Cancer, 2022 Mar;30(3):2793-2801.
    PMID: 34841453 DOI: 10.1007/s00520-021-06686-9
    PURPOSE: Health-related quality of life (QoL) is an important outcome measure in breast cancer management. Evidence of QoL of breast cancer patients in lower and middle-income countries remains scarce. We examined the level of QoL, cognitive impairment, psychological distresses, and the predictors of QoL among multiethnic Malaysian early-stage breast cancer survivors 1 to 3 years following chemotherapy.

    METHODS: A total of 160 breast cancer survivors from the University of Malaya Medical Centre (UMMC) participated in this cross-sectional study. Their QoL was evaluated with the Malay version of the European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire Core 30 (QLQ-C30) version 3.0. Cognitive functioning and psychological distress were evaluated using the Malay version of the Montreal Cognitive Assessment (MoCA-BM) and Hospital Anxiety and Depression Scale (HADS), respectively. Data analysis was performed with Pearson's correlation and multiple regression analyses.

    RESULTS: At 1- to 3-year post-chemotherapy, the mean EORTC QLQ-C30 global health status of the breast cancer survivors was relatively low (60.5 over 100, SD = 10.88). One-third (31.9%) of them demonstrated cognitive impairment, and another 3.2% showed moderate to severe anxiety levels. The significant predictors for global health status and functioning included age, psychological distresses, cognitive performance, fatigue, appetite loss, insomnia, pain, and constipation.

    CONCLUSION: Our breast cancer survivors demonstrated poor global health status. Health care providers and policymakers must strive to provide holistic intervention strategies to improve the multiple dimensions of QoL and the cognitive and psychological functioning of this vulnerable population.

  6. Veeramuthu V, Seow P, Narayanan V, Wong JHD, Tan LK, Hernowo AT, et al.
    Acad Radiol, 2018 09;25(9):1167-1177.
    PMID: 29449141 DOI: 10.1016/j.acra.2018.01.005
    RATIONALE AND OBJECTIVES: Magnetic resonance spectroscopy is a noninvasive imaging technique that allows for reliable assessment of microscopic changes in brain cytoarchitecture, neuronal injuries, and neurochemical changes resultant from traumatic insults. We aimed to evaluate the acute alteration of neurometabolites in complicated and uncomplicated mild traumatic brain injury (mTBI) patients in comparison to control subjects using proton magnetic resonance spectroscopy (1H magnetic resonance spectroscopy).

    MATERIAL AND METHODS: Forty-eight subjects (23 complicated mTBI [cmTBI] patients, 12 uncomplicated mTBI [umTBI] patients, and 13 controls) underwent magnetic resonance imaging scan with additional single voxel spectroscopy sequence. Magnetic resonance imaging scans for patients were done at an average of 10 hours (standard deviation 4.26) post injury. The single voxel spectroscopy adjacent to side of injury and noninjury regions were analysed to obtain absolute concentrations and ratio relative to creatine of the neurometabolites. One-way analysis of variance was performed to compare neurometabolite concentrations of the three groups, and a correlation study was done between the neurometabolite concentration and Glasgow Coma Scale.

    RESULTS: Significant difference was found in ratio of N-acetylaspartate to creatine (NAA/Cr + PCr) (χ2(2) = 0.22, P 

  7. Veeramuthu V, Narayanan V, Ramli N, Hernowo A, Waran V, Bondi MW, et al.
    World Neurosurg, 2017 Jan;97:416-423.
    PMID: 27751922 DOI: 10.1016/j.wneu.2016.10.041
    OBJECTIVE: To compare the extent of persistent neuropsychological impairment in patients with complicated mild traumatic brain injury (mTBI) and those with uncomplicated mTBI.

    METHODS: Sixty-one patients with mTBI (Glasgow Coma Scale score 13-15) were recruited prospectively, categorized according to baseline computed tomography findings, and subjected to neuropsychological assessment at initial admission (n = 61) as well as at a 6-month follow-up (n = 30). The paired t test, Cohen's d effect size calculation, and repeated-measures analysis of variance were used to establish the differences between the 2 groups in terms of neuropsychological performance.

    RESULTS: A trend toward poorer neuropsychological performance among the patients with complicated mTBI was observed during admission; however, performance in this group improved over time. In contrast, the uncomplicated mTBI group showed slower recovery, especially in tasks of memory, visuospatial processing, and executive functions, at follow-up.

    CONCLUSIONS: Our findings suggest that despite the broad umbrella designation of mTBI, the current classification schemes of injury severity for mild neurotrauma should be revisited. They also raise questions about the clinical relevance of both traumatic focal lesions and the absence of visible traumatic lesions on brain imaging studies in patients with milder forms of head trauma.

  8. Syed Alwi SM, Mazlan M, Mohd Taib NA, Che Din N, Narayanan V
    PLoS One, 2022;17(11):e0277056.
    PMID: 36395277 DOI: 10.1371/journal.pone.0277056
    OBJECTIVE: Chemotherapy-related cognitive impairment (CRCI) is a well-known phenomenon among breast cancer survivors. Cognitive impairment among breast cancer survivors can significantly affect their quality of life and ability to function independently. However, there is a lack of specific and focused cognitive intervention to improve their cognitive performances. This study aimed to develop a tailored cognitive intervention framework module by adapting the attention and memory interventions from the Cognitive Rehabilitation Manual of the Brain Injury Interdisciplinary Special Interest Group (BI-SIG) of the American Congress of Rehabilitation Medicine (ACRM) and incorporating them with the relevant exercises for cognitive rehabilitation for Malaysian breast cancer survivors with CRCI based on the consensus agreement of the expert panel.

    METHODS AND ANALYSIS: The Delphi consensus technique was conducted online to review and evaluate the framework module. A panel of experts, including rehabilitation medicine physicians, occupational therapists, and clinical psychologists in Malaysia, was invited to participate in this study. For each round, the expert consensus was defined as more than 90% of the expert panel agreeing or strongly agreeing with the proposed items.

    RESULTS: A total of 33 practitioners completed the three Delphi rounds. 72.7% of the expert panel have been practising in their relevant clinical fields for more than six years (M = 10.67, SD = 5.68). In Round 1, 23% of the experts suggested that the framework module for attention training required further improvements, specifically in the language (M = 1.97, SD = 0.75) and instructions (M = 2.03, SD = 0.71) provided. In Round 2, 15% of the experts recommended additional changes in the instruction (M = 2.15, SD = 0.67) for attention training. Amendments made to the framework module in line with the recommendations provided by the experts resulted in a higher level of consensus, as 94% to 100% of the experts in Round 3 concluded the framework module was suitable and comprehensive for our breast cancer survivors. Following the key results, the objectives were practical, and the proposed approaches, strategies, and techniques for attention and memory training were feasible. The clarity of the instructions, procedures, verbatim transcripts, and timeframe further enhanced the efficacy and utility of the framework module.

    CONCLUSIONS: This study found out that the cognitive intervention framework module for breast cancer survivors with cognitive impairment following chemotherapy can be successfully developed and feasible to be implemented using Delphi technique.

  9. Wan Jabarudin WNE, Narayanan V, Hamdan M, Gunasagran Y, Thavarajan RD, Kamarudin M, et al.
    Int J Gynaecol Obstet, 2024 Feb 15.
    PMID: 38358264 DOI: 10.1002/ijgo.15429
    OBJECTIVE: To evaluate oral rehydration therapy (ORT) compared with intravenous rehydration therapy (IVT) in the early inpatient management of hyperemesis gravidarum (HG).

    METHODS: A total of 124 women hospitalized for HG from February 10, 2021 till January 6, 2023 were randomized to ORT (n = 61) or IVT (n = 63) for an initial 12 h. Inclusion criteria includes women older than 18 years, with a viable intrauterine pregnancy less than 14 weeks at their first hospitalization for HG with ketonuria of at least 2+. Primary outcomes were (1) satisfaction score with allocated intervention, (2) weight change, and (3) ketonuria change at 12 h. Secondary outcomes included vomiting frequency, nausea score, serial vital signs, hematocrit and electrolyte levels at 12 h, deviation from treatment protocol (cross-over therapy), participant recommendation of allocated treatment to a friend, and length of hospital stay.

    RESULTS: Primary outcomes of (1) participant satisfaction score (on a 0-10 visual numerical rating scale) was 7 (interquartile range [IQR] 5-8) versus 9 (IQR 8-10), P 

  10. Waran V, Narayanan V, Karuppiah R, Pancharatnam D, Chandran H, Raman R, et al.
    J Surg Educ, 2014 Mar-Apr;71(2):193-7.
    PMID: 24602709 DOI: 10.1016/j.jsurg.2013.08.010
    The traditionally accepted form of training is direct supervision by an expert; however, modern trends in medicine have made this progressively more difficult to achieve. A 3-dimensional printer makes it possible to convert patients imaging data into accurate models, thus allowing the possibility to reproduce models with pathology. This enables a large number of trainees to be trained simultaneously using realistic models simulating actual neurosurgical procedures. The aim of this study was to assess the usefulness of these models in training surgeons to perform standard procedures that require complex techniques and equipment.
  11. Lim KS, Fong SL, Thuy Le MA, Ahmad Bazir S, Narayanan V, Ismail N, et al.
    Epilepsy Res, 2020 05;162:106298.
    PMID: 32172144 DOI: 10.1016/j.eplepsyres.2020.106298
    INTRODUCTION: Video-EEG monitoring is one of the key investigations in epilepsy pre-surgical evaluation but limited by cost. This study aimed to determine the efficacy and safety of a 48-hour (3-day) video EEG monitoring, with rapid pre-monitoring antiepileptic drugs withdrawal.

    MATERIAL AND METHODS: This is a retrospective study of epilepsy cases with VEM performed in University Malaya Medical Center (UMMC), Kuala Lumpur, from January 2012 till August 2016.

    RESULTS: A total of 137 cases were included. The mean age was 34.5 years old (range 15-62) and 76 (55.8 %) were male. On the first 24 -h of recording (D1), 81 cases (59.1 %) had seizure occurrence, and 109 (79.6 %) by day 2 (D2). One-hundred and nine VEMs (79.6 %) were diagnostic, in guiding surgical decision or further investigations. Of these, 21 had less than 2 seizures recorded in the first 48 h but were considered as diagnostic because of concordant interictal ± ictal activities, or a diagnosis such as psychogenic non-epileptic seizure was made. Twenty-eight patients had extension of VEM for another 24-48 h, and 11 developed seizures during the extension period. Extra-temporal lobe epilepsy and seizure frequency were significant predictors for diagnostic 48 -h VEM. Three patients developed complications, including status epilepticus required anaesthetic agents (1), seizure clusters (2) with postictal psychosis or dysphasia, and all recovered subsequently.

    CONCLUSIONS: 48-h video EEG monitoring is cost-effective in resource limited setting.

  12. Narayanan V, Veeramuthu V, Ahmad-Annuar A, Ramli N, Waran V, Chinna K, et al.
    PLoS One, 2016;11(7):e0158838.
    PMID: 27438599 DOI: 10.1371/journal.pone.0158838
    The predictability of neurocognitive outcomes in patients with traumatic brain injury is not straightforward. The extent and nature of recovery in patients with mild traumatic brain injury (mTBI) are usually heterogeneous and not substantially explained by the commonly known demographic and injury-related prognostic factors despite having sustained similar injuries or injury severity. Hence, this study evaluated the effects and association of the Brain Derived Neurotrophic Factor (BDNF) missense mutations in relation to neurocognitive performance among patients with mTBI. 48 patients with mTBI were prospectively recruited and MRI scans of the brain were performed within an average 10.1 (SD 4.2) hours post trauma with assessment of their neuropsychological performance post full Glasgow Coma Scale (GCS) recovery. Neurocognitive assessments were repeated again at 6 months follow-up. The paired t-test, Cohen's d effect size and repeated measure ANOVA were performed to delineate statistically significant differences between the groups [wildtype G allele (Val homozygotes) vs. minor A allele (Met carriers)] and their neuropsychological performance across the time point (T1 = baseline/ admission vs. T2 = 6th month follow-up). Minor A allele carriers in this study generally performed more poorly on neuropsychological testing in comparison wildtype G allele group at both time points. Significant mean differences were observed among the wildtype group in the domains of memory (M = -11.44, SD = 10.0, p = .01, d = 1.22), executive function (M = -11.56, SD = 11.7, p = .02, d = 1.05) and overall performance (M = -6.89 SD = 5.3, p = .00, d = 1.39), while the minor A allele carriers showed significant mean differences in the domains of attention (M = -11.0, SD = 13.1, p = .00, d = .86) and overall cognitive performance (M = -5.25, SD = 8.1, p = .01, d = .66).The minor A allele carriers in comparison to the wildtype G allele group, showed considerably lower scores at admission and remained impaired in most domains across the timepoints, although delayed signs of recovery were noted to be significant in the domains attention and overall cognition. In conclusion, the current study has demonstrated the role of the BDNF rs6265 Val66Met polymorphism in influencing specific neurocognitive outcomes in patients with mTBI. Findings were more detrimentally profound among Met allele carriers.
  13. Seow P, Narayanan V, Romelean RJ, Wong JHD, Win MT, Chandran H, et al.
    Acad Radiol, 2020 02;27(2):180-187.
    PMID: 31155487 DOI: 10.1016/j.acra.2019.04.015
    RATIONALE AND PURPOSE: Our study evaluated the capability of magnetic resonance imaging in- and opposed-phase (IOP) derived lipid fraction as a novel prognostic biomarker of survival outcome in glioma.

    MATERIALS AND METHODS: We analyzed 46 histologically proven glioma (WHO grades II-IV) patients using standard 3T magnetic resonance imaging brain tumor protocol and IOP sequence. Lipid fraction was derived from the IOP sequence signal-loss ratio. The lipid fraction of solid nonenhancing region of glioma was analyzed, using a three-group analysis approach based on volume under surface of receiver-operating characteristics to stratify the prognostic factors into three groups of low, medium, and high lipid fraction. The survival outcome was evaluated, using Kaplan-Meier survival analysis and Cox regression model.

    RESULTS: Significant differences were seen between the three groups (low, medium, and high lipid fraction groups) stratified by the optimal cut-off point for overall survival (OS) (p ≤ 0.01) and time to progression (p ≤ 0.01) for solid nonenhancing region. The group with high lipid fraction had five times higher risk of poor survival and earlier time to progression compared to the low lipid fraction group. The OS plot stratified by lipid fraction also had a strong correlation with OS plot stratified by WHO grade (R = 0.61, p < 0.01), implying association to underlying histopathological changes.

    CONCLUSION: The lipid fraction of solid nonenhancing region showed potential for prognostication of glioma. This method will be a useful adjunct in imaging protocol for treatment stratification and as a prognostic tool in glioma patients.

  14. Audrey C, Lim KS, Ahmad Zaki R, Fong SL, Chan CY, Sathis Kumar T, et al.
    Epilepsy Res, 2022 Nov;187:107033.
    PMID: 36274423 DOI: 10.1016/j.eplepsyres.2022.107033
    OBJECTIVES: Prevalence of seizures in brain tumors vary substantially between studies even with similar histopathological types. We aimed to identify the seizure prevalence of the commonest types of brain tumors.

    METHODS: Systematic computerized search of PubMed, Embase, and Web of Science were performed. The meta-analysis of pooled prevalence and 95 % confidence interval (CI) for tumor-related seizures were calculated by using a random effect model. Based on the 2014 epilepsy definition, a mean seizure prevalence of 60 % is used to indicate high seizure prevalence in this study.

    RESULTS: 74 studies that reported seizure prevalence with 23,116 patients were included in this meta-analysis. These tumors has higher seizure incidence rate (at least 60 %) with pooled prevalence of 63 % for adult with low-grade astrocytoma (95 % CI: 57-68 %), 65 % for oligodendroglioma (95% CI: 57-72 %), 72 % for oligoastrocytoma (95 % CI: 67-77 %), 81 % for ganglioglioma (95 % CI: 66-97 %) and 94 % for DNET (94 % CI: 83-100 %).

    CONCLUSION: This study highlights the type of brain tumors that carry a high seizure prevalence. Screening for subtle seizures and early management of seizures may be beneficial in patients with low-grade astrocytoma (adult), oligodendroglioma, oligoastrocytoma, ganglioglioma or DNET brain tumor.

  15. Veeramuthu V, Narayanan V, Kuo TL, Delano-Wood L, Chinna K, Bondi MW, et al.
    J Neurotrauma, 2015 Oct 1;32(19):1497-509.
    PMID: 25952562 DOI: 10.1089/neu.2014.3750
    We explored the prognostic value of diffusion tensor imaging (DTI) parameters of selected white matter (WM) tracts in predicting neuropsychological outcome, both at baseline and 6 months later, among well-characterized patients diagnosed with mild traumatic brain injury (mTBI). Sixty-one patients with mTBI (mean age=27.08; standard deviation [SD], 8.55) underwent scanning at an average of 10 h (SD, 4.26) post-trauma along with assessment of their neuropsychological performance at an average of 4.35 h (SD, 7.08) upon full Glasgow Coma Scale recovery. Results were then compared to 19 healthy control participants (mean age=29.05; SD, 5.84), both in the acute stage and 6 months post-trauma. DTI and neuropsychological measures between acute and chronic phases were compared, and significant differences emerged. Specifically, chronic-phase fractional anisotropy and radial diffusivity values showed significant group differences in the corona radiata, anterior limb of internal capsule, cingulum, superior longitudinal fasciculus, optic radiation, and genu of corpus callosum. Findings also demonstrated associations between DTI indices and neuropsychological outcome across two time points. Our results provide new evidence for the use of DTI as an imaging biomarker and indicator of WM damage occurring in the context of mTBI, and they underscore the dynamic nature of brain injury and possible biological basis of chronic neurocognitive alterations.
  16. Maniam L, Vellasamy KM, Ong TA, Teh CSJ, Jabar KA, Mariappan V, et al.
    PeerJ, 2023;11:e15305.
    PMID: 37361034 DOI: 10.7717/peerj.15305
    BACKGROUND: Uropathogenic Escherichia coli (UPEC) is the predominant agent causing various categories of complicated urinary tract infections (cUTI). Although existing data reveals that UPEC harboured numerous virulence determinants to aid its survival in the urinary tract, the reason behind the occurrence of differences in the clinical severity of uninary tract infections (UTI) demonstrated by the UPEC infection is poorly understood. Therefore, the present study aims to determine the distribution of virulence determinants and antimicrobial resistance among different phylogroups of UPEC isolated from various clinical categories of cUTI and asymptomatic bacteriuria (ASB) E. coli isolates. The study will also attempt a relational analysis of the genotypic characteristics of cUTI UPEC and ASB E. coli isolates.

    METHODS: A total of 141 UPEC isolates from cUTI and 160 ASB E. coli isolates were obtained from Universiti Malaya Medical Centre (UMMC). Phylogrouping and the occurrence of virulence genes were investigated using polymerase chain reaction (PCR). Antimicrobial susceptibility of the isolates to different classes of antibiotics was determined using the Kirby Bauer Disc Diffusion method.

    RESULTS: The cUTI isolates were distributed differentially among both Extraintestinal Pathogenic E. coli (ExPEC) and non-ExPEC phylogroups. Phylogroup B2 isolates were observed to possess the highest average aggregative virulence score (7.17), a probable representation of the capability to cause severe disease. Approximately 50% of the cUTI isolates tested in this study were multidrug resistant against common antibiotics used to treat UTI. Analysis of the occurrence of virulence genes among different cUTI categories demonstrated that UPEC isolates of pyelonephritis and urosepsis were highly virulent and had the highest average aggregative virulence scores of 7.80 and 6.89 respectively, compared to other clinical categories. Relational analysis of the occurrence of phylogroups and virulence determinants of UPEC and ASB E. coli isolates showed that 46.1% of UPEC and 34.3% of ASB E. coli from both categories were distributed in phylogroup B2 and had the highest average aggregative virulence score of 7.17 and 5.37, respectively. The data suggest that UPEC isolates which carry virulence genes from all four virulence genes groups studied (adhesions, iron uptake systems, toxins and capsule synthesis) and isolates from phylogroup B2 specifically could predispose to severe UTI involving the upper urinary tract. Therefore, specific analysis of the genotypic characteristics of UPEC could be further explored by incorporating the combination of virulence genes as a prognostic marker for predicting disease severity, in an attempt to propose a more evidence driven treatment decision-making for all UTI patients. This will go a long way in enhancing favourable therapeutic outcomes and reducing the antimicrobial resistance burden among UTI patients.

  17. Hamzah N, Narayanan V, Ramli N, Mustapha NA, Mohammad Tahir NA, Tan LK, et al.
    BMJ Open, 2019 09 18;9(9):e028711.
    PMID: 31537559 DOI: 10.1136/bmjopen-2018-028711
    OBJECTIVES: To measure the clinical, structural and functional changes of an individualised structured cognitive rehabilitation in mild traumatic brain injury (mTBI) population.

    SETTING: A single centre study, Malaysia.

    PARTICIPANTS: Adults aged between 18 and 60 years with mTBI as a result of road traffic accident, with no previous history of head trauma, minimum of 9 years education and abnormal cognition at 3 months will be included. The exclusion criteria include pre-existing chronic illness or neurological/psychiatric condition, long-term medication that affects cognitive/psychological status, clinical evidence of substance intoxication at the time of injury and major polytrauma. Based on multiple estimated calculations, the minimum intended sample size is 50 participants (Cohen's d effect size=0.35; alpha level of 0.05; 85% power to detect statistical significance; 40% attrition rate).

    INTERVENTIONS: Intervention group will receive individualised structured cognitive rehabilitation. Control group will receive the best patient-centred care for attention disorders. Therapy frequency for both groups will be 1 hour per week for 12 weeks.

    OUTCOME MEASURES: Primary: Neuropsychological Assessment Battery-Screening Module (S-NAB) scores. Secondary: Diffusion Tensor Imaging (DTI) parameters and Goal Attainment Scaling score (GAS).

    RESULTS: Results will include descriptive statistics of population demographics, CogniPlus cognitive program and metacognitive strategies. The effect of intervention will be the effect size of S-NAB scores and mean GAS T scores. DTI parameters will be compared between groups via repeated measure analysis. Correlation analysis of outcome measures will be calculated using Pearson's correlation coefficient.

    CONCLUSION: This is a complex clinical intervention with multiple outcome measures to provide a comprehensive evidence-based treatment model.

    ETHICS AND DISSEMINATION: The study protocol was approved by the Medical Research Ethics Committee UMMC (MREC ID NO: 2016928-4293). The findings of the trial will be disseminated through peer-reviewed journals and scientific conferences.

    TRIAL REGISTRATION NUMBER: NCT03237676.

  18. Lock C, Kwok J, Kumar S, Ahmad-Annuar A, Narayanan V, Ng ASL, et al.
    PMID: 30687707 DOI: 10.3389/fmed.2018.00357
    Normal pressure hydrocephalus (NPH) is a syndrome comprising gait disturbance, cognitive decline and urinary incontinence that is an unique model of reversible brain injury, but it presents as a challenging spectrum of disease cohorts. Diffusion Tensor Imaging (DTI), with its ability to interrogate structural white matter patterns at a microarchitectural level, is a potentially useful tool for the confirmation and characterization of disease cohorts at the clinical-research interface. However, obstacles to its widespread use involve the need for consistent DTI analysis and interpretation tools across collaborator sites. We present the use of DTI profiles, a simplistic methodology to interpret white matter injury patterns based on the morphology of diffusivity parameters. We examined 13 patients with complex NPH, i.e., patients with NPH and overlay from multiple comorbidities, including vascular risk burden and neurodegenerative disease, undergoing extended CSF drainage, clinical assessments, and multi-modal MR imaging. Following appropriate exclusions, we compared the morphology of DTI profiles in such complex NPH patients (n = 12, comprising 4 responders and 8 non-responders) to exemplar DTI profiles from a cohort of classic NPH patients (n = 16) demonstrating responsiveness of white matter injury to ventriculo-peritoneal shunting. In the cohort of complex NPH patients, mean age was 71.3 ± 7.6 years (10 males, 2 females) with a mean MMSE score of 21.1. There were 5 age-matched healthy controls, mean age was 73.4 ± 7.2 years (1 male, 4 females) and mean MMSE score was 26.8. In the exemplar cohort of classic NPH patients, mean age was 74.7 ± 5.9 years (10 males, 6 females) and mean MMSE score was 24.1. There were 9 age-matched healthy controls, mean age was 69.4 ± 9.7 years (4 males, 5 females) and mean MMSE score was 28.6. We found that, despite the challenges of acquiring DTI metrics from differing scanners across collaborator sites and NPH patients presenting as differing cohorts along the spectrum of disease, DTI profiles for responsiveness to interventions were comparable. Distinct DTI characteristics were demonstrated for complex NPH responders vs. non-responders. The morphology of DTI profiles for complex NPH responders mimicked DTI patterns found in predominantly shunt-responsive patients undergoing intervention for classic NPH. However, DTI profiles for complex NPH non-responders was suggestive of atrophy. Our findings suggest that it is possible to use DTI profiles to provide a methodology for rapid description of differing cohorts of disease at the clinical-research interface. By describing DTI measures morphologically, it was possible to consistently compare white matter injury patterns across international collaborator datasets.
  19. Seow P, Hernowo AT, Narayanan V, Wong JHD, Bahuri NFA, Cham CY, et al.
    Acad Radiol, 2021 12;28(12):1721-1732.
    PMID: 33023809 DOI: 10.1016/j.acra.2020.09.007
    RATIONALE AND OBJECTIVES: Gliomatous tumors are known to affect neural fiber integrity, either by displacement or destruction. The aim of this study is to investigate the integrity and distribution of the white matter tracts within and around the glioma regions using probabilistic fiber tracking.

    MATERIAL AND METHODS: Forty-two glioma patients were subjected to MRI using a standard tumor protocol with diffusion tensor imaging (DTI). The tumor and peritumor regions were delineated using snake model with reference to structural and diffusion MRI. A preprocessing pipeline of the structural MRI image, DTI data, and tumor regions was implemented. Tractography was performed to delineate the white matter (WM) tracts in the selected tumor regions via probabilistic fiber tracking. DTI indices were investigated through comparative mapping of WM tracts and tumor regions in low-grade gliomas (LGG) and high-grade gliomas (HGG).

    RESULTS: Significant differences were seen in the planar tensor (Cp) in peritumor regions; mean diffusivity, axial diffusivity and pure isotropic diffusion in solid-enhancing tumor regions; and fractional anisotropy, axial diffusivity, pure anisotropic diffusion (q), total magnitude of diffusion tensor (L), relative anisotropy, Cp and spherical tensor (Cs) in solid nonenhancing tumor regions for affected WM tracts. In most cases of HGG, the WM tracts were not completely destroyed, but found intact inside the tumor.

    DISCUSSION: Probabilistic fiber tracking revealed the existence and distribution of WM tracts inside tumor core for both LGG and HGG groups. There were more DTI indices in the solid nonenhancing tumor region, which showed significant differences between LGG and HGG.

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