Displaying publications 41 - 60 of 79 in total

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  1. Ude CC, Ng MH, Chen CH, Htwe O, Amaramalar NS, Hassan S, et al.
    Osteoarthritis Cartilage, 2015 Aug;23(8):1294-306.
    PMID: 25887366 DOI: 10.1016/j.joca.2015.04.003
    OBJECTIVES: Our previous studies on osteoarthritis (OA) revealed positive outcome after chondrogenically induced cells treatment. Presently, the functional improvements of these treated OA knee joints were quantified followed by evaluation of the mechanical properties of the engineered cartilages.
    METHODS: Baseline electromyogram (EMGs) were conducted at week 0 (pre-OA), on the locomotory muscles of nine un-castrated male sheep (Siamese long tail cross) divided into controls, adipose-derived stem cells (ADSCs) and bone marrow stem cells (BMSCs), before OA inductions. Subsequent recordings were performed at week 7 and week 31 which were post-OA and post-treatments. Afterwards, the compression tests of the regenerated cartilage were performed.
    RESULTS: Post-treatment EMG analysis revealed that the control sheep retained significant reductions in amplitudes at the right medial gluteus, vastus lateralis and bicep femoris, whereas BMSCs and ADSCs samples had no further significant reductions (P < 0.05). Grossly and histologically, the treated knee joints demonstrated the presence of regenerated neo cartilages evidenced by the fluorescence of PKH26 tracker. Based on the International Cartilage Repair Society scores (ICRS), they had significantly lower grades than the controls (P < 0.05). The compression moduli of the native cartilages and the engineered cartilages differed significantly at the tibia plateau, patella femoral groove and the patella; whereas at the medial femoral condyle, they had similar moduli of 0.69 MPa and 0.40-0.64 MPa respectively. Their compression strengths at all four regions were within ±10 MPa.
    CONCLUSION: The tissue engineered cartilages provided evidence of functional recoveries associated to the structural regenerations, and their mechanical properties were comparable with the native cartilage.
    KEYWORDS: Cartilage; Cell therapy; Function; Osteoarthritis; Regeneration
  2. Voon NS, Lau FN, Zakaria R, Md Rani SA, Ismail F, Manan HA, et al.
    Cancer Radiother, 2021 Feb;25(1):62-71.
    PMID: 33414057 DOI: 10.1016/j.canrad.2020.07.008
    PURPOSE: Nasopharyngeal carcinoma (NPC) radiotherapy (RT) irradiates parts of the brain which may cause cerebral tissue changes. This study aimed to systematically review the brain microstructure changes using MRI-based measures, diffusion tensor imaging (DTI), diffusion kurtosis imaging (DKI) and voxel-based morphometry (VBM) and the impact of dose and latency following RT.

    METHODS: PubMed and Scopus databases were searched based on PRISMA guideline to determine studies focusing on changes following NPC RT.

    RESULTS: Eleven studies fulfilled the inclusion criteria. Microstructural changes occur most consistently in the temporal region. The changes were correlated with latency in seven studies; fractional anisotropy (FA) and gray matter (GM) volume remained low even after a longer period following RT and areas beyond irradiation site with reduced FA and GM measures. For dosage, only one study showed correlation, thus requiring further investigations.

    CONCLUSION: DTI, DKI and VBM may be used as a surveillance tool in detecting brain microstructural changes of NPC patients which correlates to latency and brain areas following RT.

  3. Voon NS, Abdul Manan H, Yahya N
    Cancers (Basel), 2021 Dec 08;13(24).
    PMID: 34944811 DOI: 10.3390/cancers13246191
    Radiotherapy for head and neck cancers exposes small parts of the brain to radiation, resulting in radiation-induced changes in cerebral tissue. In this review, we determine the correlation between cognitive deterioration in patients with head and neck cancer after radiotherapy and magnetic resonance imaging (MRI) changes. Systematic searches were performed in PubMed, Scopus, and Cochrane databases in February 2021. Studies of head and neck cancer patients treated with radiotherapy and periodical cognitive and MRI assessments were included. Meta-analysis was performed to analyse the correlation of Montreal Cognitive Assessment (MoCA) scores to MRI structural and functional changes. Seven studies with a total of 404 subjects (irradiated head and neck patients, n = 344; healthy control, n = 60) were included. Most studies showed the significance of MRI in detecting microstructural and functional changes in association with neurocognitive function. The changes were seen in various brain areas, predominantly the temporal region, which also shows dose dependency (6/7 studies). An effect size (r = 0.43, p < 0.001) was reported on the correlation of MoCA scores to MRI structural and functional changes with significant correlations shown among patients treated with head and neck radiotherapy. However, the effect size appears modest.
  4. Voon NS, Manan HA, Yahya N
    J Neurooncol, 2023 Apr 04.
    PMID: 37014593 DOI: 10.1007/s11060-023-04303-9
    BACKGROUND: Glioma irradiation often unavoidably damages the brain volume and affects cognition. This study aims to evaluate the relationship of remote cognitive assessments in determining cognitive impairment of irradiated glioma patients in relation to the quality of life and MRI changes.

    METHODS: Thirty patients (16-76 aged) with two imaging (pre- and post-RT) and completed cognitive assessments were recruited. Cerebellum, right and left temporal lobes, corpus callosum, amygdala and spinal cord were delineated and their dosimetry parameters were collected. Cognitive assessments were given post-RT via telephone (Telephone Interview Cognitive Status (TICS), Telephone Montreal Cognitive Assessment (T-MoCA), Telephone Mini Addenbrooke's Cognitive Examination (Tele-MACE)). Regression models and deep neural network (DNN) were used to evaluate the relationship between brain volume, cognition and treatment dose in patients.

    RESULTS: Cognitive assessments were highly inter-correlated (r > 0.9) and impairment was shown between pre- and post-RT findings. Brain volume atrophy was shown post-RT, and cognitive impairments were correlated with radiotherapy-associated volume atrophy and dose-dependent in the left temporal lobe, corpus callosum, cerebellum and amygdala. DNN showed a good area under the curve for cognitive prediction; TICS (0.952), T-MoCA (0.909) and Tele-MACE (0.822).

    CONCLUSIONS: Cognition can be evaluated remotely in which radiotherapy-related brain injury is dose-dependent and volume-dependent. Prediction models can assist in the early identification of patients at risk for neurocognitive decline following RT for glioma, thus facilitating potential treatment interventions.

  5. Voon NS, Manan HA, Yahya N
    J Cancer Surviv, 2023 Apr 03.
    PMID: 37010777 DOI: 10.1007/s11764-023-01371-8
    PURPOSE: Irradiation of the brain regions from nasopharyngeal carcinoma (NPC) radiotherapy (RT) is frequently unavoidable, which may result in radiation-induced cognitive deficit. Using deep learning (DL), the study aims to develop prediction models in predicting compromised cognition in patients following NPC RT using remote assessments and determine their relation to the quality of life (QoL) and MRI changes.

    METHODS: Seventy patients (20-76 aged) with MRI imaging (pre- and post-RT (6 months-1 year)) and complete cognitive assessments were recruited. Hippocampus, temporal lobes (TLs), and cerebellum were delineated and dosimetry parameters were extracted. Assessments were given post-RT via telephone (Telephone Interview Cognitive Status (TICS), Telephone Montreal Cognitive Assessment (T-MoCA), Telephone Mini Addenbrooke's Cognitive Examination (Tele-MACE), and QLQ-H&N 43). Regression and deep neural network (DNN) models were used to predict post-RT cognition using anatomical and treatment dose features.

    RESULTS: Remote cognitive assessments were inter-correlated (r > 0.9). TLs showed significance in pre- and post-RT volume differences and cognitive deficits, that are correlated with RT-associated volume atrophy and dose distribution. Good classification accuracy based on DNN area under receiver operating curve (AUROC) for cognitive prediction (T-MoCA AUROC = 0.878, TICS AUROC = 0.89, Tele-MACE AUROC = 0.919).

    CONCLUSION: DL-based prediction models assessed using remote assessments can assist in predicting cognitive deficit following NPC RT. Comparable results of remote assessments in assessing cognition suggest its possibility in replacing standard assessments.

    IMPLICATIONS FOR CANCER SURVIVORS: Application of prediction models in individual patient enables tailored interventions to be provided in managing cognitive changes following NPC RT.

  6. Voon NS, Manan HA, Yahya N
    Strahlenther Onkol, 2023 Aug;199(8):706-717.
    PMID: 37280382 DOI: 10.1007/s00066-023-02089-3
    PURPOSE: Increasing evidence implicates changes in brain function following radiotherapy for head and neck cancer as precursors for brain dysfunction. These changes may thus be used as biomarkers for early detection. This review aimed to determine the role of resting-state functional magnetic resonance imaging (rs-fMRI) in detecting brain functional changes.

    METHODS: A systematic search was performed in the PubMed, Scopus, and Web of Science (WoS) databases in June 2022. Patients with head and neck cancer treated with radiotherapy and periodic rs-fMRI assessments were included. A meta-analysis was performed to determine the potential of rs-fMRI for detecting brain changes.

    RESULTS: Ten studies with a total of 513 subjects (head and neck cancer patients, n = 437; healthy controls, n = 76) were included. A significance of rs-fMRI for detecting brain changes in the temporal and frontal lobes, cingulate cortex, and cuneus was demonstrated in most studies. These changes were reported to be associated with dose (6/10 studies) and latency (4/10 studies). A strong effect size (r = 0.71, p 

  7. Wan Ibadullah WH, Yahya N, Ghazali SS, Kamaruzaman E, Yong LC, Dan A, et al.
    Rev Bras Anestesiol, 2016 Jul-Aug;66(4):363-8.
    PMID: 27157205 DOI: 10.1016/j.bjan.2016.04.007
    BACKGROUND AND OBJECTIVE: This was a prospective, randomized clinical study to compare the success rate of nasogastric tube insertion by using GlideScope™ visualization versus direct MacIntosh laryngoscope assistance in anesthetized and intubated patients.
    METHODS: Ninety-six ASA I or II patients, aged 18-70 years were recruited and randomized into two groups using either technique. The time taken from insertion of the nasogastric tube from the nostril until the calculated length of tube had been inserted was recorded. The success rate of nasogastric tube insertion was evaluated in terms of successful insertion in the first attempt. Complications associated with the insertion techniques were recorded.
    RESULTS: The results showed success rates of 74.5% in the GlideScope™ Group as compared to 58.3% in the MacIntosh Group (p=0.10). For the failed attempts, the nasogastric tube was successfully inserted in all cases using rescue techniques. The duration taken in the first attempt for both techniques was not statistically significant; Group A was 17.2±9.3s as compared to Group B, with a duration of 18.9±13.0s (p=0.57). A total of 33 patients developed complications during insertion of the nasogastric tube, 39.4% in Group A and 60.6% in Group B (p=0.15). The most common complications, which occurred, were coiling, followed by bleeding and kinking.
    CONCLUSION: This study showed that using the GlideScope™ to facilitate nasogastric tube insertion was comparable to the use of the MacIntosh laryngoscope in terms of successful rate of insertion and complications.
    KEYWORDS: Complications; Complicações; Direct laryngoscope; Laringoscopia direta; Nasogastric tube; Sonda nasogástrica; Videolaringoscópio; Videolaryngoscope
  8. Wan Ibadullah WH, Yahya N, Ghazali SS, Kamaruzaman E, Yong LC, Dan A, et al.
    Braz J Anesthesiol, 2016 Jul-Aug;66(4):363-8.
    PMID: 27343785 DOI: 10.1016/j.bjane.2014.11.013
    BACKGROUND AND OBJECTIVE: This was a prospective, randomized clinical study to compare the success rate of nasogastric tube insertion by using GlideScope™ visualization versus direct MacIntosh laryngoscope assistance in anesthetized and intubated patients.

    METHODS: Ninety-six ASA I or II patients, aged 18-70 years were recruited and randomized into two groups using either technique. The time taken from insertion of the nasogastric tube from the nostril until the calculated length of tube had been inserted was recorded. The success rate of nasogastric tube insertion was evaluated in terms of successful insertion in the first attempt. Complications associated with the insertion techniques were recorded.

    RESULTS: The results showed success rates of 74.5% in the GlideScope™ Group as compared to 58.3% in the MacIntosh Group (p=0.10). For the failed attempts, the nasogastric tube was successfully inserted in all cases using rescue techniques. The duration taken in the first attempt for both techniques was not statistically significant; Group A was 17.2±9.3s as compared to Group B, with a duration of 18.9±13.0s (p=0.57). A total of 33 patients developed complications during insertion of the nasogastric tube, 39.4% in Group A and 60.6% in Group B (p=0.15). The most common complications, which occurred, were coiling, followed by bleeding and kinking.

    CONCLUSION: This study showed that using the GlideScope™ to facilitate nasogastric tube insertion was comparable to the use of the MacIntosh laryngoscope in terms of successful rate of insertion and complications.
  9. Wan Mat WR, Yahya N, Izaham A, Abdul Rahman R, Abdul Manap N, Md Zain J
    Int J Risk Saf Med, 2014;26(2):57-60.
    PMID: 24902502 DOI: 10.3233/JRS-140611
    Acute pain service (APS) ensures provision of effective and safe postoperative pain relief. The following cases describe a potentially fatal error in managing patients who receive epidural analgesia postoperatively.
  10. Wong HS, Abdul Rahman R, Choo SY, Yahya N
    Med J Malaysia, 2012 Aug;67(4):435-7.
    PMID: 23082461 MyJurnal
    We report a rare case of an 18 year old girl with Sturge-Weber syndrome, she had extensive facial port wine stains, right bupthalmos and advanced glaucoma involving both eyes. She underwent right eye glaucoma drainage device surgery under general anaesthesia, and had a difficult intubation due to extensive angiomatous like soft tissue swelling at her upper airway. This report highlights the importance of being aware of the need for continuous follow-up in Sturge-Weber syndrome patients as this syndrome can lead to blindness due to advance glaucoma and the awareness of possible difficult intubation for this group of patients.
  11. Yahya N, Kamel NS, Malik AS
    Biomed Eng Online, 2014;13(1):154.
    PMID: 25421914 DOI: 10.1186/1475-925X-13-154
    Ultrasound imaging is a very essential technique in medical diagnosis due to its being safe, economical and non-invasive nature. Despite its popularity, the US images, however, are corrupted with speckle noise, which reduces US images qualities, hampering image interpretation and processing stage. Hence, there are many efforts made by researches to formulate various despeckling methods for speckle reduction in US images.
  12. Yahya N, Ebert MA, Bulsara M, Haworth A, Kearvell R, Foo K, et al.
    Radiat Oncol, 2014;9:282.
    PMID: 25498565 DOI: 10.1186/s13014-014-0282-7
    To assess the impact of incremental modifications of treatment planning and delivery technique, as well as patient anatomical factors, on late gastrointestinal toxicity using data from the TROG 03.04 RADAR prostate radiotherapy trial.
  13. Yahya N, Ebert MA, Bulsara M, House MJ, Kennedy A, Joseph DJ, et al.
    Radiother Oncol, 2015 Nov;117(2):277-82.
    PMID: 26476560 DOI: 10.1016/j.radonc.2015.10.003
    This study aimed to compare urinary dose-symptom correlates after external beam radiotherapy of the prostate using commonly utilised peak-symptom models to multiple-event and event-count models which account for repeated events.
  14. Yahya N, Ebert MA, Bulsara M, House MJ, Kennedy A, Joseph DJ, et al.
    Med Phys, 2016 May;43(5):2040.
    PMID: 27147316 DOI: 10.1118/1.4944738
    Given the paucity of available data concerning radiotherapy-induced urinary toxicity, it is important to ensure derivation of the most robust models with superior predictive performance. This work explores multiple statistical-learning strategies for prediction of urinary symptoms following external beam radiotherapy of the prostate.
  15. Yahya N, Ebert MA, Bulsara M, Haworth A, Kennedy A, Joseph DJ, et al.
    Radiother Oncol, 2015 Jul;116(1):112-8.
    PMID: 26163088 DOI: 10.1016/j.radonc.2015.06.011
    To identify dosimetry, clinical factors and medication intake impacting urinary symptoms after prostate radiotherapy.
  16. Yahya N, Manan HA
    World Neurosurg, 2019 Oct;130:e188-e198.
    PMID: 31326352 DOI: 10.1016/j.wneu.2019.06.027
    BACKGROUND: Diffusion tensor imaging (DTI), which visualizes white matter tracts, can be integrated to optimize intracranial radiation therapy (RT) and radiosurgery (RS) treatment planning. This study aimed to systematically review the integration of DTI for dose optimization in terms of evidence of dose improvement, clinical parameter changes, and clinical outcome in RT/RS treatment planning.

    METHODS: PubMed and Scopus electronic databases were searched based on the guidelines established by PRISMA to obtain studies investigating the integration of DTI in intracranial RT/RS treatment planning. References and citations from Google Scholar were also extracted. Eligible studies were extracted for information on changes in dose distribution, treatment parameters, and outcome after DTI integration.

    RESULTS: Eighteen studies were selected for inclusion with 406 patients (median study size, 19; range: 2-144). Dose distribution, with or without DTI integration, described changes of treatment parameters, and the reported outcome of treatment were compared in 12, 7, and 10 studies, respectively. Dose distributions after DTI integration improved in all studies. Delivery time or monitor unit was higher after integration. In studies with long-term follow-up (median, >12 months), neurologic deficits were significantly fewer in patients with DTI integration.

    CONCLUSIONS: Integrating DTI into RT/RS treatment planning improved dose distribution, with higher treatment delivery time or monitor unit as a potential drawback. Fewer neurologic deficits were found with DTI integration.

  17. Yahya N, Manan HA
    Support Care Cancer, 2021 Jun;29(6):3035-3047.
    PMID: 33040284 DOI: 10.1007/s00520-020-05808-z
    BACKGROUND: Proton therapy (PT), frequently utilised to treat paediatric brain tumour (PBT) patients, eliminates exit dose and minimises dose to healthy tissues that theoretically can mitigate treatment-related effects including cognitive deficits. As clinical outcome data are emerging, we aimed to systematically review current evidence of cognitive changes following PT of PBT.

    MATERIALS AND METHODS: We searched PubMed and Scopus electronic databases to identify eligible reports on cognitive changes following PT of PBT according to PRISMA guidelines. Reports were extracted for information on demographics and cognitive outcomes. Then, they were systematically reviewed based on three themes: (1) comparison with photon therapy, (2) comparison with baseline cognitive measures, to population normative mean or radiotherapy-naïve PBT patients and (3) effects of dose distribution to cognition.

    RESULTS: Thirteen reports (median size (range): 70 (12-144)) were included. Four reports compared the cognitive outcome between PBT patients treated with proton to photon therapy and nine compared with baseline/normative mean/radiotherapy naïve from which two reported the effects of dose distribution. Reports found significantly poorer cognitive outcome among patients treated with photon therapy compared with proton therapy especially in general cognition and working memory. Craniospinal irradiation (CSI) was consistently associated with poorer cognitive outcome while focal therapy was associated with minor cognitive change/difference. In limited reports available, higher doses to the hippocampus and temporal lobes were implicated to larger cognitive change.

    CONCLUSION: Available evidence suggests that PT causes less cognitive deficits compared with photon therapy. Children who underwent focal therapy with proton were consistently shown to have low risk of cognitive deficit suggesting the need for future studies to separate them from CSI. Evidence on the effect of dose distribution to cognition in PT is yet to mature.

  18. Yahya N, Zakariah MH
    J Nanosci Nanotechnol, 2012 Oct;12(10):8147-52.
    PMID: 23421192
    Electromagnetic (EM) waves transmitted by Horizontal Electric Dipole (HED) source to detect contrasts in subsurface resistivity termed Seabed Logging (SBL) is now an established method for hydrocarbon exploration. However, currently used EM wave detectors for SBL have several challenges including the sensitivity and its bulk size. This work exploits the benefit of superconductor technology in developing a magnetometer termed Superconducting Quantum Interference Device (SQUID) which can potentially be used for SBL. A SQUID magnetometer was fabricated using hexagon shape-niobium wire with YBa2Cu37O, (YBCO) as a barrier. The YBa2Cu37O, samples were synthesized by sol-gel method and were sintered using a furnace and conventional microwave oven. The YBCO gel was dried at 120 degrees C in air for 72 hours. It was then ground and divided into 12 parts. Four samples were sintered at 750 degrees C, 850 degrees C, 900 degrees C, and 950 degrees C for 12 hours in a furnace to find the optimum temperature. The other eight samples were sintered in a microwave with 1100 Watt (W) with a different sintering time, 5, 15, 45 minutes, 1 hour, 1 hour 15 minutes, 1 hour 30 minutes, 1 hour 45 minutes and 2 hours. A DEWAR container was designed and fabricated using fiberglass material. It was filled with liquid nitrogen (LN2) to ensure the superconducting state of the magnetometer. XRD results showed that the optimum sintering temperature for the formation of orthorhombic Y-123 phase was at 950 degrees C with the crystallite size of 67 nm. The morphology results from Field Emission Scanning Electron Microscopy (FESEM) showed that the grains had formed a rod shape with an average diameter of 60 nm. The fabricated SQUID magnetometer was able to show an increment of approximately 249% in the intensity of the EM waves when the source receiver offset was one meter apart.
  19. Yahya N, Akhtar MN, Koziol K
    J Nanosci Nanotechnol, 2012 Oct;12(10):8116-22.
    PMID: 23421187
    Magnetic nanoparticles in the hollow region of carbon nanotubes have attraction due to their changing physical electrical and magnetic properties. Nickel zinc ferrite plays an important role in many applications due to its superior magnetic properties. Ni0.8Zn0.2Fe2O4 single crystals were encapsulated in multiwall carbon nanotubes (MWCNTs). The magnetic nano crystals were prepared using a sol-gel self combustion method at the sintering temperature of 750 degrees C and were characterized by XRD, FESEM, TEM and VSM. Initial permeability, Q-factor and relative loss factor were measured by impedance vector network analyzer. XRD patterns were used for the phase identification. FESEM images show morphology and dimensions of the grains of Ni0.8Zn0.2Fe2O4 single crystals and Ni0.8Zn0.2Fe2O4 single crystals in MWCNTs. TEM images were used to investigate single crystal and encapsulation of Ni0.8Zn0.2Fe2O4 single crystals in the MWCNTs. VSM results confirmed super paramagnetic behaviour of encapsulated Ni0.8Zn0.2Fe2O4 single crystals. It was also attributed that encapsulated Ni0.8Zn0.2Fe2O4 single crystals in MWCNTs showed a higher initial permeability (51.608), Q-factor (67.069), and low loss factor (0.0002) as compared to Ni0.8Zn0.2Fe2O4 single crystals. The new encapsulated Ni0.8Zn0.2Fe2O4 single crystals in the MWCNTs may have potential applications in electronic and medical industries.
  20. Yahya N, Akhtar MN, Nasir N, Shafie A, Jabeli MS, Koziol K
    J Nanosci Nanotechnol, 2012 Oct;12(10):8100-9.
    PMID: 23421185
    In seabed logging the magnitude of electromagnetic (EM) waves for the detection of a hydrocarbon reservoir in the marine environment is very important. Having a strong EM source for exploration target 4000 m below the sea floor is a very challenging task. A new carbon nanotubes (CNT) fibres/aluminium based EM transmitter is developed and NiZn ferrite as magnetic feeders was used in a scaled tank to evaluate the presence of oil. Resistive scaled tank experiments with a scale factor of 2000 were carried out. X-ray Diffraction (XRD), Raman Spectroscopy and Field Emission Scanning Electron Microscope (FESEM) were done to characterize the synthesized magnetic feeders. Single phase Ni0.76Mg0.04Zn0.2Fe2O4, obtained by the sol-gel method and sintered at 700 degrees C in air, has a [311] major peak. FESEM results show nanoparticles with average diameters of 17-45 nm. Samples which have a high Q-factor (approximately 50) was used as magnetic feeders for the EM transmitter. The magnitude of the EM waves of this new EM transmitter increases up to 400%. A curve fitting method using MATLAB software was done to evaluate the performance of the new EM transmitter. The correlation value with CNT fibres/aluminium-NiZnFe2O4 base transmitter shows a 152.5% increase of the magnetic field strength in the presence of oil. Modelling of the scale tank which replicates the marine environment was done using the Finite Element Method (FEM). In conclusion, FEM was able to delineate the presence of oil with greater magnitude of E-field (16.89%) and the B field (4.20%) due to the new EM transmitter.
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