Displaying publications 61 - 80 of 133 in total

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  1. Al-Rahbi B, Zakaria R, Othman Z, Hassan A, Ahmad AH
    Int Sch Res Notices, 2014;2014:521065.
    PMID: 27379299 DOI: 10.1155/2014/521065
    The present study aims to evaluate the antioxidant and anxiolytic-like effect of Tualang honey in stressed ovariectomized (OVX) rats. The animals were divided into; (i) nonstressed sham-operated control rats, (ii) sham-operated control rats exposed to stress, (iii) nonstressed OVX rats, (iv) OVX rats exposed to stress, (v) OVX rats exposed to stress and treated with 17 β-oestradiol (E2) (20 μg daily, sc), and (vi) OVX rats exposed to stress and treated with Tualang honey (0.2 g/kg body weight, orally). The open field test was used to evaluate the anxiety-like behaviour and ELISA kits were used to measure oxidant/antioxidant status of the brain homogenates. The result showed that anxiety-like behavior was significantly increased in stressed OVX compared to other groups, and administering either E2 or Tualang honey significantly decreased anxiety-like behaviour in stressed OVX rats. The levels of malondialdehyde (MDA) and protein carbonyl (PCO) were significantly decreased while the levels/activities of superoxide dismutase (SOD), glutathione S-transferases (GST), glutathione peroxidase (GPx), and glutathione reductase (GR) were significantly increased in the brain homogenates of treated stressed OVX groups compared to untreated stressed OVX. In conclusion, Tualang honey has protective effects against brain oxidative stress and may be useful alternative anxiolytic agent especially for postmenopausal women.
  2. Munjir N, Othman Z, Zakaria R, Shafin N, Hussain NA, Desa AM, et al.
    EXCLI J, 2015;14:801-8.
    PMID: 26600750 DOI: 10.17179/excli2015-280
    This study aims to develop two alternate forms for Malay version of Auditory Verbal Learning Test (MAVLT) and to determine their equivalency and practice effect. Ninety healthy volunteers were subjected to the following neuropsychological tests at baseline, and at one month interval according to their assigned group; group 1 (MAVLT - MAVLT), group 2 (MAVLT - Alternate Form 1 - Alternate Form 1), and group 3 (MAVLT - Alternate Form 2 - Alternate Form 2). There were no significant difference in the mean score of all the trials at baseline among the three groups, and most of the mean score of trials between MAVLT and Alternate Form 1, and between MAVLT and Alternate Form 2. There was significant improvement in the mean score of each trial when the same form was used repeatedly at the interval of one month. However, there was no significant improvement in the mean score of each trial when the Alternate Form 2 was used during repeated neuropsychological testing. The MAVLT is a reliable instrument for repeated neuropsychological testing as long as alternate forms are used. The Alternate Form 2 showed better equivalency to MAVLT and less practice effects.
  3. Aziz CB, Omar N, Abdullah WZ, Jalil RA, Nik WS, Zakaria R
    N Am J Med Sci, 2014 Aug;6(8):377-82.
    PMID: 25210670 DOI: 10.4103/1947-2714.139286
    Obese subjects are at risk of multiple comorbidities including stroke and coronary heart disease (CHD), which is partly due to disturbances in the hemostatic system.
  4. Al-Rahbi B, Zakaria R, Othman Z, Hassan A, Muthuraju S, Wan Mohammad WM
    Biomed Res Int, 2013;2013:493643.
    PMID: 23841073 DOI: 10.1155/2013/493643
    This study aims to compare the effects of social instability stress on memory and anxiety- and depressive-like behaviour between sham-operated controls and ovariectomised (OVX) rats. Forty adult female Sprague-Dawley rats (8 weeks old) were randomly divided into four groups, (n = 10 per group). These were non-stressed sham-operated control rats, stressed sham-operated control rats, non-stressed OVX rats, and stressed OVX rats. The rats were subjected to social instability stress procedure for 15 days. Novel object recognition, open field, and forced swim tests were conducted after the stress procedure. Serum estradiol, ACTH and corticosterone levels were measured using commercially available ELISA kits. Lower serum estradiol level and uterine weight with higher weight gain were observed in OVX rats compared to sham-operated controls. Serum ACTH, and corticosterone levels were higher in stressed compared to non-stressed groups. Memory deficit and anxiety- and depressive-like behaviour were significantly increased in stressed compared to non-stressed OVX rats but these changes were not seen in sham-operated controls. These results suggest that the high circulating corticosterone acts synergistically with low circulating estradiol to exert negative effects on mood and memory function.
  5. Selamat R, Zain F, Raib J, Zakaria R, Marzuki MS, Ibrahim TF
    J Am Coll Nutr, 2011 Dec;30(6):522-8.
    PMID: 22331687
    OBJECTIVE: To study the validity of the visual clinical assessment of weight relative to length and length relative to age as compared to the World Health Organization (WHO) 2006 standard and National Center for Health Statistics (NCHS) 1977 reference in asssessing the physical growth of children younger than 1 year.

    MATERIALS AND METHODS: A prospective cohort study was carried out among 684 infants attending goverment health clinics in 2 states in Malaysia. Body weight, length, and clinical assessment were measured on the same day for 9 visits, scheduled every month until 6 months of age and every 2 months until 12 months of age. All of the 3 z-scores for weight for age (WAZ), length for age (HAZ), and weight for length (WHZ) were calculated using WHO Anthro for Personal Computers software.

    RESULTS: The average sensitivity and specificity for the visual clinical assessment for the detection of thinness were higher using the WHO 2006 standard as compared with using NCHS 1977. However, the overall sensitivity of the visual clinical assessment for the detection of thin and lean children was lower from 1 month of age until a year as compared with the WHO 2006 standard and NCHS 1977 reference. The positive predictive value (PPV) for the visual clinical assessment versus the WHO 2006 standard was almost doubled as compared with the PPV of visual clinical assessment versus the NCHS 1977 reference. The overall average sensitivity, specificity, PPV, and negative predictive value for the detection of stunting was higher for visual clinical assessment versus the WHO 2006 standard as compared with visual clinical assessment versus the NCHS 1977 reference.

    CONCLUSION: The sensitivity and specificity of visual clinical assessment for the detection of wasting and stunting among infants are better for the WHO 2006 standard than the NCHS 1977 reference.

  6. Salmi AA, Zaki NM, Zakaria R, Nor Aliza AG, Rasool AH
    VASA, 2012 Mar;41(2):96-104.
    PMID: 22403127 DOI: 10.1024/0301-1526/a000171
    This study aims to determine whether gestational diabetes mellitus (GDM) is associated with increased arterial stiffness, inflammatory and pro-atherogenic markers compared to age matched controls.
  7. Cheong YK, Lim KS, Lim WH, Chong WY, Zakaria R, Ahmad H
    Rev Sci Instrum, 2011 Aug;82(8):086115.
    PMID: 21895293 DOI: 10.1063/1.3627374
    Tapered fibre tips fabricated using mechanical polishing method is studied. The fibre tips are formed by sequential polishing flat-ended single mode fibres with decreasing aluminium oxide polishing film grit size. Based on the proposed technique, tapered fibre tips with cone angle ranging from 30° to 130° are fabricated by controlling the polishing angle. Besides the variety of cone angle, considerable smoothness of the fibre tip surface may assist in good metal coating and hence a well-defined aperture can be obtained. In addition, this paper presents a two-step hybrid fabrication method combining the proposed polishing method with chemical etching method to increase the possible fibre tip cone angles achievable by chemical etching method.
  8. Othman Z, Shafin N, Zakaria R, Hussain NH, Mohammad WM
    Menopause, 2011 Nov;18(11):1219-24.
    PMID: 21926932 DOI: 10.1097/gme.0b013e31821e2044
    The aim of this study was to evaluate the verbal learning and memory performance of postmenopausal women who received tualang honey (Agro Mas) in comparison with women receiving estrogen plus progestin therapy and untreated controls.
  9. Haron MN, D'Souza UJ, Jaafar H, Zakaria R, Singh HJ
    Fertil. Steril., 2010 Jan;93(1):322-4.
    PMID: 19709655 DOI: 10.1016/j.fertnstert.2009.07.995
    Daily intraperitoneal injection of 5-30 microg/kg body weight of leptin for 42 days to adult rats decreases sperm count and increases the fraction of abnormal sperm.
  10. Safdar A, Zakaria R, Aziz CBA, Rashid U, Azman KF
    Biogerontology, 2020 04;21(2):203-216.
    PMID: 31792648 DOI: 10.1007/s10522-019-09854-x
    One of the most significant hallmarks of aging is cognitive decline. D-galactose administration may impair memory and mimic the effects of natural aging. In this study, the efficiency of goat milk to protect against memory decline was tested. Fifty-two male Sprague-Dawley rats were randomly divided into four groups: (i) control group, (ii) goat milk treated group, (iii) D-galactose treated group, and (iv) goat milk plus D-galactose treated group. Subcutaneous injections of D-galactose at 120 mg/kg and oral administrations of goat milk at 1 g/kg were chosen for the study. Goat milk and D-galactose were administered concomitantly for 6 weeks, while the control group received saline. After 6 weeks, novel object recognition and T-maze tests were performed to evaluate memory of rats. Following behavioral tests, the animals were sacrificed, and right brain homogenates were analyzed for levels of lipid peroxidation, antioxidant enzymes and neurotrophic factors. The left brain hemisphere was used for histological study of prefrontal cortex and hippocampus. There was a significant memory impairment, an increase in oxidative stress and neurodegeneration and a reduction in antioxidant enzymes and neurotrophic factors levels in the brain of D-galactose treated rats compared to controls. Goat milk treatment attenuated memory impairment induced by D-galactose via suppressing oxidative stress and neuronal damage and increasing neurotrophic factors levels, thereby suggesting its potential role as a geroprotective food.
  11. Siew-Keah L, Sundaram A, Sirajudeen KN, Zakaria R, Singh HJ
    J Physiol Biochem, 2014 Mar;70(1):73-9.
    PMID: 23975651 DOI: 10.1007/s13105-013-0282-3
    Antenatal and postnatal environments are hypothesised to influence the development of hypertension. This study investigates the synergistic effect of cross-fostering and melatonin supplementation on the development of hypertension and renal glutathione system in spontaneously hypertensive rats (SHR). In one experiment, 1-day-old male SHR pups were fostered to either SHR (shr-SHR) or Wistar-Kyoto rats, (shr-WKY). In a concurrent experiment, SHR dams were given melatonin in drinking water (10 mg/kg body weight) from day 1 of pregnancy. Immediately following delivery, 1-day-old male pups were fostered either to SHR (Mel-shr-SHR) or WKY (Mel-shr-WKY) dams receiving melatonin supplementation until weaning on day 21. Upon weaning, melatonin supplementation was continued to these pups until the age of 16 weeks. Systolic blood pressures (SBP) were recorded at the age of 4, 6, 8, 12 and 16 weeks. Renal antioxidant activities were measured. Mean SBP of shr-WKY, Mel-shr-SHR and Mel-shr-WKY was significantly lower than that in shr-SHR until the age of 8 weeks. At 12 and 16 weeks of age, mean SBP of Mel-shr-WKY was lower than those in non-treated shr-SHR and shr-WKY pups but was not significantly different from that in Mel-shr-SHR. Renal glutathione peroxidase (GPx) and glutathione S-transferase (GST) activities were significantly higher in Mel-shr-SHR and Mel-shr-WKY at 16 weeks of age. It appears that combination of cross-fostering and melatonin supplementation exerts no synergistic effect on delaying the rise in blood pressure in SHR. The elevated GPx and GST activities are likely to be due to the effect of melatonin supplementation.
  12. Lee SK, Sirajudeen KN, Sundaram A, Zakaria R, Singh HJ
    J Physiol Biochem, 2011 Jun;67(2):249-57.
    PMID: 21210316 DOI: 10.1007/s13105-010-0070-2
    Although melatonin lowers blood pressure in spontaneously hypertensive rats (SHR), its effect following antenatal and postpartum supplementation on the subsequent development of hypertension in SHR pups remains unknown. To investigate this, SHR dams were given melatonin in drinking water (10 mg/kg body weight/day) from day 1 of pregnancy until day 21 postpartum. After weaning, a group of male pups continued to receive melatonin till the age of 16 weeks (Mel-SHR), while no further melatonin was given to another group of male pups (Maternal-Mel-SHR). Controls received plain drinking water. Systolic blood pressure (SBP) was measured at 4, 6, 8, 12 and 16 weeks of age, after which the kidneys were collected for analysis of antioxidant enzyme profiles. SBP was significantly lower till the age of 8 weeks in Maternal-Mel-SHR and Mel-SHR than that in the controls, after which no significant difference was evident in SBP between the controls and Maternal-Mel-SHR. SBP in Mel-SHR was lower than that in controls and Maternal-Mel-SHR at 12 and 16 weeks of age. Renal glutathione peroxidase (GPx) and glutathione s-transferase (GST) activities, levels of total glutathione and relative GPx-1 protein were significantly higher in Mel-SHR. GPx protein was however significantly higher in Mel-SHR. No significant differences were evident between the three groups in the activities of superoxide dismutase, catalase and glutathione reductase. In conclusion, it appears that while antenatal and postpartum melatonin supplementation decreases the rate of rise in blood pressure in SHR offspring, it however does not alter the tendency of offspring of SHR to develop hypertension.
  13. Abd Aziz CB, Ahmad Suhaimi SQ, Hasim H, Ahmad AH, Long I, Zakaria R
    J Integr Med, 2019 Jan;17(1):66-70.
    PMID: 30591413 DOI: 10.1016/j.joim.2018.12.002
    OBJECTIVE: This study was done to determine whether Tualang honey could prevent the altered nociceptive behaviour, with its associated changes of oxidative stress markers and morphology of the spinal cord, among the offspring of prenatally stressed rats.

    METHODS: Pregnant rats were divided into three groups: control, stress, and stress treated with Tualang honey. The stress and stress treated with Tualang honey groups were subjected to restraint stress from day 11 of pregnancy until delivery. Ten week old male offspring (n = 9 from each group) were given formalin injection and their nociceptive behaviours were recorded. After 2 h, the rats were sacrificed, and their spinal cords were removed to assess oxidative stress activity and morphology. Nociceptive behaviour was analysed using repeated measures analysis of variance (ANOVA), while the levels of oxidative stress parameters and number of Nissl-stained neurons were analysed using a one-way ANOVA.

    RESULTS: This study demonstrated that prenatal stress was associated with increased nociceptive behaviour, changes in the oxidative stress parameters and morphology of the spinal cord of offspring exposed to prenatal stress; administration of Tualang honey reduced the alteration of these parameters.

    CONCLUSION: This study provides a preliminary understanding of the beneficial effects of Tualang honey against the changes in oxidative stress and neuronal damage in the spinal cord of the offspring of prenatally stressed rats.

  14. Zakaria R, Zainuddin NAM, Leong TC, Rosli R, Rusdi MF, Harun SW, et al.
    Micromachines (Basel), 2019 Jul 11;10(7).
    PMID: 31336745 DOI: 10.3390/mi10070465
    In this paper, we report the effects of a side-polished fiber (SPF) coated with titanium (Ti) films in different thicknesses, namely 5 nm, 13 nm, and 36 nm, protected by a thin layer of transition metal dichalcogenides (TMDCs) such as molybdenum disulfide (MoS2) and tungsten disulfide (WS2), which provide ultra-sensitive sensor-based surface plasmon resonance (SPR) covering from the visible to mid-infrared region. The SPF deposited with Ti exhibits strong evanescent field interaction with the MoS2 and WS2, and good optical absorption, hence resulting in high-sensitivity performance. Incremental increases in the thickness of the Ti layer contribute to the enhancement of the intensity of transmission with redshift and broad spectra. The findings show that the optimum thickness of Ti with 36 nm combined with MoS2 causes weak redshifts of the longitudinal localized surface plasmon resonance (LSPR) mode, while the same thickness of Ti with WS2 causes large blueshifts. The redshifts are possibly due to a reduced plasmon-coupling effect with the excitonic region of MoS2. The observed blueshifts of the LSPR peak position are possibly due to surface modification between WS2 and Ti. Changing the relative humidity from 58% to 88% only elicited a response in Ti/MoS2. Thus, MoS2 shows more sensitivity on 36-nm thickness of Ti compared with WS2. Therefore, the proposed fiber-optic sensor with integration of 2D materials is capable of measuring humidity in any environment.
  15. Qurash MT, Yaacob NY, Azuan N, Khaleel YS, Zakaria R
    J Med Ultrasound, 2018 06 18;26(4):210-214.
    PMID: 30662153 DOI: 10.4103/JMU.JMU_40_18
    Interventional radiology procedures are becoming more challenging over time; thus, there is a need for excellent and reliable training methods. Training on live patients is neither safe nor an ethical solution. Alternatives are many and varied, but the most popular is ultrasound guided simulators. This report shows how a simple, homemade, low-cost phantom material, and construction modules can provide several advantages over ordinary gelatin phantoms. A new layering technique and target synthesis are described for the biopsy phantom, including tips on decreasing the needle pass artifact as well as controlling the mixture echogenicity.
  16. Zakaria R, Harif N, Al-Rahbi B, Aziz CBA, Ahmad AH
    Oman Med J, 2019 Jan;34(1):44-48.
    PMID: 30671183 DOI: 10.5001/omj.2019.07
    Objectives: Overweight and obesity are known to cause various patterns of alteration to the pulmonary function test (PFT) parameters. We sought to investigate gender differences in PFT parameters and examine the relationship between body mass index (BMI) and PFT parameters.
    Methods: We conducted a retrospective study of 126 patients referred for a PFT by various medical specialties between January and December 2015. PFT was measured using spirometry, and BMI was calculated using Quetelet's index.
    Results: Female patients exhibited lower mean values for all PFT parameters compared to male patients. The forced vital capacity (FVC)% predicted was less than 80% for all patients while the ratio of forced expiratory volume in 1 second (FEV1)/FVC was higher with increased BMI. BMI was positively correlated with peak expiratory flow in all patients, and with FEV1/FVC ratio in males but not in females.
    Conclusions: In our studied population, males exhibited higher mean values of PFT parameters than females. Increased BMI may be associated with a restrictive pattern on spirometry.
  17. Cox-Singh J, Pomrehn AS, Rahman HA, Zakaria R, Miller AO, Singh B
    Int J Parasitol, 1999 May;29(5):717-21.
    PMID: 10404266
    In the absence of a suitable Brugia malayi antigen detection assay, PCR remains one of the more sensitive alternatives to Giemsa-stained thick blood films for B. malayi detection. The need for refrigerated storage and transportation of blood has limited the use of PCR for large-scale epidemiology studies in remote endemic areas. Here we report simple finger-prick blood-spot collection, a one-tube DNA template extraction method and the development of a B. malayi-specific nested PCR assay. The assay was tested on 145 field samples and was positive for all 30 microscopy-positive samples and for an additional 13 samples which were microscopy-negative.
  18. Zulkipli NN, Zakaria R, Long I, Abdullah SF, Muhammad EF, Wahab HA, et al.
    Molecules, 2020 Sep 02;25(17).
    PMID: 32887218 DOI: 10.3390/molecules25173991
    Natural products remain a popular alternative treatment for many ailments in various countries. This study aimed to screen for potential mammalian target of rapamycin (mTOR) inhibitors from Malaysian natural substance, using the Natural Product Discovery database, and to determine the IC50 of the selected mTOR inhibitors against UMB1949 cell line. The crystallographic structure of the molecular target (mTOR) was obtained from Protein Data Bank, with Protein Data Bank (PDB) ID: 4DRI. Everolimus, an mTOR inhibitor, was used as a standard compound for the comparative analysis. Computational docking approach was performed, using AutoDock Vina (screening) and AutoDock 4.2.6 (analysis). Based on our analysis, asiaticoside and its derivative, asiatic acid, both from Centella asiatica, revealed optimum-binding affinities with mTOR that were comparable to our standard compound. The effect of asiaticoside and asiatic acid on mTOR inhibition was validated with UMB1949 cell line, and their IC50 values were 300 and 60 µM, respectively, compared to everolimus (29.5 µM). Interestingly, this is the first study of asiaticoside and asiatic acid against tuberous sclerosis complex (TSC) disease model by targeting mTOR. These results, coupled with our in silico findings, should prompt further studies, to clarify the mode of action, safety, and efficacy of these compounds as mTOR inhibitors.
  19. Khor SP, Yeow LC, Poobathy R, Zakaria R, Chew BL, Subramaniam S
    Biotechnol Rep (Amst), 2020 Jun;26:e00448.
    PMID: 32368510 DOI: 10.1016/j.btre.2020.e00448
    A droplet-vitrification cryopreservation protocol has been successfully developed for Aranda Broga Blue orchid hybrid using protocorm-like bodies (PLBs). However, maximum growth regeneration percentage was recorded at 5% only based on previous report. Thus, to improve growth recovery of cryopreserved PLBs, cryopreservation stages were supplemented with ascorbic acid, tested at 50, 100 and 150 mg/L. However, results demonstrated that exogenous ascorbic acid was not favorable in regeneration of cryopreserved explants (maximum value of 1.67 % with 50 mg/L ascorbic acid supplementation). Total soluble protein and various antioxidant enzyme activities such as catalase (CAT), superoxide dismutase (SOD) and ascorbate peroxidase (APX) were evaluated after each cryopreservation stages in conjunction with the application of exogenous ascorbic acid. Addition of antioxidant must be carefully evaluated and its application may not guarantee successful growth recovery. RAPD and SCoT molecular analysis confirmed the genetic stability of regenerated cryopreserved PLBs as no polymorphism was detected compared to control PLBs culture.
  20. 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.

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