Displaying publications 1 - 20 of 59 in total

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  1. Does facial appearance of dentofacial deformity influence the need for orthognathic surgery: The Malaysian perception
    Abdul Halim Chong FH, Md Salleh SN, Abu Bakar N, Ismail IN
    Singapore Dent J, 2019 12;39(1):41-52.
    PMID: 32910746 DOI: 10.1142/S2214607519500044
    Aim: This study evaluates perception toward facial appearance in dentofacial deformity and the need for orthognathic surgery among the public with and without dental backgrounds. Materials and Methods: A questionnaire consisting of 12 facial photographs of cases with dentofacial deformity or malocclusion in varying severity was used. A hundred individuals were selected to answer the questionnaire. The perception of facial appearance (FAS), treatment need score (TNS), and knowledge regarding dentofacial deformity were used for the evaluation. Results: Significant differences were found between dental and non-dental when the respondents' knowledge in all the questionnaire items ([Formula: see text].05) was assessed. However, no significant difference was found in the mean of FAS and TNS in all the presented cases (normal, borderline, severe). Pearson correlation between perceived FAS and TNS was statistically negative for severe and normal cases, whereby a decrease in FAS for severe cases showed an increase in TNS, and an increase in FAS for normal cases showed a decrease in TNS. Conclusion: Respondents with dental background had sound knowledge of dentofacial deformity. A poorly attractive respondent with dentofacial deformity showed a greater need for orthognathic surgery.
  2. Comparative study of chemically synthesized and low temperature bio-inspired Musa acuminata peel extract mediated zinc oxide nanoparticles for enhanced visible-photocatalytic degradation of organic contaminants in wastewater treatment
    Abdullah FH, Abu Bakar NHH, Abu Bakar M
    J Hazard Mater, 2021 03 15;406:124779.
    PMID: 33338763 DOI: 10.1016/j.jhazmat.2020.124779
    Zinc oxide (ZnO) photocatalysts were successfully synthesized via chemical and green, environmentally-benign methods. The work highlights the valorization of banana peel (BP) waste extract as the reducing and capping agents to produce pure, low temperature, highly crystalline, and effective ZnO nanoparticles with superior photocatalytic activities for the removal of hazardous Basic Blue 9 (BB9), crystal violet (CV), and cresol red (CR) dyes in comparison to chemically synthesized ZnO. Their formation and morphologies were verified by various optical spectroscopic and electron microscopic techniques. XRD results revealed that the biosynthesized ZnO exhibited 15.3 nm crystallite size when determined by Scherrer equation, which was smaller than the chemically synthesized ZnO. The FTIR spectra confirmed the presence of biomolecules in the green-mediated catalyst. EDX and XPS analyses verified the purity and chemical composition of ZnO. Nitrogen sorption analysis affirmed the high surface area of bio-inspired ZnO. Maximum removal efficiencies were achieved with 30 mg green ZnO catalyst, 2.0 × 10-5 M BB9 solution, alkaline pH 12, and irradiation time 90 min. Green-mediated ZnO showed superior photodegradation efficiency and reusability than chemically synthesized ZnO. Therefore, this economical, environment-friendly photocatalyst is applicable for the removal of organic contaminants in wastewater treatment under visible light irradiation.
  3. Fulltext Imaging of Osteo-odontokeratoprosthesis(OOKP) Using Multidetector Computed Tomography: A UKMMC Experience
    Abu Bakar N, Lee CL
    Med J Malaysia, 2013;68(1):73-5.
    PMID: 23466774
    Osteo-odontokeratoprosthesis (OOKP) surgery is a technique used to replace damaged cornea in blind patients for whom cadaveric transplantation is not feasible. OOKP surgery is a complex procedure requiring lifetime follow-up. The preservation of the osteo-odontolamina is the vital feature in maintaining the stability of the OOKP. Early detection of lamina resorption enables early prophylactic measures to be taken and prevent resorption-related complications. This case illustrates the radiological findings of the first OOKP surgery in Malaysia and the role of multidetector computed tomography (MDCT) in postoperative management of OOKP surgery.
  4. Imaging of an atypical pericardial cyst
    Abu Bakar N, Abdul Aziz YF, Singh Sandhu R, Fadzli F, Yaakub NA, Krishnasamy S, et al.
    Heart Lung Circ, 2013 Apr;22(4):305-8.
    PMID: 22921797 DOI: 10.1016/j.hlc.2012.07.016
    Pericardial cysts are uncommon mediastinal lesions that are usually congenital in origin. Patients are usually asymptomatic and the cysts are generally discovered on routine radiography for unrelated purposes. This case illustrates a symptomatic presentation of a haemorrhagic pericardial cyst in which radiographic, echocardiographic and multislice (MRI and CT) imaging were performed. The imaging findings were not typical of pericardial cysts leading to a diagnostic quandary despite the varied imaging techniques. In conclusion, it is important to appreciate that the imaging findings of pericardial cysts can be varied. Radiologists and clinicians alike should be aware of this variability.
  5. Protein homeostasis, regulation of energy production and activation of DNA damage-repair pathways are involved in the heat stress response of Pseudogymnoascus spp
    Abu Bakar N, Lau Yii Chung B, Smykla J, Karsani SA, Alias SA
    Environ Microbiol, 2021 Sep 16.
    PMID: 34528369 DOI: 10.1111/1462-2920.15776
    Proteome changes can be used as an instrument to measure the effects of climate change, predict the possible future state of an ecosystem and the direction in which is headed. In this study, proteomic and GO functional enrichment analysis of six Pseudogymnoascus spp. isolated from various global biogeographical regions were carried out to determine their response to heat stress. In total, 2,122 proteins were identified with high confidence. Comparative quantitative analysis showed that changes in proteome profiles varied greatly between isolates from different biogeographical regions. Although the identities of the proteins that changed varied between the different regions, the functions they governed were similar. Gene Ontology analysis showed enrichment of proteins involved in multiple protective mechanisms, including the modulation of protein homeostasis, regulation of energy production, and activation of DNA damage and repair pathways. Our proteomic analysis did not show any clear relationship between protein changes and the strains' biogeographical origins. This article is protected by copyright. All rights reserved.
  6. Fulltext Measuring pH of the Plasmodium falciparum digestive vacuole by flow cytometry
    Abu Bakar N
    Trop Biomed, 2015 Sep;32(3):485-93.
    PMID: 26695209 MyJurnal
    Studies show that the pH of the malaria parasite's digestive vacuole (DV) plays a key role in the physiological functions of this organelle and antimalarial drug accumulation, and yet is technically difficult to measure. In this study, a flow cytometry-based technique was developed to measure the DV pH using a ratiometric pH indicator, FITC-dextran loaded into the DV of saponin-permeabilized parasites. To calculate the DV pH, a standard pH calibration curve was generated by incubating the saponin-permeabilized cells in buffers with different pH in the presence of an ionophore, CCCP. The measured average pH of the DV was 5.27 ± 0.03 that is approximately the same in the parasites observed microscopically by Hayward et al. (2006) (5.50 ± 0.14) using the same probe. The removal of glucose from the medium, causing a rapid depletion of parasite ATP, resulted in an alkalization of the DV. The DV was reacidified upon restoration of glucose to the medium. This technique provides a rapid, simple and quantitative measurement of the DV pH on a large number of cells. It will also be useful in future attempts to evaluate the effect of antimalarial drugs (i.e. chloroquine and artemisinin-based drugs) in pH changes of the DV.
  7. Fulltext The comprehension and production of Wh- questions among Malay children with developmental language disorders: Climbing the syntactic tree
    Abu Bakar N, Smith G, Razak RA, Garraffa M
    Front Psychol, 2022;13:948992.
    PMID: 36389519 DOI: 10.3389/fpsyg.2022.948992
    This study is an investigation of both comprehension and production of Wh- questions in Malay-speaking children with a developmental language disorder (DLD). A total of 15 Malay children with DLD (ages 7;0-9;11 years) were tested on a set of Wh- questions (who subject and object, which subject and object), comparing their performance with two control groups [15 age-matched typically developing (TD) children and 15 younger TD language-matched children]. Malay children with DLD showed a clear asymmetry in comprehension of Wh- questions, with a selective impairment for which NP questions compared with who questions. Age-matched controls performed at ceiling in all Wh- questions, while the language-matched group reported a subject/object asymmetry selective for the which NP, as reported in other languages. In production, both children with DLD and younger children showed a preference for questions with in situ Wh- elements, a structure that is allowed in colloquial Malay, but which is not produced by the age-matched TD group. Several non-adult-like strategies were adopted particularly by the children with DLD to avoid complex sentences, including substitution with yes/no echo questions, production of the wrong Wh- question, and use of a generic Wh- element. The study provides an insight on the mastery of Wh- questions in both typical Malay children and children with DLD. Implications for the definition of a clinical marker for DLD in a free word order language with Wh- in situ option will be discussed.
  8. Evaluation of the neurotoxic effects of chronic embryonic exposure with inorganic mercury on motor and anxiety-like responses in zebrafish (Danio rerio) larvae
    Abu Bakar N, Mohd Sata NS, Ramlan NF, Wan Ibrahim WN, Zulkifli SZ, Che Abdullah CA, et al.
    Neurotoxicol Teratol, 2017 Jan-Feb;59:53-61.
    PMID: 27919701 DOI: 10.1016/j.ntt.2016.11.008
    Chronic exposure to mercury (Hg) can lead to cumulative impairments in motor and cognitive functions including alteration in anxiety responses. Although several risk factors have been identified in recent year, little is known about the environmental factors that either due exposure toward low level of inorganic mercury that may led to the developmental disorders. The present study investigated the effects of embryonic exposure of mercury chloride on motor function and anxiety-like behavior. The embryo exposed to 6 different concentrations of HgCl2 (7.5, 15, 30, 100, 125, 250nM) at 5hpf until hatching (72hpf) in a semi-static condition. The mortality rate increased in a dose dependent manner where the chronic embryonic exposure to 100nM decreased the number of tail coiling, heartbeat, and swimming activity. Aversive stimulus was used to examine the effects of 100nM interferes with the development of anxiety-related behavior. No elevation in both thigmotaxis and avoidance response of 6dpf larvae exposed with 100nM were found. Biochemical analysis showed HgCl2 exposure affects proteins, lipids, carbohydrates and nucleic acids of the zebrafish larvae. These results showed that implication of HgCl2 on locomotor and biochemical defects affects motor performance and anxiety-like responses. Yet, the potential underlying mechanisms these responses need to be further investigated which is crucial to prevent potential hazards on the developing organism due to neurotoxicant exposure.
  9. Fulltext Direct deposition of silver nanoplates on quartz surface by sequence pre-treatment hydroxylation and silanisation
    Abu Bakar N, Mat Salleh M, Ali Umar A, Shapter JG
    MethodsX, 2017;4:486-491.
    PMID: 29201649 DOI: 10.1016/j.mex.2017.11.008
    Silver nanoparticles deposited on quartz substrates are widely used as SERS substrates. The nanoparticles can be deposited directly from colloidal solution by dipping technique. However, the adhesion of the particles on the quartz surface is very poor. Normally the substrate is pre-treated with hydroxylation or silanisation process. In this paper, we have demonstrated that the application of the sequence pre-treatment hydroxylation and silanisation have improved the density of silver nanoplates desposited on the quartz surface. •Sequence hydroxylation and silanisation pre-treatment assists the deposition of the nanoplate on the surface.•Various immersion times of the quartz surface into the colloidal nanoplates determined size distributions and density surface of the nanoplates on the surface.
  10. Fulltext Clinical glycomics for the diagnosis of congenital disorders of glycosylation
    Abu Bakar N, Lefeber DJ, van Scherpenzeel M
    J Inherit Metab Dis, 2018 May;41(3):499-513.
    PMID: 29497882 DOI: 10.1007/s10545-018-0144-9
    Clinical glycomics comprises a spectrum of different analytical methodologies to analyze glycan structures, which provides insights into the mechanisms of glycosylation. Within clinical diagnostics, glycomics serves as a functional readout of genetic variants, and can form a basis for therapy development, as was described for PGM1-CDG. Integration of glycomics with genomics has resulted in the elucidation of previously unknown disorders of glycosylation, namely CCDC115-CDG, TMEM199-CDG, ATP6AP1-CDG, MAN1B1-CDG, and PGM1-CDG. This review provides an introduction into protein glycosylation and presents the different glycomics methodologies ranging from gel electrophoresis to mass spectrometry (MS) and from free glycans to intact glycoproteins. The role of glycomics in the diagnosis of congenital disorders of glycosylation (CDG) is presented, including a diagnostic flow chart and an overview of glycomics data of known CDG subtypes. The review ends with some future perspectives, showing upcoming technologies as system wide mapping of the N- and O-glycoproteome, intact glycoprotein profiling and analysis of sugar metabolism. These new advances will provide additional insights and opportunities to develop personalized therapy. This is especially true for inborn errors of metabolism, which are amenable to causal therapy, because interventions through supplementation therapy can directly target the pathogenesis at the molecular level.
  11. Fulltext Silver nanostar films for surface-enhanced Raman spectroscopy (SERS) of the pesticide imidacloprid
    Abu Bakar N, Shapter JG
    Heliyon, 2023 Mar;9(3):e14686.
    PMID: 36994401 DOI: 10.1016/j.heliyon.2023.e14686
    Strategies for synthetic control of anisotropic metal nanostructures have grown in recent years in part due to their great potential for application as surface-enhanced Raman scattering (SERS) sensing substrates. It has been shown that SERS using silver substrates is a powerful tool for identification and qualification of trace chemical analysis on the basis of their unique molecular vibrations. In this work, we synthesized star-shaped silver nanostructures and fabricated SERS substrates to use the SERS enhancement of the Raman signal to detect neonicotinoid pesticides. These silver nanostar substrates were prepared by assembling the nanostar particles on a glass substrate surface using a self-assembly technique with various layers of silver nanostars film. The silver nanostar distribution on the solid substrate surface was found to have good reproducibility, reusability and were a stable SERS substrate giving SERS enhancements for pesticide detection at concentrations as low as 10-6 mg/ml. The distribution of these silver nanostars on the surface allowed excellent reproducibility of the detection with a low relative standard derivation (RSD) of SERS intensity of 8%. This work potentially builds a platform for an ultrasensitive detector where samples can be probed with little to no pre-processing and a range of pollutants can be detected at very low levels.
  12. Fulltext Fungal survival under temperature stress: a proteomic perspective
    Abu Bakar N, Karsani SA, Alias SA
    PeerJ, 2020;8:e10423.
    PMID: 33362961 DOI: 10.7717/peerj.10423
    BACKGROUND: Increases in knowledge of climate change generally, and its impact on agricultural industries specifically, have led to a greater research effort aimed at improving understanding of the role of fungi in various fields. Fungi play a key role in soil ecosystems as the primary agent of decomposition, recycling of organic nutrients. Fungi also include important pathogens of plants, insects, bacteria, domestic animals and humans, thus highlighting their importance in many contexts. Temperature directly affects fungal growth and protein dynamics, which ultimately will cascade through to affect crop performance. To study changes in the global protein complement of fungi, proteomic approaches have been used to examine links between temperature stress and fungal proteomic profiles.

    SURVEY METHODOLOGY AND OBJECTIVES: A traditional rather than a systematic review approach was taken to focus on fungal responses to temperature stress elucidated using proteomic approaches. The effects of temperature stress on fungal metabolic pathways and, in particular, heat shock proteins (HSPs) are discussed. The objective of this review is to provide an overview of the effects of temperature stress on fungal proteomes.

    CONCLUDING REMARKS: Elucidating fungal proteomic response under temperature stress is useful in the context of increasing understanding of fungal sensitivity and resilience to the challenges posed by contemporary climate change processes. Although useful, a more thorough work is needed such as combining data from multiple -omics platforms in order to develop deeper understanding of the factor influencing and controlling cell physiology. This information can be beneficial to identify potential biomarkers for monitoring environmental changes in soil, including the agricultural ecosystems vital to human society and economy.

  13. Poverty related diseases amongst Malaysia's low-income community: a review
    Abu Bakar N, Sahimin N, Lim YAL, Ibrahim K, Mohd Zain SN
    Trop Biomed, 2023 Mar 01;40(1):65-75.
    PMID: 37356005 DOI: 10.47665/tb.40.1.013
    Poverty, as proven by several studies, is a driving force behind poor health and hygiene practices. This review attempts to outline common communicable and non-communicable diseases that disproportionately affect Malaysia's 2.91 million low-income households. The current study also looks into the government's housing and healthcare programmes for this demographic to improve their health and well-being. The initial examination yielded incredibly little research on this marginalised community, with event reporting typically generalised to the Malaysian community as a whole rather than analysing disease incidences based on household income, which would better reflect povertydriven diseases. As a result, there is an acute need for more accurate information on the epidemiology of diseases among the poor in order to address this public health issue and provide conclusions that can drive policy designs.
  14. Fulltext Embryonic mercury exposure in zebrafish: Alteration of metabolites and gene expression, related to visual and behavioral impairments
    Abu Bakar N, Wan Ibrahim WN, Zulkiflli AR, Saleh Hodin NA, Kim TY, Ling YS, et al.
    Ecotoxicol Environ Saf, 2023 May;256:114862.
    PMID: 37004432 DOI: 10.1016/j.ecoenv.2023.114862
    The widespread presence of mercury, a heavy metal found in the environment and used in numerous industries and domestic, raises concerns about its potential impact on human health. Nevertheless, the adverse effects of this environmental toxicant at low concentrations are often underestimated. There are emerging studies showing that accumulation of mercury in the eye may contribute to visual impairment and a comorbidity between autism spectrum disorders (ASD) trait and visual impairment. However, the underlying mechanism of visual impairment in humans and rodents is challenging. In response to this issue, zebrafish larvae with a cone-dominated retinal visual system were exposed to 100 nM mercury chloride (HgCl2), according to our previous study, followed by light-dark stimulation, a social assay, and color preference to examine the functionality of the visual system in relation to ASD-like behavior. Exposure of embryos to HgCl2 from gastrulation to hatching increased locomotor activity in the dark, reduced shoaling and exploratory behavior, and impaired color preference. Defects in microridges as the first barrier may serve as primary tools for HgCl2 toxicity affecting vision. Depletion of polyunsaturated fatty acids (PUFAs), linoleic acid, arachidonic acid (ARA), alpha-linoleic acid, docosahexaenoic acid (DHA), stearic acid, L-phenylalanine, isoleucine, L-lysine, and N-acetylputrescine, along with the increase of gamma-aminobutyric acid (GABA), sphingosine-1-phosphate, and citrulline assayed by liquid chromatography-mass spectrometry (LC-MS) suggest that these metabolites serve as biomarkers of retinal impairments that affect vision and behavior. Although suppression of adsl, shank3a, tsc1b, and nrxn1a gene expression was observed, among these tsc1b showed more positive correlation with ASD. Collectively, these results contribute new insights into the possible mechanism of mercury toxicity give rise to visual, cognitive, and social deficits in zebrafish.
  15. Geographical Diversity of Proteomic Responses to Cold Stress in the Fungal Genus Pseudogymnoascus
    Abu Bakar N, Lau BYC, González-Aravena M, Smykla J, Krzewicka B, Karsani SA, et al.
    Microb Ecol, 2023 Dec 07;87(1):11.
    PMID: 38060022 DOI: 10.1007/s00248-023-02311-w
    In understanding stress response mechanisms in fungi, cold stress has received less attention than heat stress. However, cold stress has shown its importance in various research fields. The following study examined the cold stress response of six Pseudogymnoascus spp. isolated from various biogeographical regions through a proteomic approach. In total, 2541 proteins were identified with high confidence. Gene Ontology enrichment analysis showed diversity in the cold stress response pathways for all six Pseudogymnoascus spp. isolates, with metabolic and translation-related processes being prominent in most isolates. 25.6% of the proteins with an increase in relative abundance were increased by more than 3.0-fold. There was no link between the geographical origin of the isolates and the cold stress response of Pseudogymnoascus spp. However, one Antarctic isolate, sp3, showed a distinctive cold stress response profile involving increased flavin/riboflavin biosynthesis and methane metabolism. This Antarctic isolate (sp3) was also the only one that showed decreased phospholipid metabolism in cold stress conditions. This work will improve our understanding of the mechanisms of cold stress response and adaptation in psychrotolerant soil microfungi, with specific attention to the fungal genus Pseudogymnoascus.
  16. Understanding the ideal wound healing mechanistic behavior using in silico modelling perspectives: A review
    Abu Bakar N, Mydin RBSMN, Yusop N, Matmin J, Ghazalli NF
    J Tissue Viability, 2024 Feb;33(1):104-115.
    PMID: 38092620 DOI: 10.1016/j.jtv.2023.11.001
    Complexity of the entire body precludes an accurate assessment of the specific contributions of tissues or cells during the healing process, which might be expensive and time consuming. Because of this, controlling the wound's size, depth, and dimensions may be challenging, and there is not yet an efficient and reliable chronic wound model representation. Furthermore, given the inherent challenges associated with conducting non-invasive in vivo investigations, it becomes peremptory to explore alternative methodologies for studying wound healing. In this context, biologically-realistic mathematical and computational models emerge as a valuable framework that can effectively address this need. Therefore, it might improve our approach to understanding the process at its core. This article will examines all facets of wound healing, including the kinds, pathways, and most current developments in wound treatment worldwide, particularly in silico modelling utilizing both mathematical and structure-based modelling techniques. It may be helpful to identify the crucial traits through the feedback loop of computer models and experimental investigations in order to build innovative therapies to cure wounds. Hence the effectiveness of personalised medicine and more targeted therapy in the healing of wounds may be enhanced by this interdisciplinary expertise.
  17. Proteomic characterization of Pseudogymnoascus spp. isolates from polar and temperate regions
    Abu Bakar N, Chung BLY, Smykla J, Karsani SA, Alias SA
    Mycologia, 2024;116(3):449-463.
    PMID: 38484286 DOI: 10.1080/00275514.2024.2313429
    Proteomics has been used extensively in the field of mycology, mainly in trying to understand the complex network of protein-protein interactions that has been implicated in the molecular functions of fungi. It is also a useful tool to compare metabolic differences within a genus. Species of Pseudogymnoascus, a genus under the phyla Ascomycota, have been shown to play an important role in the soil environment. They have been found in both polar and temperate regions and are a known producer of many extracellular hydrolases that contribute to soil decomposition. Despite the apparent importance of Pseudogymnoascus spp. in the soil ecosystem, investigations into their molecular functions are still very limited. In the present study, proteomic characterization of six Pseudogymnoascus spp. isolated from three biogeographic regions (the Arctic, Antarctic, and temperate regions) was carried out using tandem mass spectrometry. Prior to proteomic analysis, the optimization for protein extraction was carried out. Trichloroacetic acid‑acetone‑phenol was found to be the best extraction method to be used for proteomic profiling of Pseudogymnoascus spp. The proteomic analysis identified 2003 proteins that were successfully mapped to the UniProtKB database. The identified proteins were clustered according to their biological processes and molecular functions. The shared proteins found in all Pseudogymnoascus spp. (1201 proteins) showed a significantly close relationship in their basic cellular functions, despite differences in morphological structures. Analysis of Pseudogymnoascus spp. proteome also identified proteins that were unique to each region. However, a high number of these proteins belonged to protein families of similar molecular functions, namely, transferases and hydrolases. Our proteomic data can be used as a reference for Pseudogymnoascus spp. across different global regions and a foundation for future soil ecosystem function research.
  18. Fulltext Gastroprotective Effect of Polypeptide-K Isolated from Momordica charantia's Seeds on Multiple Experimental Gastric Ulcer Models in Rats
    Abu Bakar N', Hakim Abdullah MN, Lim V, Yong YK
    Evid Based Complement Alternat Med, 2022;2022:6098929.
    PMID: 35069762 DOI: 10.1155/2022/6098929
    Peptic ulcer disease is a multifactorial disorder and is the most significant public health concern nowadays. Previous study showed that essential oil extracted from Momordica charantia's seed exhibited gastroprotective effect. However, the evidence for the gastroprotective effect of its active compound, polypeptide K (PPK), remains unclear. This study aimed to examine the preventive effect of PPK against different experimental gastric lesions models in rats. The possible gastroprotective effect of PPK was assessed in hydrochloride ethanol- and indomethacin-induced gastric ulcer models in Sprague Dawley rats and was further evaluated macroscopically and microscopically. Pyloric ligation experiments were used to investigate gastric secretion. Oral administration of PPK at all concentrations (10, 25, and 50 mg/kg) showed significant (p < 0.05) reduction in total area of lesion in both hydrochloride ethanol- and indomethacin-induced gastric ulcer models. The highest inhibition rate was seen in PPK dose of 50 mg/kg with 64.9% and 72.2% on hydrochloride ethanol and indomethacin models, respectively. Microscopically, PPK preserved the normal architectures of the gastric tissues from being damaged by hydrochloride ethanol and indomethacin. Further, in the pyloric ligation studies, PPK significantly (p < 0.05) decreased the ulcer area where the highest protection was exhibited by 50 mg/kg with 70% inhibition rate. Moreover, all concentrations of PPK also significantly (p < 0.05) enhanced the gastric wall mucus secretion. Collectively, this study demonstrated the gastroprotective effect of PPK on hydrochloride ethanol- and indomethacin-induced gastric ulcer models. The possible mechanism might be associated with enhanced mucus secretion and thus lowering the total acidity.
  19. Fulltext Essential Oils Derived from Momordica charantia Seeds Exhibited Antiulcer Activity against Hydrogen Chloride/Ethanol and Indomethacin
    Abu Bakar N', Hakim Abdullah MN, Lim V, Yong YK
    Evid Based Complement Alternat Med, 2021;2021:5525584.
    PMID: 33976701 DOI: 10.1155/2021/5525584
    Momordica charantia (MC) is popular for its medicinal uses especially for treating diabetic-related complications. However, the antiulcer activity of essential oil derived from the seeds has not been systematically studied. This study aims to evaluate the gastroprotective activities of essential oil derived from the seed of MC induced by hydrochloride acid/ethanol (HCl/EtOH) and indomethacin and pylorus-ligation model. Gastric ulceration was induced by oral administration of HCl/EtOH solution or indomethacin on day 7 after animals have been pretreated with testing compounds. The first group received just distilled water and the second group received ranitidine (100 mg/kg). Groups 3, 4, and 5 received 10, 50, and 100 mg/kg of essential oil based on their body weight (10 mL/kg), respectively. Macroscopically, pretreatment of essential oil extracted from MC significantly decreased ulceration induced by HCl/EtOH and indomethacin in vivo. Microscopically, essential oil also significantly suppressed the formation of edema, epithelial disruption, and mucosa erosions. Moreover, essential oil significantly elevated the pH without decreasing the total acidity of the gastric juice and was able to increase the amount of adherent mucus compared to control. Current results provide scientific basis to the ethno-pharmacological usage of the MC in preventing ulcer formation induced by HCl/EtOH and indomethacin.
  20. The effect of oleic acid stabilizer on the surface properties of bimetallic PtNi catalysts
    Abu Bakar NH, Abu Bakar M, Bettahar MM, Ismail J, Monteverdi S
    J Nanosci Nanotechnol, 2013 Jul;13(7):5034-43.
    PMID: 23901527
    A detailed study on the surface properties of oleic acid-stabilized PtNi nanoparticles supported on silica is reported. The oleic acid-stabilized PtNi nanoparticles were synthesized using NaBH4 as the reducing agent at various temperatures and oleic acid concentrations, prior to incorporation onto the silica support. X-ray diffraction studies of the unsupported oleic acid-stabilized PtNi particles revealed that the PtNi existed as alloys. Upon incorporation onto silica support, surface properties of the catalysts were investigated using H2-temperature reduction (H2-TPR), H2-temperature desorption (H2-TPD) and H2-chemisorption techniques. It was found that for the bimetallic catalysts, no oxides or very little oxidation occurred. Furthermore, these catalysts exhibited both Pt and Ni active sites on its surface though the availability of Ni active sites was dominant. A comparison of the surface properties of these materials with those prepared without oleic acid in our previous work [N. H. H. Abu Bakar et al., J. Catal. 265, 63 (2009)] and how they affect the hydrogenation of benzene is also discussed.
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