Browse publications by year: 2023

  1. Rasidi WNA, Seluakumaran K, Jamaluddin SA
    Eur Arch Otorhinolaryngol, 2023 Oct;280(10):4391-4400.
    PMID: 36988687 DOI: 10.1007/s00405-023-07929-7
    PURPOSE: Pure-tone audiometry (PTA) is the gold standard for screening and diagnosis of hearing loss but is not always accessible. This study evaluated a simplified cochlear frequency selectivity (FS) measure as an alternative option to screen for early frequency-specific sensorineural hearing loss (SNHL).

    METHODS: FS measures at 1 and 4 kHz center frequencies were obtained using a custom-made software in normal-hearing (NH), slight SNHL and mild-to-moderate SNHL subjects. For comparison, subjects were also assessed with the Malay Digit Triplet Test (DTT) and the shortened Malay Speech, Spatial and Qualities of Hearing Scale (SSQ) questionnaire.

    RESULTS: Compared to DTT and SSQ, the FS measure at 4 kHz was able to distinguish NH from slight and mild-to-moderate SNHL subjects, and was strongly correlated with their thresholds in quiet determined separately in 1-dB step sizes at the similar test frequency. Further analysis with receiver operating characteristic (ROC) curves indicated area under the curve (AUC) of 0.77 and 0.83 for the FS measure at 4 kHz when PTA thresholds of NH subjects were taken as ≤ 15 dB HL and ≤ 20 dB HL, respectively. At the optimal FS cut-off point for 4 kHz, the FS measure had 77.8% sensitivity and 86.7% specificity to detect 20 dB HL hearing loss.

    CONCLUSION: FS measure was superior to DTT and SSQ questionnaire in detecting early frequency-specific threshold shifts in SNHL subjects, particularly at 4 kHz. This method could be used for screening subjects at risk of noise-induced hearing loss.

    MeSH terms: Audiometry, Pure-Tone/methods; Auditory Threshold; Hearing; Humans; Surveys and Questionnaires; Speech
  2. Yeo JS, Koting S, Onn CC, Radwan MKH, Cheah CB, Mo KH
    PMID: 36988805 DOI: 10.1007/s11356-023-26496-2
    This research incorporates sustainable materials such as ground granulated blast furnace slag (GGBS) and recycled waste glass (RWG) as cement and fine aggregate replacement respectively to produce green dry mix mortar paving blocks. The GGBS and RWG contents in the mortar paving block were optimised using the response surface methodology (RSM), considering the performances of the ultrasonic pulse velocity (UPV), flexural and compressive strengths, water absorption, and Cantabro loss. Life cycle assessment (LCA) was also conducted to evaluate the environmental impact of the optimised green mortar paving blocks. The RSM suggested that the paving block with optimum GGBS and RWG contents of 26.5% and 91.3%, respectively, could exhibit compressive strength of 36.5 MPa, which complied with the requirement for concrete segmental paving units (MA20). Excluding the mixes not fulfilling the MA20 requirement, the mix with 40% GGBS and 100% RWG exhibited the lowest values for the acidification potential (AP), global warming potential (GWP), photochemical oxidation (POCP), abiotic depletion potential for fossil fuel (ADPF), and water scarcity/strength ratio. Whereas, for eutrophication potential (EP) and abiotic depletion for elements (ADP (elements))/strength ratio, the mix with 100% RWG exhibited the lowest value. The optimised mix from RSM showed a similar performance as the two mixes.
  3. Khalik WF, Ho LN, Ong SA, Lai NB, Thor SH, Yap KL
    PMID: 36988807 DOI: 10.1007/s11356-023-26589-y
    Cathode in photocatalytic fuel cell (PFC) plays a crucial role in degradation of organic contaminants. In this study, synthesized copper oxide (CuO) was loaded on carbon plate and used as photocathode in PFC for degradation of synthetic azo dye Reactive Black 5 (RB5) and real textile wastewater. Morphology and structural phase of the synthesized CuO were analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. Several operating parameters had been investigated such as light irradiation, initial dye concentration, and pH of azo dye solution within 6 h of irradiation time. The lowest initial concentration of RB5 (10 mg L-1) achieved 100% color removal compared to the highest initial concentration (40 mg L-1) which only achieved 77.1% color removal within 6 h of irradiation time. The influence of external resistance was significant in electricity generation but trivial in dye degradation efficiency. The external resistance of 6000 Ω yielded highest maximum power density, with Pmax of 0.2631 μW cm-2, followed by 1000 Ω (0.2196 μW cm-2) and 8000 Ω (0.1587 μW cm-2), respectively. The real textile wastewater with dilution ratio (DR) 1:6 yielded the highest energy conversion efficiency, η (3.62%), followed by DR 1:4 (3.19%) and DR 1:2 (1.96%), respectively.
  4. Chuah YY, Guo MM, Lee YY
    Br J Hosp Med (Lond), 2023 Mar 02;29(3):1.
    PMID: 36989145 DOI: 10.12968/hmed.2022.0237
    MeSH terms: Diagnosis, Differential; Humans; Abdominal Pain/diagnosis; Abdominal Pain/etiology
  5. Rajamanikam A, Isa MNM, Samudi C, Devaraj S, Govind SK
    PLoS Negl Trop Dis, 2023 Mar;17(3):e0011170.
    PMID: 36989208 DOI: 10.1371/journal.pntd.0011170
    Whilst the influence of intestinal microbiota has been shown in many diseases such as irritable bowel syndrome, colorectal cancer, and aging, investigations are still scarce on its role in altering the nature of other infective organisms. Here we studied the association and interaction of Blastocystis sp. and human intestinal microbiota. In this study, we investigated the gut microbiome of Blastocystis sp.-free and Blastocystis sp. ST3-infected individuals who are symptomatic and asymptomatic. We tested if the expression of phenotype and pathogenic characteristics of Blastocystis sp. ST3 was influenced by the alteration of its accompanying microbiota. Blastocystis sp. ST3 infection alters bacterial composition. Its presence in asymptomatic individuals showed a significant effect on microbial richness compared to symptomatic ones. Inferred metagenomic findings suggest that colonization of Blastocystis sp. ST3 could contribute to the alteration of microbial functions. For the first time, we demonstrate the influence of bacteria on Blastocystis sp. pathogenicity. When Blastocystis sp. isolated from a symptomatic individual was co-cultured with bacterial suspension of Blastocystis sp. from an asymptomatic individual, the parasite demonstrated increased growth and reduced potential pathogenic expressions. This study also reveals that Blastocystis sp. infection could influence microbial functions without much effect on the microbiota diversity itself. Our results also demonstrate evidence on the influential role of gut microbiota in altering the characteristics of the parasite, which becomes the basis for the contradictory findings on the parasite's pathogenic role seen across different studies. Our study provides evidence that asymptomatic Blastocystis sp. in a human gut can be triggered to show pathogenic characteristics when influenced by the intestinal microbiota.
    MeSH terms: Bacteria; Feces/parasitology; Humans; Phenotype; Virulence
  6. Brown C, Boyd DS, Sjögersten S, Vane CH
    PLoS One, 2023;18(3):e0280187.
    PMID: 36989287 DOI: 10.1371/journal.pone.0280187
    Tropical peatlands are important carbon stores that are vulnerable to drainage and conversion to agriculture. Protection and restoration of peatlands are increasingly recognised as key nature based solutions that can be implemented as part of climate change mitigation. Identification of peatland areas that are important for protection and restauration with regards to the state of their carbon stocks, are therefore vital for policy makers. In this paper we combined organic geochemical analysis by Rock-Eval (6) pyrolysis of peat collected from sites with different land management history and optical remote sensing products to assess if remotely sensed data could be used to predict peat conditions and carbon storage. The study used the North Selangor Peat Swamp forest, Malaysia, as the model system. Across the sampling sites the carbon stocks in the below ground peat was ca 12 times higher than the forest (median carbon stock held in ground vegetation 114.70 Mg ha-1 and peat soil 1401.51 Mg ha-1). Peat core sub-samples and litter collected from Fire Affected, Disturbed Forest, and Managed Recovery locations (i.e. disturbed sites) had different decomposition profiles than Central Forest sites. The Rock-Eval pyrolysis of the upper peat profiles showed that surface peat layers at Fire Affected, Disturbed Forest, and Managed Recovery locations had lower immature organic matter index (I-index) values (average I-index range in upper section 0.15 to -0.06) and higher refractory organic matter index (R -index) (average R-index range in upper section 0.51 to 0.65) compared to Central Forest sites indicating enhanced decomposition of the surface peat. In the top 50 cm section of the peat profile, carbon stocks were negatively related to the normalised burns ratio (NBR) (a satellite derived parameter) (Spearman's rho = -0.664, S = 366, p-value = <0.05) while there was a positive relationship between the hydrogen index and the normalised burns ratio profile (Spearman's rho = 0.7, S = 66, p-value = <0.05) suggesting that this remotely sensed product is able to detect degradation of peat in the upper peat profile. We conclude that the NBR can be used to identify degraded peatland areas and to support identification of areas for conversation and restoration.
    MeSH terms: Carbon/analysis; Soil/chemistry; Wetlands; Remote Sensing Technology*; Forests*
  7. Panickar R, Aziz Z, Mohd Sani N, Kamarulzaman A
    Patient Educ Couns, 2023 Jul;112:107707.
    PMID: 36989861 DOI: 10.1016/j.pec.2023.107707
    OBJECTIVES: To identify technologies used in vaccine safety communication and evaluate their impact on vaccination intention, uptake, knowledge, attitude, and perceptions of consumers.

    METHODS: We searched 6 electronic databases to identify randomised controlled trials assessing the impact of using technology in vaccine safety communication. The Cochrane Collaboration's tool for assessing risk of bias was used to evaluate each study.

    RESULTS: We included 22 studies involving 27,109 participants from 8 countries; 15 studies assessed the use of videos and 7 examined innovative technologies. Using videos significantly improved knowledge (n = 3) and participant engagement (n = 2) compared to printed material. Among the innovative technologies, the use of virtual reality, and smartphone applications incorporating social networking or gamification significantly increased vaccination knowledge, confidence, and engagement. The studies showed that narrative messaging increased perceived disease severity (n = 2) and vaccination intention (n = 2).

    CONCLUSIONS: While the use of innovative technologies is increasing, videos currently remain the most popular technology for vaccine safety communication. Communication technology, particularly with narrative messaging, improves patient engagement and comprehension.

    PRACTICE IMPLICATIONS: Health authorities should increase focus on using videos and smartphone applications for vaccine safety communication. Collaboration among stakeholders is essential to develop guidelines on effective message content to complement the technology.

    MeSH terms: Communication; Humans; Vaccination/adverse effects; Narration; Mobile Applications*
  8. Redican E, Vang ML, Shevlin M, Ghazali S, Elklit A
    Acta Psychol (Amst), 2023 May;235:103896.
    PMID: 36990035 DOI: 10.1016/j.actpsy.2023.103896
    BACKGROUND: Although it is well-established that people can experience multiple traumatic events, there are few studies examining the co-occurrence of such experiences in non-Western nations. The current study sought to examine the occurrence of multiple potentially traumatic experiences (PTEs) and their associations with posttraumatic stress disorder (PTSD) among adolescents from two Asian nations.

    METHODS: Latent class analysis (LCA) was employed to model the co-occurrence of PTEs in two school samples of adolescents from India (n = 411) and Malaysia (n = 469). Demographic correlates (i.e., sex, age, household composition, parent education) of the latent classes and the association between latent class membership and probable diagnosis of posttraumatic stress disorder (PTSD) were examined.

    RESULTS: The LCA identified three latent classes for the Indian sample: 'Low Risk - moderate sexual trauma', 'Moderate Risk', and 'High Risk'. Similarly, three classes were also identified for the Malaysian sample: 'Low Risk', 'Moderate Risk', and 'High Risk'. Membership of 'Moderate Risk' was associated with male sex in both samples, and with older age and lower levels of parental education attainment in the Malaysian sample. No correlates of 'High Risk' class were identified in either sample. Membership of the 'High Risk' class was significantly associated with probable PTSD diagnosis in both samples, while membership of the 'Moderate Risk' class was associated with probable PTSD diagnosis in the Malaysian sample.

    CONCLUSION: Findings from this study correspond with Western studies indicating co-occurrence of PTEs to be common and to represent a salient risk factor for the development of PTSD.

    MeSH terms: Adolescent; Humans; India/epidemiology; Malaysia/epidemiology; Male; Risk Factors; Schools
  9. Woon JM, Khoo KS, Al-Zahrani AA, Alanazi MM, Lim JW, Cheng CK, et al.
    Environ Res, 2023 Mar 28;227:115780.
    PMID: 36990197 DOI: 10.1016/j.envres.2023.115780
    Hydrogen is a clean and green biofuel choice for the future because it is carbon-free, non-toxic, and has high energy conversion efficiency. In exploiting hydrogen as the main energy, guidelines for implementing the hydrogen economy and roadmaps for the developments of hydrogen technology have been released by several countries. Besides, this review also unveils various hydrogen storage methods and applications of hydrogen in transportation industry. Biohydrogen productions from microbes, namely, fermentative bacteria, photosynthetic bacteria, cyanobacteria, and green microalgae, via biological metabolisms have received significant interests off late due to its sustainability and environmentally friendly potentials. Accordingly, the review is as well outlining the biohydrogen production processes by various microbes. Furthermore, several factors such as light intensity, pH, temperature and addition of supplementary nutrients to enhance the microbial biohydrogen production are highlighted at their respective optimum conditions. Despite the advantages, the amounts of biohydrogen being produced by microbes are still insufficient to be a competitive energy source in the market. In addition, several major obstacles have also directly hampered the commercialization effors of biohydrogen. Thus, this review uncovers the constraints of biohydrogen production from microbes such as microalgae and offers solutions associated with recent strategies to overcome the setbacks via genetic engineering, pretreatments of biomass, and introduction of nanoparticles as well as oxygen scavengers. The opportunities of exploiting microalgae as a suastainable source of biohydrogen production and the plausibility to produce biohydrogen from biowastes are accentuated. Lastly, this review addresses the future perspectives of biological methods to ensure the sustainability and economy viability of biohydrogen production.
  10. Takao N, Furuta M, Takeshita T, Kageyama S, Goto T, Zakaria MN, et al.
    J Oral Sci, 2023;65(2):107-110.
    PMID: 36990753 DOI: 10.2334/josnusd.22-0388
    PURPOSE: Second-hand smoke has adverse effects on oral health. This cohort study used a multilevel approach to investigate the association of second-hand smoke exposure, as determined by salivary cotinine level, with dental caries in adolescents.

    METHODS: Data from 75 adolescents aged 11 or 12 years and 2,061 teeth without dental caries were analyzed in this study. Annual dental examinations to assess dental caries were conducted between 2018 and 2021. Salivary cotinine and Dentocult SM-Strip level were measured at baseline. Information on the smoking habits of parents, snack frequency, regular dental visits, and use of fluoride toothpaste was collected at baseline from parent-reported questionnaires.

    RESULTS: During the 3-year follow-up, dental caries was noted in 21 adolescents and 43 teeth. Participants exposed to parental smoking had higher salivary cotinine levels than those whose parents did not smoke. The multilevel Cox regression model showed that a high salivary cotinine level was associated with the incidence of dental caries, after adjusting for potential confounding factors (hazard ratio, 3.39; 95% confidence interval 1.08-10.69).

    CONCLUSION: This study suggests that the risk of dental caries is higher for adolescents who have high salivary cotinine levels attributable to second-hand smoke exposure.

    MeSH terms: Adolescent; Cotinine/analysis; Humans; Surveys and Questionnaires; Cohort Studies
  11. Cooper DM, Bojke C, Ghosh P
    J Tissue Viability, 2023 Mar 16.
    PMID: 36990897 DOI: 10.1016/j.jtv.2023.03.001
    BACKGROUND: Wounds cost £8.3 billion per year in the United Kingdom (UK) annually. Venous leg ulcers (VLUs) account for 15% of wounds and can be complicated to heal, increasing nurse visits and resource costs. Recent wound bed preparation consensus recommends wound cleansing and biofilm disrupting agents. However, inert cleansers such as tap water or saline are inexpensive, an evaluation of evidence is required to justify the higher upfront costs of treatment with active cleansers. We undertook a cost-effectiveness analysis of the use of a biofilm disrupting and cleansing solution and gel, Prontosan® Solution and Gel X, (PSGX) (B Braun Medical), as compared to the standard practice of using saline solution, for treating VLUs.

    METHODS: A Markov model was parameterised to one-year costs and health-related quality of life consequences of treating chronic VLUs with PSGX versus saline solution. Costs are viewed from a UK healthcare payer perspective, include routine care and management of complications. A systematic literature search was performed to inform the clinical parameters of the economic model. Deterministic univariate sensitivity analysis (DSA) and probabilistic sensitivity analysis (PSA) were undertaken.

    RESULTS: For PSGX an Incremental Net Monetary Benefit (INMB) of £1,129.65 to £1,042.39 per patient (with a Maximum Willingness to Pay of £30k and £20k per QALY respectively), of which cost savings are £867.87 and 0.0087 quality-adjusted life years (QALYs) gain per patient. PSA indicates a 99.3% probability of PSGX being cost-effective over saline.

    CONCLUSIONS: PSGX for the treatment of VLUs is dominant compared with saline solution in the UK with expected cost-savings within a year and improved patient outcomes.

  12. Ng WC, Lokanathan Y, Fauzi MB, Baki MM, Zainuddin AA, Phang SJ, et al.
    Sci Rep, 2023 Mar 29;13(1):5128.
    PMID: 36991038 DOI: 10.1038/s41598-023-32080-y
    Glottic insufficiency is one of the voice disorders affecting all demographics. Due to the incomplete closure of the vocal fold, there is a risk of aspiration and ineffective phonation. Current treatments for glottic insufficiency include nerve repair, reinnervation, implantation and injection laryngoplasty. Injection laryngoplasty is favored among these techniques due to its cost-effectiveness and efficiency. However, research into developing an effective injectable for the treatment of glottic insufficiency is currently lacking. Therefore, this study aims to develop an injectable gelatin (G) hydrogel crosslinked with either 1-ethyl-3-(3-dimethylaminpropyl)carbodiimide hydrochloride) (EDC) or genipin (gn). The gelation time, biodegradability and swelling ratio of hydrogels with varying concentrations of gelatin (6-10% G) and genipin (0.1-0.5% gn) were investigated. Some selected formulations were proceeded with rheology, pore size, chemical analysis and in vitro cellular activity of Wharton's Jelly Mesenchymal Stem Cells (WJMSCs), to determine the safety application of the selected hydrogels, for future cell delivery prospect. 6G 0.4gn and 8G 0.4gn were the only hydrogel groups capable of achieving complete gelation within 20 min, exhibiting an elastic modulus between 2 and 10 kPa and a pore size between 100 and 400 μm. Moreover, these hydrogels were biodegradable and biocompatible with WJMSCs, as > 70% viability were observed after 7 days of in vitro culture. Our results suggested 6G 0.4gn and 8G 0.4gn hydrogels as potential cell encapsulation injectates. In light of these findings, future research should focus on characterizing their encapsulation efficiency and exploring the possibility of using these hydrogels as a drug delivery system for vocal fold treatment.
    MeSH terms: Vocal Cords; Iridoids/chemistry
  13. Shaffi SC, Zakaria N, Halim NSSA, Ishtiah AA, Patar AA, Yahaya BH
    Adv Exp Med Biol, 2023 Mar 30.
    PMID: 36991294 DOI: 10.1007/5584_2023_767
    INTRODUCTION: The lung is a complex organ composed of numerous cell types. Exposure to air pollutants, cigarette smoke, bacteria, viruses, and many others may cause injury to the epithelial cells that line the conducting airways and alveoli. Organoids are the 3D self-organising structures grown from stem cells and generated from adult stem and progenitor cells. Lung organoids are fascinating tools to investigate human lung development in vitro. The objective of this study was to establish a rapid method for generating lung organoids with a direct culture strategy.

    METHODS: Trachea and lung organoids were derived from mixed cell populations of mice primary airway epithelial cells, fibroblasts, and lung microvascular endothelial cells and directly digested from the whole cell population in the distal lung.

    RESULTS: The formation of spheres appeared as early as 3 days and continued to proliferate until day 5. The generation of trachea and lung organoids self-organised into discrete epithelial structures was formed within less than 10 days.

    CONCLUSION: We conclude that researchers will be able to examine cellular involvement during organ formation and molecular networks because organoids come in a variety of morphologies and stages of development, and this organoid protocol may be used for modelling lung diseases as a platform for therapeutic purposes and suitable for personalised medicine for respiratory diseases.

  14. Al-Jumaili AHA, Muniyandi RC, Hasan MK, Paw JKS, Singh MJ
    Sensors (Basel), 2023 Mar 08;23(6).
    PMID: 36991663 DOI: 10.3390/s23062952
    Traditional parallel computing for power management systems has prime challenges such as execution time, computational complexity, and efficiency like process time and delays in power system condition monitoring, particularly consumer power consumption, weather data, and power generation for detecting and predicting data mining in the centralized parallel processing and diagnosis. Due to these constraints, data management has become a critical research consideration and bottleneck. To cope with these constraints, cloud computing-based methodologies have been introduced for managing data efficiently in power management systems. This paper reviews the concept of cloud computing architecture that can meet the multi-level real-time requirements to improve monitoring and performance which is designed for different application scenarios for power system monitoring. Then, cloud computing solutions are discussed under the background of big data, and emerging parallel programming models such as Hadoop, Spark, and Storm are briefly described to analyze the advancement, constraints, and innovations. The key performance metrics of cloud computing applications such as core data sampling, modeling, and analyzing the competitiveness of big data was modeled by applying related hypotheses. Finally, it introduces a new design concept with cloud computing and eventually some recommendations focusing on cloud computing infrastructure, and methods for managing real-time big data in the power management system that solve the data mining challenges.
  15. Saeed K, Khalil W, Al-Shamayleh AS, Ahmad I, Akhunzada A, ALharethi SZ, et al.
    Sensors (Basel), 2023 Mar 11;23(6).
    PMID: 36991755 DOI: 10.3390/s23063044
    The exponentially growing concern of cyber-attacks on extremely dense underwater sensor networks (UWSNs) and the evolution of UWSNs digital threat landscape has brought novel research challenges and issues. Primarily, varied protocol evaluation under advanced persistent threats is now becoming indispensable yet very challenging. This research implements an active attack in the Adaptive Mobility of Courier Nodes in Threshold-optimized Depth-based Routing (AMCTD) protocol. A variety of attacker nodes were employed in diverse scenarios to thoroughly assess the performance of AMCTD protocol. The protocol was exhaustively evaluated both with and without active attacks with benchmark evaluation metrics such as end-to-end delay, throughput, transmission loss, number of active nodes and energy tax. The preliminary research findings show that active attack drastically lowers the AMCTD protocol's performance (i.e., active attack reduces the number of active nodes by up to 10%, reduces throughput by up to 6%, increases transmission loss by 7%, raises energy tax by 25%, and increases end-to-end delay by 20%).
  16. Raju T, Manchanayake T, Danial A, Zamri-Saad M, Azmai MNA, Md Yasin IS, et al.
    Vaccines (Basel), 2023 Mar 06;11(3).
    PMID: 36992186 DOI: 10.3390/vaccines11030602
    This study describes the levels of gut lysozyme and IgM, the number, size and density of gut-associated lymphoid tissue (GALT) regions, and the lymphocyte population in Asian seabass following field oral administration of a feed-based vaccine. Fish in a grow-out farm were selected and divided into two groups; Group 1 was vaccinated at week 0, 2, and 6, while Group 2 was not vaccinated. Samplings were done at 2-week intervals when the fish were observed for clinical signs, and gross lesions were recorded. The intestinal tissue and gut lavage fluid were collected. GALT regions (numbers, size, density and population of lymphocytes) were analyzed. Clinical signs such as abnormal swimming pattern and death, and gross lesions including scale loss, ocular opacity, and skin ulceration were observed in both groups. At the end of the study, the incidence rate between both groups were significantly different (p < 0.05). The gut IgM level and lysozyme activity, lymphocyte population, number, size and density of GALT regions of Group 1 were significantly (p < 0.05) higher than Group 2. Therefore, this study concludes that the feed-based vaccine reduces the incidence of vibriosis by stimulating the gut immunity of the vaccinated fish with an enhanced GALT region, specific IgM production against Vibrio harveyi, and lysozyme responses.
  17. Koh JX, Masomian M, Anasir MI, Ong SK, Poh CL
    Vaccines (Basel), 2023 Mar 11;11(3).
    PMID: 36992213 DOI: 10.3390/vaccines11030629
    EV-A71 is a common viral pathogen that causes hand, foot and mouth disease. It is a single-stranded RNA virus that has a low fidelity RNA polymerase and, as a result, spontaneous mutations frequently occur in the EV-A71 genome. The mutations within the genome give rise to quasispecies within the viral population that could be further defined by haplotypes. In vitro virulence of EV-A71 was shown by plaque size in Rhabdomyosarcoma (RD) cells, which was substantiated by in vitro characterizations of growth, RNA replication, binding, attachment and host cell internalization. Viruses could exhibit different host cell adaptations in different cell lines during viral passaging. The EV-A71/WT (derived from EV-A71 subgenotype B4) was shown to comprise six haplotypes through next-generation sequencing, where only EV-A71/Hap2 was found to be cultivable in RD cells, while EV-A71/Hap4 was the only cultivable haplotype in Vero cells. The EV-A71/WT produced plaques of four different sizes (small, medium, big, huge) in RD cells, while only two plaque variants (small, medium) were present in Vero cells. The small plaque variant isolated from RD cells displayed lower RNA replication rates, slower in vitro growth kinetics, higher TCID50 and lower attachment, binding and entry ability when compared against EV-A71/WT due to the mutation at 3D-S228P that disrupted the active site of the RNA polymerase, resulting in low replication and growth of the variant.
  18. Lee KW, Yap SF, Ong HT, Oo M, Swe KMM
    Vaccines (Basel), 2023 Mar 13;11(3).
    PMID: 36992222 DOI: 10.3390/vaccines11030638
    Vaccination is a key public health strategy that is known to be effective in mitigating the risk of infection and severe disease. However, in the context of the COVID-19 pandemic, the percentage (<50%) of Malaysians who have received a booster for the COVID-19 vaccine has remained stagnant over a year. This study aimed to determine the prevalence of and the factors associated with hesitancy toward the second dose of booster for the COVID-19 vaccine. A web-based cross-sectional study was conducted from August to November 2022. The Oxford Vaccine Hesitancy Scale was used to assess the hesitancy toward the second dose of booster for the COVID-19 vaccine. Simple and multiple factors logistic regressions were used to determine the predictors of hesitancy. A p-value less than 0.05 was considered to be statistically significant. Data from 798 respondents were included in the analysis. The prevalence of hesitancy toward the second booster of the COVID-19 vaccine was 26.7%. The predictors of second-booster hesitancy were older age (AOR = 1.040, 95 CI = 1.022, 1.058), having received the third dose (first booster) because of instruction by the government (AOR = 2.125, 95% CI = 1.380, 3.274), concern about serious long term side effects of the vaccine (AOR = 4.010, 95% CI = 2.218, 7.250), and opinions of close friends and immediate family members that the booster is harmful (AOR = 2.201, 95% CI = 1.280, 3.785). Conversely, factors that appear to reduce vaccine booster hesitancy were acceptance of the third dose due to the high number of cases and the increasing rate of infection (AOR = 0.548, 95% CI = 0.317, 0.947), the belief that the vaccine will decrease the risk of getting the infection (AOR = 0.491, 95% CI = 0.277, 0.870), and opinions of close friends and immediate family members that the booster is helpful (AOR = 0.479, 95% CI = 0.273, 0.840). In conclusion, more than one-fifth of Malaysians were hesitant to take the second booster of the COVID-19 vaccine. This suggests that appropriate steps that increase vaccine acceptance, taking into consideration the findings of the present study, are needed to address this issue and to foster more positive attitudes toward vaccination. The survey was available in three main languages but limited to people with internet access; hence, it would likely be biased toward younger adults and social media users and exclude those with limited or no internet access, in particular older people. Therefore, the results are not representative of the Malaysian population at large and caution should be exercised when interpreting the findings.
  19. Lee MF, Wu YS, Poh CL
    Viruses, 2023 Mar 08;15(3).
    PMID: 36992414 DOI: 10.3390/v15030705
    Dengue is a major global health threat causing 390 million dengue infections and 25,000 deaths annually. The lack of efficacy of the licensed Dengvaxia vaccine and the absence of a clinically approved antiviral against dengue virus (DENV) drive the urgent demand for the development of novel anti-DENV therapeutics. Various antiviral agents have been developed and investigated for their anti-DENV activities. This review discusses the mechanisms of action employed by various antiviral agents against DENV. The development of host-directed antivirals targeting host receptors and direct-acting antivirals targeting DENV structural and non-structural proteins are reviewed. In addition, the development of antivirals that target different stages during post-infection such as viral replication, viral maturation, and viral assembly are reviewed. Antiviral agents designed based on these molecular mechanisms of action could lead to the discovery and development of novel anti-DENV therapeutics for the treatment of dengue infections. Evaluations of combinations of antiviral drugs with different mechanisms of action could also lead to the development of synergistic drug combinations for the treatment of dengue at any stage of the infection.
    MeSH terms: Antiviral Agents/pharmacology; Antiviral Agents/therapeutic use; Antiviral Agents/chemistry; Humans; Virus Replication
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