Displaying publications 1 - 20 of 32 in total

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  1. Cheok LH, Tang ASO, Desmond S, Wong YL, Cheong YK, Ng SC, et al.
    IDCases, 2021;26:e01255.
    PMID: 34458097 DOI: 10.1016/j.idcr.2021.e01255
    Central nervous system melioidosis is an uncommon presentation of melioidosis infection. We report a case of a disseminated melioidosis infection with central nervous system, pulmonary, spleen, bone and cutaneous involvement in a patient with underlying systemic lupus erythematous. The diagnosis was confirmed based on positive blood and cerebrospinal fluid cultures coupled with radiological findings. Agriculture contact and underlying immunocompromised state were the predisposing risk factors for melioidosis infection in this case. Our patient was successfully treated with 10 weeks of intensive antibiotics therapy and 1 year of eradication antibiotics therapy with significant clinical and radiological improvement.
  2. Chong NT, Chin VY, Haneline MT, Wong YK
    J Chiropr Med, 2023 Mar;22(1):20-26.
    PMID: 36844990 DOI: 10.1016/j.jcm.2022.05.001
    OBJECTIVE: The purpose of this study was to identify and compare the ergonomic risk factors of year 4 and year 5 dental students attending International Medical University.

    METHODS: This was an exploratory, observational study evaluating ergonomic risk factors among year 4 and year 5 dental students, with a total of 89 participants. The students' ergonomic risk components were evaluated using the Rapid Upper Limb Assessment (RULA) worksheet. Descriptive statistics were used to analyze the RULA scores, and the Mann-Whitney U test served to determine the difference of ergonomic risk between year 4 and year 5 dental students.

    RESULTS: The descriptive analysis showed that the participants' (N = 89) median final RULA score was 6.00 (standard deviation = 0.716). One-year difference in the years of clinical practice did not produce a significant difference in the final RULA score (U = 913.0, P = 0.49). The final RULA scores showed year 4 dental students had a higher mean ranking (year 4 = 46.65, year 5 = 43.23). Furthermore, the Mann-Whitney U test indicated that this was not statistically significant (U = 913.0, P = 0.49).

    CONCLUSION: The descriptive analysis showed that the final RULA score of the participants indicated that the participants were in a high-risk category for experiencing work-related musculoskeletal disorders due to poor ergonomics. Contributing physical factors included working in asymmetric, awkward, and static positions in a confined workspace, infrequent use of dental loupes, and utilization of dental chairs that were not ergonomically appropriate.

  3. Johnson CD, Green BN, Agaoglu M, Amorin-Woods L, Brown R, Byfield D, et al.
    J Chiropr Humanit, 2023 Dec;30:23-45.
    PMID: 37841068 DOI: 10.1016/j.echu.2023.08.001
    OBJECTIVE: This study aimed to (1) collect and analyze statements about how to celebrate chiropractic in the present and roles that chiropractors may fulfill in the future, (2) identify if there was congruence among the themes between present and future statements, and (3) offer a model about the chiropractic profession that captures its complex relationships that encompass its interactions within microsystem, mesosystem, exosystem, and macrosystem levels.

    METHODS: For this qualitative analysis, we used pattern and grounded theory approaches. A purposive sample of thought leaders in the chiropractic profession were invited to answer the following 2 open-ended questions: (1) envision the chiropractor of the future, and (2) recommendations on how to celebrate chiropractic. Information was collected during April 2023 using Survey Monkey. The information was entered into a spreadsheet and analyzed for topic clusters, which resulted in matching concepts with social-ecological themes. The themes between the responses to the 2 questions were analyzed for congruence. We used the Standards for Reporting Qualitative Research to report our findings.

    RESULTS: Of the 54 experts invited, 32 (59%) participated. Authors represented 7 countries and have a median of 32 years of chiropractic experience, with a range of 5 to 51 years. Nineteen major topics in the future statements and 23 major topics in statements about celebrating chiropractic were combined in a model. The topics were presented using the 4 levels of the social-ecological framework. Individual (microsystem): chiropractors are competent, well-educated experts in spine and musculoskeletal care who apply evidence-based practices, which is a combination of the best available evidence, clinical expertise, and patient values. Interpersonal relationships (mesosystem): chiropractors serve the best interests of their patients, provide person-centered care, embrace diversity, equity, and inclusion, consider specific health needs and the health of the whole person. Community (exosystem): chiropractors provide care within integrated health care environments and in private practices, serve the best interests of the public through participation in their communities, participate through multidisciplinary collaboration with and within the health care system, and work together as a profession with a strong professional identity. Societal (macrosystem): chiropractors contribute to the greater good of society and participate on a global level in policy, leadership, and research. There was concordance between both the future envisioning statements and the present celebration recommendations, which suggest logical validity based on the congruence of these concepts.

    CONCLUSION: A sample of independent views, including the perceptions from a broad range of chiropractic thought leaders from various backgrounds, philosophies, diversity characteristics, and world regions, were assembled to create a comprehensive model of the chiropractic profession. The resulting model shows an array of intrinsic values and provides the roles that chiropractors may provide to serve patients and the public. This study offers insights into the roles that future chiropractors may fulfill and how these are congruent with present-day values. These core concepts and this novel model may have utility during dialogs about identity, applications regarding chiropractic in policy, practice, education, and research, and building positive relationships and collaborations.

  4. Lam JC, Chai JY, Wong YL, Tan NW, Ha CT, Chan MY, et al.
    Ann Acad Med Singap, 2015 Nov;44(11):530-4.
    PMID: 27089960
    INTRODUCTION: Treatment of acute lymphoblastic leukaemia (ALL) using intensive chemotherapy has resulted in high cure rates but also substantial morbidity. Infective complications represent a significant proportion of treatment-related toxicity. The objective of this study was to describe the microbiological aetiology and clinical outcome of episodes of chemotherapy-induced febrile neutropaenia in a cohort of children treated for ALL at our institution.

    MATERIALS AND METHODS: Patients with ALL were treated with either the HKSGALL93 or the Malaysia-Singapore (Ma-Spore) 2003 chemotherapy protocols. The records of 197 patients who completed the intensive phase of treatment, defined as the period of treatment from induction, central nervous system (CNS)-directed therapy to reinduction from June 2000 to January 2010 were retrospectively reviewed.

    RESULTS: There were a total of 587 episodes of febrile neutropaenia in 197 patients, translating to an overall rate of 2.98 episodes per patient. A causative pathogen was isolated in 22.7% of episodes. An equal proportion of Gram-positive bacteria (36.4%) and Gram-negative bacteria (36.4%) were most frequently isolated followed by viral pathogens (17.4%), fungal pathogens (8.4%) and other bacteria (1.2%). Fungal organisms accounted for a higher proportion of clinically severe episodes of febrile neutropaenia requiring admission to the high-dependency or intensive care unit (23.1%). The overall mortality rate from all episodes was 1.5%.

    CONCLUSION: Febrile neutropaenia continues to be of concern in ALL patients undergoing intensive chemotherapy. The majority of episodes will not have an identifiable causative organism. Gram-positive bacteria and Gram-negative bacteria were the most common causative pathogens identified. With appropriate antimicrobial therapy and supportive management, the overall risk of mortality from febrile neutropaenia is extremely low.

  5. Lekhraj Rampal GR, Mohd Sidik S, Rampal S, Daniel Wong YJ, Chow PL, Liew JS, et al.
    Malays J Nutr, 2007 Mar;13(1):1-8.
    PMID: 22692184 MyJurnal
    Overweight and obesity place children and adolescents at increased risk of significant health problems, both during their early life and adult life. A cross sectional study was carried out to determine the prevalence of overweight among secondary school students aged 13-17 years in the Klang district and to determine the association between overweight and age, sex, ethnicity, religion and blood pressure. Random cluster proportionate to size sampling technique was used to select the respondents. Weight was recorded using TANITA model HD-309 and height was measured using SECA Body meter Model 208. A mercury sphygmomanometer was used to measure blood pressure manually. Statistical analysis was carried out using SPSS version 13. Out of the 3,333 respondents, 11.4% were found to be at risk of overweight and 8.2% were overweight. The prevalence of overweight was significantly higher in the males (10.6%) as compared to females (6.0%). Prevalence of overweight was highest in Malays (10.7%) followed by the Indians (7.1%) and the Chinese (5.9%). Prevalence of 'risk of overweight' was highest in the Indians (13.7%) followed by Chinese (12.0%) and Malays (9.8%). There was a moderate direct significant relationship between overweight and systolic blood pressure (r=0.5, r2=0.25, p<0.001) and also diastolic blood pressure (r=0.42, r2=0.18, p<0.001). The relationship between BMI and overweight was very weak (r=0.11, r2=0.01 and df=3331, p<0.001). In conclusion the prevalence of overweight among the secondary school students is high and there is a need for a comprehensive integrated population-based intervention program.
  6. Liew SY, Khaw KY, Murugaiyah V, Looi CY, Wong YL, Mustafa MR, et al.
    Phytomedicine, 2015 Jan 15;22(1):45-8.
    PMID: 25636869 DOI: 10.1016/j.phymed.2014.11.003
    Nine monoterpenoid indole alkaloids; naucletine (1), angustidine (2), nauclefine (3), angustine (4), naucline (5), angustoline (6), harmane (7), 3,14-dihydroangustoline (8), strictosamide (9) and one quinoline alkaloid glycoside; pumiloside (10) from Nauclea officinalis were tested for cholinesterase inhibitory activity. All the alkaloids except for pumiloside (10) showed strong to weak BChE inhibitory effect with IC50 values ranging between 1.02-168.55 μM. Angustidine (2), nauclefine (3), angustine (4), angustoline (6) and harmane (7) showed higher BChE inhibiting potency compared to galanthamine. Angustidine (2) was the most potent inhibitor towards both AChE and BChE. Molecular docking (MD) studies showed that angustidine (2) docked deep into the bottom gorge of hBChE and formed hydrogen bonding with Ser 198 and His 438. Kinetic study of angustidine (2) on BChE suggested a mixed inhibition mode with an inhibition constant (Ki) of 6.12 μM.
  7. Lim JJ, Lim YYE, Ng JY, Malipeddi P, Ng YT, Teo WY, et al.
    World Allergy Organ J, 2022 Dec;15(12):100722.
    PMID: 36438192 DOI: 10.1016/j.waojou.2022.100722
    BACKGROUND: Atopic Dermatitis (AD) is a highly pruritic, chronic-recurrent inflammatory skin condition associated with erythematous lesions that affect a significant proportion of the population. Although AD is a non-communicable disease, it can cause pain, unbearable itchiness, sleep disturbance, loss of work productivity, and reduced quality of life. As a heterogeneous disease, AD is influenced by multiple genes and environmental triggers. As such, it is imperative to gain a deeper insight into the intricate gene-environment relationship that results in the manifestation of AD.

    METHODS: There are 3 objectives in our study. We first aim to update the epidemiological status of AD amongst young adults in Singapore and Malaysia, in particular amongst the Chinese ethnic background. Next, we re-evaluated the possible associated risk factors, identified in our previous meta-analysis and review studies, on the current cohort. Finally, we described here a detailed disease presentation and symptoms profile of our Singapore and Malaysia Cross-Sectional Genetics Epidemiology Study (SMCGES) cohort, which forms the base population for the discovery of associated genetic factors in relation to asthma, allergic diseases and skin conditions. Based on a skin prick test (SPT) and investigator-administered medical history responses, we assessed the AD profiles of 11 494 participants and the significant modifiable and non-modifiable factors associated with disease presentation.

    RESULTS: The prevalence of AD in the combined population was 13.5%. Chronic and moderate/severe AD were observed in 35.5% and 40.5% of the individuals with AD, respectively. Family history of atopic diseases, prior history of drug allergies, a history of acne, increased household family monthly income, higher number of individuals in the shared household, parental education, sedentary lifestyle, physical activities, alcoholic consumption, and even quality of diet was significantly associated with AD presentation, chronicity, and severity. Among all the factors evaluated, family and personal history of atopic diseases imposed the strongest associated risk.

    CONCLUSIONS: These findings supported our previous review studies and affirmed that familial history or genetic factors critically influence the development of AD in our population and environment. Environmental and other modifiable factors can also trigger AD throughout the lifetime of individuals who have especially inherited the atopic disease disposition. A better understanding of how these risk factors affect AD individuals in our population can facilitate disease surveillance, monitor disease control, and serve as a description for our future genetic epidemiology studies.

  8. Lim JJ, Lim YYE, Ng JY, Malipeddi P, Ng YT, Teo WY, et al.
    Dermatology, 2024;240(1):77-84.
    PMID: 37666213 DOI: 10.1159/000533942
    BACKGROUND: We see increasing evidence that dietary and nutrients factors play a pivotal role in allergic diseases and recent global findings suggest that dietary habits influence the pathogenesis of atopic dermatitis (AD). Frequent consumption of fast food diets is associated with AD development. Despite the rising prevalence of AD in Asia, efforts in investigating the role of dietary habits and AD in adults are still lacking.

    METHODS: We evaluated the association between the dietary intake of 16 food types and AD manifestations using our Singapore/Malaysia Cross-sectional Genetics Epidemiology Study (SMCGES) population. Dietary habits profiles of 11,494 young Chinese adults (1,550 AD cases/2,978 non-atopic controls/6,386 atopic controls) were assessed by an investigator-administered questionnaire. AD cases were further evaluated for their chronicity (550 chronic) and severity (628 moderate-to-severe). Additionally, we derived a novel food index, Quality of Diet based on Glycaemic Index Score (QDGIS), to examine the association between dietary intake of glycaemic index (GI) and various AD phenotypes.

    RESULTS: The majority of AD subjects are distributed in the good (37.1%) and moderate (36.2%) QDGIS classes. From the multivariable analyses for age and gender, a moderate QDGIS class was significantly associated with a lower odds of AD (adjusted odds ratio (AOR): 0.844; 95% confidence interval (CI): 0.719-0.991; p < 0.05) and moderate-to-severe AD (AOR: 0.839; 95% CI: 0.714-0.985; p < 0.05). A good QDGIS class was only significantly associated with a lower odds of chronic AD (AOR: 0.769; 95% CI: 0.606-0.976; p < 0.05). Among high GI foods, frequent consumption of burgers/fast food was strongly associated with an increased risk of chronic and moderate-to-severe AD. Among low GI foods, increased intake frequencies of fruits, vegetables, and pulses decreased the odds of AD. Finally, we identified significant associations between frequent seafood, margarine, butter, and pasta consumption with an increased odds of AD despite them having little GI values.

    CONCLUSION: While genetic components are well-established in their risks associated with increased AD prevalence, there is still a lack of a focus epidemiology study associating dietary influence with AD. Based on the first allergic epidemiology study conducted here in Singapore and Malaysia, it laid the groundwork to guide potential dietary interventions from changing personal dietary habits.

  9. Looi CY, Moharram B, Paydar M, Wong YL, Leong KH, Mohamad K, et al.
    PMID: 23837445 DOI: 10.1186/1472-6882-13-166
    Centratherum anthelminticum (L.) Kuntze (scientific synonyms: Vernonia anthelmintica; black cumin) is one of the ingredients of an Ayurvedic preparation, called "Kayakalp", commonly applied to treat skin disorders in India and Southeast Asia. Despite its well known anti-inflammatory property on skin diseases, the anti-cancer effect of C. anthelminticum seeds on skin cancer is less documented. The present study aims to investigate the anti-cancer effect of Centratherum anthelminticum (L.) seeds chloroform fraction (CACF) on human melanoma cells and to elucidate the molecular mechanism involved.
  10. Narrima P, Paydar M, Looi CY, Wong YL, Taha H, Wong WF, et al.
    PMID: 24808916 DOI: 10.1155/2014/248103
    Persea declinata (Bl.) Kosterm is a member of the Lauraceae family, widely distributed in Southeast Asia. It is from the same genus with avocado (Persea americana Mill), which is widely consumed as food and for medicinal purposes. In the present study, we examined the anticancer properties of Persea declinata (Bl.) Kosterm bark methanolic crude extract (PDM). PDM exhibited a potent antiproliferative effect in MCF-7 human breast cancer cells, with an IC50 value of 16.68 µg/mL after 48 h of treatment. We observed that PDM caused cell cycle arrest and subsequent apoptosis in MCF-7 cells, as exhibited by increased population at G0/G1 phase, higher lactate dehydrogenase (LDH) release, and DNA fragmentation. Mechanistic studies showed that PDM caused significant elevation in ROS production, leading to perturbation of mitochondrial membrane potential, cell permeability, and activation of caspases-3/7. On the other hand, real-time PCR and Western blot analysis showed that PDM treatment increased the expression of the proapoptotic molecule, Bax, but decreased the expression of prosurvival proteins, Bcl-2 and Bcl-xL, in a dose-dependent manner. These findings imply that PDM could inhibit proliferation in MCF-7 cells via cell cycle arrest and apoptosis induction, indicating its potential as a therapeutic agent worthy of further development.
  11. Paydar M, Kamalidehghan B, Wong YL, Wong WF, Looi CY, Mustafa MR
    Drug Des Devel Ther, 2014;8:719-33.
    PMID: 24944509 DOI: 10.2147/DDDT.S58178
    To date, plants have been the major source of anticancer drugs. Boldine is a natural alkaloid commonly found in the leaves and bark of Peumus boldus. In this study, we found that boldine potently inhibited the viability of the human invasive breast cancer cell lines, MDA-MB-231 (48-hour IC₅₀ 46.5±3.1 μg/mL) and MDA-MB-468 (48-hour IC₅₀ 50.8±2.7 μg/mL). Boldine had a cytotoxic effect and induced apoptosis in breast cancer cells as indicated by a higher amount of lactate dehydrogenase released, membrane permeability, and DNA fragmentation. In addition, we demonstrated that boldine induced cell cycle arrest at G2/M phase. The anticancer mechanism is associated with disruption of the mitochondrial membrane potential and release of cytochrome c in MDA-MB-231. Boldine selectively induced activation of caspase-9 and caspase-3/7, but not caspase-8. We also found that boldine could inhibit nuclear factor kappa B activation, a key molecule in tumor progression and metastasis. In addition, protein array and Western blotting analysis showed that treatment with boldine resulted in downregulation of Bcl-2 and heat shock protein 70 and upregulation of Bax in the MDA-MB-231 cell line. An acute toxicity study in rats revealed that boldine at a dose of 100 mg/kg body weight was well tolerated. Moreover, intraperitoneal injection of boldine (50 or 100 mg/kg) significantly reduced tumor size in an animal model of breast cancer. Our results suggest that boldine is a potentially useful agent for the treatment of breast cancer.
  12. Paydar M, Wong YL, Wong WF, Hamdi OA, Kadir NA, Looi CY
    J Food Sci, 2013 Dec;78(12):T1940-7.
    PMID: 24279333 DOI: 10.1111/1750-3841.12313
    Edible bird nests (EBNs) are important ethnomedicinal commodity in the Chinese community. Recently, But and others showed that the white EBNs could turn red by vapors from sodium nitrite (NaNO2) in acidic condition or from bird soil, but this color-changing agent remained elusive. The aim of this study was to determine the prevalence of nitrite and nitrate contents and its affects on EBN's color. EBNs were collected from swiftlet houses or caves in Southeast Asia. White EBNs were exposed to vapor from NaNO2 in 2% HCl, or bird soil. The levels of nitrite (NO2-) and nitrate (NO3-) in EBNs were determined through ion chromatography analysis. Vapors from NaNO2 in 2% HCl or bird soil stained white bird nests to brown/red colors, which correlated with increase nitrite and nitrate levels. Moreover, naturally formed cave-EBNs (darker in color) also contained higher nitrite and nitrate levels compared to white house-EBNs, suggesting a relationship between nitrite and nitrate with EBN's color. Of note, we detected no presence of hemoglobin in red "blood" nest. Using infrared spectra analysis, we demonstrated that red/brown cave-EBNs contained higher intensities of C-N and N-O bonds compared to white house-EBNs. Together, our study suggested that the color of EBNs was associated with the prevalence of the nitrite and nitrate contents.
  13. Paydar M, Wong YL, Moharam BA, Wong WF, Looi CY
    Pak J Biol Sci, 2013 Oct 15;16(20):1212-5.
    PMID: 24506026
    Sanchezia speciosa, is a bushy shrub from Acanthaceae family which commonly grows in tropical areas of South and Central America. In this study, we employed MTT assay to test the cytotoxicity of that methanolic fraction of S. speciosa leaves on MCF-7 human breast cancer, SK-MEL-5 human malignant melanoma and human umbilical vein endothelial cells, HUVEC cells. The extract showed highest activity on MCF-7 and moderate cytotoxicity towards SK-MEL-5. In contrast, the extract demonstrated lowest cell growth inhibition activity on HUVEC cells, indicating better selectivity compare to standard drug, doxorubicin. In addition, we also performed ORAC assay to determine the radical scavenging capacity of methanolic extract of S. speciosa leaves. The extract exhibited nearly similar anti-oxidant activity as quercetin, suggesting S. speciosa leaves as a potential source of natural anti-oxidant. To the best of our knowledge, this is the first report on anti-oxidant and cytotoxic activity of S. speciosa.
  14. Reginald K, Wong YR, Shah SMR, Teh KF, Freddy Jalin EJ, Khan NA
    Microbes Infect, 2021 07 28;23(9-10):104876.
    PMID: 34332091 DOI: 10.1016/j.micinf.2021.104876
    BACKGROUND: Insects models are excellent models of the innate immune system, as they are free from the influences of vertebrate adaptive immunity. Crickets are hemimetabolous insects belonging to the order Orthopteran order that have not been as extensively characterized as other holometabolous insects, and may provide new insights into the insect immune responses. In this study, we aim to characterize the innate immune responses of the common house cricket, Acheta domesticus in response to a human pathogenic bacterium E. coli K1.

    METHODS: Crickets were injected with sterile buffer, live E. coli K1 or heat-killed E. coli K1. Physiological effects such as mortality and weight change of the crickets were determined 24-, 48- and 72-h post injection while immunological effects such as hemocyte counts, bacteremia, phenoloxidase and lysozyme activity of the crickets were measured at 2- and 24-h post-injection.

    RESULTS: The injection of E. coli K1 in crickets resulted in >85% mortality 3-days post injection, accompanied by significant weight loss. E. coli K1 injection caused a significant increase in both phenoloxidase and lysozyme activities in cricket hemolymphs 24-h post injection. Live E. coli K1 injected crickets resulted in a significant reduction in circulating hemocytes 24-h post injection which was not observed in other treatment groups. This was consistent with the resolution of bacteremia observed 24-h post infection in live E. coli K1 injected crickets.

    CONCLUSION: Our study provides new insights on the innate immune response to pathogenic E. coli K1 in a cricket model.

  15. Say YH, Heng AHS, Reginald K, Wong YR, Teh KF, Rawanan Shah SM, et al.
    BMC Public Health, 2021 03 27;21(1):601.
    PMID: 33773591 DOI: 10.1186/s12889-021-10681-4
    BACKGROUND: Acne vulgaris, a highly prevalent multifactorial inflammatory skin disease, can be categorised into different severity and scarring grades based on the type, number, and severity of lesions. While many epidemiology studies have investigated the risk factors for acne presentation, fewer studies have specifically studied the risk factors for acne severity and scarring. Therefore, this study investigated the prevalence of acne, acne severity and scarring grades, and their associated non-modifiable and modifiable epidemiological risk factors among Malaysian Chinese.

    METHODS: A total of 1840 subjects (1117 cases/723 controls) completed an investigator-administered questionnaire as part of a cross-sectional study, which include socio-demographics, familial history, lifestyle factors, dietary habits, and acne history. Acne cases were further evaluated for their severity (n = 1051) and scarring (n = 1052) grades by a trained personnel.

    RESULTS: Majority of the acne cases (up to 69%) had mild acne or Grade 1/2 scarring, while 21.6% had moderate/severe acne and 5.5% had Grade 3/4 scarring. Males had significantly higher risk of presenting with higher grades of acne scarring. Those who had acne, regardless of severity and scarring grades, had strong positive familial history (either in parents and/or sibling). Frequent consumption (most or all days) of foods that are commonly consumed during breakfast (butter, probiotic drinks, cereals and milk) decreased the risk for acne presentation and higher acne scarring, while periodic consumption (once/twice per week) of nuts and burgers/fast food decreased the risk for higher acne severity. Alcohol drinking was significantly associated with increased risk for acne presentation, while paternal, parental and household smoking were associated with reduced risk of more severe acne.

    CONCLUSIONS: In conclusion, positive familial history is a strong predisposing factor in influencing acne presentation, severity and scarring. Frequent consumption of foods that are commonly consumed during breakfast is protective against acne presentation.

  16. Shawish HB, Wong WY, Wong YL, Loh SW, Looi CY, Hassandarvish P, et al.
    PLoS One, 2014;9(6):e100933.
    PMID: 24977407 DOI: 10.1371/journal.pone.0100933
    BACKGROUND: The biological properties of thiosemicarbazone have been widely reported. The incorporation of some transition metals such as Fe, Ni and Cu to thiosemicarbazone complexes is known to enhance its biological effects. In this study, we incorporated nickel(II) ions into thiosemicarbazone with N4-substitution groups H3L (H; H3L1, CH3; H3L2, C6H5; H3L3 and C2H5; H3L4) and examined its potential anti-inflammatory activity.

    METHODOLOGY/PRINCIPAL FINDINGS: Four ligands (1-4) and their respective nickel-containing complexes (5-8) were synthesized and characterized. The compounds synthesized were tested for their effects on NF-κB nuclear translocation, pro-inflammatory cytokines secretion and NF-κB transactivation activity. The active compound was further evaluated on its ability to suppress carrageenan-induced acute inflammation in vivo. A potential binding target of the active compound was also predicted by molecular docking analysis.

    CONCLUSIONS/SIGNIFICANCE: Among all synthesized compounds tested, we found that complex [Ni(H2L1)(PPh3)]Cl (5) (complex 5), potently inhibited IκBα degradation and NF-κB p65 nuclear translocation in LPS-stimulated RAW264.7 cells as well as TNFα-stimulated HeLa S3 cells. In addition, complex 5 significantly down-regulated LPS- or TNFα-induced transcription of NF-κB target genes, including genes that encode the pro-inflammatory cytokines TNFα, IFNβ and IL6. Luciferase reporter assays confirmed that complex 5 inhibited the transactivation activity of NF-κB. Furthermore, the anti-inflammatory effect of complex 5 was also supported by its suppressive effect on carrageenan-induced paw edema formation in wild type C57BL/6 mice. Interestingly, molecular docking study showed that complex 5 potentially interact with the active site of IKKβ. Taken together, we suggest complex 5 as a novel NF-κB inhibitor with potent anti-inflammatory effects.

  17. Sio YY, Pang SL, Say YH, Teh KF, Wong YR, Shah SMR, et al.
    Mycopathologia, 2021 Oct;186(5):583-588.
    PMID: 34258653 DOI: 10.1007/s11046-021-00532-6
    Fungal spores and conidia are the major components of total airspora in the tropical Asia environment, and their sensitization patterns are often associated with allergic diseases such as asthma, allergic rhinitis (AR), and atopic dermatitis. Hence, we recruited a cross-sectional cohort of 9223 Singapore/Malaysia Chinese adults and assessed their sensitization against Curvularia lunata allergen using the skin prick test approach. A subset of this cohort (n = 254) was also screened for specific Immunoglobulin E (sIgE) titers against a panel of 11 fungal allergens. We found significant association of Curvularia lunata sensitization with the risk of asthma (OR = 1.66, 95% CI: 1.17-2.33; p = 0.00391) and AR (OR = 1.69, 95% CI: 1.18-2.41; p = 0.00396). Among asthmatic patients (n = 1680), Curvularia lunata sensitization also increased frequencies of wheezing symptoms (OR = 1.81, 95% CI: 1.05-2.96; p = 0.0239), general practitioner/specialist visits (OR = 2.37, 95% CI: 1.13-4.61; p = 0.0157), and other asthma-related exacerbation events (OR = 2.14, 95% CI: 1.04-4.10; p = 0.0289). In our serum cohort, sensitization to Aspergillus spp. was the most common fungal sensitization, with 23.6% (n = 60) had a class 3 and above sensitization (positive sensitization; sIgE titers of > 3.5 kU/L) against this allergen. Increasing sIgE titer against Aspergillus spp. was also correlated with increased AR risk and AR-related symptoms. In conclusion, our findings emphasize an important role of fungal sensitization in the manifestations of asthma and AR in the Southeast Asian Chinese population.
  18. Sio YY, Gan WL, Ng WS, Matta SA, Say YH, Teh KF, et al.
    Int Arch Allergy Immunol, 2023;184(10):1010-1021.
    PMID: 37336194 DOI: 10.1159/000530960
    INTRODUCTION: Previous studies have indicated the ERBB2 genetic variants in the 17q12 locus might be associated with asthma; however, the functional effects of these variants on asthma risk remain inconclusive. This study aimed to characterize the functional roles of asthma-associated ERBB2 single nucleotide polymorphisms (SNPs) in asthma pathogenesis by performing genetic association and functional analysis studies.

    METHODS: This study belongs to a part of an ongoing Singapore/Malaysia cross-sectional genetics and epidemiological study (SMCSGES). Genotype-phenotype associations were assessed by performing a genotyping assay on n = 4,348 ethnic Chinese individuals from the SMCSGES cohort. The phosphorylation levels of receptors and signaling proteins in the MAPK signaling cascades, including ErbB2, EGFR, and ERK1/2, were compared across the genotypes of asthma-associated SNPs through in vitro and ex vivo approaches.

    RESULTS: The ERBB2 tag-SNP rs1058808 was significantly associated with allergic asthma, with the allele "G" identified as protective against the disease (adjusted logistic p = 6.56 × 10-9, OR = 0.625, 95% CI: 0.544-0.718). The allele "G" of rs1058808 resulted in a Pro1170Ala mutation that results in lower phosphorylation levels of ErbB2 in HaCat cells (p < 0.001), whereas the overall ERBB2 mRNA expression and the phosphorylation levels of EGFR remained unaffected. In the SMCSGES cohort, individuals carrying the genotype "GG" of rs1058808 had lower phosphorylated ERK1/2 proteins in the MAPK signaling cascade. A lower phosphorylation level of ERK1/2 was also associated with reduced asthma risk.

    CONCLUSIONS: The present findings highlighted the involvement of a functional exonic variant of ERBB2 in asthma development via modulating the MAPK signaling cascade.

  19. Sio YY, Victoria Nanong GA, Lim JA, Matta SA, Say YH, Teh KF, et al.
    World Allergy Organ J, 2024 Jan;17(1):100853.
    PMID: 38235258 DOI: 10.1016/j.waojou.2023.100853
    BACKGROUND: Elaeis guineensis (Ela g, oil palm) pollen is one of the most predominant species of inhalant allergens in the tropical Southeast Asia region; however, its association with the manifestation of allergic diseases remains largely unexplored. This study aimed to determine the sensitization pattern of oil palm pollen and associate this with the risk and severity of allergic diseases.

    METHODS: Participants were recruited as a part of the Singapore and Malaysia cross-sectional genetic and epidemiological study (SMCSGES). Two independent cohorts were recruited: n = 564 serum samples were collected and serological assessment was performed against a panel of 16 crude inhalant allergens including house dust mite, pet, insect, pollen, and fungal allergens; n = 13 652 Singapore/Malaysia Chinese young adults were recruited and skin prick test was used to assess oil palm sensitization, which was tested for its association with the risk and severity of asthma, allergic rhinitis (AR), and atopic dermatitis (AD).

    RESULTS: The sensitization rate of oil palm pollen is 9.6% in the n = 564 Singapore/Malaysia cohort. In the n = 13 652 Singapore/Malaysia Chinese cohort, oil palm sensitization significantly associates with increased risks of asthma (p = 1.34x10-4), AR (p = 2.91x10-13), and AD (p = 6.95x10-7). Asthmatic patients with oil palm sensitization have increased risks of wheezing (p = 0.00995), nocturnal cough (p = 0.0122), and exacerbations (p = 0.00139) in the past 12 months. AR patients with oil palm sensitization also have an increased risk of developing moderate-to-severe symptoms (p = 0.00113).

    CONCLUSIONS: We have identified significant associations of oil palm sensitization with increased risks, exacerbations, and the severity of symptoms of allergic diseases in the tropical Southeast Asian region (Singapore/Malaysia).

  20. Sulaiman E, Alarami N, Wong YI, Lee WH, Al-Haddad A
    Dent Med Probl, 2018 10 18;55(3):275-279.
    PMID: 30328305 DOI: 10.17219/dmp/94656
    BACKGROUND: There is no sufficient literature on the effect of post location on endodontically treated premolar teeth with 2 roots.

    OBJECTIVES: The aim of the study was to evaluate the effect of fiber post location on fracture resistance and failure mode of endodontically treated premolars with 2 roots.

    MATERIAL AND METHODS: Fifty extracted maxillary first premolars with 2 roots were divided randomly into 5 groups. Group 1 was comprised of sound teeth, which received only metal crowns (control). Teeth from groups 2, 3, 4, and 5 were decoronated 2 mm above the cementoenamel junction (CEJ) and were endodontically treated. No post was placed in group 2 teeth. Teeth from groups 3, 4 and 5 were given a fiber post placed in the buccal canal, palatal canal, and both buccal and palatal canals, respectively. All teeth in groups 2, 3, 4, and 5 were built up with composite and full coverage metal crowns. A compressive static load was applied at an angle of 25° to the crowns with a crosshead speed of 0.5 mm/min, until fracture.

    RESULTS: One-way analysis of variance (ANOVA) showed significant differences among the groups (p = 0.002). A post hoc test showed significantly lower fracture resistance of group 4 compared to group 5 (p = 0.011). Furthermore, group 2 had significantly less fracture resistance compared to group 1 (p = 0.021) and group 5 (p = 0.002). According to Fisher's exact test, different post locations are non-significantly associated with fracture mode (p = 0.256).

    CONCLUSIONS: Fiber post location has a significant effect on fracture resistance of severely damaged, endodontically treated maxillary premolars with 2 roots. However, post placement in the palatal root is preferred, as it maintains the restorability of the tooth.

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