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Biological properties of sodium alkyl methyl ester sulfonate/alkyltrimethylammonium bromide surfactant mixtures

Wong SP, Lim WH, Cheng SF, Chuah CH

Colloids Surf B Biointerfaces, 2012 Jan 1;89:48-52.
PMID: 21937202 DOI: 10.1016/j.colsurfb.2011.08.021

Quaternary ammonium compounds (QACs) are commonly used as disinfectant in medical care, food industry, detergents and glue industries. This is due to a small concentration of QACs is sufficient to inhibit the growth of various bacteria strains. In this work, the inhibitive power of cationic surfactants, alkyltrimethylammonium bromide (C(n)TAB) in the presence of anionic surfactants, sodium alkyl methyl ester α-sulfonate (C(n)MES) was studied. The growth inhibition test with gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria were used to determine the toxicity of single and mixed surfactants. Results from this work showed that certain mixed surfactants have lower minimum inhibition concentration (MIC) as compared to the single C(n)TAB surfactants. Besides that, it was also found that alkyl chain length and the mixing ratios of the surfactants play a significant role in determining the mixture inhibitive power.
Arborisidine and Arbornamine, Two Monoterpenoid Indole Alkaloids with New Polycyclic Carbon-Nitrogen Skeletons Derived from a Common Pericine Precursor

Wong SP, Chong KW, Lim KH, Lim SH, Low YY, Kam TS

Org. Lett., 2016 Apr 1;18(7):1618-21.
PMID: 27033525 DOI: 10.1021/acs.orglett.6b00478

Two new monoterpene indole alkaloids, characterized by previously unencountered natural product skeletons, viz., arborisidine (1), incorporating indolizidine and cyclohexanone moieties fused to an indole unit, and arbornamine (2), incorporating an unprecedented 6/5/6/5/6 "arbornane" skeleton (distinct from the eburnan or tacaman skeleton), were isolated from a Malayan Kopsia arborea. The structures of the alkaloids were determined based on analysis of the NMR and MS data. Possible biogenetic pathways to these alkaloids from a common pericine precursor (3) are presented.
Arboridinine, a Pentacyclic Indole Alkaloid with a New Cage Carbon-Nitrogen Skeleton Derived from a Pericine Precursor

Wong SP, Gan CY, Lim KH, Ting KN, Low YY, Kam TS

Org. Lett., 2015 Jul 17;17(14):3628-31.
PMID: 26183592 DOI: 10.1021/acs.orglett.5b01757

A new monoterpene indole alkaloid characterized by an unprecedented pentacyclic cage skeleton, arboridinine (1), was isolated from a Malaysian Kopsia species. The structure and absolute configuration of the alkaloid were determined based on NMR, MS, and X-ray diffraction analysis. A possible biogenetic pathway from a pericine precursor is presented.
A Cytotoxic Indole Characterized by Incorporation of a Unique Carbon-Nitrogen Skeleton and Two Pentacyclic Corynanthean Alkaloids Incorporating a Substituted Tetrahydrofuranone Ring from Kopsia arborea

Wong SK, Wong SP, Sim KS, Lim SH, Low YY, Kam TS

J Nat Prod, 2019 07 26;82(7):1902-1907.
PMID: 31241923 DOI: 10.1021/acs.jnatprod.9b00255

Three new alkaloids were isolated from the bark extract of the Malayan Kopsia arborea, viz., arbophyllidine (1), an unusual pentacyclic, monoterpenoid indole characterized by an absence of oxygen atoms and incorporating a new carbon-nitrogen skeleton, and arbophyllinines A (2) and B (3), two pentacyclic corynanthean alkaloids incorporating a hydroxyethyl-substituted tetrahydrofuranone ring. The structures of the alkaloids were deduced based on analysis of the MS and NMR data and confirmed by X-ray diffraction analyses. The absolute configuration of arbophyllidine (1) was established based on experimental and calculated ECD data, while that of arbophyllinine A was based on X-ray diffraction analysis (Cu Kα). A reasonable biosynthetic route to arbophyllidine (1) from a pericine precursor is presented. Arbophyllidine (1) showed pronounced in vitro growth inhibitory activity against the HT-29 human cancer cell line with IC50 6.2 μM.
Fluctuation of BCR-ABL1 qPCRIS level beyond 0.1%IS after stopping tyrosine kinase inhibitor in chronic myeloid leukaemia patients with deep molecular response for at least two years

Kuan JW, Chang KM, Phan CL, Wong SP, Lim SM, Toh SG, et al.

Med J Malaysia, 2021 May;76(3):414-416.
PMID: 34031342

Fluctuation of BCR-ABL1 real-time quantitative polymerase chain reaction in International Scale (qPCRIS) level below major molecular response (MMR) (0.1%IS) is a known phenomenon after stopping tyrosine kinase inhibitor (TKI) in chronic myeloid leukaemia (CML) patients who are attempting treatment free remission (TFR). We report here four cases of fluctuation beyond MMR during conduct of a Malaysia Stop TKI Trial (MSIT) to examine the validity of the commonly used relapse criterion - loss of MMR for one reading - aiming to provide evidence in setting relapse criteria for future CML patients who want to attempt TFR.
Oral and Gut Microbiota Dysbiosis is Associated with Mucositis Severity in Autologous Hematopoietic Stem Cell Transplantation: Evidence from an Asian Population

Wong SP, Er YX, Tan SM, Lee SC, Rajasuriar R, Lim YAL

Transplant Cell Ther, 2023 Oct;29(10):633.e1-633.e13.
PMID: 37422196 DOI: 10.1016/j.jtct.2023.06.016

Mucositis is a debilitating complication of hematopoietic stem cell transplantation (HSCT). It is unclear how changes in the composition of microbiota, which are modulated by geographical location and ethnicity, may influence immune regulation leading to the development of mucositis, and the study of both oral and gut microbiota in a single population of autologous HSCT in the Asian region is lacking. The present study aimed to characterize the oral and gut microbiota changes, and the impact on both oral and lower gastrointestinal (GI) mucositis, with associated temporal changes in a population of adult recipients of autologous HSCT. Autologous HSCT recipients age ≥18 years were recruited from Hospital Ampang, Malaysia, between April 2019 and December 2020. Mucositis assessments were conducted daily, and blood, saliva, and fecal samples were collected prior to conditioning, on day 0, and at 7 days and 6 months post-transplantation. Longitudinal differences in alpha diversity and beta diversity were determined using the Wilcoxon signed-rank test and permutational multivariate analysis of variance, respectively. Changes in relative abundances of bacteria across time points were assessed using the microbiome multivariate analysis by linear models function. The combined longitudinal effects of clinical, inflammatory, and microbiota variables on mucositis severity were measured using the generalized estimating equation. Among the 96 patients analyzed, oral mucositis and diarrhea (representing lower GI mucositis) occurred in 58.3% and 95.8%, respectively. Alpha and beta diversities were significantly different between sample types (P < .001) and across time points, with alpha diversity reaching statistical significance at day 0 in fecal samples (P < .001) and at day +7 in saliva samples (P < .001). Diversities normalized to baseline by 6 months post-transplantation. Significant microbiota, clinical, and immunologic factors were associated with increasing mucositis grades. Increasing relative abundances of saliva Paludibacter, Leuconostoc, and Proteus were associated with higher oral mucositis grades, whereas increasing relative abundances of fecal Rothia and Parabacteroides were associated with higher GI mucositis grades. Meanwhile, increasing relative abundances of saliva Lactococcus and Acidaminococcus and fecal Bifidobacterium were associated with protective effects against worsening oral and GI mucositis grades, respectively. This study provides real-world evidence and insights into the dysbiosis of the microbiota in patients exposed to conditioning regimen during HSCT. Independent of clinical and immunologic factors, we demonstrated significant associations between relative bacteria abundances with the increasing severity of oral and lower GI mucositis. Our findings offer a potential rationale to consider the inclusion of preventive and restorative measures targeting oral and lower GI dysbiosis as interventional strategies to ameliorate mucositis outcome in HSCT recipients.
Prospective longitudinal analysis of clinical and immunological risk factors associated with oral and gastrointestinal mucositis following autologous stem cell transplant in adults

Wong SP, Tan SM, Lee CS, Law KB, Lim YAL, Rajasuriar R

Support Care Cancer, 2023 Jul 27;31(8):494.
PMID: 37498423 DOI: 10.1007/s00520-023-07947-5

PURPOSE: The study aimed to characterize the incidence of both oral and gastrointestinal (GI) mucositis, its' associated temporal changes in local and systemic pro-inflammatory cytokines, and to explore predictive clinical and immunological factors associated with their occurrences in hematopoietic stem cell transplant (HSCT).
METHODS: Autologous HSCT patients aged 18 years old and above were recruited from Hospital Ampang, Malaysia, between April 2019 to December 2020. Mucositis assessments were conducted daily, whilst blood and saliva were collected prior to conditioning regimen, on Day 0, Day+7 and 6-month. Baseline and inflammatory predictors in a repeated time measurement of moderate-severe mucositis were assessed by multiple logistic regression and generalized estimating equations, respectively.
RESULTS: Of the 142 patients analyzed, oral mucositis and diarrhea (representing GI mucositis) were reported as 68.3% and 95.8%, respectively. Predictive factors for moderate-severe oral mucositis were BEAM or busulphan-based regimens (odds ratio (OR)=9.2, 95% confidence interval (CI)=1.16-72.9, p-value (p) = 0.005) and vomiting (OR=4.6, 95% CI 1.68-12.3, p = 0.004). Predictive factors for moderate-severe GI mucositis were BEAM or busulphan-based regimens (OR=3.9, 95% CI 1.05-14.5, p = 0.023), female sex (OR = 3.3, 95% CI 1.43-7.44, p = 0.004) and body mass index (OR=1.08, 95% CI 1.02-1.15, p = 0.010). Cytokines analyses were performed in 96 patients. Saliva and plasma interleukin-6 (OR=1.003, 95% CI 1.001-1.004, p < 0.001 and OR=1.01, 95% CI 1.001-1.015, p = 0.029), and plasma tumor necrosis factor-alpha (OR=0.91, 95% CI 0.85-0.99, p = 0.019) were predictive of moderate-severe oral mucositis in a time-dependent model.
CONCLUSION: This study provides real-world evidence and insights into patient- and treatment-related factors affecting oral and GI mucositis in HSCT.
Fulltext Psychometric evaluation of Oral Mucositis Daily Questionnaire: A cross-cultural adaptation of the Malay version in multiethnic adult autologous stem cell transplant

Wong SP, Tan SM, Danaee M, Muhamad K, Jamal M, Islahudin F, et al.

Asia Pac J Oncol Nurs, 2023 Feb;10(2):100180.
PMID: 36880090 DOI: 10.1016/j.apjon.2022.100180

OBJECTIVE: Mucositis is one of the most feared side effects of cancer treatment. Psychometric analysis of a patient self-assessment score, the oral mucositis daily questionnaire in Malay (OMDQ-Mal) and its construct validity by means of confirmatory factor analysis (CFA) is lacking. This research aimed to test the validity and reliability of OMDQ-Mal.
METHODS: A total of 114 autologous stem-cell transplantation patients aged ≥ 18 years old at a national hematology center in Malaysia from April 2019 to December 2020 completed OMDQ-Mal concurrently with physician scores. Internal consistency and reproducibility were determined by Cronbach alpha and intraclass correlation coefficient, respectively. Correlations with physician scores were determined by Spearman correlation. Discriminative validity and construct validity were determined by Mann-Whitney U and CFA, respectively.
RESULTS: OMDQ-Mal demonstrated high internal consistency (α = 0.874). Test-retest reliability between paired days were moderate to excellent (95% CI = 0.676-0.953). Items in OMDQ-Mal had moderate to strong correlations with physician scores (ρ = 0.503-0.721). Discriminative validity indicated that the scores of scales were significantly different between participants with severe and mild conditions. Construct validity results of loading factors 0.708-0.952; composite reliability 0.879-0.974; average variant extracted 0.710-0.841; and heterotrait-monotrait ratio 0.528 established the convergent and divergent validity.
CONCLUSIONS: In conclusion, the OMDQ-Mal, which captured important quality of life responses, demonstrated adequate validity and reliability. This was supported by a two-component model CFA. The strong correlation of OMDQ-Mal with both physician scores indicated its potential as a comprehensive patient-reported outcome measure of mucositis of the entire alimentary tract.
A randomized double blind control trial comparing filgrastim and pegfilgrastim in cyclophosphamide peripheral blood hematopoietic stem cell mobilization

Kuan JW, Su AT, Wong SP, Sim XY, Toh SG, Ong TC, et al.

Transfus Apher Sci, 2015 Oct;53(2):196-204.
PMID: 25910537 DOI: 10.1016/j.transci.2015.03.017

There are few randomized trials comparing filgrastim and pegfilgrastim in peripheral blood stem cell mobilization (PBSCM). None of the trials studied the effects of the timing of pegfilgrastim administration on the outcomes of mobilization. We conducted a randomized triple blind control trial comparing the outcomes of filgrastim 5 µg/kg daily from day 3 onwards, 'early' pegfilgrastim 6 mg on day 3 and 'delayed' pegfilgrastim 6 mg on day 7 in cyclophosphamide PBSCM in patients with no previous history of mobilization. Peripheral blood (PB) CD34+ cell count was checked on day 8 and day 11 onward. Apheresis was started when PB CD34+ ≥ 10/µl from day 11 onward. The primary outcome was the successful mobilization rate, defined as cumulative collection of ≥2 × 10(6)/kg CD34+ cells in three or less apheresis. The secondary outcomes were the day of neutrophil and platelet engraftment post transplantation. There were 156 patients randomized and 134 patients' data analyzed. Pegfilgrastim 6 mg day 7 produced highest percentage of successful mobilization, 34 out of 48 (70.8%) analyzed patients, followed by daily filgrastim, 28 out of 44 (63.6%) and day 3 pegfilgrastim, 20 out of 42 (47.6%) (p = 0.075). Pegfilgrastim day 7 and daily filgrastim reported 1.48 (p = 0.014) and 1.49 (p = 0.013) times higher successful mobilization rate respectively as compared to pegfilgrastim day 3 after adjusting for disease, gender and exposure to myelotoxic agent. Multiple myeloma patients were three times more likely to achieve successful mobilization as compared to acute leukemia or lymphoma patients. Pegfilgrastim avoided the overshoot of white cells compared to filgrastim. There was no difference in the duration of both white cells and platelet recovery post transplantation between the three interventional arms.