Displaying all 13 publications

Abstract:
Sort:
  1. Wan Safwani WK, Wong CW, Yong KW, Choi JR, Mat Adenan NA, Omar SZ, et al.
    Cytotechnology, 2016 Oct;68(5):1859-72.
    PMID: 26728363 DOI: 10.1007/s10616-015-9939-9
    The need to have a better and safer culture condition for expansion of human mesenchymal stem cells (MSCs) is crucial particularly to prevent infection and immune rejection. This is normally associated with the use of animal-based serum in the culture media for cell expansion. The aim of this study is to investigate alternative culture conditions which may provide better and safer environment for cell growth. In the present study, human adipose-derived stem cells (ASCs) at passage 3 were subjected to treatment in 4 conditions: (1) 21 % O2 with fetal bovine serum (FBS), (2) 21 % O2 without FBS, (3) 2 % O2 with FBS and (4) 2 % O2 without FBS followed by subsequent analysis of their phenotype, viability and functionality. We observed that ASCs cultured in all conditions present no significant phenotypic changes. It was found that ASCs cultured in 2 % O2 without serum showed an increase in viability and growth to a certain extent when compared to those cultured in 21 % O2 without serum. However, ASCs cultured in 2 % O2 without serum displayed a relatively low adipogenic and osteogenic potential. On the other hand, interestingly, there was a positive enhancement in chondrogenic differentiation of ASCs cultured in 21 % O2 without serum. Our findings suggest that different culture conditions may be suitable for different indications. In summary, ASCs cultured in serum-free condition can still survive, proliferate and undergo subsequent adipogenic, osteogenic and chondrogenic differentiation. Therefore, FBS is feasible to be excluded for culture of ASCs, which avoids clinical complications.
  2. Tsai ASH, Yeo BSY, Anaya Alaminos R, Wong CW, Tham CC, Fang SK, et al.
    Asia Pac J Ophthalmol (Phila), 2022 09 14;11(5):434-440.
    PMID: 37494222 DOI: 10.1097/APO.0000000000000556
    PURPOSE: To describe ophthalmology training experiences across the Asia-Pacific (APAC).

    DESIGN: Survey study.

    METHODS: We utilized an anonymous online survey, which was previously validated and conducted in Europe, through Young Ophthalmologist leaders from the national member societies of the Asia-Pacific Academy of Ophthalmology (APAO) from September 2019 to July 2021. Responses were based on a 5-point Likert scale (where applicable) and data were analyzed using Microsoft Excel. Our main outcome measures were differences between regions, that is, Southeast Asia (SEA) and Western Pacific (WP); and seniority, that is, trainees/junior ophthalmologists and senior ophthalmologists.

    RESULTS: We collated 130 responses representing 20 regions in the APAC region. The year of completion of ophthalmic training ranged from 1999 to 2024. The mean duration of training was 3.7±1.0 years. Most (98/130, 75%) indicated an interest for a common training standard across the APAC. Comparing SEA and WP trainees, both regions had similar working environments, but those in SEA reported significantly lower remuneration than their counterparts in WP ($600 vs $3000, P <0.05). WP trainees performed more phacoemulsification surgeries (76 WP vs 19 SEA), while SEA trainees conducted more manual small incision cataract surgeries (157 WP vs 1.5 SEA per duration of training). Senior ophthalmologists performed more cataract surgeries (210.9 senior ophthalmologists vs 40.1 junior ophthalmologists). Trainees had less confidence in medical competency areas such as interpreting an electroretinogram/visual evoked potential/electrooculogram (SEA=1.8, WP=2.1) and conducting an angiography (SEA=2.8, WP=3.4).

    CONCLUSIONS: Our study highlighted heterogeneity among ophthalmology training experiences in the APAC region, with the majority indicating an interest in a common training standard.

  3. Wu PY, Fung AT, Dave VP, Iu LPL, Sjahreza E, Chaikitmongkol V, et al.
    Clin Exp Ophthalmol, 2023 Aug;51(6):585-597.
    PMID: 37170410 DOI: 10.1111/ceo.14236
    BACKGROUND: To assess rhegmatogenous retinal detachment (RRD) surgery trends and training among young ophthalmologists (YOs, vitreoretinal fellows or attendings/consultants with ≤10 years of independent practice) and the impact of the COVID-19 pandemic.

    METHODS: An anonymous online survey was completed by 117 YOs in the Asia-Pacific regarding their RRD surgery experiences in 2021-2022.

    RESULTS: To achieve a 90% probability of surgical competency, 91 vitrectomy and 34 scleral buckling (SB) completions during fellowship were needed. In total, 49 (41.9%) YOs had fellowship affected by COVID-19. In the COVID versus pre-COVID era, however, the volume of SB completions per fellowship year decreased significantly (median [IQR] 3.3 [1.5, 9] vs. 13 [6.5, 23]; p 

  4. Chong KK, Wong CW, Siaw FL, Yew TK, Ng SS, Liang MS, et al.
    Sensors (Basel), 2009;9(10):7849-65.
    PMID: 22408483 DOI: 10.3390/s91007849
    A novel on-axis general sun-tracking formula has been integrated in the algorithm of an open-loop sun-tracking system in order to track the sun accurately and cost effectively. Sun-tracking errors due to installation defects of the 25 m(2) prototype solar concentrator have been analyzed from recorded solar images with the use of a CCD camera. With the recorded data, misaligned angles from ideal azimuth-elevation axes have been determined and corrected by a straightforward changing of the parameters' values in the general formula of the tracking algorithm to improve the tracking accuracy to 2.99 mrad, which falls below the encoder resolution limit of 4.13 mrad.
  5. Somchit N, Wong CW, Zuraini A, Ahmad Bustamam A, Hasiah AH, Khairi HM, et al.
    Drug Chem Toxicol, 2006;29(3):237-53.
    PMID: 16777703
    Itraconazole and fluconazole are potent wide spectrum antifungal drugs. Both of these drugs induce hepatotoxicity clinically. The mechanism underlying the hepatotoxicity is unknown. The purpose of this study was to investigate the role of phenobarbital (PB), an inducer of cytochrome P450 (CYP), and SKF 525A, an inhibitor of CYP, in the mechanism of hepatotoxicity induced by these two drugs in vivo. Rats were pretreated with PB (75 mg/kg for 4 days) prior to itraconazole or fluconazole dosing (20 and 200 mg/kg for 4 days). In the inhibition study, for 4 consecutive days, rats were pretreated with SKF 525A (50 mg/kg) or saline followed by itraconazole or fluconazole (20 and 200 mg/kg) Dose-dependent increases in plasma alanine aminotransferase (ALT), gamma-glutamyl transferase (gamma-GT), and alkaline phosphatase (ALP) activities and in liver weight were detected in rats receiving itraconazole treatment. Interestingly, pretreatment with PB prior to itraconazole reduced the ALT and gamma-GT activities and the liver weight of rats. No changes were observed in rats treated with fluconazole. Pretreatment with SKF 525A induced more severe hepatotoxicity for both itraconazole and fluconazole. CYP 3A activity was inhibited dose-dependently by itraconazole treatment. Itraconazole had no effects on the activity of CYP 1A and 2E. Fluconazole potently inhibited all three isoenzymes of CYP. PB plays a role in hepatoprotection to itraconazole-induced but not fluconazole-induced hepatotoxicity. SKF 525A enhanced the hepatotoxicity of both antifungal drugs in vivo. Therefore, it can be concluded that inhibition of CYP may play a key role in the mechanism of hepatotoxicity induced by itraconazole and fluconazole.
  6. Lim WY, Cheng YW, Lian LB, Chan EWC, Wong CW
    J Food Sci Technol, 2021 Nov;58(11):4178-4184.
    PMID: 34538902 DOI: 10.1007/s13197-020-04886-5
    Undesired browning reaction catalyzed by polyphenol oxidase (PPO) has reduced the nutritional quality and customer acceptance of the products. The inhibitory effects of six coastal plants including Sonneratia alba, Rhizophora apiculata, Syzygium grande, Rhizophora mucronata, Hibiscus tiliaceus and Bruguiera gymnorhiza on PPO in banana, sweet potato and ginger were studied based on oxidation of pyrocatechol. Banana exhibited the highest PPO activity (141,600 U), followed by sweet potato (43,440 U) and ginger (26,880 U). Banana PPO was strongly inhibited by R. apiculata (70.87%) and sweet potato PPO was strongly inhibited by S. alba (82.00%). In general, most banana PPO was the most susceptible to inhibition with all inhibitors having inhibition higher than 60.00% at 0.5 mg/ml and ginger PPO was the least susceptible with all inhibitors showing less than 50.00% inhibition at 0.5 mg/ml. Coastal plant extracts are potentially to be developed as natural inhibitors for preventing enzymatic browning of fruits and vegetables.
  7. Pui LP, Karim R, Yusof YA, Wong CW, Ghazali HM
    Acta Sci Pol Technol Aliment, 2021 4 23;20(2):135-148.
    PMID: 33884852 DOI: 10.17306/J.AFS.0801
    BACKGROUND: 'Cempedak' (Artocarpus integer) is an aromatic fruit which is similar to jackfruit. Although it is rich in vitamin A and is consumed fresh, the fruit has a short shelf life. Hence, it can be converted through a spray-drying process, to form powder, which is more stable. Powder flow properties are important when considering storage, while its reconstitution characteristics are critical for the consumer to make juice from the product.

    METHODS: The parameters of spray-dried 'cempedak' fruit powder under study include inlet air temperature (140-180°C) and maltodextrin (DE 10) concentrations (5-15% w/w). Response surface methodology involving 14 runs was used to assess the effects of inlet temperature and maltodextrin on the powder flow properties and reconstitution properties of the spray-dried 'cempedak' powder.

    RESULTS: Out of the tested responses, only bulk density, change in cake height ratio, and water solubility index had a high coefficient of determination value. Inlet air temperature was found to be the main parameter to affect the bulk density, caking and water solubility index, when compared to maltodextrin concentration. By setting minimization of caking and maximization of water solubility index as the main determinants, the optimal parameters of 160°C inlet temperature and 15% (w/w) maltodextrin DE10 were generated, with a desirability of 0.697.

    CONCLUSIONS: The powder produced under optimal conditions (160°C and 15% w/w maltodextrin) had a low bulk density (480.01 kg/m3), low caking properties (0.17 change in cake height ratio), and a high solubility index (88.69). This indicates that the powder is stable to be stored (without caking) and will have good reconstitution when added to water.

  8. Lim CSS, Chan EWC, Wong CW
    Int J Biol Macromol, 2024 Feb;259(Pt 2):129303.
    PMID: 38216018 DOI: 10.1016/j.ijbiomac.2024.129303
    Cellulose nanocrystals (CNC) conventionally involve highly concentrated sulphuric acid, which typically resulted in the formation of undesirable by-products. Although less corrosive mineral acids have been explored as alternatives, high concentrations are still required. In this study, CNC was successfully isolated from Leucaena leucocephala wood using mild sulphuric acid with acetic acid as protic solvent, and it was further studied with the addition of Lewis acids in the form of multivalent transition metal salts as co-catalyst. Selected divalent and trivalent transition metal salts including (Cr(NO3)3, Fe(NO3)3, Co(NO3)2, and Ni(NO3)2) were investigated. The morphology, chemical structure, particle size, and physicochemical properties of the CNCs were determined. Controlled depolymerization of cellulose was observed using transmission electron microscopy (TEM). Rod-like morphology for all CNCs was obtained during the hydrolysis process with the smallest CNC particles found at an average length of 278.1 ± 35.1 nm and a diameter of 13.4 ± 3.0 nm. The results showed that higher valence state metal ions resulted in better cellulose hydrolysis efficiency. In addition, the use of transition metal salt as a co-catalyst improved production efficiency and minimised carbonization of CNC while maintaining desired crystallinity and thermal properties.
  9. Sthaneshwar P, Vethakkan SR, Wong CW
    Med J Malaysia, 2014 Aug;69(4):175-7.
    PMID: 25500845 MyJurnal
    INTRODUCTION: Glycohemoglobin (HbA1c) most accurately reflects the previous two to three months of glycaemic control. HbA1c should be measured regularly in all patients with diabetes, and values should be maintained below 7% to prevent the risk of chronic complications. Apart from the genetic variants of haemoglobins many other conditions also known to affect HbA1c measurements. In this study we evaluated the conditions that cause low HbA1c results.

    METHODS AND MATERIALS: The data was collected retrospectively HbA1c was measured in our laboratory by Biorad Variant II turbo 2.0. The method is based on chromatographic separation of HbA1c on a cation exchange cartridge. This method has been certified by National Glycohemoglobin Standardization Programme (NGSP). 58437 requests were received in a period of one year (January to December 2011). Medical records were reviewed to identify the conditions that might be associated with these low values.

    RESULTS: Among 58437 samples analysed, 53 patients had HbA1c levels < 4.0%. Fourteen patients had haemoglobinopathy. In 34 patients without Hb variants had conditions such as chronic liver disease, chronic kidney disease, haemolytic anaemia, pregnancy, and anaemia of chronic disease. Five non-pregnant individuals who were screened for diabetes mellitus had HbA1c levels < 4%.

    CONCLUSION: Our study underscores the importance of that both laboratories and the physicians should be aware of the factors that can influence the HbA1c results. The haematological status should be taken into consideration for proper interpretation of HbA1c results.
  10. Lin H, Ng AWR, Wong CW
    Food Sci Biotechnol, 2016;25(Suppl 1):91-96.
    PMID: 30263491 DOI: 10.1007/s10068-016-0103-x
    Purification and characterization of polyphenol oxidase (PPO) from Chinese parsley (Coriandrum sativum) were achieved. Crude PPO exhibited an enzyme activity of 1,952.24 EU/mL. PPO was partially purified up to 6.52x with a 10.89% yield using gel filtration chromatography. Maximal PPO activity was found at 35°C, pH 8.0 for 4-methylcatechol and at 40°C, pH 7.0 for catechol. PPO showed a higher affinity towards 4-methylcatechol, but a higher thermal stability when reacting with catechol. LCysteine was a better inhibitor than citric acid for reducing PPO activity at concentrations of 1 and 3mM in the presence of either substrate. Two 46 kDa isoenzymes were identified using SDS-PAGE. Isolation and characterization of Chinese parsley serves as a guideline for prediction of enzyme behavior leading to effective prevention of enzymatic browning during processing and storage, including inhibition and inactivation of PPO.
  11. Chai SC, Wong CW
    Med J Malaysia, 2005 Jul;60 Suppl C:59-65.
    PMID: 16381286
    This retrospective study aims to evaluate the effectiveness of the modified regime for rehabilitation of Zone II flexor tendon injuries in Sibu Hospital. From January to December 2003, 8 patients with 15 injured digits were treated by using the combined method of dynamic traction and passive mobilization. According to Strickland's criteria, 14 (93.3%) digits achieved good to excellent outcomes and only 1 (6.7%) was rated as poor. No occurrence of tendon rupture was noted. The overall grip strength of the injured hand was 50.1% of the uninjured hand at 3 months after the repair. Our results compare favorably with the other published studies. We believed that this modified regime is as effective as other established regimes and suitable to be adopted in our setting. Further study with larger sample group will be required to consolidate our findings.
  12. Wong CW, Tan HH
    J Food Sci Technol, 2017 Feb;54(2):564-571.
    PMID: 28242955 DOI: 10.1007/s13197-017-2501-3
    This paper presents the enzymatic liquefaction process for honey jackfruit optimized with Pectinex® Ultra SP-L and Celluclast® 1.5 L individually or in combinations at different concentrations (0-2.5% v/w) and incubation time (0-2.5 h). Treatment with combinations of enzymes showed a greater effect in the reduction of viscosity (83.9-98.8%) as compared to single enzyme treatment (64.8-87.3%). The best parameter for enzymatic liquefaction was obtained with 1.0% (v/w) Pectinex® Ultra SP-L and 0.5% (v/w) Celluclast® 1.5 L for 1.5 h. Spray drying process was carried out using different inlet temperatures (140-180 °C) and maltodextrin concentrations (10-30% w/w). Results indicated that the spray-dried honey jackfruit powder produced at 160 °C with 30% w/w maltodextrin gave the highest product yield (66.90%) with good powder qualities in terms of water activity, solubility, moisture content, hygroscopicity, color and bulk density. The spray-dried honey jackfruit powder could potentially be incorporated into various food products.
  13. Lim WY, Wong CW
    J Food Sci Technol, 2018 Aug;55(8):3001-3007.
    PMID: 30065409 DOI: 10.1007/s13197-018-3218-7
    Food browning is undesirable as it causes deterioration in food quality and appearance. This phenomenon was related to polyphenol oxidase (PPO), which catalyzes conversion of phenolic compounds into o-quinones. The present work evaluated the use of chemical and natural anti-browning agents to prevent the browning of ginger PPO. Sodium metabisulfite (5 mM) is a better chemical inhibitor compared to l-cysteine and sodium chloride as 55.00% of ginger PPO inhibition was achieved. The percentage of inhibition increased as the concentration of anti-browning agents increases. The addition of heated onion, chili pepper and pineapple extracts exhibited a stronger inhibitory effect on ginger PPO than unheated extracts. Heated chili pepper extract was the best natural inhibitor found in this study and it inhibited the ginger PPO (47.97%) mixed-competitively. Natural anti-browning agents have potential to be used to control the browning of ginger as well as other vegetables and fruits.
Related Terms
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links