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Fulltext Neutron-activated biodegradable samarium-153 acetylacetonate-poly-L-lactic acid microspheres for intraarterial radioembolization of hepatic tumors

Wong YH, Tan HY, Kasbollah A, Abdullah BJJ, Acharya RU, Yeong CH

World J Exp Med, 2020 Mar 30;10(2):10-25.
PMID: 32266125 DOI: 10.5493/wjem.v10.i2.10

BACKGROUND: Liver cancer is the 6th most common cancer in the world and the 4th most common death from cancer worldwide. Hepatic radioembolization is a minimally invasive treatment involving intraarterial administration of radioembolic microspheres.
AIM: To develop a neutron-activated, biodegradable and theranostics samarium-153 acetylacetonate (153SmAcAc)-poly-L-lactic acid (PLLA) microsphere for intraarterial radioembolization of hepatic tumors.
METHODS: Microspheres with different concentrations of 152SmAcAc (i.e., 100%, 150%, 175% and 200% w/w) were prepared by solvent evaporation method. The microspheres were then activated using a nuclear reactor in a neutron flux of 2 × 1012 n/cm2/s1, converting 152Sm to Samarium-153 (153Sm) via152Sm (n, γ) 153Sm reaction. The SmAcAc-PLLA microspheres before and after neutron activation were characterized using scanning electron microscope, energy dispersive X-ray spectroscopy, particle size analysis, Fourier transform infrared spectroscopy, thermo-gravimetric analysis and gamma spectroscopy. The in-vitro radiolabeling efficiency was also tested in both 0.9% sodium chloride solution and human blood plasma over a duration of 550 h.
RESULTS: The SmAcAc-PLLA microspheres with different SmAcAc contents remained spherical before and after neutron activation. The mean diameter of the microspheres was about 35 µm. Specific activity achieved for 153SmAcAc-PLLA microspheres with 100%, 150%, 175% and 200% (w/w) SmAcAc after 3 h neutron activation were 1.7 ± 0.05, 2.5 ± 0.05, 2.7 ± 0.07, and 2.8 ± 0.09 GBq/g, respectively. The activity of per microspheres were determined as 48.36 ± 1.33, 74.10 ± 1.65, 97.87 ± 2.48, and 109.83 ± 3.71 Bq for 153SmAcAc-PLLA microspheres with 100%, 150%, 175% and 200% (w/w) SmAcAc. The energy dispersive X-ray and gamma spectrometry showed that no elemental and radioactive impurities present in the microspheres after neutron activation. Retention efficiency of 153Sm in the SmAcAc-PLLA microspheres was excellent (approximately 99%) in both 0.9% sodium chloride solution and human blood plasma over a duration of 550 h.
CONCLUSION: The 153SmAcAc-PLLA microsphere is potentially useful for hepatic radioembolization due to their biodegradability, favorable physicochemical characteristics and excellent radiolabeling efficiency. The synthesis of the formulation does not involve ionizing radiation and hence reducing the complication and cost of production.
Fulltext Binary solvent extraction system and extraction time effects on phenolic antioxidants from kenaf seeds (Hibiscus cannabinus L.) extracted by a pulsed ultrasonic-assisted extraction

Wong YH, Lau HW, Tan CP, Long K, Nyam KL

ScientificWorldJournal, 2014;2014:789346.
PMID: 24592184 DOI: 10.1155/2014/789346

The aim of this study was to determine the best parameter for extracting phenolic-enriched kenaf (Hibiscus cannabinus L.) seeds by a pulsed ultrasonic-assisted extraction. The antioxidant activities of ultrasonic-assisted kenaf seed extracts (KSE) were determined by a 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity assay, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging assay, β -carotene bleaching inhibition assay, and ferric reducing antioxidant power (FRAP) assay. Total phenolic content (TPC) and total flavonoid content (TFC) evaluations were carried out to determine the phenolic and flavonoid contents in KSE. The KSE from the best extraction parameter was then subjected to high performance liquid chromatography (HPLC) to quantify the phenolic compounds. The optimised extraction condition employed 80% ethanol for 15 min, with the highest values determined for the DPPH, ABTS, and FRAP assay. KSE contained mainly tannic acid (2302.20 mg/100 g extract) and sinapic acid (1198.22 mg/100 g extract), which can be used as alternative antioxidants in the food industry.
Fulltext Honey-induced protein stabilization as studied by fluorescein isothiocyanate fluorescence

Wong YH, Abdul Kadir H, Tayyab S

ScientificWorldJournal, 2013;2013:981902.
PMID: 24222758 DOI: 10.1155/2013/981902

Protein stabilizing potential of honey was studied on a model protein, bovine serum albumin (BSA), using extrinsic fluorescence of fluorescein isothiocyanate (FITC) as the probe. BSA was labelled with FITC using chemical coupling, and urea and thermal denaturation studies were performed on FITC-labelled BSA (FITC-BSA) both in the absence and presence of 10% and 20% (w/v) honey using FITC fluorescence at 522 nm upon excitation at 495 nm. There was an increase in the FITC fluorescence intensity upon increasing urea concentration or temperature, suggesting protein denaturation. The results from urea and thermal denaturation studies showed increased stability of protein in the presence of honey as reflected from the shift in the transition curve along with the start point and the midpoint of the transition towards higher urea concentration/temperature. Furthermore, the increase in ΔG D (H2O) and ΔG D (25°C) in presence of honey also suggested protein stabilization.
Conjugal transfer of multiple antibiotic resistance from hospital isolates of Klebsiella to Escherichia coli

Koh CL, Lim ME, Wong YH

Southeast Asian J. Trop. Med. Public Health, 1983 Sep;14(3):336-40.
PMID: 6362015

Six independent isolates of Klebsiella from hospital environmental sources in Malaysia were found to be resistant to at least ampicillin, carbenicillin, cefoperazone, chloramphenicol, gentamicin and tetracycline. On the basis of their antibiograms, they were divided into four antibiogroups. They transferred all or part of their multiple antibiotic resistance traits to E. coli by conjugation. The results suggest that these Klebsiella strains harbour self-transmissible R plasmids. The significance of these findings are discussed.
Fulltext Bacteraemic infections in a neonatal intensive care unit--a nine-month survey

Lim NL, Wong YH, Boo NY, Kasim MS, Chor CY

Med J Malaysia, 1995 Mar;50(1):59-63.
PMID: 7752978

A survey was conducted to determine the rate, outcome, and culture and sensitivity patterns of bacteraemic infections in a large Neonatal Intensive Care Unit (NICU). Over a nine-month period, 136 episodes of infection occurred in 132 (6.9%) out of 1926 admissions. Early onset infection accounted for 35 episodes (25.7%) and was associated with a higher mortality rate compared to late onset infection (45.7% vs 23.8%, p < 0.02). Very low birthweight (VLBW) infants had significantly higher rates of infection (19.4% vs 5.3%, p < 0.001) and mortality (45.2% vs 23.3%, p < 0.02) compared to bigger babies. Gram negative bacilli accounted for 25 early and 90 late isolates while gram positive organisms accounted for 10 early and 16 late isolates. The two main organisms (Acinetobacter and Klebsiella) showed a 69.0 to 85.3% resistance to aminoglycosides and 3rd generation cephalosporins. Ten of 13 isolates of Staphylococcus epidermidis and 3 of 4 Staphylococcus aureus were methicillin resistant. Multiply resistant infections were a major problem in this NICU and efforts to eradicate them needed to be intensified.
Fulltext A one year community-based study on the incidence of diarrhoea and rotavirus infection in urban and suburban Malaysian children

Yap KL, Yasmin AM, Wong YH, Ooi YE, Tan SC, Jegathesan M, et al.

Med J Malaysia, 1992 Dec;47(4):303-8.
PMID: 1303484

A 1 year longitudinal study of 156 Malaysian children from urban and suburban areas in the Klang Valley revealed that the incidence rate of diarrhoea was 23.6 per 100 person-year with abnormal faeces reported on 0.26% of the total days of observation. Diarrhoea cases were detected in children from all socioeconomic classes. Rotavirus was isolated from 12% of the diarrheic children and asymptomatic rotavirus infection occurred in 3.2% of the children. All rotaviruses isolated were group A rotaviruses with long electrophoretypic pattern.
Fulltext Methicillin-resistant Staphylococcus aureus (mrsa) in a Malaysian hospital

Cheong I, Tan SC, Wong YH, Zainudin BM, Rahman MZ

Med J Malaysia, 1994 Mar;49(1):24-8.
PMID: 8057986

Between August 1990 to November 1991, 905 of 2583 (35.4%) isolates of Staphylococcus aureus were found to be methicillin-resistant in a general hospital in Malaysia. A detailed study of 539 of these isolates showed a high prevalence of methicillin resistant Staphylococcus aureus (MRSA) in the surgical/orthopaedic wards, paediatric wards and the special care unit. The yield of MRSA was highest from wounds/ulcers/skin swabs accounting for 64.2 per cent followed by 6.9 per cent in blood cultures. Vancomycin remains the drug of choice with no resistance detected. The resistance to ciprofloxacin was 6.7 per cent, rifampicin 4.5 per cent and fusidic acid 2.0 per cent. Most isolates were resistant to aminoglycosides. In view of the high prevalence of MRSA in this hospital, the authorities must introduce more effective measures to control its spread as a nosocomial pathogen. Otherwise it may seriously disrupt the efficient delivery of health care services in the country.
Fulltext 5-Fluorocytosine resistance in clinical isolates of Cryptococcus neoformans

Chin CS, Cheong YM, Wong YH

Med J Malaysia, 1989 Sep;44(3):194-8.
PMID: 2696871

Thirty six clinical isolates of Cryptococcus neoformans were tested for their susceptibility to 5-fluorocytosine and amphotericin B by the determination of minimum inhibitory concentrations and minimum fungicidal concentrations. 22.2% of the isolates were resistant to 5-fluorocytosine and 36.1% indicated 5-fluorocytosine tolerance. All strains were sensitive to amphotericin B.
Fulltext The stethoscope and the transfer of bacteria in the neonatal nursery

Boo NY, Wong YH, Khoo AK

Med J Malaysia, 1989 Mar;44(1):87-8.
PMID: 2696869
Fulltext Campylobacter jejuni as a cause of diarrhoea in Kuala Lumpur, Malaysia

Lim YS, Jegathesan M, Wong YH

Med J Malaysia, 1984 Dec;39(4):285-8.
PMID: 6544934

The incidence of Campylobacter jejuni in patients with and without diarrhoea was studied in Kuala Lumpur, Malaysia. C. jejuni was recovered from 3.8% and 4.3% of diarrhoeal stools of children and adults, respectively. From the patients without diarrhoea, the relative isolation rates for children and adults were 2.6% and 0%, respectively. Dual infections occurred in two children, with Salmonella and enteropathogenic Escherichia coli being the other enteric pathogen in each case. Cary-Blair medium was found to be an effective transport medium in recovering C. jejuni. Campylobacter enteritis occurred in patients of various age groups, indicating that this organism should be sought routinely by diagnostic laboratories in faecal specimens from patients with diarrhoea.
Fulltext Pattern of neonatal septicemia in a Malaysian maternity hospital

Boo NY, Wong YH, Lim VK

Med J Malaysia, 1989 Sep;44(3):189-93.
PMID: 2626133

Over a 12 months period, out of 25,411 livebirths, 155 neonates (6.1 per 1000 livebirths) had proven septicemia by blood culture. The mortality rate was 26.5%. Septicemia was more common among the very low birthweight and preterm neonates of gestation of 30 weeks or less. 45.8% of the septicemia occurred during the first 48 hours of life. Staphylococcus epidermidis was the most common causative organism. However, mortality was highest among neonates who acquired multiresistant nosocomial infection during the later part of neonatal life.
Fulltext Plasmid-mediated transferable chloramphenicol and tetracycline resistance in Salmonella typhi (Vi phage type 25) isolated in Peninsular Malaysia

Koh CL, Lim ME, Wong YH

Med J Malaysia, 1983 Dec;38(4):320-4.
PMID: 6599991

A clinical isolate of Salmonella typhi (Vi phage type 25), resistant to chloramphenicol, streptomycin and tetracycline, was examined for the presence of R plasmids. Results from conjugation, agarose gel electrophoresis and transformation experiments indicated that it harboured a single large self-transmissible R plasmid which coded for both the chloramphenicol and tetracycline resistance traits.
The first isolate of Tatumella ptyseos in Malaysia

Tan SC, Wong YH, Jegathesan M, Chang SM

Malays J Pathol, 1989 Aug;11:25-7.
PMID: 2632996

Tatumella ptyseos, the type species for the genus Tatumella, is a newly established member of the Family Enterobacteriaceae. It is a Gram-negative, oxidase negative, fermentative rod that grows on Mac Conkey agar. This first isolate was obtained from the blood culture of a neonate having neonatal jaundice with presumed sepsis. The organism was in vitro sensitive to Gentamicin, Chloramphenicol, Cotrimoxazole and Ampicillin. The patient was treated with Ampicillin and Gentamicin and recovered uneventfully.
Concomitant cerebral and breast cryptococcosis

Arumugasamy N, Chin CS, Wong YH, Chew PH

Aust N Z J Surg, 1985 Oct;55(5):517-8.
PMID: 3868419

A patient with a solitary intracranial cryptococcoma of the occipital lobe of the brain and a concomitant granuloma of similar aetiology in the breast is reported. Despite resistance of the causative fungus to 5-fluorocytosine in vitro, the patient responded well to radical excisional surgery and therapy with 5-fluorocytosine.
Rapid assessment of total MCPD esters in palm-based cooking oil using ATR-FTIR application and chemometric analysis

Goh KM, Maulidiani M, Rudiyanto R, Wong YH, Ang MY, Yew WM, et al.

Talanta, 2019 Jun 01;198:215-223.
PMID: 30876552 DOI: 10.1016/j.talanta.2019.01.111

The technique of Fourier transform infrared spectroscopy is widely used to generate spectral data for use in the detection of food contaminants. Monochloropropanediol (MCPD) is a refining process-induced contaminant that is found in palm-based fats and oils. In this study, a chemometric approach was used to evaluate the relationship between the FTIR spectra and the total MCPD content of a palm-based cooking oil. A total of 156 samples were used to develop partial least squares regression (PLSR), artificial neural network (nnet), average artificial neural network (avNNET), random forest (RF) and cubist models. In addition, a consensus approach was used to generate fusion result consisted from all the model mentioned above. All the models were evaluated based on validation performed using training and testing datasets. In addition, the box plot of coefficient of determination (R2), root mean square error (RMSE), slopes and intercepts by 100 times randomization was also compared. Evaluation of performance based on the testing R2 and RMSE suggested that the cubist model predicted total MCPD content with the highest accuracy, followed by the RF, avNNET, nnet and PLSR models. The overfitting tendency was assessed based on differences in R2 and RMSE in the training and testing calibrations. The observations showed that the cubist and avNNET models possessed a certain degree of overfitting. However, the accuracy of these models in predicting the total MCPD content was high. Results of the consensus model showed that it slightly improved the accuracy of prediction as well as significantly reduced its uncertainty. The important variables derived from the cubist and RF models suggested that the wavenumbers corresponding to the MCPDs originated from the -CH=CH2 or CH=CH (990-900 cm-1) and C-Cl stretch (800-700 cm-1) regions of the FTIR spectrum data. In short, chemometrics in combination with FTIR analysis especially for the consensus model represent a potential and flexible technique for estimating the total MCPD content of refined vegetable oils.
Fulltext In-situ study of electrochemical migration of tin in the presence of bromide ion

Lee EL, Haseeb ASMA, Basirun WJ, Wong YH, Sabri MFM, Low BY

Sci Rep, 2021 Aug 03;11(1):15768.
PMID: 34344974 DOI: 10.1038/s41598-021-95276-0

The miniaturization of electronic devices and the consequent decrease in the distance between conductive lines have increased the risk of short circuit failure due to electrochemical migration (ECM). The presence of ionic contaminants affects the ECM process. This work systematically investigates the ECM of tin (Sn) in the presence of bromide ions (Br-) in the range of 10-6 M to 1.0 M. Water drop test (WDT) was conducted in the two-probe semiconductor characterization system under an optical microscope as an in-situ observation. Polarization test was carried out to study the correlation between the corrosion properties of Sn and its ECM behaviour. The products of ECM were characterized by scanning electron microscope coupled with an energy dispersive X-rays spectrometer (SEM/EDX) and X-ray photoelectron spectrometer (XPS). The results confirm that the rate of anodic dissolution of Sn monotonously increases with the Br- concentration. However, the probability of ECM failure follows a normal distribution initially, but later increases with the Br- concentration. The main products of the ECM reactions are identified as Sn dendrites and tin hydroxide precipitates. The mechanisms of the ECM process of Sn in the presence of Br- are also suggested.
Fulltext Monitoring of heat-induced carcinogenic compounds (3-monochloropropane-1,2-diol esters and glycidyl esters) in fries

Wong YH, Goh KM, Nyam KL, Cheong LZ, Wang Y, Nehdi IA, et al.

Sci Rep, 2020 09 15;10(1):15110.
PMID: 32934328 DOI: 10.1038/s41598-020-72118-z

3-Monochloropropane-1,2-diol (3-MCPD) esters and glycidyl esters (GE) are heat-induced contaminants which form during oil refining process, particularly at the high temperature deodorization stage. It is worth to investigate the content of 3-MCPD and GE in fries which also involved high temperature. The content of 3-MCPD esters and GE were monitored in fries. The factors that been chosen were temperature and duration of frying, and different concentration of salt (NaCl). The results in our study showed that the effect was in the order of concentration of sodium chloride
Effects of educational interventions on the smoking cessation service provided by community pharmacists: A systematic review

Appalasamy JR, Selvaraj A, Wong YH, Dujaili JA, Kow CS

Res Social Adm Pharm, 2022 Jan 31.
PMID: 35168890 DOI: 10.1016/j.sapharm.2022.01.008

OBJECTIVE: This systematic review aimed to evaluate the effectiveness of educational interventions on the smoking cessation service provided by community pharmacists.
METHODS: A systematic literature search was performed in May-July 2021, in electronic databases, which included PubMed (MEDLINE), Embase, and Web of Science. Studies were included in this systematic review if they were original articles published in English language from 2010 to 2021 and evaluated the effect of any types of educational interventions intended to improve the ability of community pharmacists to provide smoking cessation services.
RESULTS: In total, 12 studies were included for this systematic review. The effectiveness of the educational interventions across the included studies was measured using a range of outcomes, which can be broadly categorized into 3 categories, namely changes in pharmacists' self-efficacy, knowledge, and attitude toward providing smoking cessation service, changes in pharmacists' smoking cessation practices, and changes in the effectiveness of community pharmacy based smoking cessation services. Included studies reported that educational interventions can improve pharmacists' self-efficacy, knowledge, and attitude toward smoking cessation, as well as pharmacists' smoking cessation practices. Though the evidence is limited, improvement in the effectiveness of community pharmacy based smoking cessation services has also been observed.
CONCLUSION: Any form educational interventions can positively impact improve community pharmacists' self-efficacy, knowledge, and attitude toward smoking cessation, as well as pharmacists' smoking cessation practices, but it is currently uncertain whether these outcomes are able to translate into higher effectiveness of the community pharmacy based smoking cessation services.
Quantitative and qualitative comparison of low- and high-cost 3D-printed heart models

Lau I, Wong YH, Yeong CH, Abdul Aziz YF, Md Sari NA, Hashim SA, et al.

Quant Imaging Med Surg, 2019 Jan;9(1):107-114.
PMID: 30788252 DOI: 10.21037/qims.2019.01.02

Current visualization techniques of complex congenital heart disease (CHD) are unable to provide comprehensive visualization of the anomalous cardiac anatomy as the medical datasets can essentially only be viewed from a flat, two-dimensional (2D) screen. Three-dimensional (3D) printing has therefore been used to replicate patient-specific hearts in 3D views based on medical imaging datasets. This technique has been shown to have a positive impact on the preoperative planning of corrective surgery, patient-doctor communication, and the learning experience of medical students. However, 3D printing is often costly, and this impedes the routine application of this technology in clinical practice. This technical note aims to investigate whether reducing 3D printing costs can have any impact on the clinical value of the 3D-printed heart models. Low-cost and a high-cost 3D-printed models based on a selected case of CHD were generated with materials of differing cost. Quantitative assessment of dimensional accuracy of the cardiac anatomy and pathology was compared between the 3D-printed models and the original cardiac computed tomography (CT) images with excellent correlation (r=0.99). Qualitative evaluation of model usefulness showed no difference between the two models in medical applications.
Fulltext Development of patient-specific 3D-printed breast phantom using silicone and peanut oils for magnetic resonance imaging

Sindi R, Wong YH, Yeong CH, Sun Z

Quant Imaging Med Surg, 2020 Jun;10(6):1237-1248.
PMID: 32550133 DOI: 10.21037/qims-20-251

Background: Despite increasing reports of 3D printing in medical applications, the use of 3D printing in breast imaging is limited, thus, personalized 3D-printed breast model could be a novel approach to overcome current limitations in utilizing breast magnetic resonance imaging (MRI) for quantitative assessment of breast density. The aim of this study is to develop a patient-specific 3D-printed breast phantom and to identify the most appropriate materials for simulating the MR imaging characteristics of fibroglandular and adipose tissues.
Methods: A patient-specific 3D-printed breast model was generated using 3D-printing techniques for the construction of the hollow skin and fibroglandular region shells. Then, the T1 relaxation times of the five selected materials (agarose gel, silicone rubber with/without fish oil, silicone oil, and peanut oil) were measured on a 3T MRI system to determine the appropriate ones to represent the MR imaging characteristics of fibroglandular and adipose tissues. Results were then compared to the reference values of T1 relaxation times of the corresponding tissues: 1,324.42±167.63 and 449.27±26.09 ms, respectively. Finally, the materials that matched the T1 relaxation times of the respective tissues were used to fill the 3D-printed hollow breast shells.
Results: The silicone and peanut oils were found to closely resemble the T1 relaxation times and imaging characteristics of these two tissues, which are 1,515.8±105.5 and 405.4±15.1 ms, respectively. The agarose gel with different concentrations, ranging from 0.5 to 2.5 wt%, was found to have the longest T1 relaxation times.
Conclusions: A patient-specific 3D-printed breast phantom was successfully designed and constructed using silicone and peanut oils to simulate the MR imaging characteristics of fibroglandular and adipose tissues. The phantom can be used to investigate different MR breast imaging protocols for the quantitative assessment of breast density.

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