Displaying publications 1 - 20 of 72 in total

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  1. Chang CT, Ang JY, Wong JM, Tan SS, Chin SK, Lim AB, et al.
    Med J Malaysia, 2020 05;75(3):286-291.
    PMID: 32467546
    AIM: This study is conducted to compare the pharmacokinetic profiles of two fixed dose combination of metformin/glibenclamide tablets (500mg/5 mg per tablet).

    MATERIALS AND METHODS: This is a single-center, single-dose, open-label, randomized, 2-treatment, 2-sequence and 2- period crossover study with a washout period of 7 days. All 28 adult male subjects were required to fast for at least 10 hours prior to drug administration and they were given access to water ad libitum during this period. Thirty minutes prior to dosing, all subjects were served with a standardized high-fat and high-calorie breakfast with a total calorie of 1000 kcal which was in accordance to the EMA Guideline on the Investigation of Bioequivalence. Subsequently, subjects were administered either the test or reference preparation with 240mL of plain water in the first trial period. During the second trial period, they received the alternate preparation. Plasma levels of glibenclamide and metformin were analysed separately using two different high performance liquid chromatography methods.

    RESULTS: The 90% confidence interval (CI) for the ratio of the AUC0-t, AUC0-∞, and Cmax of the test preparation over those of the reference preparation were 0.9693-1.0739, 0.9598- 1.0561 and 0.9220 - 1.0642 respectively. Throughout the study period, no serious drug reaction was observed. However, a total of 26 adverse events (AE)/side effects were reported, including 24 that were definitely related to the study drugs, namely giddiness (n=17), while diarrheoa (n=3), headache (n=2) and excessive hunger (n=2) were less commonly reported by the subjects.

    CONCLUSION: It can be concluded that the test preparation is bioequivalent to the reference preparation.

  2. Yap SP, Julianto T, Wong JW, Yuen KH
    J Chromatogr B Biomed Sci Appl, 1999 Dec 10;735(2):279-83.
    PMID: 10670741
    A simple high-performance liquid chromatographic method using fluorescence detection was developed for the determination of vitamin E especially delta-, gamma- and alpha-tocotrienols in human plasma. The method entailed direct injection of plasma sample after deproteinization using a 3:2 mixture of acetonitrile-tetrahydrofuran. The mobile phase comprised 0.5% (v/v) of distilled water in methanol. Analyses were run at a flow-rate of 1.5 ml/min with the detector operating at an excitation wavelength of 296 nm and emission wavelength of 330 nm. This method is specific and sensitive, with a quantification limit of approximately 40, 34 and 16 ng/ml for alpha-, gamma- and delta-tocotrienol, respectively. The mean absolute recovery values were about 98% while the within-day and between-day relative standard deviation and percent error values of the assay method were all less than 12.0% for alpha-, gamma- and delta-tocotrienol. The calibration curve was linear over a concentration range of 40-2500, 30-4000 and 16-1000 ng/ml for alpha-, gamma- and delta-tocotrienol, respectively. Application of the method in a bioavailability study for determination of the above compounds was also demonstrated.
  3. Wong JW, Yuen KH
    Int J Pharm, 2001 Oct 04;227(1-2):177-85.
    PMID: 11564552
    The bioavailability of beta- and gamma-cyclodextrin artemisinin complexes was evaluated in comparison with a normal commercially available preparation, Artemisinin 250. Twelve healthy male volunteers participated in the study conducted according to a three-way crossover design. The bioavailability was compared using the parameters, total area under the plasma level-time curve (AUC(0-infinity)), peak plasma concentration (C(max)), and time to reach peak plasma concentration (T(max)). A statistically significant difference was observed between the values of the complexes and Artemisinin 250 for the three parameters. However, no statistically significant difference was observed between the values of the beta- and gamma-cyclodextrin complexes. Moreover, the 90% confidence interval for the ratio of the AUC(0-infinity) values of the beta-cyclodextrin complex over those of Artemisinin 250 was estimated to be between 1.51-2.04, while that of C(max) was between 1.73-2.93. For the gamma-cyclodextrin complex, the respective intervals were 1.30-1.76 and 1.43-2.43. These findings indicated that the beta- and gamma-cyclodextrin complexes had a much higher rate and extent of bioavailability compared to Artemisinin 250. In addition, the absorption of artemisinin was observed to be poor and negligible when the preparations started to arrive in the colon. This could be attributed to poor dissolution of artemisinin in the semi-solid faecal matter in the lower part of the gastrointestinal tract.
  4. Wong JW, Yuen KH
    Drug Dev Ind Pharm, 2003 Oct;29(9):1035-44.
    PMID: 14606667
    The present study was conducted to investigate the inclusion complexation of artemisinin (ART) with natural cyclodextrins (CyD), namely alpha-, beta-, and gamma-CyDs with the aim of improving its solubility and dissolution rate. Complex formation in aqueous solution and solid state was studied by solubility analysis, dissolution, and thermal analysis. Solubility diagrams indicated that the complexation of ART and the three CyDs occurred at a molar ratio of 1:1, and showed a remarkable increase in ART solubility. Moreover, the thermodynamic parameters calculated by using the van't Hoff equation revealed that the complexation process was associated with negative enthalpy of formation and occurred spontaneously. The complexation capability of CyDs with ART increased in the order of alpha- < gamma- < beta-CyDs and could be ascribed to the structural compatibility between the molecular size of ART and the diameter of the CyD cavities. Dissolution profiles of the three complexes demonstrated an increased rate and extent of dissolution compared with those of their respective physical mixtures and a commercial preparation. In solid-state analysis, using differential scanning calorimetry, the gamma-CyD was capable of complexing the highest percentage of ART, followed by beta- and alpha-CyDs. The respective estimated percentage of ART complexed by the CyDs were 85%, 40%, and 12%.
  5. Yuen KH, Choy WP, Tan HY, Wong JW, Yap SP
    J Pharm Biomed Anal, 2001 Feb;24(4):715-9.
    PMID: 11272330
    A simple high-performance liquid chromatographic method was developed for the determination of omeprazole in human plasma. Omeprazole and the internal standard, chloramphenicol, were extracted from alkalinized plasma samples using dichloromethane. The mobile phase was 0.05 M Na2HPO4-ACN (65:35, v/v) adjusted to pH 6.5. Analysis was run at a flow rate of 1.0 ml/min at a detection wavelength of 302 nm. The method was specific and sensitive with a detection limit of 2.5 ng/ml at a signal-to-noise ratio of 4:1. The limit of quantification was set at 5 ng/ml. The calibration curve was linear over a concentration range of 5-1280 ng/ml. Mean recovery value of the extraction procedure was about 96%, while the within and between day coefficient of variation and percent error values of the assay method were all less than 14%.
  6. Wong JS, Ng KH, Wong SH
    J Clin Neurosci, 2004 Apr;11(3):254-8.
    PMID: 14975412
    This is a prospective study conducted from February 2000 to July 2002 in a single neurosurgeon neurosurgical service in the state of Sarawak, Malaysia. There were 66 cases of subarachnoid hemorrhage or intracranial aneurysm presenting to this hospital over the study period. Fifty cases had their aneurysms clipped. Eighty percent of our patients were operated within 48 h of presentation. Forty-four percent presented with poor WFNS grades of 4 and 5. We had a 20% operative mortality and 29% total management mortality. Twenty-nine (58%) of the operated cases had a favorable outcome with a mean follow-up of 32 weeks. Multiple aneurysms were less common. The diagnosis of aneuysmal subarachnoid hemorrhage and clipping of aneurysms have increased dramatically over the previous two and half years indicating an increased awareness of the diagnosis and treatment. This series supports the previously reported beliefs that the lower rate of aneurymal subarachnoid hemorrhage in developing countries is likely due to both underdiagnosis and undertreatment. Good results can be achieved in developing countries with early diagnosis and intensive management.
  7. Magosso E, Yuen KH, Choy WP, Ling SSN, Ng BH, Ur-Rahman N, et al.
    Med J Malaysia, 2004 Aug;59(3):352-6.
    PMID: 15727381
    The bioavailability of a generic diclofenac sodium sustained release tablet preparation (Zolterol, SR) was compared with the innovator product, Voltaren, SR. Twelve healthy adult male volunteers participated in the study, which was conducted according to a randomized, two-way crossover design with a wash out period of one week. The bioavailability of diclofenac was compared using the parameters area under the plasma concentration-time curve (AUC(0-infinity)), peak plasma concentration (Cmax) and time to reach peak plasma concentration (Tmax). No statistically significant difference was observed for both logarithmically transformed AUC(0-infinity), Cmax values and Tmax value of the two preparations.
  8. Yap SP, Yuen KH, Wong JW
    J Pharm Pharmacol, 2001 Jan;53(1):67-71.
    PMID: 11206194
    We have investigated the pharmacokinetics and bioavailability of alpha-, gamma- and delta-tocotrienols under fed and fasted conditions in eight healthy volunteers. The volunteers were administered a single oral dose of mixed tocotrienols (300 mg) under fed or fasted conditions. The bioavailability of tocotrienols under the two conditions was compared using the parameters peak plasma concentration (Cmax), time to reach peak plasma concentration (Tmax) and total area under the plasma concentration-time curve (AUC(o-infinity)). A statistically significant difference was observed between the fed and fasted logarithmic transformed values of Cmax (P < 0.01) and AUC(0-infinity) (P < 0.01) for all three tocotrienols. In addition, the 90% confidence intervals for the ratio of the logarithmic transformed AUC(0-infinity) values of alpha-, gamma- and delta-tocotrienols under the fed state over those of the fasted state were found to lie between 2.24-3.40, 2.05-4.09 and 1.59-3.81, respectively, while those of the Cmax were between 2.28-4.39, 2.31-5.87 and 1.52-4.05, respectively. However, no statistically significant difference was observed between the fed and fasted Tmax values of the three homologues. The mean apparent elimination half-life (t(1/2)) of alpha-, gamma- and delta-tocotrienols was estimated to be 4.4, 4.3 and 2.3 h, respectively, being between 4.5- to 8.7-fold shorter than that reported for alpha-tocopherol. No statistically significant difference was observed between the fed and fasted t(1/2) values. The mean apparent volume of distribution (Vd/f) values under the fed state were significantly smaller than those of the fasted state, which could be attributed to increased absorption of the tocotrienols in the fed state.
  9. Teh CL, Kuan YC, Wong JS
    Rheumatol Int, 2009 Aug;29(10):1243-5.
    PMID: 19373465 DOI: 10.1007/s00296-009-0938-z
    We performed a cross-sectional study of the demography, clinical and laboratory features of patients with systemic sclerosis patients followed up in our centre from 1984 to 2007. There were 23 cases with the majority of them (96%) being female. They have a mean age of 50.3 years and a mean disease duration of 6.02 (SD 5.82) years. Our patients comprised of multi-ethnic groups with predominantly Chinese (52%), Sarawak natives (35%) and Malays (13%). They have a mean lag time to diagnosis of 24.8 (SD 34.8) months. All the patients have sclerodermatous skin changes with 16(70%) having diffuse scleroderma and 7(30%) having limited scleroderma. The common clinical manifestations found in our patients were Raynaud's phenomenon (91%), sclerodactyly (65%), digital ulcers (52%) and pulmonary fibrosis (52%). There was low incidence of pulmonary hypertension (13%) and renal involvement (4%). The majority of our patients (67%) have positive ANA with 33% positive Scl-70. The majority received calcium channel blockers (87%), aspirin (48%) and low-dose prednisolone (48%). One patient developed adenocarcinoma of the lung on follow-up. This study demonstrated the rarity of systemic sclerosis in our centre with considerable lag time to diagnosis in our patients. Diffuse cutaneous systemic scleroderma is more common in our centre with rare pulmonary hypertension and renal involvement.
  10. Teh CL, Wong JS
    Clin Rheumatol, 2008 Nov;27(11):1437-40.
    PMID: 18773254 DOI: 10.1007/s10067-008-0945-6
    The aim of our study is to describe the pattern, clinical features, treatment regimes, and disease activity among the patients treated for rheumatoid arthritis (RA) in the Sarawak General Hospital. We performed a cross-sectional study of all patients with a diagnosis of RA who received treatment at the General Medical Clinic and the Rheumatology Clinic in Sarawak General Hospital over a 1-year period from 1st June 2006 to 31st May 2007. Demographic data, clinical features, and disease activity of all 154 patients were collected for statistical analysis. Rheumatoid arthritis afflicts all the major racial groups in Sarawak including the native population. Our patients have a mean disease duration of 5.4 years (SD 5.69) and a mean duration of delay in diagnosis RA and initiation of disease-modifying antirheumatic drug (DMARD) treatment of 42.9 months (SD 60.1). They have a low rate of interstitial lung disease (6.5%) and rheumatoid nodules (4.5%). Rheumatoid factor was positive in 65.5% of our patients. They have a mean Disease Activity Score (DAS) 28 score of 4.28 (SD 1.33). Only 12.5% of our patients are in remission with DAS 28 < 2.6 and 30.9% of our patients are having high disease activity with DAS 28 > 5.1. Despite the high usage of DMARDs in Sarawak (>80%), our patients have severe disease with high disease activity indices. This is most likely due to delay in diagnosis and initiating DMARDs in RA patients in Sarawak.

    Study site: General Medical Clinic and the Rheumatology Clinic in Sarawak General Hospital
  11. Wong EY, Chew PT, Chee CK, Wong JS
    Am J Ophthalmol, 1997 Dec;124(6):797-804.
    PMID: 9402826
    PURPOSE: To evaluate the effectiveness and safety of diode laser contact transscleral cyclophotocoagulation in Asian patients with refractory glaucoma by lower energy settings with an innovative probe featuring a glass ball tip that focused the laser beam onto the ciliary body.

    METHODS: This prospective clinical study included consecutive Asian patients with dark irides and confirmed for glaucoma. Only one eye of each patient was treated. Diode laser contact transscleral cyclophotocoagulation treatment was performed with the center of the probe placed 1.5 mm behind the limbus. About 30 pulses of 810-mm laser radiation (power, 1.8 to 2.0 W; duration, 0.3 to 0.5 second) were applied around the eye. Patients were examined at fixed postoperative intervals. Intraocular pressure levels and postoperative complications were recorded. The relation between patient and disease characteristics, total laser energy delivered, and intraocular pressure effects were analyzed.

    RESULTS: Thirty-three patients were studied, with a mean follow-up period of 9.4 months. An average 56% of patients showed a 30% or greater drop in intraocular pressure. About 38% of patients achieved sustained intraocular pressure lowering to below 22 mm Hg at 18 months. Complications were few and included transient hypotony and iritis.

    CONCLUSIONS: In Asian patients with refractory glaucoma or painful glaucomatous eyes with poor visual acuity (defined for this study as worse than 20/200), low-energy-setting diode laser contact transscleral cyclophotocoagulation by means of the glass ball probe is relatively effective and safe.

  12. Wong JS
    Med J Malaysia, 2005 Jun;60(2):146-50.
    PMID: 16114154 MyJurnal
    Diabetic nephropathy is now the number one cause of end stage renal failure in Malaysia. This places a huge burden on patients and the health care system especially in developing countries with limited health care resources, such as in Sarawak in East Malaysia. This study describes the prevalence of proteinuria/microalbuminuria in diabetic patients treated in Klinik Kesihatan Tanah Puteh. Early detection of proteinuria/microalbuminuria allows remedial measures to be taken to retard the progression of nephropathy. Forty-eight percent of the cases had proteinuria and microalbuminuria was found in 16%. Seventy-eight percent of cases with proteinuria were on treatment with angiotensin-converting-enzyme inhibitors or angiotensin-receptor blockers. Seventy-five percent of patients had hypertension but only 6% achieved the targeted BP of < 130/80 mmHg.
    Study site: Diabetic clinic of Klinik Kesihatan Tanah Puteh, Kuching, Sarawak, Malaysia
  13. Suhara S, Wong AS, Wong JO
    Br J Neurosurg, 2008 Apr;22(2):295-7.
    PMID: 18348031 DOI: 10.1080/02688690701687678
    A 27-year-old patient presented with severe headache and seizures about a month after the initial head trauma. Computed tomography (CT) brain scan revealed acute subdural bleed continuous into the interhemispheric region, with no subarachnoid haemorrhage. This was due to rupture of a traumatic pericallosal artery aneurysm. This represents a rare case of traumatic pericallosal artery aneurysm presenting with subdural haematoma without subarachnoid haemorrhage.
  14. Abdul Rahaman JA, Ker HB, Yusof M, Hanafi NS, Wong JL
    Malays Fam Physician, 2014;9(3):34-7.
    PMID: 26425303 MyJurnal
    Tuberculosis (TB) in Malaysia is rising due to multiple factors and issues related to its management are addressed in the updated evidence-based clinical practice guidelines. Screening for active TB should be considered in high risk groups. Light emitting diode-based fluorescence microscopy and nucleic acid amplification tests are recommended investigations. Health education and standardised 6-month daily antituberculosis (antiTB) regimen are among important elements for successful treatment. Latent TB infection screening should only be performed on high risk individuals. AntiTB regimen offered to HIV-positive adults should be the same as for HIV-negative adults and timing to initiate highly active antiretroviral therapy in patients with TB is based on CD4 count. All patients on antiTB treatment should be monitored to assess their response to treatment and to identify problems associated with it.
  15. Chong LA, Khalid F, Khoo TB, Teh SH, Kuan GL, Aina Mariana AM, et al.
    Med J Malaysia, 2017 02;72(1):32-36.
    PMID: 28255137 MyJurnal
    INTRODUCTION: Awareness for paediatric palliative care has resulted in the impetus for paediatrician-led palliative care services across Malaysia. However, there is paucity of local data on patients receiving hospital-based paediatric palliative care. We aim to review the clinical spectrum of patients referred to these services.

    METHODS: An observational study of children aged between 0-18 years receiving palliative care at 13 hospitals between 1st January and 31st December 2014 was carried out.

    RESULTS: There were 315 patients analysed, 90 (28.6%) and 46 (14.6%) were neonates and adolescents respectively. The main ICD-10 diagnostic categories for all patients were identified to be 'Congenital malformations, deformations and chromosomal abnormalities' 117 (37.1%), 'Diseases of nervous system' 76 (24.1%) and 'Neoplasms' 60 (19.0%). At referral 156 (50%) patients had holistic needs assessments. Patients with 'Diseases of nervous system' were assessed to have significantly more physical needs than the other two diagnostic categories. Majority of patients who knew of their diagnosis and prognosis were those with malignancy. Over a fifth of referrals were at their terminal admission. Of 144 who died, 111 (77.1%) had advanced care plans. There was bereavement follow-up in 98 (68.1%) patients.

    CONCLUSION: Patients referred for palliative care have varied diagnoses and needs. To ensure all paediatricians are competent to deliver quality care to all children, further education and training initiatives is imperative.

  16. Jong WL, Ung NM, Vannyat A, Rosenfeld AB, Wong JHD
    Phys Med, 2017 Oct;42:39-46.
    PMID: 29173919 DOI: 10.1016/j.ejmp.2017.08.011
    Challenges in treating lung tumours are related to the respiratory-induced tumour motion and the accuracy of dose calculation in charged particle disequilibrium condition. The dosimetric characteristics near the interface of lung and Perspex media in a moving phantom during respiratory-gated and non-gated radiotherapy were investigated using Gafchromic EBT2 and the MOSkin detector. The MOSkin detectors showed good agreement with the EBT2 films during static and gated radiotherapy. In static radiotherapy, the penumbral widths were found to be 3.66mm and 7.22mm in Perspex and lung media, respectively. In non-gated (moving) radiotherapy with 40mm respiratory amplitude, dose smearing effect was observed and the penumbral widths were increased to 28.81mm and 26.40mm, respectively. This has been reduced to 6.85mm and 9.81mm, respectively, in gated radiotherapy with 25% gating window. There were still some dose discrepancies as compared to static radiotherapy due to the residual motion. This should be taken into account in the margin generation for the target tumour.
  17. Ng Kh, Wong J
    Biomed Imaging Interv J, 2008 Apr;4(2):e21.
    PMID: 21614324 DOI: 10.2349/biij.4.2.21
    Informal discussion started in 1996 and the South East Asian Federation of Organizations for Medical Physics (SEAFOMP) was officially accepted as a regional chapter of the IOMP at the Chicago World Congress in 2000 with five member countries, namely Indonesia, Malaysia, Philippines, Singapore and Thailand. Professor Kwan-Hoong Ng served as the founding president until 2006. Brunei (2002) and Vietnam (2005) joined subsequently. We are very grateful to the founding members of SEAFOMP: Anchali Krisanachinda, Kwan-Hoong Ng, Agnette Peralta, Ratana Pirabul, Djarwani S Soejoko and Toh-Jui Wong.The objectives of SEAFOMP are to promote (i) co-operation and communication between medical physics organizations in the region; (ii) medical physics and related activities in the region; (iii) the advancement in status and standard of practice of the medical physics profession; (iv) to organize and/or sponsor international and regional conferences, meetings or courses; (v) to collaborate or affiliate with other scientific organizations.SEAFOMP has been organizing a series of congresses to promote scientific exchange and mutual support. The South East Asian Congress of Medical Physics (SEACOMP) series was held respectively in Kuala Lumpur (2001), Bangkok (2003), Kuala Lumpur (2004) and Jakarta (2006). The respective congress themes indicated the emphasis and status of development. The number of participants (countries in parentheses) was encouraging: 110 (17), 150 (16), 220 (23) and 126 (7).In honour of the late Professor John Cameron, an eponymous lecture was established. The inaugural John Cameron Lecture was delivered by Professor Willi Kalender in 2004. His lecture was titled "Recent Developments in Volume CT Scanning".
  18. Chaw L, Koh WC, Jamaludin SA, Naing L, Alikhan MF, Wong J
    Emerg Infect Dis, 2020 Nov;26(11):2598-2606.
    PMID: 33035448 DOI: 10.3201/eid2611.202263
    We report the transmission dynamics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) across different settings in Brunei. An initial cluster of SARS-CoV-2 cases arose from 19 persons who had attended the Tablighi Jama'at gathering in Malaysia, resulting in 52 locally transmitted cases. The highest nonprimary attack rates (14.8%) were observed from a subsequent religious gathering in Brunei and in households of attendees (10.6%). Household attack rates from symptomatic case-patients were higher (14.4%) than from asymptomatic (4.4%) or presymptomatic (6.1%) case-patients. Workplace and social settings had attack rates of <1%. Our analyses highlight that transmission of SARS-CoV-2 varies depending on environmental, behavioral, and host factors. We identify red flags for potential superspreading events, specifically densely populated gatherings with prolonged exposure in enclosed settings, persons with recent travel history to areas with active SARS-CoV-2 infections, and group behaviors. We propose differentiated testing strategies to account for differing transmission risk.
  19. Wong J, Chin Liew S, Wong E
    Appl Opt, 2020 Nov 01;59(31):9690-9697.
    PMID: 33175805 DOI: 10.1364/AO.405227
    The ECO-BB (Sea Bird Scientific) is a popular instrument used by water optics researchers to measure the backscattering coefficient of waters in the visible to near-infrared wavelengths. The ECO-BB is calibrated by default for oceanic waters where the backscattering coefficient is typically low. In inland and coastal waters however, there is a tendency for the ECO-BB to reach saturation due to the high number of suspended particles. In the paper, a simple method is presented to extend the range of the ECO-BB instrument in such waters using a nephelometric turbidimeter. The method was first tested on powdered calcium carbonate in pure freshwater, followed by collected water samples from the Singapore Straits and the Lupar River in Sarawak. All three tests confirm the correlation between the ECO-BB and turbidimeter and show that the turbidimeter is a good proxy for backscattering coefficient measurements in turbid waters.
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