Displaying publications 1 - 20 of 72 in total

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  1. 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
  2. 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".
  3. Wong JS, Rahimah N
    Med J Malaysia, 2004 Aug;59(3):411-7.
    PMID: 15727390 MyJurnal
    Achieving glycaemic goals in diabetics has always been a problem, especially in a developing country with inadequate facilities such as in Sarawak in Malaysia. There are no reported studies on the control of diabetes mellitus in a diabetic clinic in the primary health care setting in Sarawak. This paper describes the profile of 1031 patients treated in Klinik Kesihatan Tanah Puteh Health Centre. The mean age was 59 years, the mean BMI 27 kg/m2. There was a female preponderance and mainly type-2 diabetes. Mean HbA1c was 7.4%. Glycaemic control was optimal in 28% (HbA1c <6.5%), fair in 34% (HbA1c 6.5-7.5%) and poor in 38% (HbA1c >7.5%). Reasonable glycaemic control can be achieved in the primary health care setting in Sarawak.
    Study site: Klinik Kesihatan Tanah Puteh, Sarawak, Malaysia
  4. Tan F, Chan G, Wong JS, Rozario F
    Med J Malaysia, 2008 Aug;63(3):224-8.
    PMID: 19248695 MyJurnal
    We audited the standard of care provided to 200 consecutive type 2 diabetic patients attending our hospital general medical clinic. Data on diabetes related processes and outcome measures were collected. Annual testing rates (blood pressure 100%, fasting lipid profile 91.8%, HbA1c 69%) were higher compared to complications screening rates (Eye 69%, albuminuria 51%, foot 22.4%). Lifestyle intervention was lacking with BMI documented in 38.3% of patients and smoking history in 46%. Fifty percent and 41% of patients with HbA1c > 7.5% were referred to diabetes educator and dietitian respectively. For outcome measures, 26% of patients achieved HbA1c < or = 7%, 33% achieved BP < or = 130/80 while 56% achieved LDL < or = 2.6 mmol/L. Aspirin was prescribed in 78% and ACE inhibitor or angiotensin receptor blocker in 91.8% of patients. Lifestyle intervention and complication screening are the two major areas of deficiencies in the care of type 2 diabetic patients in our hospital general medical clinic.
    Study site: General medical clinic, Sarawak General Hospital, Kuching, Sarawak, Malaysia
  5. 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
  6. 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.
  7. 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%.
  8. Teh CL, Wong JS, Soo HH
    Rheumatol Int, 2012 Jan;32(1):265-8.
    PMID: 21243497 DOI: 10.1007/s00296-010-1745-2
    We performed a cross-sectional study of the demography, clinical and laboratory features of patients with polymyositis and dermatomyositis followed up in our centre from 2006 to 2009. There were 12 cases, with the majority of them (58.3%) being woman. They have a mean age of 57.8 years and mean disease duration of 11.83 (SD 9.92) months. Our patients comprised of multi-ethnic groups with predominantly Chinese (83.3%), Sarawak natives (8.3%) and Malays (8.3%). They have a mean lag time to diagnosis of 3.67 (SD 4.27) months. Nine (75%) patients had dermatomyositis and 3(25%) had polymyositis. The common clinical manifestations found in our patients were proximal myopathy (100%), neck weakness (33.3%), dysphagia (33.3%) and interstitial lung disease (33.3%). For the nine patients with dermatomyositis, the most common dermatological manifestations were shawl sign (88.9%) and V sign (88.9%). Muscle enzymes were raised in 91.7% of patients. Electromyographies were carried out in four patients, and only one of our patients had muscle biopsy. Only 41.7% of our patients have positive ANA. The majority received prednisolone (100%) and hydroxychloroquine (58.3%). Malignancy occurred in five (three nasopharyngeal carcinomas, one sigmoid colon cancer and one lung cancer) out of the nine dermatomyositis patients but none in the polymyositis group. The mortality rate in our group was 4(33.3%) over the 4-year period. This study demonstrated the rarity of PM/DM in our centre with considerable lag time to diagnosis in our patients. Despite lack of muscle biopsy in our centre, our centre achieved appropriate diagnosis and management of PM/DM.
  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. Wong JS, Tan F, Lee PY
    Asia Pac J Public Health, 2007;19(3):16-21.
    PMID: 18330400 DOI: 10.1177/101053950701900304
    Achieving treatment targets has been difficult in treating diabetic patients. This cross-sectional study describes the lipid profiles of patients with diabetes mellitus at a public primary health care centre in Sarawak, Malaysia. The targets for lipid control were based on the International Diabetes Federation recommendation (2002). 1031 patients (98% Type 2 Diabetes) were studied. Fasting lipid profiles were available in 990 (96%) patients. The mean total cholesterol was 5.3 +/- 1.0 mmol/L, Triglycerides 1.90 +/- 1.26 mmol/L, HDL-C 1.28 +/- 0.33 mmol/L and LDL-C 3.2 +/- 0.9 mmol/L. Overall, 22% of patients achieved the treatment target for LDL-C level < 2.6mmol/L. 67% of patients had HDL-C > 1.1 mmol/L and 42% of patients had a target TG level below 1.5 mmol/L. Of the 40% of patients who received lipid-lowering drug, 17% achieved LDL-C target, 50% had LDL-C 2.6-4.4 mmol/ L and 33% have LDL-C > 4.0 mmol/L. For the remaining 60% not receiving any lipid lowering therapy, 68% had LDL-C between 2.6-4.0 mmol/L and 7% had LDL-C level > 4 mmol/L. Dyslipidemia is still under-treated despite the availability of effective pharmacological agents and the greatly increased risk of cardiovascular diseases in diabetic patients.
  11. 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.
  12. Nor Zainura Z, Barkeh HJ, Wong JS, Muhaya M
    Med J Malaysia, 2005 Dec;60(5):650-2.
    PMID: 16515120
    This is a case of a 25 year old lady whose eye had been infected by cysticercosis. This case highlighted that the inflammation was due to host immune response. She was treated with oral corticosteroid and the lesions regressed.
  13. 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.
  14. 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.
  15. 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.
  16. Teh CL, Wong JS, Ngeh NK, Loh WL
    Rheumatol Int, 2011 Sep;31(9):1153-7.
    PMID: 20349069 DOI: 10.1007/s00296-010-1435-0
    We performed a cross-sessional study of all systemic lupus erythematosus (SLE) pregnancies during a 4-year period (2006-2009) to describe the clinical features, maternal and foetal outcomes in our centre. There were 48 pregnancies in 44 women with SLE. Our patients have a mean age of 30.0 years (SD 6.36) and a mean disease duration of 40.67 months (SD 48.23). Our patients have complicated pregnancies: 32.7% have SLE flares, 17.3% have preeclampsia and 48.9% needed caesarean sections. There were 20.0% foetal losses and 17.8% preterm deliveries in our patients. SLE flares contributed to 60.0% of foetal losses in our patients. Lupus pregnancies in our centre generally have a good maternal and foetal outcome comparable to developed countries in Asia. The low incidence of APS, the high usage of hydroxychloroquine and the high SLE remission rate in our patients prior to conceptions contributed to the good outcome.
  17. Teh CL, Wong JS, Ngeh NK, Loh WL
    Lupus, 2009 Mar;18(3):278-82.
    PMID: 19213870 DOI: 10.1177/0961203308096661
    We performed a retrospective study of all systemic lupus erythematosus (SLE) pregnancies during a two-year period (2006-2007) to describe the clinical features, maternal and foetal outcomes in our centre. There were 17 pregnancies in 16 women with SLE. Our patients have a mean age of 28.31 years (SD 5.24) and a mean disease duration of 38.62 months (SD 38.03). Our patients have complicated pregnancies: 35.3% have SLE flares, 21.1% have preeclampsia and 47.4% needed caesarean sections. There were 15.8% foetal losses and 12.5% preterm deliveries in our patients. All the foetal losses occurred in patients with severe SLE flares during pregnancies. Lupus pregnancies in our centre generally have a good maternal and foetal outcome comparable with developed countries. The low incidence of antiphospholipid syndrome, the high usage of hydroxychloroquine and the high SLE remission rate in our patients before conceptions are the possible factors contributing to the good outcome.
  18. Ho EL, Ng KH, Wong JH, Wang HB
    Med J Malaysia, 2006 Jun;61(2):204-8.
    PMID: 16898312
    Malaysia's mammography QA practice was surveyed based on the Malaysian Ministry of Health and the American College of Radiology (ACR) requirements. Data on mammography unit, processor, image receptor, exposure factors, mean glandular dose (MGD), sensitometry, image quality and viewbox luminance were obtained. Mean developer temperature and cycle time were 34.1 +/- 1.8degreesC and 107.7 +/- 33.2 seconds. Mean base+fog level, speed index and contrast index were 0.20+/-0.01, 1.20+/-0.01 and 1.33+/-0.26 respectively. Eighty-six percent of the fifty centres passed the image quality test while 12.5% complied with ACR recommended viewbox luminance. Average MGD was 1.0+/-0.4 mGy. Malaysia is on the right track for QA but with room for total quality improvement.
  19. Yuen KH, Wong JW, Yap SP, Billa N
    Int J Clin Pharmacol Ther, 2001 Jan;39(1):37-40.
    PMID: 11204936
    OBJECTIVE: The aim of the present communication is to provide information regarding the intrasubject coefficent of variation obtained from 30 bioequivalence studies covering 16 drugs which can be used for estimation of sample size. Additionally, an attempt was also made to estimate the test power of each of the studies conducted.

    METHODS: The intrasubject coefficient of variation was estimated from the residual mean square error obtained from analysis of variance of the parameters AUC0-infinity, Cmax and Cmax/AUC0-infinity after logarithmic transformation. The test power in the analyses of the above parameters was subsequently estimated using nomograms provided by Diletti et al. [1991].

    RESULTS AND CONCLUSION: Thirty products covering 16 drugs were studied in which 22 were immediate-release (including one dispersible tablet) and 8 were sustained-release formulations. The intrasubject coefficient of variation for the parameter AUC0-infinity was smaller than Cmax, and hence considerably more studies were able to attain a power of greater than 80% using 12 volunteers for the AUC0-infinity, compared to the Cmax. However, the variability in the Cmax could be reduced by using the parameter Cmax/ AUC0-infinity, and thus, provide a more realistic estimation of sample size, since the latter reflects only the rate of absorption and not both the rate and extent as in the case of Cmax [Endrenyi et al. 1991].

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